DissertationMelanie McHenrySeptember 2010

Expected Graduation Date: December 2010Environmental Science Department, School of Science and Technology, College of Science Engineering

and Technology, Jackson State University, P.O. Box 18540, 1400 Lynch Street, Jackson, MS 39217

Ecotoxicity & Risk Assessment of Mercury in the Grand Bay National Estuarine Research Reserve:

Profiling Mercury Distribution in the NERR by Cold Vapor Atomic Absorption Spectrometery

The Element Mercury

• Mercury is present in the environment in Mercury is present in the environment in different forms that have biogeochemical different forms that have biogeochemical transformation and ecotoxicity.transformation and ecotoxicity.

• Mercury is one of the most hazardous pollutants Mercury is one of the most hazardous pollutants in the marine environment.in the marine environment.

• All forms of mercury can have adverse health All forms of mercury can have adverse health effects at sufficiently high doses.effects at sufficiently high doses.

• Organic mercury compounds are of particular Organic mercury compounds are of particular concern because of their enhanced toxicity, concern because of their enhanced toxicity, lipophilicity, and bioaccumulation in tissues.lipophilicity, and bioaccumulation in tissues.

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Organic MercuryMost toxic because they are lipophilic & can penetrate

the blood brain barrier (BBB), invade the nervous system

Inorganic MercuryIngestion is usually inadvertent or with suicidal

intent & gastrointestinal ulceration or perforation & hemorrhage have been rapidly produced it

will followed by circulatory collapse

Elemental MercuryVolatile at room temperature

After inhalation, pass through pulmonary, enter blood and distribute to red blood cells,

central nervous system (CNS), & kidneys

33

Mercury Cycle• Aquatic systems are a reservoir of mercury

containing annual flux to & from the atmosphere

• Estuaries & coastal waters represent a link between the terrestrial environment & the open waters

• Small fraction of the mercury transported in rivers is exported to open waters due to the high retention of this metal in estuaries & coastal waters

• Mercury emissions disperse widely in the atmosphere before being deposited to the earth’s surface

• The lifetime of mercury in sediments is so long that they can be considered as sinks for this metal

• Microorganisms in sediments can convert several mercury compounds into a more toxic & water-soluble form

44

Grand Bay National Estuarine Research Reserve (GBNERR)

• The Grand Bay Reserve is about 18,500 acres & the Grand Bay National Wildlife Refuge is 7,000 acres– A vast area of undeveloped coastline &

marshes – Consists of a maze of bayous, small bays,

marsh islands & mudflats

• Anthropogenic-induced stressors– The population has increased in areas

close which has resulted in• Substantial land development• Dredging, Spoil placement• Dumping of wastesImpact• Considerable habitat loss• Increased chemical pollution• Intensified hypoxic events

55

Mercury in Surface Water

• In 1970, sampling from U.S. lakes & rivers demonstrated that about 19% of the waterways are contaminated with mercury with a median value less than 0.5 ppb

• Main sources of MeHg in water Direct precipitationWatershed runoff (especially from

wetlands)In-lake methylation of inorganic Hg

66

Mercury in Sediment• Main reservoirs are the bottom sediments

– Sensitive indicator of the aquatic ecosystems pollution

– Toxicity, bioaccumulation, & mobility depends on the species and chemical form

• Concentration/Bioaccumulation– Accumulates in bottom sediment via

sedimentation – An indicator of water pollution with this

element

• Methylation/Microbes– Inorganic Hg is transformed into

methylmercury– Main factors are microorganisms, inorganic

sulfides, iron & manganese hydroxides, redox potential, chlorides & temperature in bottom sediments

77

Mercury in Fish Muscle Tissue• Nearly all mercury is methylmercury >95%

• Exposure occurs almost completely through the consumption of seafood

• Hg vs fish species– Large, long-lived fish to have increased levels of

mercury– Bioaccumulates in successive order in the food chain – Hg levels increase with age

