A Research Study presented to the faculty of Chemical Engineering Department

In Partial Fulfillment of the requirements for the Degree of

Bachelor of Science in Chemical Engineering

Submitted by:

Empeynado, Rudolf Gray A.

Jardinico, Nikki P.

Malasabas, Mariecor I.

Naperi, Jasmine Joyce T.

Raypan, Mike Lester T.

Engr. Merlinda Palencia

Engr. Sherrie Mae Medez

Research Advisers

26 March 2010

APPROVAL SHEET

This proposed research entitled:

“Quantitative Assessment of Cu, Pb, Hg, Zn and PCB Concentrations and 210Pb

Radiometric Dating of Sediments in Estero de Balete”

Prepared and submitted by:

Empeynado, Rudolf Gray A. Malasabas, Mariecor I. Raypan, Mike Lester T.

Jardinico, Nikki P. Naperi, Jasmine Joyce T.

Has been successfully defended last March 12, 2010 and is hereby approved to continue

the research.

Engr. Sherrie Mae Medez Engr. Albert Evangelista

Adviser Adviser

Engr. Atlas Cerbo Engr. Jerry Olay

Panelist Panelist

Engr. Merlinda Palencia

Chairperson

CHAPTER 1

INTRODUCTION

1.1 Background of the Study

There is an increasing concern about heavy metal contamination in river systems.

Rivers play major roles to the community especially in the fishing industry and a

source of water supply for people residing within the vicinity of the area. River

contamination either directly or indirectly will affect humans as final consumers.

Although some of heavy metals are required as micronutrients, it can be toxic when

present higher than the minimum requirements.

Here in the Philippines, the Pasig River is one of the major rivers and, together

with Manila Bay and Laguna de Bay, forms the most important natural water system

in Metro Manila. The river passes through the urban areas of the metropolis from its

upstream portion west of Laguna de Bay, moving downstream to east of Manila Bay.

The influx of population brought about by industrialization and urbanization of

Metro Manila resulted in the transformation of Pasig River into a sewage and

industrial effluents depot.   The river is known to have high organic loads and

contaminate with heavy metals, pesticides, nitrates, and phosphates.  The presence of

these materials has degraded the water quality of Pasig River consequently upsetting

its ecological balance. It has become much polluted and is considered dead or not

able to sustain life by most ecologists.

Pasig River tributaries contribute to the current state of the river. One of those

tributaries is the Estero de Balete which runs from Romualdez Street to Taft Avenue.

Consequently, wastes from the tributary are transferred to the Pasig River, thus,

contributing to its pollution load.

Currently, the Philippine government is conducting series of rehabilitation

programs and strategies to restore the pristine condition of the river. The Pasig River

Rehabilitation Commission (PRRC) was established in year 1999 to oversee

rehabilitation efforts for the river. Supporting the PRRC are private sector

organizations like the Clean and Green Foundation, Inc. which implemented the “Piso

Para sa Pasig” campaign. One of the programs established was the provision of

environmental aides that take charge of collecting garbage and solid wastes along the

112-kilometer stretch of navigable estuaries of the river, including creeks and

tributaries. Researches about Pasig River have been supported and funded to bring

about long-term solutions for this frustrating predicament on the river. Environmental

regulations are also enforced to impede violators from dumping garbage in estuaries

and creeks and reduce pollution loading from domestic and commercial or industrial

wastewater sources.

This study is concerned with the sediment analysis of Estero de Balete.

Assessment of the heavy metal content of the sediments in Estero de Balete can

provide an overview of the degree at which the tributary is contaminated. Using this

as a basis, methods on how to control or limit production of wastes can be made.

Pollution sources can be determined and remediation can be done to reduce the

pollution of the tributary that contributes to Pasig River.

1.2 Statement of the Problem

This study aims to quantify and assess the extent of copper, lead, mercury, zinc

and polychlorinated biphenyl contamination in the sediments in Estero de Balete.

Specifically, the study will:

1. Measure the concentration of copper, lead, mercury, zinc and polychlorinated

biphenyl (PCB) in the sediments of Estero de Balete in mg/kg dry weight of

sediments.

2. Determine the age of deposition of sediments in Estero de Balete through 210Pb dating.

3. Determine the relationship between the concentrations of the analytes and the

length of Estero de Balete in different specific time frames.

4. Evaluate the extent of heavy metal contamination of sediments in terms of

the following guidelines:

4.1 Ontario Sediment Quality Guidelines

4.2 National Oceanographic and Atmospheric Administration Sediment

Quality Guidelines

4.3 Australian and New Zealand Environment and Conservation Council

(ANZECC) Guidelines

4.4 Hong Kong Sediment Quality Guideline

1.3 Significance of the Study

Sediments are widely used environmental indicators. They show a high capacity

to accumulate and integrate over time contaminants in water. As such, they have the

ability to trace contamination sources and monitor contaminants. In addition to water

quality monitoring of aquatic systems, evaluation of sediments would provide

extensive assessment of contamination.

This study aims to be of aid for future remediation programs of Estero de Balete

as well as Pasig River. Concentrations of contaminants on Estero de Balete, being one

of the tributaries of Pasig River, could mirror the present state of the river. Moreover,

this study can be used as reference of future researches that are also concerned with

similar investigations.

