National Water-Quality Assessment Program

Concentrations of Selected Organochlorine Compounds in 

Fish Tissue in the Mississippi Embayment Study Unit:

Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and 

Tennessee, 1995-99

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2004-5006
Concentrations of Selected Organochlorine 

Compounds in Fish Tissue in the 

Mississippi Embayment Study Unit: 

Arkansas, Kentucky, Louisiana, 

Mississippi, Missouri, and Tennessee, 

1995-99

By Suzanne R. Femmer, Richard H. Coupe, Billy G. Justus, and Barbara A. Kleiss

National Water-Quality Assessment Program

Scientific Investigations Report 2004-5006

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Femmer, S.R., Coupe, R.H., Justus, B.G., and Kleiss, B.A., 2004, Concentrations of selected organochlorine compounds 

in fish tissue in the Mississippi Embayment Study Unit: Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and 

Tennessee, 1995-99: U.S. Geological Survey Scientific Investigations Report 2004-5006, 36 p.
iii

FOREWORD

The U.S. Geological Survey (USGS) is committed to serve the Nation with accurate and timely scientific information that helps enhance and protect the overall quality of life, and facilitates effective management of water, biological, energy, and mineral resources. Information on the quality of the Nation’s water resources is of critical interest 

to the USGS because it is so integrally linked to the long-term availability of water that is clean and safe for drinking and recreation and that is suitable for industry, irrigation, and habitat for fish and wildlife. Escalating population growth and increasing demands for the multiple water uses make water availability, now measured in terms of 

quantity and quality, even more critical to the long-term sustainability of our communities and ecosystems.

The USGS implemented the National Water-Quality Assessment (NAWQA) Program to support national, regional, 

and local information needs and decisions related to water-quality management and policy. Shaped by and coordinated with ongoing efforts of other Federal, State, and local agencies, the NAWQA Program is designed to answer: 

What is the condition of our Nation’s streams and ground water? How are the conditions changing over time? How 

do natural features and human activities affect the quality of streams and ground water, and where are those effects 

most pronounced? By combining information on water chemistry, physical characteristics, stream habitat, and 

aquatic life, the NAWQA Program aims to provide science-based insights for current and emerging water issues. 

NAWQA results can contribute to informed decisions that result in practical and effective water-resource management and strategies that protect and restore water quality.

Since 1991, the NAWQA Program has implemented interdisciplinary assessments in more than 50 of the Nation’s 

most important river basins and aquifers, referred to as Study Units. Collectively, these Study Units account for 

more than 60 percent of the overall water use and population served by public water supply, and are representative 

of the Nation’s major hydrologic landscapes, priority ecological resources, and agricultural, urban, and natural 

sources of contamination. 

Each assessment is guided by a nationally consistent study design and methods of sampling and analysis. The 

assessments thereby build local knowledge about water-quality issues and trends in a particular stream or aquifer 

while providing an understanding of how and why water quality varies regionally and nationally. The consistent, 

multi-scale approach helps to determine if certain types of water-quality issues are isolated or pervasive, and allows 

direct comparisons of how human activities and natural processes affect water quality and ecological health in the 

Nation’s diverse geographic and environmental settings. Comprehensive assessments on pesticides, nutrients, volatile organic compounds, trace metals, and aquatic ecology are developed at the national scale through comparative 

analysis of the Study-Unit findings. 

The USGS places high value on the communication and dissemination of credible, timely, and relevant science so 

that the most recent and available knowledge about water resources can be applied in management and policy decisions. We hope this NAWQA publication will provide you the needed insights and information to meet your needs, 

and thereby foster increased awareness and involvement in the protection and restoration of our Nation’s waters. 

The NAWQA Program recognizes that a national assessment by a single program cannot address all water-resource 

issues of interest. External coordination at all levels is critical for a fully integrated understanding of watersheds 

and for cost-effective management, regulation, and conservation of our Nation’s water resources. The Program, 

therefore, depends extensively on the advice, cooperation, and information from other Federal, State, interstate, 

Tribal, and local agencies, non-government organizations, industry, academia, and other stakeholder groups. The 

assistance and suggestions of all are greatly appreciated.

 Robert M. Hirsch

 Associate Director for Water
iv
v

Contents

FOREWORD ................................................................................................................................................... iii

ABSTRACT ..................................................................................................................................................... 1

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

Purpose and Scope ............................................................................................................................. 2

Description of the Study Unit ............................................................................................................. 2

MATERIALS AND METHODS ...................................................................................................................... 4

Sample Collection ................................................................................................................................ 4

Age Determination ............................................................................................................................... 4

Sample Preparation and Analysis .................................................................................................... 4

Data Analysis ........................................................................................................................................ 6

Reporting Limits and Quality-Control Procedures .......................................................................... 6

Field Quality Assurance ...................................................................................................................... 7

RESULTS AND DISCUSSISON .................................................................................................................... 8

DDT ...... .................................................................................................................................................. 9

Relation with Ancillary Data .............................................................................................................. 9

Comparison with National Standards and Guidelines ................................................................. 12

SUMMARY AND CONCLUSIONS ............................................................................................................ 16

REFERENCES ............................................................................................................................................... 16

Figures

 1. Map showing physiographic provinces, ecoregions, and fish-tissue sampling sites of 

the Mississippi Embayment Study Unit .................................................................................... 3

2. Map showing geologic age of surficial deposits of the Mississippi Embayment Study 

Unit ................................................................................................................................................. 5

3. Graph showing surrogate recoveries for samples analyzed by the National WaterQuality Laboratory, 1995-99 ........................................................................................................ 7

4. Map showing percent detections of 28 organochlorine compounds in whole fish from 

52 sampling sites in the Mississippi Embayment Study Unit, 1995-99 .............................. 10

Figures 5-8: Boxplots showing:

5. PCB concentrations in whole fish from large (greater than 1,310 km2) and small (less 

than 1,310 km2) drainage basins in the Mississippi Embayment Study Unit, 1995-99 ..... 11

6. Selected organochlorine concentrations in whole fish collected from sampling sites in 

which the surficial soils of the drainage basin are primarily of the Holocene, Pleistocene, or mixed geologic age in the Mississippi Embayment Study Unit, 1995-99. ......... 13

7. Selected organochlorine concentrations between classes of soil permeability, in the 

Mississippi Embayment Study Unit, 1995-99 ......................................................................... 14

8. Selected organochlorine concentrations between bed-sediment particle size, in the 

Mississippi Embayment Study Unit, 1995-99 ......................................................................... 15
vi

Tables

 1. Description of fish-tissue sampling sites in the Mississippi Embayment Study Unit, 

1995-99. ........................................................................................................................................ 20

2. Organochlorine and PCB concentrations in whole fish, from sampling sites in the Mississippi Embayment Study Unit, 1995-99 ................................................................................ 22

 3. Physical characteristics of composited fish-tissue samples collected from streams in 

the Mississippi Embayment Study Unit, 1995-99 .................................................................. 26

 4. Concurrent samples analyzed by the National Water Quality Laboratory and the 

National Contaminant Biomonitoring Program, 1995 ........................................................... 28

 5. Relative percent difference for selected organochlorine compounds between 

duplicate and multi-year fish-tissue samples collected in the Mississippi Embayment 

Study Unit, 1995-99 .................................................................................................................... 32

 6. Results of analysis of variance on weight, age, and total length for fish collected in 

subsequent years ...................................................................................................................... 33

 7. Statistical summary of concentrations of organochlorine compounds and PCBs 

analyzed in fish tissue collected in the Mississippi Embayment Study Unit, 1995-99 .... 34

 8. DDT and DDT degradate concentrations, total DDT concentrations, and DDT, DDE, and 

DDD to total DDT ratios for fish-tissue samples collected in the Mississippi 

Embayment Study Unit, 1995-99 .............................................................................................. 35
vii

CONVERSION FACTORS, ABBREVIATIONS, AND ACRONYMS

Multiply By To obtain

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

square kilometer (km2

) 0.3861 square mile (mi2)

cubic meter per second (m3

/s) 35.31 cubic foot per second (ft3/s)

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

BHC Benzene hexachloride

BEST Biomonitoring of Environmental Status and Trends

DCPA Dimethyl 2,3,5,6-tetrachloroterephthalate

DDD Dichlorodiphenyldichloroethane

DDE Dichlorodiphenyldichloroethylene

DDT Dichlorodiphenyltrichloroethane

E Estimated

GC Gas chromatography

GCP Gulf Coastal Plains

HCB Hexachlorobenzene

HCH Hexachlorocyclohexane

MAP Mississippi Alluvial Plain

MISE Mississippi Embayment

MRL Method reporting limit

MVLP Mississippi Valley Loess Plains

NAWQA National Water-Quality Assessment

NAS/NAE National Academy of Sciences and National Academy of Engineering

NCBP National Contaminant Biomonitoring Program

NWQL National Water Quality Laboratory

NYFF New York Fish Flesh Criteria

PCB Polychlorinated Biphenyl

RPD Relative Percent Difference

SP Southeastern Plains

TDDT Total DDT

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey
viii
ABSTRACT

Whole fish were collected at 52 sites during 1995-99 to 

evaluate the occurrence and distribution of selected organochlorine compounds in the Mississippi Embayment Study 

Unit. Samples were collected as part of the U.S. Geological 

Survey National Water Quality Assessment Program. From 

5 to 8 fish were collected at each site; the fish were composited, and an aliquot of the tissue was analyzed for 28 organochlorine compounds, which included pesticides, pesticide 

degradates, and polychlorinated biphenyls. The use of these 

organochlorine compounds has been discontinued or severely 

restricted within the United States, but the continued detection 

of these compounds or their degradates in the air, water, soil, 

and biota in national surveys, coupled with known environmental problems associated with these compounds (such as a 

long half-life and the propensity to accumulate in living tissue), is cause for continued interest in their environmental fate. 

At least one organochlorine compound was detected in every 

fish-tissue sample, and as many as 15 different compounds 

were detected in some. The most frequently detected compounds were the degradates of p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT); p,p’-dichlorodiphenyldichloroethylene 

(p,p’-DDE) was detected in every sample above the method 

reporting limit, and p,p’-dichlorodiphenyldichloroethane 

(p,p’-DDD), was detected in 94 percent of the samples. Polychlorinated biphenyl compounds and dieldrin were detected in 

83 and 78 percent of fish-tissue samples, respectively. Because 

these were whole fish samples, the results are not directly 

comparable to human health standards, which are based 

on fish fillets. Comparison of these results, however, to the 

guidelines for the protection of fish-eating wildlife indicates 

that concentrations of the p,p’-DDT degradates and toxaphene 

continue to be of environmental concern. 

INTRODUCTION 

The Mississippi Embayment (MISE) study is one of more 

than 50 water-quality assessments that have been conducted as 

part of the U.S. Geological Survey’s National Water Quality Assessment (NAWQA) Program. The NAWQA Program 

seeks to improve scientific and public understanding of water 

quality in many of the Nation’s major river basins and groundwater systems. Collectively, these assessments cover about 

one-half of the land area of the United States and include 

water resources that are available to more than 60 percent of 

the U.S. population.

One of the major objectives of the NAWQA Program is 

to assess how the use of pesticides affects water quality, in 

both urban and agricultural settings. Coupe (2000) summarized the occurrence of almost 100 water-soluble pesticides in 

the surface waters of the MISE Study Unit. However, many 

organochlorine compounds generally are not present in water 

at concentrations large enough to be readily detectable with 

current technology, yet they can be detected in aquatic biota. 

Therefore, the NAWQA Program includes the assessments of 

28 selected organochlorine compounds in aquatic biota; these 

28 compounds include pesticides, pesticide degradates, and 

polychlorinated biphenyl (PCB) compounds. 

The organochlorine compounds in this study are anthropogenic chemicals that have been used to control many agricultural and urban pests. Although most of these older, more 

hydrophobic organochlorine pesticides are no longer available 

for use in the United States, they are manufactured for use in 

other nations, especially developing countries. Organochlorine 

pesticides were used in agricultural and urban settings for 

decades in the United States since the 1940s. The type and 

amount of organochlorine pesticide use has changed over the 

years as changes have occurred in crop type, technology, and 

regulations. Although the use of most of these organochlorine 

pesticides has been restricted in the United States, some of 

these pesticides or pesticides degradates are still frequently 

detected in the environment. For example, the sale, distribuConcentrations of Selected Organochlorine Compounds 

in Fish Tissue in the Mississippi Embayment Study Unit: 

Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and 

Tennessee, 1995-99

By Suzanne R. Femmer, Richard H. Coupe, Billy G. Justus, and Barbara A. Kleiss
tion, and use of dichlorodiphenyltrichloroethane (DDT) was 

discontinued in the United States in 1972 because DDT was 

suspected to cause thinning of eggshells in some fish-eating 

birds, such as cranes, herons, and eagles, resulting in dramatically decreased populations. However, 98 percent of fish 

samples from a nationwide study had detectable levels of DDT 

or one of its degradates (Schmitt and others, 1990) almost two 

decades after its sale was discontinued. Studies completed 

since the late 1970s indicated a widespread and pervasive 

contamination of all components of the ecosystem (air, soil, 

water, and biota) of DDT, its metabolites, and toxaphene in 

the Alluvial Plain part of the Yazoo River Basin (Cooper and 

others, 1987; Cooper, 1991; Coupe and others, 2000; Ford and 

Hill, 1991). Chlordane sales were discontinued in the United 

States in 1988, but chlordane is still readily detected in the 

environment (Haag and McPherson, 1997; Schmitt, 2002). 

PCBs are not pesticides, but they are used in a variety of 

industrial products. PCBs were manufactured in the United 

States from 1929 through 1979 and were used in the production of plastics, paints, adhesives, and as pesticide additives. 

PCBs are still in use as insulating and cooling liquids in electrical transformers and capacitors and, although the concentration of PCBs in fish tissue has been declining in National 

surveys, they are still frequently detected, especially in the 

industrialized parts of the country (Schmitt, 2002). 

The persistence of these organochlorine compounds in 

the environment and their propensity to accumulate in living 

tissue, coupled with the toxic effects of many of the organochlorine compounds, make them a source of continuing 

concern to the health of humans and biota (Wong and others, 

2000). Large concentrations of these compounds can cause 

mortality; at small concentrations, they can have an effect on 

humans and biota through processes such as cancer and reproductive disruption (Colburn and others, 1993). Some State and 

other Federal agencies have collected fish-tissue data within 

the MISE Study Unit; however, there has been no detailed 

study of fish tissue for the entire MISE Study Unit. 

Purpose and Scope 

This report describes the occurrence and distribution of 

28 organochlorine-pesticide, pesticide-degradate, and PCB 

concentrations in 64 whole fish-tissue samples collected from 

52 sampling sites in the MISE Study Unit (fig. 1) during1995-

99. The concentrations in fish tissue from the MISE Study 

Unit are compared to concentrations from other investigations in the United States, and compared to guidelines for the 

protection of fish-eating wildlife. The fish-tissue concentrations are also compared to characteristics of the watersheds in 

which the fish-tissue samples were collected.

Description of the Study Unit 

About 62 percent of the land use of the MISE Study Unit 

is agricultural, and some of the smaller drainage basins can be 

greater than 90 percent agricultural. About 33 percent of the 

MISE Study Unit is forested; most of these forested areas are 

near the eastern and western borders of the study unit. Most of 

the study unit is rural; the only major urban area in the study 

unit is Memphis, Tennessee, with a population of 650,100 

(U.S. Census Bureau, 2000). About 5 percent of the study unit 

is classified as urban or other land use. 