88

Common GBNERR Fish

Grand Bay NERR Fish Species

Yellowfin mojarra

Gerres cinereus

Pinfish Lagodon rhomboids

Sheepshead minnow

Cyprinodon variegates

Bull minnow Fundulus grandis

Gulf pipefish Syngnathus scovelli

Flounder Paralichthys lethostigma

Sailfin molly Poecilia latipinna

Gulf Kilifish Fundulus grandis

Mercury in Atmosphere & Deposition• Atmospheric Hg is the main source of Hg in the ocean

• Easily transported over long distances– The global sea-air flux of mercury is estimated between 4-13

Mmol/year – Regional & temporal variability depends on local wind

speed, temperature, aqueous mercury concentration, & biological activity

• Forms– Elemental Hg0 is dominant form of atmospheric Hg (95%)– Atmospheric pool also include Hg in particulate form

99

Mercury vs Human Health

1010

Acute Exposure

Brain functioning– Irritability– Shyness– Tremors– Changes in hearing– Memory problems

Exposure to high levels– Mental retardation– Cerebral palsy– Seizures– Ultimately death

Chronic Exposure

Central Nervous Systempermanent damage

Continued Hg exposure– Progressive tremor – Erethism– Emotional lability– Memory

impairment– Salvation,

excessive sweating, Potential factor of autism

Reference Dose (RfD)

• Health authorities & resource managers are concerned with the risk associated with mercury exposure

• The reference dose (RfD) that presents no risk to the public in general

• United States Environmental Protection Agency (U.S. EPA)– Ingestion of Methylmercury– 0.1 ppb (µg/kg)

1111

Rationale

• No previous research about monitoring the concentrations of Hg at the Grand Bay National Estuarine Research Reserve (GBNERR)

• Need data to develop strong polices for managing mercury contamination

• Assesses spatial & temporal distribution of Hg in fish, water, & sediment from NERR

• Assesses potential health risks associated with fish consumption

1313

Goals & ObjectivesThe goal of the proposed research is to assess the spatial & temporal distribution of mercury in selected environmental samples including fish, water, sediment, & atmospheric (particulate) samples collected from the Grand Bay NERR

1414

Specific objectives of this project are:

1. To develop and optimize cold vapor AAS method for mercury speciation using Leeman Labs HYDRA AA system

2. To determine total (T-Hg), inorganic (I-Hg) & methylmercury (MeHg) concentration in water, sediment, & fish samples,

3. To assess seasonal variability, relationship among surface water, sediment, fish species, sampling sites,

4. To identify if chlorophyll, an environmental factor,

controlling mercury availability

5. To monitor and model the seasonal trend in atmospheric concentrations of mercury at the Grand Bay NERR

Hypothesis

• Mercury levels will be higher in warmer months in surface water, sediment, and fish tissue

• Surface water and sediment will have a direct correlation, with sediment having the highest mercury levels

• Availability of Hg will be higher in spring and summer

• The ambient mercury levels will not exceed the Environmental Protection Agency’s Reference Dosage (RfD)

1515

Research Approach & Methods

• Optimize the Hydra AA

– Inorganic Mercury

– Total Mercury

• Select & georeference (GPS) sample collection sites

• Perform in-situ analysis of temperature, DO, pH, Conductivity, Salinity, TDS, Turbidity

• Collect water and sediment samples

• Collect fish samples

– Identify species

– Record length & size

• Analyze samples by CV-AAS using HYDRA AA

• Data analysis to determine relationships between Hg concentrations & fish species

• Perform health risk assessment based on recommended EPA assumptions

1717

Materials & Methods: The Collection

Grand Bay NERRSampling Sites

Sample Site Latitude Longitude

GB 22 30.369037 -88.466219

GB 23 30.356549 -88.467377GB 24

Fish Site 130.350465 -88.463557

GB 25 30.352468 -88.427689

GB 26 30.397086 -88.445923

GB 7 30.382192 -88.438446

GB 8 30.372279 -88.443850

GB 9 30.361141 -88.439030GB 15

Fish Site 330.38455 -88.43997

GB 16 30.407844 -88.400741

GB 17 30.396774 -88.401534Fish Site 4 30.37228 -88.44385049

GB 18 30.385505 -88.397298Fish Site 2 30.38467 -88.40028333

GB 12 30.380090 -88.402482

• Specific JSU Sampling Sites

• Simple Random Sampling– Each population unit has an equal

change of being selected for measurement

• Chosen in 2003 by Woodrey & Farah

Collection TechniquesWater• Collected into 250-mL plastic bottles• Filtered in lab • YSI Meter: Multi-parameter probe