1.4 Scope and Delimitation

This study concentrates on the analysis of the sediments of a portion of Estero de

Balete, particularly situated from Romualdez Street to Taft Avenue. Samples are

collected from identified parts of this range. The study tests only for the presence of

four pre-chosen heavy metals in the sediments due to their impact to the pollution of

bodies of water as well as their toxicity especially at elevated levels. These metals are

copper, lead, mercury and zinc. Polychlorinated biphenyls (PCBs) are also tested.

There is no attempt in remediating the sediments in this research.

This study also includes dating of the sediments at about 1 meter deep through

Core Sampling method. Three portions from different heights of the sediment sample

are to be taken to represent three different time frames. Sampling is only done once at

10 sampling sites. The study does not determine the relationship between the

variations on concentrations of the contaminants and the depth from which the sample

is collected due to limited samples to be used in sediment dating. However, analysis

on the relationship between the length of the tributary and the concentrations of the

analytes are examined.

1.5 Theoretical Framework

Natural sediments are organic and inorganic materials found at the bottom of a

water body. These may include clay, silt, sand, gravel, decaying organic matter, and

shells among other things.

Sediments can become contaminated in a number of ways. Urban runoff that

discharges to surface waters often contains polycyclic aromatic hydrocarbons

(PAHs), oil and grease, and heavy metals. Agricultural runoff may contain nutrients

and pesticides. Industrial spills and releases, especially those that occurred before

controls were in place, can add contamination into the water. Chemicals that are

denser than water, such as polychlorinated biphenyls (PCBs) and some pesticides,

will sink to the bottom of water bodies and directly contaminate sediments.

Atmospheric deposition of substances such as mercury is another source of sediment

contamination as is the discharge of contaminated groundwater through the sediments

to the overlying surface water (USEPA 1999 and USEPA 2005).

The classes of contaminants that are most common in sediment contamination are

pesticides, PCBs, PAHs, and to a lesser extent dissolved phase chlorinated

hydrocarbons. With the right geochemical conditions heavy metals and metalloids

can also occur in sediments or precipitate into them.

The contamination of sediment with heavy metals, even in small concentrations

may lead to serious environmental problems. Heavy metals can either be absorbed

onto sediments or accumulated by benthic organism to toxic levels; the bioavailability

and subsequent toxicity of the metals are dependent upon the various forms and

amount of the metal bound to the sediment matrices.

Sediment investigations are generally conducted in two parts. The first uses

common sampling and analytical procedures to determine if the total concentrations

of contaminants are high enough to warrant concern. The underlying assumption is

that all the contaminant is bioavailable. If the data indicate there may be a problem,

then the second part of the investigation is done. This part focuses on bioavailability

and determining whether there is physical evidence of an impact such as less

biodiversity in the impacted sediments and the presence of the chemicals in the tissue

of flora and fauna (USEPA 2005).

Historical background about the deposition of sediment is of great importance as

it may determine possible sources at a specific time frame. However, in the event that

these data are not available radiometric dating may be employed. In the past few

decades many applications of natural and man-made radionuclides to the

determination of sediment accumulation rates have been documented. These methods

have provided useful information in some cases, but in many others they have met

with only limited success, since post-depositional processes (such as biological and

physical mixing, erosion) confounded the record. One of these radionuclides is 210Pb.

Pb-210 (half-life 22.3 years) is a naturally occurring radioisotope of the U-238

family. 210Pb dating determines the age of the sediment within 100 to 150 years of

range. The calculations of ages are achieved on the basis of CRS model or CIC model

depending on the source of Pb-210 fluxes.

1.6 Conceptual Framework

Figure 1.1 Summary of the Process Steps

Collection of Samples

Preparation of Samples

Laboratory analysis

210Pb dating Heavy Metal Analysis

PCB Analysis

Interpretation of Data

Drawing of Conclusion

1.7 Definition of Terms and Acronyms

1. Anthropogenic – created by people or caused by human activity

2. Benthic – relating to the bottom of a sea or lake or to the organisms that live

there.

3. Bioavailability – the rate at which a substance is absorbed or becomes available

at site.

4. Congener – a term in chemistry that refers to one of many variants or

configurations of a common chemical structure.

5. Effects Range-Low (ERL) – indicative of concentration below which adverse

effects rarely occur.

6. Effects Range-Median (ERM) – indicative of concentration above which effects

frequently occur.

7. Estuary – the widening channel of a river where it nears the sea, with a mixing of

fresh water and salt (tidal) water

8. NOAA – National Oceanic and Atmospheric Administration

9. Non-point or diffuse sources – are discharges that cannot be identified as

coming from one definitive location or point.

10. 210Pb dating – radiometric dating

11. PCB – polychlorinated biphenyl

12. Point source – is an input that enters a body of water at a definitive location and

can usually be quantified.

13. Sediments – solid fragments of inorganic or organic material that come from the

weathering of rock and are carried and deposited by wind, water, or ice.

14. SQG – Sediment Quality Guidelines

15. Tributary - a stream that flows into a larger stream or other body of water

CHAPTER 2

REVIEW OF RELATED LITERATURE AND STUDIES

2.1 Related Literature

2.1.1 Sediments

Columbia Encyclopedia defines sediments as mineral or organic particles that are

deposited by the action of wind, water, or glacial ice. They are commonly subdivided

into three major groups-mechanical, chemical, and organic.

