Pergamon PII: S0045-6535(96)00228-7

Chemosphere, Vol. 33, No. 5, pp. 939-960, 1996 Copyright © 1996 Elsevier Science Ltd

Printed in Great Britain. All rights reserved 0045-6535/96 $15.00 + 0.00

TOXICITY IDENTIFICATION OF POCOMOKE RIVER POREWATER

GIAN GUPTA" and MAKESH KARUPPIAH Department of Natural Sciences

University of Maryland Eastern Shore Princess Anne, MD 21853

( R e c e i v e d i n U S A 2 4 F e b r u a r y 1 9 9 6 ; a c c e p ~ d 2 9 M a y 1 9 9 6 ) ABSTRACT

Toxicants associated with sediments affect many natural aquatic ecosystems. Pocomoke River (PR) is one of the 150 rivers and streams that feed its sediment into the Chesapeake Bay. The objective of this study was to use USEPA Toxicity Identification Evaluation (TIE) tests to identify toxicants in the sediment- porewater of PR. Samples from three depths (0-7.7, 7.8-15.4 and 15.5-23.1 cm) at four sites (1.6 km upstream of, adjacent to and 1.6 and 3.2 km downstream of the municipal sewage treatment plant (STP) outlet) were collected. The porewater samples were tested for toxicity (EC~) using the Microtox" marine luminescent bacteria (Vibrio fischeri), TOXITRAK TM toxicity test (Inhibition-%I), and Ceriodaphnia dubia (48-h survival-%S). High toxicity values (EC~ = 12.8%, % I = 93 and % S = 11) were observed for the samples collected at the site 1.6 km downstream of the STP outlet, which is near an intensive agricultural area including a poultry farm. Toxicity reduced significantly with increasing depth at every sampling site. Toxicity also decreased with distance from the most contaminated site both upstream and downstream. Qualitative MetPLATE TM analyses showed that toxic forms of metals were present in all the sampling sites except for the site 1.6 km upstream of the STP outlet. Phase I TIE tests suggested that the toxicity was due to oxidants, metals and organic compounds. Phase II TIE tests identified chlorine (total) and heavy metals [zinc (Zn), lead (Pb), copper (Cu), cadmium (Cd) and Arsenic (As)]. Polychlorinated biphenyls (PCBs) and organochlorine pesticides were found in PR porewater. Copyright © 1996 Eisevier Science Ltd

INTRODUCTION

The adsorption of biogenic and anthropogenic organic

chemicals onto particles and continuous deposition of pollutants

make sediments temporary or long-term sinks for many toxicants

(Knezovich et al., 1987). Agricultural runoff is a major source of

contaminants to the Chesapeake Bay and its tributaries (Helz and

Huggett, 1987). The quality of the Chesapeake Bay is being harmed

by the inflow of nutrients, sediments and toxic contaminants from

"Author for corresDondence

939

940

surrounding environments (USAEC, 1993). The sedimentation rate in

the Chesapeake Bay ranges from 1.6-12.6 mm/year (Kerhin et al.,

1988). The PR, a Chesapeake Bay tributary on the Eastern Shore of

Maryland, runs through the city of Pocomoke and is one of the 150

rivers and streams that feed into the Bay. Agricultural runoff is

the main source of contaminants along the Eastern shore of Maryland

(USGS, 1992). Herbicides, pesticides and heavy metals are the

important toxicants that contaminate the bay system due to

agricultural runoff (Buttleman and Lovejoy, 1987). The

concentrations of pesticides and metals in the sediments were

relatively high near the Chincoteague Inlet area (Morton and

Wolfin, 1993), located near our study site.

The PR receives runoff from extensive agricultural practices.

Along with non-point agricultural runoff, a small STP is another

source of contaminants into the PR. The STP began operating in 1971

and serves about 4,000 persons. The STP receives an average daily

inflow of 1.2 x 104 Lpd including effluents (i x 105 Lpd) from

poultry processing, food, gun manufacturing, plastic, wood and

other small scale industries.

TIE tests (USEPA 1989, 1991) can be used to characterize

classes of toxicants and identify specific toxic compounds in

porewaters or elutriates from contaminated sediments (USEPA 1991a;

Berigan and Ankley, 1991). These TIE tests include initial

toxicity, baseline toxicity, pH adjustment, aeration, filtration,

Cis-column solid phase extraction (Cls SPE), sodium thioeulfate

(Na2S203) addition, ethylenediaminetetraacetate ligand (EDTA

chelation), graduated pH and zeolite tests to identify the

toxicants in porewaters. No information is available in the

lite~rature on the toxicity of PR porewater.

