impact of elevated dissolved co john david pugh rona …

IMPACT OF ELEVATED DISSOLVED CO2

ON AQUIFER WATER QUALITY

by

JOHN DAVID PUGH

RONA J. DONAHOE, COMMITTEE CHAIR

CHUNMIAO ZHENG

FRED ANDRUS

GEOFF TICK

JAMES REDWINE

A DISSERTATION

Submitted in partial fulfillment of the requirements

for the degree of Doctor of Philosophy

in the Department of Geological Sciences

in the Graduate School of

The University of Alabama

TUSCALOOSA, ALABAMA

2015

Copyright John David Pugh 2015

ALL RIGHTS RESERVED

1

ABSTRACT

The focus of the current study was to thoroughly characterize the properties of a typical

Gulf Coast potable aquifer for purposes of performing a controlled CO2 release experiment and

to construct coupled geochemical and transport models capable of predicting impacts from CO2

migration into a drinking water aquifer. The aquifer is a methanogenic environment composed

primarily of quartz and feldspars, with minor or trace amounts of pyrite, mica, illite, smectite,

and kaolinite. The formation water is dominantly Na-HCO3, consistent with the theory and

PHREEQC modeling results that suggest aquifer freshening and ion exchange have played

dominant roles in determining the present-day dissolved major ion composition.

This study also presents the design and implementation of a closed loop pumping and

injection system designed to simulate CO2 leakage into a test site aquifer. Process monitoring

results indicated that the test was performed with minimal variation in key process parameters,

including temperature, pressure and injectate pH. In situ instrumentation deployed in monitoring

wells allowed continuous readings of groundwater pH and conductivity, which were critical

parameters for evaluating the aquifer response to carbonation and acidification. Successful

modeling simulation of the pH response using results from the aquifer testing program suggested

that the test was implemented and monitored appropriately and that that future data

interpretations and modeling of the field experiment were not compromised by test design.

Test results showed that no constituent was mobilized in excess of US EPA maximum

contaminant levels, but that many constituents (primarily major and minor cations) were released

in a pulse-like response at levels above their baseline concentrations. Dissolution of trace

iii

carbonate and pyrite in the aquifer are hypothesized to have triggered cation exchange reactions,

a dominant geochemical process affecting major and minor cation behavior in the aquifer. The

test has shown that migration of carbon dioxide into a drinking water aquifer can mobilize ions

into solution, but at levels that may not exceed EPA MCLs under the field conditions tested for

this specific system. Data presented here are potentially applicable to assessments across the

Gulf Coast, where the potential for deep geologic carbon sequestration is high.

iv

DEDICATION

I dedicate this dissertation Graham David Pugh, in hopes that he will never stop pursuing his

dreams.

v

LIST OF ABBREVIATIONS AND SYMBOLS

CCS carbon capture and storage

CEC cation exchange capacity

cm centimeter

cu uniformity coefficient

d10 effective grain size (cm)

d50 mean grain size (mm)

DOE Department of Energy

e-

electron

Eh Reduction potential

EPA Environmental Protection Agency

EPRI Electric Power Research Institute

ft feet

gpm gallons per minute

GS geologic sequestration

hr hour

j exponent

Kh hydraulic conductivity

L liter

LC-MS liquid chromatography – mass spectrometry

M meter

vi

MCL maximum contaminant level

MDEQ Mississippi Department of Environmental Quality

mg milligram

min minutes

mm millimeter

MSL mean sea level

mV millivolts

µg microgram

µmhos micromhos

NC not calculated

n.t.u. nephelometric turbidity units

NWIS U.S. National Water Information System

pH acidity

PVC poly-vinyl chloride

r2 correlation coefficient

sec second

SECARB Southeast Regional Carbon Sequestration Partnership

SEM scanning electron microscope

S.I. saturation index

s.u. standard units

TOC total/dissolved organic crabon

US United States

USGS United States Geological Survey

vii

X ion exchange surface

XRD X-ray diffraction

viii

ACKNOWLEDGEMENTS

I thank my advisor Dr. Rona Donahoe for making this happen. My wife, Sarah, and son,

Graham David, are the ultimate inspiration for following through. My families in South Carolina

and Ohio have encouraged me greatly. The people at Southern Company have been more than

generous letting me squeeze this into a busy work schedule, and the Department of Geological

Sciences has been very accommodating. Thanks to Plant Daniel, James Douglas, Kheushla

Powe, Dan Patel and Rick Hagendorfer for supporting the project design and implementation.

Thanks to Rob Trautz and the Electric Power Research Institute (EPRI) for project direction and

funding.

ix

CONTENTS

ABSTRACT .................................................................................................................................... ii

DEDICATION ............................................................................................................................... iv

ACKNOWLEDGEMENTS ......................................................................................................... viii

LIST OF TABLES .......................................................................................................................... x

LIST OF FIGURES ....................................................................................................................... xi

INTRODUCTION .......................................................................................................................... 1

GEOCHEMICAL CHARACTERIZATION OF THE GRAHAM FERRY AQUIFER IN

COASTAL MISSISSIPPI ............................................................................................................... 9

DESIGN AND IMPLEMENTATION OF A FIELD EXPERIMENT EVALUATING

IMPACTS OF CO2 LEAKAGE INTO A CONFINED AQUIFER ............................................. 53

GEOCHEMICAL IMPACT OF A CONTROLLED CO2 RELEASE FIELD TEST ON A

SHALLOW POTABLE COASTAL PLAIN AQUIFER ............................................................. 80

SUMMARY ................................................................................................................................ 115

APPENDICES ............................................................................................................................ 119

x

LIST OF TABLES

Table 2.1 Sediment characteristics ............................................................................................... 21

Table 2.2. Well slug test results. ................................................................................................... 23

Table 2.3 Summary of field parameter data during baseline sampling ........................................ 25

Table 2.4 Summary of baseline major and minor cation and anion concentrations. .................... 26

Table 2.5 Summary of trace element data during baseline sampling ........................................... 30

Table 2.6. Groundwater major ion concentrations measured in the current study and

previously reported for the Miocene aquifer system in Mississippi (MDEQ 2013). .................... 39

Table 2.7. Typical CO2-generating reactions in groundwater systems. ........................................ 44

Table 3.1. Well spacing distances and injection rates. ................................................................. 56

Table 3.2. Aquifer properties and water column pressures. ......................................................... 59

Table 4.1 Summary of cation and anion concentrations compared to US EPA MCLs ................ 85

Table 4.2 Summary of trace element concentrations compared to US EPA MCLs ..................... 86

Table 4.3 Summary of stationary and non-stationary chemical parameters during the

baseline sampling period............................................................................................................... 87

Table 4.4 Summary of statistical exceedances above background in each well for each cation . 88

Table 4.5 Summary of test period durations and sampling schedule ........................................... 89

Table 4.6 Response to CO2 behavioral categories ...................................................................... 103

xi

LIST OF FIGURES

Figure 2.1 Site location and regional geologic cross section ........................................................ 11

Figure 2.2 Well locations .............................................................................................................. 12

Figure 2.3 Photo of well-field (well BG-1 not shown) ................................................................. 13

Figure 2.4 Typical well construction detail (showing BG-1) ....................................................... 15

Figure 2.5 Sands and gravels from the Citronelle (a and b) and fine,silty sand from the

Graham Ferry (c)........................................................................................................................... 19

Figure 2.6. Study site cross-section, illustrating sequence of clay and sand units beneath

the test site..................................................................................................................................... 20

Figure 2.7 Scanning electron photomicrograph showing (a) quartz and pyrite, (b) pyrite

framboid (magnified from (a)), (c) quartz gypsum and pyrite and (d) gypsum and pyrite

(magnified from square area in (c)). ............................................................................................. 22

Figure 2.8. Pumping test results showing displacement versus time curves for PW-1,

MW-1, and IW-1. .......................................................................................................................... 24

Figure 2.9 Spatial variability of Ca, Mg, Na and K during baseline sampling ............................. 27

Figure 2.10 Spatial variability of Fe, Ba, Mn and Sr during baseline sampling ........................... 28

Figure 2.11 Spatial variability of SO4 during baseline sampling.................................................. 29

Figure 2.12 Groundwater sulfate, carbonate, and sulfide saturation indices box-and-whisker

plots (triangle indicates the average and vertical bars represent maximum and minimum values).

....................................................................................................................................................... 32

Figure 2.13. Histograms of groundwater carbonate mineral saturation indices. ......................... 33

Figure 2.14. Groundwater aluminum, iron, and manganese oxyhydroxide mineral saturation

indices box-and-whisker plots. ..................................................................................................... 34

Figure 2.15. Groundwater silicate mineral saturation indices box-and-whisker plots. ............... 35

xii

Figure 2.17. Hydraulic conductivity measurements of the current study, for the Graham

Ferry aquifer and other Gulf Coast aquifers, and values estimated for typical sediment grain

size classifications. ........................................................................................................................ 37

Figure 2.17. Conceptual model illustrating aquifer freshening of saline groundwater (X

represents the exchangeable mole fraction). ................................................................................. 40

Figure 2.18. Results of a simple PHREEQC rainwater-saline water mixing model showing

trends in groundwater major ion concentrations over time during aquifer freshening. ................ 41

Figure 2.19. Aquifer freshening trends of groundwater major ion concentrations modeled

using PHREEQC and incorporating ion exhange (Exchangeable mole fraction (X) = 0.03;

Ca-montmorillonite, calcite, and K-feldspar allowed to dissolve and illite allowed to

precipitate). ................................................................................................................................... 42

Figure 2.20 Plot illustrating relationship between excess sodium and depletions in Ca+Mg

in the Miocene aquifer in Mississippi and similarity to the Texas Gulf Coast. ............................ 43

Figure 2.21. Relationship between pH and degree of CO2 supersaturation in groundwater,

showing a higher degree of supersaturation at lower pH. ............................................................. 45

Figure 2.22. Histogram of groundwater pH measurements during the baseline study period. .... 45

Figure 2.23. Relationship between measured Eh values and Eh calculated using measured

concentrations of redox pairs. ....................................................................................................... 47

Figure 2.25. Possible stages of geochemical evolution of the study site aquifer over

geologic time (FeS(m) = mackinawite). ....................................................................................... 49

Figure 3.1. Well field layout. ........................................................................................................ 56

Figure 3.2 Site cross-section illustrating the injectate fluid delivery system. .............................. 58

Figure 3.3. Carbonation and injection system photograph. .......................................................... 59

Figure 3.4 Picture showing dedicated bladder pump and well completion. ................................. 61

Figure 3.5 Schematic showing the pressurized monitoring well sampling system. ..................... 62

Figure 3.6. Injectate water pH during the test period, showing pre- and postcarbonation pH. .... 63

Figure 3.7. Inlet and outlet water temperature during the test period. .......................................... 63

Figure 3.8. Inlet and outlet water pressure during the test period. ................................................ 64

Figure 3.9. Injectate water flow rate measured during the test period. ......................................... 65

xiii

Figure 3.10. Potentiometric groundwater elevations in all monitoring wells during the test

period. ........................................................................................................................................... 65

Figure 3.11. Approximate hydraulic gradient and injectate flow rate during the test period. ...... 66

Figure 3.12. Downhole groundwater pH measurements during the test period. .......................... 67

Figure 3.13. Downhole groundwater conductivity measurements during the test period. ........... 68

Figure 3.14. Downhole and surface pH measurements for well MW-1 groundwater. ................. 69




Figure 3.18. Relationship between pH and dissolved CO2 to PCO2. .............................................. 72

Figure 3.19. Representation of the PHREEQC 1-D column transport model. ............................. 74

Figure 3.20. Measured and modeled groundwater pH in down-gradient well MW-3.

Groundwater pH was modeled using a PHREEQC 1-D transport model without buffering

reactions. ....................................................................................................................................... 75

Figure 4.1 Box-and-whisker plots illustrating stationary and non-stationary baseline datasets ... 87

Figure 4.2 pH trends during baseline, injection and post-injection time periods. ........................ 90

Figure 4.3 Eh trends during baseline, injection and post-injection time periods. ......................... 91

Figure 4.4 Conductivity trends during baseline, injection and post-injection time periods. ........ 91

Figure 4.5 Alkalinity trends during baseline, injection and post-injection time periods. ............. 92

Figure 4.6 Calcium trends during baseline, injection and post-injection time periods................. 93

Figure 4.7 Trends of ferrous and ferric iron, showing markedly different responses during

the CO2 injection but similar post-injection behavior................................................................... 94

Figure 4.8 Silicon trends during baseline, injection and post-injection time................................ 94

Figure 4.9 Trends of potassium and lithium, showing responses to CO2 injection against

highly variable baseline concentrations. ....................................................................................... 95

Figure 4.10 Sodium trends during baseline, injection and post-injection time. ........................... 96

xiv

Figure 4.11 Trends of Al, Cu, Pb, Hg, Zn and Sb, showing sporadic nature of detection

throughout all test periods. ............................................................................................................ 97

Figure 4.12 Molybdenum concentrations over time, showing decreases in concentration

following CO2 injection ................................................................................................................ 98

Figure 4.13 Trends of Ni, Co, Cr and Be, showing increasing trends during the CO2

injection phase. Relationship of Co and Ni trends to CO2 injection are suspect due to

timing of response in multiple wells. ............................................................................................ 99

Figure 4.14 Trends of chloride concentrations, showing mostly stable concentrations

during the test period. ................................................................................................................. 100

Figure 4.15 Trends of sulfate concentrations, showing an increase during the active

injection period. .......................................................................................................................... 101

Figure 4.16 Trends of fluoride concentrations, showing decreases during the injection

period. ......................................................................................................................................... 101

Figure 4.17 Trends of dissolved organic carbon, showing increases during the injection

period. ......................................................................................................................................... 102

Figure 4.18 Nickel and cobalt trends, showing possible impact from downhole probes. .......... 105

Figure 4.19 Saturation indices of siderite, calcite, dolomite and rhodochrosite, suggesting

the possibility of carbonate dissolution and release of Ca, Mg, Mn and Fe. .............................. 107

Figure 4.20 Eh-pH diagram illustrating stability fields of ferrous iron, Fe(OH)3am, and

pyrite. .......................................................................................................................................... 108

Figure 4.21 Relationship between molybdenum and pH during the experiment. ...................... 109

Figure 4.22 Cross-well resistivity monitoring results (Wu et al., 2012), illustrating

progression of high-conductivity plume past MW-3 over time. ................................................. 110

1

Chapter 1

INTRODUCTION

Carbon capture and storage (CCS), specifically by means of geologic sequestration (GS),

is a developing technology to reduce CO2 emissions to the atmosphere. This technology

involves separating CO2 from flue gas and transporting the CO2 to underground storage locations

that are isolated from the atmosphere. These storage locations are typically permeable and

porous geologic formations that are not useful for any other purpose, such as drinking water.

NETL (2012) estimated that between 1,610 and 20,155 gigatons of CO2 may be stored by

means of GS in the United States, mostly in saline formations. The Department of Energy

(DOE) created Regional Carbon Sequestration Partnerships to gather data regarding the

effectiveness and safety of GS in different regions of the United States. Various geologic

settings are being evaluated, including depleted oil and gas fields, un-mineable coal seams, saline

formations, and shale and basalt formations. Studies have since indicated that the Southeastern

United States Coastal Plain region is home to large potential CO2 sinks. In this region, deep

saline formations, coal seams, and oil and gas reservoirs will be opportunistic storage formations

for CO2 sequestration.

The large capacity for CO2 storage in the Southeastern U.S. Coastal Plain, however, has

created the need to evaluate the risk of contamination to potable water supplies resting above

target storage formations (Apps et al., 2008). Celia and Nordbotten (2009) reviewed three

scenarios in which CO2 may leak out of the target formation: 1) diffusive leakage through

caprock, 2) leakage through faults and fractures, and 3) leakage through abandoned oil or gas

2

wells in the area. Leakage under any of these three scenarios may result in secondary plumes

forming in permeable layers above the target formation, a portion of which may enter a potable

water supply. Gas-phase CO2 will continue to migrate vertically, whereas dissolved CO2 will

migrate in the direction of regional groundwater flow (Celia and Nordbotten, 2009).

The primary risk to potable water supplies due to CO2 leakage into the aquifer will result

from the reactions between dissolved CO2 and the host aquifer mineral assemblage (Apps et al.,

2008; Harvey et al., 2012). One such reaction is the dissolution of carbonate minerals such as

calcite (Langmuir, 1997):

(1) CaCO3 + CO2(g) + H2O = Ca2+

+ 2HCO3-

Carbonate mineral dissolution can release elements such as calcium, magnesium, iron,

and manganese to solution, in addition to other carbonate-forming minor and trace elements. In

the absence of significant acid buffering capacity, the dissociation of carbonic acid can produce

pronounced acidity in the form of H+. In these systems, other important reactions may include

the pH-dependent surface complexation of trace elements onto iron oxyhydroxides or other

sorbent surfaces, as represented by the following surface complexation reaction between arsenate

and iron oxyhydroxide:

(2) ≡FeOH-1/2

+ 2 H+ + AsO4

-3 = ≡FeOAsO3H

-3/2 + H2O

where ≡FeOH-1/2

represents a surface functional group on iron oxyhydroxide, and ≡FeOAsO3H-

3/2 represents a monodentate inner-sphere surface species wherein arsenic is bound to the iron

oxyhydroxide surface (EPRI, 2009). In reducing environments, iron sulfide mineral

solubilization may result in release of dissolved iron and sulfur, and possibly to other trace

element impurities, by a reaction such as that for mackinawite dissolution:

3

(3) FeS + H+ = Fe

2+ + HS

-

The specific reactions that take place will depend entirely on the aquifer initial conditions,

including pH, redox state, mineral assemblage, temperature, and pressure.

Screening-level studies have simulated the interactions of injected CO2 with formation

fluids and minerals, providing guidance regarding what factors may be most important with

respect to sequestration mechanisms such as mineralization (Bachu and Adams, 2003; Xu et al.,

2004; Xu et al., 2007; Zerai et al., 2006; Wigand et al., 2008). These studies have focused

primarily on estimating the carbon sequestration capacity of deep, non-potable aquifer systems.

In most cases, a limited range of scenarios are evaluated, based upon “typical” characteristics of

potential receiving formations. For example, Xu et al. (2004) analyzed the impact of CO2

immobilization through carbonate mineral precipitation in the following aquifer settings: a

glauconitic sandstone representative of the Alberta Sedimentary Basin, Gulf Coast Mesozoic and

Tertiary sandstones representative of saline aquifers in offshore Texas, and a dunite reservoir.

The authors evaluated the mass of CO2 that could be immobilized by alteration of these mineral

assemblages at elevated temperatures and pressures.

Many studies have focused simulation efforts on assessing risks posed to potable water

supplies by intrusion of CO from deep storage reservoirs (Apps et al., 2008; Zheng et al., 2008;

Zheng et al., 2009). Apps et al. (2008) conducted a nationwide assessment of aquifer

equilibrium conditions, based on water quality data from the U.S. National Water Information

System (NWIS). The study involved calculating mineral saturation indices for the nation’s water

supply aquifers in an effort to establish initial equilibrium conditions which may be perturbed if

CO2 migrated into the aquifer. Minerals known to host trace elements in coal and ore deposits

were evaluated, and those found to exhibit near-saturation in the representative aquifer were

4

assumed to be present in the aquifer. In this fashion, theoretical aquifer mineral assemblages

were constructed using data derived from multiple sources.

In a companion study, Zheng et al. (2008) subjected the constructed equilibrium

conditions established by Apps et al. (2008) to a simulated intrusion of CO2. An important

conclusion of the study was that arsenic may be mobilized to concentrations exceeding the

United States Evironmental Protection Agency’s (US EPA) maximum contaminant level (MCL)

of 10 µg/L in certain aquifer settings, particularly those containing arsenopyrite and appreciable

sorption capacity. In one scenario, the total arsenic present was quantified as the sum of three

reservoirs: 1) dissolved arsenic; 2) arsenic in arsenopyrite, and 3) arsenic adsorbed to clay

minerals such as illite. Perturbation to the system resulted in an initial mobilization of sorbed

arsenic to levels exceeding the MCL, followed by increased sorption and long-term

immobilization of the released arsenic as pH decreased. The relative magnitudes of arsenic

release and long-term attenuation were found to be most sensitive to the sorption capacity of the

aquifer system. Low sorption capacity resulted in lower initial dissolved concentrations, but also

produced less capacity for long-term attenuation of mobilized arsenic. On the other hand, higher

sorption capacity created the risk of mobilizing more arsenic initially, but provided the advantage

of greater long-term attenuation capacity. A general conclusion of the study was that several

scenarios are possible, and that site-specific characteristics will govern the extent of reactions

that may pose risk to the water supply.

Confidence in modeled results is greatly enhanced if they are shown to be comparable to

field observations (Xu et al., 2004). Kharaka et al. (2009) and EPRI (2008) provided evidence

that primary geochemical effects resulting from CO2 intrusion into an aquifer system are

carbonate and oxide mineral dissolution. Kharaka et al. (2009) reported geochemical changes in

5

a 1500 m deep sandstone aquifer, following injection of CO2 into the Frio Sandstone in Texas.

A drop in pH to approximately 3 standard units (s.u.) due to CO2 dissolution was interpreted to

have mobilized significant calcium, iron, and manganese from carbonates and metal oxides.

Likewise, EPRI (2008) injected CO2 into a shallow, unconfined aquifer system and observed a

decrease in pH – from pH 7 to 6 – and increased dissolved bicarbonate, calcium, and

magnesium. The test results were ultimately difficult to model and interpret due to the

occurrence of gas exsolution from the aquifer into the vadose zone, and subsequent redissolution

of CO2 into the water table farther downgradient. More recently, field push-pull tests have been

conducted at two sites, one in a shallow Gulf Coast aquifer in Cranfield, Missisippi (Yang et al.,

2013) and another in southern France (Rillard et al., 2014). Yang et al. (2013) reported a low

risk of trace element mobilization, with dominant reactions being silicate dissolution, ion

exchange, desorption and dissolution of trace amounts of carbonates. Rillard et al. (2014)

reported significant mobilization of Ca and Mg, and limited mobilization of Fe, Mn, Zn and As.

Karamalidis et al. (2013) suggested that Cr, Pb, Mn, and Fe could exceed EPA MCLs in

sandstone reservoirs reacting with CO2. In laboratory studies, Lu et al. (2010) proposed a

behavior-based categorization of element response to CO2: Type 1 and Type 2. In their

laboratory experiments, Type 1 elements (Ca, Mg, Si, K, Sr, Mn, B, Zn) were observed to

increase and remain elevated after exposure to CO2;Type 2 elements (Fe, Al, Mo, U, V, As, Cr,

Cs, Rb, Ni, Cu) were observed to increase rapidly and then decrease to baseline concentrations.

Proper assessment of risk will require development of models capable of predicting

impacts to drinking water sources, and the testing of models against field observations. The

objectives of this study are to:

6

1. Investigate whether sequestered CO2 released from a geologic storage reservoir will have

an adverse impact on underground sources of drinking water from a dominantly quartz-

rich aquifer, and

2. Identify geochemical mechanisms responsible for releasing elements under carbonated

conditions.

In order to achieve these objectives, a thorough geochemical and physical characterization of a

test aquifer was conducted, dissolved CO2 was injected into the test aquifer, and the groundwater

monitored for metals mobilization.

This dissertation consists of three main chapters. In Chapter 2, the baseline geochemical

and physical characterization of the test site is documented and compared to other sites in the

Southeastern United States. This effort is critical to understanding future impacts to the test site.

In Chapter 3, an innovative field test design is described in detail so that the test results can be

interpreted with confidence. The design and approach are critical to enable valid interpretation

of the results. Finally, Chapter 4 focuses on the results of the test, evaluating monitoring well

data from a statistical and regulatory perspective, in addition to interpreting the geochemical

data. Preliminary results from the study and companion laboratory and field studies from the

subject test site have been previously published (Dafflon et al., 2012; Trautz et al., 2012;

Varadharajan et al., 2013). All of the material in this dissertation represents original work.

7

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Zheng, L., J.A. Apps, Y. Zhang, T. Xu, and J.T. Birkholzer, 2009. On mobilization of lead and

arsenic in groundwater in response to CO2 leakage from deep geological storage.

Chemical Geology, Vol. 268, No. 3-4, pp. 281-297.

9

Chapter 2

GEOCHEMICAL CHARACTERIZATION OF THE GRAHAM FERRY AQUIFER IN

COASTAL MISSISSIPPI

Abstract

The focus of the current study was to thoroughly characterize the properties of a typical

Gulf Coast potable aquifer for purposes of performing a controlled CO2 release experiment and

to construct coupled geochemical and transport models capable of predicting impacts from CO2

migration into a drinking water aquifer. The aquifer is a methanogenic environment composed

primarily of quartz and feldspars, with minor or trace amounts of pyrite, mica, illite, smectite,

and kaolinite. Chemical disequilibrium is suggested by comparing aquifer mineralogy to

calculated mineral saturation indices and by the presence of dissolved ferric iron under

methanogenic conditions. The formation water is dominantly Na-HCO3, consistent with the

theory and PHREEQC modeling results that suggest aquifer freshening and ion exchange have

played dominant roles in determining the present-day dissolved major ion composition.

Ultimately, data from this study were used to design and implement a controlled CO2 release

field test at the site evaluating real-world impacts to an aquifer due to elevated CO2. Data

presented here are potentially applicable to assessments across the Gulf Coast, where both the

potential for deep geologic carbon sequestration and continued reliance upon groundwater

resources are high.

10

1. Introduction

In order to successfully permit geologic CO2 sequestration projects, the potential

impacts from CO2 leakage into drinking water aquifers must be addressed, either through

predictive modeling or direct experimentation. In 2009, a controlled release field test was

initiated to evaluate potential impacts of carbon dioxide leakage into a shallow aquifer in the

Gulf Coast region of the United States (Trautz et al., 2013). The test was designed so that

thorough aquifer characterization prior to implementing the test would foster the production of

coupled geochemical and transport models capable of reproducing experimental results. If

successful, predictive modeling efforts can be used to help evaluate impacts without the need for

further extensive field testing at every potential sequestration site.

The purpose of Chapter 2 is to describe the baseline physical and geochemical

characteristics of the test site aquifer. Slug testing, pumping tests and grain size analyses were

used to define the flow characteristics of the test aquifer. Major, minor, and trace element data

were collected, in addition to dissolved gases, redox indicators, and other field parameters such

as pH, temperature, and conductivity. Physical and geochemical characteristics of the aquifer are

used to evaluate the broader applicability of the study to other Gulf Coast settings.

2. Site Location and Regional Hydrogeologic Setting

The Plant Daniel power plant site, located just north of Pascagoula Mississippi (Figure

2.1), was chosen due to a variety of factors. First, the site was host to a previous deep geologic

CO2 injection test implemented by the Southeast Regional Carbon Sequestration Partnership

(SECARB) Program and sponsored by the U.S. Department of Energy (DOE) (SECARB, 2008).

The fact that the site overlies favorable geology for purposes of CO2 sequestration makes it ideal

11

for assessing the potential water quality impacts to overlying potable aquifers. Also, due to the

aquifer’s confinement and location beneath a large controlled-access property, the study area

posed minimal risk to surrounding property owners and water supplies.

Figure 2.1 Site location and regional geologic cross section

.

Hancock

Harrison

Jackson

A

A’

WestA

EastA’

0

-1,000

-2,000

-3,000

-4,000

-5,000

Base of Freshwater (1,000 mg/L TDS)

Depth(feet)

10 miles

Key:

Site Location

Gulf of Mexico

AL

LA

N

12

The Pliocene-Miocene Aquifer System underlying Jackson County is comprised of the

Catahoula, Hattiesburg, Pascagoula, Graham Ferry, and Citronelle formations. Sand beds in the

Graham Ferry and Pascagoula formations provide the primary water supply along the coast. The

formations consist of alternating beds of sands and clays which were deposited in a deltaic or

near-shore marine environment. The Graham Ferry Formation is most widely used in the

vicinity of Pascagoula, MS. Sands thin toward eastern Jackson County, and generally dip and

thicken toward the coast (MDEQ, 2000).

3. Methods

3.1. Drilling and well installation

Site drilling investigations proceeded in two stages. Wells PW-1, MW-1, and MW-2

were installed during January and February of 2010. These wells were used to perform a

preliminary pumping test so that additional wells could be properly located for the experiment.

Wells IW-1, MW-3, MW-4, and BG-1 were installed in August 2010 (Figure 2.2), after

preliminary flow modeling indicated proper well spacing across the test field (Trautz et al.,

2013). The well field is shown in Figure 2.3.

Figure 2.2 Well locations

BG-1

IW-1MW-3

MW-4

PW-1

MW-1

MW-2

Background

Monitoring Well

Pumping Well

Injection

Well

Downgradient

Monitoring Wells

15 ftN

13

Figure 2.3 Photo of well-field (well BG-1 not shown)

All boreholes were drilled using the rotosonic drilling technique, and core samples were

collected from selected horizons within, above, and below the target test interval using 1.52 m

Lexan® (polycarbonate) tubes inside of a stainless steel core barrel. When extracted from the

steel outer core barrel, the Lexan® tubes were immediately capped on both ends to prevent

fallout of recovered sediment and to reduce exposure to the atmosphere. The tube was then cut

using a stainless steel blade handsaw into sections of desired length, capping each end

immediately after cutting. All sections were placed on frozen blue ice beneath dry ice and

cooled in the field. Samples were kept frozen using dry ice until shipped overnight to Lawrence

Berkeley National Laboratory.

MW-2

PW-1

MW-4

IW-1

MW-3 MW-1

14

Monitoring wells consisted of 4-inch PVC riser pipe with 4.57 meter screened intervals.

Screened intervals consisted of 0.01-inch machine-slotted openings; clean, quartz sand filter

packs were emplaced to achieve adequate holdback of formation sediments. Filter sand was

extended to 0.6 m above the screened interval, and 0.6 to 0.9 m of bentonite pellets were

emplaced immediately above the filter pack sand. After allowing the bentonite time to hydrate

and swell, a bentonite-cement grout mixture was poured between the riser pipe and borehole

walls to seal the well from leakage and provide structural integrity. Wells were completed with

0.6 m x 0.6 m concrete pads for surface protection. A typical well construction detail is shown

in Figure 2.4.

Wells were initially developed using a submersible pump, drawing at a rate of 56.7 liters

per minute (L/m). Each well was pumped for 4 hours, until the water was visually clear. Wells

were developed further on 9/1/10 and 9/2/10, using a submersible pump drawing at a rate of 15.1

L/m. Wells were pumped until turbidity levels dropped below 10 nephelometric turbidity units

(NTU) and other parameters [pH, temperature, conductivity, dissolved oxygen, turbidity, and

oxidation-reduction potential (ORP)] stabilized.

3.2. Slug testing and pump testing

Slug tests were conducted by lowering a PVC cylinder, or “slug”, of known volume into

the well and recording changes in water levels using downhole pressure transducers. Baseline

water level data were first recorded prior to lowering the slug into the well. After lowering the

slug into the well, water exited the well into the formation and water levels were allowed to

return to baseline conditions before raising the slug from the well. After raising the slug from

the well, water was allowed to enter the well from the formation.

15

The changes in water levels over time were used to compute values for horizontal hydraulic

conductivity, using both the Hvorslev (1951) and the Bouwer and Rice (1976) methods.

Figure 2.4 Typical well construction detail (showing BG-1)

BG-1

Hole diameter: 8”

Well casing diameter: 4”

Bottom of hole: 182’

Bentonite: 182-178’

20/30 Filter sand: 178-177.5’

Screened: 177.5-162.5’

20/30 Filter sand: 162.5-160’

30/65 Filter sand: 160-159.5’

Bentonite: 159.5-157.2’

Bentonite/cement: 157.2-0’

Brown sandy clay with organics (0-15’)

Tan and white fine sand with silt (15-19’)

Light green and gray clayey silt (19-23’)

Gray/tan/orange silty fine-coarse sand

w/gravel and wood fragments (23-63’)

Olive-gray clay (63-76’)

Light brown/tan/orange/gray silty fine-coarse

Sand w/gravel (76-108’)

Green clay (108-151’)

Gray/green clayey fine sand (151-156’)

Gray silty fine sand (156-178’)

Green clayey sand (178-182’)

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

Dep

th (

ft)

16


Two pumping tests were also performed: an 18-hr test and a 39-hr test. The 18-hr

constant rate pumping test was performed using MW-2 as the pumping well, and MW-1 and

BW-1 as observation wells. The well was pumped at a rate of 18.9 L/m, and water level

observations were recorded at 2 second intervals throughout the test, using downhole pressure

transducers. A 39-hr pumping test was run beginning 9/23/10. Well PW-1 was pumped at a

constant rate of 18.9 L/m for the majority of the test. However, the initial pumping rate until 42

minutes into the test was documented as 22.7 L/m. Water level drawdown were measured and

recorded over time in wells MW-1 and IW-1. Data were analyzed using AQTESOLV™ aquifer

test data analysis software (HydroSOLVE, Inc., 2006).

3.4. Groundwater sampling and analysis

Wells were sampled using dedicated QED™ bladder pumps and following EPA-

recommended low-flow sampling procedures (US EPA, 1996). During purging at 0.76 L/m,

water from the well was expelled from a bladder to the surface and into a sampling tube. The

tubing was connected to an in-line flow-through cell where measurements of pH, dissolved

oxygen, conductivity, temperature, and oxidation-reduction-potential were made. When these

parameters stabilized, samples were collected upstream of the flow-through cell into appropriate

containers with preservatives. Samples were placed on ice (if necessary) and immediately

delivered, or shipped overnight, to the laboratory for analysis.

Field measurements were conducted for alkalinity, ferrous iron and total sulfide.

Alkalinity titrations were performed on non-filtered samples using a HACH® digital titrator

following an EPA-compliant HACH® method 8203. Ferrous iron measurements were made

17

using a 1,10 phenantholine iron reagent colorimetric method HACH® test kit with a range of

0.0-10.0 mg/L. Field sulfide was measured using a HACH® model HS-WR colorimetric kit.

Laboratory analyses were performed by TestAmerica, Inc. in Pensacola, FL. Major,

minor and trace cations were analyzed using either inductively coupled plasma (ICP) (Li, Fe, Si)

or inductively coupled plasma-mass spectrometry (ICP-MS) (Al, Ba, Ca, K Mg, Mg, Na, Sr, Ag,

As, Be, Co, Cd, Cr, Cu, Mo, Ni, Pb, Sb, Se, Tl, Zn) following US EPA (1994). Mercury (Hg)

was determined using cold vapor atomic absorption (CVAA) following US EPA (1994).