Mechanical, or clastic, sediments are derived from the erosion of earlier formed

rocks on the earth's surface or in the oceans. These are then carried by streams, winds,

or glaciers to the site where they are deposited. Streams deposit sediment in

floodplains or carry these particles to the ocean, where they may be deposited as a

delta. Ocean sediments, especially in the form of turbidites, are usually deposited at

the foot of continental slopes (see oceans). Glaciers carry sediment frozen within the

mass of the ice and are capable of carrying even huge boulders (erratics).

Chemical sediments are formed by chemical reactions in seawater that result in

the precipitation of minute mineral crystals, which settle to the floor of the sea and

ultimately form a more or less chemically pure layer of sediment. For example,

evaporation in shallow basins results in a sequence of evaporite sediments, which

include gypsum and rock salt.

Organic sediments are formed as a result of plant or animal actions; for example,

peat and coal form by the incomplete decay of vegetation and its later compaction.

Deep-ocean sediment known as pelagic ooze consists largely of the remains of

microscope organisms (mostly foraminifera and diatoms) from the overlying waters

as well as minor amounts of windblown volcanic and continental dust. Limestones

are commonly formed by the aggregation of calcite shells of animals.

Categories of Sediments

Sediments can be divided into three categories; framework bed load, matrix bed

load and suspended bed load.

Framework bed load creates the structure of the bed. They are large particles that

are moved only during large flow events.

The matrix bed load refers to the part of the bed material that is small enough to

be frequently entrained by low to moderate flow but is large enough to settle out of

the water column in lower velocities. They incorporate the sand and the silt size

material.

The suspended bed load is the smallest size class of the total sediments of the

fluvial system (RCA III 1995,)

Sources of Sediments and Sediment Contaminants

Aquatic sediments are principally derived from weathering processes, with major

transportation from terrestrial sources under high runoff from storms and floods. In

addition, discharges from urban, industrial and mining activities are potential sources

of particulates. Anthropogenic contaminants, including metals, organics and nutrient

elements are associated with particulate and dissolved inputs to natural waters. It is

important to distinguish between point source and diffuse inputs. (Australian and

New Zealand Guidelines for Fresh and Marine Water Quality Volume 2, 2000)

A point source is an input that enters a body of water at a definitive location and

can usually be quantified. Factories (industrial) and municipal wastewater outfalls are

examples of point source discharges. Wastewater sources may include domestic

wastewater infiltration and inflow, and wastewater from commercial sources such as

canneries, agricultural operations, etc. Non-point or diffuse sources, on the other

hand, are discharges that cannot be identified as coming from one definitive location

or point. The discharge often enters the waterways through overland runoff, through a

large number of smaller drainage pipes, or by precipitation travelling through the

surface of the land and water.

(http://www.njdwsc.com/prbwmp/wma3/doc/wca_report/wma3wca_3-1.pdf)

Sediment Properties

a. Physics of Aquatic Sediments

In the second volume of Australian and New Zealand Guidelines for Fresh and

Marine Water Quality (2000), physical properties, such as grain size and density, are

deemed as important in sedimentation and transport processes. Sediments are a

heterogeneous mixture of particles ranging from millimetre to submicron in size.

Typically, sediments are characterized as coarse material, clay/silt and sand fractions,

on the basis of separations using 2 mm and 63 μm sieves. Particles >2 mm may

consist of shells, rocks, wood, and other detrital materials, and are usually not a

source of bioavailable contaminants (Mudroch et al. 1997). The clay/silt fraction has

a high surface area and because of its surface chemistry is more likely to adsorb

organic and heavy metal contaminants. Particles <63 μm are more common in the gut

of sediment-ingesting biota (Tessier et al. 1984).

The size of the sediment is also important to bioturbidation or organism

burrowing since it affects the ease and depths to which organisms can burrow.

Simpson et al (2005) said that the different feeding and burrowing behaviors of

organisms affects how they sort particles, enrich or deplete organic matter, inject

oxygen into localized sediments and alter contaminant fluxes from sediments.

b. Sediment Chemistry

Sediment chemistry is controlled by redox conditions (dissolved oxygen,

sulfides), pH, and the geochemistry of sediment particles. Contaminants are

distributed over a range of geochemical phases, as well as being dissolved in the

associated sediment pore waters, and the nature of these associations and

sediment/pore water equilibria will determine their ultimate bioavailability. (Simpson

et al, 2005)

Sediment pore water pH is the master variable controlling the speciation and

bioavailability of metals. (Australian and New Zealand Guidelines for Fresh and

Marine Water Quality Volume 2, 2000). S. Goodwin et al (1987) found out in their

study that progressively lower pH values inhibit microbial hydrogen-producing and -

consuming processes within sedimentary ecosystems.

Schmid-Araya (2004) discussed that redox potential is measured with respect to a

hydrogen electrode and it is called the Eh. A negative sign indicates reducing

conditions whereas a positive sign indicates oxydising conditions. The chemical

diagenesis of sediments comprises those chemical reactions taking place during and

after burial of sedimentary material. Reactions can be divided into two categories:

biogenic and abiogenic, whether or not reactions are mediated by microorganisms.

The early diagenesis is largely controlled by bacteria. Moreover, pore water

chemistry is dominated by these reactions, which in general control the Eh and pH of

sedimentary environments.

2.1.2 Impact of Heavy Metal and PCB Contamination in Human Health and the

Environment

Heavy metal contamination in sediments poses great threat not only to human

race but also to the environment. Sediments act as both carrier and potential sources

of contaminants in an aquatic environment. Heavy metals can either be adsorbed onto

sediment or accumulate by benthic organism to a toxic level, the bioavailability and

subsequent toxicity of the metals are dependent upon the various forms and amount

of the metal bound to the sediment matrices.