OBJECTIVES

The objectives of this study were: i) to use USEPA (1989,

1991} approved TIE tests to identify toxic components in porewater

of PR, and 2) to determine the changes in toxicity with sediment

depth and distance from the municipal STP outlet and the poultry

farm discharge.

MATERIALS AND METHODS

STUDY SITE AND SAMPLE COLLECTION:

Fig. 1. Sampling sites in PR

941

Agricultural area

farm

Agricultural area

l ~ v e r

Origin - 1 6 k m

Residential a r e a

~-age treatment plant outlet

942

Four study sites (Fig. 1), 1.6 km upstream of the STP (PR1),

at the STP outlet (PR2), 1.6 km downstream of the STP (PR3;

adjacent to a poultry farm) and 3.2 km downstream of the STP (PR4;

receiving agricultural runoff) were selected for study. A Peterson

classmate dredge was used to collect the sediment samples. Sediment

samples were separated into 0-7.7, 7.8-15.4 and 15.5-23.1 cm

depths, stored in polythene ziplock bags and shipped on ice to the

University of Maryland Eastern Shore Environmental Sciences

Research Lab. Porewater was separated from the sediment by

centrifugation in an IEC (Needham Heights, MA) Model 2K centrifuge

at 5000G for 30 min using teflon centrifuge bottles. Porewater and

sediment samples were then stored in glass and plastic sample

bottles, respectively at 4°C. Microtox, Toxitrak, MetPLATE and

Ceriodaphnia dubia were used to measure the toxicity of PR

porewater.

MICROTOX R TOXICITY TEST:

Toxicity of porewater was measured using Microtox Toxicity

Analyzer 2055 (Beckman Instruments, Carlsbad, CA) (Bulich, 1984).

The ECs0 was calculated using the software Version 7.8 supplied by

Beckman.

TOXITRAK TM TEST:

Inhibition of dye reduction (Liu, 1989) with PR porewater was

measured.

METPLATE TM TEST FOR HEAVY METAL TOXICITY:

Presence of toxic heavy metals in the porewater was measured

qualitatively using microbial assay - MetPLATE, Group 206

Technologies, Gainesville, FL (Bitton et al., 1994).

ceri¢~aphnia dubia TEST:

Six animals (USEPA, Duluth, MN) grown in spring water using

Ward's (Rochester, NY) daphnia feed, were used for testing the

toxicity (survival - 48 h) of the porewater (30 mL) (hardness

1.84±0.67 mg/L of CaC03) (Mount and Norberg, 1984; USEPA 1989a). All

toxicity tests were done using the porewater without dilution, with

no change in pH (initial pH - 6.3±0.2) and at room temperature

(22±1°C) following the recommended standard procedures.

TIE TESTS:

The physico-chemical characteristics of PR porewater sample

from all sites and depths were measured using standard methods

(APHA, 1989). USEPA (1991) Phase I TIE test procedures were used to

determine the toxicity of the porewater using Microtox R and

Ceriodaphnia dubia. In Phase II TIE tests (USEPA, 1989), metal

concentrations in porewater were analyzed using a Perkin-Elmer

(Norwalk, CT) Atomic Absorption Spectrophotometer with graphite

furnace (detection limits for Pb, Cu, Cd and As were 0.05, 0.02,

0.003 and 0.2 ~g/L, respectively) or flame emission (detection

limit for Zn was 0.1 mg/L). Nitric acid digestion procedure was

used for preparing samples for analyzing heavy metals in the

por~aater (APHA, 1989; Hoke etal., 1993).

Organic compounds in PR porewater were analyzed using Hewlett

Packard 5890 A (San Fernando, CA) Gas Chromatograph (GC) with

Eleo~ron Capture Detector. A 50 ~L sample of surrogate was used as

internal standard (including blank). The surrogate was a mixture of

PCB #14 (3,5-dichlorobiphenyl) = 0.1698 ~g/mL + PCB #166

(2,3,4,4'5,6-hexachlorobiphenyl)= 0.146 ~g/mL. The oven conditions

943

944

were set at 100°C initially for 2 min then to 170°C at 4°C/min, then

to 280°C at 3°C/min; final holding time was 5 min at 280°C for PCBs.