Dissolved phosphorous (P) was analyzed according to colorimetric method EPA 365.4 (US EPA,

1974). Anions Br, Cl, F, and SO4 were determined using ion chromatography (IC) following

MCAWW (1983). Total and bicarbonate alkalinity were analyzed following titration method

SM2320B (APHA, 2012). Nitrate (NO3), nitrite (NO2) and ammonia (NH3) were analyzed using

ion selective electrodes following SM4500. Dissolved gases methane (CH4), ethane (C2H6),

ethylene (C2H4), carbon dioxide (CO2), carbon monoxide (CO), oxygen (O2) and nitrogen (N2)

were analyzed in the laboratory using gas chromatography (GC) following RSK 175 (US EPA,

2004). Dissolved sulfide was measured in the laboratory by titrimetry following US EPA

(1978). Acetic acid, propionic acid, pyruvic acid, n-butyric acid, and lactic acid were analyzed

using direct aqueous injection into gas chromatograph (TestAmerica, 2014). Dissolved organic

carbon was measured following EPA method 415.1 (MCAWW, 1983).

3.5. Sediment characterization (X-ray diffraction, scanning electron microscopy, cation

exchange capacity)

Select sediment samples were delivered to the University of Alabama, Department of

Geological Sciences, who performed semi-quantitative X-ray diffraction (XRD) analysis to

determine sample mineralogy. Scanning electron microscope (SEM) images were performed by

18

the Southern Company Services, Inc. metallurgy department. The samples were examined in a

Hitachi S-3700N Scanning Electron Microscope after being placed on a carbon backing. Oxford

Instruments INCA X-ACT model number 51-ADD0030 Electron Dispersive Spectroscopy

apparatus was used to identify the elemental composition of the individual samples. All images

and elemental spectra were taken in variable pressure mode at 20 Pa. at 30.0kV. All images

were recorded with the backscatter electron detector, with quadrants biased to enhanced

topographic contrast. Cation exchange capacity (CEC) measurements were performed by Charu

Varadharajan at Lawrence Berkeley National Laboratory, as described in Varadharajan et al.

(2013). Grain size distributions were measured at the Alabama Power Company soils laboratory

in Varnons, Alabama following ASTM method D422 (ASTM, 2007).

4. Results

4.1. Hydrostratigraphy, grain size and mineralogy

The first two sand units encountered consisted of orange and gray, gravel-rich sands,

while the third and lowermost aquifer unit was characterized as gray, well-sorted, fine-grained

sand with trace amounts of silt and clay (Figure 2.5). The lowermost aquifer was bound above

and below by olive green silt- and clay-rich confining to semi-confining units (Figure 2.6). The

Citronelle Formation contained more coarse sand and fine gravel than the target Graham Ferry

Formation. The Graham Ferry, bound above and below by silt- and clay-rich layers, was

composed primarily of well-sorted fine-grained sand, with minor silt and clay.

19

Figure 2.5 Sands and gravels from the Citronelle (a and b) and fine,silty sand from the Graham

Ferry (c)

(a) (b) (c)

20

Figure 2.6. Study site cross-section, illustrating sequence of clay and sand units beneath the test

site.

PW-1 MW-4 MW-3 IW-1 BG-1

Sand and Gravel

Clay

Clay

Sand and Gravel

Silty Fine Sand

Clay

Clayey Sand

Fine Sand

Silt

Clay

0 M

-10 M

-20 M

-30 M

-40 M

-50 M

10 M .

0 M 10 M 20 M 30 M 40 M 50 M 60 M 70 M 80 M 90 M

Test Zone

NW SE

Ele

vation

(Mete

rs M

SL)

Distance (Meters)

A

A’

BG-1

IW-1MW-3

MW-4

PW-1

MW-1

MW-2

N

21

Bulk sample X-ray diffraction (XRD) revealed a mineral assemblage consisting of quartz,

albite, sanidine, pyrite, and illite (Table 2.1). Sandy samples exhibited the lowest cation

exchange capacities, and those containing illite and pyrite exhibited higher cation exchange

capacities. Pyrite was identified in organic-rich and clayey sediments. Scanning electron

microprobe images showed that pyrite framboids were present. Also present were needle-like

growths of what appeared to be gypsum on quartz, although gypsum was not detected with XRD

analysis (Figure 2.7).

Table 2.1 Sediment characteristics

Well Depth (m) CEC

(meq/100g)

Minerals Identified by XRD Notes

PW-1 48.7 1.34 Quartz, Sanidine Sand

MW-4 51.8 1.36 Quartz, Sanidine, Albite, Illite Sand

IW-1 52.1 1.48 Quartz, Sanidine, Albite Sand

MW-2 50.9 5.3 Quartz, Sanidine, Albite, Illite,

Pyrite Organics present

IW-1 46.9 2.13 Albite, Sanidine, Illite Clay above target

zone


Pyrite

Clay above target

zone

BG-1 55.5 5.01 Quartz, Sanidine, Albite, Illite,

Pyrite

Clay below target

zone


Pyrite

Clay below target

zone

22

Figure 2.7 Scanning electron photomicrograph showing (a) quartz and pyrite, (b) pyrite framboid

(magnified from (a)), (c) quartz gypsum and pyrite and (d) gypsum and pyrite (magnified from

square area in (c)).


Slug tests were performed in wells PW-1, MW-1 and MW-2 (Table 2.2).

Using the slug withdrawal data (i.e., water flow from the aquifer toward the well), the average

calculated horizontal hydraulic conductivities were 0.015 and 0.011 cm/sec (42.5 and 31.2

ft/day) using the Hvorslev and Bouwer-Rice solutions, respectively.

Displacement versus time data for both observation wells in the first pumping test agree

with the Theis solution for confined aquifer conditions (Figure 2.8). Well MW-1 data after 2

minutes and all of well PW-1 data fit the Theis solution curve well. Hydraulic conductivity

calculated using the Theis solution for wells PW-1 and MW-1 during the first test were 44.4 and

150x 3,000x

350x 3,000x

(a) (b)

(c) (d)

Pyrite

Quartz

Gypsum

Gypsum

Pyrite

framboid

Quartz

Quartz

Pyrite

23

44.6 ft/day, respectively. Horizontal hydraulic conductivity calculated using the Theis solution

for wells MW-1 and IW-1 during the second test were 40.8 and 41.2 ft/day, respectively (Figure

2.8).

Table 2.2. Well slug test results.

Well Test

Hvorslev (1951)

solution

(cm/sec)/(ft/day)

Bouwer-Rice (1976)

solution

(cm/sec)/(ft/day)

PW-1 Slug in 0.026/73.7 0.018/51.0

Slug out 0.014/39.1 0.009/25.5

MW-1 Slug in 0.005/14.2 0.004/11.3

Slug out 0.015/42.5 0.012/34

MW-2 Slug in 0.007/19.8 0.006/17

Slug out 0.015/39.7 0.011/31.2

Slug in average 0.012/34.0 0.009/25.5

Slug out average 0.015/42.5 0.011/31.2

Displacement versus time data for both observation wells in the first pumping test agree

with the Theis solution for confined aquifer conditions (Figure 2.8). Well MW-1 data after 2

minutes and all of well PW-1 data fit the Theis solution curve well. Hydraulic conductivity

calculated using the Theis solution for wells PW-1 and MW-1 during the first test were 44.4 and

44.6 ft/day, respectively. Horizontal hydraulic conductivity calculated using the Theis solution

for wells MW-1 and IW-1 during the second test were 40.8 and 41.2 ft/day, respectively (Figure

2.8).

24

Figure 2.8. Pumping test results showing displacement versus time curves for PW-1, MW-1, and

IW-1.

4.3. Groundwater chemistry

All chemical data are tabulated in Appendix A, including field measurements (Table A-

1), major and minor cations (Table A-2), anions and alkalinity (Table A-3), trace elements

(Table A-4), dissolved organics (Table A-5) and dissolved gases (Table A-6). This section

summarizes data collected during the baseline sampling period from 2/12/10 to 10/18/11.

0.1 1. 10. 100. 1000. 1.0E+40.001

0.01

0.1

1.

Time (min)

Dis

pla

cem

ent (f

t)

Obs. Wells

TW-1

Aquifer Model

Confined

Solution

Theis

Parameters

T = 816.1 ft2/dayS = 0.0001694Kz/Kr = 0.1b = 20. ft

MW-1

Test 2

Theis solution

T = 816.1 f t2/d

S = 0.0001694

Kh = 40.8 f t/d

0.1 1. 10. 100. 1000. 1.0E+40.001

0.01

0.1

1.

Time (min)

Dis

pla

cem

ent (f

t)Obs. Wells

IW-1

Aquifer Model

Confined

Solution

Theis

Parameters

T = 832.3 ft2/dayS = 0.0001735Kz/Kr = 0.1b = 20. ft

IW-1Test 2

Theis solution

T = 823.3 ft2/d

S = 0.0001735

Kh = 41.2 ft/d

BW-1 Constant Rate

0.01 0.1 1. 10. 100. 1000. 1.0E+40.01

0.1

1.

Time (min)

Dis

pla

cem

ent (f

t)

Obs. Wells

BW-1

Aquifer Model

Confined

Solution

Theis

Parameters

T = 887.2 ft2/dayS = 0.000247Kz/Kr = 0.1b = 20. ft

0.01 0.1 1. 10. 100. 1000. 1.0E+40.01

0.1

1.

Time (min)

Dis

pla

cem

ent (f

t)

Obs. Wells

TW-1

Aquifer Model

Confined

Solution

Theis

Parameters

T = 891.8 ft2/dayS = 0.0002915Kz/Kr = 0.1b = 20. ft

PW-1

Test 1

Theis solution

T = 887.2 f t2/d

S = 0.000247

Kh = 44.4 f t/d

MW-1

Test 1

Theis solution

T = 891.8 f t2/d

S = 0.0002915

Kh = 44.6 f t/d

Dis

pla

ce

me

nt (

ft)

Dis

pla

ce

me

nt (

ft)

Dis

pla

ce

me

nt (

ft)

Dis

pla

ce

me

nt (

ft)

Time (min) Time (min)

Time (min)Time (min)

25

4.3.1. Field parameters

Baseline field parameter data are summarized in Table 2.3. pH was neutral to slightly

alkaline during the baseline test period. Measurements of oxidation-reduction potential (ORP)

and dissolved oxygen suggest that the aquifer was anaerobic. Reducing conditions were

indicated by the persistence of measurable dissolved ferrous iron, ranging from 0.01 to 0.64

mg/L. Conductivity and alkalinity were relatively constant during the study period.

Table 2.3 Summary of field parameter data during baseline sampling

Parameter Unit Minimum Maximum Mean

Temperature °C 22 26 23

El. Conductivity uS/cm 617 692 654

pH s.u. 7.36 8.69 7.89

ORP mV -276 10 -136

Ferrous iron mg/L 0.05 0.64 0.30

Alkalinity mg/L as CaCO3 239 327 297

Dissolved Oxygen mg/L 0.01 0.64 0.21

4.3.2. Major and minor cations and anions

Sodium and bicarbonate ions dominated the relative abundances of cations and anions,

respectively (Table 2.4). Calcium, magnesium, and potassium concentrations were less than 10

mg/L, and mean concentrations were less than 5 mg/L. Barium, strontium, lithium, and

manganese concentrations were all less than 0.1 mg/L. The degree of variability between wells

for major and minor cations is illustrated in Figure 2.9 and Figure 2.10. In general,

concentrations of Mg, K, Fe, Mn and Ba showed greater spatial variability than Ca, Na and Sr.

Nitrate and nitrite were not detected for the majority of sample events, with non-detect rates of

78% and 98%, respectively. Chloride concentrations were relatively stable, averaging 26 mg/L.

26

Sulfate concentrations averaged less than 1 mg/L, and were higher in BG-1 than in other wells

(Figure 2.11).

Table 2.4 Summary of baseline major and minor cation and anion concentrations.

Parameter Unit Minimum Maximum Mean

Ca mg/l 2.0 4.2 2.8

Mg mg/l 0.81 1.90 1.26

Na mg/l 140 190 157

K mg/l 1.80 7.60 3.10

Si mg/l 8.4 13 11.7

Total Fe mg/l 0.05 0.89 0.53

Fe2+

mg/l 0.05 0.64 0.30

Fe3+

mg/l 0* 0.67 0.23

Al ug/l <0.023 0.047 <0.023

Ba mg/l 0.027 0.076 0.056

Sr mg/l 0.075 0.14 0.098

Mn mg/l 0.025 0.10 0.064

Li mg/l 0.008 0.047 0.022

Cl mg/l 21 30 26

HCO3

mg/l 239 326 297

SO4

mg/l <0.015 3.4 0.577

Br mg/l <0.0041 0.5 0.11

F mg/l 0.30 0.60 0.45

NO3 mg/l <0.013 0.034 <0.013

NO2 mg/l <0.013 0.013 <0.013

*Calculated as difference between total Fe and Fe2+

27

Figure 2.9 Spatial variability of Ca, Mg, Na and K during baseline sampling

4.3.3. Trace elements

Table 2.5 summarizes baseline concentrations of trace elements. Silver, As, Be, Co, Cr,

Cu, Hg, Pb, and Tl were not present above method detection limits during the baseline study

period. Molybdenum was the only trace element detected at each sampling event, with a

concentration range of 0.002 to 0.013 mg/L and minor variability between wells (Table A-4).

MW-1 MW-3 MW-2 MW-4 BG-1

Stations

0

1

2

3

4

5

6

7C

a (

mg

/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

0.0

0.4

0.8

1.2

1.6

2.0

Mg

(m

g/l) H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

0

1

2

3

4

5

6

7

8K

(m

g/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

120

130

140

150

160

170

180

190

200

Na

(m

g/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

28

Figure 2.10 Spatial variability of Fe, Ba, Mn and Sr during baseline sampling

4.3.4. Dissolved gases (oxidation-reduction potential, ammonia, ferrous iron, sulfate,

hydrogen sulfide, methane, carbon dioxide)

Methane was detected during each sampling event for all wells at levels ranging from

0.01 to 1.9 mg/L. Ammonia concentrations were consistently detected at values ranging from

0.16 to 0.5 mg/L, averaging 0.34 mg/L. Hydrogen sulfide was detected at concentrations up to

4.8 mg/L, but was generally not present above the method detection limit of 1.1 mg/L.

Laboratory-measured dissolved CO2 concentrations ranged from 9 to 120 mg/L, averaging 72

mg/L. Well MW-1 typically exhibited higher dissolved CO2 concentrations than the other wells,

while wells BG-1 and MW-3 exhibited the lowest dissolved CO2 concentrations


Stations

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9F

e (

mg

/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

0.00

0.02

0.05

0.07

0.10

0.12

Mn

(m

g/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

0.00

0.02

0.05

0.07

0.10

0.12

Ba

(m

g/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.


Stations

0.0

0.1

0.2

0.3

0.4S

r (m

g/l)

H

HH

H

H

H

H

H

HH

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

29

Figure 2.11 Spatial variability of SO4 during baseline sampling

4.3.4. Data correlations

Correlation coefficients (r2) were calculated for data pairs spanning field parameters,

major ions, minor ions and trace elements from all wells. The highest positive correlation was

observed for lithium and potassium (r2 = 0.87). Other data pairs exhibiting positive correlation

(r2 > 0.5) included Ca vs Mg (r

2 = 0.67), Mg vs Mn (r

2 = 0.67), Mn vs Fe (r

2 = 0.71), Ba vs Ca (r

2

= 0.504), Ba vs Mg (r2 = 0.675), Ba vs Mn (r

2 = 0.669), Sr vs Ba (r

2 = 0.594), and Sr vs Ca (r

2 =

0.717). Negatively correlated data pairs (r2 < -0.5) included Fe vs K (r

2 = -0.543), pH vs CO2 (r

2

= -0.636), Li vs CO2 (r2 = -0.607), and K vs CO2 (r

2 = -0.584).


Stations

0

1

2

3

4S

O4

(m

g/l)

H

H

H

H

H

H

H

H

H

H

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

75th Percentile

Median

25th Percentile

95th Percentile

5th Percentile

H

H

Max.

Min.

30

Table 2.5 Summary of trace element data during baseline sampling

Chapter 3 Parameter Units

Chapter 4 Baseline

Range

Chapter 5 Mean

Ag mg/L <0.00025 <0.00025

As mg/L <0.0013 <0.0013

Be mg/L <0.00025 <0.00025

Cd mg/L <0.000095 <0.000095

Co mg/L <0.00015 <0.00015

Cr mg/L <0.0025-0.007 <0.0025

Cu mg/L <0.0011 <0.0011

Hg mg/L <0.00007 <0.00007

Mo mg/L 0.002-0.013 0.005

Ni mg/L <0.002-0.037 0.002

Pb mg/L <0.0002-0.0009 <0.0002

Sb mg/L <0.0023-0.003 <0.0023

Se mg/L <0.001-0.001 <0.001

Tl mg/L <0.0005 <0.0005

Zn mg/L <0.0083-0.028 <0.0083

4.3.5. Data correlations

Data were also investigated for pH-dependence using correlation coefficients.

Potassium and lithium concentrations each exhibited pH-dependence, particularly above pH of

approximately 7.9, with correlation coefficients of 0.61 and 0.62, respectively. No other

parameters exhibited significant pH-dependence (-0.5 > r2 > 0.5).

31

Noticeable differences in the pH, and K and Li concentrations in wells BG-1 and MW-3,

compared to the other wells, created concern that non-representative samples from these two

wells may have resulted from well construction or sampling. After eliminating well MW-3 and

well BG-1 data, no correlations with pH or dissolved CO2 were observed for any parameter, and

the r2 value for the data pair Li vs K decreased from 0.87 to 0.46. The highest correlation from

the edited data pool was between Ca and Sr, with r2 = 0.87. Potassium showed a strengthened

correlation with Ca, Mg, Mn, Ba, and Sr, with r2 > 0.65 for all pairs. In general, the correlations

between major and minor cation data pairs Ca, Mg, K, Na, Sr, Ba, Fe, and Mn were strengthened

in the edited data pool.

4.3.6. Mineral saturation indices

Groundwater saturation indices were calculated for carbonates, sulfate, sulfides,

oxides/oxyhydroxides and silicates using PHREEQC (wateq4f.dat thermodynamic database).

Groundwater saturation indices for sulfates, carbonates and sulfides are illustrated in Figure 2.12.

Groundwater samples were undersaturated with respect to all sulfate minerals, but highly

supersaturated with respect to pyrite and greigite (Fe3S4), and near saturation or slightly

supersaturated with respect to amorphous FeS(am) and mackinawite (FeStet). While the average

saturation index (S.I.) values for all carbonate minerals, except siderite (FeCO3), indicate

undersaturation, the maximum calculated saturation indices for these phases (except strontianite

and witherite) suggest that carbonate equilibrium or precipitation is theoretically possible.

However, with the exceptions of siderite and rhodochrosite, the majority of samples collected

during the baseline period indicate a tendency toward carbonate dissolution (Figure 2.13).

32

Figure 2.12 Groundwater sulfate, carbonate, and sulfide saturation indices box-and-whisker

plots (triangle indicates the average and vertical bars represent maximum and minimum values).

-1.2

-4.1

-7.0

-4.3

-6.7

-5.3

-7.2

-3.5

-6.5

-9.3

-6.8

-14.8

-11.8

-13.7

-2.3

-5.2

-8.0

-5.5

-11.3

-8.6

-10.6

-16.0

-14.0

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

Barite Celestite Epsomite Gypsum Alunite Jarosite-K Jarosite-Na

Satu

rati

on

In

de

x

0.20.1

0.4

-0.4

0.2

0.9

-0.7

-1.9

-1.1-1.2

-2.2

-1.7

-0.5

-0.9

-2.1

-3.2

-0.6-0.8

-1.3 -1.2

-0.1

0.4

-1.6

-2.7

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

Calcite Aragonite Dolomite Magnesite Rhodochrosite Siderite Strontianite Witherite

Satu

rati

on

In

de

x

Sulfates

Carbonates

10.52

1.73

20.65

2.46

8.21

0.03

15.85

0.76

9.89

1.30

19.20

2.03

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

22.0

Pyrite FeS(ppt) Greigite Mackinawite

Satu

rati

on

In

de

x

Sulfides

33

Figure 2.13. Histograms of groundwater carbonate mineral saturation indices.

Of the metal oxides and oxyhydroxides, groundwater samples were undersaturated with

respect to Mn-bearing phases, and supersaturated with respect to Fe-bearing phases. Fe(OH)3(am)

was the closest to equilibrium of the Fe-bearing oxides/oxyhydroxides. Samples were near

equilibrium with boehmite and gibbsite, undersaturated with respect to Al(OH)3(am) and

0%

10%

20%

30%

40%

50%

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70%

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90%

100%

0

5

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30

-1 -0.75 -0.5 -0.25 0 0.25 More

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0%

10%

20%

30%

40%

50%

60%

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100%

0

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-2 -1.5 -1 -0.5 0 0.5 More

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cy

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Cumulative %

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60%

70%

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100%

0

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cy

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Cumulative %

0%

10%

20%

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40%

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60%

70%

80%

90%

100%

0

5

10

15

20

25

30

35

40

45

Fre

qu

en

cy

Bin

Frequency

Cumulative %

CaCO3 CaMg(CO3)2

FeCO3MnCO3

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0

5

10

15

20

25

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qu

en

cy

Bin

Frequency

Cumulative %

SrCO3

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0

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10

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20

25

30

35

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qu

en

cy

Bin

Frequency

Cumulative %

BaCO3

34

supersaturated with respect to diaspore. Silicate mineral saturation indices are shown in Figure

2.14. Of the silicates identified in aquifer sediments by XRD, S.I. values indicate that

groundwater is near chemical equilibrium to slightly supersaturated with respect to illite, while

potassium feldspar and sodium feldspar show a thermodynamic tendency to dissolve (Figure

2.15).

Figure 2.14. Groundwater aluminum, iron, and manganese oxyhydroxide mineral saturation

indices box-and-whisker plots.

-1.5

0.7

2.4

1.2

-2.6

-0.4

1.3

0.1

-2.0

0.2

1.9

0.7

-3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

Al(OH)3(am) Boehmite Diaspore Gibbsite

Satu

rati

on

In

de

x

2.8

19.2

9.0

21.6

1.8

17.1

6.9

19.0

2.3

18.3

8.1

20.4

0.0

5.0

10.0

15.0

20.0

25.0

Fe(OH)3(am) Hematite Maghemite Magnetite

Satu

rati

on

In

de

x

-8.2

-5.6

-2.6

-5.1-6.0

-15.5 -15.2

-6.5 -6.8

-13.6-13.4 -12.9

-5.6 -5.9

-11.6

-18.0

-16.0

-14.0

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

Birnessite Hausmannite Manganite Pyrochroite Pyrolusite

Satu

rati

on

In

de

x

Al-oxyhydroxides

Fe-oxyhydroxides

Mn-oxyhydroxides

35

Figure 2.15. Groundwater silicate mineral saturation indices box-and-whisker plots.

-0.2-1.1

-2.7

-6.7

-3.7

2.31.2

-1.0

-2.2-1.5

-6.3

5.7

-1.2

1.3

-1.1-1.6

-3.1

-14.8

-4.4

-0.4

-9.8-8.9

-4.8

-6.8

-11.6

-1.9

-3.7

-0.2-0.6

-1.3

-2.9

-11.3

-4.2

1.1

-6.1 -6.0

-3.9-4.8

-9.7

1.8

-2.3

0.5

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0Sa

tura

tio

n I

nd

ex

3.9

7.6

0.2

8.3

2.2

4.1

-0.2

-2.9 -2.5

6.6

-4.2

2.2

3.9

1.4

5.4

-0.7

6.5

-0.4

3.4

-1.0

-11.0

-5.6

4.3

-9.1

-5.5

-14.4

2.8

6.4

-0.2

7.5

1.1

3.7

-0.6

-8.1

-4.5

5.5

-7.2

-2.7

-7.5

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0

Satu

rati

on

In

de

x

Silicates (a)

Silicates (b)

36

5. Discussion

5.1. Hydraulic conductivity regional comparison

The range of hydraulic conductivity (Kh) estimates (40-45 ft/day) produced for the study

site are similar to reported median values for the Graham Ferry Formation in Jackson County,

Mississippi, of 50 ft/day. Sumner et al. (1987), in a study simulating effects of groundwater

withdrawals on the Miocene aquifer system in Mississippi, reported model-derived Kh values for

the Graham Ferry aquifer of 30 ft/day, in close agreement with measured values at the study site.

Higher median Kh values in the Graham Ferry aquifer of 102 and 110 ft/day were reported for

Hancock and Harrison Counties, respectively, immediately west of Jackson County. Hydraulic

conductivity measurements reported statewide for the Graham Ferry aquifer range widely from

26 to 350 ft/day (Harvey et al., 1965).

Hydraulic conductivity values for unconsolidated sediments can be estimated based on

grain size distribution (Vukovic and Soro, 1992). When viewed in context of the aquifer

sediment grain size, the measured hydraulic conductivity at the test site falls within the range of

values reported for predominantly medium-grained sand aquifers or mixed sand-and-gravel

aquifers, but above the range expected for fine-grained sands (Figure 2.16), suggesting that a

simplistic estimation of aquifer hydraulic conductivity based on sediment grain size

classification alone is inadequate for this setting.

37

Figure 2.16. Hydraulic conductivity measurements of the current study, for the Graham Ferry

aquifer and other Gulf Coast aquifers, and values estimated for typical sediment grain size

classifications.

In fact, Hazen’s approximation, where K is approximated based on the effective grain

size (d10), significantly underestimates hydraulic conductivity at the test site. Using Hazen’s

approximation:

K = C(d10)2

where K is the hydraulic conductivity (cm/s), C is a coefficient based on grain size and sorting

characteristics, and d10 is the effective grain size (cm), the average hydraulic conductivity for the

site equates to 0.006 cm/s, or 18.1 ft/day (using a C value of 100 for well-sorted medium sand).

One possible explanation for the disagreement between effective grain size and estimated

hydraulic conductivity is the impact of textural maturity, as described by Shepherd (1989).

Shepherd (1989) derived the relationship:

0.01

0.1

1

10

100

1000

Sand and Gravel

Mixes

Coarse Sand Medium Sand Fine Sand Gulf Coast Aquifer

Systems

Graham Ferry

Aquifer Mississippi

Ho

rizo

nta

l Hyd

rau

lic C

on

du

ctiv

ity

(ft/

day

)

Current Study

38

K = Cd50j

where K is estimated hydraulic conductivity, C is a shape factor, d50 is the mean grain size (mm),

and j is an exponent. Values measured at the current study are in closer agreement with

Shepherd’s relationship derived for channel deposits (31.5 ft/day using K = 450*d501.65

), as

opposed to beach deposits (95.3 ft/day using K=1,600*d501.75

). However, the range of hydraulic

conductivity estimates derived using the method of Shepherd (1989), using assumptions of beach

deposits and channel deposits, produces the range of observed measured values in the Graham

Ferry across Mississippi (approximately 30 to 100 ft/day). In fact, Harvey et al. (1965) attributed

major spatial differences in measured transmissibility in the Graham Ferry in Mississippi to

textural variability.

5.2. Regional groundwater quality comparison and historical evolution

MDEQ (2013) reviewed groundwater quality for various potable aquifers in Mississippi,

including thirty measurements of major cation and anion concentrations for the Miocene aquifer

system (summarized in Table 2.6). Minor and trace element data were not reported. The

Miocene aquifer groundwater is characterized by highly variable conductivity measurements,

ranging from 22 to 1,650 mhos/cm. Overall, the major ion concentrations measured for

groundwater at the test site are within the range of values previously reported for the Miocene

aquifer system (MDEQ 2013). Mean values reported for the datasets are not similar, with the

exception of pH and silicon concentration. This similarity is reasonable given that the aquifers

are generally composed of silica sand with minor carbonates, which act to provide solubility

control (silica) or buffer acidity (pH) in the aquifer.

39

Table 2.6. Groundwater major ion concentrations measured in the current study and previously

reported for the Miocene aquifer system in Mississippi (MDEQ 2013).

Parameter Unit Current Study Miocene,

MDEQ (2013)

Range Mean Range Mean

Conductivity mhos/cm 617-692 654 22-1,650 353

pH s.u. 7.36-8.69 7.89 5.6-9.0 7.26

Ca mg/l 2.0-4.2 2.8 0.5-94 10.98

Mg mg/l 0.81-1.9 1.26 0.1-46 4.19

Na mg/l 140-190 157 1.7-380 65

K mg/l 1.8-7.6 3.1 0.5-5.2 1.55

Si mg/l 8.4-13 11.7 4.4-29 11.7

Fe mg/l 0.05-0.89 0.53 0.01-0.35 0.05

Cl mg/l 21-30 26 0.4-380 5.1

HCO3 mg/l 239-326 297 6-564 115

SO4 mg/l <0.008-3.4 0.577 0.2-63 9.6

F mg/l 0.3-0.6 0.45 0.1-1.4 0.2

NO3 mg/l <0.0065-0.034 0.011 0.1-4.2 0.15

At least 5 major geochemical processes are believed to affect water chemistry along the

United States Gulf coast: 1) leaching of soluble salts from the unsaturated zone, 2) alteration of

albite, 3) cation exchange, 4) mixing of water by the vertical flow of water from underlying units

and 5) the dissolution of halite from salt diapirs (Pettijohn, 1996). A viable approach to

interpreting present-day groundwater quality at the test site and in the region is to view the data

in the context of aquifer freshening (Appelo, 1994). As illustrated in Figure 2.17, rainwater is

simulated to infiltrate a biologically active, calcite-containing soil zone and percolate into the

phreatic zone. The originally saline groundwater is freshened by the infiltrating rainwater,

creating a front of freshwater advancement toward the ocean. Major ion concentrations are

modified by simple mixing and chemical reactions. Compositional deviations from simple

mixing must be accounted for by chemical reactions such as cation exchange.

40

Figure 2.17. Conceptual model illustrating aquifer freshening of saline groundwater (X

represents the exchangeable mole fraction).

In order to illustrate that a geochemical process which is thought to be regionally

dominant in determining major ion chemistry is also active at the test site, two modeling

scenarios were simulated. In the simplest case, PHREEQC mixing of rainwater and seawater

results in a much lower predicted groundwater sodium concentration than exists in the present-

day aquifer (Figure 2.18). At the time when the present-day chloride concentration (28 mg/L) is

achieved by simple mixing, the sodium concentration is predicted to be approximately 10 times

lower than the present-day concentration of 150 mg/L. The simple mixing model results in a

deficit of sodium and a surplus of calcium when compared to present-day chemical composition.

Therefore, chemical reactions must play a role in determining both groundwater sodium and

bicarbonate concentrations over time.

Recharge

Rainwater modified by the vadose zoneenvironment

Seawater in equilibrium with theaquifer matrix

WellOcean

2Na-X + Ca2+ = 2Na+ + Ca-X2

41

Figure 2.18. Results of a simple PHREEQC rainwater-saline water mixing model showing

trends in groundwater major ion concentrations over time during aquifer freshening.

PHREEQC simulations were run to evaluate the effects of aquifer freshening (rainwater

equilibrated with vadose zone calcite and atmospheric PCO2) on an aquifer medium with cation

exchange sites originally saturated with seawater. Because it is unlikely that illite was originally

present in the aquifer sediments, the simulation included Ca-montmorillonite, calcite, and

potassium feldspar as present initially, with illite allowed to precipitate as it exceeded saturation.

Under these conditions, both Na+ and HCO3

- concentrations are predicted more accurately using

the cation exchange model than through simple mixing (Figure 2.19). The disagreement

between measured and predicted SO42-

concentrations (i.e., more predicted SO42-

than is actually

present) could be due to microbial sulfate reduction in the aquifer, producing the sulfides

observed through XRD and SEM analyses.

0.1

1

10

100

1000

10000

100000

0 5 10 15 20 25 30 35 40

Dis

solv

ed C

on

cen

trat

ion

(m

g/L

)

Step

Cl

Na

Ca

Mg

HCO3

K

SO4

Cl = 26 mg/L

Present-Day Based on Chloride Concentration

Measured Modeledmg/L mg/L

Na 157 15K 1.5 0.5Ca 1.6 118

Mg 1.2 2HCO3 297 361

SO4 <1 5Cl (fixed) 26 26

42

Figure 2.19. Aquifer freshening trends of groundwater major ion concentrations modeled using

PHREEQC and incorporating ion exhange (Exchangeable mole fraction (X) = 0.03; Ca-

montmorillonite, calcite, and K-feldspar allowed to dissolve and illite allowed to precipitate).

Chowdhury et al. (2006) report supporting evidence that aquifer freshening and cation

exchange play a dominant role in determining major ion composition of the Texas Gulf Coast

Aquifer system. In particular, plots of excess sodium from sources other than halite and excess

calcium and magnesium from sources other than gypsum and carbonate showed nearly perfect

correlations (R2>0.95 for all Texas Gulf Coast Aquifers), and molar ratios of excess sodium

relative to depletions of calcium and magnesium of approximately 2 (Figure 2.20). This ratio is

indicative of an ion exchange reaction where calcium and magnesium are displacing sodium into

solution.

0.1

1

10

100

1000

10000

100000

0 5 10 15 20 25 30 35 40

Dis

solv

ed C

on

cen

trat

ion

(m

g/L

)

Step

Cl

Na

Ca

Mg

HCO3

K

SO4

Cl = 26 mg/L

Present-Day Based on Chloride Concentration

Measured Modeledmg/L mg/L

Na 157 160K 1.5 3.1Ca 1.6 2.8

Mg 1.2 1.2HCO3 297 340

SO4 <1 5Cl (fixed) 26 26

43

Nearly the exact same relationship is observed data reported for the Miocene aquifer system in

Mississippi (MDEQ, 2013), suggesting that aquifer freshening and cation exchange could be

dominant processes affecting major ion water quality not only at the study site, but in sandy

aquifers of the Gulf Coast region.

Figure 2.20 Plot illustrating relationship between excess sodium and depletions in Ca+Mg in the

Miocene aquifer in Mississippi and similarity to the Texas Gulf Coast.