– Measure depth, pH, DO, turbidity, & conduct.– Readings taken from 1 m below surface

Fish• Sampling Seine Net, 1 inch opening, 16 feet long• Stored in polypropylene bag (Ziplock bag)• Stored on ice

Sediment• Via Sediment Grabber into plastic bag (Ziplock bag)• Stored on ice

Atmospheric Samples• National Atmospheric Deposition Program (NADP)

2008

2020

Materials & Methods: Sample Analysis

Digestion: Digi Prep MS(from SCP Science)

• Teflon digestion tubes• Digestion of Sediment Samples

0.5-1 g of soil in 4 mL of HCl

Digested 4 h at 160oC

Dilute to 50 mL in water

• Water Samples

– Filtered with 0.45 µm filters into 50 mL tubes and acidified to 5% HCl

• Digestion of Fish Samples

– 0.5-1g of tissue digested in 4 mL HCl

– Digested 3-4 h at 160oC

– Dilute to 50 mL

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Cold Vapor Atomic Absorption (CVAAS) for Hg

• HYDRAA AA manifiold for Hg speciation

• Compliant with EPA protocols for Hg speciation

N2

Hg(0)

AAS cell

Waste

Sample

Oxidant

Reductant

Hg lamp

• Sample flow - 3 mL/min

• Oxidant flow – 1.5 mL/min

• Reductant flow – 1.5 mL/min

• N2 set at 0.35 liter/min

– Rinse at 35 seconds

– Uptake at 40 seconds

Total and Inorganic Hg detectionTotal Mercury Determination

Inorganic Hg: Sample mixed water and reacted with 1% SnCl2

Total Hg: Sample mixed 0.1% KMnO4 (oxidant) and reacted with 0.5% NaBH4

Inorganic Hg Determination

Sample

H2O

SnCl2

Sample

KMnO4

NaBH4

Additional Parameter Analysis

Conducted with the YSI-meter at site or analyzed with the 10-AU Fluorometer

YSI-Meter

• Temperature• Dissolved Oxygen (DO)• pH• Salinity• Total Dissolved Solids (TDS)• Turbidity

10-AU Fluorometer

• Chlorophyll

2525

Materials & Methods: Data Analysis

Data AnalysisStatistical Analysis System: SAS

• SAS: a powerful tool for analysis of data

• Contains an extensive library of statistical procedure or PROCs– PROC CORR - descriptive

statistics– PROC FREQ - counts of

number cases – PROC MEANS - descriptive

statistics (sample size, mean, variance, standard deviation, range, and minimum and maximum)

– PROC ANOVA - analysis of variance for balanced data from a wide variety of experimental designs

ArcView

• It is an analytical tool• Attribute Data into Arc/INFO

– Create a new INFO data file to hold the attributes

– Add the attribute values to the newly created INFO data file

– Relate or join the attributes in the INFO data to the feature attribute table in order to manage the database

• Geographic features using real-world coordinates are recorded

• Related coverage in one common coordinate system must be stored

2727

ResultsResults

CVAAS: Optimization of Acidity

• Absorbance from Hg via Hydrochloric and Nitric acids

• For percentages over 4% of acid, HCl had a greater count rate

• These results indicate that at 10% level, all acids were more effective.

• Data represented in figure indicates a strong concentration-dependent response

• Hydrochloric acid had a greater overall effect than nitric acid

CVAAS: Effect of HCl

10 ppb In-Hg or MeHg in different HCl solutions mixed with water and KMnO4

followed by reduction by SnCl2 or NaBH4, respectively.

1% HCl acidity is sufficient for both MeHg and In-Hg with suitable reductants

MeHg does not react without NaBH4. Oxidation to inorganic Hg with KMnO4 is essential before reduction to elemental Hg0.