Most of the land area in the MISE Study Unit is comprised of two physiographic provinces; the Mississippi 

Alluvial Plain (MAP) and the Gulf Coastal Plains (GCP) 

(Fenneman, 1938). About 57 percent of the MISE Study Unit 

is comprised of the MAP physiographic province and is an 

area of little topographic relief. The soils of the MAP are 

dominated by clays and historically have supported extensive 

wetlands. These alluvial clays contribute to low permeability 

soils that limit rainfall infiltration and contribute to overland 

runoff rapidly entering the streams and waterways. About 

35 percent of the MISE Study Unit is comprised of the GCP 

physiographic province and abuts the eastern edge of the 

MAP; this part of the Study Unit is characterized by hills of 

wind-blown silts to the west and rolling to hilly topography 

with more permeable silts to the east. Soil permeability is 

greater in the GCP than in the MAP, which results in more 

surface runoff infiltrating the soil surface. The coarser soils on 

the steeper slopes of the GCP are more erodible than the soils 

in the MAP. 

The physiographic provinces (fig. 1) strongly correlate 

with ecoregions defined by Omernik (1987). The MAP Ecoregion overlaps the MAP physiographic province. Streams in the 

MAP Ecoregion have low gradients, and relief is sometimes 

less than 12.5 cm/km (Arkansas Department of Pollution 

Control and Ecology, 1987). About 75 percent (or about 6.5 

million hectares) of the original forested wetlands in the MAP 

Ecoregion have been cleared and drained (Nature Conservancy, 1992) and on average, more than 70 percent of the land 

in the MAP Ecoregion is used for growing row crops (primarily corn, cotton, and soybean) and small grains (primarily rice 

and wheat). The subtropical climate with long summers and 

plentiful rainfall results in the MAP having some of the most 

productive farmland in the world, but also increases the insect 

and weed pressure, which requires large amounts of pesticides 

for control. Because of this, pesticide use generally is higher 

in the MAP than in most other regions of the United States 

(Gianessi and Anderson, 1995). 

The GCP physiographic province includes the Mississippi Valley Loess Plains (MVLP) and the Southeastern Plains 

(SP) Ecoregions. The MVLP Ecoregion is a mosaic of forest 

and cropland, primarily irregular plains with oak-hickory and 

oak-hickory-pine natural vegetation. Streams in the MVLP 

Ecoregion tend to be incised, have low gradients, and silty 

substrates. The SP Ecoregion is a mixture of cropland, pasture, 

woodland, and forest. The natural vegetation is primarily oakhickory-pine and Southern mixed forests. Streams of the SP 

Ecoregion are relatively low gradient (except where modified 

by humans) with sandy substrates.

2 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
10

36 45

1

2

3

4

5

6

8 7

11 12

1413

15

19

20

21 22

23

25

26

27 29

28

30

32 31 33 34

40

41

42

37 35

38

17

1618

43

44

46

47

48

50

49

51

53

52

24

9

90°

89°

37°

91°

92° 36°

35°

34°

33°

32°

0 40 MILES

0 40 KILOMETERS

49

25

28

26

EXPLANATION

53

Ozark Highlands

Interior River Lowland

Mississippi Alluvial Plain

Mississippi Valley Loess Plains

Southeastern Plains

Boston Mountains

Arkansas Valley

South Central Plains

Study unit boundary

Mississippi Embayment Study Unit

sampling site

Ecoregions

Main Stem Mississippi River site

Inter-species comparison site

Site with duplicate samples

Site sampled multiple years

Mississippi

Alluvial Plain

Physiographic

Province

Gulf Coastal Plains

Physiographic

Province

KENTUCKY

MISSOURI

TENNESSEE

ARKANSAS

MISSISSIPPI

LOUISIANA

Source: Ecoregions - Omernik (1987);

Physiographic Province - Fenneman (1938)

Numbers refer to site numbers on table 1.

Figure 1. Physiographic provinces, ecoregions, and fish-tissue sampling sites of the Mississippi Embayment Study Unit.

Introduction 3
Geology of the MISE Study Unit (fig. 2) mostly consists 

of formations from the Tertiary and Quaternary periods (Warwick and others, 1997). The upper stratum comprises alluvial 

Pleistocene and Holocene units. Large rivers flowing through 

the area formed these units, carving the surface and depositing clay, silt, sand, and gravel to create the alluvium. During 

the last 2 million years, up to 300 feet of alluvium have filled 

this valley. The underlying Tertiary period formation comprises Pliocene, Eocene, and Paleocene units. These units are 

composed of layers of clay, glauconitic clay and sand, marl, 

and limestone.

Despite the relative flatness of the MAP, this area has a 

high sediment and water yield due to a combination of climatic factors and soil conditions. The erosive force of rainfall 

in the southeastern United States, including, the MISE Study 

Unit, is the highest east of the Rocky Mountains (Schmitt and 

Winger, 1980). The high silt and clay content of the alluvial 

plain soils in the Study Unit lowers the soil permeability, 

which increases runoff and erodibilty of these soils. Because 

of the past high useage of some organochlorine pesticides in 

cotton growing areas of the South (U.S. Environmental Protection Agency, 1975), coupled with their longevity and their 

propensity to adsorb to clay particles, there could be a constant 

supply of organochlorine pesticides to surface waters of the 

Study Unit as soils are eroded and move off agricultural fields. 

MATERIALS AND METHODS

Fish samples were collected at 52 (fig. 1, table 1) sites 

in the MISE Study Unit from 1995 though 1999. A total of 

64 fish-tissue samples, comprising 5-8 fish per sample, were 

sent to the National Water Quality Laboratory (NWQL) 

and homogenized. Tissue aliquots were then analyzed for 

28 organochlorine compounds. Protocols developed by the 

NAWQA Program were followed, and quality assurance 

methods were employed both in field collection and laboratory 

analysis. Statistical analysis was used to compare and contrast 

the data with various physical features of the study unit.

Sample Collection

Of the 64 fish-tissue samples, 17 were collected in 

1995, 18 were collected in 1996, 25 were collected in 1998, 

and 4 were collected in 1999 (table 2). Five of the 52 sites 

were sampled twice, in different years, to evaluate temporal 

variability; duplicate samples were collected at three sites to 

evaluate sampling variability; and three sites were sampled for 

different species to evaluate interspecies variability. Of the 52 

sites sampled, 47 are in the MAP Ecoregion, 4 sites are in the 

MVLP Ecoregion, and 1 site is in the SP Ecoregion. Of the 

47 sites in the MAP Ecoregion, 8 are on the main stem of the 

Mississippi River; all other sampling sites are on tributaries to 

the Mississippi River. Streams sampled ranged in size from 

wadeable streams (drainage basin of less than 100 km2

) to the 

main stem of the Mississippi River (drainage basin of almost 

3,000,000 km2). 

Fish were collected by electrofishing. Common carp 

(Cyprinus carpio) were targeted at all sites (Crawford and 

Luoma, 1993), but were not found in sufficient quantity at 

three sampling sites (table 3). At two of the three sites where 

carp were not collected, black bass (Micropterus spp.) were 

collected, and at the remaining site, spotted gar (Lepisosteus 

oculatus) were collected. Eight fish were targeted for each 

composite sample, but at some sites, fewer than eight fish were 

collected and composited into a sample (table 2). The weight, 

length, sex, and anomalies of each fish in each composite 

sample were recorded, and scales were collected for age determination. Each fish in the sample was wrapped in aluminum 

foil, placed in large plastic bags with other fish in the composite, and placed on dry ice and shipped directly to the NWQL 

in Denver, CO, or were returned to the U.S. Geological Survey 

(USGS) office on ice in Jackson, MS, where they were frozen 

and shipped to the NWQL at a later date.

Age Determination

Several scales were removed from each side of each fish 

from an area behind the pectoral fin and above the lateral 

line for the purpose of determining the age of the fish. Once 

removed, the scales were placed into small paper envelopes 

and allowed to dry. Prior to age determination, each scale 

was taped between two glass slides with clear, plastic tape. 

Age was determined by counting annuli by using an inverted 

microscope which projected an enlarged outline of the scale 

onto a projection screen. Methods for counting annuli are 

described by Carlander (1969) and by Summerfelt and Hall 

(1987). Ages were assigned as whole numbers (years). 

Sample Preparation and Analysis

Organochlorine pesticides, pesticide degradates, and 

PCBs in whole fish tissue were analyzed by the NWQL. 

Concentrations were reported as micrograms per kilogram wet 

weight. Analytical methods used by the NWQL for organochlorine pesticides and PCBs in whole fish tissue have been 

validated in several interlaboratory studies sponsored by the 

U.S. Fish and Wildlife Service and the U.S. Environmental 

Protection Agency, and are described in detail in Leiker and 

others (1995). In summary, whole fish were homogenized into 

a single composite by using a meat grinder. A 10-g sample 

aliquot was homogenized with 100 g of granular anhydrous 

sodium sulfate to remove residual water. After homogenization, two surrogates--alpha-HCH d6

 and 3,5-dichlorobiphenyl--were added to the sample, and the sample was Soxhlet 

extracted overnight in methylene chloride. The extract was 

then filtered through granular anhydrous sodium sulfate and 

concentrated to a volume of 5 mL. A 1.0-mL aliquot was 

removed for percent lipid determination. A 2.0-mL aliquot 

4 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
0 40 MILES

0 40 KILOMETERS

EXPLANATION

Holocene

Pleistocene

Tertiary and Older Formations

90°

89°

37°

KENTUCKY

MISSOURI

91°

92° 36°

TENNESSEE

35°

ARKANSAS

34°

MISSISSIPPI

33°

LOUISIANA

32°

Figure 2. Geologic age of surficial deposits of the Mississippi Embayment Study Unit.

Materials and Methods 5
of the extract was injected into an automated gel permeation 

chromatograph to isolate the analytes of interest from the lipid 

material that was coextracted. The extract was then solvent 

exchanged into hexane and further concentrated to a 1.0-mL 

volume. The extract was fractionated into two components 

by using alumina/silica adsorption chromatography: nonpolar 

organics such as PCBs, dichlorodiphenyldichloroethylene 

(DDE), hexachlorobenzene (HCB), heptachlor, aldrin, and 

3,5-dichlorobiphenyl surrogate; and polar organics such as 

chlordane, toxaphene, DDT, and DDD. The fractions were 

then concentrated to a 1.0-mL volume and analyzed by dual 

capillary column gas chromatography (GC) with electron 

capture detection (Leiker and others, 1995).

Compound identification was based on the GC retention 

times of both capillary columns compared to those obtained by 

use of external standard mixtures. The compound quantitation 

curve was based on the calibration curves of 5, 10, 20, 50, 100, 

and 200 pg/μL for chlorinated pesticides, 600 pg/μL for mixed 

aroclor standards for PCBs, and 800 pg/μL for toxaphene. 

The lower of the two observed concentrations from the two 

GC columns was reported except where recognized compound 

coelutions or interferences resulted in single-column quantification (Leiker and others, 1995).

Data Analysis

It is generally acknowledged that some physiological 

characteristics of fish such as age, sex, weight, length, species, lipid content, and metabolism, can have an effect on the 

concentration of hydrophobic compounds found in fish tissue. 

Many researchers normalize for one or more of these characteristics when evaluating concentrations in fish tissue. However, the relation between the physiological characteristics and 

fish-tissue concentration is not the same for every compound 

or every environmental condition, and it has been shown that, 

under some circumstances, normalizing data for lipid content 

may lead to misleading conclusions (Herbert and Keenleyside, 

1995). For example, Schmitt (2002) analyzed fish-tissue data 

collected in 1995 from the Mississippi River Basin, including 

some sites in the MISE Study Unit, and attempted to correlate 

p,p’-DDT, the sum of the cyclodiene pesticides, and PCBs 

with length, weight, and age. The only significant correlation 

with p,p’-DDT was a negative correlation with age for male 

and female carp. For the cyclodiene pesticides, concentrations in male and female bass were negatively correlated with 

length, and concentrations in female bass were negatively correlated with weight. However, both female and male carp had 

positive correlations between length and weight with concentrations of PCBs in tissue. Therefore, a single normalization 

method was not possible, and Schimtt (2002) chose not to 

normalize the data when analyzing the data geographically. 

Differences in the concentration of hydrophobic compounds, which may vary considerably in source strength, 

could obscure any relation between concentration and physiological characteristics. Unless it is clear that the source is 

similar across a geographic area, normalizing may add, rather 

than decrease variability in the data. 

Additionally, because the samples collected by the MISE 

NAWQA were composites of up to eight fish, with mixed 

gender, an average value of lipid content, weight, or age would 

have to be used, and thus, normalizing becomes problematic. Therefore, the data presented here are not normalized, 

although the percent lipids of the composite sample, the average weight, average total length, and average age of the fish, 

whenever available, are listed in table 3. 

The sampling sites were subdivided into classes based 

on ancillary data (such as drainage basin size, bed sediment 

particle size, and soil type) and the Kruskal-Wallis test was 

used to determine if there were differences in the median 

organochlorine concentration between classes (Helsel and 

Hirsch, 1992). The main stem Mississippi River samples were 

not used in this analysis. An alpha value of 0.05 was used to 

evaluate the significance of the test results. The classes are 

significantly different if the probability (p-value) is less than 

the alpha value. A p-value of less than 0.05 indicates that 

there is a less than 5 percent chance that the observed difference was by chance. If a significant difference was detected, 

these differences were further analyzed by applying Tukey’s 

multiple comparison test (Helsel and Hirsch, 1992,) to the 

rank transformed data. Ancillary data with less than three 

classes were not analyzed by using Tukey’s test. If significant 

differences were found, the data were graphically displayed 

by using boxplots. Classes with 10 or less values are nonideal 

for confident statistical testing and the results should be used 

with caution. For analysis, concentrations below the method 

reporting limit (MRL) were represented by a value of one-half 

the MRL. Total DDT (TDDT) concentrations were calculated 

as the sum of o,p’–DDT and p,p’–DDT and their degradates; 

for this report the concentrations were set to 0 if they were 

reported as less than the MRL.

Reporting Limits and Quality-Control Procedures 

Surrogate compounds were added to the homogenized 

tissue samples in order to measure the overall method efficiency. These surrogate compounds were not expected to be 

present in the environment, yet were expected to behave similarly to selected target analytes found in the environment. This 

method calls for the addition of two surrogate compounds: 

an organochlorine compound (alpha-HCH-d6) and a PCB, 

3, 5-dichlorobiphenyl. These surrogates were used to assess 

the recoveries for the targeted analytes. The median overall recoveries for these compounds were 93 and 81 percent, 

respectively (fig. 3). More than 95 percent of the recovery data 

fell within the expected range of 3 sigma and, therefore, were 

within analytical control (Leiker and others, 1995).

Generally, the compounds analyzed for in fish tissue in 

this study (table 2) had a MRL of 5.0 μg/kg, with the exception of toxaphene (MRL of 200 μg/kg) and PCB (MRL of 

50 μg/kg). Occasionally, the MRL for some compounds was 

6 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
concentration in the fish population. In order to assess this 

assumption, duplicate samples were collected and samples 

were collected at the same site during different years to assess 

year-to-year variability. At a few sites the target species (carp) 

was not available and a substitute species (bass or gar) was 

used to measure organochlorine concentrations in fish tissue. 

To assess interspecies variability, samples of bass or gar were 

collected and analyzed concurrently with the carp samples at 

four sites (two for bass and two for gar). 

Duplicate samples were collected at three sites during 

1995-99 and represent approximately 5 percent of all samples 

collected for the fish-tissue study. These duplicate samples 

are used to evaluate the variability in sampling and the variability due to the analytical methods. At the sampling site, a 

duplicate sample was processed similarly to the environmental 

sample and was sent to the NWQL for analysis. An analysis 

of variance was run on the age, weight, and total length of the 

individual fish between duplicate samples, and there were no 

significant differences indicating that the targeted sampling 

was successful. 