5.3. Groundwater pH and PCO2

Biological processes often produce CO2 as a reaction by-product (Langmuir, 1997)

(Table 2.7). The degree of CO2 supersaturation relative to atmospheric values, or PCO2 groundwater /

PCO2 atmosphere, is a useful indicator parameter to quantify the degree of biological activity

occurring in an aquifer. A ratio of 1 indicates atmospheric equilibrium and values >1 indicate

Miocene in Mississippi:y = -2.111x + 0.1834

R² = 0.8364

-2

0

2

4

6

8

10

12

-5 -4 -3 -2 -1 0 1

Na -

Cl (m

mo

l/L

)

Ca + Mg - SO4 - 0.5*HCO3 (mmol/L)

Chowdhury et al. (2006):y = -1.842x - 0.16 R2 = 0.98

44

CO2 overpressures. It is generally accepted that groundwater and, to a lesser extent, surface

water are potential net sources of CO2 to the atmosphere (Langmuir, 1997).

Table 2.7. Typical CO2-generating reactions in groundwater systems.

Process Reaction

Aerobic respiration and decay 1/6C6H12O6 + O2 CO2 + H2O

Nitrate uptake and reduction NO3- + 2H

+ + 2CH2O NH4

+ + 2CO2 + H2O

Denitrification 5CH2O + 4NO3- + 4H

+ 5CO2 + 2N2 + 7H2O

Sulfate reduction 2CH2O + SO42-

+ H+ 2CO2 + HS

- + 2H2O

Methane fermentation C6H12O6 3CH4 + H2O + CO2

*After Langmuir (1997)

At the test site, the lowest pH values are indicative of aquifer CO2 supersaturation states

of up to 28 times the atmospheric value (Figure 2.21), suggesting that biological activity makes

the aquifer a potential net source of CO2 to the atmosphere. If true, then degassing of CO2

during groundwater sampling (which involves depressurization and possible gas exchange) is a

concern for proper design of an experiment intended to monitor the purposeful introduction of

CO2 to the aquifer. Figure 2.22 illustrates the statistical distribution of pH measurements taken

during the baseline study period. The presence of the tail on the right side of the statistical

distribution of pH measurements may indicate the relative ease of CO2 degassing and subsequent

pH rise (producing a right tail). In contrast, a mechanism to produce lower pH results than in situ

conditions is lacking, explaining the absence of a left-side tail.

45

Figure 2.21. Relationship between pH and degree of CO2 supersaturation in groundwater,

showing a higher degree of supersaturation at lower pH.

Figure 2.22. Histogram of groundwater pH measurements during the baseline study period.

7.2

7.4

7.6

7.8

8.0

8.2

8.4

8.6

8.8

0 5 10 15 20 25 30

pH

PCO2 groundwater / PCO2 atmosphere

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0

5

10

15

20

25

30

7 7.25 7.5 7.75 8 8.25 8.5 8.75 9 More

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qu

en

cy

Bin

Frequency

Cumulative %

46

5.4. Groundwater redox conditions and Eh

The persistent detection of measureable methane and ammonia, and the occasional

detection of hydrogen sulfide in groundwater samples, suggest a chemically reducing

environment in the aquifer. Under equilibrium conditions, methanogenesis occurs after a

sequence of biologically-driven redox reactions. When an organic carbon source is present in

groundwater, aerobic decay will proceed until all dissolved oxygen is depleted. After available

oxygen is consumed, anaerobic processes (reduction of MnO2 to Mn2+

, NO3- reduction to NO2,

reduction of Fe3+

to Fe2+

, reduction of SO42-

to HS-, and reduction of HCO3

- to CH4) dominate.

These reactions will generally proceed in the order as listed above, as the redox potential

becomes more negative, but will only occur in the presence of solute sources to the groundwater,

such as minerals, gases or anthropogenic inputs. For example, methanogenesis may occur in the

absence of SO42-

reduction, if there is no source of dissolved SO42-

to the groundwater (Appelo

and Postma, 1999).

The presence of dissolved ferric iron in a methanogenic environment, in addition to other

measurements, suggests a condition of redox disequilibrium. To be at equilibrium, a system

producing methane gas would have progressed through complete reduction of ferric to ferrous

iron, either in dissolved or mineralized form. Comparing all measured Eh values to those

calculated using redox pairs for Fe, S, and C suggests that the higher measured Eh values may be

reflective of the Fe2+

/Fe(OH)3 redox couple while the lower measured values may be reflective

of the SO42-

/FeS2 redox couple (Figure 2.23).

47

Figure 2.23. Relationship between measured Eh values and Eh calculated using measured

concentrations of redox pairs.

This redox disequilibrium could be an artifact of sampling and analytical procedures,

including the measurement of Eh itself. Field measurements can represent mixed potentials of

various active redox couples (Langmuir, 1997; US EPA, 2002), which may result when a species

is present in too low a concentration to create a significant current flow at the measuring

electrode. Langmuir (1997) asserts that thermodynamically-meaningful Eh measurements may

be possible in groundwater containing elevated concentrations of dissolved Fe, Mn, and H2S, but

are often not possible in groundwater where C, N, O, H, and oxidized S are the dominant redox-

sensitive elements.

A sequence of chemical reactions through time may explain the current state of redox

disequilibrium (Figure 2.24). The sequence assumes that the Graham Ferry sediments were

-400

-350

-300

-250

-200

-150

-100

-50

0

50

-400 -350 -300 -250 -200 -150 -100 -50 0 50

Cal

cula

ted

Eh

(m

V)

Measured Eh (mV)

HCO3-/CH4(aq) SO42-/FeS2 Fe(OH)3/Fe2

48

originally deposited in a marine or nearshore environment (Stage 1), and were primarily

composed of organic material, quartz, feldspars, clays, and calcite. Extended periods of burial

and atmospheric isolation (Stage 2) led to anoxic conditions, reduction of dissolved iron and

sulfate, and subsequent precipitation of FeS(m). A period of atmospheric exposure (Stage 3),

possibly related to sea level fall, led to sulfide oxidation, iron oxyhydroxide precipitation,

gypsum precipitation, and calcite dissolution. Incomplete oxidation of ferrous iron could have

resulted in the precipitation of siderite during this stage. Resubmergence of the sediments (Stage

4), potentially due to sea level rise, isolated this mineral assemblage under anoxic conditions,

leading to another phase of sulfide (possibly pyrite) precipitation. The net reaction for the

process during exposure and oxidation is:

(4) FeS2(cry) + 3.5O2 + CaCO3 + Fe2+

+ 3H2O = FeCO3 +

CaSO4:2H2O + Fe(OH)3(s) + SO42-

+ 5H+ + e

-

Groundwater saturation indices suggest thermodynamic equilibrium with FeS, rather than

crystalline FeS2, although pyrite was detected with XRD. Groundwater is highly supersaturated

with respect to pyrite, suggesting that pyrite may be currently forming from amorphous sulfides.

In summary, the groundwater does not appear to be in redox equilibrium with the aquifer

mineralogy, suggesting a dynamic chemical system. The interpretation provided, however,

allows for a phased progression toward present-day conditions which relies on the assumption

that sediments were deposited, exposed to the atmosphere, and then reburied and isolated from

the atmosphere. This type of sequence can occur in a transgressive-regressive sedimentation

cycle which would be typical of coastal environments during the Miocene-Pliocene.

49

Figure 2.24. Possible stages of geochemical evolution of the study site aquifer over geologic

time (FeS(m) = mackinawite).

6. Conclusions

This chapter reviewed the results of a baseline aquifer testing program conducted at the

Plant Daniel study site in Pascagoula, MS. The purpose of the testing program was to produce

physical and chemical data necessary to design, implement and interpret a controlled-release

field test evaluating impacts of elevated PCO2 on aquifer water quality at the Plant Daniel site.

Stage 1 –Deposition Stage 2 – Burial/Anoxic

Stage 3 – Exposure/Oxidation Stage 4 – Reburial/Anoxic

Calcite

Quartz/Feldspars/Clays

FeS

Calcite

Quartz/Feldspars/Clays

CaCO3 + H+ = Ca2+ + HCO3-

FeS(m) + 3.5 O2 + H2O = Fe2+ + SO42- + 2 H+

Quartz/Feldspars/Clays Quartz/Feldspars/Clays

Ca2+ + SO42- + 2H2O = CaSO4:2H2O

Gypsum

Calcite?

FeS FeS

FeS2

Calcite?

Deposits primarily calcite,quartz, feldspars, clays

Fe2+ + HS- = FeS(m) + H+

Fe2+ + CO32-= FeCO3

Siderite

Gypsum

Siderite

Fe2+ + 2HS- = FeS2 + 2H+

50

Aquifer testing revealed hydraulic conductivity values that are typical for the Mississippi Gulf

Coast and provide the necessary data for flow modeling at the site. PHREEQC simulations

indicate that ion exchange reactions are important for understanding the evolution of dissolved

major ion composition of the site groundwater over geologic time and the possible anthropogenic

impacts from intrusion of CO2. The aquifer is chemically reducing, but due to stages of exposure

and reburial over time, measurements of dissolved redox indicators and aquifer mineralogy most

likely represent a state of redox disequilibrium. The aquifer media contains pyrite and clay

minerals, which are known to be susceptible to dissolution under acidic conditions. These

dissolution reactions are likely to promote ion exchange reactions in the event of acidification

due to elevated CO2. Due to similarities in the evolution of Gulf Coast aquifers over time, the

results of this particular study are believed to be relevant to other sites in the United States Gulf

Coast where opportunities exist for geologic sequestration of CO2.

51

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Appelo, C.A.J. and D. Postma, 1999. Geochemistry, groundwater and pollution. A.A. Balkema

Publishers, Rotterdam, Netherlands. 536 p.

Appelo, C.A.J., 1994. Cation and proton exchange, pH variations, and carbonate reactions in a

freshening aquifer. Water Resources Research, Vol. 30. No. 10, pp. 2793-2805.

American Public Heath Association (APHA), 2012. Standard methods for the examination of

water and wastewater, 22nd

Edition. 724 p. ISBN 0875530133.

ASTM, 2007. ASTM D422-63. Standard Test Method for Particle-Size Analysis of Soils, ASTM

International, West Conshohocken, PA.

Bouwer, H. and Rice, R.C., 1976. A slug test method for determining hydraulic conductivity of

unconfined aquifers with completely or partially penetrating wells, Water Resources

Research, vol. 12, no. 3, pp. 423-428.

Chowdhury. A.H, Boghici, R., and Hopkins, J., 2006. Hydrogeochemistry, Salinity Distribution,

and Trace Constituents: Implications for Salinity Sources, Geochemical Evolution, and Flow

Systems Characterization, Gulf Coast Aquifer, Texas. In Aquifers of the Gulf Coast of Texas.

Texas Water Development Board 365. February, 2006.

Harvey, E.J., H.G. Golden and H.G. Jeffery, 1965. Water Resources of the Pascagoula Area

Mississippi. United States Geological Survey Water-Supply Paper 1763. 144 p.

Hvorslev, M.J., 1951. Time Lag and Soil Permeability in Ground-Water Observations, Bull. No.

36, Waterways Experimental. Station Corps of Engineers, U.S. Army, Vicksburg,

Mississippi, pp. 1-50.

HydroSOLVE, Inc., 2006. AQTESOLV Version 4.0 Professional. HydroSOLVE, Inc. Reston,

Virginia.

Langmuir, D., 1997. Aqueous Environmental Geochemistry. Prentice-Hall, NJ. 600 p.

MCAWW, 1983. Methods for Chemical Analysis of Water and Wastes. EPA-600/4-79-020.

March 1983 and subsequent revisions.

MDEQ, 2000. Ground-water study of historical water-level and water-quality data in Jackson

County, Mississippi. Open-file report 99-102. May 1999. Revised February 2000.

MDEQ, 2013. State of Mississippi Groundwater Quality Assessment. Available online at

https://www.deq.state.ms.us/mdeq.nsf/pdf/GPB_MSGroundwaterQualityAssessment305

b2013/$FILE/305b_2013.pdf?OpenElement.

52

Pettijohn, R.A., 1996. Geochemistry of ground-water in the Gulf Coast aquifer systems, south-

central United States: U.S. Geological Survey Water-Resources Investigations Report 96-

4107,158 p.

SECARB, 2008. SECARB Partners Monthly Update. November 2008. Accessed on-line

November 18, 2013. http://www.secarbon.org/files/2008-11-newsletter.pdf

Shepard, R.G.,1989. Correlations of permeability and grain size. Ground Water, Vol. 27, No. 5,

pp. 633-638.

Sumner, D.M., B. E. Wasson, and S.J. Kalkhoff, 1987. Geohydrology and simulated effects of

withdrawals on the Miocene aquifer system in the Mississippi Gulf Coast area. United

States Geological Survey Water Resources Investigations Report 87-4172.

Trautz, R.C., J.D. Pugh, C. Varadharajan, L. Zheng, M. Bianchi, P. S. Nico, N. F. Spycher, D. L.

Newell, R. A. Esposito, Y. Wu, B. Dafflon, S. S. Hubbard, and J. T. Birkholzer, 2013.

Effect of Dissolved CO2 on a Shallow Groundwater System: A Controlled Release Field

Experiment. Environmental Science and Technology. 47, 298−30

TestAmerica, 2014. TestAmerica, Inc. Standard Operating Procedure, VFA.

UA EPA, 2004. EPA RSKSOP-175 Sample Prep And Calculations For Dissolved Gas Analysis

In Water Samples Using A GC Headspace Equilibration Technique, rev 2, pp. 14.

US EPA, 1974. EPA Method 364.5 Phosphorous, Total (Colorimetric, Automated, Block

Digester AA II), pp. 5.

US EPA, 1994. Methods for the determination of metals in environmental samples. Supplement

I. EPA-600/R-94/111. May 1994.

US EPA, 1994. EPA Method 7470A. Mercury in liquid waste (manual cold-vapor technique). 6

pp.

US EPA, 1996. Low stress (low flow) purging and sampling procedure for the collection of

groundwater samples from monitoring wells. EQASOP-GW 001. Revised 2010.

US EPA, 2002. Workshop on monitoring oxidation-reduction processes for ground-water

restoration. EPA/600/R-02/002. January 2002.





19. pp. 183-211.

Vukovic, M. and A. Soro, 1992. Determination of hydraulic conductivity of porous media from

grain-size composition. Water Resources Publications, Littleton, Colorado, 83 p.

http://www.secarbon.org/files/2008-11-newsletter.pdf

53

Chapter 3

DESIGN AND IMPLEMENTATION OF A FIELD EXPERIMENT EVALUATING IMPACTS

OF CO2 LEAKAGE INTO A CONFINED AQUIFER

Abstract

Geologic carbon sequestration operated at full-scale will require extensive performance

monitoring, including potable groundwater monitoring. However, researchers and regulators do

not fully understand what impact elevated CO2 levels would have on groundwater quality in the

event that CO2 should leak into an overlying aquifer. One way to understand the impacts of CO2

leakage is to perform a field simulation of the leakage scenario and measure the impacts. The

critical aspects of the design and implementation are the ability to control experimental

conditions in the field (e.g., pressure, temperature, redox) and be able to detect responses to the

disturbance (e.g., hydraulic control, downhole pH, conductivity) with enough confidence to

support conclusions and modeled predictions related to CO2-induced groundwater quality

impacts (e.g., trace element mobilization). This study presents the design and implementation of

a closed loop pumping and injection system designed to simulate CO2 leakage into a test site

aquifer. Process monitoring results indicated that the test was performed with minimal variation

in key process parameters, including temperature, pressure and injectate pH. In situ

instrumentation deployed in monitoring wells allowed continuous readings of groundwater pH

and conductivity, which were critical parameters for evaluating the aquifer response to

carbonation and acidification. Successful modeling simulation of the pH response using results

from the aquifer testing program suggested that the test was implemented and monitored

54

appropriately and that that future data interpretations and modeling of the field experiment were

not compromised by test design.

1. Introduction

Geologic carbon sequestration operated at full-scale will require extensive performance

monitoring, including potable groundwater monitoring (EPA, 2010). However, researchers and

regulators currently do not fully understand what impact elevated CO2 levels would have on

groundwater quality in the event that CO2 should leak into an overlying aquifer. Furthermore,

coupled geochemical and transport models which have been verified by field data are limited,

making predictive modeling of CO2 impacts highly uncertain. This knowledge gap ultimately

makes it difficult to develop a truly effective aquifer monitoring plan.

To address this knowledge gap, the Electric Power Research Institute (EPRI) funded two

field experiments evaluating the impacts of PCO2 on aquifer water quality. EPRI (2008) injected

CO2 into a shallow, unconfined aquifer system in Montana and observed a decrease in

groundwater pH – from pH 7 to 6 – and increased bicarbonate, calcium, and magnesium

concentrations. The study was ultimately difficult to model with coupled flow and transport

codes, due to the occurrence of gas exsolution from the aquifer into the vadose zone and

subsequent redissolution of CO2 into the water table further down-gradient. Recognizing these

limitations, a second field experiment, the subject of this chapter, was conducted in a more

controlled hydrogeologic setting, in an effort to simulate a leak of CO2 into a shallow aquifer and

observe the effects on water quality. To accomplish this, thorough aquifer characterization and

planning were conducted to ensure that test results and interpretive modeling efforts were highly

defensible.

55

The purpose of this chapter is to describe the design and implementation process for

simulating a leakage of CO2 into the second EPRI test site aquifer in Pascagoula, MS. The

critical aspects of the design and implementation are the ability to control experimental

conditions in the field (e.g., pressure, temperature, redox) and detect responses to the disturbance

(e.g., hydraulic control, downhole pH, conductivity) with enough confidence to support

conclusions and modeled predictions related to CO2-induced groundwater quality impacts (e.g.,

trace element mobilization). Data from the above-ground process monitoring instrumentation

and monitoring wells are provided as a means to assess the project design success. It is expected

that the methodology described will be useful to other researchers planning to implement similar

evaluations at potential CO2 sequestration sites.

2. Methods

2.1. Well layout

Results of the 2010 hydrogeologic investigation (Chapter 2) were used to develop a

conceptual model of the test site, upon which relatively simple flow and transport models were

based (Trautz et al., 2013). These preliminary models described in Trautz et al. (2013) were used

to design the final well field (Figure 3.1), including the distance between wells and the final

injection and pumping rates (Table 3.1). A submersible pump was installed in well PW-1, and

designed to produce a continuous pumping rate of 22.7 liters per minutes (L/m). This was the

pumping rate determined that would produce a small hydraulic gradient between the injection

and observation wells, allowing and balance between timely execution of the test and minimizing

the velocity of the injected water so that mineral reactions could occur. The hydraulic gradient

56

between the two wells was increased slightly by pumping 22.7 L/m from well PW-1, discarding

17 L/m of groundwater to surface runoff, and supplying 5.7 L/m to the carbonation unit.

Figure 3.1. Well field layout.

Table 3.1. Well spacing distances and injection rates.

Description Well Designation Distance from

Well IW-1 (m)

Average Injection (+),

Withdrawal (-) Rates

(L/min)

Injection Well IW-1 0 +5.7

Monitoring Wells

MW-1 16.3 --

MW-2 12.8 --

MW-3 4.6 --

MW-4 20.0 --

Background Well BG-1 21.2 --

Pumping Well PW-1 63.4 -22.7

BG-1

IW-1MW-3

MW-4

PW-1

MW-1

MW-2

Background

Monitoring Well

Pumping Well

Injection

Well

Downgradient

Monitoring Wells

15 ftN

57

2.2. Pumping, piping, and carbonation system

The fluid delivery system was a critical component of the experiment that allowed

carbonated groundwater to be injected under pressure into the test interval at a depth of 46.9 to

54.6 m. The piping, pumping, and carbonation system was designed to ensure that line

pressurization and temperature would be maintained as close to aquifer conditions as feasible

during the test (Figure 3.2). A submersible Grundfos™ pump was installed in PW-1, and a

booster pump was installed at the ground surface at well PW-1. Groundwater was pumped from

the aquifer at the rate of 18.9 to 22.7 L/min from well PW-1. Approximately two-thirds of the

clean groundwater (17 L/m) was discharged to a surface water drain and the remaining one-third,

or 5.7 L/min, was pumped to the carbonation unit. The forced gradient between wells PW-1 and

IW-1 was used to control the shape and direction of the dissolved CO2 plume, allowing

carbonated groundwater to be drawn across the intervening monitoring wells where groundwater

samples were collected for further analysis. The temperature of the groundwater withdrawn

from the confined aquifer was maintained by using thermal insulation around all process piping.

The thermal insulation was wrapped in reflective tape so that heating from solar radiation was

minimized. A cartridge filter was installed between the supply pump and the carbonation unit to

remove any sediment from the groundwater before it entered the carbonation unit (Figure 3.3).

58

Figure 3.2 Site cross-section illustrating the injectate fluid delivery system.

The carbonation unit consisted of a contact membrane with food-grade CO2 gas

contacting one side of the membrane and untreated groundwater flowing past the other side. The

CO2 gas was sourced from a liquid CO2 storage tank equipped with an evaporator (Figure 3.3).

The desired amount of CO2 to be dissolved into the aquifer is that which would occur if a bubble

of CO2 were to exist at the aquifer depth and pressure, as represented by the height of the water

column above the top of the aquifer in the monitoring wells (Table 3.2).

PW-1 MW-4 MW-3 IW-1 BG-1

Sand and Gravel

Clay

Clay

Sand and Gravel

Clay

Clayey Sand

Fine Sand

Silt

Clay

0 M

-10 M

-20 M

-30 M

-40 M

-50 M

10 M .

0 M 10 M 20 M 30 M 40 M 50 M 60 M 70 M 80 M 90 M

Test Zone

Ele

vation

(Mete

rs M

SL)

Distance (Meters)

Inflatable

packer

Submersible

Pump (22.7 L/m)

Non-carbonated H2O

Insulated piping

17 L/m

5.7 L/m

Carbonated

H2O at 5.7 L/m

Carbonation

unit

59

Figure 3.3. Carbonation and injection system photograph.

Table 3.2. Aquifer properties and water column pressures.

Well

Aquifer

Bottom

(m)

Aquifer

Top (m)

Aquifer

Thickness

(m)

Depth to

Water

(m)

Water Column

above Aquifer

Bottom (m)

Water Column

above Aquifer

Top (m)

IW-1 54.6 47.5 7.0 9.2 45.4 38.3

PW-1 52.7 47.2 5.5 9.4 43.4 37.9

MW-1 52.7 46.9 5.8 9.2 43.5 37.7

MW-2 54.3 47.9 6.4 9.1 45.1 38.7

MW-3 54.0 47.2 6.7 9.2 44.7 38.0

MW-4 54.0 47.9 6.1 9.3 44.6 38.6

BG-1 54.3 47.5 6.7 9.0 45.2 38.5

Average 53.6 47.5 6.1 9.2 44.6 38.2

psi 63.3 54.33

bar 4.36 3.74

Depths reported in meters below ground surface; 1.42 psi per meter of water; 1 bar = 14.5038

psi; T = 22 ºC

60

The on-demand gas delivery system supplied CO2 to the carbonation unit at 3.3 to 4 bars

pressure, while a slightly lower groundwater pressure was maintained on the “wet” side of the

membrane. This allowed gas to diffuse across the membrane and saturate the groundwater with a

corresponding CO2 concentration around 0.15 molal (~6,600 mg/L as CO2). The process was

expected to reduce the pH of the pumped groundwater from 7.5 to 5.0 units, producing a strong

input and detection signal for the injection experiment.

An additional vent valve after the membrane module was used to ensure that there was no

excess CO2 in the groundwater. Water pressure, temperature, pH, and flow rate were monitored

continuously both upstream and downstream of the carbonation unit (Figure 3.3). Meters and

transmitters were used to communicate data in real-time, accessible from a local internetwork

connection. The meters were designed for process applications and to be removable for

calibration purposes. Interruptions to flow or carbonation effectiveness were diagnosed from a

remote location.

2.3. Downhole pH and conductivity monitoring

Submersible probes with onboard memory were deployed in the monitoring wells to

measure groundwater temperature, pH, electrical conductivity, and oxidation reduction potential

(ORP). These data provide a long-term record of groundwater quality spanning nearly a year,

with a sampling frequency of one measurement every 2-3 hours. The nearly continuous

electronic data set compliments the individual data points for pH, electrical conductance, and

ORP collected manually during the test period.

The monitoring wells were sealed to prevent cross-contamination by atmospheric transfer

and groundwater was sampled using dedicated bladder pumps installed in each well (Figure 3.4).

61

Figure 3.4 Picture showing dedicated bladder pump and well completion.

Following low-flow sampling procedures (US EPA, 1996), groundwater was purged at a low rate

of 0.6 L/min before samples were collected using a technique that reduced outgassing of CO2

from the samples. The water was pumped from the well to the surface through a sampling tube

connected to an in-line flow-through cell where measurements of pH, dissolved oxygen,

conductivity, temperature, and oxidation-reduction-potential were recorded using a

multiparameter probe. When these parameters stabilized, samples were collected upstream of the

flow-through cell into appropriate preserved sample containers. The downstream end of the

flow-through cell was connected to a pressure regulator such that the groundwater samples could

be collected against a back-pressure of 1-2 bars to minimize exsolution of dissolved gases

(Figure 3.5).

62

Figure 3.5 Schematic showing the pressurized monitoring well sampling system.

3. Results

3.1. Process temperature, pressure, and pH

Groundwater pumped from well PW-1 exhibited pH values ranging from 7.21 to 7.83,

averaging 7.52 prior to carbonation (August 12, 2011 to October 18, 2011) (Figure 3.6). Inlet

water temperature during the entire test period fluctuated between 18.4 to 28.6 ºC, and averaged

21.8 ºC. Outlet temperature was slightly higher than inlet temperature during the test period,

ranging from 18.5 to 29.5 ºC, and averaging 22.6 ºC (Figure 3.7). Inlet and outlet pressure

remained fairly steady throughout the test, predominantly ranging between 46 and 50 psi. A

growing differential between inlet and outlet pressure appeared to occur as the study progressed

(Figure 3.8).

63

Figure 3.6. Injectate water pH during the test period, showing pre- and postcarbonation pH.

Figure 3.7. Inlet and outlet water temperature during the test period.

3.00

3.50

4.00

4.50

5.00

5.50

6.00

6.50

7.00

7.50

8.00

7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12

Inje

ctat

e p

H (

s.u

.)

Date

15

17

19

21

23

25

27

29

7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12

Tem

per

atu

re (

celc

ius)

Date

Outlet temperature Inlet temperature

64

Figure 3.8. Inlet and outlet water pressure during the test period.

3.2. Groundwater levels and hydraulic control

Injectate flow remained fairly consistent throughout the test period, averaging

approximately 1.5 gpm (Figure 3.9). Water levels responded rapidly to the beginning of

pumping (dynamic baseline period) and to the end of pumping (end CO2) (Figure 3.10). During

the test period, groundwater elevations were consistently highest at well MW-3 and lowest at

well MW-4, indicating flow toward well MW-4 from the injection well. Overall, the test was not

disturbed by any significant fluctuations in water levels, with the exception of a spike in water

levels in February 2012. The calculated hydraulic gradient between wells MW-3 and MW-4 also

remained fairly consistent throughout the test period, with the exception of during the period of

increased injectate flow (Figure 3.11).

45

46

47

48

49

50

51

52

53

7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12

Pre

ssu

re (

PSI

)

Date

Outlet pressure Inlet pressure

65

Figure 3.9. Injectate water flow rate measured during the test period.

Figure 3.10. Potentiometric groundwater elevations in all monitoring wells during the test period.

0.00

0.50

1.00

1.50

2.00

2.50

3.00

7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12

Inje

ctat

e fl

ow

rat

e (g

pm

)

Date

-2.00

-1.80

-1.60

-1.40

-1.20

-1.00

-0.80

-0.60

-0.40

-0.20

0.00

8/10/10 11/18/10 2/26/11 6/6/11 9/14/11 12/23/11 4/1/12 7/10/12 10/18/12 1/26/13

Wat

er

Leve

ls (

m M

SL)

Date

MW-1 MW-2 MW-3 MW-4 BG-1 Dynamic Baseline Start CO2 End CO2

66

Figure 3.11. Approximate hydraulic gradient and injectate flow rate during the test period.

3.3. Groundwater pH and conductivity

Groundwater pH values in down-gradient wells showed sharp declines to levels similar to

the upper range of injectate pH over time, approximately 5.25 s.u. (Figure 3.12). The apparent

arrival of CO2 at well MW-3 occurred 10 days after initiation of injectate carbonation, and

similar downward pH trends followed in wells MW-2, MW-1, and MW-4. The lowest pH values

measured in wells MW-1 and MW-4 after CO2 breakthrough were higher than the injectate pH.

These wells were located furthest down-gradient from well IW-1 and the experiment was

terminated upon indication that the front had arrived at well MW-4 (157 days after injection).

0.0

0.5

1.0

1.5

2.0

2.5

3.0

-0.004

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12

Inje

ctat

e F

low

(gp

m)

Hyd

rau

lic G

rad

ien

t (m

/m)

Date

Hydraulic Gradient Dynamic Baseline Start CO2 End CO2 Flow

67

Figure 3.12. Downhole groundwater pH measurements during the test period.

After initiating carbonation, groundwater conductivity levels rose sharply to a peak

nearly twice the baseline level in well MW-3, but then decreased to near-baseline levels (Figure

3.13). Wells MW-2, MW-1, and MW-4 also exhibited conductivity increases, followed by

declines, until the experiment was terminated. After CO2 injection ceased, groundwater

conductivity levels began to rise again in wells MW-2 and MW-3.

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

6/6/11 7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12 7/10/12 8/29/12

pH

Date

IW-1 MW-1 MW-2 MW-3 MW-4

Start Injection 10/18/11

Baseline pHrange

Injectate pHrange

Stop Injection 3/23/12

10 days 71 days 108 days 157 daysCO2 arri val times:

68

Figure 3.13. Downhole groundwater conductivity measurements during the test period.

3.4. Downhole versus surface groundwater pH measurements

Groundwater pH measurements conducted at the surface using the backpressure sampling

system were comparable to those made in downhole measurements (Figure 3.14 to Figure 3.17).

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

6/6/11 7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12 7/10/12 8/29/12

Spe

cifi

c C

on

du

ctan

ce (m

s/cm

)

Date

MW-1 MW-2 MW-3 MW-4

Start Injection 10/18/11

Stop Injection 3/23/12

69

Figure 3.14. Downhole and surface pH measurements for well MW-1 groundwater.


5.00

5.50

6.00

6.50

7.00

7.50

8.00

8.50

7/6/2009 1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012 10/18/2012 5/6/2013 11/22/2013

pH

Date

MW-1 surface pH MW-1 downhole pH

4.50

5.00

5.50

6.00

6.50

7.00

7.50

8.00

8.50

7/6/2009 1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012 10/18/2012 5/6/2013 11/22/2013

pH

Date


70



4.00

5.00

6.00

7.00

8.00

9.00

10.00

11.00

1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012 10/18/2012 5/6/2013 11/22/2013

pH

Date


6.00

6.50

7.00

7.50

8.00

8.50

9.00

1/22/2010 8/10/2010 2/26/2011 9/14/2011 4/1/2012 10/18/2012 5/6/2013 11/22/2013

pH

Date


71

4. Discussion

4.1. Leakage simulation

The critical factors affecting the successful simulation of a CO2 leakage scenario are: 1)

ability to simulate a CO2 gas bubble in equilibrium with aquifer water at the appropriate

temperature and pressure, and 2) ability to detect a response to the disturbance with confidence.

The pH measurements of the injectate indicated that adequate carbonation was achieved

during the test. Dissolution of CO2(g) in water is described as:

(5) CO2(g) + H2O = H2CO3o

where H2CO3o is the combination of true dissolved H2CO3

* and CO2(aq), and the contribution of

H2CO3* to H2CO3

o is less than 0.3%. Under ideal conditions the dissolution of CO2(g) in water is

governed by Henry’s Law, which states that at a given temperature, the solubility of a gas in

water is proportional to the partial pressure of the gas. For CO2, the Henry’s Law equation is

described as:

(6) KCO2 (M/bar) = [CO2(aq)]/PCO2

and the value of KCO2 can vary with temperature. H2CO3o will undergo two dissociation steps,

written as:

(7) H2CO3o = H

+ + HCO3

-

where the equilibrium expression is:

(8) K1 = [H+][ HCO3

-]/[ H2CO3

o] = 10

-6.35

and:

(9) HCO3- = H

+ + CO3

2-

where the equilibrium expression is:

(10) K2 = [H+][CO3

2-]/[ HCO3

-] = 10

-10.33.

72

The pH of the water in equilibrium with CO2(g) can be derived from the above equations as:

(11) [H+] = (KCO2*K1*P CO2)/[ HCO3

-]

A titration model simulating incremental additions of CO2(g) to the average aquifer water

composition (reported in Chapter 2) was conducted using PHREEQC (Parkhurst and Appello,

2013). The model results showed that saturating the solution with CO2 at a PCO2 of 4 bars,

resulted in a pH drop from 7.7 to 4.97, and a total dissolved CO2 concentration of 6,050 mg/kg

(Figure 3.18).

Figure 3.18. Relationship between pH and dissolved CO2 to PCO2.

The average surface injection pressure was 3.3 bar (slightly below the calculated aquifer pressure

of 3.74 bar), which should have produced an injectate pH of approximately 5 s.u. The average

injectate pH during the test period was 4.99 s.u., indicating that the injectate contained a strong

pH signal for detecting impacts in downgradient monitoring wells. Results suggest that the CO2

leakage scenario was adequately simulated.

0

2000

4000

6000

8000

10000

12000

14000

16000

4.00

4.50

5.00

5.50

6.00

6.50

7.00

7.50

8.00

0 1 2 3 4 5 6

mg

CO

2/

kg

H2O

pH

PCO2 (bar)

pH mg CO2 / kg H2O

73

4.2. Injectate plume detection (pH and conductivity)

The second critical factor for successful field demonstration was the ability to detect the

disturbance created by the injection. Due to the volatility of gas phases and resulting difficulty

obtaining accurate sampling results, it was important to test the applicability of a backpressured

sampling system and compare results to downhole measurements. Results of the field test

showed that pH measurements conducted at the surface under a backpressure were successful

and compared well to downhole measurements, with few exceptions. There are advantages and

disadvantages to both approaches. Downhole probes provide high-resolution data at relatively

low cost, compared to using field labor on a very frequent basis. Multiple measurements can be

made simultaneously and data can be transmitted to remote access locations for project

monitoring. A disadvantage to downhole measurements is that they most often rely on batteries

and can drift out of calibration range or stop working, if left unattended. The advantage of

surface sampling, if conducted properly, is that the equipment is always calibrated and accurate

and can be linked directly to measured concentrations of other analytes in the sample at the time

of collection. The best way to plan a monitoring program will be based on site-specific

considerations and budgetary constraints. It is suggested that a combination of downhole and

pressurized surface measurements, such as was used in this study, be used to determine changes

in groundwater pH over time. Groundwater pH measurements taken under ambient pressure

conditions should be avoided.