0

100000

200000

300000

400000

0 1 2 3 4 5 6

HCl conc (%)

Sig

na

l

10ppb MeHg-0.5% KMnO4-0.5% NaBH4

10ppb-H2O-0.5% NaBH4

10ppb MeHg-0.5% KMnO4-2% SnCl2

10ppb In-Hg-H2O-2% SnCl2

10ppb InHg-H2O-0.5% NaBH4

CVAAS: Effect of NaBH4

10 ppb In-Hg or MeHg in 2% HCl treated either with NaBH4 and DI or NaBH4 and KMnO4

0.4-0.6% NaBH4 appears to be sufficient for complete reduction of MeHg.

0

100000

200000

300000

0 0.2 0.4 0.6 0.8 1 1.2

NaBH4 (%)

Sig

na

l 10 ppb Hg-H2O-NaBH4

10 ppb MeHg-0.2% KMnO4 -NaBH4

10 ppb MeHg-H2O-NaBH4

CVAAS: Effect of SnCl2

10 ppb In or MeHg in 2% HCl treated either with SnCl2 and DI or SnCl2 and KMnO4

SnCl2 does not affect MeHg even in the presence of KMnO4.

0

100000

200000

300000

400000

0 1 2 3 4 5 6

SnCl2 (%) in 2% HCl

Sig

nal 10 ppb Hg-H2O-SnCl2

10 ppb MeHg-H2O-SnCl2

10 ppb MeHg-0.2% KMnO4-SnCl2

10 ppb In-Hg-0.2% KMnO4-SnCl2

CVAAS: Optimization of N2 Flow rate

• Obtain highest signals by controlling the residence time of Hg0 in light path

• Flow rates below 0.3 LPM, there was an increase in the response via count rate

• These results indicate that optimum signal could be obtained around 0.3 LPM without experiencing memory effects

• Flow rates below 0.30 LPM were not suitable for cleaning the system. Memory effects dominate.

Mercury in Surface Water

• October had the highest amount of all mercury species

•

• Statistical analysis for monthly variation

• Total Hg: No significant differences (P = 0.2042)

• In-Hg: No significant differences (P = 0.3881)

• MeHg: No significant differences (P = 0.6531):

• Sampling: July 2009 to April 2010

• In-Hg was ascertained from SnCl2, total Hg levels were ascertained from NaBH4 and KMnO4. Organic mercury levels were determined by subtracting In-Hg from total Hg levels

Mercury in Sediment Samples

• Hg in sediments was mostly inorganic

Statistical analysis for Monthly variation

• Tot-Hg: No significant variation (P = 0.2042)

• In-Hg: Significant variation

(P = 0.0212)

• MeHg: Significant variaition

(P = 0.0128)

•Sampling months: July 2009 to April 2010

•In-Hg was ascertained from SnCl2, total Hg were ascertained from NaBH4 and KMnO4. •Organic Hg levels were determined by subtracting inorganic levels from total mercury levels.

Seasonal Variability of Hg in Surface Water

Tot Hg: Variations are not significant (P=0.4969)

In-Hg: Variations are not significant (P=0.2718)

MeHg: Variations are not significant (P=0.1695)

Seasons: Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)

Seasonal Variability of Hg in Sediment

Tot-Hg: Variations are significant (P = 0.0208)

In-Hg: Variations are significant (P = 0.0212)

MeHg: Variations are significant (P = 0.0128)

Seasons: Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)

Seasonal Variability of Hg in Fish

Tot. Hg: no significant difference (P = 0.2489)

In-Hg: no significant difference (P = 0.2516)

MgMe: no significant difference (P = 0.3517)

Seasons: Spring (March and April), Summer (July and August), Fall (September, October, and November), and Winter(: December, January, and February)

Chlorophyll vs Hg Availability

Strong chlorophyll-dependent response in Febr. and a smaller peak in Sept.