Karen Greaney (2005) listed the common heavy metal pollutants and their

beneficial and detrimental effects including toxicity and hazards.

• Copper (Cu)

Copper is an essential micro-nutrient required in the growth of both plants and

animals. In humans, it helps in the production of blood hemoglobin. In plants, copper

is especially important in seed production, disease resistance and regulation of water.

Copper is indeed essential, but in high doses it can cause anemia, liver and kidney

damage, and stomach and intestinal irritation. About half of copper contribution to the

environment from urbanization is from automobiles. Brakes release copper. Motor oil

also tends to accumulate metals as it comes into contact with surrounding parts as the

engine runs, so oil leaks become another pathway by which metals enter the

environment. Copper normally occurs in drinking water from copper pipes, as well as

from additives designed to control algal growth. While copper’s interaction with the

environment is complex, research shows that most copper introduced into the

environment is, or rapidly becomes stable and results in a form which does not pose a

risk to the environment. In fact, unlike some man-made materials, copper is not

magnified in the body nor bio-accumulated in the food chain.

• Lead (Pb)

Lead occurs naturally in the environment. However, most lead concentrations that

are found in the environment are a result of human activities, natural and

anthropogenic sources. Exposure to lead can result in a wide range of biological

effects depending on the level and duration of exposure. Various effects occur over a

broad range of doses, with the developing young and infants being more sensitive

than adults. Lead poisoning, which is so severe as to cause evident illness, is now

very rare. For as is known, lead fulfils no essential function in the human body, it can

merely do harm after uptake from food, air or water. Lead is a particularly dangerous

chemical, as it can accumulate in individual organisms, but also in entire food chains.

• Mercury (Hg)

Mercury is a toxic substance which has no known function in human biochemistry

or physiology and does not occur naturally in living organisms. Monomethylmercury

is probably the most common toxic form of mercury found in the marine

environment. It has been known to travel through marine food chains and causes

damage to human consumers. All mercury that is released in the environment will

eventually end up in soils or surface waters.

• Zinc (Zn)

Zinc occurs naturally in air, water and soil, but zinc concentrations are rising

unnaturally, due to addition of zinc through human activities. Most zinc is added

during industrial activities, such as mining, coal and waste combustion and steel

processing. Water is polluted with zinc due to the presence of large quantities present

in the wastewater of industrial plants. This wastewater is not purified satisfactory.

One of the consequences is that rivers are depositing zinc-polluted sludge on their

banks. Zinc may also increase the acidity of waters. Some fish can accumulate zinc in

their bodies, when they live in zinc-contaminated waterways. When zinc enters the

bodies of these fish it is able to bio magnify up the food chain. Water-soluble zinc

that is located in soils can contaminate groundwater.

• Polychlorinated biphenyls (PCB)

Polychlorinated biphenyls are mixtures of up to 209 individual chlorinated

compounds (known as congeners). There are no known natural sources of PCBs.

PCBs are either oily liquids or solids that are colorless to light yellow. Some PCBs

can exist as a vapor in air. PCBs have no known smell or taste. Many commercial

PCB mixtures are known in the U.S. by the trade name Aroclor. PCBs have been used

as coolants and lubricants in transformers, capacitors, and other electrical equipment

because they don’t burn easily and are good insulators. PCBs do not readily break

down in the environment and thus may remain there for very long periods of time.

PCBs can travel long distances in the air and be deposited in areas far away from

where they were released. In water, a small amount of PCBs may remain dissolved,

but most stick to organic particles and bottom sediments. The most commonly

observed health effects in people exposed to large amounts of PCBs are skin

conditions such as acne and rashes. Studies in exposed workers have shown changes

in blood and urine that may indicate liver damage. PCB exposures in the general

population are not likely to result in skin and liver effects. Most of the studies of

health effects of PCBs in the general population examined children of mothers who

were exposed to PCBs. (ATSDR, 2001)

2.1.3 Sediment Quality Guidelines

Sediment quality guidelines are very useful to screen sediment contamination by

comparing sediment contaminant concentration with the corresponding quality

guideline, provide useful tools for screening sediment chemical data to identify

pollutants of concern and prioritize problem sites and relatively good predictors of

contamination. These guidelines are chemical specific and do not include biological

parameters.

a. Ontario Ministry of Environment Screening Level Guidelines

The Ontario Ministry of Environment developed sediment quality guidelines

based on screening level concentrations from data for a range of local sediments and

benthic biota (ANZECC, 2000). The ministry had set three levels of guidelines, the

no-effect-level or NEL, the low-effect-level or LEL and the severe-effect-level or

SEL.

The NEL is point at which the chemicals in the sediments do not affect fish or

sediment-dwelling organisms. There is no expected effect on the water quality for

there is no transfer of chemicals on the food chain. This level is considerably clean.

The LEL is the lowest that toxic effects become apparent and the SEL represents

concentrations that could effectively eliminate most of the benthic organisms and

pollutes the sediments. If the sediment is above SEL, testing must be made to find out

if the sediment is acutely toxic.

In line with the three levels of guidelines, the levels of contaminations for

possible metals were set by Ontario Ministry of Environment. Values are shown in

Table 2.1.