A mixture of Alltech (Deerfield, IL) pesticide standards was used

for pesticide analyses (APHA, 1989). The oven conditions were set

at 50°C initially for 2 min then to 280°C at 10°C/min then to 310°C

at 4°C/min; final holding was 4 min for pesticides. A splitlees 5%

phenylmethyl silicon capillary (60 m length) column (DB-5, i.d.:

0.32 mm) and split/splitless 5% phenylmethyl silicon capillary (25

m length) column (i.d.: 0.2 mm) was used for PCB and pesticide

analyses, respectively. The carrier gas was hydrogen for PCBs and

helium for pesticides. The amount of sample injected was 2 #L

(APHA, 1989).

STATISTICAL ANALYSES

Randomized complete block (Gomez and Gomez, 1984) was used as

the experimental design. Analysis of Variance (ANOVA) and least

significant differences (LSD) were calculated (p~ 0.05) using SAS

(1985). All the experiments were replicated three times.

RESULTS AND DISCUSSION

Mean values of the porewater characteristics from different

sites are given in Table 1. The PR porewater was slightly acidic,

soft and had low dissolved oxygen. Total chlorine concentrations

ranged from 0.44-1.58 mg/L in the porewater.

TOXICITY TESTS:

The toxicity of PR porewater (7.7 cm depth), using various

tests, was highest at PR3 and lowest at PR1 (Table 2). Toxicity

(EC~%) to light emitting marine bacterium Vibrio fischeri at PR3

was 12.8%. Similar results have been reported on porewater toxicity

Table i: Physico-chemical characteristics of porewater (7.7 cm depth)

Site

Characteristic

PR1

PR2

PR3

PR4

(LSD)"

pH

6.1

6.0

Conductivity (mS/cm)

0.75

0.76

Turbidity (NTU)

2

3

Dissolved Oxygen (mg/L)

0.24

0.22

Salinity (%)

0.01

0.03

Nitrogen-ammonia (mg/L)

8 9

Nitrogen-nitrate (mg/L)

1.0

1.4

Oxid.Red. Potential (my)

89

90

Hardness (mg/L of CaCO3)

1.91

2.51

Total Chlorine (mg/L)

0.53

1.58

Sulfide (mg/L)

0.43

1.55

Phosphate (mg/L)

3.95

4.15

6.4

6

.5

(0.1

6)

0.74

0.74

(0.002)

4 4

(NV

")

0.1

8

0.2

0

(NV

)

0.0

7

0.0

9

(0.0

13

)

4

3

(3.77)

0.4

0

.4

(0.2

8)

85

84

(5.09)

1.5

1

.44

(0

.02

6)

0.7

8

0.4

4

(NV

)

0.3

8

0.3

7

(HV

)

3.0

1

3.0

0

(0.1

46

)

"Least significant differences (p~ 0.05)

"No value

946

Table 2: Toxicity (mean values) of PR porewater (7.7 cm depth)

Sampling Site

Toxicity test PR1 PR2 PR3 PR4 LSD"

Microtox (EC~%) 85 58 13 37 3.62

Toxitrak (% I) 14 58 93 66 7.11

C. dubia (48hr-%S) 94 55 11 39 12.84

MetPLATE P(-)'" Y(+) Y(+) Y(+)

" Least significant differences

°'P(-) Purple (negative), Y (+) Yellow (positive)

Table 3: Changes in porewater toxicity (Microtox EC~%, mean values')

with depth

Depth

(cm)

Site

PR1 PR2 PR3 PR4 LSD"

7.7 85 58 13 37 3.62

15.4 92 63 26 46 1.52

23.1 97 71 39 62 2.43

LSD 2.48 2.92 3.26 2.49

"All means are significantly different (PS 0.05) from one another

"'Least significant differences

(EC~ = 52.1-63.3%) of Lower Fox River, WI (Hoke et al., 1992) and

Grand Calumet River, IN, (EC~ = 0.3-93.8%) (Hoke et al., 1993). The

toxicity of all sites was significantly (p~ 0.05) different from

each other. Similar results were observed using Toxitrak TM (%

Inhibition) and Ceriodaphnia dubia (48 hr % survival) tests; both

these tests confirmed that PR3 was the most toxic and PR1 was the

least toxic site. MetPLATE TM tests were positive for all the sites

except for PR1 porewater showing thereby that the toxicity at this

site was not from heavy metals.