Site-by-Site: No significant difference (P = 0.1925)

Tot-Hg: No significant differences water, sediment, and fish tissue (P = 0.5905)

Hg Levels in Tissues of Fish collected from NERRMonthly variation

• Strong inorganic mercury-dependent response in total mercury

• Most Hg is organic mercury

• Total (P = 0.646), & Organic (P = 0.1592) Hg levels did not vary significantly

• Inorganic Hg varied significant (P= 0.0181)

Hg Levels in Tissues of Fish collected from NERR Variation across Sites

• Tot-Hg: not a significant difference (P=0.646)

• In-Hg: significant differences among sites (P=0.0181)

• MeHg: not a significant difference (P=0.1592)

Relationship among Surface Water, Sediment, & Fish Tissue

Total Hg = No significant difference on a site-by-site basis (P= 0.5905) among surface water, sediment, & fish tissue

No significant difference in surface Water (P = 0.3012), Sediment (P = 0.3053), and Fish Tissue (P = 0.3700)

Mercury Concentrations in Fish Species

Different species were expected to have differences in Hg levels

No significant differences in Total Hg (P=0.5647), In-Hg (P=0.2685), & MeHg (P=0.3921)

Most Hg was organic form

Site-by-site variation are not significant for: Yellowfin (P= 0.5419), Pinfish (P= 0.9166), Sheepshead (P= 0.0710), Bull minnow (P= 0.3093), Flounder (P= 0.6747), and Sailfin molly (P= 0.8619)

Not Significant for: Gulf pipefish (P = <0.0001) and Gulf kilifish (P = 0.0010)

Mercury Concentrations in Fish Sampling Sites

• Total Hg: No significant difference on a site-by-site basis (P=0.0575)

• In-Hg: No significant difference on a site-by-site basis (P=0.2047)

• MeHg: Significant difference on a site-by-site basis (P = 0.0227) • Strong inorganic Hg-dependent response

in total mercury

• Most Hg in fish tissue samples was organic mercury

Monthly Mercury Levels associated with Fish Consumption

• Fish tissue samples collected monthly from the NERR was expected to have significant difference from the EPA’s reference dosage (RfD)

– 0.1 ppb for MeHg

– Ingestion

• There was a strong inorganic mercury-dependent response in total mercury.

• Most mercury in fish tissue samples was organic mercury

• Significant difference among species for Total Hg (P < 0.0001)

Seasonal Trend in Atmospheric Levels of Hg at the Grand Bay NERR

Monitor

• Monthly Hg levels are not significantly different (P=0.8041)

• Seasonal Hg levels are not significantly different (P=0.7061)

Model

• National Atmospheric Deposition Program (NADP), newest data: 2008

• Mapped using ArcView after obtaining a raster image from Maris of the Grand Bay National Estuarine Research Reserve

• ArcView used to illustrate the special and temporal changes in atm Hg between seasons

Mercury Concentrations in Filtered Surface Water

• Results indicate that October had the highest amount of all mercury species

• Surface Water: Total, Inorganic, & Organic Hg were not significantly different

Month Total (ppb) Inorganic (ppb) Organic (ppb)

July 0.09 ± 0.002 0.001 ± 0.001 0.008 ± 0.003Aug 0.01 ± 0.002 0.002 ± 0.001 0.008 ± 0.001Sept 0.01 ± 0.001 0.005 ± 0.001 0.006 ± 0.001Oct 0.026 ± 0.007 0.005 ± 0.004 0.021 ± 0.004Nov 0.01 ± 0.001 0.002 ± 0.001 0.009 ± 0.001Dec 0.012 ± 0.002 0.003 ± 0.001 0.008 ± 0.002Jan 0.006 0.005 0.001 ± 0.001Feb 0.009 ± 0.001 0.001 0.008 ± 0.001Mar 0.011 ± 0.001 0.000 0.011 ± 0.001Apr 0.072 ± 0.246 0.000 0.072 ± 0.246

Mercury Concentrations in Sediment Samples

• Results indicate that October was the month that had the highest amount of all mercury species

• Sediment: Total mercury was not significantly different, however, Inorganic and Organic mercury were not significantly different

Month Total (ppb) Inorganic (ppb) Organic (ppb)