4.3. Modeled downhole pH response

74

The pH response in well MW-3 was modeled using PHREEQC 1-D transport modeling.

Conceptually, the model was a 1-D column consisting of 10 cells, each 0.46 meters in length

between wells IW-1 and MW-3 (Figure 3.19).

Figure 3.19. Representation of the PHREEQC 1-D column transport model.

Dispersivity was set to 0.1 m (as determined by Trautz et al., 2013) and an average velocity was

computed as 0.46 m/d, based upon a previously conducted argon tracer test (Trautz et al., 2013).

Only the aqueous dissolution of CO2(g) and carbonate speciation were considered in the

geochemical reactions. No solid phases, exchange sites, or surface sorption sites were included.

As shown in Figure 3.20, the actual pH response of groundwater in well MW-3 was very

similar to that modeled with PHREEQC using no solid phase buffering reactions such as ion

exchange, indicating a very limited aquifer buffering capacity. A lack of buffering capacity is

also supported by the conclusions of Trautz et al. (2013), and by detailed sediment

characterization performed by Varadharajan et al. (2013). This model results provides

IW-1 MW-3

10 cells

Cell length: 0.46 m

Dispersivity: 0.1 m

Time step: 86400 s

v = 0.46 m/d

Porosity: 0.35

4.6 m

IW-1 MW-3IW-1 MW-3

10 cells

Cell length: 0.46 m

Dispersivity: 0.1 m

Time step: 86400 s

v = 0.46 m/d

Porosity: 0.35

4.6 m

75

confidence that the aquifer characterization data (Chapter 2) and the test design provided a sound

basis for interpreting and modeling the chemical data collected during the test period.

Figure 3.20. Measured and modeled groundwater pH in down-gradient well MW-3.

Groundwater pH was modeled using a PHREEQC 1-D transport model without buffering

reactions.

4.4. Comparison to Similar Studies

A growing number of studies have been conducted attempting to simulate a leak of CO2 into

an aquifer (EPRI, 2008; Trautz et al., 2013; Yang et al., 2013; Humez et al., 2014). EPRI

(2008) was the first known field attempt to assess impacts of CO2 intrusion to shallow

groundwater, but was ultimately difficult to model with coupled flow and transport due to the

occurrence of gas exsolution from the aquifer into the vadose zone, and subsequent redissolution

of CO2 into the water table further downgradient. This study attempted to inject CO2 into an

unconfined system, which promoted exsolution of CO2 into the vadose zone. While the study

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

6/6/11 7/26/11 9/14/11 11/3/11 12/23/11 2/11/12 4/1/12 5/21/12 7/10/12 8/29/12

pH

Date

Measured MW-3 No reactions Downhole pH data

76

concluded that various major, minor and trace elements could be released to groundwater due to

CO2 intrusion, the uncertainty regarding possible CO2 exsolution from the test aquifer introduced

questions regarding the strength of these conclusions of strength of the conclusions. Yang et al.

(2013) conducted a push-pull test on a very similar hydrogeologic setting to the current test in

Cranfield, Mississippi. The test consisted of extracting water from the target aquifer, saturating

the water with CO2 and reinjecting the water into the extraction well. After a period of residence

time, the water from the well was sampled for changes in chemistry that would have been

attributable to the presence of CO2 (a tracer was added to correct for wellbore effects and

impacts of physical heterogeneity). Similarly, Humez et al. (2014) conducted a push-pull test in

an aquifer in southern France, using techniques and with comparable results as to that of Yang et

al. (2013).

While push-pull tests are generally economic and informative at a screening level, the test

results are subject to numerous corrections and calculations, based primarily on tracer recovery.

Similarly, the test results are specific to the chosen test well and the near-borehole area, which

can often be disturbed by well drilling and installation. The current study is unique for at least

three reasons. First, a confined aquifer was purposely chosen to limit possible gas exsolution

pathways. Second, a thorough aquifer characterization was conducted in order to understand

and predict the physical and chemical responses to an injection of dissolved CO2. This

characterization included a lengthy baseline monitoring period so that pre-injection conditions

could be well-established. Third, the test was designed such that extracted water was passively

carbonated and allowed to pass through the entire aquifer thickness prior to monitoring at

downgradient wells. Above-ground and downhole measurements of pH, temperature and

pressure were collected throughout the experiment in order to maintain and troubleshoot the

77

injection loop. Excursions in flow rate or pH could be corrected quickly by modifications to the

flow control valves or outlet CO2 pressure, respectively. Downhole pH measurements were

compared to above-ground measurements to evaluate the success of a back-pressured well

purging technique. Ultimately, the extensive site characterization and attention to monitoring

techniques in this study facilitate subsequent data interpretations and modeling.

5. Conclusions

This study evaluated the design and implementation of a controlled CO2 release field

experiment that was performed in a well-confined, well-characterized aquifer. A field test was

performed instead of a laboratory evaluation so that the impacts of CO2 to a groundwater aquifer

could be evaluated in situ. The critical aspects of the design and implementation were the ability

to control experimental conditions in the field (e.g., pressure, temperature, redox) and detect

responses to the disturbance (e.g., hydraulic control, downhole pH, conductivity) with enough

confidence to support conclusions and modeled predictions related to CO2-induced groundwater

quality impacts (e.g., trace element mobilization). The selection of a confined aquifer as

opposed to an unconfined system allowed for minimal, if any, degassing of CO2 from the test

aquifer during the experiment. A closed loop pumping and injection system, and in-line passive

carbonation technology were used to achieve the objective of simulating CO2 leakage into the

aquifer at near aquifer temperature and pressure conditions. Process monitoring results indicated

that the test was performed with minimal variation in key process parameters, including

temperature, pressure and injectate pH. In situ instrumentation deployed in monitoring wells

allowed continuous readings of groundwater pH and conductivity, which were critical

parameters for evaluating the aquifer response to carbonation and acidification. Successful

78

modeling simulation of the pH response using results from the aquifer testing program suggested

that the test was implemented and monitored appropriately. Ultimately, the results presented in

this study provide confidence that future data interpretations and modeling of the field

experiment were not compromised by test design. Future studies seeking to assess impacts of

CO2 on shallow groundwater aquifers can utilize methods employed here to ensure meaningful

test results.

79

REFERENCES







US EPA, 1996. Low stress (low flow) purging and sampling procedure for the collection of

groundwater samples from monitoring wells. EQASOP-GW 001. Revised 2010.

Parkhurst, D.L. and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC

version 3--A computer program for speciation, batch-reaction, one-dimensional transport,

and inverse geochemical calculations: U.S. Geological Survey Techniques and Methods,

book 6, chap. A43, 497 p.

Varadharajan, C. R. M. Tinnacher, J. D. Pugh, R. C. Trautz, L. Zheng N. F. Spycher, J. T.

Birkholzer, H. Castillo-Michel, M. Bianchi, R. A. Esposito, and P. S. Nico. A laboratory

study of the initial effects of dissolved carbon dioxide (CO2) on metal release from

shallow sediments. International Journal of Greenhouse Gas Control. Vol. 19. pp. 183-

211.






Humez, P., Negrel, P., Lagneau, V., Lions, J., Kloppmann, W., Gal, F., Millot, R., Guerrot, C.,

Flehoc, C., Widory, D., Girard, J.-F., 2014. CO2-water-mineral reactions during CO2

leakage: Geochemical and isotopic monitoring of a CO2 injection field test. Chemical

Geology, Vol. 368, pp. 11-30.

http://dx.doi.org/10.1016/j.ijggc.2012.12.030

80

Chapter 4

GEOCHEMICAL IMPACT OF A CONTROLLED CO2 RELEASE FIELD TEST ON A

SHALLOW POTABLE COASTAL PLAIN AQUIFER

Abstract

Geologic sequestration of carbon dioxide has the potential to mitigate concerns over

emissions of greenhouse gas to the atmosphere. The technology involves injected carbon

dioxide into deep geologic reservoirs that are sufficiently protected from drinking water sources,

such as shallow freshwater aquifers. However, the potential for gas migration from deep

reservoirs into potable water sources exists due to geologic features such as faults and fractures

and man-made conduits such as well boreholes. Therefore, it is necessary to assess the impact

that a leak of carbon dioxide would have to a potable aquifer. In this study, carbon dioxide was

introduced into a shallow aquifer in the United States Gulf Coast, a region well-suited for

geologic sequestration, in a controlled release field test. The test was designed to mimic the

migration of a carbon dioxide gas bubble and dissolution into a shallow aquifer, and to monitor

the geochemical impacts to the aquifer resulting from the release. Results at the test site showed

that no constituent was mobilized in excess of US EPA maximum contaminant levels, but that

many constituents (major and minor cations) were released in a pulse-like response at levels

above their baseline concentrations. Dissolution of trace carbonate and pyrite in the aquifer are

hypothesized to have triggered cation exchange reactions, a dominant geochemical process

affecting major and minor cation behavior in the aquifer. Overall, the test has shown that the

migration of carbon dioxide into a drinking water can mobilize ions into solution, but at levels

that are not likely to be of concern to human health.

81

1. Introduction

Potential gas leakage into potable aquifer systems, although a low probability event, is a

major concern for those planning to utilize geologic sequestration for purposes of mitigating CO2

releases to the atmosphere. According to Harvey et al. (2012), the most concerning release

scenario may be that of slow, diffusive leakage from a wellbore or geologic conduit due to its

difficulty to detect for long periods of time. Under this scenario, the fate of CO2 is primarily

governed by the structure and reactivity of the overlying geologic formations. Assuming

structural pathways exist for gas migration, the fate of CO2 depends upon chemical composition

of the aquifer matrix and porewater and their potential interactions with CO2 under specific

temperature and pressure conditions.

In the aqueous phase, the most important reaction will involve dissolution of CO2,

formation of carbonic acid, and subsequent dissociation of carbonic acid (Harvey et al., 2012).

During the dissociation process, protons are released to solution and pH decreases. These

reactions in isolation may or may not be deleterious to water quality, depending upon the extent

of acidification. In fact, the primary risk to potable water supplies due to CO2 leakage into the

aquifer will result from the reactions between dissolved CO2 and the host aquifer mineral

assemblage (Apps et al., 2008). One such reaction is the dissolution of carbonate minerals such

as calcite (Langmuir, 1997):

(1) CaCO3 + CO2(g) + H2O = Ca2+

+ 2HCO3-

Carbonate mineral dissolution can release elements such as calcium, magnesium, iron

and manganese to solution, in addition to other carbonate-forming minor and trace elements.

Other important reactions may include the pH-dependent surface complexation of trace elements

82

onto iron oxyhydroxides or other sorbing surfaces, as represented by the following surface

complexation reaction between arsenate and iron oxyhydroxide:

(12) ≡FeOH-1/2

+ 2 H+ + AsO4

-3 = ≡FeOAsO3H

-3/2 + H2O

where ≡FeOH-1/2

represents a surface functional group on iron oxyhydroxide, and ≡FeOAsO3H-

3/2 represents a monodentate inner sphere surface species wherein arsenic is bound to the iron

oxyhydroxide surface (EPRI, 2009). In reducing environments, sulfide solubilization may result

in release of iron and sulfur, in addition to other common sulfides by a reaction such as that for

mackinawite:

(13) FeS + H+ = Fe

2+ + HS

-

The specific reactions that take place will depend upon the aquifer initial conditions, including

pH, redox state, mineral assemblage, temperature and pressure.

Proper assessment of risk will require development of models capable of predicting

impacts to drinking water sources, and the testing of models against field observations.

Confidence in modeled results is greatly enhanced if comparable to field observations (Xu et al.,

2004). Kharaka et al. (2009) and EPRI (2008) provide evidence that primary geochemical

effects resulting from CO2 intrusion into an aquifer system are carbonate and oxide mineral

dissolution as well as ion exchange. Kharaka et al. (2009) reported geochemical changes in a

1500 m deep sandstone aquifer following injection of CO2 into the Frio Sandstone in Texas. A

drop in pH to approximately 3 s.u. was interpreted to have mobilized significant calcium, iron

and manganese from carbonates and metal oxides. Likewise, EPRI (2008) injected CO2 into a

shallow, unconfined aquifer system and observed a decrease in pH – from pH 7 to 6 – and

increased bicarbonate, calcium and magnesium. The study was ultimately difficult to model

83

with coupled flow and transport due to the occurrence of gas exsolution from the aquifer into the

vadose zone, and subsequent redissolution of CO2 into the water table further downgradient.

To strengthen the current understanding of water quality impacts resulting from potential

CO2 leakage, the Electric Power Research Institute (EPRI) funded a field experiment to test the

effects of elevated CO2 on water quality in a shallow aquifer. The goal of the experiment was to

simulate a leak of CO2 into a shallow aquifer and observe the effects on water quality as it

dissolved into the aquifer. Described in greater detail in Chapter 3 and in Trautz et al. (2012),

the test was designed based upon thorough aquifer characterization and planning.

Chapter 4 presents the results of the experiment and a discussion of the possible

mechanisms underlying field observations. Results are assessed based on their statistical and

regulatory significance and interpretations are provided as to possible geochemical mechanisms

at work. The results of this effort can be used to inform the assessment of risk from geologic

storage projects and the development of models capable of predicting major changes in water

quality resulting from CO2 leakage.

2. Site Location and Regional Hydrogeologic Setting

Site location and regional hydrogeologic setting are described in Chapter 2.

3. Methods

3.1. Site characterization

Methods pertaining to site drilling, well installations and aquifer testing are described in

detail in Chapter 2.

84

3.2. Groundwater sampling and analysis

Groundwater sampling and analytical methods are described in detail in Chapter 2.

3.3. Well layout and test design

The well layout and test design are described in detail in Chapters 2 and 3, respectively.

4. Results

4.1. Intrawell statistics and comparison to regulatory levels

Summaries of pre- and post-CO2 injection concentration ranges for major, minor and

trace constituents are provided in Table 4.1 and. There were no exceedances of US EPA

maximum contaminant levels (MCLs) for any constituent during the test period. All constituents

were evaluated for baseline monitoring period stationarity using box-and-whisker plots (Figure

4.1) in order to determine whether interwell or intrawell comparisons were appropriate.

Although some parameters did appear to reflect stationarity, as required for an interwell

comparison, enough parameters were found to be non-stationary to suggest that an intrawell

comparison was the most appropriate statistical method for the test site (Table 4.3). Therefore,

intrawell analyses were performed on all parameters for this data set. MANAGES, EPRI's data

management and statistical analysis software, was used to automatically perform the statistical

comparison using the following procedure: Outlier Test > Determine Detection Frequency >

Normality Test > Limit Calculation >Comparison to Compliance Data.

85

Table 4.1 Summary of cation and anion concentrations compared to US EPA MCLs

Parameter Units Baseline Range Baseline

Mean

Post-Injection

Range

US EPA

MCL

Calcium mg/L 1.9-6.2 2.9 1.7-15

Magnesium mg/L 0.83-1.9 1.33 0.73-7.8

Sodium mg/L 140-190 157 130-280

Potassium mg/L 1.8-7.6 2.94 1.8-6.1

Silicon mg/L 8.4-13 11.6 11-56

Barium mg/L 0.04-0.11 0.06 0.04-0.48 2

Strontium mg/L 0.07-0.37 0.10 0.06-0.55

Ferric Iron mg/L 0-0.67 0.23 0.01-31.7

Ferrous Iron mg/L 0.05-0.64 0.33 0.04-7.6

Manganese mg/L 0.03-0.11 0.07 0.04-0.65

Lithium mg/L 0.01-0.23 0.02 0.02-0.06

Aluminum mg/L <0.023-0.047 <0.023 <0.023-0.24

Chloride mg/L 13-32 25 20-29 250

Sulfate mg/L <0.015-2.5 0.34 0.034-27 250

Fluoride mg/L 0.18-0.60 0.45 0.05-0.67 4

86

Table 4.2 Summary of trace element concentrations compared to US EPA MCLs

Parameter Units Baseline Range Baseline

Mean

Post-Injection

Range

US EPA

MCL

Silver mg/L <0.00025 <0.00025 <0.00025-0.0007

Arsenic mg/L <0.0013 <0.0013 <0.0013 0.01

Beryllium mg/L <0.00025 <0.00025 <0.00025-0.0007 0.004

Cadmium mg/L <0.000095 <0.000095 <0.000095-0.00024 0.005

Cobalt mg/L <0.00015 <0.00015 <0.00015-0.012

Chromium mg/L <0.0025-0.007 <0.0025 <0.0025-0.013 0.1

Copper mg/L <0.0011 <0.0011 <0.0011-0.002 1.3

Mercury mg/L <0.00007 <0.00007 <0.00007-0.00023 0.002

Molybdenum mg/L 0.002-0.013 0.005 <0.0015-0.012

Nickel mg/L <0.002-0.037 0.002 <0.002-0.1

Lead mg/L <0.0002-0.0009 <0.0002 <0.0002-0.0009 0.015

Antimony mg/L <0.0023-0.003 <0.0023 <0.0023-0.003 0.006

Selenium mg/L <0.001-0.001 <0.001 <0.001-0.0021 0.05

Thallium mg/L <0.0005 <0.0005 <0.0005 0.002

Zinc mg/L <0.0083-0.028 <0.0083 <0.0083-0.036 5

87

Figure 4.1 Box-and-whisker plots illustrating stationary and non-stationary baseline datasets

Table 4.3 Summary of stationary and non-stationary chemical parameters during the baseline

sampling period

Analyte Category Stationary Non-Stationary

Major/Minor Cations Ca, Sr, Na, Si Mg, Fe, Mn, Ba, K, Li

Anions HCO3, Cl SO4

Trace Elements* Mo

Field Parameters Temperature Conductivity, pH

Redox Indicators/Other Ammonia, Methane, Ethane, Fe(2),

Fe(3), CO2, ORP

*Most trace element data were non-detect during the baseline study period, preventing creation

of meaningful box-and-whisker plots. Data were assumed non-stationary.

Although no regulatory levels were exceeded, a large percentage of the post-injection

data exceeded background levels and a majority of these metals exhibited an increasing trend in

concentrations above background, indicative of CO2-induced mobilization. Parameters

exhibiting statistical exceedances in the most wells were typically major or minor cations (Table

88

4.4). With the exception of Cr and Ni, less frequent exceedances were observed for trace

elements (Table 4.4).

Table 4.4 Summary of statistical exceedances above background in each well for each cation

MW-1 MW-2 MW-3 MW-4

Element # Events Element # Events Element # Events Element # Events

Ba 22 Ba 35 Fe 23 Fe 4

Si 22 Ca 35 Mn 23 Ba 3

Fe 21 Fe 35 Si 22 Pb 3

Li 21 K 35 Ba 20 Ca 2

Sr 21 Li 35 Mg 20 Co 2

Ca 20 Mg 35 Be 14 K 2

Mg 20 Mn 35 Ca 13 Li 2

Mn 20 Si 35 Ni 12 Mg 2

Na 20 Sr 35 Cr 9 Mn 2

K 19 Cr 31 Na 8 Na 2

Cr 11 Ni 19 Co 6 Si 2

Hg 2 Na 15 Sr 5 Sr 2

Al 1 Co 8 Zn 2 Cu 1

Co 1 Zn 1 Ag 1 Ag 0

Cu 1 Ag 0 Cd 1 Al 0

Ni 1 Al 0 Hg 1 As 0

Pb 1 As 0 Sb 1 Be 0

Ag 0 Be 0 Al 0 Cd 0

As 0 Cd 0 As 0 Cr 0

Be 0 Cu 0 Cu 0 Hg 0

Cd 0 Hg 0 K 0 Mo 0

Mo 0 Mo 0 Li 0 Ni 0

Sb 0 Pb 0 Mo 0 Sb 0

Se 0 Sb 0 Pb 0 Se 0

Tl 0 Se

Tl

0 Se 0 Tl 0

Zn 0 0 Tl 0 Zn 0

Exceeded in All Wells: Fe>Si>Ba=Mn>Mg>Ca>Sr>Li>K>Na>Co

Exceeded in 3 Wells: Cr>Ni

Exceeded in 2 Wells: Pb>Hg=Zn>Cu

Exceeded in 1 Well: Be>>Cd=Sb=Ag=Al

Exceeded in 0 Wells: Cd=As=Mo=Se=Tl

89

4.2. Temporal trends

Temporal trends for inorganic constituents are discussed below, and illustrated in the

context of four major test periods (Table 4.5): A, B, C, and D. Test period A represents a period

of static baseline testing, where ambient groundwater was sampled under natural flow

conditions. Test period B is a period of induced gradient by pumping from PW-1 and injecting

non-carbonated water into IW-1. Test period C represents no change in pumping or injection

rates, but the dissolution of CO2 into the injectate stream. Test period D represents a return to

non-pumping conditions.

Table 4.5 Summary of test period durations and sampling schedule

Test Period Start Date End Date Approx.

Duration (mos)

Wells

Sampled

Pre-CO2 injection baseline 2-Sep-2010 18-Oct-

2011 13

All wells

Pre-pumping (static baseline) 2-Sep-2010 12-Aug-

2011 11

All wells

Pumping (dynamic baseline) 12-Aug-

2011

18-Oct-

2011 2

MW, BG

wells

CO2 injection (pumping

continues)

18-Oct-

2011

23-Mar-

2012 5

MW, BG

wells

Post-CO2 injection 23-Mar-

2012 15-Jan-2013 10

MW, BG

wells

4.2.1. Dissolved CO2 plume indicators (pH, conductivity, alkalinity, Eh)

Arrival of the dissolved CO2 plume was indicated by sharp decreases in pH at all wells,

reaching a minimum pH reflecting that of the injectate (Figure 4.2). The arrival of dissolved

CO2 at MW-3 was indicated 7 days after start of CO2 injection by sharp decreases in pH and

increases in Eh, conductivity and alkalinity. Considering data from all downgradient wells, pH

decreased to as low as 4.66 from a baseline range of 7.36-8, and increased slightly after pumping

90

and injection ended (Figure 4.2). Eh increased sharply up to sustained positive values during the

injection phase, and decreased slightly after the active pumping and injection phase ended

(Figure 4.3). Conductivity exhibited a pulse-like post-injection response reaching a short-term

peak of nearly double the baseline values (Figure 4.4). Field alkalinity concentrations also

exhibited a pulse-like response, reaching peaks at approximately double the baseline

concentration range in downgradient wells (Figure 4.5).

Figure 4.2 pH trends during baseline, injection and post-injection time periods.

91

Figure 4.3 Eh trends during baseline, injection and post-injection time periods.

Figure 4.4 Conductivity trends during baseline, injection and post-injection time periods.

92

Figure 4.5 Alkalinity trends during baseline, injection and post-injection time periods.

4.2.2. Major and minor cations (Ca, Mg, Ba, Sr, Mn, Si, Fe, Si, K, Li, Na)

The temporal trends of Ca, Mg, Ba, Sr, Mn, total Fe, Na and Si were all very similar to one

another, and to the trends of both alkalinity and electrical conductivity. In most cases,

concentrations gradually declined to near baseline values and increased again to new stable

levels after pumping and injection ceased. In most cases, the stable post-injection concentrations

were less than the peak concentrations observed during active injection, with the exception of Ca

which rebounded temporarily to the maximum injection phase concentration. Calcium responses

in all wells are shown in Figure 4.6 as an example of typical responses for Ca, Mg, Ba, Sr, and

Mn.

93

Figure 4.6 Calcium trends during baseline, injection and post-injection time periods.

Dissolved ferrous and ferric iron displayed different responses from one another during the

active injection phase (Figure 4.7). Baseline and post-injection concentrations for each were

similar, but the increase in ferric iron was much more pronounced and pulse-like than for ferrous

iron. In this respect, ferric iron behaved more similarly to other divalent cations.

Dissolved silicon responded similarly to ferric iron and other divalent cations, characterized

by a sharp increase after injection and subsequent decline toward baseline concentrations as

injection continued (Figure 4.8). Concentrations rebounded gradually to a nearly stable

concentration after the injection phase ended.

94

Figure 4.7 Trends of ferrous and ferric iron, showing markedly different responses during the

CO2 injection but similar post-injection behavior.

Figure 4.8 Silicon trends during baseline, injection and post-injection time.

10

100

-400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Silic

on

(m

g/L

)

Days after Start of CO2 Injection

MW-1 MW-2 MW-3 MW-4 BG-1 Begin Pumping Start CO2 End CO2

Baseline Post-CO2

C DBA

Inject CO2

95

Monovalent cations potassium and lithium were similar in that sharp concentrations increases

occurred after injection, although at a lower peak concentration than the maximum baseline

concentration and a more gradual decline in concentration after the initial increase (Figure 4.9).

Sodium concentrations increased in a pulse-like response relative to baseline concentrations and

returned to baseline concentrations, even after the active pumping and injection phase (Figure

4.10).

Figure 4.9 Trends of potassium and lithium, showing responses to CO2 injection against highly

variable baseline concentrations.

4.2.3. Trace elements (Ag, Al, As, Be, Co, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, Tl, Zn)

Arsenic and Tl exhibited no detectable response to the active injection phase, and were not

detected throughout the experiment. Selenium was only detected during baseline and post-

injection periods, exhibiting no evidence of CO2-induced release. Silver and Cd were only

detected once during the active CO2 injection phase at MW-3, 15 days after injection began.

Cadmium was also detected on one event in the post-injection monitoring phase.

96

Figure 4.10 Sodium trends during baseline, injection and post-injection time.

Aluminum, Cu, Pb, Hg, Zn, and Sb all exhibited detections throughout the experiment, with

no clear increasing trends related to CO2 injection (Figure 4.114). Molybdenum was unique

among detectable trace elements, exhibiting decreasing concentrations during the active injection

and post-injection phase of the project (Figure 4.12).

100

1000

-400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Sod

ium

(m

g/L

)



Baseline Post-CO2

C DBA

Inject CO2

97

Figure 4.11 Trends of Al, Cu, Pb, Hg, Zn and Sb, showing sporadic nature of

detection throughout all test periods.

98

Figure 4.12 Molybdenum concentrations over time, showing decreases in concentration

following CO2 injection

Beryllium, Co, Cr and Ni all exhibited noticeable increasing trends during the injection

and/or post-injection monitoring periods (Figure 4.13). Beryllium exhibited an increasing trend

only in MW-3 beginning 29 days after the injection began and persisting into the post-injection

phase. Cobalt increased during the test period, with the highest increases occurring in the most

downgradient well MW-4. Nickel increases were most notable in wells MW-1 and MW-2. Both

Co and Ni exhibited elevated concentrations immediately prior to the baseline pumping phase

immediately after installation of ERT probes used for cross-well resistivity monitoring,

suggesting that stainless steel components could be an alternate source of at least Co and Ni, if

not other metals (Sb, Zn and Mo also increased on this sample event). The elevations observed

during the CO2 injection phase did not necessarily coincide with anticipated plume arrival times

0.001

0.01

0.1

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Mo

lyb

den

um

(m

g/L

)


MW-1

MW-2

MW-3

MW-4

BG-1

CO2Baseline Post-CO2

C DBA

Inject CO2

99

as indicated by changes in pH and conductivity. Chromium increased notably in wells MW-3

and MW-2, with a lesser response in MW-1, and no increase in MW-4. Chromium behavior

resembled that of other major and minor cations.

4.2.4. Inorganic anions (Cl, SO4, F, NO3, NO2) and dissolved organic carbon

Chloride concentrations remained stable throughout the test, with the exception of a sharp

decrease immediately prior to CO2 injection (Figure 4.14). Dissolved sulfate concentrations

remained low until seven months after the test ended, when concentrations rose as high as 27

mg/L (Figure 4.15). Fluoride concentrations decreased during the test, sharply at MW-3, and did

not recover to baseline concentrations after the test (Figure 4.16). Dissolved organic carbon

Figure 4.13 Trends of Ni, Co, Cr and Be, showing increasing trends during the CO2

injection phase. Relationship of Co and Ni trends to CO2 injection are suspect due to

timing of response in multiple wells.

100

appeared relatively stable during the test, although concentrations did appear to increase

immediately after the active phase (Figure 4.17).

Figure 4.14 Trends of chloride concentrations, showing mostly stable concentrations during the

test period.

5. Discussion

5.1. Response to CO2 behavioral categories

Based on the observed temporal trends and statistical evaluation, the responses of various

constituents to CO2 can be grouped into four major behavioral categories (Table 4.6): Types I, II,

III and IV. Type I constituents were either not detected throughout the duration of the

experiment, or they did not show significant or sustained deviations from background conditions.

1

10

100

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Ch

lori

de

(m

g/L

)



Baseline Post-CO2

C DBA

Inject CO2

101

Figure 4.15 Trends of sulfate concentrations, showing an increase during the active injection

period.

Figure 4.16 Trends of fluoride concentrations, showing decreases during the injection period.

0.01

0.1

1

10

100

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Sulf

ate

(m

g/L

)



Baseline Post-CO2

C DBA

Inject CO2

0.01

0.1

1

10

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Flu

ori

de

(m

g/L

)


MW-1

MW-2

MW-3

MW-4

BG-1

Baseline Post-CO2

C DBA

Inject CO2

102

Figure 4.17 Trends of dissolved organic carbon, showing increases during the injection period.

Type II constituents did exhibit some apparent response to CO2, but are known to or are highly

likely to have been sourced from stainless steel components of ERT probes installed for purposes

of resistivity monitoring during the test. Type III constituents are those which consistently

exceeded baseline concentrations during the test at all wells, and displayed very similar temporal

trends throughout the test. Type IV constituents exhibited an overall decreasing trend in

response to CO2.

5.1.1. Type I: No significant detectable response

A significant result of the study is that both As and Pb are Type I constituents, in contrast

to modeled predictions of Wang and Jaffe (2004) and Zheng et al (2009) or results from a field

experiment at the ZERT site (Kharaka et al. 2010).

0.1

1

10

100

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500

Dis

solv

ed

Org

anic

Car

bo

n (

mg

/L)



Baseline Post-CO2

C DBA

Inject CO2

103

Table 4.6 Behavioral categories

Trend Description Trend

Category

Constituents Comments

Concentrations are at or

below method detection

and/or reporting levels

(with or without a minor

random detection) or do

not deviate significantly

from background

I Cations: Al, Sb,

As, Be, Cd, Cu,

Pb, Hg, P, Se,

Ag, Tl

Anions/other:

Br, Cl, NO3-,

NO2-, SO4

2-,

H2S

Beryllium was non-

detect for all wells

except MW-3,

which showed a

delayed Type III

trend

Concentrations become

elevated after ERT probes

are installed and active

II Co, Ni, Zn Type III trend for

Co observed in

MW-4 only after

CO2 arrives

Pulse response and/or

increasing concentrations

observed in response to

CO2 breakthrough

III Ca, Mg, Ba, Sr,

Fe, Mn, Na, Si,

alkalinity, K,

Li, Cr electrical

cond.

K and Li elevated in

baseline period for

MW-3 and BG-1

Concentrations decrease in

response to CO2

breakthrough

IV NH3, Methane,

Acetic acid,

Mo, F

Likewise, Karmalidis et al (2013) suggested that Cr, Pb, Mn and Fe could exceed EPA maximum

contaminant levels in sandstone aquifers reacting with CO2. The aquifer studied in this

experiment is most similar in geologic setting and composition to that studied by Yang et al

(2013) in a Gulf Coastal Plain aquifer in Natchez, Mississippi. A push-pull test into a very

similar aquifer revealed As and Pb concentrations at approximately 3% and 1%, respectively, of

their EPA maximum contaminant levels (Yang et al., 2013). Other constituents exhibiting Type

I behavior included many oxyanions, which are either likely to be non-reactive (Cl, Br) or whose

mobilization may have been suppressed by a low-pH and favorable adsorption environment (Sb,

104

As, Se, P). Redox-sensitive oxyanions NO3, NO2, and SO4 did not respond significantly,

suggesting that introduction of oxygen during the experiment was not a complicating issue.

Beryllium is also classified as a Type I constituent, although its behavior at MW-3

suggests a delayed Type III trend. In the cases of Al, Cd, Cu, Hg, and Ag, the detections

throughout the experiment were sporadic and temporally isolated enough so that a direct link to

mobilization by CO2 could not be established with confidence. In a companion laboratory study,

Varadharajan et al. (2013) examined sediments from the current test site and found that Ag, Be,

Cd, Cr, Cu and Pb all exhibited low release potential under acidified conditions.

5.1.2. Type II: Alternate source

Although Type II constituents exhibited increasing trends in multiple wells throughout

the test, the direct linkage of these constituents to CO2 cannot be established with confidence.

Several constituents (Zn, Sb, Co, Ni, Mo) exhibited a short-term increase in concentration when

ERT probes with stainless steel components were installed in monitoring wells approximately 90

days prior to CO2 injection. LANL (2007) performed an exhaustive review of the reliability of

chemical data from wells with variable construction methods, and found that wells with stainless

steel components as part of the screened intervals could produce false positives for Fe, Cr, Ni,

Mn, Si, Mo, P and S. Iron, Cr and Ni were reported as the most likely to leach from the well

screens, but the specific metals would be a function of the type of steel. For Co and Ni, elevated

concentrations were observed in multiple wells simultaneously prior to the time of CO2 arrival,

and concentrations appeared to decrease when the probes were removed.

105

Figure 4.18 Nickel and cobalt trends, showing possible impact from downhole probes.

Although the downhole equipment was a possible source of metals during the

experiment, there are geologic sources that must be considered. Varadharajan et al. (2013)

examined sediments from the current test site, and found that Co, Ni and Zn were all subject to

mobilization under acidified conditions, and that Ni and Zn were only sourced from an organic-

rich sand that was not found widespread in the aquifer. Cobalt has been found to be mobilized

106

by CO2 in multiple laboratory studies (Lu et al., 2010; Smyth et al., 2009; Little and Jackson,

2010) and exceeded baseline concentrations in all four monitoring wells during the current field

test. Additionally, Co levels remained elevated in MW-4 after the ERT probes were removed,

suggesting a possible geologic source in the aquifer.