Mean values of EC~ (Microtox) ranged from 13-97% (Table 3).

The porewaters with EC~values ranging from 0-19, 20-39, 40-59, 60-

79, 80-99 and >100% have been classified as extremely toxic, very

toxic, toxic, moderately toxic, slightly toxic and non toxic,

respectively (Bennett and Cubbage, 1992). Since EC~ value for PR3

is 12.8%, it can be considered to be an extremely toxic site;

agricultural farm runoff including runoff from the poultry farm

were the main sources of pollutants at this site. The sites PR4 and

PR2 were less toxic than PR3 at the three depths studied and PRI

was the least toxic of all the four sites. The toxicity decreased

with increasing distance (in both directions because of the tides)

from PR3 and also with increasing depth indicating a reduction in

anthropogenic sources of pollution. The toxicity of the porewater

at PR2 was higher than the toxicity of the porewater at PR1 because

of tlhe discharge of pollutants from the STP at PR2. The PR4 is more

toxic than PR1 from the transport of pollutants from both PR2 and

PR3. The pollutants from point sources in the freshwater sediment

systems transport, disperse and dilute with increasing distance

947

948

from point of origin (Hellawell, 1988); the PR with a n average

salinity of 0.05±0.04 is a tidal river. Ankley etal., (1990) and

Dieter et al., (1994) reported some inconsistencies with theuse of

Microtox. However Microtox test (EC~) has been used in several

other sediment toxicity studies and was found to be highly

reproducible and less time consuming (Hoke et al., 1993 and

Toussaint et al., 1995); hence Microtox was used for further TIE

tests; Ceriodaphnia dubia was also used as an additional test.

TIE TESTS:

Phase I TIE test results for the most toxic sample (PR3 - 7.7

cm depth) are shown in Table 4. Reduction in toxicity (of the

porewater) was found with aeration (at initial pH), graduated pH

(11) test, sodium thiosulfate addition, EDTA chelation and C~s

column tests. These Phase I TIE test results suggest that the PR

porewater toxicity was due to pH sensitive toxicants/volatile

compounds and/or oxidants, heavy metals and organic compounds. The

Ceriodaphnia dubia test results were similar to that of Microtox i

test (Table 4). Hellawell (1988) reported that the toxicity of

metals is high in soft water than hardwater; the PR porewater is

very soft (CaCO 3 hardness - 1.84 mg/L, Table 1). Hoke et al., (1993)

found that water hardness (upto 3000 mg/L of Caco3) did not have any

effect on the Microtox test. Also the change in pH (6.8 - 8.4) does

not affect ~Microtox' toxicity significantly (Yates and Porter,

1984). Sodium thiosulfate addition decreased the toxicity possibly

because of the presence of oxidants or metals in the porewater.

Further, Phase II TIE tests revealed that the main toxicants

in PR porewater were total chlorine and heavy metals. The AAS

949

Table 4: Phase I TIE tests (site PR3)

Mlcrotox

Toxicity characterization tests EC~ %

Ceriodephnia

dubia

tS

Initial toxicity

Aeration (pH.._~.,)

Filtration (p . I -~)

EDTA chelation

Na2S~O 3 addition

Post Cil SPE test

Graduated pH test

p.3

pH~

PHIl

Zeolite

za (o .68 )"

49 ( 0 . 0 8 )

Z4 ( 0 . 2 3 )

88 (Z .63)

5? ( 0 . 2 0 )

?z (o.8z)

Z (NV")

z3 (o .68 )

27 (0.24)

z5 (o .zT)

zz (o .?z)

28 ( 0 . 3 7 )

22 ( 0 . 9 4 )

s3 ( z . ? 3 )

6? ( 0 . 6 3 )

?? (o.8e)

NS oel

11 (o.~z)

33 (1 .41 )

17 (1 .63 )

"Values in parentheses are standard deviations

"*No value

"*'No survival

950

analyses of the porewater showed high concentrations of Zn followed

by Pb, Cu, Cd and As (Table 5). The concentrations of Zn, Pb, Cu

and Cd were found to be significantly different (ps 0.05) at all

sites and depths. The metal concentrations in the porewater were

highest at the 7.7 cm depth and lowest at the 23.1 cm depth. The

porewater from PR3 had the highest metal concentrations (Table 5).