Table 2.1 Ontario Ministry of Screening Level Guidelines

Contaminant Low Severe

Metals (mg/kg dry wt.)

Copper 16 110

Lead 31 250

Mercury 0.2 2

Zinc 120 820

Organic (µg/kg dry wt.)a

Total PCBs 70 5300

a - Normalized to 1% organic carbon

b. National Oceanic and Atmospheric Administration Sediment Quality

Guidelines

NOAA-SQG was derived through its National Status and Trends (NS&T)

program using considerable amounts of chemical data on sediments. These data are

from studies performed throughout North America and were based on measures of

biological effect associated with toxicants. With these, the effects-range-low or ERL

and the effects-range-median or ERM, was determined. They used 10th percentile of

the total number of studies as the concentration that indicates adverse effects for

below ERL values. The 50th percentile was used as a guideline for above ERM

indicating adverse effect. The concentration that falls under the ERL value is

considered non-toxic and pollution-free sediments. Concentration in between the ERL

and ERM value is considered desirable and generally clean. However, concentration

above ERM value is a state that effectively eliminates most of the benthic organisms

and the sediment is considered heavily polluted.

Table 2.2 ERL and ERM guideline values for trace metals and organic

compounds

Contaminant ERL ERM

Metals (ppm dry wt.)

Copper 34 270

Lead 46.7 218

Mercury 0.15 0.71

Zinc 150 410

Organic (ppb dry wt.)

Total PCBs 22.7 180

c. Australian and New Zealand Environment and Conservation Council

(ANZECC) Guidelines

ANZECC Sediment Quality Guideline is an effect-based guideline. It uses local

database of studies based on effects data on local species on Australian biota for local

sediment samples. Australia and New Zealand have recently revised their guidelines

for fresh and marine water quality and have included, for the first time, a

consideration of sediment quality. The guidelines contain two concentrations, the

ISQG-Low concentration (or trigger value) and the ISG-High concentration. The

trigger value is a threshold concentration, and below this concentration the frequency

of adverse biological effects is expected to be very low. The ISQG-High

concentration is intended to represent a concentration, above which adverse

biological effects are expected to occur more frequently. Exceeding the trigger value

concentrations does not necessarily mean that adverse biological effects will occur in

the sediments, but further investigation should be undertaken to confirm this.

Table 2.3 ANZECC Sediment Quality Guideline

Contaminant ISQG – Low ISQG – High

Metals (mg/kg dry wt.)

Copper 65 270

Lead 50 220

Mercury 0.15 1

Zinc 200 410

Organic (µg/kg dry wt.)a

Total PCBs 23

a - Normalized to 1% organic carbon

d. Hong Kong Sediment Quality Guideline

The Sediment Quality Guidelines of Hong Kong were primarily adopted or

modified from the United States and other temperate countries even though Hong

Kong is located in the tropics. Hong Kong also has unique climate and hydrology

that make adopting SQGs from other countries not desirable. Unlike most tropical

countries, Hong Kong has marked seasonality with warm, wet summers and cold,

dry winters.

The Sediment quality guideline values were derived from an extensive

international database including effects range low (ERL), effects range median

(ERM), and the Puget Sound Estuary Program. The chemical classes currently

measured include metals, metalloids, PAHs, PCBs, and tributylin. Two SQGs were

developed for each chemical or class of chemicals. The lower chemical exceedance

level (LCEL) represents a value below which contaminants in the sediment are not

expected to have adverse biological effects, whereas the upper chemical exceedance

level (UCEL) represents a value above which toxicity is likely.

Table 2.4 Sediment quality guideline values lower-concentration

exceedance level (LCEL) and upper concentration exceedance level (UCEL) of

Hong Kong

ContaminantLCEL (Lower Chemical

Exceedance Level)

UCEL (Upper Chemical

Exceedance Level)

Metals (mg/kg dry wt.)

Copper 65 110

Lead 75 110

Mercury 0.5 1

Zinc 200 270

Organic (µg/kg dry wt.)

Total PCBs 23 180

2.1.4 Analytical Techniques for Sediment Analysis

a. Atomic Absorption Spectrometry

Atomic absorption methods measure the amount of energy (in the form of photons

of light, and thus a change in the wavelength) absorbed by the sample. Specifically, a

detector measures the wavelengths of light transmitted by the sample (the "after"

wavelengths), and compares them to the wavelengths, which originally passed

through the sample (the "before" wavelengths). A signal processor then integrates the

changes in wavelength, which appear in the readout as peaks of energy absorption at

discrete wavelengths. Any atom has its own distinct pattern of wavelengths at which

it will absorb energy, due to the unique configuration of electrons in its outer shell.

This allows for the qualitative analysis of a pure sample.

This technique is used for single element analysis of aqueous samples and on

solid samples which are introduced in the form of a slurry. Quantitation is performed

using single element standard solutions from which calibration curves are prepared.

(V.R.R Annaredy et al, 2003)

b. Alpha Spectrometry

This technique is carried out instrumentally using planar ion-implanted silicon

detectors after radiochemical separation of the α-emitting radionuclide of interest.

The complete procedure involves dissolution of the sample, chemical separation and

co-precipitation of the α-emitter onto a carrier source. The typical sample size is 1 to

10 gram of ash from soil, biological material, or air filter. Quantitation is carried out

by energy and efficiency calibration of the α-spectrometer using calibrated sources of

the radionuclide of interest in the same geometry as the sample source. The detection

limit is typically 0.5 mBq per sample.