The detections of Zn and Sb in MW-3 could also be attributed to the stainless steel, but

they were not significant enough to be a concern. Similarly, a slight increase in Mo was

observed upon ERT probe installation, but the presence of Mo in baseline monitoring and

decreasing concentrations during the experiment suggest that the probes were not a significant

influence on Mo response.

Type III: Significant response to CO2

There is a growing amount of evidence that Type III constituents will be the most likely to be

mobilized in the event of CO2 leakage into a freshwater aquifer. They are ubiquitous in geologic

materials, commonly associated with ion exchange sites, bound within readily soluble carbonate

minerals, or exist as components of soluble oxides or sulfides. The susceptibility of these same

constituents to release from carbonated conditions is reported by laboratory studies (Lu et al.,

2010; Smyth et al., 2009; Little and Jackson, 2010) and a field test at a very similar geologic

setting (Yang et al., 2013). Varadharajan et al. (2013) performed carbonated water leaching tests

on sediments from the current test aquifer and concluded that fast-acting processes such as cation

exchange and carbonate dissolution could be largely responsible for increased concentrations of

many ions. Selective extractions showed that Ca, Mg, Na, K, Si, Al, Ba, Sr and Mn could be

mobilized by all sediment types through fast-acting mechanisms such as cation exchange or

107

carbonate dissolution. A sample of organic-rich sand from the aquifer leached these elements as

much as an order of magnitude higher in concentration than the sandy bulk aquifer sediments.

Assuming cation exchange is an important mechanism, there are multiple possibilities for a

cation exchange trigger, including calcium from dissolution of carbonate minerals, iron from

pyrite dissolution or simply protonation of exchange surfaces. Varadharajan et al. (2013)

reported evidence of calcite in the bulk sandy aquifer sediments identified using micro X-ray

spectroscopy. Based upon saturation indices alone, carbonates may have been a source of Ca,

Mg, Mn and Fe (Figure 4.19).

Figure 4.19 Saturation indices of siderite, calcite, dolomite and rhodochrosite, suggesting the

possibility of carbonate dissolution and release of Ca, Mg, Mn and Fe.

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

8/10/10 2/26/11 9/14/11 4/1/12 10/18/12

Sid

eri

te S

I

Date

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

8/10/10 2/26/11 9/14/11 4/1/12 10/18/12

Cal

cite

SI

Date

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

8/10/10 2/26/11 9/14/11 4/1/12 10/18/12

Rh

od

och

rosi

teSI

Date

-8.0

-7.0

-6.0

-5.0

-4.0

-3.0

-2.0

-1.0

0.0

1.0

8/10/10 2/26/11 9/14/11 4/1/12 10/18/12

Do

lom

ite

SI

Date

108

Another possible cation exchange trigger is Fe released from pyrite dissolution. The rise in

Eh values as the CO2 plume migrated through the aquifer may be attributable to equilibrium with

pyrite (Figure 4.20), which was found in both euhedral and framboidal form in the organic-rich

sediments and detected by x-ray diffraction in the sandy and clay-rich sediments. Field-

measured pH and Eh values during the test period agree well with the theoretical redox couple

for FeS2/SO42-

, suggesting that pyrite dissolution may be an important factor for ion exchange

reactions.

Figure 4.20 Eh-pH diagram illustrating stability fields of ferrous iron, Fe(OH)3am, and pyrite.

5.1.3. Type IV: Decreasing response to CO2

Some constituents decreased in concentration during the CO2 injection test. For NH3,

methane and acetic acid, the decrease could have been in response to changes in redox conditions

or disruption of the dissolved gas phase equilibrium. Molybdenum and F, as oxyanions, may

have been immobilized through adsorption under acidified conditions. The relationship between

109

Mo and pH is indicative of oxyanion sorption behavior (Figure 4.21), and is very similar in both

concentrations and relationship to pH to that reported by Smedley et al. (2014) for streamwaters

in England and Wales.

Figure 4.21 Relationship between molybdenum and pH during the experiment.

5.1.4. Impacts of site heterogeneity on data interpretations

The groundwater chemical data interpretations presented here must also be considered in the

context of companion studies, including cross-well resistivity monitoring (Wu et al., 2012) and

laboratory sediment characterization studies (Varadharajan et al., 2013). Cross-well resistivity

monitoring coupled with downhole gamma ray logs provided clear evidence that vertical

physical heterogeneity in the aquifer created discrete flow paths for the injected dissolved CO2

and resulting high-conductivity plumes (Figure 4.22). Resistivity inversions of near-borehole

data for MW-3 revealed that the initial decreases in resistivity occurred near the top of the well

110

(interval 1) at approximately 10 days, followed by appearance of two discrete low resistivity

plumes arriving simultaneously at 21 days in the middle-upper and lower portions of the aquifer

(intervals 2 and 3). These portions of the aquifer are characterized by relatively low gamma-ray

emissions, typical of coarser-grained sand intervals with relatively higher permeability than silt-

and clay-bearing zones. At 23 days, a low-resistivity signature was observed in the middle

portion of the aquifer (interval 4), peaking at nearly 31 days and passing through MW-3

sometime after 44 days.

Figure 4.22 Cross-well resistivity monitoring results (Wu et al., 2012), illustrating progression of

high-conductivity plume past MW-3 over time.

Laboratory sediment characterizations of these discrete flow paths are available, and provide

a unique opportunity to identify depth-discrete impacts in an otherwise depth-integrated

111

monitoring system. All intervals are composed primarily of quartz sand, with varying amounts

of clay minerals, feldspars and sulfides. The bulk sand (intervals 2 and 3) contains very small

amounts of calcite and exhibited the lowest measured cation exchange capacity. The organic-

rich interval (4) contained more abundant pyrite (with some framboidal pyrite identified through

SEM), higher clay (illite) content, and exhibited nearly 4 times higher cation exchange capacity

than the bulk sediment.

Interpretations of the data through coupled geochemical reaction and transport modeling

must consider not only the presence of physical and geochemical heterogeneity, but also the

averaging effect of a typical monitoring well in a heterogeneous aquifer. It is reasonable to

conclude based on the resistivity monitoring and companion laboratory study results that the

dissolved CO2 plume progressed through the aquifer impacting different geochemical

environments at variable flow rates. While this heterogeneity was obvious using geophysical

methods and detailed laboratory experiments, it must be considered that the monitoring well

measurement is an averaged concentration of all contributions from the target aquifer,

dampening the potential impact of the thinner and less permeable organic-rich layer.

6. Conclusions

The test showed that the primary constituents of concern due to CO2 intrusion into a

sandy aquifer system are major and minor cations. These cations were likely released due to

cation exchange triggered by dissolution of trace carbonate or pyrite in the aquifer. No

constituent exceeded a level of regulatory concern in this test, although some trace elements did

show statistically significant exceedances above baseline concentrations. These elements were

most likely sourced from a thin organic-rich layer and associated with pyrite dissolution or

112

exchange sites on organic matter or clay minerals. Cobalt and Ni were likely elevated during the

experiment, at least in part, due to leaching of stainless steel components of downhole

geophysical monitoring equipment. Certain oxyanions appeared to be immobilized by the CO2

plume, providing useful insight regarding a potential remedial technique for oxyanions in

groundwater.

The study showed that downhole pH and conductivity measurements provided adequate,

low-cost methods for detecting the arrival of a dissolved CO2 plume in an aquifer. Constituents

such as alkalinity or major cations do not provide useful indicator parameters due to their “pulse-

like” response to the advancing CO2 plume. More complex methods such as cross-well

resistivity provided the most informative information regarding the nature of plume movement in

the aquifer, but is less likely to be practical in a detection monitoring application. Companion

laboratory experiments provided insight as to the important geochemical mechanisms to

consider, and informed the interpretation of temporal trends observed in site monitoring wells.

Overall, this study represents a well-designed and implemented controlled CO2 release

field test that provides valuable information to the regulatory community and public regarding

the risk of CO2 leakage into drinking water aquifers. At the current site, the impact of CO2

leakage to the aquifer was primarily limited to mobilization of major and minor cations. The site

is considered representative of a sandy, coastal plain aquifer, located in a region of the United

States that contains vast deep geologic sequestration opportunities. Continued research into the

risks associated with geologic sequestration of CO2 should facilitate decision-making and

permitting efforts related to full-scale CO2 mitigation efforts.

113

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Electric Power Research Institute (EPRI), 2009. CD-MUSIC reaction database for modeling

adsorption of oxyanions on iron oxyhydroxides. EPRI, Palo Alto, CA, and Southern

Company Services, Inc.: 2009. Technical Report 1017921.

Harvey, O.R., N.P. Qafoku, K.J. Cantrell, G. Lee, J.E. Amonette, and Brown, C.F., 2013.

Geochemical Implications of Gas Leakage associated with Geologic CO2 Storage: A

Qualitative Review. Environmental Science and Technology, Vol. 47, pp. 23−36.

Karmalidis, A.K., Torres, S.G., Hakala, J.A., Shao, H., Cantrell, K.J., Caroll, S., 2013. Trace

metal source terms in carbon sequestration environments. Environmental Science and

Technology, Vol. 47, No. 1, pp. 322-329.

Kharaka, Y.K., Thordsen, J.J., Kakouros, E., Ambats, G., Herkelrath, W.N., Beers, S.R.,

Birkholzer, J.T., Apps, J.A., Spycher, N.F., Zheng, L., Trautz, R.C., Rauch, H.W.,

Gullickson, K.S., 2010. Changes in the chemistry of shallow groundwater related to the

2008 injection of CO2 at the ZERT field site, Bozeman, Montana. Environmental Earth

Sciences, Vol. 60, pp. 273–284.

Kharaka, Y.K., Thordsden, J.J., Hovorka, S.D., Nance, H.S. , Cole, R., Phelps, T.J. and Knauss,

K.G., 2009. Potential environmental issues of CO2 storage in deep saline aquifers:

Geochemical results from the Frio-I brine pilot test, Texas, USA. Applied Geochemistry,

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Los Alamos National Laboratory (LANL), 2007. Well screen analysis report, Rev. 2. Los

Alamos National Laboratory document. LA-UR-07-2852. Los Alamos, New Mexico.

Little, M. G. and Jackson, R. B., 2010. Potential impacts of leakage from deepCO2

geosequestration on overlying freshwater aquifers. Environmental Science and

Technology. 2010, Vol. 44, No. 23, pp. 9225−9232.

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resources as a result of leakage from CO2 geological storage: A batch-reaction

experiment. Environmental Earth Sciences, Vol. 60, No. 2, pp. 335−348.

Smyth, R. C.; Hovorka, S. D.; Lu, J. M.; Romanak, K. D.; Partin, J. W.; Wong, C.; Yang, C. B.,

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field studies. In Greenhouse Gas Control Technologies 9, Gale, J., Herzog, H., Braitsch,

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19. pp. 183-211.

Wang, S. and P.R. Jaffe, 2004. Dissolution of a mineral phase in potable aquifers due to CO2

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Wu, B.; Shao, H.; Wang, Z.; Hu, Y.; Tang, Y. J.; Jun, Y.-S., 2010. Viability and metal reduction

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http://dx.doi.org/10.1016/j.ijggc.2012.12.030

115

Chapter 5

SUMMARY

Carbon capture and storage (CCS), specifically by means of geologic sequestration (GS),

is a developing technology to reduce CO2 emissions to the atmosphere. This technology

involves separating CO2 from flue gas and transporting the CO2 to underground storage locations

that are isolated from the atmosphere. These storage locations are typically permeable and

porous geologic formations that are not useful for any other purpose, such as drinking water.

The objectives of this study were to:

1. Investigate whether sequestered CO2 released from a geologic storage reservoir will

have an adverse impact on underground sources of drinking water from a dominantly

quartz-rich aquifer, and

2. Identify geochemical mechanisms responsible for releasing elements under

carbonated conditions.

In order to achieve these objectives, a thorough geochemical and physical characterization of a

test aquifer was conducted, dissolved CO2 was injected into the test aquifer, and the groundwater

monitored for metals mobilization.

In Chapter 2, the baseline geochemical and physical characterization of the test site were

documented and compared to other sites in the Southeastern United States. The site was found

to be a well-confined aquifer with physical and chemical characteristics that are similar to other

United States gulf coastal plain aquifers. A geochemical model based upon the concept of

aquifer freshening showed that ion exchange is a dominant factor affecting major ion

116

composition of the aquifer. Sediment analysis revealed that clay and sulfide minerals likely play

an important role in affecting the trace element composition of the aquifer.

Chapter 3 documented the design and implementation of the field test so that test results

could be properly interpreted and modeled. Site selection was a key part of the study. Due to

the potential volatility of injected dissolved carbon dioxide, it was critical that the aquifer was

well-confined and that the fluid delivery system operated in a closed loop. This concept has not

been duplicated in similar field efforts. Process monitoring during the test proved that injection

test was conducted with minimal disturbance to temperature and pressure, key factors affecting

gas solubility. Injectate maintained a consistently low pH of approximately 5, so that response in

downgradient monitoring wells was obvious. Downhole monitoring of pH and conductivity

provided high-resolution data that were used to interpret and substantiate aquifer chemical and

physical characteristics that were the subject of Chapter 2. Additionally, a backpressure

sampling system was developed and proved necessary to obtain surface pH measurements

similar to downhole pH measurements.

Chapter 4 focused on interpreting the dissolved chemical data during the test, comparing

the post-injection data to pre-injection conditions. There were no exceedances of US EPA

maximum contaminant levels during the test, although statistically significant increases above

background values were documented for a variety of constituents. Based on the observed

temporal trends and statistical evaluation, the responses of various constituents to CO2 can be

grouped into four major behavioral categories: Types I, II, III and IV. Type I constituents (Al,

Sb, As, Be, Cd, Cu, Pb, Hg, P, Se, Ag, Tl, Br, Cl, NO3, NO2, SO4, H2S) were either not detected

throughout the duration of the experiment, or they did not show significant or sustained

deviations from background conditions. Type II constituents (Co, Ni, Zn) did exhibit some

117

apparent response to CO2, but are known to or are highly likely to have been sourced from

stainless steel components of ERT probes installed for purposes of resistivity monitoring during

the test. Type III constituents (Ca, Mg, Ba, Sr, Fe, Mn, Na, Si, alkalinity, K, Li, Cr) are those

which consistently exceeded baseline concentrations during the test at all wells, and displayed

very similar temporal trends throughout the test. Type IV constituents (NH3, CH4, acetic acid,

Mo, F) exhibited an overall decreasing trend in response to CO2.

The key results of the study include:

1. The impact of elevated dissolved CO2 on a Gulf coastal plain aquifer system can be

simulated in the field with careful control over the site selection, fluid delivery system

design and monitoring techniques.

2. pH and conductivity are valuable indicator parameters for detecting impacts

groundwater resulting from elevated dissolved CO2. Accurate pH measurements are

critical, and a backpressure sampling system proved valuable in obtaining accurate

surface pH measurements.

3. No constituent exceeded a US EPA maximum contaminant level in response to

elevated CO2, although statistically significant exceedances over background were

shown for many constituents.

4. Intrawell statistical methods are preferred over interwell statistical methods, and pre-

disturbance chemical data is critical to understanding impacts.

5. The major impact of elevated dissolved CO2 at the study site was an increase in major

and minor cations, most likely due to ion exchange reactions. Dissolution of pyrite or

carbonates are likely associated with triggering ion exchange reactions.

118

6. Many constituents either showed no response or decreased in concentration as a result

of elevated CO2. This may be attributable to increased adsorption tendency of

oxyanions such as arsenic and fluoride at lower pH.

If geologic sequestration occurs at full-scale projects in the United States Gulf Coast

region, the results of this study suggest that impacts at sites similar to the Plant Daniel site in

Mississippi are limited in increases in major and minor cations at levels below established

drinking water standards.

For constituents such as molybdenum and fluoride, dissolved CO2 may act to remove the

element from the dissolved phase. This observation provides a possible research path forward

for site remediation development where the constituents of concern may include oxyanions.

Additional research could be conducted to further understand the effect of site heterogeneity on

dissolved groundwater chemistry. Chapter 4 and other studies are finding substantial evidence

that data interpretations can be complicated by the presence of vertical and horizontal chemical

and physical heterogeneity in aquifers. Baseline chemical data from relatively closely spaced

monitoring wells show significant non-stationarity, precluding the use of interwell statistical

methods even for a relatively homogeneous site. Given the degree of non-stationarity observed

at this relatively homogeneous coastal plain aquifer, the adequacy of interwell statistical methods

at any site should be questioned.

119

APPENDICES

120

Table A-1. Field parameter data

Well Date Temp DO Eh pH Conductivity Ferrous

Fe

Field

H2S

Field Alkalinity

Celcius mg/L mV S.U. umhos/cm mg/L mg/L mg/L as CaCO3

BG-1 9/2/2010 23.60 0.08 -253 8.25 669

BG-1 10/6/2010 21.90 0.10 -61 7.86 682 0.07 319

BG-1 10/29/2010 21.70 0.14 -95 8.41 637 0.29 0.00 275

BG-1 12/3/2010 22.70 0.58 -204 8.59 706 0.31 0.00 321

BG-1 12/27/2010 21.60 0.41 -181 7.85 685 0.09 0.00 300

BG-1 1/25/2011 22.80 0.01 -225 7.84 690 0.28 0.00 310

BG-1 2/23/2011 21.80 0.15 -27 7.67 648 0.43 0.00 290

BG-1 5/18/2011 22.20 0.07 -260 8.24 670 0.07 0.24 264

BG-1 6/22/2011 23.90 0.04 -184 8.08 657 0.27 0.00 300

BG-1 7/18/2011 23.30 0.02 -175 8.57 677 0.12 0.00 280

BG-1 9/7/2011 22.20 0.28 -30 8.39 668 0.07 0.16 326

BG-1 9/14/2011 22.40 0.25 -27 8.34 676 0.01 0.16 319

BG-1 9/21/2011 22.00 0.26 -119 8.21 668 0.14 0.16 322

BG-1 9/28/2011 21.70 0.25 -123 8.19 671 0.21 0.16 326

BG-1 10/19/2011 21.80 0.12 -238 7.78 673 0.02 0.16 326

BG-1 11/10/2011 21.80 0.20 -230 8.36 683 0.05 0.16 336

BG-1 12/1/2011 21.50 0.18 -231 8.30 637 0.02 0.11 325

BG-1 3/15/2012 21.90 0.16 -218 8.23 662 0.02 0.00 339

BG-1 4/11/2012 22.40 0.21 -175 8.11 663 0.04 0.00 276

BG-1 10/4/2012 23.70 -216 8.24 681 0.16 297

BG-1 1/14/2013 21.20 0.09 -230 8.11 661 0.16 0.00 277

IW-1 9/2/2010 23.50 0.08 -319 8.18 656

IW-1 12/3/2010 23.10 0.14 -121 8.52 713 0.30 0.00 302

IW-1 12/28/2010 22.30 0.04 -231 7.81 692 0.47 0.00 310

IW-1 1/26/2011 22.30 0.02 -188 7.84 682 0.38 0.00 290

IW-1 2/22/2011 21.80 1.53 -10 7.99 656 0.01 0.00 308

IW-1 10/5/2012 23.40 19 5.44 607 0.24 245

MW-1 2/12/2010 22.30 0.24 -210 7.08 657

121


Fe

Field

H2S

Field Alkalinity


MW-1 6/28/2010 23.00 0.47 -82 7.46 644

MW-1 8/25/2010 24.00 0.22 -101 7.75 621 0.44

MW-1 10/5/2010 22.10 0.24 -171 7.36 645 0.42 0.00 305

MW-1 10/28/2010 21.90 0.24 -26 7.56 623 0.55 0.00 287

MW-1 12/3/2010 22.10 0.11 -163 8.32 670 0.38 0.00 308

MW-1 12/29/2010 22.50 0.16 -180 7.64 685 0.64 0.00 312

MW-1 1/26/2011 22.70 0.02 -156 7.58 664 0.36 0.00 310

MW-1 2/23/2011 21.90 0.34 -16 7.56 639 0.58 0.00 290

MW-1 5/19/2011 22.20 0.14 -217 7.78 639 0.55 0.00 265

MW-1 6/21/2011 25.20 0.27 -137 7.77 645 0.32 0.00 300

MW-1 7/19/2011 23.30 0.12 -17 7.71 643 0.21 0.00 290

MW-1 9/8/2011 22.00 0.39 -13 7.62 631 0.49 0.00 309

MW-1 9/16/2011 22.00 0.40 -103 7.80 640 0.58 0.00 312

MW-1 9/22/2011 22.20 0.21 -114 7.71 641 0.27 0.00 316

MW-1 9/28/2011 22.20 0.30 -119 7.85 646 0.62 0.00 315

MW-1 10/19/2011 21.90 0.30 -194 7.70 641 0.31 0.00 319

MW-1 11/10/2011 21.90 0.23 -190 7.75 659 0.54 0.00 320

MW-1 12/1/2011 22.00 0.18 -187 7.75 611 0.56 0.00 314

MW-1 1/6/2012 21.90 0.37 -194 7.78 631 0.06 0.00 310

MW-1 1/9/2012 22.00 0.70 -180 7.75 579 0.04 0.00

MW-1 1/11/2012 21.30 0.56 -182 7.91 593 0.05 0.00 320

MW-1 1/13/2012 21.50 0.24 -189 8.25 577 0.16 0.00 300

MW-1 1/16/2012 22.00 0.53 -180 7.73 623 0.47 0.00 313

MW-1 1/18/2012 21.80 0.62 -179 7.76 623 0.48 0.00 311

MW-1 1/20/2012 21.90 0.44 -174 7.69 627 0.35 0.00 309

MW-1 1/23/2012 21.90 0.45 -184 7.72 640 0.40 0.00 313

MW-1 1/30/2012 21.80 0.37 -185 7.71 648 0.52 0.00 310

MW-1 2/1/2012 21.70 0.10 -184 7.70 644 0.48 0.00 310

MW-1 2/3/2012 21.70 0.22 -175 7.61 631 0.56 0.00 300

MW-1 2/6/2012 21.60 0.15 -168 7.54 656 0.48 0.00 295

122


Fe

Field

H2S

Field Alkalinity


MW-1 2/8/2012 21.80 0.17 -166 7.43 684 0.66 0.00 295

MW-1 2/10/2012 21.60 0.13 -146 7.34 723 0.48 0.00 290

MW-1 2/13/2012 21.80 0.15 -127 7.28 814 1.66 0.00 256

MW-1 2/15/2012 21.80 0.30 -110 7.04 879 2.34 0.00 437

MW-1 2/17/2012 21.80 0.18 -96 6.79 942 2.80 0.00 488

MW-1 2/29/2012 21.90 0.35 -43 6.05 1226 3.22 0.00 641

MW-1 3/2/2012 21.90 0.27 -125 6.01 1208 5.80 0.00 649

MW-1 3/5/2012 22.00 0.28 -38 5.94 1229 4.40 0.11 643

MW-1 3/7/2012 21.90 0.20 -89 5.83 1187 5.20 0.05 647

MW-1 3/9/2012 21.80 0.27 -27 5.75 1199 5.40 0.05 648

MW-1 3/12/2012 21.80 0.20 13 5.67 1166 6.00 0.11 643

MW-1 3/14/2012 22.10 0.13 -36 5.50 1133 6.00 0.05 616

MW-1 3/19/2012 22.00 0.23 -86 5.63 1110 6.00 0.11 589

MW-1 3/21/2012 21.90 0.40 -42 5.61 1165 6.00 0.11 575

MW-1 3/23/2012 22.00 0.26 -6 5.53 1083 6.40 0.00 585

MW-1 3/26/2012 21.80 0.81 8 5.66 1142 2.12 0.00 574

MW-1 4/2/2012 22.00 0.54 31 5.10 1114 6.60 0.00 561

MW-1 4/9/2012 22.00 0.30 15 5.68 881 1.90 0.00

MW-1 4/12/2012 21.60 0.20 31 5.57 1091 5.00 0.00 450

MW-1 4/16/2012 22.00 0.57 41 5.65 1154 3.04 536

MW-1 10/5/2012 22.00 -19 6.01 1045 2.76 448

MW-1 1/15/2013 21.70 0.14 -11 6.04 982 2.70 444

MW-2 2/12/2010 22.10 0.13 -270 7.14 659

MW-2 6/28/2010 23.40 0.23 -31 7.50 628

MW-2 8/25/2010 23.20 0.15 -49 7.93 614 0.14

MW-2 10/5/2010 21.80 0.14 -173 7.61 641 0.21 307

MW-2 10/28/2010 21.80 0.18 -95 7.83 623 0.46 285

MW-2 12/2/2010 22.60 0.14 -183 8.31 673 0.23 0.00 302

MW-2 12/28/2010 22.40 0.33 -186 7.61 684 0.00 290

MW-2 1/26/2011 22.30 0.02 -214 7.72 674 0.26 0.00 275

123


Fe

Field

H2S

Field Alkalinity


MW-2 2/22/2011 21.70 0.15 -23 7.57 637 0.55 0.00 292

MW-2 5/20/2011 22.40 0.12 -234 7.93 644 0.45 0.00 243

MW-2 6/21/2011 24.50 0.33 -151 7.95 649 0.31 0.00 284

MW-2 7/19/2011 25.00 0.13 -116 7.81 650 0.18 0.00 270

MW-2 9/7/2011 22.00 0.39 -49 7.90 635 0.42 0.00 314

MW-2 9/15/2011 22.00 0.29 -69 7.70 643 0.42 0.00 308

MW-2 9/21/2011 22.00 0.25 -139 7.82 642 0.58 0.00 305

MW-2 9/28/2011 21.80 0.24 -118 7.88 646 0.60 0.00 318

MW-2 10/19/2011 21.70 0.14 -209 7.39 643 0.38 0.00 314

MW-2 11/10/2011 21.80 0.23 -207 7.96 658 0.09 0.00 322

MW-2 11/16/2011 21.90 0.25 -200 7.73 652 0.05 0.00 308

MW-2 12/1/2011 21.80 0.21 -193 7.83 607 0.42 0.00 320

MW-2 12/7/2011 21.70 0.16 -188 7.85 639 0.34 0.00 319

MW-2 12/14/2011 21.80 0.21 -188 7.77 656 0.35 0.00 316

MW-2 1/6/2012 21.90 0.25 -49 6.35 897 5.00 0.00 378

MW-2 1/9/2012 21.90 0.46 -36 6.26 942 6.40 0.00

MW-2 1/11/2012 21.30 0.48 -56 6.41 942 5.50 0.00 350

MW-2 1/13/2012 21.40 0.40 -45 6.39 975 6.00 0.00 360

MW-2 1/16/2012 21.90 0.36 1 5.78 1079 4.40 0.00 557

MW-2 1/18/2012 21.70 0.31 10 5.81 1046 4.60 0.00 541

MW-2 1/20/2012 21.90 0.30 11 5.64 1014 6.00 0.00 551

MW-2 1/23/2012 21.80 0.25 17 5.70 1030 5.40 0.00 535

MW-2 1/27/2012 21.70 0.17 2 5.65 989 5.20 0.00 260

MW-2 1/30/2012 21.70 0.39 -3 5.69 958 5.60 0.00 310

MW-2 2/1/2012 21.80 0.22 -10 5.71 952 6.00 0.00 330

MW-2 2/3/2012 21.70 0.26 4 5.58 913 6.60 0.00 348

MW-2 2/6/2012 21.50 0.26 -4 5.62 898 6.40 0.00 335

MW-2 2/8/2012 21.70 0.20 -11 5.59 878 6.40 0.00 320

MW-2 2/10/2012 21.60 0.19 8 5.62 870 6.40 0.00 340

MW-2 2/13/2012 21.80 0.17 25 5.64 877 6.00 0.00 432

124


Fe

Field

H2S

Field Alkalinity


MW-2 2/15/2012 21.70 0.39 32 5.42 872 7.40 0.00 423

MW-2 2/17/2012 21.80 0.23 41 5.29 860 2.90 0.00 425

MW-2 2/29/2012 21.70 0.39 -4 5.41 796 2.69 0.00 387

MW-2 3/2/2012 21.80 0.23 -71 5.09 788 7.20 0.00 440

MW-2 3/5/2012 21.90 0.51 16 5.35 769 6.20 0.00 377

MW-2 3/7/2012 21.70 0.18 -45 5.23 761 5.60 0.00 379

MW-2 3/9/2012 21.70 0.26 -9 5.40 763 6.40 0.00 380

MW-2 3/12/2012 21.70 0.15 32 5.33 749 6.40 0.00 375

MW-2 3/14/2012 21.80 0.24 -13 5.40 746 6.80 0.00 366

MW-2 3/19/2012 21.70 0.25 -45 4.74 751 6.60 0.00 366

MW-2 3/21/2012 21.80 0.33 -10 5.05 753 6.60 0.00 355

MW-2 3/23/2012 21.70 0.30 3 5.30 750 7.00 0.00 373

MW-2 3/26/2012 21.80 0.42 34 4.67 787 2.10 0.00 377

MW-2 4/2/2012 21.90 0.24 37 5.10 793 7.60 0.00 404

MW-2 4/9/2012 21.90 0.35 14 5.44 636 5.80 0.00

MW-2 4/11/2012 21.90 0.27 39 5.29 798 6.10 0.00 265

MW-2 4/16/2012 21.80 0.21 34 5.28 850 6.00 0.00 384

MW-2 10/4/2012 23.90 -19 5.56 856 4.24 350

MW-2 1/14/2013 21.50 0.21 42 5.61 864 4.51 315

MW-3 9/2/2010 26.80 0.08 -285 8.24 663

MW-3 10/5/2010 22.10 0.16 -138 7.47 641 0.11 0.00 313

MW-3 10/28/2010 22.10 0.45 -122 8.03 633 0.15 0.00 305

MW-3 12/2/2010 21.70 0.15 -188 8.41 679 0.22 0.00 291

MW-3 12/28/2010 22.70 0.04 -227 7.81 690 0.51 0.00 304

MW-3 1/24/2011 22.10 0.03 -191 7.88 675 0.13 0.00 285

MW-3 2/22/2011 21.80 0.52 -27 7.77 649 0.34 0.00 292

MW-3 5/19/2011 22.30 0.06 -276 8.48 653 0.05 0.00 258

MW-3 6/21/2011 23.50 0.02 -91 7.97 676 0.20 0.00 290

MW-3 7/19/2011 24.70 0.64 -75 8.69 664 0.26 0.00 300

MW-3 7/20/2011 24.20 0.09 -175 8.40 657

125


Fe

Field

H2S

Field Alkalinity


MW-3 7/21/2011 23.70 0.06 -202 8.37 646

MW-3 8/21/2011 22.10 0.14 -260 8.14 666 0.22 0.00 275

MW-3 9/1/2011 22.00 0.24 -236 8.14 635 0.42 0.00 317

MW-3 9/8/2011 22.10 0.13 -200 8.31 637 0.21 0.00 309

MW-3 9/15/2011 22.00 0.20 -219 8.15 640 0.30 0.00 311

MW-3 9/22/2011 22.10 0.16 -227 8.30 643 0.24 0.00 324

MW-3 9/28/2011 22.20 0.32 -243 8.34 651 0.27 0.00 303

MW-3 10/5/2011 22.30 0.17 -160 8.19 638 0.00

MW-3 10/12/2011 22.10 0.18 -261 8.21 641 0.21 0.00 306

MW-3 10/17/2011 22.30 0.20 -254 8.22 641 0.18 0.00 299

MW-3 10/19/2011 22.10 0.19 -253 8.15 640 0.25 0.00 300

MW-3 10/21/2011 22.10 0.12 -242 8.29 639 0.23 0.00 311

MW-3 10/24/2011 22.30 0.14 -239 8.24 624 0.29 0.00 313

MW-3 10/26/2011 22.20 0.10 -234 8.00 626 0.26 0.00 301

MW-3 10/28/2011 22.20 0.15 -176 7.41 658 2.15 0.00 327

MW-3 10/31/2011 22.20 0.20 -80 6.43 779 1.98 0.00 359

MW-3 11/2/2011 22.10 0.21 -67 6.18 888 2.33 0.00 434

MW-3 11/4/2011 21.90 0.38 -52 5.98 1043 1.40 0.00 527

MW-3 11/9/2011 22.20 0.35 -45 5.75 1105 2.89 0.00 556

MW-3 11/10/2011 22.00 0.32 -11 5.54 1082 3.38 0.00 562

MW-3 11/11/2011 21.90 0.41 -10 5.70 1075 3.30 0.00 564

MW-3 11/14/2011 21.80 0.29 -19 5.64 975 3.30 0.00 510

MW-3 11/16/2011 21.90 0.26 5 5.53 950 3.30 0.00 487

MW-3 11/18/2011 21.80 0.23 9 5.62 901 3.14 0.00 467

MW-3 11/21/2011 22.00 0.33 9 5.38 781 3.14 0.12 412

MW-3 11/23/2011 21.90 0.30 16 5.32 762 5.50 0.00 382

MW-3 11/25/2011 21.80 0.29 8 5.52 722 6.50 0.00 370

MW-3 11/28/2011 21.60 0.28 28 5.58 664 6.00 0.11 345

MW-3 11/30/2011 21.70 0.36 36 5.48 679 4.50 0.11 333

MW-3 12/2/2011 21.80 0.22 29 5.53 674 5.00 0.05 323

126


Fe

Field

H2S

Field Alkalinity


MW-3 12/5/2011 21.80 0.33 38 5.38 691 5.00 0.05 323

MW-3 12/7/2011 21.50 0.29 23 5.40 685 4.50 0.11 311

MW-3 12/14/2011 21.80 0.27 42 5.40 700 6.00 0.00 316

MW-3 1/4/2012 21.60 0.35 65 5.64 650 6.00 0.00 303

MW-3 3/15/2012 22.00 0.11 50 4.66 628 2.29 0.00 266

MW-3 4/12/2012 21.70 0.30 32 5.29 622 4.00 0.00 220

MW-3 10/5/2012 22.30 30 5.51 695 2.54 276

MW-3 1/15/2013 21.20 0.16 74 5.51 627 2.45 270

MW-4 9/2/2010 24.00 0.01 -189 8.18 670 0.24

MW-4 10/5/2010 22.20 0.16 -156 7.64 648 0.09 0.00 309

MW-4 10/28/2010 21.80 0.16 -77 7.79 623 0.30 0.00 310

MW-4 12/3/2010 21.90 0.48 -184 8.47 681 0.14 0.00 300

MW-4 12/29/2010 22.10 0.21 -175 7.75 685 0.58 0.00 297

MW-4 1/25/2011 22.60 0.02 -202 7.76 674 0.23 0.00 290

MW-4 2/23/2011 22.10 0.15 -8 7.63 642 0.30 0.00 296

MW-4 5/20/2011 22.50 0.15 -214 7.86 649 0.32 0.00 239

MW-4 6/21/2011 25.50 0.19 -154 7.84 648 0.27 0.00 290

MW-4 7/19/2011 24.40 0.09 -144 7.90 617 0.24 0.00 310

MW-4 9/7/2011 22.00 0.31 10 7.80 631 0.38 0.00 307

MW-4 9/16/2011 22.20 0.26 -127 7.90 639 0.37 0.00 309

MW-4 9/22/2011 22.10 0.31 -88 7.76 642 0.32 0.00 311

MW-4 9/28/2011 22.20 0.27 -105 7.90 645 0.32 0.00 327

MW-4 10/19/2011 22.00 0.22 -198 7.80 639 0.34

MW-4 11/10/2011 21.70 0.19 -195 7.84 656 0.07 0.00 313

MW-4 12/1/2011 21.90 0.34 -183 7.84 607 0.28 0.00 314

MW-4 3/14/2012 22.00 0.11 -143 6.85 630 0.27 0.00 299

MW-4 3/19/2012 22.00 0.19 -162 7.55 643 0.22 0.00 314

MW-4 3/21/2012 22.00 0.36 -174 7.58 638 0.32 0.11 318

MW-4 3/23/2012 21.80 0.38 -148 7.53 638 0.26 0.05 321

MW-4 3/26/2012 22.00 0.34 -144 7.59 675 0.14 0.00 332

127


Fe

Field

H2S

Field Alkalinity


MW-4 4/2/2012 22.00 0.24 -115 7.02 667 0.35 0.00 328

MW-4 4/9/2012 21.90 0.21 -107 7.44 558 0.54 0.00

MW-4 4/11/2012 22.00 0.18 -78 7.22 710 0.48 0.00 290

MW-4 4/16/2012 21.90 0.26 -52 7.09 772 0.86 0.00 367

MW-4 10/4/2012 24.20 -42 6.16 1164 2.18 0.00 425

MW-4 1/15/2013 21.50 0.16 -7 6.06 1112 2.10 0.00 415

PW-1 2/12/2010 22.50 0.06 -318 7.56 663

PW-1 6/28/2010 23.30 0.33 -45 8.38 666

PW-1 8/25/2010 24.20 0.18 -102 8.56 656 0.02

PW-1 12/4/2010 21.70 0.08 -180 8.39 673 0.38 0.00 299

PW-1 12/27/2010 22.60 0.10 -216 7.74 679 0.15 0.00 295

PW-1 1/25/2011 23.30 0.02 -222 7.72 673 0.36 305

PW-1 2/24/2011 22.20 0.35 3 7.70 639 0.31 308

128

Table A-2. Major and minor cation concentrations.