July 0.001 ± 0.001 0.001 ± 0.001 0.001 ± 0.001Aug 0.001 0.001 0.000

Sept 0.000 0.000 0.000

Oct 0.001 ± 0.001 0.000 0.000

Nov 0.001 ± 0.001 0.001 0.000

Dec 0.001 ± 0.001 0.001 0.000

Jan 0.001 ± 0.002 0.001 ± 0.002 0.000

Feb 0.001 ± 0.002 0.000 0.000Mar 0.001 0.001 0.000Apr 0.002 ± 0.001 0.001 ± 0.002 0.000

Seasonal Variability of Surface Water, Sediment, and Fish Samples

• Environmental matrices collected seasonally were expected to have significant difference• Surface Water:

– Total, Inorganic, & Organic mercury: no significant difference – On a seasonal basis, there was no significant difference in mercury species concentration

• Sediment– Total, Inorganic, & Organic mercury: significant difference– On a seasonal basis, there was a significant difference in mercury species concentration

• Fish Tissue– Total, Inorganic, &Organic mercury: no significant difference– On a seasonal basis, there was no significant difference in mercury species concentration

Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb)

Water Sediment Fish Water Sediment Fish Water Sediment Fish

Summer 0.019±0.004 0.002±0.001 6.11±1.334 0.003±0.002 0.001±0.001 2.42±0.252 0.016±0.004 0.001±0.001 3.69±1.15

Fall 0.015±0.003 0.001±0.001 2.37±0.804 0.004±0.002 0.000 1.15±0.445 0.012±0.002 0.000 1.36±0.73

Winter 0.009±0.001 0.001±0.001 2.45±0.609 0.003 0.001±0.001 1.23±0.387 0.006±0.001 0.000 1.52±0.61

Spring 0.009±0.002 0.001±0.001 1.13±0.632 0.000 0.001±0.001 0.676±0.406 0.009±0.002 0.000 0.456±0.249

Chlorophyll versus Mercury Availability

Strong chlorophyll-dependent response in February & a smaller peak in Sept.

No significant differences on a site-by-site basis for surface water, sediment, and fish tissue samples

Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb)

MonthChlorop

hyll (ppb)

Surface Water

Sediment Fish Surface Water

SedimentFish

Surface Water

Sediment Fish

July 0.731±0.463 0.09±0.002 0.001±0.001 0.696±0.285 0.001±0.001 0.001±0.001 0.173±0.03 0.008±0.003 0.001±0.001 0.524±0.264

Aug 0.813±0.524 0.01±0.002 0.001 5.42±1.052 0.002±0.001 0.001 2.25±0.222 0.008±0.001 0.000 3.16±0.895

Sept 1.14±0.632 0.01±0.001 0.000 2.31±0.871 0.005±0.001 0.000 1.38±0.758 0.006±0.001 0.000 0.928±0.523

Oct 0.736±0.505 0.026±0.007 0.001±0.001 2.71±1.03 0.005±0.004 0.000 1.13±0.123 0.021±0.004 0.000 1.57±0.997

Nov 0.583±0.473 0.01±0.001 0.001±0.001 2.104±0.513 0.002±0.001 0.001 0.956±0.455 0.009±0.001 0.000 1.59±0.671

Dec 0.287±0.234 0.012±0.002 0.001±0.001 2.31±0.696 0.003±0.001 0.001 1.41±0.293 0.008±0.002 0.000 0.904±0.481

Jan 1.44±0.662 0.006 0.001±0.002 2.06±0.426 0.005 0.001±0.002 1.15±0.434 0.001±0.001 0.000 1.83±0.678

Feb 1.98±0.818 0.009±0.001 0.001±0.002 2.991±0.704 0.001 0.000 1.15±0.434 0.008±0.001 0.000 1.83±0.678

Mar 1.43±0.595 0.011±0.001 0.001 0.897±0.896 0.000 0.001 0.471±0.497 0.011±0.001 0.000 0.425±0.403

Apr 0.889±0.363 0.072±0.246 0.002±0.001 1.36±0.368 0.000 0.001±0.002 0.88±0.315 0.072±0.246 0.000 0.488±0.095

Relationship between Surface Water, Sediment, & Fish Tissue

No significant differences for surface water, sediment, and fish tissue samples on a monthly basis

No significant differences for surface water, sediment, and fish samples on a site-by-site basis