In November 1996, duplicate samples were collected at 

the Mississippi River sites at River Mile 432 (map number 52 

and samples 61 and 62, table 2) and at River Mile 475 (map 

number 47 and samples 55 and 56, table 2). Most compounds 

were reported below the MRL for both sets of samples. Seven 

compounds were reported at concentrations above the MRL in 

both samples at River Mile 432: PCBs (740 and 720 μg/kg), 

trans-nonachlor (16.0 and 10.0 μg/kg), dieldrin (30.0 and 

23.0 μg/kg), p,p’-DDE (170 and 160 μg/kg), p,p’-DDD (19.0 

and 14.0 μg/kg), trans-chlordane (9.5 and 7.3 μg/kg), and 

cis-chlordane (12.0 and 8.7 μg/kg). Hexachlorobenzene was 

reported slightly above the MRL in one sample and below the 

MRL in the other. Four compounds were reported above the 

MRL in samples from the Mississippi at River Mile 475: PCB 

(200 and 530 μg/kg); dieldrin (15.0 and 23.0 μg/kg); p,p’-

DDE, (140 and 120 μg/kg) and p,p’-DDD (8.4 and 8.8 μg/kg). 

Hexachlorobenzene was reported slightly above the MRL in 

one sample and was not detected in the other; cis-chlordane 

and trans-nonachlor were reported with an estimated concentration below the MRL in one sample and were undetected in 

the other sample.

A duplicate sample was collected in June 1999 at the 

Steele Bayou (weir E) at the Yazoo National Wildlife Refuge, 

Miss. (map number 53 and samples 63 and 64, table 2). There 

were five compounds detected in both samples at concentrations above the MRL: PCB (52.0 and 140 μg/kg), dieldrin 

(15.0 and 24.0 μg/kg), p,p’-DDE (2,300 and 1,500 μg/kg), 

p,p’-DDD (430 and 340 μg/kg), and p,p’-DDT (45 and 70 

μg/kg). Two compounds were reported above the MRL in one 

sample and below the MRL in the other: trans-nonachlor (<8.8 

and 11.0 μg/kg), and cis-chlordane (<5.2 and 8.3 μg/kg).

 Only 8 of the 28 compounds analyzed for were reported 

at levels above the MRL in both samples in one or more of the 

three duplicates. Therefore, for the other 20 compounds not 

detected in the duplicate samples, no conclusions, other than 

there was no contamination of the fish tissue from external 

Materials and Methods 7

1

 The BEST program (Biomonitoring of Environmental Status and Trends) incorporated the NCPB sampling sites and responsibility for the program was 

changed from the Fish and Wildlife Service to the National Biological Survey/Service, which became the Biological Resources Division of the U.S. Geological 

Survey (Schmitt and others, 1999).

25

50

75

100

125

150

175

200

RECOVERY IN PERCENT

3,5-DICHLOROBIPHENYL ALPHAHEXACHLOROCYCLOHEXANE D6

Figure 3. Surrogate recoveries for samples analyzed by the 

National Water-Quality Laboratory, 1995-99.

higher than shown above, possibly because of matrix interference, instrument problems, or coeluting constituents. There are 

several reasons a value might be reported as estimated, such 

as a confirmed value above or below calibration standards, 

or poor method performance. These estimated values were 

considered valid data and were used in this report. 

In 1995, as part of a quality assurance program with the 

National Contaminant Biomonitoring Program (NCBP)1

, fish 

samples from eight sites (map numbers 2, 11, 17, 19, 28, 32, 

33, and 36) were collected for both the NCBP and NAWQA 

programs and sent to their respective laboratories. NAWQA 

field personnel collected the fish samples, but NCBP protocols 

were followed for NCBP samples, and NAWQA protocols 

(which differed slightly from NCPB protocols) were followed 

for NAWQA samples. Details on the field and laboratory 

methods used by the NCBP can be found in Schmitt (2002). 

Results for constituents that are common between the two 

programs are shown in table 4. In general, data from the two 

programs compare favorably. Concentrations reported by 

NCBP and NAWQA programs are usually within the same 

order of magnitude, and if a constituent was detected by one 

laboratory, the other usually detected it. The exceptions are 

the concentrations of p,p’-DDT and o,p’-DDT. Concentrations of p,p’-DDT ranged from 36 to 140 μg/kg from 6 of the 

9 samples analyzed by the NWQL, but were reported as <10 

μg/kg for the NCBP samples. Two samples analyzed by the 

NWQL had reportable concentrations of o,p’-DDT (35 and 56 

μg/kg), whereas, there were no concentrations of o,p’-DDT 

above the MRL from NCBP data. 

Field Quality Assurance

The analyses in this report on the relations between the 

concentration of organochlorine compounds in fish tissue and 

landscape variables are predicated on the assumption that the 

samples used to measure the concentrations of organochlorine compounds in fish tissue are representative of the true 
sources, can be made. The average relative percent difference 

(RPD = |A-B|/[[A+B]/2]) • 100 for duplicate samples ranged 

from 21 percent for p,p’-DDE to almost 62 percent for PCB 

(table 5); however, the relative magnitude for most compounds 

was the same, and the presence of these compounds was confirmed in both samples. Some compounds were reported above 

the MRL in one sample and not in the other; but in every 

instance, the concentration reported was near the MRL.

 In order to assess temporal variability in organochlorine 

concentrations in fish tissue, samples were collected over 

multiple years at five sites in the MISE Study Unit: the Yazoo 

River (map number 35 and sample numbers 42 and 43, table 

2), Tensas River (map number 36 and sample numbers 44 

and 45, table 2), Cassidy Bayou (map number 24 and sample 

numbers 26 and 27, table 2), Quiver River (map number 26 

and sample numbers 29 and 30, table 2), and the Bogue Phalia 

(map number 28 and sample number 32 and 34, table 2). The 

analysis of variance results by sampling sites for fish weight, 

age, and total length between sampling years are listed in 

table 6. 

Cassidy Bayou (map number 24) was sampled in October 

1995 and in June 1998; concentrations of seven compounds 

were reported above the MRL in at least one of the samples. 

Three of these compounds (PCB, dieldrin, and p,p’-DDT) had 

higher concentrations in the 1998 sample and four compounds 

(toxaphene, p,p’-DDE, o,p’-DDD and p,p’-DDD) had lower 

concentrations in the 1999 sample. 

The Quiver River (map number 26) was sampled in July 

1996 and in June 1998. Of the organochlorine compounds 

that were present in concentrations above the MRL in the 

July 1996 sample, all had higher concentrations in the 1998 

sample. This can be partially explained by an almost three-fold 

increase in percent lipids (3.2 – 9.1 percent) between sampling 

years.

Bogue Phalia (map number 28) was sampled for organochlorine compounds in fish tissue in August 1995 and in 

August 1999. All of the compounds that were detected above 

the MRL in 1995 (PCBs, toxaphene, mirex, dieldrin, and the 

degradates of p,p’-DDT and o,p’-DDT) had lower concentrations in 1999.

The Yazoo River (map number 35) was sampled in 

September 1995 and in December 1996. Most compounds that 

were detected in 1995 above the MRL had lower concentrations in 1996. The concentration of PCBs in fish tissue was 

unchanged from the 1995 sample to the 1996 sample, and 

mirex was the only constituent to increase in concentration 

from 1995 to 1996. Toxaphene concentrations decreased from 

1,600 μg/kg to below the MRL of 200 μg/kg. Concentrations 

of DDT and its degradates, and the chlordane degradates were 

lower in 1996 than in 1995.

 The Tensas River (map number 36) was sampled in 

August 1995 and in September 1999. Most organochlorine 

compounds detected in August 1995 were present in lower 

concentrations in 1999. However, concentrations of, o,p’ and 

p,p’-DDT and o,p’-DDD were higher in 1999. Toxaphene, 

o,p’-DDE, and p,p’-DDD concentrations were lower by one 

order of magnitude in 1999 than in 1995. The concentrations 

of p,p’-DDE decreased from 5,300 to 2,500 μg/kg from 1995 

to 1999.

One of the methods for putting the multi-year data into 

perspective is to examine how the variability in the multiyear sampling compares with the variability in the duplicate 

samples. The variability in the duplicate samples should represent the variability due to sampling and analytical methods 

as well as the natural variability of the system. The RPD for 

those constituents reported above the MRL, percent lipids in 

the duplicate samples, and the RPD and percent lipids for the 

same constituents in the multi-year sampling are listed in 

table 5. These data indicated that there was substantially 

increased variability (with the exception of PCB concentrations) in the multi-year sampling over that of the duplicate 

samples. This variability did not appear to be linked to the 

length of time between samples nor to a change in the percent 

lipids as the mean percent lipids for the duplicate samples 

were similar to the mean percent lipids for the multi-year samples. The multi-year samples with the most difference between 

samples (Quiver River) were sampled only 2 years apart, and 

some of the other sites, which were sampled 4 years apart, 

showed little difference. The number of multi-year samples 

is too few to make generalized statements about the trends in 

the fate of organochlorine compounds in the MISE Study Unit 

over time, but the implications of these samples (that there can 

be substantial variability between mutli-year samples) needs to 

be understood when examining the data.

Bass (3 sites) and gar (1 site) were used instead of carp 

at a few sites because carp were unavailable in sufficient 

quantity. In order to understand the interspecies variability in 

organochlorine and PCB concentrations, carp and bass were 

collected and analyzed at one site (map number 15, samples 

16 and 17, table 2) and carp and gar were collected and analyzed at two sites (map number 28, samples 32 and 33; map 

number 35, samples 41 and 42, table 2). These data indicate 

that carp may be slightly more susceptible to organochlorine 

compound contamination. However, the occurrence and relative magnitude of organochlorine compounds in carp seem to 

have been reasonably reflected in bass and gar, and the data 

are comparable for the purposes in this report. 

RESULTS AND DISCUSSION

There were many organochlorine compounds detected 

in fish-tissue samples of the Mississippi Embayment study. A 

statistical summary of the 28 organochlorine compounds for 

all samples is listed in table 7. Including duplicate and multiyear samples, 64 samples were available for analysis. The 

percentage of detections ranged from 0 to 100 percent. Aldrin, 

p,p’-methoxychlor, o,p’-methoxychlor, lindane, alpha-HCH, 

heptachlorepoxide, and endrin were not detected at concentrations above the MRL in any of the 64 samples. However, it 

is worthy of note that aldrin quickly degrades to dieldrin and 

8 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
dieldrin was detected in many samples (Nowell and others, 

1999). A degradate of DDT, p,p’-DDE, was detected in every 

sample. Another degradate of DDT, p,p’-DDD was detected in 

94 percent of the samples. PCBs were detected in 83 percent 

of the samples, and dieldrin was detected in 78 percent of the 

fish-tissue samples.

Nowell (1999) compiled a dataset of organochlorine 

compounds in fish tissue from data collected (1992-95) from 

273 sites nationwide in 20 NAWQA Study Units. Although 

this dataset was not a statistical representation of organochlorine compounds in fish tissue throughout the United States, it 

did represent the most recent and complete dataset available 

and facilitates comparison of MISE NAWQA data to that from 

other areas of the United States. The maximum measured 

concentrations for eight compounds (toxaphene, cis-nonachlor, 

mirex, delta-HCH, beta-HCH, p,p’-DDD, p,p’-DDE, and 

p,p’-DDT) were higher from sites in the MISE NAWQA than 

from any other site in the national dataset; other compounds, 

not as closely linked to row crop agriculture, such as PCBs 

and chlordane, had much higher maximum concentrations in 

the national dataset. In contrast, only two organochlorine compounds (p,p’-DDE, and toxaphene) from the MISE NAWQA 

data had maximums greater than 1984 data collected by the 

NCBP from 112 stations nationwide (Schmitt and others, 

1990). The maximum concentrations for p,p’-DDT and toxaphene in the NCBP 1984 data were from samples collected 

from the Yazoo River. Comparing the MISE NAWQA data 

with the national dataset and with the 1984 NCBP data indicated that fish-tissue samples from streams in the MISE Study 

Unit had some of the highest concentrations of organochlorine 

compounds in the country. 

One to fifteen (4 to 54 percent) of the organochlorine 

compounds were detected in every whole fish-tissue sample 

collected in the Mississippi Embayment Study Unit (fig. 4). 

The maximum number of organochlorine compounds in fish 

tissue in this study was collected in 1995; 15 of 28 (54 percent) of the organochlorine compounds were detected in the 

fish tissue from the Tensas River at Tendal, La., although a fish 

sample collected in 1999 from the Tensas River had 11 of 28 

(39 percent) organochlorine compounds detected. The minimum number of organochlorine detections was from LaGrue 

Bayou near DeWitt, Ark., in 1996, where only one compound 

was detected ( p,p’-DDE). The sites with the greatest percentage of detections of organochlorine compounds were generally 

located in the southern part of the study area (fig. 4). 

Samples were collected from eight sites on the main 

stem of the Mississippi River. Three to 9 (11 to 29 percent) 

of the organochlorine compounds were detected in fish tissue 

at these sites. The compounds reported and the magnitude of 

those concentrations in whole fish were similar among the 

Mississippi River sites. Every sample from the Mississippi 

River had detectable concentrations of PCBs, dieldrin, and 

p,p’-DDE; none had reported concentrations above the MRL 

of toxaphene. Most other compounds that were detected in fish 

samples from the Mississippi River were only detected at a 

few sites and were at concentratons near the MRL.

 DDT 

Detection of DDT in fish tissue was widespread throughout the MISE study area as evidenced by DDT and/or one 

of its degradates being reported in all 64 fish-tissue samples 

collected in the MISE Study Unit during 1995–99. This was 

an expected result given the long half-life of DDT, and the fact 

that about 80 percent of the domestic use of DDT (prior to its 

use being discontinued) was on cotton (U.S. Environmental 

Protection Agency, 1975), and that cotton was historically a 

major crop in the study unit. All samples had concentrations 

of p,p’-DDE above the MRL; 94 percent had p,p’-DDD, 52 

percent had p,p’-DDT, 34 percent had o,p’-DDD, 17 percent 

had o,p’-DDE, and 9 percent had o,p’-DDT concentrations 

above the MRL.

TDDT values ranged from 30 μg/kg (Spillway Ditch, map 

number 3, sample 3, table 8) to 9,494 μg/kg (Cassidy Bayou, 

map number 24, sample 26, table 8) and had a median value of 

584.5 μg/kg. The national median of DDT and its degradates 

in fish tissue has decreased throughout recent years as indicated by several national surveys (Nowell and others, 1999). 

The NCBP found decreasing median concentrations, ranging 

from 430 to 750 μg/kg during the years 1965–72, 180 to 335 

μg/kg during 1972–75, 220 μg/kg during 1976–77, and 90 to 

120 μg/kg during 1984–86. The median total DDT concentration of the 1995–99 MISE fish-tissue samples is about 584 

μg/kg, substantially above the national median values, except 

for the first set of data, 1965-72, when DDT was in active use 

in the United States. 

It has been suggested that unexpectedly high ratios of 

DDT concentrations to TDDT concentrations can be used as 

an indicator of recent use of DDT (Aguilar, 1984); however, 

that is not always the case, as high ratios of DDT/TDDT can 

also indicate movement of contaminated soil into streams 

(Nowell and others, 1999, p. 343-345). The highest DDT/

TDDT ratio found in this study was 12 percent, and most other 

ratios were below 10 percent. Schmitt and others (1990) suggest that a change in the proportional composition of the DDT 

mixture in fish tissue from about 70 percent p,p’-DDE to 73 

percent p,p’-DDE indicated a continued weathering of DDT 

in the environment across the United States. The mean percent 

p,p’-DDE concentration in this study was almost 83 percent. 

These data do not indicate recent use of DDT or large inputs 

of contaminated sediments to most streams that were sampled 

as part of this study, but rather a widespread and pervasive 

contamination of the environment with DDT from historical 

use.