The concentrations of Zn, Pb, Cu and Cd ranged from 1.39 - 4.62,

0.57 - 0.74, 0.017 - 0.108 and 0.001 - 0.025 mg/L, respectively.

Arsenic was found in PR3 (7.7 and 15.4 cm depth) and PR4 (7.7 cm

depth) ranging from 0.004 - 0.007 mg/L. Arsenic is present both in

herbicides (Hellawell, 1988) and poultry litter (Gupta and Kelly,

1990). The site PR3 is 1.6 km downstream of the STP outlet but

adjacent to a poultry farm which appears to be the source of metals

into the river along with other agricultural runoff. Berndtsson

(1990) studied metal accumulation in sediments receiving sewage

effluents and extensive drainage from agricultural areas in River

Hoje, Sweden, and found high concentrations of Zn (1700 ppm), Pb

(180 ppm) and Cu (740 ppm). High concentration of Zn in PR

porewater can be both from agricultural runoff and from the

industries that contribute to the sewage influent. The Delmarva

Peninsula, where PR is located, is ranked 4th in the nation in

poultry and litter production (9,500 tons per day); land disposal

of large amounts of poultry litter can contribute heavy metals (Cu,

Cd and As) to waters and sediments after precipitation. A ton of

poultry litter contains approximately 320 ppm Cu, 35 ppm As and Pb

each and smaller amounts of Cd and Hg (Gupta and Kelly, 1990).

Cadmium tends to accumulate in sediments near sewage outfalls

951

Table 5: Porewater metal concentrations (mg/L)

METALS SITES

PR2 Depth PR1 ( c u )

7.7 2.12 ~

15.4 1.73 k

23.1" 1.39 ~

LSD 0.24

7.7 0.58 ~

15.4 0.57 k

23.1 0.57 ~

LSD 0.0076

7.7 0.026 ~

15.4 0.020 k

23.1 0.017 ~

LSD 0.002

7.7 0.001 ~

15.4 0.001"

23.1 0.001"

LSD 0.0001

7.7 ND °°

15.4 ND

23.1 ND

PR3 PR4 LSD °

3.05 ~ 4.62 p 3.18 ~ 0.87

Zn 2.61 = 3.51 M 2.73 ~ 0.12

1.91 ~ 2.892 2.56 ~ 0.14

0.02 0.12 0.08

0.59 e 0.74 p 0.58 b 0. 002

Pb 0.586 0.59 M 0.58 jr 0. 007

0.57 ~ 0.59 ~ 0.58 ~ 0. 002

0.0076 0.0037 0.0076

0.064 ~ 0.i08 ~ 0.070 ~ 0.006

Cu 0.035" 0.076 ~ 0.045 ~ 0.005

0. 022 ~ 0. 0552 0. 028 ~ 0. 002

0.004 0.006 0.008

0. 002 ~ 0. 025 ~ 0. 003 ~ 0. 0006

Cd 0. 0 0 2 ~ 0. 003 ~ 0. 002 ~ 0. 0002

0. 001 ~ 0. 002 ~ 0. 001 ~ 0. 0001

0. 0001 0.0047 0.0002

ND 0. 007 0. 004

AS ND 0. 005 ND

ND ND ND

~eaat significant differences

"Not detected

a d g J b e h k cfil

columnwiae comparisons within blocks; means with same letters a~e not significantly different (p~ 0.05)

m n o p rowwiae comparisons within blocks; means with same letters q r 8 t - are not significantly different (p~ 0.05) u v w x

952

(Swartz et al., 1985). Cadmium in PR porewater seems to be from the

sewage outfall and the poultry farm runoff.

The porewater from PR2 had higher concentrations of metals

than the porewater from PR1 but lower than the porewater from PR3.