Total Hg (ppb) Inorganic Hg (ppb) Organic Hg (ppb)

MonthSurface Water

SedimentFish

TissueSurface Water

Sediment Fish Tissue

Surface Water

SedimentFish

Tissue

July 0.09±0.002 0.001±0.001 0.696±0.285 0.001±0.001 0.001±0.001 0.173±0.03 0.008±0.003 0.001±0.001 0.524±0.264

Aug 0.01±0.002 0.001 5.42±1.052 0.002±0.001 0.001 2.25±0.222 0.008±0.001 0.000 3.16±0.895

Sept 0.01±0.001 0.000 2.31±0.871 0.005±0.001 0.000 1.38±0.758 0.006±0.001 0.000 0.928±0.523

Oct 0.026±0.007 0.001±0.001 2.71±1.03 0.005±0.004 0.000 1.13±0.123 0.021±0.004 0.000 1.59±0.997

Nov 0.01±0.001 0.001±0.001 2.10±0.513 0.002±0.001 0.001 0.956±0.455 0.009±0.001 0.000 1.59±0.671

Dec 0.012±0.002 0.001±0.001 2.31±0.696 0.003±0.001 0.001 1.41±0.293 0.008±0.002 0.000 0.904±0.481

Jan 0.006 0.001±0.002 2.06±0.426 0.005 0.001±0.002 1.15±0.434 0.001±0.001 0.000 1.83±0.678

Feb 0.009±0.001 0.001±0.002 2.99±0.704 0.001 0.000 1.15±0.434 0.008±0.001 0.000 1.83±0.678

Mar 0.011±0.001 0.001 0.897±0.896 0.000 0.001 0.471±0.497 0.011±0.001 0.000 0.425±0.403

Apr 0.072±0.246 0.002±0.001 1.36±0.368 0.000 0.001±0.002 0.88±0.315 0.072±0.246 0.000 0.488±0.095

Mercury Concentrations in Fish Species

• No significant difference in Yellowfin, Pinfish, Sheephead minnow, Bull minnow, Flounder, and Sailfin Molly, but significant difference Gulf pipefish and Gulf kilifish

• No significant differences for Total, Inorganic, and Organic mercury on species basis

Species Total (ppb) Inorganic (ppb) Organic (ppb)

Yellowfin mojarra 0.409 ± 0.036 0.132 ± 0.017 0.277±0.053

Pinfish 2.46 ± 2.06 0.756 ± 0.415 1.713±1.886

Sheepshead Minnow 1.64 ± 1.02 0.641 ± 0.523 1.006±4.959

Bull Minnow 1.73 ± 1.63 0.651 ± 0.611 1.085±4.065

Gulf Pipefish 0.373 ± 1.75 0.100 ± 0.822 0.273±1.878

Flounder 1.54 ± 1.105 0.103 ± 0.12 1.438±1.309

Sailfin Molly 1.57 ± 0.63 0.467 ± 0.222 1.106±0.451

Gulf Kilifish 3.39 ± 1.67 0.915 ± 0.816 2.475±2.016

Mercury Concentrations in Fish Sampling Sites

• 4 sites selected based on:

– Accessibility of the boat

– Depth of the areas

Total Hg- No significant difference on a site-by-site basis

In-Hg- No significant difference on a site-by-site basis

MeHg- significant difference on a site-by-site basis

Site Average

Total (ppb)

Inorganic (ppb)

Organic (ppb)

FS1 2.30 ± 1.39 1.04 ± 0.830 1.42 ± 1.00

FS2 1.88 ± 1.30 0.9 ± 0.613 1.05 ± 0.836

FS3 2.79 ± 1.38 1.27 ± 0.538 1.60 ± 0.985

FS4 2.17 ± 1.67 1.17 ± 0.610 1.23 ± 1.15

Potential Health Risk associated with Fish Consumption

• Reference Dosage (RfD)

– Based on neurologic developmental effects

– Measured in children associated with exposure in utero to MeHg from maternal diet