 Relation with Ancillary Data

Ancillary data such as geology, physiographic region, 

drainage basin size, land use (basin and buffer zone), bedResults and Discussion 9
2

11

19

24

25

28

32

33

35 36

37

41

42

17

40

89°

90°

37°

36°

35°

34°

33°

32°

91°

92°

1995

Detections

Nondections

10

14

21

26

30

35

18

89°

90°

37°

36°

35°

34°

33°

32°

91°

92°

1996

46

48 47

49

50

51

52

30

26

18

43

10

21

44

45

1

3

4

5

6

8 7

9 10 12

1413

15

20

22

23

24

26

27 29

31 34

38

16

89°

90°

37°

36°

35°

34°

33°

32°

91°

92°

1998

38

23

20

22

34 31

29

27

26

16

15

9

8

12

14

13

3

7

1

4

10

6

5

28

36

89°

90°

37°

36°

35°

34°

33°

32°

91°

92°

0

0

40

40

MILES

KILOMETERS

1999

53

EXPLANATION

28 Map number

0

0

40

40

MILES

KILOMETERS

0

0

40

40

MILES

KILOMETERS

0

0

40

40

MILES

KILOMETERS

Figure 4. Percent detections of 28 organochlorine compounds in whole fish from 52 sampling sites in the Mississippi Embayment Study 

Unit, 1995-99.

10 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
sediment particle size, and permeability (table 1) were collected and collated for each drainage basin. The Mississippi 

River sites were not included in this analysis because of the 

large influence on water quality of the Mississippi River from 

upstream sources not within the MISE Study Unit. The fish 

tissue data were classed according to basin characteristics and 

statistically analyzed for differences among classes. These 

results should be used with caution as they do not imply 

cause and effect and could be the result of other factors not 

accounted for in these analyses.

Agricultural land use dominates the study area and 

overshadows the other land uses in statistical analysis. The 

dominant drainage-basin land use was arbitrarily divided into 

two classes, agricultural (greater than or equal to 55 percent 

agricultural land use) and nonagricultural (less than 55 percent 

agricultural land use). This division resulted in the nonagricultural class to have four values which was considered 

nonideal for analysis. The Kruskal-Wallis test on this nonideal 

dataset resulted in no significant differences between the two 

groups. The dominant buffer zone (area within 60 meters of 

the stream) land-use data were also divided into two classes, 

agricultural (greater than or equal to 55 percent agricultural 

land use in the buffer zone) and mixed (less than 55 percent 

agricultural land use in the buffer zone). This classification 

resulted in 37 sites in the agricultural class, and 10 sites in the 

mixed land-use class. Kruskal-Wallis analysis identified no 

statistically significant differences between organochlorine 

concentrations and dominant buffer zone land-use classes.

The sampling sites were divided in two classes based 

on drainage basin size, large (greater than 1,310 km2

) and 

small (less than 1,310 km2). This designation resulted in the 

large class with 21 samples and the small basin class with 30 

samples. Analysis by Kruskal-Wallis indicated that PCB concentrations were significantly different between classes 

(p-value of 0.026). The median PCB concentrations were 100 

μg/kg for the large basin class and 64.5 μg/kg for the small 

basin class (fig. 5). One possible explanation for the larger 

PCB concentrations in larger drainage basins is that there 

is more probability of including urban areas in the larger 

basins and the presence of PCBs has been shown to be related 

strongly to population density and urban areas (Murray and 

others, 2003).

The dominant geology of the study area consisted of 

the Tertiary system, and the Pleistocene and Holocene series. 

Fish-tissue samples in this discussion are described as being 

in a class named for the geology of the associated deposits. 

Analyzing the organochlorine data by geologic characteristics 

resulted in 5 samples in the Tertiary system class, 19 samples 

in the Pleistocene class, 15 samples in the Holocene class, and 

8 samples in the mixed geology class. The Tertiary system 

class had too few samples for ideal statistical analysis. Analysis by Kruskal-Wallis test indicated that there are significant 

DRAINAGE CLASS

PCB’s IN MICROGRAMS PER KILOGRAM

Large Basin

(greater than 1,310 km )2

Small Basin

(less than 1,310 km )2

0

100

200

300

400

A

B

IQR

Last value within

+1.5 * IQR

75th percentile

Q(75)

Median

Q(50)

25th percentile

Q(25)

Last value within

-1.5 * IQR2

Value greater than

1.5 * IQR

Quartile

Interquartile range

Q

IQR

EXPLANATION

(17) Number of samples

(17)

(21)

(30)

Figure 5. PCB concentrations in whole fish from large (greater than 1,310 km2) and small (less than 1,310 km2) drainage basins in the 

Mississippi Embayment Study Unit, 1995-99.

Results and Discussion 11
differences in organochlorine concentrations by geology class 

for the following compounds: toxaphene (p= 0.000), dieldrin 

(p=0.025), p,p’-DDE (p=0.000), o,p’-DDD (p=0.003), 

p,p’-DDD (p=0.000), and p,p’-DDT (p=0.000). Further analysis by Tukey’s method indicated that toxaphene, p,p’-DDE, 

and p,p’-DDD concentrations were significantly different 

between geology classes and that concentrations were higher 

in streams located in the Holocene geology than mixed geology, followed by Pleistocene geology (fig. 6). Concentrations 

of p,p’-DDT were significantly higher from the mixed geology, followed by the Holocene and then Pleistocene geology. For dieldrin and o,p’-DDD, the concentrations were not 

significantly different between streams in Holocene or mixed 

geology, but they were higher and significantly different than 

streams in Pleistocene geology. 

Average soil permeability at sites in the study unit ranged 

from 1 to 22 cm/hr with a median value of 2.6 cm/hr. These 

values were divided into three classes, high (3.2 to 22 cm/hr), 

moderate (1.9 to 3.2 cm/hr), and low (1 to 1.9 cm/hr). There 

were 12 samples in the high permeability class, 21 samples 

in the medium permeability class, and 14 samples in the low 

permeability class. Kruskal-Wallis testing on organochlorine 

compounds and the permeability classes indicated significant differences between classes for toxaphene (p=0.002), 

mirex (p=0.028), p,p’-DDE (p=0.000), o,p’-DDD (p=0.001), 

p,p’-DDD (p=0.004), p,p’-DDT (p=0.007), and o,p’-DDT 

(p=0.024). Further analyses by Tukey’s method show that, in 

general, the highest concentrations for the above compounds 

were found in fish tissue from streams in basins with soils of 

low permeability (fig. 7).

Particle size designations for streambed material were 

developed for each site sampled. The percentages of clays, silt, 

and sand were determined for each site. From these percentages, the sites were categorized by dominant (greater than 

55 percent) particle size. If there was not a dominant particle 

size at a site, the site was designated as a mixed particle size 

site. Partitioning these sites into dominant particle size classes 

resulted in the following class sample sizes: clay, 5; silt, 8; 

sand, 29; and mixed, 5. Although the small size of clay, silt, 

and mixed classes are nonideal for statistical analysis, Kruskal-Wallis testing indicated significant differences between 

particle size categories for PCB (p=0.002), toxaphene 

(p=0.010), dieldrin (p=0.007), p,p’-DDE (p=0.015), o,p’-DDE 

(p=0.029), o,p’-DDD (p=0.025), p,p’-DDD (p=0.004), transchlordane (p=0.002), and cis-chlordane (p=0.000). Analyzing the data by Tukey’s method showed that the sites with 

the smaller particles sizes, (clay or, in some cases, silt) as the 

dominant particle size had significantly higher concentrations 

compared to the other sites with larger particle sizes (fig. 8). 

Bed-sediment particle size and the soil permeability of 

the drainage basin probably are related as the streambed material is made up of material from the soil of the drainage basin. 

There can be some sorting of particle sizes in streams, as the 

larger particles will settle out according to the velocity of the 

stream. One explanation for the higher concentrations of some 

organochlorine compounds in basins with low soil permeability and/or smaller particle sizes is that the clay type particles 

have larger surface areas, which may weakly adsorb some of 

these hydrophobic compounds. These clay particles can then 

be transported into streams by runoff or wind erosion, and the 

organochlorine compounds may desorb from the clay particles 

due to equilibrium partitioning or the clay might be ingested 

by benthic organisms and the organochlorine compounds 

move into the food chain in this manner. 

Comparison with National Standards and 

Guidelines

The standards for organochlorine compounds in fish tissue 

that are written for the protection of human health refer to the 

edible portion of the fish and are not directly comparable to the 

results in this report. There are, however, guidelines for some 

organic compounds in whole-fish tissue for the protection of 

fish-eating wildlife (National Academy of Sciences and National 

Academy of Engineering, 1973; Nowell and Resek, 1994; table 

7). Comparing the MISE fish data with these standards can help 

identify areas of concern and for further study. There are no suggested standards and guidelines for pentachloroanisole, hexachlorobenzene, and dacthal concentrations for the protection of 

fish-eating wildlife.

Aldrin, endrin, lindane, and methoxychlor had maximum 

concentrations less than the MRL of 5 μg/kg, and therefore, do 

not appear to be a significant concern for fish-eating wildlife 

in the MISE Study Unit (table 7). Concentrations of PCBs and 

chlordane exceeded the National Academy of Sciences and 

National Academy of Engineering (NAS/NAE) guidelines in a 

few samples; none of the dieldrin concentrations exceeded the 

guidelines. Concentrations of TDDT and toxaphene exceeded the 

NAS/NAE guidelines in more than 25 percent of the fish-tissue 

samples collected in the MISE Study Unit. Almost two-thirds of 

the TDDT samples exceeded the New York Fish Flesh Criteria 

(NYFF). Because of the difficulty in analyzing for toxaphene, the 

usual MRL for toxaphene is quite high (200 μg/kg), compared 

to the MRL for the other organochlorine compounds. Many fishtissue samples had a much higher MRL for toxaphene (400 to 

1,100 μg/kg). Two hundred micrograms per kilogram is double 

the NAS/NAE guideline (100 μg/kg). Given the distribution of the 

concentration of toxaphene in fish-tissue samples shown in table 

7, it is possible that more than 50 percent of the fish-tissue samples exceeded the guidelines of 100 μg/kg. These data indicate 

that of the compounds that have NAS/NAE or NYFF guidelines, 

only TDDT and toxaphene exceeded the guidelines frequently 

and could be a concern in the MISE Study Unit, especially the 

southern part of the study unit. Schmitt (2002) also concluded 

from 1995 NCBP data that concentrations of TDDT (primarily 

as p,p’-DDE) were great enough in the cotton farming regions of 

the lower Mississippi River Basin (primarily the MISE Study 

Unit) to constitute a hazard to fish-eating wildlife.

12 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Results and Discussion 13

Figure 6. Selected organochlorine concentrations in whole fish collected from sampling sites in which the surficial soils of the drainage 

basin are primarily of the Holocene, Pleistocene, or mixed geologic age in the Mississippi Embayment Study Unit, 1995-99.

(15) (15) 12,000

10,000 60

oxaphene

8,000

40 6,000 (8) Dieldrin

(19)

(8)

T

4,000 20 A A

2,000 (19)

B A B C

KILOGRAM

0 0

HMP HMP

(15) (15) (8)

PER

120

MICROGRAMS

6,000 (8)

DDD

DDE

4,000

A

o,p’-

80 -

(19)

p,p’

2,000 B 40 A

IN

(19)

TIONS

A 0 C 0 B

CONCENTRA

HMP HMP

(15) 2,000 (8)

500

1,500 400

-DDD

(15)

300 1,000 (8) -DDT

p,p’

p,p’

200 A

500 B

(19) 100 (19)

A B 0 C 0 C

HM P HMP

EXPLANATION Q Quartile

IQR Interquartile range

Boxes with the same (17) Number of samples

letter are not significantly Value greater than

different ( <=0.05) 1.5 * IQR

Geologic age Last value within (17) +1.5 * IQR

H Holocene

M Mixed 75th percentile

Q(75)

P Pleistocene Median IQR Q(50)

25th percentile

Q(25)

Last value within

-1.5 * IQR2
Figure 7. Selected organochlorine concentrations between classes of soil permeability, in the Mississippi Embayment Study Unit, 1995-99.

14 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99

H

0

2,000

4,000

6,000

8,000

10,000

12,000

Toxaphene

H

0

20

40

60

80

100

Mirex

H

0

2,000

4,000

6,000

p,p’-DDE

H

0

500

1,000

1,500

2,000

p,p’-DDD

H

0

40

80

120

o,p’-DDD

H

0

100

200

300

400

500

p,p’-DDT

H

0

10

20

30

40

50

o,p’-DDT

(12)

(12)

(12) (12)

(12)

(12)

L

L

L

L

(14)

(14)

(14)

(14)

A

A

A

A A

B

B

B C

C

C

(11)

M

M

M

M

(21)

(21)

(21)

(21)

A

B

B

B

L

L

L

(14)

(14)

(14)

A

A

A

M

M

M

(21)

(21)

(21)

A

A

CONCENTRATIONS IN MICROGRAMS PER KILOGRAM

B

IQR

Last value within

+1.5 * IQR

75th percentile

Q(75)

Median

Q(50)

25th percentile

Q(25)

Last value within

-1.5 * IQR2

Value greater than

1.5 * IQR

Quartile

Interquartile range

Q

IQR

(17) Number of samples

(17)

Boxes with the same

letter are not significantly

different ( <=0.05)

EXPLANATION

H

Soil permeability class

M

L

High permeability (greater

than or equal to 3.2

centimeters per hour)

Moderate permeability

(less than 3.2 and greater

than 1.9 centimeters per

hour)

Low permeability (less

than or equal to 1.9

centimeters per hour)
Figure 8. Selected organochlorine concentrations between bed-sediment particle size, in the Mississippi Embayment Study Unit, 1995-99

Results and Discussion 15

CL M SA SL

0

100

200

300

400

PCB

CL M SA SL

0

2,000

4,000

6,000

8,000

10,000

12,000

Toxaphene

CL M SA SL

0

20

40

60

Dieldrin

CL M SA SL

0

2,000

4,000

6,000

p,p’-DDE

CL M SA SL

0

20

40

60

o,p’-DDE

CL M SA SL

0

40

80

120

o,p’-DDD

CL M SA SL

0

500

1,000

1,500

2,000

p,p’-DDD

CL M SA SL

0

5

10

15

20

Cis-chlordane

CL M SA SL 0

5

10

15

20

Trans-chlordane

(5)

(29) (29)

(29)

(29)

(29)

(29)

(29)

(29)

(8)

(8)

(8)

(8)

(8)

(8)

(8)

(8)

(5)

(5)

(5) (5)

(5)

(5)

(5) (5)

(5)

(5)

(5) (5)

(5)

(5)

(5)

A

A

A

A

A

B B B

B B

B B

B

B B B

C C

C C

A

B

B B

A

C

C

B

A B B

A A

B B

A

(29)

(8)

(5)

(5)

CONCENTRATIONS IN MICROGRAMS PER KILOGRAM

IQR

Last value within

+1.5 * IQR

75th percentile

Q(75)

Median

Q(50)

25th percentile

Q(25)

Last value within

-1.5 * IQR2

Value greater than

1.5 * IQR

Quartile

Interquartile range

Q

IQR

(17) Number of samples

(17)

Boxes with the same

letter are not significantly

different ( <=0.05)

EXPLANATION

CL

Particle size

M

SA

Clay

Mixed

Sand

SL Silt
SUMMARY AND CONCLUSIONS

The Mississippi Embayment Study Unit is located in one 

of the most agriculturally intensive areas of the United States 

and, although the use of many organochlorine pesticides and 

PCBs has been discontinued in the United States, there is 

concern over their environmental fate, especially in the cotton 

growing areas of the southeastern United States where historical use of organochlorine pesticides has been extensive. Studies conducted in the 1970s and the 1980s have demonstrated 

a widespread and pervasive contamination of air, soil, water, 

and biota by organochlorine compounds, especially the DDT 

degradates and toxaphene. 