2.1.5 Sediment Dating

210 Pb Dating

In the Bear Lake Project (1998), lead 210 (210Pb) a radioactive form of lead,

having an atomic weight of 210 was used to date sediment samples. It is one of the

last elements created by the radioactive decay of the isotope uranium-238 (238U). 210Pb

forms naturally in the sediments and rocks that contain 238U, as well as in the

atmosphere, a by-product of radon gas. Within 10 days of its creation from radon, 210Pb falls out of the atmosphere. It accumulates on the surface of the earth where it is

stored in soils, lake and ocean sediments, and glacial ice. The 210Pb eventually decays

into a non-radioactive form of lead. 210Pb has a half-life of 22.3 years, which means

that after 22.3 years, only half of the original amount is undecayed. If the sediment

layers are undisturbed, then as the sediment ages it slowly loses its radioactivity. We

can determine how old a sediment layer is by how much 210Pb it contains. It takes

about 7 half-lives, or 150 years for the 210Pb in a sample to reach near-zero

radioactivity. For younger sediments we can use an isotope of lead (lead-210).

Models for 210 Pb Dating

Because 210Pb is produced both in the atmosphere and in sediments, it is necessary

to make basic assumptions about the origin of 210Pb in the sample of interest.

Basically, 210Pb accumulates in sediments and undergoes decay. In an ideal situation

where sedimentation is constant and undisturbed, the concentration of 210Pb with

depth is related as

P ( x )=Poe−λxV

where Po = concentration of 210Pb at the surface at time t = 0

λ = decay constant for 210Pb (0.03114 y-1)

V = sedimentation velocity based on an exponential fit to the measured

210Pb, P(x), with depth x (Carroll, et al., 1995).

The two most commonly used models as Noller J. (2000) discussed are listed

below:

a. Constant Rate of Supply Model

The CRS model is based on the assumptions that (1) the unsupported 210Pb is

supplied at a constant rate to sediments through time, (2) the initial 210Pb

concentration in the sediment is variable, and (3) the influx rate of sediment is

variable (Goldberg, 1963). Initially developed by Goldberg (1963), this model seeks

to determine the age of any given depth within a sediment column. In order to do so,

the integrated activity of 210Pb below this depth must be calculated. First, the initial

concentration of unsupported 210Pb [Co(t)] in sediment of t years in age must

conform to the argument that

Co(t) r(t) = constant

where r(t) (in g cm-2 yr-1) = dry-mass sedimentation rate at time t (Appleby and

Oldfield, 1978). Second, at any depth (x) within the sediment column, the activity of

unsupported 210Pb (Cx) is related by the law of radioactive decay:

Cx=Coe−λt

where λ = decay constant for 210Pb. From this equation, Appleby and Oldfield

(1978) develop a relation for the age of a deposit at depth x:

t=1λ

logAoAx

where Ao = total unsupported 210Pb activity in the sediment column

Ax = total unsupported 210Pb activity in the sediment column beneath

depth x.

b. Constant Initial Concentration Model

The CIC model is based on the assumptions of (1) constant initial concentration

(activity) of unsupported 210Pb in a sediment sample, and (2) a constant influx rate

of sediment (Goldberg, 1963).

t=1λ

logCoCx

This model is compromised by a variable sedimentation rate, which is typical for

most depositional systems. Hence, the CIC model is rarely used and only then in

support of the CRS model results.

2.2 Related Studies

2.2.1 Sediment Quality Guidelines

Sediments become an increasing concern in the past decades. Assessment of

contamination of these sediments can be done using established guidelines or criteria.

But without a national criterion or other widely-applicable numerical tools, National

Oceanic and Atmospheric Administration, scientists found it difficult to estimate the

possible toxicological significance of chemical concentration in sediments. Sediment

Quality Guidelines were needed quickly for interpretation of data from the ongoing

studies; thus, data from studies performed throughout North America were compiled

to ensure broad applicability of guidelines. Guidelines were developed for as many

chemicals as the data would warrant. SQGs were needed that would estimate the safe

concentration like concentrations below which effects were not likely and which

effects were more likely. Data from each study were arranged in order of ascending

concentrations. Study endpoints in which adverse effects were reported were

identified. The 10th percentile are considered “Effects Range-Low” (ERL), indicative

of concentration below which adverse effects rarely occur. The 50th percentile were

named as “Effects Range-Median” (ERM) values, representative of concentration

above which effects frequently occur.

However, not every country or region have their own Sediment Quality

Guideline. Thus, recent studies conducted were compared to different SQGs available

and established. Praveena et al. (2008) studied the state of heavy metal concentration

in Mengkabong Lagoon, Sabah, Malaysia and applied six empirically derived

sediment quality guidelines to assess the quality of mangrove sediments. Samples

were collected at high and low tides and characterized by atomic absorption

spectrometry. The metals data were compared with Washington Department of

Ecology (WDOE), Sediment Quality Guidelines (1995), Australian and New Zealand

Environment and Conservation Council (ANZECC, 1999), Swedish Environmental

Sediment Quality Guideline (SQG, 1996), Screening Quick Reference Table

(SQUIRT), Portuguese Legislation on the Classification of Dredged Materials in

Coastal Zones and Interim Sediment Quality Guideline for Hong Kong. The metal

concentrations were generally low, displaying relatively higher concentration at high

tides compared to low tides. The interim sediment quality values for Hong Kong were

selected, being the most appropriate guideline that meets the prioritization criteria

consistent with international initiatives and regulations. The guideline verified that all

metals are below Interim Sediment Quality Value-low.