Well Date Al Ba Ca Fe Li Mg Mn K Si Na Sr

mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L

BG-1 9/2/2010 0.1 0.04 2.5 0.24 0.024 0.94 0.04 2.7 12 150 0.084

BG-1 10/6/2010 0.032 0.027 2.5 0.18 0.021 0.81 0.025 2.4 11 160 0.091

BG-1 10/29/2010 0.03 0.044 2.8 0.58 0.02 0.98 0.061 2.4 11 160 0.1

BG-1 12/3/2010 0.028 0.044 2.5 0.58 0.021 1 0.055 2.8 11 150 0.095

BG-1 12/27/2010 0.03 0.046 2.6 0.6 0.02 0.93 0.054 2.3 12 160 0.086

BG-1 1/25/2011 <0.023 0.049 3.2 0.57 0.022 1.1 0.06 2.8 11 160 0.094

BG-1 2/23/2011 <0.023 0.056 2.9 0.59 0.022 1.2 0.078 2.6 13 140 0.089

BG-1 5/18/2011 0.027 0.045 2.9 0.3 0.029 1.2 0.04 5.1 12 190 0.087

BG-1 6/22/2011 <0.023 0.049 2.9 0.22 0.03 0.95 0.043 5.7 11 180 0.098

BG-1 7/18/2011 0.034 0.048 2.7 0.22 0.04 1.2 0.041 6.8 12 170 0.1

BG-1 9/7/2011 0.024 0.043 2.3 0.14 0.033 0.92 0.036 5.4 12 150 0.093

BG-1 9/14/2011 <0.023 0.048 2.4 0.19 0.033 1 0.046 5 12 160 0.099

BG-1 9/21/2011 <0.023 0.045 2.5 0.23 0.027 1 0.054 3.9 12 160 0.093

BG-1 9/28/2011 <0.023 0.051 3 0.027 1.2 0.067 4.5 12 180 0.1

BG-1 10/19/2011 <0.023 0.042 2.9 0.16 0.033 0.9 0.04 4.7 12 150 0.087

BG-1 11/10/2011 <0.023 0.045 2.2 0.24 0.029 0.86 0.048 3.9 12 140 0.084

BG-1 12/1/2011 <0.023 0.046 2.6 0.3 0.03 0.97 0.053 4.4 12 160 0.089

BG-1 3/15/2012 <0.023 0.043 2.3 0.21 0.034 0.91 0.048 4.8 12 150 0.088

BG-1 4/11/2012 0.054 0.059 2.5 0.42 0.025 0.98 0.067 3.6 12 150 0.094

BG-1 10/4/2012 <0.023 0.049 2.4 0.17 0.065 0.87 0.049 6.8 12 150 0.11

BG-1 1/14/2013 <0.023 0.053 2.9 0.32 0.06 1.1 0.059 7 12 180 0.1

IW-1 9/2/2010 <0.023 0.07 3.6 0.33 0.031 2.1 0.093 4.8 11 150 0.16

IW-1 12/3/2010 0.13 0.078 3.5 0.85 0.042 1.8 0.08 7.5 11 150 0.18

IW-1 12/28/2010 <0.023 0.059 2.9 0.89 0.021 1.5 0.07 2.8 12 140 0.11

IW-1 1/26/2011 <0.023 0.068 4.2 0.73 0.025 1.9 0.077 3.9 11 160 0.14

IW-1 2/22/2011 <0.023 0.044 3.3 0.27 0.019 1.3 0.055 2.9 11 150 0.11

IW-1 10/5/2012 0.035 0.051 2.2 0.92 0.02 1.1 0.045 2.4 13 140 0.078

MW-1 2/12/2010 <0.023 0.06 2.8 0.43 0.021 1.6 0.072 2.9 11 150 0.096

MW-1 6/28/2010 <0.023 0.064 3.3 0.66 0.018 1.7 0.095 2.9 10 160 0.098

MW-1 7/30/2010 <0.023 0.061 2.8 0.65 0.02 1.5 0.093 2.8 11 140 0.1

129



MW-1 8/25/2010 <0.023 0.06 3.3 0.69 0.018 1.7 0.096 2.9 10 150 0.099

MW-1 10/5/2010 <0.023 0.063 3 0.72 0.019 1.7 0.1 2.5 11 150 0.11

MW-1 10/28/2010 <0.023 0.056 2.7 0.61 0.021 1.5 0.078 2.9 12 160 0.092

MW-1 12/3/2010 <0.023 0.06 2.5 0.62 0.021 1.6 0.073 3.5 12 160 0.094

MW-1 12/29/2010 <0.023 0.058 2.4 0.61 0.02 1.3 0.066 2.5 12 140 0.082

MW-1 1/26/2011 <0.023 0.06 3 0.59 0.02 1.5 0.075 3 12 160 0.095

MW-1 2/23/2011 <0.023 0.064 3 0.69 0.018 1.4 0.088 3.1 12 150 0.099

MW-1 5/19/2011 <0.023 0.064 3.4 0.8 0.018 1.9 0.092 3.3 12 180 0.093

MW-1 6/21/2011 <0.023 0.065 3.3 0.68 0.017 1.7 0.1 3.3 12 170 0.11

MW-1 7/19/2011 <0.023 0.068 3.1 0.4 0.019 1.8 0.091 3.5 12 150 0.11

MW-1 9/8/2011 <0.023 0.063 2.7 0.84 0.02 1.5 0.086 3.1 12 150 0.096

MW-1 9/16/2011 <0.023 0.059 2.5 0.8 0.021 1.4 0.08 2.8 12 140 0.091

MW-1 9/22/2011 <0.023 0.067 2.8 0.72 0.018 1.6 0.099 2.9 12 160 0.1

MW-1 9/28/2011 <0.023 0.067 3.2 0.31 0.018 1.8 0.096 3.4 12 180 0.11

MW-1 10/19/2011 <0.023 0.062 2.6 0.76 0.018 1.5 0.084 3 12 150 0.092

MW-1 11/10/2011 <0.023 0.059 2.5 0.77 0.019 1.4 0.073 2.6 12 140 0.083

MW-1 12/1/2011 <0.023 0.062 2.7 0.79 0.019 1.5 0.085 3 12 150 0.092

MW-1 1/6/2012 <0.023 0.059 2.8 0.73 0.018 1.5 0.073 2.9 12 150 0.089

MW-1 1/9/2012 0.24 0.057 2.4 0.71 0.018 1.3 0.071 2.9 12 140 0.084

MW-1 1/11/2012 <0.023 0.054 2.3 0.71 0.019 1.3 0.074 2.7 12 140 0.085

MW-1 1/13/2012 <0.023 0.057 2.6 0.72 0.019 1.5 0.072 3 12 150 0.09

MW-1 1/16/2012 <0.023 0.057 2.3 0.71 0.019 1.4 0.075 2.9 12 150 0.09

MW-1 1/18/2012 <0.023 0.055 2.2 0.68 0.019 1.3 0.069 2.8 12 140 0.083

MW-1 1/20/2012 <0.023 0.062 2.2 0.67 0.019 1.5 0.075 3 12 160 0.091

MW-1 1/23/2012 <0.023 0.061 2.5 0.68 0.019 1.7 0.074 3.1 12 160 0.089

MW-1 1/30/2012 <0.023 0.056 2.2 0.69 0.019 1.3 0.069 2.7 12 130 0.083

MW-1 2/1/2012 <0.023 0.059 2.4 0.72 0.019 1.4 0.073 2.9 12 150 0.087

MW-1 2/3/2012 <0.023 0.063 2.5 0.75 0.02 1.5 0.077 3 12 150 0.095

MW-1 2/6/2012 <0.023 0.07 2.9 0.85 0.021 1.7 0.098 3.1 12 170 0.1

MW-1 2/8/2012 <0.023 0.073 2.9 1 0.022 1.8 0.091 3 13 160 0.11

MW-1 2/10/2012 <0.023 0.087 3.4 1.3 0.023 2 0.11 3.6 13 160 0.12

130



MW-1 2/13/2012 <0.023 0.25 7.8 1.9 0.025 3.7 0.32 4 14 200 0.28

MW-1 2/15/2012 <0.023 0.14 5 2.6 0.03 2.9 0.17 3.8 15 190 0.2

MW-1 2/17/2012 <0.023 0.15 5.8 3.2 0.033 3.5 0.17 4.5 17 220 0.22

MW-1 2/29/2012 <0.023 0.29 10 7.3 0.047 5.8 0.35 5.6 28 270 0.39

MW-1 3/2/2012 <0.023 0.28 9.7 6.5 0.047 5.6 0.33 5.5 29 270 0.38

MW-1 3/5/2012 <0.023 0.3 11 7.5 0.051 6 0.37 5.9 34 270 0.42

MW-1 3/7/2012 <0.023 0.27 9.1 6.2 0.052 5.2 0.32 5.2 37 240 0.37

MW-1 3/9/2012 <0.023 0.29 10 6.7 0.053 6.1 0.34 6 40 270 0.41

MW-1 3/12/2012 <0.023 0.31 10 7.2 0.057 5.8 0.35 5.8 45 260 0.41

MW-1 3/14/2012 <0.023 0.3 9.9 7 0.055 5.6 0.34 5.6 48 250 0.39

MW-1 3/19/2012 <0.023 0.29 9.7 7.2 0.058 5.6 0.35 5.4 53 250 0.38

MW-1 3/21/2012 <0.023 0.3 10 7.4 0.058 6 0.37 5.6 55 260 0.39

MW-1 3/23/2012 <0.023 0.28 9.5 7.2 0.059 5.5 0.34 5.4 54 240 0.36

MW-1 3/26/2012 <0.023 0.29 9.7 7.3 0.06 5.6 0.35 5.5 55 240 0.38

MW-1 4/2/2012 <0.023 0.3 9.9 7.6 0.063 5.8 0.36 5.8 56 250 0.41

MW-1 4/9/2012 <0.023 0.3 9.7 7.1 0.061 5.6 0.36 5.7 56 240 0.4

MW-1 4/12/2012 <0.023 0.29 9.6 6.3 0.058 5.6 0.36 5.8 50 250 0.39

MW-1 4/16/2012 <0.023 0.3 10 6.6 0.059 6 0.37 5.7 49 260 0.39

MW-1 10/5/2012 <0.023 0.41 12 12 0.049 7.8 0.49 6.1 35 220 0.52

MW-1 1/15/2013 <0.023 0.33 11 11 0.05 6.6 0.42 6.1 33 220 0.4

MW-2 2/12/2010 0.11 0.059 2.7 0.8 0.02 1.4 0.07 2.4 11 150 0.093

MW-2 6/28/2010 <0.023 0.066 2.9 0.63 0.014 1.3 0.065 2.4 9.6 150 0.095

MW-2 7/30/2010 0.024 0.065 2.8 0.54 0.014 1.4 0.066 2.4 10 140 0.1

MW-2 8/25/2010 0.038 0.06 2.9 0.43 0.013 1.3 0.063 2.3 10 150 0.09

MW-2 10/5/2010 0.023 0.069 3.2 0.51 0.015 1.5 0.075 2.3 11 180 0.11

MW-2 10/28/2010 <0.023 0.049 2.1 0.62 0.018 0.9 0.064 2.3 11 150 0.079

MW-2 12/2/2010 <0.023 0.044 1.9 0.58 0.019 0.94 0.05 2.6 12 150 0.073

MW-2 12/28/2010 <0.023 0.054 2.3 0.66 0.018 1.1 0.061 2.2 12 150 0.079

MW-2 1/26/2011 <0.023 0.066 3.2 0.79 0.019 1.4 0.077 2.9 12 170 0.097

MW-2 2/22/2011 <0.023 0.05 2.2 0.7 0.018 0.83 0.057 2.3 12 150 0.075

MW-2 5/20/2011 <0.023 0.06 2.8 0.73 0.015 1.4 0.069 2.6 11 160 0.087

131



MW-2 6/21/2011 <0.023 0.076 3.4 0.46 0.013 1.4 0.083 3 10 180 0.12

MW-2 7/19/2011 <0.023 0.062 2.9 0.33 0.016 1.5 0.072 2.6 11 170 0.097

MW-2 9/7/2011 <0.023 0.056 2.3 0.69 0.018 0.96 0.062 2.2 12 150 0.081

MW-2 9/15/2011 <0.023 0.054 2.1 0.76 0.018 0.96 0.062 2.1 12 140 0.078

MW-2 9/21/2011 <0.023 0.059 2.5 0.73 0.018 1.1 0.076 2.2 12 160 0.087

MW-2 9/28/2011 <0.023 0.054 2.6 0.53 0.018 1.1 0.068 2.4 12 170 0.083

MW-2 10/19/2011 <0.023 0.053 2.3 0.7 0.019 0.98 0.061 2.1 11 150 0.075

MW-2 11/10/2011 <0.023 0.05 2.2 0.72 0.018 0.92 0.053 2.2 11 140 0.067

MW-2 11/16/2011 <0.023 0.052 2.3 0.7 0.018 0.98 0.058 2.2 11 160 0.072

MW-2 12/1/2011 <0.023 0.05 2.3 0.71 0.019 0.96 0.058 2.2 12 150 0.071

MW-2 12/7/2011 <0.023 0.053 2.2 0.66 0.017 0.96 0.059 2.2 11 150 0.076

MW-2 12/14/2011 <0.023 0.048 2.3 0.71 0.019 1 0.056 2.3 12 160 0.072

MW-2 1/6/2012 <0.023 0.18 6.2 5.2 0.029 3 0.19 3.4 18 210 0.24

MW-2 1/9/2012 0.22 8.4 8.6 0.034 3.8 0.27 3.8 22 230 0.29

MW-2 1/11/2012 0.27 9.6 13 0.037 4.3 0.38 4.1 23 230 0.38

MW-2 1/13/2012 <0.023 0.31 10 14 0.039 5.3 0.38 4.8 25 250 0.4

MW-2 1/16/2012 <0.023 0.29 8.9 16 0.041 4.5 0.34 4.1 33 230 0.36

MW-2 1/18/2012 <0.023 0.34 10 16 0.043 5.3 0.4 5.2 39 280 0.43

MW-2 1/20/2012 0.031 0.3 9.3 16 0.045 4.9 0.35 4.7 40 240 0.37

MW-2 1/23/2012 <0.023 0.31 9.6 17 0.047 4.7 0.36 4.8 42 230 0.36

MW-2 1/27/2012 <0.023 0.29 9.2 16 0.046 4.5 0.35 4.7 41 220 0.34

MW-2 1/30/2012 <0.023 0.29 8.6 17 0.045 4.2 0.36 4.4 42 210 0.34

MW-2 2/1/2012 <0.023 0.26 7.6 16 0.045 3.6 0.32 4 42 190 0.3

MW-2 2/3/2012 <0.023 0.27 7.7 16 0.048 3.7 0.32 4.2 45 200 0.3

MW-2 2/6/2012 0.027 0.26 8.2 15 0.046 3.9 0.35 4.1 41 210 0.3

MW-2 2/8/2012 <0.023 0.24 7.4 14 0.049 3.5 0.31 3.9 43 200 0.28

MW-2 2/10/2012 <0.023 0.24 7 14 0.049 3.4 0.31 3.9 43 180 0.28

MW-2 2/13/2012 <0.023 0.12 4.9 13 0.045 2.7 0.14 3.6 40 200 0.17

MW-2 2/15/2012 <0.023 0.23 6.6 13 0.052 3.1 0.28 3.7 42 190 0.26

MW-2 2/17/2012 0.031 0.29 9.1 13 0.053 4.5 0.27 5.2 41 230 0.33

MW-2 2/29/2012 0.029 0.2 5.8 10 0.048 2.8 0.26 3.6 35 170 0.22

132



MW-2 3/2/2012 <0.023 0.18 5.3 9 0.05 2.6 0.23 3.6 34 170 0.2

MW-2 3/5/2012 0.023 0.17 5.2 8.9 0.048 2.4 0.24 3.3 33 150 0.2

MW-2 3/7/2012 0.023 0.16 5 8.5 0.053 2.3 0.22 3.6 34 170 0.19

MW-2 3/9/2012 0.023 0.18 5.4 8.9 0.05 2.7 0.23 3.9 32 170 0.2

MW-2 3/12/2012 <0.023 0.19 5.6 8.5 0.051 2.7 0.24 3.7 32 170 0.21

MW-2 3/14/2012 <0.023 0.18 5.3 8.7 0.052 2.5 0.23 3.6 32 160 0.2

MW-2 3/19/2012 0.028 0.17 5.3 7.6 0.053 2.5 0.23 3.5 32 170 0.19

MW-2 3/21/2012 0.024 0.19 5.9 8.2 0.054 2.8 0.25 3.9 32 180 0.2

MW-2 3/23/2012 <0.023 0.2 5.9 8.5 0.054 2.9 0.27 3.9 33 170 0.22

MW-2 3/26/2012 <0.023 0.21 6.1 9.1 0.054 3 0.28 3.9 33 170 0.23

MW-2 4/2/2012 <0.023 0.23 7.1 11 0.059 3.6 0.31 4.4 37 170 0.26

MW-2 4/9/2012 <0.023 0.29 8.6 14 0.055 4.3 0.38 5 37 180 0.33

MW-2 4/11/2012 0.025 0.23 7.1 12 0.053 3.4 0.32 4.4 34 170 0.27

MW-2 4/16/2012 <0.023 0.28 8.3 12 0.056 4.1 0.35 4.7 36 170 0.3

MW-2 10/4/2012 <0.023 0.29 8.2 8.5 0.06 4.9 0.32 5.2 39 180 0.34

MW-2 1/14/2013 <0.023 0.29 8.7 8.5 0.061 5.1 0.33 5.7 39 190 0.32

MW-3 9/2/2010 0.37 0.11 6.2 0.094 0.23 1 0.039 0 12 180 0.37

MW-3 10/5/2010 0.03 0.055 3.2 0.36 0.033 1.1 0.042 3 12 180 0.12

MW-3 10/28/2010 <0.023 0.055 3.1 0.35 0.023 1 0.049 2.8 12 160 0.11

MW-3 12/2/2010 <0.023 0.063 3.1 0.37 0.023 1.2 0.055 3.4 12 170 0.13

MW-3 12/28/2010 <0.023 0.06 2.6 0.78 0.021 1.2 0.067 2.2 13 140 0.092

MW-3 1/24/2011 <0.023 0.062 3.5 0.5 0.026 1.3 0.07 3.9 12 150 0.11

MW-3 2/22/2011 <0.023 0.058 3 0.58 0.023 1 0.065 2.6 12 150 0.1

MW-3 5/19/2011 <0.023 0.068 3.2 0.24 0.029 1.4 0.056 4.2 12 160 0.12

MW-3 6/21/2011 <0.023 0.062 2.5 0.1 0.047 0.96 0.029 7.6 10 160 0.12

MW-3 7/19/2011 0.047 0.061 3.2 0.051 0.042 1.3 0.026 6 11 160 0.12

MW-3 7/20/2011 <0.023 0.071 3.4 0.19 0.031 1.5 0.061 4.2 13 160 0.13

MW-3 7/21/2011 <0.023 0.071 3.5 0.31 0.026 1.4 0.082 3.9 12 160 0.12

MW-3 8/21/2011 <0.023 0.072 3.1 0.51 0.025 1.4 0.08 3.1 12 150 0.11

MW-3 8/23/2011 <0.023 0.077 3.6 0.46 0.026 1.7 0.085 3.6 12 170 0.13

MW-3 8/25/2011 0.084 0.064 2.8 0.48 0.024 1.2 0.089 3 12 140 0.11

133



MW-3 8/27/2011 <0.023 0.076 3.2 0.75 0.024 1.5 0.11 3.4 13 160 0.12

MW-3 8/29/2011 <0.023 0.071 3 0.78 0.023 1.4 0.1 3.2 13 150 0.12

MW-3 9/1/2011 <0.023 0.068 2.7 0.69 0.025 1.3 0.073 3.2 13 140 0.11

MW-3 9/8/2011 <0.023 0.069 2.9 0.6 0.026 1.3 0.065 3.9 12 150 0.12

MW-3 9/15/2011 <0.023 0.066 2.7 0.61 0.025 1.2 0.066 3.5 12 140 0.11

MW-3 9/22/2011 <0.023 0.068 2.8 0.54 0.026 1.3 0.073 3.4 11 150 0.12

MW-3 9/28/2011 <0.023 0.064 2.9 0.75 0.024 1.3 0.068 3.8 12 160 0.11

MW-3 10/5/2011 0.12 0.069 3 0.63 0.023 1.3 0.068 3.4 12 150 0.11

MW-3 10/12/2011 <0.023 0.064 2.7 0.65 0.025 1.2 0.09 3.4 12 140 0.1

MW-3 10/17/2011 <0.023 0.061 2.5 0.69 0.024 1.2 0.067 3.1 12 140 0.097

MW-3 10/19/2011 <0.023 0.062 2.6 0.74 0.024 1.2 0.074 3.1 12 140 0.1

MW-3 10/21/2011 <0.023 0.07 3.3 0.84 0.022 1.6 0.086 3.2 12 180 0.11

MW-3 10/24/2011 <0.023 0.063 2.8 0.86 0.022 1.4 0.078 2.8 12 170 0.098

MW-3 10/26/2011 <0.023 0.068 3 0.88 0.021 1.5 0.085 3 12 180 0.11

MW-3 10/28/2011 <0.023 0.088 3.5 1.9 0.023 1.7 0.12 3.1 12 150 0.13

MW-3 10/31/2011 <0.023 0.19 6.5 8.4 0.027 3.3 0.25 3.4 16 160 0.26

MW-3 11/2/2011 <0.023 0.28 9.8 13 0.031 4.9 0.37 4.3 20 200 0.35

MW-3 11/4/2011 <0.023 0.42 14 26 0.038 6.4 0.54 4.5 29 190 0.5

MW-3 11/10/2011 0.034 0.48 15 33 0.047 6.6 0.61 4.8 40 200 0.55

MW-3 11/11/2011 <0.023 0.45 14 35 0.048 6.9 0.65 4.9 43 220 0.53

MW-3 11/14/2011 <0.023 0.41 12 34 0.048 6 0.58 4.4 43 200 0.44

MW-3 11/16/2011 <0.023 0.35 11 27 0.047 5.3 0.49 4.4 41 210 0.39

MW-3 11/18/2011 <0.023 0.32 9.5 22 0.045 4.8 0.45 4.3 38 210 0.35

MW-3 11/21/2011 <0.023 0.28 8.3 19 0.044 4 0.38 4.2 34 180 0.29

MW-3 11/23/2011 <0.023 0.24 7 17 0.044 3.5 0.33 4.1 33 180 0.23

MW-3 11/25/2011 <0.023 0.25 7.3 16 0.044 3.6 0.35 4.4 31 190 0.24

MW-3 11/28/2011 <0.023 0.21 6 14 0.043 3 0.3 4 30 180 0.2

MW-3 11/30/2011 <0.023 0.19 6.2 12 0.041 2.9 0.28 4.1 28 160 0.18

MW-3 12/2/2011 <0.023 0.18 5.1 12 0.04 2.5 0.25 3.7 28 160 0.16

MW-3 12/5/2011 <0.023 0.17 4.8 11 0.038 2.4 0.26 3.8 25 160 0.17

MW-3 12/7/2011 <0.023 0.18 5.6 11 0.038 2.5 0.28 4.1 24 160 0.18

134



MW-3 12/14/2011 <0.023 0.19 6.2 11 0.038 2.7 0.31 4.1 22 160 0.18

MW-3 1/4/2012 <0.023 0.15 5.6 7.4 0.03 2 0.27 3.7 18 150 0.16

MW-3 3/15/2012 0.041 0.088 3.7 2.9 0.024 1.2 0.14 3.2 14 140 0.12

MW-3 4/12/2012 0.046 0.11 5.7 3.7 0.027 1.5 0.22 3.8 16 150 0.17

MW-3 10/5/2012 <0.023 0.17 9.5 6.9 0.041 1.9 0.34 3.8 18 140 0.26

MW-3 1/15/2013 <0.023 0.16 8.5 7 0.043 1.9 0.34 4 19 150 0.2

MW-4 9/2/2010 0.14 0.05 2.3 0.13 0.019 1.2 0.046 2.2 11 150 0.077

MW-4 10/5/2010 0.032 0.046 2.7 0.3 0.008 1.2 0.042 1.8 8.4 150 0.077

MW-4 10/28/2010 <0.023 0.045 2.4 0.41 0.018 1.1 0.047 2.2 11 160 0.079

MW-4 12/3/2010 <0.023 0.051 2.4 0.43 0.019 1.3 0.05 2.7 12 170 0.086

MW-4 12/29/2010 <0.023 0.053 2.5 0.49 0.018 1.3 0.052 2.1 12 150 0.085

MW-4 1/25/2011 <0.023 0.061 3.4 0.44 0.017 1.5 0.062 2.8 11 170 0.1

MW-4 2/23/2011 <0.023 0.054 3 0.45 0.013 1.2 0.055 2.4 11 150 0.089

MW-4 5/20/2011 0.031 0.053 2.8 0.49 0.012 1.4 0.056 2.3 11 160 0.086

MW-4 6/21/2011 <0.023 0.062 3.4 0.39 0.012 1.5 0.066 2.5 11 180 0.11

MW-4 7/19/2011 0.031 0.056 3 0.32 0.013 1.6 0.056 2.3 12 160 0.097

MW-4 9/7/2011 <0.023 0.049 2.2 0.62 0.018 1 0.05 2.1 13 150 0.081

MW-4 9/16/2011 <0.023 0.048 2 0.53 0.018 0.91 0.05 1.8 12 140 0.079

MW-4 9/22/2011 <0.023 0.057 2.8 0.49 0.017 1.2 0.068 2.3 12 190 0.093

MW-4 9/28/2011 <0.023 0.047 2.4 0.59 0.017 1 0.055 2.1 12 170 0.079

MW-4 10/19/2011 <0.023 0.047 2.3 0.49 0.018 0.98 0.052 2.1 12 170 0.076

MW-4 11/10/2011 <0.023 0.042 1.9 0.49 0.018 0.8 0.042 1.8 12 140 0.063

MW-4 12/1/2011 <0.023 0.041 1.9 0.45 0.018 0.79 0.045 1.9 12 150 0.065

MW-4 3/14/2012 <0.023 0.036 1.7 0.47 0.019 0.73 0.038 1.8 12 140 0.059

MW-4 3/19/2012 <0.023 0.038 1.7 0.48 0.019 0.73 0.039 1.8 12 150 0.06

MW-4 3/21/2012 <0.023 0.04 1.8 0.46 0.018 0.78 0.041 1.9 12 160 0.064

MW-4 3/23/2012 <0.023 0.041 1.8 0.47 0.019 0.77 0.041 1.9 12 160 0.063

MW-4 3/26/2012 <0.023 0.041 1.8 0.47 0.018 0.78 0.042 1.9 12 150 0.065

MW-4 4/2/2012 0.024 0.043 2 0.58 0.021 0.86 0.048 2.1 13 160 0.071

MW-4 4/9/2012 <0.023 0.054 2.4 0.77 0.021 1 0.06 2.2 13 160 0.09

135



MW-4 4/11/2012 <0.023 0.059 2.5 0.83 0.021 1.1 0.065 2.3 13 170 0.094

MW-4 4/16/2012 <0.023 0.068 2.9 1.1 0.022 1.2 0.072 2.2 13 180 0.1

MW-4 10/4/2012 <0.023 0.28 9.8 7.5 0.048 4.1 0.29 3.9 26 260 0.37

MW-4 1/15/2013 <0.023 0.29 11 8.5 0.048 4.4 0.3 4.2 28 270 0.37

PW-1 2/12/2010 <0.023 0.057 3.7 0.43 0.019 1.5 0.067 2.7 9.4 150 0.11

PW-1 6/28/2010 0.027 0.044 3.4 <0.05 0.008 1.1 0.024 2.3 5.7 140 0.088

PW-1 7/30/2010 0.025 0.057 3.8 <0.05 0.01 1.3 0.03 2.5 5.8 140 0.11

PW-1 8/25/2010 0.038 0.057 4.2 <0.05 0.01 1.4 0.033 2.7 6.3 160 0.11

PW-1 12/4/2010 <0.023 0.055 2.6 0.71 0.02 1.3 0.07 3.2 12 160 0.088

PW-1 12/27/2010 <0.023 0.049 2.5 0.82 0.019 1.1 0.066 2.3 13 150 0.075

PW-1 1/25/2011 <0.023 0.063 3.3 0.78 0.019 1.4 0.086 2.9 11 150 0.1

PW-1 2/24/2011 <0.023 0.045 2.6 0.42 0.019 0.91 0.06 2.3 11 150 0.086

136

Table A-3. Measured concentrations of dissolved anions and alkalinity

Well Date HCO3 Alkalinity Total Alkalinity Cl Br F NO3 NO2 + NO3 NO2 SO4

mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L

BG-1 9/2/2010 330 330 29 0.31 0.44 <0.018 <0.0087 <0.018 1.8

BG-1 10/6/2010 330 340 26 <1 0.48 <0.018 0.013 <0.018 <1.6

BG-1 10/29/2010 320 330 27 <1 0.57 <0.018 <0.0087 <0.018 <1.6

BG-1 12/3/2010 310 320 26 0.037 0.43 <0.013 <0.0087 <0.013 0.9

BG-1 12/27/2010 320 330 28 0.036 0.45 0.031 0.033 <0.013 0.22

BG-1 1/25/2011 330 330 27 0.032 0.45 <0.013 <0.0087 <0.013 3.4

BG-1 2/23/2011 310 320 27 0.19 0.46 <0.013 0.011 <0.013 0.79

BG-1 5/18/2011 330 340 24 0.041 0.46 <0.013 <0.0087 <0.013 2.6

BG-1 6/22/2011 330 340 28 0.046 0.52 <0.013 <0.013 <0.013 2.3

BG-1 7/18/2011 330 340 27 0.039 0.42 <0.013 <0.013 <0.013 3.4

BG-1 9/7/2011 340 340 26 0.033 0.32 <0.013 <0.013 <0.013 0.93

BG-1 9/14/2011 330 340 28 <0.0041 0.3 <0.013 <0.013 <0.013 1.1

BG-1 9/21/2011 330 340 27 <0.0041 0.41 <0.013 <0.013 <0.013 0.83

BG-1 9/28/2011 340 350 23 <0.0041 0.51 <0.013 <0.013 <0.018 0.89

BG-1 10/19/2011 320 330 29 0.039 0.66 <0.013 <0.013 <0.013 <1.4

BG-1 11/10/2011 330 330 25 0.04 0.59 <0.013 <0.013 <0.013 <1.4

BG-1 12/1/2011 320 320 24 0.035 0.54 <0.018 <0.012 <0.018 <1.4

BG-1 3/15/2012 330 340 27 <0.0041 0.57 <0.018 <0.012 <0.018 <1.4

BG-1 4/11/2012 330 330 27 <0.067 0.72 <0.018 <0.012 <0.018 <1.4

BG-1 10/4/2012 26 2.3

BG-1 1/14/2013 330 340 28 <0.067 0.61 <0.09 <0.09 <0.018 <1.4

IW-1 9/2/2010 330 330 28 0.31 0.49 <0.018 <0.0087 <0.018 1.1

IW-1 12/3/2010 330 340 27 0.037 0.5 <0.013 <0.0087 <0.013 0.17

IW-1 12/28/2010 320 320 30 0.036 0.49 0.034 0.035 <0.013 0.22

IW-1 1/26/2011 320 330 25 0.036 0.5 <0.013 <0.0087 <0.013 0.084

IW-1 2/22/2011 320 330 26 0.039 0.46 0.014 0.018 <0.013 0.21

IW-1 10/5/2012 27 13

MW-1 2/12/2010 310 310 27 0.04 0.44 <0.018 <0.01 <0.018 <1.6

MW-1 6/28/2010 320 330 26 0.044 0.55 <0.018 <0.01 <1.6

MW-1 7/30/2010 320 320 27 0.045 0.52 <0.018 <0.0087 2

137



MW-1 8/25/2010 330 330 27 0.32 0.42 <0.018 <0.0087 <0.018 <1.6

MW-1 10/5/2010 330 340 26 <1 0.52 0.03 0.031 <0.018 <1.6

MW-1 10/28/2010 320 320 26 <1 0.6 <0.018 <0.0087 <0.018 <1.6

MW-1 12/3/2010 320 320 24 0.038 0.42 <0.013 <0.0087 <0.013 0.23

MW-1 12/29/2010 310 310 25 0.036 0.47 0.033 0.035 <0.013 0.32

MW-1 1/26/2011 320 320 26 0.032 0.47 <0.013 <0.0087 <0.013 0.28

MW-1 2/23/2011 320 320 26 0.04 0.45 0.013 0.018 <0.013 0.3

MW-1 5/19/2011 320 320 23 0.04 0.48 <0.013 <0.0087 <0.013 0.023

MW-1 6/21/2011 330 330 28 0.044 0.51 <0.013 <0.013 <0.013 0.076

MW-1 7/19/2011 310 310 27 0.04 0.51 <0.013 <0.013 <0.013 0.12

MW-1 9/8/2011 320 320 26 0.041 0.41 <0.013 <0.013 <0.013 0.11

MW-1 9/16/2011 320 320 26 <0.0041 0.3 <0.013 <0.013 <0.013 0.14

MW-1 9/22/2011 320 330 26 <0.0041 0.43 <0.013 <0.013 <0.013 <0.015

MW-1 9/28/2011 330 330 <0.0041 0.54 <0.013 <0.013 <0.018 <0.015

MW-1 10/19/2011 310 310 29 0.038 0.67 <0.013 <0.013 <0.013 0.11

MW-1 11/9/2011 0.016 0.6 <1.4

MW-1 11/10/2011 300 300 22 0.037 0.41 <0.013 <0.013 <0.013 0.12

MW-1 12/1/2011 310 310 24 0.034 0.58 <0.018 <0.012 <0.018 <1.4

MW-1 3/14/2012 650 650 27 <0.0041 0.11 <0.018 <0.012 <0.018 <1.4

MW-1 4/12/2012 560 580 26 <0.067 0.14 <0.018 <0.012 <0.018 <1.4

MW-1 10/5/2012 25 6

MW-1 1/15/2013 530 530 27 <0.067 0.11 <0.018 <0.018 <0.018 <1.4

MW-2 2/12/2010 310 310 27 0.038 0.47 <0.018 <0.01 <0.018 <1.6

MW-2 6/28/2010 320 320 25 0.045 0.55 <0.018 <0.01 <1.6

MW-2 7/30/2010 320 320 26 0.044 0.54 <0.018 0.012 <1.6

MW-2 8/25/2010 320 330 21 0.29 0.38 <0.018 <0.0087 0.025 <1.6

MW-2 10/5/2010 320 330 26 <1 0.52 <0.018 0.016 <0.018 <1.6

MW-2 10/28/2010 320 320 26 <1 0.59 <0.018 <0.0087 <0.018 <1.6

MW-2 12/2/2010 300 300 24 0.036 0.46 <0.013 <0.0087 <0.013 0.14

MW-2 12/28/2010 310 310 25 0.034 0.43 0.026 0.027 <0.013 0.3

MW-2 1/26/2011 320 320 25 0.032 0.46 <0.013 <0.0087 <0.013 0.028

138



MW-2 2/22/2011 310 310 28 0.039 0.42 0.014 0.018 <0.013 0.24

MW-2 5/20/2011 320 320 24 0.043 0.47 <0.013 <0.0087 <0.013 0.077

MW-2 6/21/2011 320 330 28 0.043 0.45 <0.013 <0.013 <0.013 0.06

MW-2 7/19/2011 320 320 26 0.039 0.44 <0.013 <0.013 <0.013 0.025

MW-2 9/7/2011 320 320 26 0.04 0.43 <0.013 <0.013 <0.013 0.081

MW-2 9/15/2011 320 320 27 0.04 0.4 <0.013 <0.013 <0.013 0.13

MW-2 9/21/2011 320 330 26 <0.0041 0.45 <0.013 <0.013 <0.013 <0.015

MW-2 9/28/2011 310 320 18 <0.0041 0.53 <0.013 <0.013 <0.018 <0.015

MW-2 10/19/2011 310 310 23 0.037 0.42 <0.013 <0.013 <0.013 0.57

MW-2 11/10/2011 300 300 24 0.037 0.41 <0.013 <0.013 <0.013 0.12

MW-2 11/16/2011 300 300 23 0.04 0.4 <0.013 <0.013 <0.013 0.2

MW-2 12/1/2011 300 310 24 0.024 0.57 <0.018 <0.012 <0.018 <1.4

MW-2 3/14/2012 390 390 26 <0.0041 0.13 <0.018 <0.012 <0.018 1.5

MW-2 4/11/2012 420 420 27 <0.067 0.12 <0.018 <0.012 <0.018 <1.4

MW-2 1/14/2013 470 470 28 <0.067 0.048 <0.018 <0.018 <0.018 <1.4

MW-3 9/2/2010 260 440 13 0.29 0.18 <0.018 <0.0087 <0.018 2.5

MW-3 10/5/2010 320 330 26 <1 0.52 0.018 0.019 <0.018 <1.6

MW-3 10/28/2010 320 330 26 <1 0.58 <0.018 <0.0087 <0.018 <1.6

MW-3 12/2/2010 300 300 28 0.037 0.43 <0.013 <0.0087 <0.013 0.17

MW-3 12/28/2010 310 320 29 0.036 0.45 0.026 0.027 <0.013 0.25

MW-3 1/24/2011 320 330 25 0.035 0.46 <0.013 <0.0087 <0.013 0.22

MW-3 2/22/2011 310 320 26 0.041 0.43 <0.013 <0.0087 <0.013 0.28

MW-3 5/19/2011 320 330 21 0.046 0.47 <0.013 <0.0087 <0.013 0.35

MW-3 6/21/2011 220 250 27 0.051 0.42 <0.013 <0.013 <0.013 0.5

MW-3 7/19/2011 310 330 26 0.033 0.46 <0.013 <0.013 <0.013 0.55

MW-3 7/20/2011 320 320 27 0.041 0.46 <0.013 <0.013 <0.013 0.49

MW-3 7/21/2011 320 330 27 0.042 0.45 <0.013 <0.013 <0.013 0.57

MW-3 8/21/2011 320 320 26 0.042 0.42 <0.013 <0.013 0.013 0.75

MW-3 8/23/2011 320 330 26 0.039 0.4 <0.013 <0.013 <0.013 0.63

MW-3 8/25/2011 310 320 26 0.041 0.42 <0.013 <0.013 <0.013 0.41

MW-3 8/27/2011 320 320 27 0.038 0.4 <0.013 <0.013 <0.013 0.43

139



MW-3 8/29/2011 310 390 26 0.041 0.33 <0.013 <0.013 <0.013 0.36

MW-3 9/1/2011 320 320 26 0.021 0.36 <0.013 <0.013 <0.013 0.32

MW-3 9/8/2011 320 320 25 0.04 0.34 <0.013 <0.013 <0.013 0.35

MW-3 9/15/2011 310 320 27 <0.0041 0.37 <0.013 <0.013 <0.013 0.3

MW-3 9/22/2011 320 330 26 <0.0041 0.33 <0.013 <0.013 <0.013 0.26

MW-3 9/28/2011 330 330 22 <0.0041 0.53 <0.013 <0.013 <0.018 0.28

MW-3 10/5/2011 330 330 15 <0.0041 0.53 <0.013 <0.013 <0.013 0.37

MW-3 10/12/2011 310 310 23 <0.0041 0.52 <0.013 <0.013 <0.013 <0.015

MW-3 10/19/2011 310 320 28 0.035 0.42 <0.013 <0.013 <0.013 0.19

MW-3 10/26/2011 300 310 22 0.004 0.43 <0.013 <0.013 <0.013 0.2

MW-3 11/2/2011 20 0.035 0.34 0.027 0.027 <0.013 0.34

MW-3 11/9/2011 24 0.035 0.18 1.7

MW-3 11/10/2011 590 590 24 0.022 0.054 <0.013 <0.013 <0.013 0.47

MW-3 11/16/2011 470 470 24 <0.0041 0.081 <0.013 <0.013 <0.013 0.46

MW-3 11/23/2011 390 390 24 <0.0041 0.064 <0.018 <0.012 0.018 <1.4

MW-3 11/30/2011 340 340 24 0.024 0.051 <0.018 <0.012 <0.018 <1.4

MW-3 3/15/2012 310 310 26 <0.0041 0.13 <0.018 <0.012 <0.018 <1.4

MW-3 4/12/2012 320 320 26 <0.067 0.14 <0.018 <0.012 <0.018 <1.4

MW-3 10/5/2012 27 27

MW-3 1/15/2013 350 350 28 <0.067 0.085 <0.018 <0.018 <0.018 <1.4

MW-4 9/2/2010 320 320 32 0.31 0.51 <0.018 <0.0087 <0.018 1.1

MW-4 10/5/2010 320 330 26 <1 0.52 0.024 0.025 <0.018 <1.6

MW-4 10/28/2010 320 320 26 <1 0.59 <0.018 <0.0087 <0.018 <1.6

MW-4 12/3/2010 320 320 29 0.039 0.41 <0.013 <0.0087 <0.013 0.16

MW-4 12/29/2010 310 320 27 0.036 0.47 0.029 0.031 <0.013 0.11

MW-4 1/25/2011 320 320 24 0.034 0.46 <0.013 <0.0087 <0.013 0.058

MW-4 2/23/2011 310 320 27 0.041 0.44 0.017 0.021 <0.013 0.16

MW-4 5/20/2011 320 320 22 0.041 0.46 <0.013 <0.0087 <0.013 <0.015

MW-4 6/21/2011 330 330 28 0.039 0.44 <0.013 <0.013 <0.013 0.086

MW-4 7/19/2011 250 260 26 0.04 0.45 <0.013 <0.013 <0.013 0.04

MW-4 9/7/2011 320 320 26 0.034 0.37 <0.013 <0.013 <0.013 0.052

140



MW-4 9/16/2011 320 320 27 0.041 0.41 <0.013 <0.013 <0.013 0.055

MW-4 9/22/2011 330 330 26 <0.0041 0.3 <0.013 <0.013 <0.013 <0.015

MW-4 9/28/2011 320 320 18 0.044 0.52 <0.013 <0.013 <0.018 <0.015

MW-4 10/19/2011 310 310 22 0.042 0.41 <0.013 <0.013 <0.013 0.034

MW-4 11/9/2011 24 0.035 0.6 <1.4

MW-4 11/10/2011 310 310 22 0.04 0.42 <0.013 <0.013 <0.013 0.05

MW-4 12/1/2011 300 300 24 0.034 0.57 <0.018 <0.012 <0.018 <1.4

MW-4 3/14/2012 320 320 26 0.025 0.59 <0.018 <0.012 <0.018 <1.4

MW-4 4/11/2012 360 360 26 <0.067 0.6 <0.018 <0.012 <0.018 1.7

MW-4 10/4/2012 25 8.6

MW-4 1/15/2013 620 620 28 <0.067 0.25 <0.018 <0.018 <0.018 <1.4

PW-1 2/12/2010 310 310 27 0.03 0.48 <0.018 <0.01 <0.018 <1.6

PW-1 6/28/2010 310 330 25 0.045 0.45 <0.018 <0.01 3.7

PW-1 7/30/2010 320 330 26 0.044 0.5 <0.018 <0.0087 5.2

PW-1 8/25/2010 330 340 24 0.33 0.42 <0.018 <0.0087 <0.018 9.4

PW-1 12/4/2010 310 320 22 0.038 0.54 <0.013 <0.0087 <0.013 0.74

PW-1 12/27/2010 310 320 25 0.034 0.48 0.033 0.035 <0.013 0.55

PW-1 1/25/2011 310 320 24 0.036 0.5 <0.013 <0.0087 <0.013 1.8

PW-1 2/24/2011 310 320 25 0.19 0.52 <0.013 <0.0087 <0.013 3.3

141

Table A-4. Trace element data.

Well Date Sb As Be Cd Cr Co

mg/L mg/L mg/L mg/L mg/L mg/L

BG-1 9/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

BG-1 10/6/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 10/29/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 12/3/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 12/27/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 1/25/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 2/23/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 5/18/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 6/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 7/18/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 9/7/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 9/14/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 9/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 9/28/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 10/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 11/10/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 12/1/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 3/15/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 4/11/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 10/4/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