During 1995-99, 64 fish-tissue samples were collected at 

52 sites and were analyzed for 28 organochlorine compounds. 

These sites are located in Arkansas, Louisiana, Kentucky, Mississippi, Missouri, and Tennessee, and have drainage basins 

that range from 48 to almost 3,000,000 (Mississippi River) 

km2

. The major physiographic province in the study unit is the 

Mississippi Alluvial Plain, and most (47) of the sites sampled 

lie within this province, although 8 sites were on the main 

stem of the Mississippi River. The Gulf Coastal Plain physiographic province lies on the eastern part of the study unit, and 

the remainder of the sites (5) were within this province.

At least one organochlorine compound was detected in 

every fish-tissue sample analyzed in this study. A degradate 

of p,p’-DDT, p,p’-DDE, was detected in every sample, and 

another degradate, p,p’-DDD was detected in 94 percent of 

the samples. PCBs were detected in 83 percent of the samples. Aldrin, p,p’-methoxychlor, o,p’-methoxychlor, lindane 

(gamma-HCH), alpha-HCH, heptachlorepoxide, and endrin 

were not detected in concentrations above the MRL (generally 5.0 μg/kg) in fish tissue at any of the sites. The percentage 

of detections at each site ranged from 4 (La Grue Bayou near 

DeWitt, Ark.) to 54 percent (Tensas River at Tendal, La.). The 

sites with the highest percentages of detections and the highest concentrations were in the southern part of the study unit, 

excluding the sites located on the Mississippi River. 

Comparing the MISE Study Unit data with the entire 

national NAWQA dataset for sites sampled in 1992-95 and 

with the 1984 NCBP data indicated that fish-tissue samples 

from streams in the MISE Study Unit had some of the highest 

concentrations of organochlorine compounds in the country.

Analyzing the data with respect to land use did not result 

in any statistically significant differences, probably because 

the land use in the study unit is overwhelmingly agricultural. 

Concentrations of some compounds (p,p’-DDT , p,p’-DDD, 

p,p’-DDE, o,p’-DDD, dieldrin, and toxaphene) in fish tissue 

from sites located in Holocene deposits were significantly 

higher than from sites located in Pleistocene deposits. Most of 

the DDT compounds, toxaphene, and mirex had higher concentrations in streams with basins that have low soil permeability. Toxaphene, dieldrin, p,p’-DDE, o,p’-DDE, o,p’-DDD, 

and p,p’-DDD concentrations in fish tissue had higher concentrations from streams with clay as the dominant bed sediment 

particle size; PCB, cis- and trans-chlordane and dieldrin, had 

higher concentrations associated with silt-sized particles. 

The standards for organochlorine compounds in fish tissue that were written for the protection of human health refer 

to the edible portion of the fish and are not directly comparable to the results in this report. There are guidelines for some 

organic compounds in whole-fish tissue for the protection of 

fish-eating wildlife; concentrations of total DDT and toxaphene exceeded the guidelines frequently and are a concern 

in the MISE Study Unit, especially in the southern part of the 

Study Unit. 

Past use of DDT and other organochlorine compounds 

in the MISE Study Unit have made an indelible mark on the 

ecosystem of the area. Although the use of most of these 

pesticides was discontinued in the 1970s and 1980s, some are 

persistent in the environment. Because of their longevity in the 

environment and the hydrophobic nature of these organochlorine compounds, especially DDT and DDT degradates, some 

organochlorine compounds are commonly found in fish tissue 

of the MISE Study Unit. 

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Cooper, C.M., Dendy, F.E., McHenry, J.R., and Ritchie, J.C., 

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Coupe, R.H., 2000, Occurrence of pesticides in five rivers 

of the Mississippi Embayment Study Unit, 1996-98: U.S. 

Geological Survey Water-Resources Investigations Report 

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and Majewski, M.S., 2000, Occurrence of pesticides in rain 

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Crawford, J.K., and Luoma, S.N., 1993, Guidelines for studies 

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Ford, W.M., and Hill, E.P., 1991, Organochlorine pesticides 

in soil sediments and aquatic animals in the upper Steele 

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D.C.: National Center for Food and Agricultural Policy, 

unpaged.

Haag, K.H., and McPherson, B.F., 1997, Organochlorine pesticides and PCBs in southern Florida fishes: Then and now: 

U.S. Geological Survey Fact Sheet FS-110-97, 4 p.

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in 

water resources: Amsterdam, Netherlands, Elsevier, 522 p.

Herbert, C,E., and Keenleyside, K.A., 1995, To normalize or 

not to normalize? Fat is the question: Environmental Toxicology and Chemistry, v. 14, no. 3, p. 801-807.

Leiker, T.J., Madsen, J.E., Deacon, J.R., and Foreman, W.T., 

1995, Methods of analysis by the U.S. Geological Survey 

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Engineering, 1973 [1974], Water quality criteria, 1972: U.S. 

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Nowell, L.H., 1999, Organochlorine pesticides and PCBs in 

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in U.S. freshwater fish, 1996-1986: National Contaminant 

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National Contaminant Biomonitoring Progam: Residues of 

organochlorine chemicals in U.S. freshwater fish, 1976-

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fish: Iowa State University Press, Ames Iowa, 544 p.

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Warwick, P.D., SanFilipo, J.R., Crowley, S.S., Thomas, R.E., 

and Freid, John, 1997, Map showing outcrop of the coalbearing units and land use in the gulf coast region: U.S. 

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Wong, C.S., Capel, P.D., and Nowell, L.H., 2000, Organochlorine pesticides and PCBs in stream sediment and aquatic 

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Water-Resources Investigations Report 00-4053, 88 p.

18 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Tables 19

TABLES
Table 1. Description of fish-tissue sampling sites in the Mississippi Embayment Study Unit, 1995-99

[SA, sand; SL, silt; M, mixed; CL, clay; S, small; L, large; A, agriculture; N, nonagriculture; P, Pleistocene; T, Tertiary; H, Holocene; HI, high; LO, low; MO, moderate; MAP, Mississippi Alluvial Plain; G, Gulf Coastal Plain; MVL, Mississippi Valley Loess; SP, Southeastern Plain; km2, square kilometers; m3/s, cubic meters per second; m, meters; m/s, meters per second; NA, not available] 

Map no. Site name Site Latitude Longi- Geo- Physio- Drainage 1Drain- Domi- Percent Domi- Discharge Channel Mean Instan- Par- 2Per-

(fig. 1) number tude logic graphic basin area age area nant of basin in nant at gage width channel taneous ticle meaage province (km2

) class basin agriculture buffer (m3/s) (m) depth velocity size bility 

and land land- (m) (m/s) class class

ecoregion use use

1 St. Johns Ditch near Sikeston, MO 07043300 365608 893302 P MAP 101 S A 90 A 2.22 10.9 0.52 0.25 SA HI

2 Little River Ditch no. 1 near Morehouse, MO 07043500 365003 894348 P MAP 1,144 S A 85 A 2.96 33.7 0.35 0.13 SA HI

3 Spillway Ditch at Hwy 102 near East Prairie, MO 07024160 364454 892119 M MAP 186 S A 93 A 0.93 10.5 0.40 0.15 SA HI

4 Little River Ditch no. 251 near Lilbourn, MO 07042500 363320 894012 P MAP 627 S A 95 A 3.60 22.4 0.73 0.27 SA HI

5 Obion Creek near Hickman, KY 07023800 363858 890721 P G, MVL 784 S A 77 A 1.22 12.5 0.84 0.17 SL HI

6 Main Ditch at Hwy 153 near White Oak, MO 07041120 361927 900020 P MAP 356 S A 94 A 2.20 19.9 0.33 0.36 SA HI

7 Running Reelfoot Bayou at Hwy 103, TN 07027050 360944 893036 P MAP 751 S A 57 M 0.68 13.9 0.16 0.26 SA HI

8 Elk Chute near Gobler, MO 07046515 361018 895734 P MAP 218 S A 97 A 0.70 11.7 0.20 0.14 SA HI

9 Cockle Burr Slough Ditch near Monette, AR 07040496 355139 901949 P MAP 146 S A 98 A 3.31 53.1 1.06 0.08 SL HI

10 St. Francis River at Lake City, AR 07040450 354916 902556 T MAP 6,150 L N 43 F 11.0 24.6 2.90 0.45 SA MO

11 Cache River at Egypt, AR 07077380 355128 905600 P MAP 1,816 L A 82 A 8.84 21.7 2.34 0.18 SA MO

12 Village Creek near Swifton, AR 07074660 354910 910505 P MAP 410 S A 94 A 4.71 115.8 0.74 0.11 M MO

13 Tyronza River near Twist, AR 07047700 352229 902805 H MAP 1,367 L A 95 A 4.59 19.0 0.81 0.21 SA MO

14 St. Francis River near Coldwater, AR 07047520 352152 903436 P MAP 13,774 L A 70 A 36.1 58.9 1.27 0.46 SA HI

15 Bayou DeView at Morton, AR 07077700 351507 910637 P MAP 1,081 S A 79 A 4.61 28.8 2.62 0.06 SA MO

16 Second Creek near Palestine, AR 07047947 350221 905440 P MAP 111 S A 69 M 2.52 15.1 0.73 0.28 SA LO

17 Wolf River at LaGrange, TN 07030392 350157 891448 T G, MVL 543 S N 32 F 5.04 15.6 1.29 0.30 SA HI

18 L’Anguille River near Palestine, AR 07047950 345820 905310 P MAP 1,983 L A 81 A 8.69 24.6 2.09 0.18 M LO

19 Cache River near Cotton Plant, AR 07077555 350207 911919 P MAP 2,996 L A 83 A 14.6 35.0 2.01 0.22 SA MO

20 Big Creek at Poplar Grove, AR 07077950 343320 905044 P MAP 1,160 S A 87 A 6.33 17.8 2.21 0.23 SL LO

21 LaGrue Bayou near Dewitt, AR 07078040 341900 911657 P MAP 594 S A 77 M 0.00 8.1 0.61 0.00 SA LO

22 Coldwater River at Marks, MS 07279950 341522 901557 T MAP 4,937 L A 65 A 90.7 37.5 4.60 0.50 SL MO

23 Bayou Meto near Bayou Meto, AR 07265099 341205 913145 M MAP 2,078 L A 61 M 0.00 25.5 3.54 0.00 SA MO

24 Cassidy Bayou at Webb, MS 07280900 335659 902028 H MAP 536 S A 89 A 2.41 62.2 0.85 0.04 CL MO

25 Skuna River at Bruce, MS 07283000 335825 892050 T G, SP 668 S N 51 A 0.49 37.4 1.18 0.26 SA MO

26 Quiver River near Doddsville, MS 07288570 333825 902405 H MAP 651 S A 86 A 5.77 16.3 1.65 0.24 SA LO

27 Big Sunflower River at Sunflower, MS 07288500 333250 903235 H MAP 2,010 L A 87 A 15.0 23.2 2.19 0.56 SA LO

28 Bogue Phalia near Leland, MS 07288650 332347 905047 M MAP 1,301 S A 86 A 5.35 37.7 1.34 0.09 SA LO

29 Bayou Macon near Halley, AR 073676595 333216 911736 H MAP 376 S A 93 A 9.80 14.6 1.20 0.45 SA MO

30 Deer Creek near Holandale, MS 07288770 330859 905047 H MAP 231 S A 86 A 0.00 19.2 1.71 0.00 SL MO

20 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 1. Description of fish-tissue sampling sites in the Mississippi Embayment Study Unit, 1995-99 -- Continued

Map no. Site name Site Latitude Longi- Geo- Physio- Drainage 1Drain- Domi- Percent Domi- Discharge Channel Mean Instan- Par- 2Per-

(fig. 1) number tude logic graphic basin area age area nant of basin in nant at gage width channel taneous ticle meaage province (km2) class basin agriculture buffer (m3/s) (m) depth velocity size bility 

and land land- (m) (m/s) class class

ecoregion use use

31 Boeuf River near Arkansas/LA State Line, LA 07367700 325825 912625 H MAP 1,822 L A 91 A 6.17 45.0 2.32 0.07 SA MO

32 Big Sunflower River near Anguilla, MS 07288700 325818 904640 H MAP 6,675 L A 84 A 46.0 89.8 3.98 0.15 CL LO

33 Steele Bayou East Prong near Rolling Fork, MS 07288870 325441 905710 H MAP 1,122 S A 74 A 2.88 49.6 2.02 0.08 SA MO

34 Silver Creek near Bayland, MS 0728872008 325208 904145 H MAP 48 S A 88 A 0.00 20.4 0.13 0.00 M LO

35 Yazoo River below Steele Bayou near Long Lake, MS 07288955 322640 905400 T MAP 34,850 L A 56 M 405 91.4 5.92 0.49 SL MO

36 Tensas River at Tendal, LA 07369500 322555 912200 H MAP 721 S A 87 A 2.35 19.3 1.26 0.26 CL MO

37 Bayou Macon near Delhi, LA 07370000 322725 912830 M MAP 2,141 L A 86 A 6.80 55.4 2.02 0.08 CL LO

38 Big Creek near Sligo, LA 07368580 321220 914911 P MAP 1,311 L A 78 A 1.56 48.4 1.75 0.02 M LO

40 Obion River near Obion, TN 07026040 361423 891304 NA G, MVL 4,861 L NA NA NA NA NA NA NA NA NA41 Hatchie River at Rialto,TN 07030050 353814 893614 NA G, MVL 5,968 L NA NA NA NA NA NA NA NA HI42 White River at DeValls Bluff, AR 07077000 344725 912645 NA MAP 60,765 L NA NA NA NA NA NA NA NA NA43 St. Francis River at Parkin, AR 07047800 352623 903333 NA MAP 6,643* NA NA NA NA NA NA NA NA NA NA44 Bayou Meto near Stuttgart, AR 7264500 342715 913658 M MAP 1,487 L A NA NA NA NA NA NA NA NA

45 Mississippi River at Mile 442 322052090585900 322052 905859 M MAP 2,953,900 L M NA M NA NA NA NA SA NA46 Mississippi River at Mile 460 323501091065500 323501 910655 M MAP 2,953,900 L M NA M NA NA NA NA SA NA47 Mississippi River at Mile 475 324050091054100 324050 910541 M MAP 2,953,900 L M NA M NA NA NA NA SA NA48 Mississippi River at Mile 495 325151091055200 325151 910552 M MAP 2,953,900 L M NA M NA NA NA NA SA NA49 Mississippi River at Mile 378 314625091212600 314625 912126 M MAP 2,953,900 L M NA M NA NA NA NA SA NA50 Mississippi River at Mile 402 315847091072700 315847 910727 M MAP 2,953,900 L M NA M NA NA NA NA SA NA51 Mississippi River at Mile 419 320704091015900 320704 910159 M MAP 2,953,900 L M NA M NA NA NA NA SA NA52 Mississippi River at Mile 432 321651090575800 321651 905758 M MAP 2,953,900 L M NA M NA NA NA NA SA NA53 Steele Bayou at Yazoo National Wildlife Refuge, MS 330743090580300 330743 905803 NA MAP indeterminate NA NA NA NA NA NA NA NA NA NA

*Indeterminate drainage area, values represent total drainage area of St. Francis River and St. Francis Bay

1 Drainage areas were considered large if larger than 1,300 square kilometers and small if less than 1,300 square kilometers2 High permeability is equal or greater than 1.25, moderate permeability is greater than 0.75 and less than 1.25, and low permeability is equal to or less than 0.75 

Tables 21
Table 2. Organochlorine and PCB concentrations in whole fish from sampling sites in the Mississippi Embayment Study Unit, 1995-99

[Concentrations in micrograms per kilogram; <, less than; E, estimated; NA, not available; white background fish species carp; blue bass; yellow gar]