2.2.2 Sediment Heavy Metal Contamination

Kaushik et al. (2009) conducted a study on analysis of heavy metals in water,

sediments and littoral flora in the river of Yamuna, Haryana, India. For the sediments,

enrichment factor for each of the heavy metal of interest (Cd, Cr, Fe, Ni) was

calculated based on the background value of the metal taken as a world average of the

metal in the earth’s crust. Other important physico-chemical properties of river water

and sediments were also analyzed and interrelationships of all the parameters with

heavy metal concentration were studied. Results showed that the Yamuna river is

significantly contaminated with Ni and Cd, major anthropogenic sources of which

were identified as electroplating and textile dyeing industries located along the banks

of the river.

A study was conducted by Ahmad et al. (2009) to determine the concentration of

selected heavy metals in Sungai Kelantan, Kelantan, Malaysia. The river water

quality was measured together with metal concentrations in sediments in order to

confirm to quality of the river. Result of water quality analysis indicated that Sungai

Kelantan is characterized by excellent water quality. Total metal concentrations in

sediment were lower as compared to the concentration in earth crust for baseline

concentration for heavy metals.

Parizanganeh et al. (2007) studied the heavy metal pollution in sediments from

the Southern Caspian Coast. This research concentrated on investigating the

concentrations and spatial distribution of metals in the near shore sediments along the

Iranian coast of the Caspian Sea. The samples were sieved and three grain size

fractions from each sample plus fourteen bulk samples were selected for analysis of

metals. Laboratory analysis of the samples utilized the Cold Acetic Protocol,

followed by Inductively Coupled Plasma Optical Emission Spectroscopy. Data

obtained were analyzed using statistical techniques. Linear regression analysis

demonstrated that the grain size of sediments was not a major factor controlling the

concentrations and spatial distributions of heavy metals. The researcher noted that it

could be due to the fact that the analyzed grain samples were not in the very fine

material range (<0.063 mm) which numerous investigators found to be associated

with the highest concentrations of heavy metals.

Concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cd and Co were determined by

Prudente et al. (1994) in surface and core sediments collected from Manila Bay and in

surface sediments collected from Manila Bay and in surface sediments from

inflowing rivers. Core profiles revealed highly fluctuating and enriched Pb, Cd, Zn

and Cu concentrations on the surface, suggestive of recent inputs coming from

anthropogenic sources. Concentrations of Pb, Zn and to a lesser extent Cu and Cd

were higher in riverine sediments as compared with marine sediments, which may be

attributed to the proximity of these riverine sites to pollutant sources. Comparison of

metal concentration levels obtained with other areas in the world revealed elevated

values for Pb and Cd, indicating a considerable amount of pollution in the area.

Polychlorinated Biphenyls (PCBs) were collected using sediment cores at seven

sites in the Venice Lagoon and within the canals of the industrial area and were

analyzed in order to assess the chronology of pollution in and its present trends. M.

Frignani et al (2003) found that the surficial concentration of PCBs is very high (more

than 2049 µg/kg) only in the Brentella Canal, probably due to a recent contaminating

episode. Very high values downcore (up to 41639 µg/kg) can be found in the

industrial parts of the area, especially in the canals Lusore-Brentelle and Salso.

Lagoon samples are much less contaminated (2.7-123 µg/kg), being influenced only

ocassionally by polluted sediments resuspended from the canals. Sediment

chronology shows that the delivery of contaminants peaked in the 1970s to early

1980s, decreasing since at most sites. Congener profiles distinguish PCBs in two

main categories: heavy congeners characterize a baseline pollution, probably due to a

large variety of sources within the lagoon system, whereas a mixture of light PCBs

was discharged into the canals Brentella and Salso.

2.2.3 Sediment Dating

Manila Bay is considered as one of the marine pollution hot spots in the Seas of

East Asia. 210Pb dating of its sediment can provide a historical perspective of its

pollution loading. However, the validity of 210Pb dating in a complex dynamic

coastal system of Manila Bay may come into question. Land-based sediment input

can be high and physical and biological processes can possibly disturb the sediment

layers. In this report, the 210Pb profiles of sediment cores from different parts of the

bay are presented. The linear sedimentation rates are shown to be higher in the recent

past and are also variable across the bay. The largest change in sedimentation rate,

coincided with the occurrence of a volcanic eruption in 1991 and is shown by

applying a variant of the CIC model in sedimentation rate calculations in which the

main assumption is that at each stage in accumulation, the unsupported 210Pb

concentration is constant regardless of changes in net sediment accumulation. (Sta.

Maria et al, 2008).

Sediment coring for subsequent elemental analysis and radionuclide dating is an

effective way to reconstruct sedimentation and contamination chronologies in

sheltered marine environments, as well as in determining the baseline concentrations

or background values. Of four sediment cores collected in Strangford Lough, as

studied by Strong and Service (2008) three showed clear spikes in the mass

accumulation of sediment in the late 1970s and early 1980s. These brief periods of

heavy sedimentation also coincided with periods of conspicuous change in particle-

size parameters in two cores. Monthly meteorological data for Northern Ireland

suggest that wind speeds and rainfall were also above average for this period.