• For organic mercury, there is a significant difference on a monthly basis

Month Organic (ppb) EPA's RfD

July 0.524 ± 0.264 0.1

August 3.168 ± 0.895 0.1

September 0.928 ± 0.523 0.1

October 1.579 ± 0.997 0.1

November 1.594 ± 0.671 0.1

December 0.904 ± 0.481 0.1

January 1.839 ± 0.678 0.1

Febuary 1.839 ± 0.678 0.1

March 0.425 ± 0.403 0.1

April 0.488 ± 0.095 0.1

Seasonal Trend in Atmospheric Concentrations of Hg at NERR

• Atmospheric analysis were expected to have significant difference on

• monthly and seasonal basis

• Total mercury was highest in Summer• Hg content of atmospheric samples,

the p-value was 0.7061 which means that there was not a significant difference on a monthly basis for total mercury

Month Total Hg (ppb)

Jul 12.5 ± 6.02

Aug 19.1 ± 6.47

Sept 12.0 ± 2.92

Oct 9.14 ± 1.26

Nov 8.35 ± 8.46

Dec 6.92 ± 2.09

Jan 8.67 ± 4.03

Feb 8.36 ± 10.5

Mar 5.44 ± 9.46

Apr 8.67± 5.59

Conclusions

• Monthly carrying loads of inorganic and organic Hg varied significantly for surface water and sediment

• These values were not stable, unlike total mercury

• Hg loads did not flux seasonally or on a site-by-site basis for surface water, sediment, or fish tissue

• Chlorophyll did not change at a rate significantly different from Hg levels in surface water and sediment, suggesting there is a possible link

• Fish tissue - monthly carrying loads of organic Hg vary significantly, unlike total and inorganic mercury

• Species effect - No significant differences on a species basis for fish tissue

• Monthly Hg levels in fish were found to be statistically different from EPA’s RfD

• Atmospheric Hg levels only differed on a monthly basis for organic Hg

• No significant monthly differences in the carrying load of total or inorganic Hg

• Atmospheric levels of Hg did not differ on a seasonal basis.

Special ThanksZikri ArslanProfessor of Environmental ChemistryPaul Tchounwou , Sc.D., F.A.B.I., I.O.M.Professor, Chair & Director Environmental Science Ph.D. ProgramYerramilli AnjaneyuluProfessor of Chemistry, Director, GIS Remote Sensing Latoya MylesPhysical Scientist with the Air Resources Laboratory’s Atmospheric Turbulence & Diffusion Division (ATDD)Hyun Jung ChoAssociate Sensing & GISStephen KishiniNOAA PhD StudentChristina WattersECSC CoordinatorPaulette BridgesHilliard LackeyDr. Mark HardyDr. Greg Begonia

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Acknowledgements

This research was supported, in part, by a grant from the National Oceanic & Atmospheric Administration grant # NA17AE1626, Subcontract # 27-0629-017, through the Environmental Cooperative Science Center at Florida A&M University to Jackson State University and the support of the Atmospheric Deposition Program of the Trent Lott Geospatial and Visualization Research Center

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Any Questions

Total Release Inventory (TRI)

On-Site Disposal to Class I Underground Injection Wells, RCRA Subtitle C Landfills,

and Other Landfills

Other On-site Disposal or Other Releases

ChemicalOther Onsite

LandfillsSubtotal

Point Source Air Emissions

Surface Water Discharges

Subtotal

Total Onsite Disposal or

Other Releases

Total Onsite and Offsite Disposal or

Other Releases

Mercury (lb)

Mercury Compounds (lb)

9 9 240 3 243 251 251

CHEVRON PRODUCTS CO PASCAGOULA REFINERY. 250 INDUSTRIAL RD, PASCAGOULA, Mississippi 39581 (JACKSON)

Mercury Compounds (lb)

0 0 16 3 18 18 18

MISSISSIPPI POWER CO - PLANT DANIEL. 13001 HWY 63 N, ESCATAWPA, Mississippi 39552 (JACKSON)

Mercury Compounds (lb)

9 9 225 0 225 253 253

MIDSTREAM FUEL SVC LLC (PASCAGOULA). 5320 INGALLS AVE, PASCAGOULA, Mississippi 39581 (JACKSON)

Mercury Compounds (lb)

0 0 0 0 0 0 0