Map Sample Sample Aldrin Poly- Toxa- Pentchlo- Oxy- trans- cis-Non- Mirex p,p’-Me- o,p’-Me- Lindane delta- beta-HCH alpha- Hexanumber number date chlori- phene roanisole chlor- Nonach- achlor thoxy- thoxy- (gamma- HCH HCH chloronated (μg/kg) dane lor chlor chlor HCH) benzene 

biphenyls 

1 1 19980709 <5.00 <50.0 <200 <5.00 <5.00 5.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.002 2 19951018 <5.00 <50.0 <200 <5.00 <5.00 10.0 5.5 <5.00 <5.00 <5.00 <5.00 <5.30 <5.00 <5.00 <5.003 3 19980708 <5.00 59.0 <200 <5.00 <5.00 5.5 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.004 4 19980710 <5.00 62.0 <200 <5.00 <5.00 6.6 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.005 5 19980902 <5.00 394.0 <200 <5.00 9.8 24.1 10.8 <5.00 <5.00 <5.00 <5.00 <12.0 <5.00 <5.00 10.06 6 19980723 <5.00 <50.0 <200 <5.00 <5.00 10.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.007 7 19980708 <5.00 75.0 <200 5.8 <5.00 5.1 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00

8 8 19980625 <5.00 67.0 <200 5.3 <5.00 6.1 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00

9 9 19980625 <5.00 190.0 <200 <5.00 <5.00 11.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00

10 10 19961015 <5.00 100.0 <200 <5.00 E8.10 <5.00 <5.00 <5.00 <10.0 <10.0 NA <5.00 <5.00 <5.00 <5.00

10 11 19980722 <5.00 <50.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0011 12 19950921 <5.00 <50.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0012 13 19980626 <5.00 83.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0013 14 19980707 <5.00 77.0 <200 <5.00 <5.00 6.9 <5.00 <5.00 <5.00 <7.00 <5.00 <5.00 <5.00 <5.00 <5.0014 15 19980707 <5.00 70.0 <200 <5.00 <5.00 5.6 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0015 16 19980624 <5.00 150.0 <200 6.1 <5.00 5.3 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0015 17 19980624 <5.00 74.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0016 18 19980623 <5.00 61.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0017 19 19951019 <5.00 <50.0 <200 <5.00 <5.00 5.1 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0018 20 19961015 <5.00 82.0 <200 <5.00 <5.00 E7.90 <5.00 <5.00 <10.0 <10.0 <6.00 <5.00 <5.00 <5.00 <5.0019 21 19950920 <5.00 <50.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0020 22 19980603 <5.00 73.0 <200 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0021 23 19961016 <5.00 <50.0 <200 <5.00 <5.00 <5.00 <5.00 <10.0 <5.00 <5.00 <5.00 <5.00 NA <5.00 NA22 24 19980604 <5.00 100.0 E390 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <6.00 <5.00 <5.00 <5.00 <5.00 <5.0023 25 19980602 <5.00 240.0 E640 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <6.00 <5.00 <5.00 <5.00 <5.00 <5.0024 26 19951016 <5.00 76.0 2,000.0 <5.00 <5.00 <50.0 <5.00 <5.00 <50.0 <50.0 <6.00 <5.00 <5.00 <5.00 <5.0024 27 19980604 <5.00 150.0 E760 <5.00 <5.00 <6.00 <5.00 <5.00 <12.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0025 28 19951020 <5.00 <50.0 <1100 <5.00 <5.00 5.6 <5.00 13.0 <10.0 <10.0 <5.00 <5.00 <5.60 <5.00 <5.0026 29 19960718 <5.00 62.0 E530 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0026 30 19980617 <5.00 91.0 E750 <5.00 <5.00 12.0 <10.0 <5.00 <17.0 <28.0 <5.00 <5.00 <5.00 <5.00 <5.0027 31 19980617 <5.00 290.0 E710 <5.00 <5.00 <7.00 <5.00 <5.00 <6.00 <9.00 <5.00 <5.00 <5.00 <5.00 <5.0028 32 19950822 <5.00 52.0 1,400.0 <5.00 <5.00 <20.0 <5.00 5.1 <9.00 <12.0 <5.00 <11.0 <10.0 <5.00 <5.00

22 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 2. Organochlorine and PCB concentrations in whole fish from sampling sites in the Mississippi Embayment Study Unit, 1995-99 -- Continued

Map Sample Sample Hepta- Hepta- Endrin Dieldrin p,p’-DDE o,p’-DDE o,p’-DDD p,p’-DDD p,p’-DDT o,p’-DDT Dacthal trans- cisnumber number date chlore- chlor (DCPA) Chlor- Chlropoxide dane dane 

1 1 19980709 <5.00 <5.00 <5.00 <5.00 34.0 <6.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.002 2 19951018 <5.00 <5.00 <5.00 25.0 43.0 <5.00 <5.00 14.0 <5.00 <5.00 <5.00 <5.00 5.03 3 19980708 <5.00 <5.00 <5.00 19.0 24.0 <5.00 <5.00 E5.50 <5.00 <5.00 <5.00 <5.00 <5.004 4 19980710 <5.00 <5.00 <5.00 18.0 140.0 15.0 <5.00 20.0 <5.00 <5.00 <5.00 <5.00 <5.00

5 5 19980902 <5.00 <5.00 <5.00 37.6 42.6 <6.40 <5.00 11.9 <5.00 <5.00 <5.00 7.2 18.96 6 19980723 <5.00 <5.00 <5.00 9.6 220.0 <5.00 <5.00 E22.0 <5.00 <5.00 <5.00 <5.00 6.87 7 19980708 <5.00 <5.00 <6.00 11.0 97.0 <5.00 <5.00 E9.60 <5.00 <5.00 <5.00 <5.00 <5.008 8 19980625 <5.00 <5.00 <5.00 8.9 130.0 <8.00 <5.00 E37.0 6.4 <5.00 <5.00 <5.00 <5.00

9 9 19980625 <5.00 <5.00 <5.00 6.9 290.0 <5.00 <5.00 46.0 6.9 <5.00 <5.00 <5.00 8.3

10 10 19961015 <5.00 <5.00 <5.00 <5.00 550.0 <5.00 E5.50 E29.0 <10.0 <5.00 <5.00 <5.00 <5.0010 11 19980722 <5.00 <5.00 <5.00 <5.00 58.0 <5.00 <5.00 E8.20 <5.00 <5.00 <5.00 <5.00 <5.0011 12 19950921 <5.00 <5.00 <5.00 5.0 120.0 <5.00 <5.00 18.0 <5.00 <5.10 <5.00 <5.00 <5.0012 13 19980626 <5.00 <5.00 <5.00 5.0 87.0 <5.00 <5.00 E13.0 <5.00 <5.00 <5.00 <5.00 <5.0013 14 19980707 <5.00 <5.00 <5.00 8.8 440.0 <5.00 <8.00 <5.00 12.0 <14.0 <5.00 5.1 5.414 15 19980707 <5.00 <5.00 <5.00 7.6 430.0 <5.00 <5.00 42.0 <5.00 <5.00 <5.00 <5.00 <5.0015 16 19980624 <5.00 <5.00 <5.00 15.0 240.0 <5.00 <5.00 26.0 <5.00 <5.00 <5.00 <5.00 <5.0015 17 19980624 <5.00 <5.00 <5.00 8.2 70.0 <5.00 <5.00 E7.20 <5.00 <5.00 <5.00 <5.00 <5.0016 18 19980623 <5.00 <5.00 <5.00 <5.00 91.0 <5.00 <5.00 6.5 <5.00 <5.00 <5.00 <5.00 <5.0017 19 19951019 <5.00 <5.00 <5.00 <5.00 250.0 <5.00 <5.00 42.0 40.0 <5.00 <5.00 <5.00 <5.0018 20 19961015 <5.00 <5.00 <5.00 <5.00 600.0 <5.00 E16.0 E73.0 <10.0 <5.00 <5.00 <5.00 <5.0019 21 19950920 <5.00 <5.00 <5.00 5.4 590.0 <5.00 <5.30 E42.0 <5.00 <5.70 <5.00 <5.00 <5.0020 22 19980603 <5.00 <5.00 <5.00 <5.00 274.0 <5.00 <5.00 E40.5 <5.00 <5.00 <5.00 <5.00 <5.0021 23 19961016 <5.00 <5.00 <11.0 <5.00 94.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0022 24 19980604 <5.00 <5.00 <5.00 9.5 1,300.0 <5.00 <5.00 E300 24.0 <5.00 <5.00 <5.00 <5.00

23 25 19980602 <5.00 <5.00 <5.00 13.0 1,700.0 <5.00 <21.0 E120 13.0 <5.00 <5.00 <5.00 <5.00

24 26 19951016 <5.00 <5.00 <50.0 <50.0 E7300 <50.0 130.0 E2000 64.0 <5.00 <5.00 <50.0 <50.0

24 27 19980604 <5.00 <5.00 <14.0 72.0 3,000.0 <5.00 <29.0 E680 94.0 <40.0 <5.00 <5.00 <5.00

25 28 19951020 <5.00 <5.00 <5.00 11.0 680.0 10.0 12.0 320.0 E21.0 <10.0 <5.00 <5.00 <5.0026 29 19960718 <5.00 <5.00 <5.00 <11.0 E3100 <5.00 <5.00 E600 <10.0 <5.00 <5.00 <5.00 <5.00

26 30 19980617 <5.00 <5.00 <5.00 30.0 5,500.0 <15.0 <55.0 E1100 320.0 <5.00 <5.00 <5.00 9.127 31 19980617 <5.00 <5.00 <15.0 20.0 1,800.0 <11.0 22.0 E380 58.0 <37.0 <5.00 <5.00 <5.00

28 32 19950822 <5.00 <13.0 <220 19.0 5,000.0 16.0 79.0 E850 87.0 56.0 <5.00 <6.00 <5.00

Tables 23
Table 2. Organochlorine and PCB concentrations in whole fish from sampling sites in the Mississippi Embayment Study Unit, 1995-99 -- Continued

Map Sam- Sample Aldrin Poly- Toxa- Pentchlo- Oxy- trans- cis-Non- Mirex p,p’-Me- o,p’-Me- Lindane delta- beta-HCH alpha- Hexanum- ple date chlori- phene roanisole chlor- Nonach- achlor thoxy- thoxy- (gamma- HCH HCH chlorober num- nated (μg/kg) dane lor chlor chlor HCH) benzene ber biphenyls 

28 33 19950822 <5.00 52.0 870.0 <5.00 <5.00 <26.0 <5.00 6.7 <12.0 <15.0 <5.00 <5.00 <12.0 <5.00 <5.0028 34 19990830 <5.00 <50.0 E980 <5.00 <5.00 6.3 <5.00 E4.20 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0029 35 19980616 <5.00 150.0 E650 <5.00 <5.00 <8.00 <5.00 <5.00 <5.00 <8.00 <5.00 <5.00 <5.00 <5.00 <5.0030 36 19960717 <5.00 260.0 E3900 <12.0 <5.00 <35.0 <420 <5.00 <5.00 <17.0 <10.0 <5.00 <5.00 <9.00 <5.0031 37 19980616 <5.00 86.0 <200 <5.00 <5.00 7.6 <5.00 <5.00 <5.00 <7.00 <5.00 <5.00 <5.00 <5.00 <5.0032 38 19950821 <5.00 50.0 2,100.0 <5.00 <5.00 <10.0 <7.00 5.7 <5.00 <25.0 <5.00 <5.00 <5.00 <5.00 <5.0033 39 19950824 <5.00 60.0 9,100.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <18.0 <5.00 <5.00 <5.00 <5.00 <5.0034 40 19980608 <5.00 87.0 E550 5.1 <5.00 <5.00 <5.00 <5.00 <12.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0035 41 19950823 <5.00 250.0 4,700.0 <5.30 <5.00 8.6 <5.00 6.3 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0035 42 19950928 <5.00 200.0 1,600.0 11.0 <5.00 15.0 11.0 <5.00 <10.0 <13.0 <5.00 <5.00 <5.00 <5.00 <5.0035 43 19961205 <5.00 200.0 <200 <5.00 <5.00 <10.0 <10.0 5.8 <10.0 <10.0 <5.00 <5.00 <5.00 <5.00 <5.0036 44 19950825 <5.00 77.0 12,000.0 <5.00 9.7 19.0 29.0 96.0 <17.0 <5.00 <5.00 6.4 <5.00 <5.00 <5.0036 45 19990901 <5.00 <50.0 E1400 <5.00 <5.00 10.0 E4.90 75.0 <5.00 <14.0 <5.00 <5.00 <5.00 <5.00 <5.0037 46 19950918 <5.00 69.0 <1800 <5.00 <5.00 5.6 7.6 41.0 <10.0 <15.0 <5.00 <5.40 <5.00 <5.00 <5.0038 47 19980601 <5.00 170.0 1,200.0 <5.00 <5.00 <5.00 <5.00 50.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0040 48 19950922 <5.00 150.0 <200 <5.00 <5.00 9.8 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 5.4 <5.00 <5.0041 49 19951017 <5.00 320.0 <200 <22.0 <5.00 25.0 11.0 <5.00 <5.00 <9.00 <5.00 <9.00 <5.00 <5.00 <5.0042 50 19950919 <5.00 130.0 <200 <5.00 6.4 7.2 <5.00 <5.00 <10.0 <11.0 <5.00 <6.60 <5.00 <8.00 <5.00

43 51 19961015 <5.00 83.0 <200 <5.00 E5.40 E6.40 <5.00 <5.00 <10.0 <10.0 <7.00 <5.00 <5.00 <5.00 <5.0044 52 19961016 <5.00 77.0 <200 <9.00 <5.00 E9.90 <5.00 <10.0 <5.00 <5.00 <5.00 <5.00 NA <5.00 NA

45 53 19961119 <5.00 160.0 <200 <5.00 <5.00 11.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0046 54 19961119 <5.00 180.0 <200 <5.00 <5.00 12.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0047 55 19961120 <5.00 200.0 <400 <10.0 <10.0 <10.0 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <5.0047 56 19961120 <5.00 530.0 <400 <10.0 <10.0 E9.40 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 5.348 57 19961120 <5.00 270.0 <400 <10.0 <10.0 <10.0 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <5.0049 58 19961121 <5.00 240.0 <200 <5.00 <5.00 E11.0 <10.0 6.1 <10.0 <10.0 <5.00 <5.00 <5.00 <5.00 <5.0050 59 19961121 <5.00 160.0 <200 <5.00 <5.00 <10.0 <10.0 <5.00 <10.0 <10.0 <5.00 <5.00 <5.00 <5.00 <5.0051 60 19961122 <5.00 560.0 <400 <10.0 <10.0 E15.0 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <5.0052 61 19961122 <5.00 740.0 <400 <10.0 <10.0 E16.0 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 5.452 62 19961122 <5.00 720.0 <400 <10.0 <10.0 E10.0 <10.0 <5.00 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <5.0053 63 19990628 <5.00 52.0 <200 <5.00 <5.00 <8.80 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.0053 64 19990628 <5.00 140.0 <200 E4.70 <5.00 E11.0 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00 <5.00

24 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 2. Organochlorine and PCB concentrations in whole fish from sampling sites in the Mississippi Embayment Study Unit, 1995-99 -- Continued

Map Sample Sample Hepta- Hepta- Endrin Dieldrin p,p’-DDE o,p’-DDE o,p’-DDD p,p’-DDD p,p’-DDT o,p’-DDT Dacthal trans- cisnumber number date chlore- chlor (DCPA) Chlor- Chlropoxide dane dane 