This increase in the metal contents at PR3 can be from both the

transport of metals from PR2 (STP) and from the poultry and

agricultural farm runoff. The porewater from PR4 had higher

concentration of metals than the porewater from PR1. The

concentration of metals decreased with increasing depth at each of

the sites indicating a reduction in anthropogenic sources of

pollution with increasing time. High concentration of Cd at only

PR3 (7.7 cm depth) suggests point-sources of pollution of

relatively recent origin (Hershelman et al., 1981). The

concentration of all metals (Zn, Pb, Cu and Cd) exceeded the

freshwater acute criteria for protection of aquatic life (USEPA,

1991b) and also the range of the priority pollutants in porewater

(Straub, 1989)(Table 6). The mean concentration of Zn in the PR

porewater was higher compared with the EC~ (Microtox) value

reported for Zn by Chou and Hee (1994) (Table 6).

Phase I TIE tests suggested reduction in toxicity after Na~S203

addition; the PR porewater was analyzed for total chlorine. Even

though Na2S203 additions are designed to characterize the toxicity

of oxidants such as chlorine and its derivatives, this decrease in

the toxicity can also be from the removal of metals such as Cu and

Cd (USEPA, 1991). The total chlorine was found to be 0.53, 1.58,

0.78 and 0.44 mg/L at PR1, PR2, PR3 and PR4, respectively. Highest

concentration of total chlorine was found near the STP outlet

Table 6: Comparison of metal concentrations in PR porewater with Microtox "EC~"

concentration, EPA freshwater acute criteria and priority pollutant range in

porewater (#g/L)

Metal

Mean conc. of

Metal ion

Freshwater

Range

metals in PR

Microtox EC~ conc.

acute criteria

(Straub, 1989)

porewater

(Chou and Hee, 1994)

(USEPA, 1991b)

(7.7 cm depth)

Zn

3

24

0

10

00

1

20

9

0-3

30

Pb

6

00

6

00

8

3

30

-40

0

Cu

7

0

80

0

18

1

1-

49

Cd

8

20

00

0

4 2

- 7

954

(PR2), confirming the STP as a source of toxicity. The Pocomoke STP

uses only a primary settling tank and the effluent is then treated

with a large dose of chlorine. Total residual chlorine is toxic to

different organisms and the LC~of chlorine induced oxidants to mud

crab - Panopeus herbstii - is 10 mg/L (Breisch et al., 1984). over

140 STPs along the Chesapeake Bay use chlorine as disinfectant; the

total residual chlorine has been reported to be as high as 19 mg/L

in these effluents (Breisch et al., 1984).

Solid phase extraction (Cj8) test suggested that the toxicity

is from nonpolar organic compounds. The analysis of porewater (PR3,

7.7 cm depth) showed the presence of organochlorine pesticides

(Table 7). The concentration of heptachlor was higher than the

criteria for the freshwater aquatic life protection (Table 7). The

concentrations of other pesticides and PCBs found in PR porewater

were lower than the criteria for freshwater aquatic life

protection. Nearly 1.4 million kg of pesticides are used annually

for agricultural purposes on the Delmarva Peninsula (USGS, 1992).

Site PR3 is near an intensive agricultural area accounting for

these long term persistent pesticides in the porewater. Hoke et

al., (1993) reported lindane, chlordane and heptachlor

concentrations ranging from 0.1-0.7, 0.1-3.1 and 0.5-4.6 ~g/L in

porewater of Grand Calumet River, IN.

A total of 50 PCB congeners were found in the porewater (PR3,

7.7 cmdepth); the 10 congeners with the highest concentrations are

listed in Table 8. PCBs are ubiquitous in the environment and are

of anthropogenic nature (Potter and Pawliszyn, 1994). PCB

contamination in Michigan harbor has been attributed to non-point

Table 7: Pesticides and PCBs in PR porewater (PR3, 7.7 cm depth)

and comparison with freshwater aquatic life protection

criteria

955

Pesticides ng/L

Fresh water aquatic

life protection criteria

(ng/L) (Sittig, 1985)

Lindane 80

(B HCH 0.19

HCH) 0.17

Heptachlor 19.66 3.8

Chlordane 4

(t-Chlordane 0.21

c-Chlordane) 0.27

PCBs 12.88 14

Table 8: PCB congeners concentration in PR porewaters

Congener Name Mass (ng/L)

Number

105 2,3,3',4,4'-pentachlorobiphenyl 0.905

99 2,2',4,4',5-pentachlorobiphenyl 0.545

149 2,2',3,4',5',6-hexachlorobiphenyl 0.532

180 2,2',3,4,4',5,5'-heptachlorobiphenyl 0.445

28 2,4,4'-trichlorobiphenyl 0.289

182 2,2',3,4,4',5,6'-heptachlorobiphenyl 0.217

190 2,3,3',4,4',5,6-heptachlorobiphenyl 0.214

151 2,2',3,5,5',6-hexachlorobiphenyl 0.198

76 2',3,4,5,-tetrachlorobiphenyl 0.178

174 2,2', 3'3',4,5,6'-heptachlorobiphenyl 0.178

956

source pollution (Baudo and Muntau, 1990). PCBs were used as heat-

transfer fluids, hydraulic fluids, solvent extenders, plasticizers,

organic diluents and dielectric fluids (Abramowicz et al., 1993).