However, the majority of the annualised meteorological data failed to correlate with

the particle-size parameters or the sedimentation rate. Heavy-metal analysis indicated

that most metals are near a predicted background concentration, although Cd appears

to be particularly enriched, and Cd concentrations continue to increase in the most

recent deposits.

CHAPTER 3

METHODOLOGY

3.1 Description of the Study Area

Figure 3.1 Aerial View of Estero de Balete and its vicinity (Adapted from Google

Earth, February 19, 2010)

Estero de Balete is one of the tributaries of Pasig River, with approximately 530

meters in length, 14 meters width and 3 meters depth, flows from Taft Avenue to

Romualdes Street, Ermita, Manila.

3.2 Sampling and Analysis

3.2.1 Sample Collection and Preparation

Samples are collected in ten different sections as shown in Figure 3.2, 3.3 and 3.4,

of Estero de Balete at three sample sites per section. Collection of samples starts at

about 26.5 meters from Taft Avenue at every 53 meters until Romualdes Street and

collection will be done during low tide. A boat, to be coordinated with the Adamson

University Physical Facilities Office and the Metropolitan Manila Development

Authority (MMDA), is used for sediment sampling at the mid portion and at every 3.5

meters from the bank of the tributary by Core Sampling method.

Figure 3.2 Sampling plan

Figure 3.3 Sampling plan

Figure 3.4 Sampling plan

Figure 3.5 Core Sampling

A 6 feet high by 2 inches in diameter PVC sampling tube, sharpened and edge

beveled, is forced to the sediment bed vertically until about 1 meter of the sampling

tube is filled with sediments as shown in Figure 3.5. Overlying water is removed from

the sediments through a small hole bored on the pipe approximately just above the

sample before it is placed in the sample container. The hole is not to be more than 5

mm in diameter to induce laminar flow of water and to prevent mixing of the surface

sediments. The sediments are removed from the sampling tube through the use of

another PVC pipe, 6 feet high by 1.5 inches in diameter, pre-marked with the desired

thickness for analysis as shown in Figure 3.6. Sediment sample for 210Pb dating and

for contaminant analysis are to be taken from the collected sediments as shown in

Figure 3.7. All of the samples are collected on a glass container and are labeled

accordingly with the site, and the depth from where it was collected. All glassware,

for precautionary measures for trace metal analysis, are soaked overnight with 20%

HNO3 and then rinsed with water.

Figure 3.6 Removal of Sediments

Figure 3.7 Sediment samples in core sampler

Coarse materials found in the sediment sample are hand-picked (e.g.

debris, rocks, shells, wood > 2mm diameter) as these may interfere in the analyses.

Samples for contaminant concentration analysis collected are sun-dried for 48 hours.

Sediment samples for lead-210 dating are stored at 4 °C. Sediment samples are

ground for homogeneity using mortar and pestle (non carbon) and analyzed for

concentration of contaminants.

3.2.2 Acid digestion of Sediment Samples for Metal Analysis

About ¾ of the sample for contaminant concentration analysis is used for metal

analysis. Every 0.5 gram of sediment sample is taken into acid digestion by adding 10

ml of Aqua Regia (1:4 v/v HNO3:HCl) in a beaker. The beaker is heated on a hot

plate for 2 hours with swirling, repositioning, and rinsing of the beaker wall for 1

hour. Samples are then transferred into centrifuge tubes and diluted into a final

volume of 30 ml of deionized water for every 0.5 gram samples used.

In the procedure, it is assumed that the entire sample is digested. Otherwise,

centrifugation is employed to separate the undigested sediments.

3.2.3 Metal Analysis of Sediment Samples

Atomic Absorption Spectrophotometer (AAS) experimental method of research is

used for the heavy metal characterization of Estero de Balete sediments.

3.2.4 Polychlorinated Biphenyl (PCB) Analysis

The remaining ¼ of the sample for contaminant concentration analysis is used for

total PCB analysis. The sample is weighed into a clean glass bottle, where anhydrous

sodium sulfate (pre-dried at 400 °C) is added to obtain a free flowing mixture, a

solution of surrogate compounds spiked onto the mixture and 100 ml per 20 gram

sample of extraction solvent 1:1 (v/v)(pesticide residual grade)

dichloromethane/acetone. The bottles covered with Teflon-lined caps are tumbled for

2 h. Extracts are filtered using a microfiber filter paper and concentrated to

approximately 1 ml on a water bath at 90 °C.

3.2.5 Polychlorinated Biphenyl Analysis of Sediment Samples

Gas Chromatography – microcell electron capture detection using large volume

injections (25 µL) experimental method of research is used in polychlorinated

analysis.

3.2.6 Lead-210 dating

Lead-210 dating is conducted using Constant Rate of Supply (CRS) model at

Philippine Nuclear Research Institute (PNRI) using alpha spectrometer. Pb-210 is

determined by measurement of its daughter nuclide, Polonium-210, which decays by

alpha particle emission. Sample digestion involves acid treatment of dried 1 g

samples spiked with a 208Po tracer for chemical yield measurement followed by

spontaneous plating onto a silver disc. 208Po and 210Po is detected by counting in alpha

particle spectrophotometry system using a surface barrier silicon detector for a

minimum of 24 h. Measurements of radionuclides is standardized and calibrated

using IAEA Sediment Reference Standards IAEA-135 and IAEA-300.

References

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