28 33 19950822 <5.00 <5.00 <200 16.0 E5100 19.0 68.0 E680 520.0 53.0 <5.00 <5.00 <5.00

28 34 19990830 <5.00 <5.00 <5.00 6.2 2,700.0 E6.80 29.0 560.0 34.0 32.0 <5.00 <5.00 <5.00

29 35 19980616 <5.00 <5.00 <5.00 9.5 1,000.0 <5.00 11.0 E98.0 16.0 <14.0 <5.00 <5.00 <5.0030 36 19960717 <5.00 <5.00 <56.0 <78.0 E5400 64.0 <5.00 E1500 <55.0 <5.00 <5.00 E23.0 E23.0

31 37 19980616 <5.00 <5.00 <5.00 8.6 640.0 <5.00 <13.0 E190 14.0 <17.0 <5.00 <5.00 <5.00

32 38 19950821 <5.00 <5.00 <15.0 23.0 3,700.0 28.0 100.0 E1100 87.0 35.0 <5.00 <5.00 <6.00

33 39 19950824 <5.00 <5.00 <5.00 16.0 3,700.0 <12.0 120.0 E1100 E140 <5.30 <5.00 <5.00 <5.00

34 40 19980608 <5.00 <5.00 <11.0 20.0 1,200.0 <5.00 <21.0 E370 160.0 <5.00 <5.00 <5.00 <5.00

35 41 19950823 <5.00 <5.00 <5.00 32.0 2,700.0 <5.00 140.0 E1700 E390 <5.00 <5.00 7.3 8.0

35 42 19950928 <5.00 <5.00 <5.40 32.0 1,600.0 18.0 48.0 550.0 E42.0 <10.0 <5.00 9.9 14.035 43 19961205 <10.0 <5.00 <5.00 9.3 730.0 <10.0 13.0 390.0 E10.0 <10.0 <5.00 <10.0 <10.0

36 44 19950825 <5.00 11.0 <9.50 23.0 5,300.0 17.0 E14.0 E1800 E36.0 <5.00 <5.30 <5.00 10.0

36 45 19990901 <5.00 <5.00 <12.0 5.9 2,500.0 E4.30 28.0 570.0 42.0 50.0 <5.00 <5.00 <5.00

37 46 19950918 <5.00 <5.00 <6.80 19.0 4,600.0 22.0 54.0 610.0 E29.0 <10.0 5.2 <5.00 5.1

38 47 19980601 <5.00 <5.00 <5.00 <5.00 2,700.0 <5.00 20.0 250.0 43.0 33.0 <5.00 <5.00 <5.0040 48 19950922 <5.00 <5.00 <5.00 5.3 36.0 <5.00 <5.00 E10.0 <5.00 <5.00 <5.00 <5.00 6.441 49 19951017 <5.00 <6.00 <43.0 27.0 220.0 <6.00 <16.0 5.5 <6.00 <7.00 10.0 15.0

42 50 19950919 <5.00 <5.00 <5.00 <5.00 150.0 <5.20 <5.00 E13.0 <10.0 <10.0 <5.00 <5.00 <5.0043 51 19961015 <5.00 <5.00 <5.00 <5.00 1,200.0 <5.00 E9.90 E150 E7.90 <5.00 <5.00 <5.00 <5.0044 52 19961016 <5.00 <5.00 <5.00 8.1 770.0 <5.00 8.9 50.0 <5.00 <5.00 <5.00 <5.00 <5.00

45 53 19961119 <5.00 <5.00 <5.00 20.0 470.0 <5.00 <11.0 150.0 6.0 <11.0 <5.00 7.2 10.0

46 54 19961119 <5.00 <5.00 <5.00 29.0 81.0 <5.00 <5.00 E26.0 <5.00 <5.00 <5.00 8.3 12.047 55 19961120 <10.0 <5.00 <10.0 E15.0 140.0 <10.0 <10.0 E8.40 <10.0 <10.0 <10.0 <10.0 <10.047 56 19961120 <10.0 <5.00 <10.0 E23.0 120.0 <10.0 <10.0 E8.80 <10.0 <10.0 <10.0 <10.0 E8.3048 57 19961120 <10.0 <5.00 <10.0 E15.0 130.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.049 58 19961121 <10.0 <5.00 <5.00 50.0 590.0 <10.0 6.9 120.0 <10.0 <10.0 <5.00 <10.0 E11.0

50 59 19961121 <10.0 <5.00 <5.00 18.0 E52.0 <10.0 <5.00 36.0 <10.0 <10.0 <5.00 <10.0 <10.051 60 19961122 <10.0 <5.00 <10.0 E23.0 300.0 <10.0 E9.50 90.0 <10.0 <10.0 <10.0 E9.80 E12.052 61 19961122 <10.0 <5.00 <10.0 E30.0 170.0 <10.0 <10.0 E19.0 <10.0 <10.0 <10.0 E9.50 E12.052 62 19961122 <10.0 <5.00 <10.0 E23.0 160.0 <10.0 <10.0 E14.0 <10.0 <10.0 <10.0 E7.30 E8.7053 63 19990628 <5.00 <5.00 <5.00 15.0 2,300.0 <5.00 <34.0 430.0 45.0 <44.0 <5.00 <5.00 <5.2053 64 19990628 <5.00 <5.00 <5.00 24.0 1,500.0 <5.00 <5.00 340.0 70.0 <5.00 <5.00 <5.00 E8.30

Tables 25
Table 3. Physical characteristics of composited fish-tissue samples collected from streams in the Mississippi Embayment Study Unit, 

1995-99.

[CCA, Common carp species; LOC, spotted gar species; MSP, black bass species; mm, millimeters]

Map number Sample 

number

Number of 

individuals

Weight

(grams)

Species Average 

weight 

(grams)

Average age

(year)

Average total 

length

(mm)

Lipids

(percent)

1

2

3

4

5

6

7

8

9

10

10

11

12

13

14

15

15

16

17

18

19

20

21

22

23

24

24

25

26

26

27

28

28

28

29

30

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

8

8

5

8

8

8

8

5

8

7

8

8

5

8

6

8

5

5

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

6

8

8

14,854

12,509

1,963

14,069

14,184

16,834

11,634

10,734

19,192

15,339

3,547

13,550

9,614

12,737

9,857

15,909

2,883

2,329

4,040

13,794

12,522

10,457

15,976

11,954

19,116

12,607

12,459

17,032

5,408

16,481

16,091

8,832

4,102

8,580

11,669

15,861

CCA

CCA

MSP

CCA

CCA

CCA

CCA

CCA

CCA

CCA

MSP

CCA

CCA

CCA

CCA

CCA

MSP

LOC

MSP

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

LOC

CCA

CCA

CCA

1,857

1,564

393

1,759

1,773

2,104

1,454

2,147

2,399

2,191

443

1,694

1,923

1,592

1,643

1,989

577

466

505

1,724

1,565

1,307

1,997

1,494

2,390

1,576

1,557

2,129

676

2,060

2,011

1,104

513

1,430

1,459

1,983

4.6

4.2

3.0

4.8

5.0

5.1

4.0

5.0

5.1

NA

2.5

3.3

4.4

4.4

4.2

4.3

3.4

NA

3.3

3.2

3.0

4.3

4.0

3.9

5.1

3.0

4.9

4.0

NA

5.4

4.9

2.8

NA

4.2

4.4

NA

499

489

290

506

507

545

432

532

554

531

301

482

523

491

501

519

312

505

338

502

496

353

534

399

443

490

389

551

382

512

521

425

528

474

480

503

7.7

5.1

6.0

5.2

14.0

8.3

13.0

21.0

8.1

8.9

7.4

4.4

5.0

9.7

5.7

5.8

3.0

1.8

4.4

8.4

8.3

3.9

3.4

4.8

7.3

8.4

4.8

13.0

3.2

9.1

6.8

4.3

4.1

3.9

3.8

9.4

26 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 3. Physical characteristics of composited fish-tissue samples collected from streams in the Mississippi Embayment Study Unit, 

1995-99---Continued.

Map number Sample 

number

Number of 

individuals

Weight

(grams)

Species Average 

weight 

(grams)

Average age

(year)

Average total 

length

(mm)

Lipids

(percent)

31

32

33

34

35

35

35

36

36

37

38

40

41

42

43

44

45

46

47

47

48

49

50

51

52

52

53

53

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

8

8

8

8

8

8

8

8

5

8

8

8

8

8

8

8

6

8

8

8

8

8

5

8

8

8

8

8

12,112

6,394

5,728

12,116

5,451

23,516

21,463

11,651

7,551

15,239

10,174

12,324

16,665

19,558

15,337

14,566

22,764

22,875

19,569

21,121

26,411

19,183

14,597

27,679

26,515

26,544

12,903

14,032

CCA

CCA

CCA

CCA

LOC

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

CCA

1,514

799

716

1,515

681

2,940

2,683

1,456

1,510

1,905

1,272

1,541

2,083

2,445

1,917

1,820

3,794

2,859

2,446

2,640

3,301

2,398

2,919

3,460

3,314

3,318

1,613

1,754

4.4

2.8

2.6

4.4

NA

3.7

NA

2.8

4.4

3.8

4.1

3.3

3.9

4.2

3.2

4.1

4.7

4.2

4.1

4.57

5.14

4.4

4.5

4.6

4.6

4.5

NA

NA

453

402

377

386

565

574

563

481

482

520

389

484

536

559

527

511

627

545

534

550

596

534

563

598

600

611

490

506

4.9

4.6

7.8

5.0

13.0

14.0

12.0

9.3

6.9

6.7

11.0

6.1

14.0

13.0

7.6

7.5

7.7

7.0

7.0

14.0

9.6

28.0

18.0

9.4

9.3

9.7

4.2

1.5

Tables 27
Table 4. Concurrent samples analyzed by the National Water Quality Laboratory and the National Contaminant Biomonitoring Program, 1995

[Concentrations in micrograms per kilogram; No., number; BEST, Biomonitoring of Environmental Status and Trends; A, Male carp; B, female carp; C, male bass; D, female bass; <, less than; E, estimated; NA, not available; blue is data collected for the National Water Quality Assessment Program; yellow is data collected for the Biomonitoring of Environmental Status and Trends Program]

Site name BEST Map Sample Poly-chlorinated Toxaphene Oxychlordane trans-Nonachlor cis-Nonachlor Mirex 

Site Id number date biphenyls 

Little River Ditch no. 1 212-A 2 18-Oct <50.0 52 <200 <50 <5.0 <10 10.0 13 5.50 <10 <5.0 <10

near Morehouse, MO 212-B <50 <50 <10 10 <10 <10

212-C <50 <50 <10 <10 <10 <10

212-D 130 <50 <10 <10 <10 <10

Cache River at Egypt, 208-A 11 21-Sep <50.0 56 <200 <50 <5.0 <10 <5.0 20 <5.0 <10 <5.0 <10

AR 208-B 53 <50 <10 <10 <10 <10

Wolf River at LaGrange, 213-A 17 19-Oct <50.0 <50 <200 <50 <5.0 <10 5.10 <10 <5.0 <10 <5.0 <10

TN 213-B <50 <50 <10 <10 <10 <10

Cache River near Cotton 207-A 19 20-Sep <50.0 72 <200 <50 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

Plant, AR 207-B <50 <50 <10 <10 <10 <10

Bogue Phalia near Le- 202-A 28 22-Aug 52.0 75 1,400 5,200 <5.0 <10 <20.0 42 <5.0 <10 5.10 <10

land, MS 202-B <50 2,700 <10 21 <10 <10

Big Sunflower River near 201-A 32 21-Aug 50.0 100 2,100 8,300 <5.0 <10 <10.0 100 <7.0 <10 5.70 <10

Anguilla, MS 201-B <50 1,900 <10 29 <10 <10

Steele Bayou East Prong 203-A 33 24-Aug 60.0 59 9,100 2,500 <5.0 <10 <5.0 31 <5.0 <10 <5.0 <10

near Rolling Fork, MS 203-B <50 1,900 <10 25 <10 <10

Yazoo River, MS ** 80-A 35 23-Aug 200 360 1,600 2,400 <5.0 <10 15.0 32 11.0 <10 <5.0 <10

80-B 240 820 <10 17 <10 <10

80-C 120 520 <10 <10 <10 <10

80-D 160 740 <10 10 <10 <10

Tensas River at Tendal, 204-A 36 25-Aug 77.0 86 12,000 3,100 9.70 <10 19.0 38 29.0 <10 96.0 75

LA 204-B <50 2,200 <10 29 <10 42

** Note: BEST sampling site located upstream of National Water-Quality Program sampling site

28 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 4. Concurrent samples analyzed by the National Water Quality Laboratory and the National Contaminant Biomonitoring Program, 1995 -- Continued

Site name BEST Map Sample Lindane delta-HCH beta-HCH alpha-HCH Hexachloro-ben- Heptachlor 

Site Id number date (gamma-BHC) zene 

Little River Ditch no. 1 212-A 2 18-Oct <5.0 <10 <5.30 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

near Morehouse, MO 212-B <10 <10 <10 <10 <10 <10

212-C <10 <10 <10 <10 <10 <10

212-D <10 <10 <10 <10 <10 <10

Cache River at Egypt, AR 208-A 11 21-Sep <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

208-B <10 <10 <10 <10 <10 <10

Wolf River at LaGrange, 213-A 17 19-Oct <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

TN 213-B <10 <10 <10 <10 <10 <10

Cache River near Cotton 207-A 19 20-Sep <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

Plant, AR 207-B <10 <10 <10 <10 <10 <10

Bogue Phalia near Le- 202-A 28 22-Aug <5.0 <10 <11.0 <10 <10.0 <10 <5.0 <10 <5.0 <10 <13.0 <10

land, MS 202-B <10 <10 <10 <10 <10 <10

Big Sunflower River near 201-A 32 21-Aug <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

Anguilla, MS 201-B <10 <10 <10 <10 <10 <10

Steele Bayou East Prong 203-A 33 24-Aug <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

near Rolling Fork, MS 203-B <10 <10 <10 <10 <10 <10

Yazoo River, MS ** 80-A 35 23-Aug <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 <10 <5.0 10

80-B <10 <10 <10 <10 <10 <10

80-C <10 <10 <10 <10 <10 <10

80-D <10 <10 <10 <10 <10 <10

Tensas River at Tendal, 204-A 36 25-Aug <5.0 <10 6.40 <10 <5.0 <10 <5.0 <10 <5.0 <10 11.0 <10

LA 204-B <10 <10 <10 <10 <10 <10

Tables 29
Table 4. Concurrent samples analyzed by the National Water Quality Laboratory and the National Contaminant Biomonitoring Program, 1995 -- Continued

Site name BEST Site Map Sample Endrin Dieldrin p,p’-DDE o,p’-DDE o,p’-DDD p,p’-DDD 

Id number date

Little River Ditch no. 1 212-A 2 18-Oct <5.00 <10 25.0 33 43.0 56 <5.0 <10 <5.0 <10 14.0 15

near Morehouse, MO 212-B <10 30 57 <10 <10 18

212-C <10 <10 29 <10 <10 <10

212-D <10 <10 12 <10 <10 <10

Cache River at Egypt, 208-A 11 21-Sep <5.0 <10 5.0 17 120 180 <5.0 <10 <5.0 <10 18.0 28

AR 208-B <10 10 120 <10 <10 17

Wolf River at LaGrange, 213-A 17 19-Oct <5.0 <10 <5.0 <10 250 100 <5.0 <10 <5.0 <10 42.0 11

TN 213-B <10 <10 96 <10 <10 12

Cache River near Cotton 207-A 19 20-Sep <5.0 <10 5.40 13 590 510 <5.0 <10 <5.30 <10 E42.0 61

Plant, AR 207-B <10 <10 210 <10 <10 29

Bogue Phalia near Le- 202-A 28 22-Aug <220 <10 19.0 47 5,000 4,300 16.0 <10 79.0 120 E850 1,500

land, MS 202-B <10 <10 4,200 <10 72 1,200

Big Sunflower River near 201-A 32 21-Aug <15.0 <10 23.0 34 3,700 8,300 28.0 <10 100 250 E1100 2,800