Polychlorlnated biphenyls might have been transported from other

sources such as leaking capacitor/transformer. Since the post-Cls

test showed a reduction in toxicity and the analyses of the

porewater revealed the presence of pesticides and PCBs, these

compounds may also be contributing to the toxicity of the

porewater.

The following conclusions can bemadebesed on the results of

this study:

1. The sampling site, 1.6 km downstream of the STP outlet had the

most toxic porewater compared to the other sites 1.6-3.2 km away

both downstream or upstream. The porewater from this site was

"extremely toxic"; sites 1.6 km upstream or downstream were

"very toxic" and the site 3.2 kmupetream was "sllghtly toxic".

2. Phase I and II TIE tests and porewater analyses for organic

compounds identified total chlorine and metals from STP, metals

and pesticides (from agrlcultural sources) as the contaminants

in the PR porewater.

3. The concentrations of heavy metals and the toxicity of the PR

porewater decreased with depth (7.7 > 15.4 > 23.1 cm) and with

increasing distance from the most polluted site.

ACKNOWLEDGEMENTS:

Thanks are due Dr. Joel Baker and Mr. Eric Nelson, CBL,

Solomons, MD, for their help with PCB and pesticide analyses.

957

REFER~/~CES :

Abramowicz, D.A., M.J. Brenan, H.M. Vandort and E.L. Gallagher.

1993. Environ. Sci. Technol. 27: 1125-1131.

Am. Public Health Assoc. 1989. Standard Methods for the Examination

of Water and Wastewater. 17th ed. Washington, D.C.

Ankley, G.T., G.S. Peterson, J.R. Amato and J.J. Jenson. 1990.

Environ. Toxicol. Chem. 9: 1305-1310.

Baudo, R. and H. Muntau. 1990. In: Sediments: Chemistry and

Toxicity of In-place Pollutants. R. Baudo, J. Giesy and H.

Muntau (Eds), Lewis Publishers Inc., Chelsea, MI. pp. 1-14.

Bennett, J. and J. Cubbage. 1992. Washington State Dept. of

Ecology, Olympia, WA. pp. 334-392.

Berigan, M.K.S. and G.T. Ankley. 1991. Environ. Toxicol. Chem. 10.

925-939, 1991.

Berndtsson, R. 1990. Water Resour. Res. 26(7): 1549-1558.

Bitton, G., K. Jung and B. Koopman. 1994. Environ. Contamin.

Toxicol. 27: 25-28.

Breisch, L.L., D.A. Wright and D.M. Powell. 1984. In: Chlorine and

the Chesapeake Bay. A Review of Research Literature, M. Leffler

(Ed}, A MD Sea Grant Pub1. MD. pp. 11-113.

Bulich, A.A. 1984. In: Toxicity Screening Procedures Using

Bac~erial Systems. D. Liu and B.J. Dutka (Eds), Marcel Dekker,

New York, NY. pp. 55-64.

Buttleman, L.P. and J.C. Lovejoy. 1987. In: Contaminant Problems

and Management of Living Chesapeake Bay Resources. S.K.

Majumdar, L.W. Hall, Jr. and H.M. Austin, (Eds), The Penn. Acad.

of Science, Typehouse of Easton, Phillipsburg, NJ. pp. 485-511.

958

Chou, C.C. and S.S.Q. Hee. 1994. Environ. Toxicol. Chem. 13(7):

1177-1186.

Dieter, C.D., S.J. Hamilton, W.G. Duffy and L.D. Flake. 1994.

J. Fresh Water Eco. 9 (4): 271-280.

Gomez, K.A. and A.A. Gomez. 1984. In: Statistical Procedures for

Agricultural Research. K.A. Gomez and A.A. Gomez (Eds), Wiley-

Interscience Publ., New York, NY. pp. 1-84.