BG-1 1/14/2013 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 9/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 12/3/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 12/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 1/26/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 2/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

IW-1 10/5/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 2/12/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0005

MW-1 6/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 7/30/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0005

MW-1 8/25/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

142



MW-1 10/5/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 10/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 12/3/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 12/29/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/26/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 2/23/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 5/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 6/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 7/19/2011 0.003 <0.0013 <0.00025 <0.000095 <0.0025 0.0005

MW-1 9/8/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 9/16/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 9/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 9/28/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 10/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 11/10/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 12/1/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0003

MW-1 1/6/2012 <0.0023 <0.0013 <0.000095 <0.0025 0.0003

MW-1 1/9/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 1/11/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/13/2012 0.002 <0.0013 <0.00025 <0.000095 <0.0025

MW-1 1/16/2012 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/18/2012 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/20/2012 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/23/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/30/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 2/1/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 2/3/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 2/6/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 2/8/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 2/10/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-1 2/13/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0009

MW-1 2/15/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 2/17/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

143



MW-1 2/29/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 0.0002

MW-1 3/2/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 0.0002

MW-1 3/5/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

MW-1 3/7/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 3/9/2012 0.002 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 3/12/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 3/14/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 3/19/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 3/21/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 <0.00015

MW-1 3/23/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 3/26/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-1 4/2/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 4/9/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 4/12/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 4/16/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 10/5/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-1 1/15/2013 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 2/12/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 6/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0003

MW-2 7/30/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0006

MW-2 8/25/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 10/5/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 10/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 12/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 12/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 1/26/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 2/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 5/20/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 6/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 7/19/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-2 9/7/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 9/15/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 9/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

144



MW-2 9/28/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-2 10/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.004 <0.00015

MW-2 11/10/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-2 11/16/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0003

MW-2 12/1/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0003

MW-2 12/7/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0003

MW-2 12/14/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-2 1/6/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0004

MW-2 1/9/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0004

MW-2 1/11/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 0.001

MW-2 1/13/2012 0.002 <0.0013 <0.00025 <0.000095 0.004 0.0014

MW-2 1/16/2012 0.002 <0.0013 <0.00025 <0.000095 0.005 0.0004

MW-2 1/18/2012 0.002 <0.0013 <0.00025 <0.000095 0.007 0.0003

MW-2 1/20/2012 0.002 <0.0013 <0.00025 <0.000095 0.006 0.0004

MW-2 1/23/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.006 0.0005

MW-2 1/27/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0013

MW-2 1/30/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0012

MW-2 2/1/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.001

MW-2 2/3/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0007

MW-2 2/6/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.009 0.0013

MW-2 2/8/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.008 0.001

MW-2 2/10/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0006

MW-2 2/13/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-2 2/15/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.006 0.0003

MW-2 2/17/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.009 0.0006

MW-2 2/29/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0005

MW-2 3/2/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.006 0.0003

MW-2 3/5/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.008 0.0006

MW-2 3/7/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.005 0.0002

MW-2 3/9/2012 0.002 <0.0013 <0.00025 <0.000095 0.005 0.0002

MW-2 3/12/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

MW-2 3/14/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

MW-2 3/19/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

145



MW-2 3/21/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

MW-2 3/23/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.006 0.0002

MW-2 3/26/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.005 0.0002

MW-2 4/2/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.005 0.0002

MW-2 4/9/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.005 0.0003

MW-2 4/11/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.004 0.0002

MW-2 4/16/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.005 0.0002

MW-2 10/4/2012 <0.0023 <0.0013 <0.00025 <0.000095 0.003 0.0002

MW-2 1/14/2013 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-3 9/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0004

MW-3 10/5/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 12/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 12/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 1/24/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 2/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 5/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 6/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 7/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 7/20/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 7/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 8/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 8/23/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 8/25/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 8/27/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 8/29/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 9/1/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 9/8/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 9/15/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 9/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 9/28/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/5/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/12/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.007 0.0003

146



MW-3 10/17/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/24/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/26/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/28/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-3 10/31/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.003 <0.00015

MW-3 11/2/2011 <0.0023 <0.0013 <0.00025 0.00024 0.004 <0.00015

MW-3 11/4/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.005 <0.00015

MW-3 11/10/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.01 0.0002

MW-3 11/11/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.013 0.0002

MW-3 11/14/2011 <0.0023 <0.0013 <0.00025 <0.000095 0.013 0.0002

MW-3 11/16/2011 <0.0023 <0.0013 0.0003 <0.000095 0.013 0.0002

MW-3 11/18/2011 <0.0023 <0.0013 0.0003 <0.000095 0.012 0.0002

MW-3 11/21/2011 <0.0023 <0.0013 0.0003 <0.000095 0.009 0.0004

MW-3 11/23/2011 <0.0023 <0.0013 0.0003 <0.000095 0.009 0.0003

MW-3 11/25/2011 <0.0023 <0.0013 0.0003 <0.000095 0.009 0.0004

MW-3 11/28/2011 <0.0023 <0.0013 0.0003 <0.000095 0.007 0.0003

MW-3 11/30/2011 <0.0023 <0.0013 0.0003 <0.000095 0.006 0.0004

MW-3 12/2/2011 <0.0023 <0.0013 0.0003 <0.000095 0.006 0.0003

MW-3 12/5/2011 <0.0023 <0.0013 0.0003 <0.000095 0.006 0.0002

MW-3 12/7/2011 0.003 <0.0013 0.0003 <0.000095 0.006 0.0003

MW-3 12/14/2011 <0.0023 <0.0013 0.0004 <0.000095 0.004 0.0006

MW-3 1/4/2012 <0.0023 <0.0013 0.0003 <0.000095 0.004 0.0004

MW-3 3/15/2012 <0.0023 <0.0013 0.0007 <0.000095 0.004 0.0003

MW-3 4/12/2012 <0.0023 <0.0013 0.0007 <0.000095 0.005 0.0004

MW-3 10/5/2012 <0.0023 <0.0013 0.0004 <0.000095 0.005 0.0004

MW-3 1/15/2013 <0.0023 <0.0013 0.0005 <0.000095 0.004 0.0003

MW-4 9/2/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 10/5/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 10/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 12/3/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 12/29/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

147



MW-4 1/25/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 2/23/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 5/20/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 6/21/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 7/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-4 9/7/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 9/16/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 9/22/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0002

MW-4 9/28/2011 0.002 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 10/19/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 11/10/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 12/1/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 3/14/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 3/19/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 3/21/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 3/23/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 3/26/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 4/2/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 4/9/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 4/11/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 4/16/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

MW-4 10/4/2012 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.0044

MW-4 1/15/2013 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 0.012

PW-1 2/12/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 6/28/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 7/30/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 8/25/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 12/4/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 12/27/2010 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 1/25/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

PW-1 2/24/2011 <0.0023 <0.0013 <0.00025 <0.000095 <0.0025 <0.00015

148

Well Date Cu Pb Hg Mo Ni

mg/L mg/L mg/L mg/L mg/L

BG-1 9/2/2010 <0.0011 0.0005 <0.00007 0.007 <0.002

BG-1 10/6/2010 <0.0011 <0.0002 0.00013 0.005 <0.002

BG-1 10/29/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

BG-1 12/3/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

BG-1 12/27/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

BG-1 1/25/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

BG-1 2/23/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

BG-1 5/18/2011 <0.0011 <0.0002 <0.00007 0.007 <0.002

BG-1 6/22/2011 <0.0011 <0.0002 <0.00007 0.007 <0.002

BG-1 7/18/2011 <0.0011 <0.0002 <0.00007 0.008 <0.002

BG-1 9/7/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

BG-1 9/14/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

BG-1 9/21/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

BG-1 9/28/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

BG-1 10/19/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

BG-1 11/10/2011 <0.0011 <0.0002 0.00008 0.004 <0.002

BG-1 12/1/2011 <0.0011 0.0021 <0.00007 0.004 <0.002

BG-1 3/15/2012 <0.0011 <0.0002 <0.00007 0.003 <0.002

BG-1 4/11/2012 <0.0011 0.0008 <0.00007 0.003 <0.002

BG-1 10/4/2012 <0.0011 <0.0002 <0.00007 0.004 0.002

BG-1 1/14/2013 <0.0011 <0.0002 <0.00007 0.004 <0.002

IW-1 9/2/2010 <0.0011 <0.0002 <0.00007 0.008 <0.002

IW-1 12/3/2010 0.002 0.0003 <0.00007 0.007 <0.002

IW-1 12/28/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

IW-1 1/26/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

IW-1 2/22/2011 <0.0011 <0.0002 <0.00007 0.006 <0.002

IW-1 10/5/2012 <0.0011 <0.0002 <0.00007 0.002 0.003

MW-1 2/12/2010 <0.0011 0.0005 <0.00007 0.004 <0.002

MW-1 6/28/2010 <0.0011 <0.0002 <0.00007 0.011 <0.002

MW-1 7/30/2010 <0.0011 <0.0002 <0.00007 0.009 <0.002

MW-1 8/25/2010 <0.0011 0.0004 <0.00007 0.008 <0.002

149



MW-1 10/5/2010 <0.0011 <0.0002 0.00015 0.007 <0.002

MW-1 10/28/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-1 12/3/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-1 12/29/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-1 1/26/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-1 2/23/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-1 5/19/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-1 6/21/2011 <0.0011 <0.0002 0.00013 0.004 <0.002

MW-1 7/19/2011 <0.0011 <0.0002 <0.00007 0.013 0.037

MW-1 9/8/2011 <0.0011 <0.0002 <0.00007 0.005 0.004

MW-1 9/16/2011 <0.0011 <0.0002 <0.00007 0.007 0.006

MW-1 9/22/2011 <0.0011 <0.0002 <0.00007 0.006 0.004

MW-1 9/28/2011 <0.0011 <0.0002 <0.00007 0.006 0.007

MW-1 10/19/2011 <0.0011 <0.0002 <0.00007 0.008 0.008

MW-1 11/10/2011 <0.0011 <0.0002 <0.00007 0.008 0.012

MW-1 12/1/2011 <0.0011 <0.0002 <0.00007 0.012 0.015

MW-1 1/6/2012 <0.0011 <0.0002 <0.00007 0.01 0.012

MW-1 1/9/2012 <0.0011 <0.0002 0.00008 0.008 0.009

MW-1 1/11/2012 <0.0011 <0.0002 <0.00007 0.005 0.006

MW-1 1/13/2012 <0.0011 0.0003 <0.00007 0.005 0.006

MW-1 1/16/2012 <0.0011 <0.0002 <0.00007 0.005 0.007

MW-1 1/18/2012 <0.0011 <0.0002 <0.00007 0.004 0.007

MW-1 1/20/2012 <0.0011 <0.0002 <0.00007 0.005 0.008

MW-1 1/23/2012 <0.0011 <0.0002 <0.00007 0.005 0.004

MW-1 1/30/2012 <0.0011 <0.0002 <0.00007 0.005 0.007

MW-1 2/1/2012 <0.0011 <0.0002 <0.00007 0.003 0.005

MW-1 2/3/2012 <0.0011 <0.0002 <0.00007 0.004 0.007

MW-1 2/6/2012 <0.0011 <0.0002 <0.00007 0.008 0.008

MW-1 2/8/2012 <0.0011 <0.0002 <0.00007 0.005 0.008

MW-1 2/10/2012 0.002 <0.0002 0.00023 0.005 0.008

MW-1 2/13/2012 <0.0011 <0.0002 <0.00007 0.003 0.061

MW-1 2/15/2012 <0.0011 <0.0002 <0.00007 0.002 0.004

MW-1 2/17/2012 <0.0011 <0.0002 <0.00007 0.002 0.006

150



MW-1 2/29/2012 <0.0011 <0.0002 <0.00007 0.002 0.013

MW-1 3/2/2012 <0.0011 <0.0002 0.0001 0.002 0.009

MW-1 3/5/2012 <0.0011 <0.0002 0.00017 0.002 0.013

MW-1 3/7/2012 <0.0011 <0.0002 0.00014 <0.0015 0.005

MW-1 3/9/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-1 3/12/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-1 3/14/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.007

MW-1 3/19/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-1 3/21/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.008

MW-1 3/23/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.007

MW-1 3/26/2012 <0.0011 0.0008 <0.00007 <0.0015 0.007

MW-1 4/2/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.007

MW-1 4/9/2012 <0.0011 0.0002 <0.00007 <0.0015 0.006

MW-1 4/12/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.005

MW-1 4/16/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-1 10/5/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.005

MW-1 1/15/2013 <0.0011 <0.0002 <0.00007 <0.0015 0.002

MW-2 2/12/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-2 6/28/2010 <0.0011 <0.0002 <0.00007 0.007 <0.002

MW-2 7/30/2010 <0.0011 <0.0002 <0.00007 0.007 <0.002

MW-2 8/25/2010 <0.0011 0.0009 <0.00007 0.008 <0.002

MW-2 10/5/2010 <0.0011 <0.0002 0.00017 0.008 <0.002

MW-2 10/28/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-2 12/2/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-2 12/28/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-2 1/26/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-2 2/22/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-2 5/20/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-2 6/21/2011 <0.0011 <0.0002 0.0001 0.005 <0.002

MW-2 7/19/2011 <0.0011 <0.0002 <0.00007 0.013 0.016

MW-2 9/7/2011 <0.0011 <0.0002 <0.00007 0.004 0.003

MW-2 9/15/2011 <0.0011 <0.0002 <0.00007 0.004 0.004

MW-2 9/21/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

151



MW-2 9/28/2011 <0.0011 <0.0002 <0.00007 0.004 0.003

MW-2 10/19/2011 <0.0011 <0.0002 <0.00007 0.006 0.009

MW-2 11/10/2011 <0.0011 <0.0002 <0.00007 0.009 0.016

MW-2 11/16/2011 <0.0011 <0.0002 <0.00007 0.008 0.014

MW-2 12/1/2011 <0.0011 <0.0002 <0.00007 0.01 0.015

MW-2 12/7/2011 <0.0011 <0.0002 <0.00007 0.01 0.013

MW-2 12/14/2011 <0.0011 <0.0002 <0.00007 0.007 0.008

MW-2 1/6/2012 <0.0011 <0.0002 <0.00007 0.002 0.02

MW-2 1/9/2012 <0.0011 <0.0002 <0.00007 0.002 0.022

MW-2 1/11/2012 <0.0011 <0.0002 <0.00007 0.003 0.05

MW-2 1/13/2012 <0.0011 0.0002 <0.00007 0.005 0.078

MW-2 1/16/2012 <0.0011 <0.0002 <0.00007 0.002 0.018

MW-2 1/18/2012 <0.0011 <0.0002 <0.00007 0.002 0.017

MW-2 1/20/2012 <0.0011 <0.0002 <0.00007 0.002 0.022

MW-2 1/23/2012 <0.0011 <0.0002 <0.00007 0.003 0.029

MW-2 1/27/2012 <0.0011 <0.0002 <0.00007 0.006 0.09

MW-2 1/30/2012 <0.0011 <0.0002 <0.00007 0.005 0.092

MW-2 2/1/2012 <0.0011 <0.0002 <0.00007 0.004 0.079

MW-2 2/3/2012 <0.0011 <0.0002 <0.00007 0.002 0.047

MW-2 2/6/2012 <0.0011 <0.0002 <0.00007 0.005 0.1

MW-2 2/8/2012 <0.0011 <0.0002 <0.00007 0.004 0.078

MW-2 2/10/2012 <0.0011 <0.0002 <0.00007 0.003 0.041

MW-2 2/13/2012 <0.0011 <0.0002 <0.00007 0.004 0.007

MW-2 2/15/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.02

MW-2 2/17/2012 <0.0011 <0.0002 <0.00007 0.002 0.039

MW-2 2/29/2012 <0.0011 <0.0002 0.00016 0.002 0.032

MW-2 3/2/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.015

MW-2 3/5/2012 <0.0011 <0.0002 <0.00007 0.003 0.043

MW-2 3/7/2012 <0.0011 <0.0002 <0.00007 0.002 0.01

MW-2 3/9/2012 <0.0011 <0.0002 <0.00007 0.002 0.01

MW-2 3/12/2012 <0.0011 <0.0002 <0.00007 0.002 0.008

MW-2 3/14/2012 <0.0011 <0.0002 <0.00007 0.002 0.006

MW-2 3/19/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

152



MW-2 3/21/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-2 3/23/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.007

MW-2 3/26/2012 <0.0011 0.0005 <0.00007 <0.0015 0.005

MW-2 4/2/2012 <0.0011 0.0002 <0.00007 <0.0015 0.004

MW-2 4/9/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.009

MW-2 4/11/2012 <0.0011 0.0004 <0.00007 <0.0015 0.005

MW-2 4/16/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.006

MW-2 10/4/2012 <0.0011 <0.0002 <0.0015 0.004

MW-2 1/14/2013 <0.0011 <0.0002 <0.00007 <0.0015 0.002

MW-3 9/2/2010 <0.0011 0.0009 <0.00007 0.011 <0.002

MW-3 10/5/2010 <0.0011 <0.0002 0.00012 0.002 <0.002

MW-3 10/28/2010 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 12/2/2010 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 12/28/2010 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 1/24/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-3 2/22/2011 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 5/19/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 6/21/2011 <0.0011 <0.0002 0.00017 0.004 <0.002

MW-3 7/19/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

MW-3 7/20/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 7/21/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 8/21/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-3 8/23/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-3 8/25/2011 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 8/27/2011 <0.0011 <0.0002 <0.00007 0.004 0.002

MW-3 8/29/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 9/1/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

MW-3 9/8/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 9/15/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-3 9/22/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-3 9/28/2011 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-3 10/5/2011 <0.0011 0.0007 <0.00007 0.003 0.003

MW-3 10/12/2011 0.002 <0.0002 <0.00007 0.004 0.006

153



MW-3 10/17/2011 <0.0011 <0.0002 <0.00007 0.003 0.002

MW-3 10/19/2011 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 10/21/2011 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 10/24/2011 <0.0011 <0.0002 <0.00007 0.002 <0.002

MW-3 10/26/2011 <0.0011 <0.0002 0.00012 0.003 <0.002

MW-3 10/28/2011 0.001 <0.0002 <0.00007 0.002 0.002

MW-3 10/31/2011 <0.0011 <0.0002 <0.00007 0.003 0.004

MW-3 11/2/2011 <0.0011 <0.0002 <0.00007 0.002 0.003

MW-3 11/4/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.003

MW-3 11/10/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.005

MW-3 11/11/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.003

MW-3 11/14/2011 <0.0011 <0.0002 <0.00007 <0.0015 <0.002

MW-3 11/16/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.004

MW-3 11/18/2011 <0.0011 <0.0002 <0.00007 <0.0015 <0.002

MW-3 11/21/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.013

MW-3 11/23/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.009

MW-3 11/25/2011 <0.0011 <0.0002 0.00023 <0.0015 0.009

MW-3 11/28/2011 <0.0011 <0.0002 0.00007 <0.0015 0.009

MW-3 11/30/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.018

MW-3 12/2/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.004

MW-3 12/5/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.005

MW-3 12/7/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.009

MW-3 12/14/2011 <0.0011 <0.0002 <0.00007 <0.0015 0.026

MW-3 1/4/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.016

MW-3 3/15/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.007

MW-3 4/12/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.012

MW-3 10/5/2012 <0.0011 <0.0002 <0.00007 <0.0015 0.014

MW-3 1/15/2013 <0.0011 <0.0002 <0.00007 <0.0015 0.009

MW-4 9/2/2010 <0.0011 0.0002 <0.00007 0.003 <0.002

MW-4 10/5/2010 <0.0011 <0.0002 0.00019 0.01 <0.002

MW-4 10/28/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-4 12/3/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

MW-4 12/29/2010 <0.0011 <0.0002 <0.00007 0.004 <0.002

154



MW-4 1/25/2011 <0.0011 <0.0002 <0.00007 0.005 <0.002

MW-4 2/23/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 5/20/2011 <0.0011 <0.0002 <0.00007 0.006 <0.002

MW-4 6/21/2011 <0.0011 <0.0002 <0.00007 0.006 <0.002

MW-4 7/19/2011 <0.0011 <0.0002 <0.00007 0.01 0.008

MW-4 9/7/2011 <0.0011 <0.0002 <0.00007 0.003 0.002

MW-4 9/16/2011 <0.0011 <0.0002 <0.00007 0.005 0.006

MW-4 9/22/2011 <0.0011 <0.0002 <0.00007 0.006 0.003

MW-4 9/28/2011 <0.0011 <0.0002 <0.00007 0.004 0.003

MW-4 10/19/2011 <0.0011 <0.0002 <0.00007 0.005 0.007

MW-4 11/10/2011 <0.0011 <0.0002 <0.00007 0.006 0.003

MW-4 12/1/2011 <0.0011 <0.0002 <0.00007 0.006 0.003

MW-4 3/14/2012 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 3/19/2012 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 3/21/2012 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 3/23/2012 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 3/26/2012 <0.0011 <0.0002 <0.00007 0.004 <0.002