Anguilla, MS 201-B <10 16 3,100 <10 73 1,000

Steele Bayou East Prong 203-A 33 24-Aug <5.0 <10 16.0 12 3,700 5,200 <12.0 <10 120 65 E1100 1,000

near Rolling Fork, MS 203-B <10 12 3,300 <10 53 800

Yazoo River, MS ** 80-A 35 23-Aug <5.4 <10 32.0 54 1,600 2,000 18.00 <10 48 59 550.00 760

80-B <10 41 1,000 <10 34 280

80-C <10 24 430 <10 <10 160

80-D <10 29 530 <10 <10 200

Tensas River at Tendal, 204-A 36 25-Aug <9.50 <10 23.0 <10 5,300 5,800 17.0 <10 E14.0 87 E1800 1,500

LA 204-B <10 14 2,900 <10 70 1,100

30 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 4. Concurrent samples analyzed by the National Water Quality Laboratory and the National Contaminant Biomonitoring Program, 

1995 -- Continued

Site name BEST Map Sample p,p’-DDT o,p’-DDT trans-Chlordane cis-Chlordane 

Site Id number date

Little River Ditch no. 1 212-A 2 18-Oct <5.0 <10 <5.0 <10 <5.0 <10 5.0 <10

near Morehouse, MO 212-B <10 <10 <10 <10

212-C <10 <10 <10 <10

212-D <10 <10 <10 <10

Cache River at Egypt, AR 208-A 11 21-Sep <5.0 <10 <5.10 <10 <5.0 <10 <5.0 12

208-B <10 <10 <10 <10

Wolf River at LaGrange, 213-A 17 19-Oct 40.0 <10 <5.0 <10 <5.0 <10 <5.0 <10

TN 213-B <10 <10 <10 <10

Cache River near Cotton 207-A 19 20-Sep <5.0 <10 <5.7 <10 <5.0 <10 <5.0 <10

Plant, AR 207-B <10 <10 <10 <10

Bogue Phalia near Le- 202-A 28 22-Aug 87.0 <10 56.0 <10 <6.0 <10 <5.0 <10

land, MS 202-B <10 <10 <10 <10

Big Sunflower River near 201-A 32 21-Aug 87.0 <10 35.0 <10 <5.0 <10 <6.0 <10

Anguilla, MS 201-B <10 <10 <10 <10

Steele Bayou East Prong 203-A 33 24-Aug E140 <10 <5.3 <10 <5.0 <10 <5.0 <10

near Rolling Fork, MS 203-B <10 <10 <10 <10

Yazoo River, MS ** 80-A 35 23-Aug E42 <10 <10 <10 9.90 <10 14.0 <10

80-B <10 <10 <10 1080-C 75.0 <10 <10 11

80-D 110.0 <10 <10 <10

Tensas River at Tendal, 204-A 36 25-Aug E36.0 <10 <5.0 <10 <5.0 <10 10.0 <10

LA 204-B <10 <10 <10 <10

Tables 31
Table 5. Relative percent difference for selected organochlorine compounds between duplicate and multi-year fish-tissue samples collected in the Mississippi Embayment Study Unit 1995-99 

[RPD, relative percent difference; <, less than; NA, not applicable; bold is mean; concentrations in micrograms per kilogram]

Duplicate Multi-year

concentrations concentrations Map Map 

Compound number Sample 1 Sample 2 RPD number Sample 1 Sample 2 RPD

PCB 52 740 720 2.74 24 76 150 65.49

47 200 530 90.41 35 200 200 0.00

53 52 140 91.67 26 62 91 37.91

61.61 28 52 <50 NA

36 77 <50 NA

34.47

trans-nonachlor 52 16 10 46.15 36 19 10 62.07

28 <20 6.3 NA

26 <5 12 NA

35 15 <10 NA

dieldrin 52 30 23 26.42 26 <11 30 NA

47 15 23 42.11 35 32 9.3 109.93

53 15 24 46.15 36 23 5.9 118.34

38.22 28 19 6.2 101.59

24 <50 72 NA

109.95

p,p’-DDE 52 170 160 6.06 24 7300 3000 83.50

47 140 120 15.38 26 3100 5500 55.81

53 2300 1500 42.11 28 5000 2700 59.74

21.18 35 1600 730 74.68

36 5300 2500 71.79

69.10

p,p’-DDT 52 19 14 30.30 24 64 94 37.97

53 45 70 43.48 28 87 34 87.60

36.89 35 42 10 123.08

36 36 42 15.38

26 <10 320 NA

66.01

32 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 5. Relative percent difference for selected organochlorine compounds between duplicate and multi-year fish-tissue samples collected in the Mississippi Embayment Study Unit 1995-99--Continued 

Compound

Map 

number

Duplicate 

concentrations

Sample 1 Sample 2 RPD

Map 

number

Multi-year

concentrations

Sample 1 Sample 2 RPD

p,p’-DDD

trans-chlordane

cis-chlordane

Percent lipids

53

52

52

52

47

53

430

9.5

12

7

9.3

4.2

340

7.3

8.7

14

9.7

1.5

23.38

26.19

31.88

66.67

4.21

94.74

24

26

28

35

36

35

35

36

24

26

28

35

36

2000

600

850

550

1800

9.9

14

10

8.4

3.2

4.3

14

9.3

680

1100

560

390

570

<10

<10

<5

4.8

9.1

3.9

12

6.9

98.51

58.82

41.13

34.04

103.80

67.26

NA

NA

NA

54.55

95.93

9.76

15.38

29.63

49.47

41.05

Table 6. Results of analysis of variance on weight, age, and total length for fish collected in subsequent years 

[N, there was no significant difference at the 0.05 level, Y+ there was a significant difference and the value increased between years; NA, 

data not available]

Map number Sample number Years Weight Age Total length Lipids percent

24 26 and 27 1995 and 98 N Y+ N 8.4 – 4.8

26 29 and 30 1996 and 98 Y+ NA Y+ 3.2 – 9.1

28 32 and 34 1995 and 99 N N N 4.3 – 3.9

35 42 and 43 1995 and 96 N NA N 14 - 12

36 44 and 45 1995 and 99 N Y+ N 9.3 – 6.9

Tables 33
Table 7. Statistical summary of concentrations of organochlorine compounds and PCBs analyzed in fish tissue collected 

in the Mississippi Embayment Study Unit, 1995-99

[Concentrations in micrograms per kilogram; <, less than; MRL, method reporting limit; NYFF, New York Fish Flesh Criteria; NAS/NAE, 

National Academy of Sciences and National Academy of Engineering]

Organochlorine 

compound 

NYFF 

criteria

NAS/NAE

guidelines

Number of 

samples Minimum

Percentiles 

25th 50th 75th Maximum

Cyclodiences, chlorinated benzene derivatives, and polychloroterpenes

Aldrin 

Chlordane

trans-Chlordane 

cis-Chlordane 

trans-Nonachlor 

cis-Nonachlor 

 Oxychlordane 

Dieldrin 

Endrin 

Heptachlor 

Heptachlorepoxide 

Hexachlorobenzene 

Toxaphene 

Mirex 

p,p’-Methoxychlor 

o,p’-methoxychlor 

Dacthal (DCPA) 

Pentchloroanisole 

delta-HCH 

beta-HCH 

 Lindane (gammaHCH) 

alpha-HCH

Total HCH

2

120

500

2

120

25

200

200

330

100

1

100

3

100

1

100

1

100

1

100

1

100

1

100

1

100

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

64

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<200

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

Diphenyl aliphatics

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

5.8

<5.0

<5.0

<5.0

<5.0

<200

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

5.8

<5.0

<5.0

14.0

<5.0

<5.0

<5.0

<5.0

<200

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

5.0

8.1

10.0

5.0

<5.0

23.0

5.0

<5.0

<5.0

<5.0

665

<5.0

5.0

5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

25.0

25.0

25.0

210.0

9.8

72.0

<MRL

11.0

5.0

10.0

12,000

96.0

<MRL

<MRL

5.2

11.0

6.4

6.0

<MRL

5.0

p,p’-DDE

o,p’-DDE

o,p’-DDD 

p,p’-DDD 

p,p’-DDT 

o,p’-DDT 

Total DDT 4

200 41000

64 24

64 <5.0

64 <5.0

64 <5.0

64 <5.0

64 <5.0

Polychlorinated biphenyls 

130

<5.0

<5.0

14.0

<5.0

<5.0

510

<5.0

5.0

50

5.3

<5.0

1,925

5.0

14.1

410

37

5.0

7,300

64

140

2,000

520

56

Polychlorinated 

biphenyls 

500 64 <50 59.8 83.0 182.5 740.0

1

Applies to total residues of aldrin, BHC, chlordane, dieldrin, endosulfan, endrin, heptachlor, heptachlor epoxide, lindane, and toxaphene, 

either singly or in combination. 

2

Applies to sum of aldrin and dieldrin

3

Includes cis- and trans-chlordane, cis- and trans-nonachlor, oxychlordane, but not heptachlor epoxide.

4

Applies to total residues of DDT, DDE, and DDD.

34 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
Table 8. DDT and DDT degradate concentrations, total DDT concentrations, and DDT, DDE, and DDD to total DDT ratios for fish-tissue 

samples collected in the Mississippi Embayment Study Unit, 1995-99

[Concentrations in micrograms per kilogram; NA, not available; <, less than]

Map 

number 

(fig. 1)

Sample 

number

Concentrations Percent

p,p'-DDE o,p'-DDE o,p'-DDD p,p'-DDD p,p'-DDT o,p'-DDT 2

Total

DDT

p,p'-DDT p,p'-DDE p,p'-DDD

1

2

3

4

5

6

7

8

9

10

10

11

12

13

14

15

15

16

17

18

19

20

21

22

23

24

24

25

26

26

27

28

28

28

29

30

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

34

43

24

140

43

220

97

130

290

550

58

120

87

440

430

240

70

91

250

600

590

274

94

1,300

1,700

7,300

3,000

680

3,100

5,500

1,800

5,000

5,100

2,700

1,000

5,400

0.0

0.0

0.0

15.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

10.0

0.0

0.0

0.0

16.0

19.0

6.8

0.0

64.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

5.5

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

16.0

0.0

0.0

0.0

0.0

0.0

130.0

0.0

12.0

0.0

0.0

22.0

79.0

68.0

29.0

11.0

0.0

0.0

14.0

5.5

20.0

11.9

22.0

9.6

37.0

46.0

29.0

8.2

18.0

13.0

0.0

42.0

26.0

7.2

6.5

42.0

73.0

42.0

40.5

0.0

300.0

120.0

2,000.0

680.0

320.0

600.0

1,100.0

380.0

850.0

680.0

560.0

98.0

1,500.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

6.4

6.9

0.0

0.0

0.0

0.0

12.0

0.0

0.0

0.0

0.0

40.0

0.0

0.0

0.0

0.0

24.0

13.0

64.0

94.0

21.0

0.0

320.0

58.0

87.0

520.0

34.0

16.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

56.0

53.0

32.0

0.0

0.0

34

57

30

175

55

242

107

173

343

585

66

138

100

452

472

266

77

98

332

689

632

315

94

1,624

1,833

9,494

3,774

1,043

3,700

6,920

2,260

6,088

6,440

3,362

1,125

6,964

0.0

0.0

0.0

0.0

0.0

0.0

0.0

3.7

2.0

0.0

0.0

0.0

0.0

2.7

0.0

0.0

0.0

0.0

12.0

0.0

0.0

0.0

0.0

1.5

0.7

0.7

2.5

2.0

0.0

4.6

2.6

2.3

8.9

2.0

1.4

0.0

100.0

75.4

81.4

80.0

78.2

90.9

91.0

75.0

84.6

94.1

87.6

87.0

87.0

97.3

91.1

90.2

90.7

93.3

75.3

87.1

93.4

87.1

100.0

80.0

92.7

76.9

79.5

65.2

83.8

79.5

79.6

82.1

79.2

80.3

88.9

77.5

0.0

24.6

18.6

11.4

21.8

9.1

9.0

21.3

13.4

5.0

12.4

13.0

13.0

0.0

8.9

9.8

9.3

6.7

12.7

10.6

6.6

12.9

0.0

18.5

6.5

21.1

18.0

30.7

16.2

15.9

16.8

14.0

10.6

16.7

8.7

21.5

Tables 35
Table 8. DDT and DDT degradate concentrations, total DDT concentrations, and DDT, DDE, and DDD to total DDT ratios for fish-tissue 

samples collected in the Mississippi Embayment Study Unit, 1995-99--Continued

Map 

number 

(fig. 1)

Sample 

number

Concentrations Percent

p,p'-DDE o,p'-DDE o,p'-DDD p,p'-DDD p,p'-DDT o,p'-DDT 2

Total

DDT

p,p'-DDT p,p'-DDE p,p'-DDD

31

32

33

34

35

35

35

36

36

37

38

40

41

42

43

44

45

46

47

47

48

49

50

51

52

52

53

53

Max

Median

Min

Mean

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

640

3,700

3,700

1,200

2,700

1,600

730

5,300

2,500

4,600

2,700

36

220

150

1,200

770

470

81

140

120

130

590

52

300

170

160

2,300

1,500

0.0

28.0

0.0

0.0

0.0

18.0

0.0

17.0

4.3

22.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

100.0

120.0

0.0

140.0

48.0

13.0

14.0

28.0

54.0

20.0

0.0

0.0

0.0

9.9

8.9

0.0

0.0

0.0

0.0

0.0

6.9

0.0

9.5

0.0

0.0

0.0

0.0

190.0

1,100.0

1,100.0

370.0

1,700.0

550.0

390.0

1,800.0

570.0

610.0

250.0

10.0

 NA

13.0

150.0

50.0

150.0

26.0

8.4

8.8

0.0

120.0

36.0

90.0

19.0

14.0

430.0

340.0

14.0

87.0

140.0

160.0

390.0

42.0

10.0

36.0

42.0

29.0

43.0

0.0

5.5

0.0

7.9

0.0

6.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

45.0

70.0

0.0

35.0

0.0

0.0

0.0

0.0

0.0

0.0

50.0

0.0

33.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

844

5,050

5,060

1,730

4,930

2,258

1,143

7,167

3,194

5,315

3,046

46

226

163

1,368

829

626

107

148

129

130

717

88

400

189

174

2,775

1,910

9,494

585

30

1,714

1.7

2.4

2.8

9.2

7.9

1.9

0.9

0.5

2.9

0.5

2.5

0.0

2.4

0.0

0.6

0.0

1.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1.6

3.7

12.0

0.0

0.0

1.4

75.8

73.3

73.1

69.4

54.8

70.9

63.9

74.0

78.3

86.5

88.6

78.3

97.6

92.0

87.7

92.9

75.1

75.7

94.3

93.2

100.0

82.3

59.1

75.1

89.9

92.0

82.9

78.5

100.0

82.9

54.8

83.2

22.5

21.8

21.7

21.4

34.5

24.4

34.1

25.1

17.8

11.5

8.2

21.7

 NA

8.0

11.0

6.0

24.0

24.3

5.7

6.8

0.0

16.7

40.9

22.5

10.1

8.0

15.5

17.8

40.9

13.2

0.0

15.0

1

Values less than minimum reporting levels were set to zero for the purpose of calculating percents and total DDT

2

Total DDT is the sum of residues of o,p’-DDT, p,p’-DDD, o,p’DDE, p,p’-DDT, p,p’-DDD, and p,p’-DDE

36 Concentrations of Selected Organochlorine Compounds in Fish Tissue in the MISE: AR, KY, LA, MS, MO, and TN, 1995-99
S.R. Femmer and others—Concentrations of Selected Organochlorine Compounds in Fish Tissue in the Mississippi Embayment Study Unit: —SIR 2004-5006

Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee, 1995-99

Printed on recycled paper