Gupta, G.C. and P. Kelly. 1990. Water, Air and Soil Pollut. 53:

113-145.

Hellawell, J.M. 1988. Environ. Pollut., 50: 61-85.

Helz G.R. and R.J. Huggett. 1987. In: Contaminant Problems and

Management of Living Chesapeake Bay Resources. S.K. Majumdar,

L.W. Hall, Jr. and H.M. Austin (Eds), The Penn. Acad. of

Science. Typehouse of Easton, Phillipsburg, NJ. pp. 270-297.

Hershelman, G.P., H.A. Schafer, T.K. Jan and D.R. Young. 1981.

Mar. Poll. Bull., 12: 131-134.

Hoke, R.A., J.P. Giesy and R.G. Kreis, Jr. 1992. Ecotoxicol.

Environ. Saf. 23: 343-354.

Hoke, R.A., J.P. Giesy, M. Zalik and M. Unger. 1993. Ecotoxicol.

Environ. Saf. 26: 86-112.

Kerhin, R.T., J.P. Halka, D.V. Wells, E.L. Hennessee, P.J.

Blakeslee, N. Zoltan and R.H. Cuthbertson. 1988. Dept. of

Natural Resources, MD Geological Survey, Report 48.

Knezovich, J.P., F.L. Harrison and R.G. Wilhelm. 1987. Water, Air

and Soil Pollut. 32: 233-245.

Liu# D. 1989. Toxicity Assess. 4: 399-404.

Morton, J,M. and J.P. Wolfin. 1993. Ocean city, Maryland and

vicinity water resources reconnaissance study. Prepared for US

Army Corps of Engineers Baltimore District, MD. pp. 1-20.

Mount, D.I. and T.J. Norberg. 1984. Environ. Toxicol. Chem. 3: 425-

434.

Potter, D.W. and J. Pawliszyn. 1994. Environ. Sci. Technol. 28:

298-305.

SAS" Statistics. 1985. SAS" User's Guide: Version 5. SAS institute,

Cary, NC.

Sittig, M. 1985. Handbook of Toxic and Hazardous Chemicals and

Carcinogens. 2nd ed. Noyer Publ. Park Ridge, NJ. pp. 203-739.

Straub, C.P. 1989. Practical Handbook of Environmental Control. CRC

Press, Inc., Boca Raton, FL. pp. 229-241.

Swartz, R.C., G.R. Ditsworth, D.W. Schults and J.O. Lamberson.

1985. Marine. Environ. Res. 18: 133-153.

Toussaint, M.W., T.R. Shedd, W.H.V. Schalic and G.R. Leather. 1995.

Environ. Toxicol. Chem. 14(5): 907-915.

United States Army Environmental Center. 1993. Department of the

Ansy Chesapeake Bay Intiative FY 92 Progress Report. RCS-EPA

1004. Aberdeen Proving Ground, MD.

United States Environmental Protection Agency. 1989. Methods for

aquatic toxicity identification evaluations. Phase II toxicity

identification procedures. EPA/600/3-88/035, Duluth, MN.

United States Environmental Protection Agency. 1989a. Short term

met=hods for estimating the chronic toxicity of effluents and

receiving waters to fresh water organisms. 2nd ed. EPA/600/4-

89/001, Cincinnati, OH.

United States Environmental Protection Agency. 1991. Methods for

959

960

aquatic toxicity identification evaluations. Phase I toxicity

characterization procedures. EPA/600/6-91/003, Duluth, MN.

United States Environmental Protection Agency. 1991a. Sediment

Toxicity Identification Evaluation: Phase I (Characterization),

Phase II (Identification) and Phase III (Confirmation)

Modifications of Effluent Procedures. EPA/600/6-91/O07, Duluth,

MN.

United States Environmental Protection Agency. 1991b. Technical

Support Document for Water Quality-based Toxics Control.

EPA/505/2-90-001, Washington, D.C.

United States Geological Survey. 1992. Are Fertilizers and

Pesticides in the Groundwater?. A case study of the Delmarva

Peninsula, Denver, CO.

Yates, I.E. and J.K. Porter. 1984. In: Toxicity Screening

Procedures Using Bacterial Systems. D. Liu and B.J. Dutka (Eds),

Marcel Dekker, New York, NY. pp. 77-88.