MW-4 4/2/2012 0.001 0.0006 <0.00007 0.004 <0.002

MW-4 4/9/2012 <0.0011 0.0008 <0.00007 0.003 <0.002

MW-4 4/11/2012 <0.0011 0.0009 <0.00007 0.004 0.002

MW-4 4/16/2012 <0.0011 <0.0002 <0.00007 0.004 0.004

MW-4 10/4/2012 <0.0011 <0.0002 <0.00007 0.002 0.006

MW-4 1/15/2013 <0.0011 <0.0002 <0.00007 0.002 0.004

PW-1 2/12/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

PW-1 6/28/2010 <0.0011 <0.0002 <0.00007 0.014 <0.002

PW-1 7/30/2010 <0.0011 <0.0002 <0.00007 0.013 <0.002

PW-1 8/25/2010 <0.0011 0.0003 <0.00007 0.011 <0.002

PW-1 12/4/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

PW-1 12/27/2010 <0.0011 <0.0002 <0.00007 0.003 <0.002

PW-1 1/25/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

PW-1 2/24/2011 <0.0011 <0.0002 <0.00007 0.004 <0.002

155

Well Date P Se Ag Tl Zn


BG-1 9/2/2010 0.26 <0.001 <0.00025 <0.0005 <0.0083

BG-1 10/6/2010 0.29 <0.001 <0.00025 <0.0005 <0.0083

BG-1 10/29/2010 0.2 <0.001 <0.00025 <0.0005 <0.0083

BG-1 12/3/2010 0.24 <0.001 <0.00025 <0.0005 <0.0083

BG-1 12/27/2010 0.37 <0.001 <0.00025 <0.0005 <0.0083

BG-1 1/25/2011 0.3 0.001 <0.00025 <0.0005 <0.0083

BG-1 2/23/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

BG-1 5/18/2011 0.43 <0.001 <0.00025 <0.0005 <0.0083

BG-1 6/22/2011 0.33 <0.001 <0.00025 <0.0005 <0.0083

BG-1 7/18/2011 0.24 <0.001 <0.00025 <0.0005 <0.0083

BG-1 9/7/2011 0.3 <0.001 <0.00025 <0.0005 <0.0083

BG-1 9/14/2011 0.25 <0.001 <0.00025 <0.0005 <0.0083

BG-1 9/21/2011 0.35 <0.001 <0.00025 <0.0005 <0.0083

BG-1 9/28/2011 0.25 <0.001 <0.00025 <0.0005 <0.0083

BG-1 10/19/2011 0.32 <0.001 <0.00025 <0.0005 <0.0083

BG-1 11/10/2011 0.38 <0.001 <0.00025 <0.0005 <0.0083

BG-1 12/1/2011 0.28 <0.001 <0.00025 <0.0005 <0.0083

BG-1 3/15/2012 0.27 <0.001 <0.00025 <0.0005 <0.0083

BG-1 4/11/2012 0.24 <0.001 <0.00025 <0.0005 <0.0083

BG-1 10/4/2012 <0.001 <0.00025 <0.0005 <0.0083

BG-1 1/14/2013 0.17 <0.001 <0.00025 <0.0005 <0.0083

IW-1 9/2/2010 0.26 <0.001 <0.00025 <0.0005 <0.0083

IW-1 12/3/2010 0.27 <0.001 <0.00025 <0.0005 <0.0083

IW-1 12/28/2010 0.3 <0.001 <0.00025 <0.0005 <0.0083

IW-1 1/26/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

IW-1 2/22/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

IW-1 10/5/2012 <0.001 <0.00025 <0.0005 0.027

MW-1 2/12/2010 0.28 <0.001 <0.00025 <0.0005 0.013

MW-1 6/28/2010 0.44 <0.001 <0.00025 <0.0005 <0.0083

MW-1 7/30/2010 0.38 <0.001 <0.00025 <0.0005 <0.0083

MW-1 8/25/2010 0.46 <0.001 <0.00025 <0.0005 <0.0083

156



MW-1 10/5/2010 0.4 <0.001 <0.00025 <0.0005 <0.0083

MW-1 10/28/2010 0.19 <0.001 <0.00025 <0.0005 <0.0083

MW-1 12/3/2010 1.3 <0.001 <0.00025 <0.0005 <0.0083

MW-1 12/29/2010 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/26/2011 0.29 0.001 <0.00025 <0.0005 <0.0083

MW-1 2/23/2011 0.39 0.001 <0.00025 <0.0005 <0.0083

MW-1 5/19/2011 0.33 <0.001 <0.00025 <0.0005 <0.0083

MW-1 6/21/2011 0.32 <0.001 <0.00025 <0.0005 <0.0083

MW-1 7/19/2011 0.2 <0.001 <0.00025 <0.0005 0.028

MW-1 9/8/2011 0.21 <0.001 <0.00025 <0.0005 <0.0083

MW-1 9/16/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-1 9/22/2011 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-1 9/28/2011 0.17 <0.001 <0.00025 <0.0005 <0.0083

MW-1 10/19/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-1 11/10/2011 0.4 <0.001 <0.00025 <0.0005 <0.0083

MW-1 12/1/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/6/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/11/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/13/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/16/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/18/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/20/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/23/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/30/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/1/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/3/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/6/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/8/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/10/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/13/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/15/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 2/17/2012 <0.001 <0.00025 <0.0005 <0.0083

157



MW-1 2/29/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/2/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/5/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/7/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/12/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/14/2012 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/19/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/21/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/23/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 3/26/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 4/2/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 4/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 4/12/2012 0.34 <0.001 <0.00025 <0.0005 <0.0083

MW-1 4/16/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 10/5/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-1 1/15/2013 0.21 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/12/2010 0.3 <0.001 <0.00025 <0.0005 0.013

MW-2 6/28/2010 0.36 <0.001 <0.00025 <0.0005 <0.0083

MW-2 7/30/2010 0.38 <0.001 <0.00025 <0.0005 <0.0083

MW-2 8/25/2010 0.45 <0.001 <0.00025 <0.0005 <0.0083

MW-2 10/5/2010 0.44 <0.001 <0.00025 <0.0005 <0.0083

MW-2 10/28/2010 0.22 <0.001 <0.00025 <0.0005 <0.0083

MW-2 12/2/2010 0.21 <0.001 <0.00025 <0.0005 <0.0083

MW-2 12/28/2010 0.31 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/26/2011 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/22/2011 0.3 <0.001 <0.00025 <0.0005 <0.0083

MW-2 5/20/2011 0.34 <0.001 <0.00025 <0.0005 <0.0083

MW-2 6/21/2011 0.39 <0.001 <0.00025 <0.0005 <0.0083

MW-2 7/19/2011 0.24 <0.001 <0.00025 <0.0005 <0.0083

MW-2 9/7/2011 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-2 9/15/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-2 9/21/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

158



MW-2 9/28/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-2 10/19/2011 0.25 <0.001 <0.00025 <0.0005 <0.0083

MW-2 11/10/2011 0.41 <0.001 <0.00025 <0.0005 <0.0083

MW-2 11/16/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-2 12/1/2011 0.24 <0.001 <0.00025 <0.0005 <0.0083

MW-2 12/7/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-2 12/14/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/6/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/11/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/13/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/16/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/18/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/20/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/23/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/27/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/30/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/1/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/3/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/6/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/8/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/10/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/13/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/15/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/17/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 2/29/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/2/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/5/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/7/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/12/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/14/2012 0.24 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/19/2012 <0.001 <0.00025 <0.0005 <0.0083

159



MW-2 3/21/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/23/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 3/26/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 4/2/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 4/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 4/11/2012 0.27 <0.001 <0.00025 <0.0005 0.036

MW-2 4/16/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 10/4/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-2 1/14/2013 0.22 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/2/2010 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/5/2010 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/28/2010 0.18 <0.001 <0.00025 <0.0005 <0.0083

MW-3 12/2/2010 0.21 <0.001 <0.00025 <0.0005 <0.0083

MW-3 12/28/2010 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-3 1/24/2011 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-3 2/22/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-3 5/19/2011 0.3 <0.001 <0.00025 <0.0005 0.008

MW-3 6/21/2011 0.3 <0.001 <0.00025 <0.0005 <0.0083

MW-3 7/19/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

MW-3 7/20/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

MW-3 7/21/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-3 8/21/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-3 8/23/2011 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-3 8/25/2011 <0.019 <0.001 <0.00025 <0.0005 <0.0083

MW-3 8/27/2011 0.34 <0.001 <0.00025 <0.0005 <0.0083

MW-3 8/29/2011 0.3 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/1/2011 0.32 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/8/2011 0.2 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/15/2011 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/22/2011 0.3 <0.001 <0.00025 <0.0005 <0.0083

MW-3 9/28/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/5/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/12/2011 0.29 <0.001 <0.00025 <0.0005 <0.0083

160



MW-3 10/17/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/19/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/21/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/24/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/26/2011 0.26 <0.001 0.0003 <0.0005 <0.0083

MW-3 10/28/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/31/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/2/2011 0.24 <0.001 0.0007 <0.0005 <0.0083

MW-3 11/4/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/10/2011 0.36 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/11/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/14/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/16/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/18/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/21/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 11/23/2011 0.23 <0.001 0.0003 <0.0005 0.009

MW-3 11/25/2011 <0.001 0.0003 <0.0005 <0.0083

MW-3 11/28/2011 <0.001 0.0003 <0.0005 <0.0083

MW-3 11/30/2011 0.25 <0.001 <0.00025 <0.0005 0.008

MW-3 12/2/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 12/5/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 12/7/2011 <0.001 <0.00025 <0.0005 <0.0083

MW-3 12/14/2011 <0.001 <0.00025 <0.0005 0.009

MW-3 1/4/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-3 3/15/2012 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-3 4/12/2012 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-3 10/5/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-3 1/15/2013 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-4 9/2/2010 0.26 <0.001 <0.00025 <0.0005 0.01

MW-4 10/5/2010 0.56 <0.001 <0.00025 <0.0005 <0.0083

MW-4 10/28/2010 0.2 <0.001 <0.00025 <0.0005 <0.0083

MW-4 12/3/2010 0.22 <0.001 <0.00025 <0.0005 <0.0083

MW-4 12/29/2010 0.31 <0.001 <0.00025 <0.0005 <0.0083

161



MW-4 1/25/2011 0.29 <0.001 <0.00025 <0.0005 <0.0083

MW-4 2/23/2011 0.34 <0.001 <0.00025 <0.0005 <0.0083

MW-4 5/20/2011 0.41 <0.001 <0.00025 <0.0005 <0.0083

MW-4 6/21/2011 0.39 <0.001 <0.00025 <0.0005 <0.0083

MW-4 7/19/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

MW-4 9/7/2011 0.2 <0.001 <0.00025 <0.0005 <0.0083

MW-4 9/16/2011 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-4 9/22/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

MW-4 9/28/2011 0.26 <0.001 <0.00025 <0.0005 <0.0083

MW-4 10/19/2011 0.24 <0.001 <0.00025 <0.0005 <0.0083

MW-4 11/10/2011 0.37 <0.001 <0.00025 <0.0005 <0.0083

MW-4 12/1/2011 0.24 <0.001 <0.00025 <0.0005 <0.0083

MW-4 3/14/2012 0.28 <0.001 <0.00025 <0.0005 <0.0083

MW-4 3/19/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 3/21/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 3/23/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 3/26/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 4/2/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 4/9/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 4/11/2012 0.25 <0.001 <0.00025 <0.0005 <0.0083

MW-4 4/16/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 10/4/2012 <0.001 <0.00025 <0.0005 <0.0083

MW-4 1/15/2013 0.21 <0.001 <0.00025 <0.0005 <0.0083

PW-1 2/12/2010 0.32 <0.001 <0.00025 <0.0005 0.014

PW-1 6/28/2010 0.56 <0.001 <0.00025 <0.0005 <0.0083

PW-1 7/30/2010 0.25 <0.001 <0.00025 <0.0005 <0.0083

PW-1 8/25/2010 0.49 <0.001 <0.00025 <0.0005 <0.0083

PW-1 12/4/2010 0.23 <0.001 <0.00025 <0.0005 <0.0083

PW-1 12/27/2010 0.31 <0.001 <0.00025 <0.0005 <0.0083

PW-1 1/25/2011 0.31 <0.001 <0.00025 <0.0005 <0.0083

PW-1 2/24/2011 0.27 <0.001 <0.00025 <0.0005 <0.0083

162

Table A-5. Dissolved organics.

Well Date

Acetic

Acid

Dissolved

Organic

Carbon

Lactic

Acid

Propionic

Acid Pyruvic Acid


BG-1 9/2/2010 <0.24 0.74 <2.2 <0.093 <0.21

BG-1 10/6/2010 0.87 1.9 <2.2 <0.093 <0.21

BG-1 10/29/2010 0.72 2.1 <2.2 <0.093 <0.21

BG-1 12/3/2010 1.4 2 <2.2 <0.093 <0.21

BG-1 12/27/2010 <0.24 1.6 <2.2 <0.093 <0.21

BG-1 1/25/2011 0.37 1.9 <2.2 <0.093 <0.21

BG-1 2/23/2011 0.57 2.2 <2.2 0.093 0.21

BG-1 5/18/2011 2.4 3.1 <2.2 <0.093 <0.21

BG-1 6/22/2011 1.7 2.5 <2.2 <0.093 <0.21

BG-1 7/18/2011 2.4 2.6 <2.2 <0.093 <0.21

BG-1 9/7/2011 1.4 2.4 <2.2 <0.093 <0.21

BG-1 9/14/2011 0.38 2.2 <2.2 <0.093 <0.21

BG-1 9/21/2011 0.35 2 <2.2 <0.093 <0.21

BG-1 9/28/2011 0.24 2.2 <2.2 <0.093 <0.21

BG-1 10/19/2011 0.87 2.1 <2.2 0.097 <0.21

BG-1 11/10/2011 <0.24 1.3 <2.2 <0.093 <0.21

BG-1 12/1/2011 <0.24 1.8 <2.2 <0.093 <0.21

BG-1 3/15/2012 <0.24 1.3 <2.2 <0.093 <0.21

BG-1 4/11/2012 <0.24 2.7 <2.2 <0.093 <0.21

BG-1 1/14/2013 <0.24 6.2 <2.2 <0.093 <0.21

IW-1 9/2/2010 <0.24 0.8 <2.2 <0.093 <0.21

IW-1 12/3/2010 <0.24 2.6 <2.2 <0.093 <0.21

IW-1 12/28/2010 <0.24 1.7 <2.2 <0.093 <0.21

IW-1 1/26/2011 1.1 2.4 <2.2 <0.093 <0.21

IW-1 2/22/2011 0.61 2.8 <2.2 0.093 0.21

MW-1 2/12/2010

2

MW-1 6/28/2010 3.6 4.1

MW-1 7/30/2010 1.6 3.1

MW-1 8/25/2010 1.6 2.4

MW-1 10/5/2010 0.84 1.9 <2.2 <0.093 <0.21

MW-1 10/28/2010 <0.24 1.5 <2.2 <0.093 <0.21

MW-1 12/3/2010 <0.24 1.3 <2.2 <0.093 <0.21

MW-1 12/29/2010 <0.24 1.5 <2.2 <0.093 <0.21

MW-1 1/26/2011 <0.24 1.6 <2.2 <0.093 <0.21

MW-1 2/23/2011 <0.24 2 <2.2 0.093 0.21

MW-1 5/19/2011 <0.24 1.5 <2.2 <0.093 <0.21

MW-1 6/21/2011 0.24 1.4 <2.2 <0.093 <0.21

MW-1 7/19/2011 <0.24 3.2 <2.2 <0.093 <0.21

MW-1 9/8/2011 <0.24 2.1 6.1 <0.093 <0.21

MW-1 9/16/2011 <0.24 2.2 <2.2 <0.093 <0.21

MW-1 9/22/2011 <0.24 1.8 <2.2 <0.093 <0.21

163

Well Date

Acetic

Acid

Dissolved

Organic

Carbon

Lactic

Acid

Propionic

Acid Pyruvic Acid


MW-1 9/28/2011 <0.24 1.9 <2.2 <0.093 <0.21

MW-1 10/19/2011 <0.24 2.5 <2.2 <0.093 <0.21

MW-1 11/10/2011 <0.24 1.5 <2.2 <0.093 <0.21

MW-1 12/1/2011 <0.24 1.9 <2.2 <0.093 <0.21

MW-1 3/14/2012 <0.24 4.4 <2.2 <0.093 <0.21

MW-1 4/12/2012 <0.24 11 <2.2 <0.093 <0.21

MW-1 1/15/2013 <0.24 9 2.4 <0.093 <0.21

MW-2 2/12/2010

2

MW-2 6/28/2010 2.7 2.9

MW-2 7/30/2010 0.24 2

MW-2 8/25/2010 0.3 2.3

MW-2 10/5/2010 <0.24 1.6 <2.2 <0.093 <0.21

MW-2 10/28/2010 <0.24 1.5 <2.2 <0.093 <0.21

MW-2 12/2/2010 <0.24 1.2 <2.2 <0.093 <0.21

MW-2 12/28/2010 <0.24 1.5 <2.2 <0.093 <0.21

MW-2 1/26/2011 <0.24 1.6 <2.2 <0.093 <0.21

MW-2 2/22/2011 <0.24 1.9 <2.2 0.093 0.21

MW-2 5/20/2011 <0.24 1.5 <2.2 <0.093 <0.21

MW-2 6/21/2011 0.24 1.5 <2.2 <0.093 <0.21

MW-2 7/19/2011 <0.24 4.6 <2.2 <0.093 <0.21

MW-2 9/7/2011 <0.24 2.2 <2.2 <0.093 <0.21

MW-2 9/15/2011 <0.24 2 <2.2 <0.093 <0.21

MW-2 9/21/2011 <0.24 1.9 <2.2 <0.093 <0.21

MW-2 9/28/2011 <0.24 1.9 <2.2 <0.093 <0.21

MW-2 10/19/2011 <0.24 2.2 <2.2 <0.093 <0.21

MW-2 11/10/2011 <0.24 1.3 <2.2 <0.093 <0.21

MW-2 11/16/2011 <0.24 <0.5 <2.2 <0.093 <0.21

MW-2 12/1/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-2 3/14/2012 <0.24 5.9 <2.2 <0.093 <0.21

MW-2 4/11/2012 <0.24 7.5 <2.2 <0.093 <0.21

MW-2 1/14/2013 <0.24 16 <2.2 <0.093 <0.21

MW-3 9/2/2010 0.42 1.4 <2.2 <0.093 <0.21

MW-3 10/5/2010 <0.24 1.3 <2.2 <0.093 <0.21

MW-3 10/28/2010 <0.24 1.5 <2.2 <0.093 <0.21

MW-3 12/2/2010 <0.24 1.2 <2.2 <0.093 <0.21

MW-3 12/28/2010 <0.24 1.6 <2.2 <0.093 <0.21

MW-3 1/24/2011 <0.24 1.8 <2.2 <0.093 <0.21

MW-3 2/22/2011 <0.24 1.9 <2.2 0.093 0.21

MW-3 5/19/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 6/21/2011 1.2 3 <2.2 <0.093 <0.21

MW-3 7/19/2011 1.3 2.6 <2.2 <0.093 <0.21

MW-3 7/20/2011 0.3 2.2 <2.2 <0.093 <0.21

164

Well Date

Acetic

Acid

Dissolved

Organic

Carbon

Lactic

Acid

Propionic

Acid Pyruvic Acid


MW-3 7/21/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-3 8/21/2011 <0.24 1.8 <2.2 <0.093 <0.21

MW-3 8/23/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-3 8/25/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 8/27/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-3 8/29/2011 <0.24 1.9 <2.2 <0.093 <0.21

MW-3 9/1/2011 0.61 2 <2.2 <0.093 <0.21

MW-3 9/8/2011 0.42 2.4 <2.2 <0.093 <0.21

MW-3 9/15/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-3 9/22/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 9/28/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 10/5/2011 <0.24 2.3 <2.2 <0.093 <0.21

MW-3 10/12/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 10/19/2011 <0.24 2.4 <2.2 <0.093 <0.21

MW-3 10/26/2011 <0.24 2 <2.2 <0.093 <0.21

MW-3 11/2/2011

2.5

MW-3 11/10/2011 <0.24 3.4 <2.2 <0.093 <0.21

MW-3 11/16/2011 <0.24 1.4 <2.2 <0.093 <0.21

MW-3 11/23/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-3 11/30/2011 <0.24 3.2 <2.2 <0.093 <0.21

MW-3 3/15/2012 <0.24 5.7 <2.2 <0.093 <0.21

MW-3 4/12/2012 <0.24 9.8 <2.2 <0.093 <0.21

MW-3 1/15/2013 0.24 17 6.9 <0.093 <0.21

MW-4 9/2/2010 <0.24 1.3 <2.2 <0.093 <0.21

MW-4 10/5/2010 7.2 6.1 <2.2 <0.093 <0.21

MW-4 10/28/2010 <0.24 1.6 <2.2 <0.093 <0.21

MW-4 12/3/2010 <0.24 1.8 <2.2 <0.093 <0.21

MW-4 12/29/2010 <0.24 1.7 <2.2 <0.093 <0.21

MW-4 1/25/2011 0.39 2.2 <2.2 <0.093 <0.21

MW-4 2/23/2011 2.1 3 <2.2 0.093 0.21

MW-4 5/20/2011 <0.24 2 <2.2 <0.093 <0.21

MW-4 6/21/2011 0.24 1.7 <2.2 <0.093 <0.21

MW-4 7/19/2011 <0.24 3.7 <2.2 <0.093 <0.21

MW-4 9/7/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-4 9/16/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-4 9/22/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-4 9/28/2011 <0.24 21 <2.2 <0.093 <0.21

MW-4 10/19/2011 <0.24 2.3 <2.2 <0.093 <0.21

MW-4 11/10/2011 <0.24 1.5 5.2 <0.093 <0.21

MW-4 12/1/2011 <0.24 2.1 <2.2 <0.093 <0.21

MW-4 3/14/2012 <0.24 1.6 <2.2 <0.093 <0.21

MW-4 4/11/2012 <0.24 3 <2.2 <0.093 <0.21

165

Well Date

Acetic

Acid

Dissolved

Organic

Carbon

Lactic

Acid

Propionic

Acid Pyruvic Acid


MW-4 1/15/2013 <0.24 11 <2.2 <0.093 <0.21

PW-1 2/12/2010

1.9

PW-1 6/28/2010 16 9.1

PW-1 7/30/2010 2.1 7.1

PW-1 8/25/2010 4.7 1.9

PW-1 12/4/2010 <0.24 1.6 <2.2 <0.093 <0.21

PW-1 12/27/2010 <0.24 1.7 <2.2 <0.093 <0.21

PW-1 1/25/2011 <0.24 1.9 <2.2 <0.093 <0.21

PW-1 2/24/2011 <0.24 2.1 <2.2 0.093 0.21

166

Table A-6. Dissolved gas measurements.

Well Date NH3 as N Carbon

Dioxide

Carbon

Monoxide

Oxygen Ethane Ethylene Methane Nitrogen Sulfide, Lab

mg/L ug/L ug/L ug/L ug/L ug/L ug/L ug/L mg/L

BG-1 9/2/2010 0.3 51 <1.1

BG-1 10/6/2010 0.35 39 <0.17 <0.11 11 <1.1

BG-1 10/29/2010 0.27 47 <0.17 <0.11 20 1.3

BG-1 12/3/2010 0.34 56 0.19 <0.11 50 <1.1

BG-1 12/27/2010 0.38 63 <0.17 <0.11 24 <1.1

BG-1 1/25/2011 0.25 57 0.2 <0.11 45 <1.1

BG-1 2/23/2011 0.28 68 <0.17 <0.11 38 <1.1

BG-1 5/18/2011 0.32 49 0.2 0.13 150 1.6

BG-1 6/22/2011 0.28 40 <0.17 <0.11 240 <1.1

BG-1 7/18/2011 0.41 36 0.32 <0.11 160 <1.1

BG-1 9/7/2011 0.43 35 <13 0.25 <0.11 140 4800 <1.1

BG-1 9/14/2011 0.32 55 <13 0.23 <0.11 130 4600 <1.1

BG-1 9/21/2011 0.31 52 <13 <0.17 <0.11 110 7000 <1.1

BG-1 9/28/2011 0.3 54 <13 1600 0.2 <0.11 120 4700 <1.1

BG-1 10/19/2011 0.33 38 <13 1900 0.28 <0.11 150 5700 <1.1

BG-1 11/10/2011 0.35 67 <13 1400 0.26 <0.11 170 4400 <1.1

BG-1 12/1/2011 0.35 170 <13 1300 0.25 <0.11 120 3900 <1.1

BG-1 3/15/2012 0.24 0.27 <0.11 96 <1.1

BG-1 4/11/2012 0.31 0.2 <0.11 77 <1.1

BG-1 1/14/2013 0.088 <0.75 <0.55 120

IW-1 9/2/2010 0.17 57 <1.1

IW-1 12/3/2010 0.35 25 0.34 0.45 210 <1.1

IW-1 12/28/2010 0.43 67 <0.17 <0.11 33 <1.1

IW-1 1/26/2011 0.28 57 <0.17 <0.11 160 <1.1

IW-1 2/22/2011 0.23 45 0.19 <0.11 190 1.3

MW-1 2/12/2010 0.29 100 3.8 <1.1

MW-1 6/28/2010 82 <1.1

MW-1 7/30/2010 94 <1.1

MW-1 8/25/2010 0.21 98 <1.1

167


Dioxide

Carbon

Monoxide



MW-1 10/5/2010 0.32 83 1 0.29 640 <1.1

MW-1 10/28/2010 0.26 120 0.19 <0.11 45 1.3

MW-1 12/3/2010 0.33 96 <0.17 <0.11 28 <1.1

MW-1 12/29/2010 0.39 120 <0.17 <0.11 48 <1.1

MW-1 1/26/2011 0.27 100 0.18 <0.11 57 <1.1

MW-1 2/23/2011 0.24 95 0.56 <0.11 230 4.8

MW-1 5/19/2011 0.32 110 0.92 <0.11 260 1.2

MW-1 6/21/2011 0.33 91 1 <0.11 330 <1.1

MW-1 7/19/2011 0.38 110 2.5 <0.11 340 <1.1

MW-1 9/8/2011 0.42 120 <13 0.31 <0.11 63 4800 <1.1

MW-1 9/16/2011 0.34 120 <13 0.33 <0.11 110 6100 <1.1

MW-1 9/22/2011 0.32 120 <13 0.23 <0.11 81 5000 <1.1

MW-1 9/28/2011 0.35 100 <13 1700 0.23 <0.11 87 5200 <1.1

MW-1 10/19/2011 0.34 120 <13 1600 0.39 <0.11 110 4800 <1.1

MW-1 11/10/2011 0.34 330 <13 1500 0.35 <0.11 120 4700 <1.1

MW-1 12/1/2011 0.36 150 <13 1500 0.4 <0.11 140 4400 1.1

MW-1 3/14/2012 0.19 1.9 <0.11 6.8 1.6

MW-1 4/12/2012 0.083 1.9 <0.11 9 2.1

MW-1 1/15/2013 0.14 1.9 <0.55 130

MW-2 2/12/2010 0.28 74 11 <1.1

MW-2 6/28/2010 74 1.1

MW-2 7/30/2010 92 <1.1

MW-2 8/25/2010 0.24 62 <1.1

MW-2 10/5/2010 0.38 80 2.2 <0.55 1900 1.1

MW-2 10/28/2010 0.27 80 <0.17 <0.11 290 1.5

MW-2 12/2/2010 0.32 98 <0.17 <0.11 170 <1.1

MW-2 12/28/2010 0.36 110 <0.17 <0.11 180 <1.1

MW-2 1/26/2011 0.26 84 0.21 <0.11 190 <1.1

MW-2 2/22/2011 0.2 82 <0.17 <0.11 180 <1.1

MW-2 5/20/2011 0.38 93 1.3 <0.11 430 <1.1

168


Dioxide

Carbon

Monoxide



MW-2 6/21/2011 0.32 58 2.1 <0.11 800 1.3

MW-2 7/19/2011 0.41 84 2.4 <0.11 620 <1.1

MW-2 9/7/2011 0.45 90 <13 0.33 <0.11 160 5300 <1.1

MW-2 9/15/2011 0.33 110 <13 0.26 <0.11 140 4400 <1.1

MW-2 9/21/2011 0.32 110 <13 <0.17 <0.11 120 4800 <1.1

MW-2 9/28/2011 0.3 110 <13 1600 0.2 <0.11 110 4900 <1.1

MW-2 10/19/2011 0.31 91 <13 1500 0.29 <0.11 170 5000 <1.1

MW-2 11/10/2011 0.32 180 <13 1800 0.3 <0.11 180 5200 <1.1

MW-2 11/16/2011 0.26 220 <13 1500 0.2 <0.11 98 4200 <1.1

MW-2 12/1/2011 0.36 140 <13 1500 0.19 <0.11 69 4200 <1.1

MW-2 3/14/2012 0.09 2.6 <0.11 20 1.6

MW-2 4/11/2012 0.079 2 <0.11 30 <1.1

MW-2 1/14/2013 0.032 <0.75 <0.55 9.3

MW-3 9/2/2010 0.44 7 <1.1

MW-3 10/5/2010 0.37 56 <0.17 <0.11 13 <1.1

MW-3 10/28/2010 0.29 56 <0.17 <0.11 10 <1.1

MW-3 12/2/2010 0.33 70 <0.17 <0.11 11 <1.1

MW-3 12/28/2010 0.45 68 <0.17 <0.11 13 <1.1

MW-3 1/24/2011 0.28 45 0.26 <0.11 20 <1.1

MW-3 2/22/2011 0.16 57 <0.17 <0.11 26 1.6

MW-3 5/19/2011 0.36 29 <0.17 <0.11 82 1.3

MW-3 6/21/2011 0.43 9 <0.17 <0.11 190 <1.1

MW-3 7/19/2011 0.5 18 <0.17 <0.11 120 <1.1

MW-3 7/20/2011 0.45 30 <0.17 <0.11 67 <1.1

MW-3 7/21/2011 0.46 46 <0.17 <0.11 37 <1.1

MW-3 8/21/2011 0.39 59 <13 <0.17 <0.11 20 5300 <1.1

MW-3 8/23/2011 0.4 46 <13 <0.17 <0.11 23 5100 <1.1

MW-3 8/25/2011 0.37 51 <13 <0.17 <0.11 22 5200 <1.1

MW-3 8/27/2011 0.36 59 <13 <0.17 <0.11 24 6000 <1.1

MW-3 8/29/2011 0.35 76 <13 <0.17 <0.11 43 4800 <1.1

169


Dioxide

Carbon

Monoxide



MW-3 9/1/2011 0.45 56 <13 <0.17 <0.11 41 7100 <1.1

MW-3 9/8/2011 0.46 45 <13 0.17 <0.11 65 4000 <1.1

MW-3 9/15/2011 0.36 52 <13 <0.17 <0.11 64 5200 <1.1

MW-3 9/22/2011 0.39 47 <13 <0.17 <0.11 34 4900 <1.1

MW-3 9/28/2011 0.33 49 <13 1500 <0.17 <0.11 25 4300 <1.1

MW-3 10/5/2011 0.33 54 <13 1500 <0.17 <0.11 19 4400 <1.1

MW-3 10/12/2011 0.37 55 <13 1600 <0.17 <0.11 19 4800 <1.1

MW-3 10/19/2011 0.35 69 <13 1500 <0.17 <0.11 17 4400 <1.1

MW-3 10/26/2011 0.31 110 <13 1300 <0.17 <0.11 26 4000 <1.1

MW-3 11/2/2011 0.31 5400 <13 920 0.77 <0.11 23 3100 <1.1

MW-3 11/10/2011 0.16 17000 <13 150 1.9 <0.11 25 380 <1.1

MW-3 11/16/2011 0.067 19000 <13 190 1.3 <0.11 14 450 <1.1

MW-3 11/23/2011 0.065 9900 <13 100 0.33 <0.11 3.2 170 1.1

MW-3 11/30/2011 0.13 19000 <13 190 1.8 <0.11 14 360 <1.1

MW-3 3/15/2012 0.056 1.3 <0.11 3.7 <1.1

MW-3 4/12/2012 0.045 0.49 <0.11 2 1.6

MW-3 1/15/2013 0.16 <0.75 <0.55 8.2

MW-4 9/2/2010 0.35 80 <1.1

MW-4 10/5/2010 0.32 57 0.32 0.65 120 <1.1

MW-4 10/28/2010 0.28 80 <0.17 <0.11 17 <1.1

MW-4 12/3/2010 0.31 83 <0.17 <0.11 21 1.5

MW-4 12/29/2010 0.38 77 <0.17 <0.11 45 <1.1

MW-4 1/25/2011 0.26 68 <0.17 0.18 81 <1.1

MW-4 2/23/2011 0.21 65 1.1 <0.11 320 <1.1

MW-4 5/20/2011 0.35 84 1.8 <0.11 930 <1.1

MW-4 6/21/2011 0.3 73 <0.85 <0.55 1500 <1.1

MW-4 7/19/2011 0.39 74 1.8 <0.11 1000 1.7

MW-4 9/7/2011 0.41 99 <13 0.22 <0.11 130 4900 <1.1

MW-4 9/16/2011 0.33 110 <13 0.26 <0.11 200 5400 <1.1

MW-4 9/22/2011 0.36 110 <13 0.19 <0.11 150 4500 <1.1

170


Dioxide

Carbon

Monoxide



MW-4 9/28/2011 0.27 92 <13 1800 0.22 <0.11 180 5400 <1.1

MW-4 10/19/2011 0.33 96 <13 1700 0.19 <0.11 120 4900 <1.1

MW-4 11/10/2011 0.33 150 <13 1500 0.3 <0.11 200 4600 <1.1

MW-4 12/1/2011 0.35 140 <13 1500 0.26 <0.11 170 4600 <1.1

MW-4 3/14/2012 0.24 0.27 <0.11 110 1.1

MW-4 4/11/2012 0.32 0.28 <0.11 100 <1.1

MW-4 4/16/2012

MW-4 1/15/2013 0.13 1.3 <0.55 310

PW-1 2/12/2010 0.3 41 3.8 <1.1

PW-1 6/28/2010 17 <1.1

PW-1 7/30/2010 51 <1.1

PW-1 8/25/2010 0.15 30 <1.1

PW-1 12/4/2010 0.32 75 <0.17 <0.11 170 1.2

PW-1 12/27/2010 0.43 69 <0.17 <0.11 87 <1.1

PW-1 1/25/2011 0.29 63 0.37 0.12 260 <1.1

PW-1 2/24/2011 0.33 60 0.58 0.47 520 <1.1

impact of elevated dissolved co john david pugh rona …

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