WATER-QUALITY ASSESSMENT OF THE 

ALBEMARLE-PAMLICO DRAINAGE 

BASIN, NORTH CAROLINA AND 

VIRGINIA A Summary of Selected Trace 

Element, Nutrient, and Pesticide Data for 

Bed Sediments, 1969-90

By Stanley C. Skrobialowski

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 96-4104

Raleigh, North Carolina 

1996
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

The use of firm, trade, and brand names in this report is for identification purposes 

only and does not constitute endorsement by the U.S. Geological Survey.

For additional information write to:

District Chief 

U.S. Geological Survey 

3916 Sunset Ridge Road 

Raleigh, NC 27607

Copies of this report can be purchased 

from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
FOREWORD

The mission of the U.S. Geological Survey 

(USGS) is to assess the quantity and quality of the 

earth resources of the Nation and to provide 

information that will assist resource managers and 

policymakers at Federal, State, and local levels in 

making sound decisions. Assessment of water-quality 

conditions and trends is an important part of this 

overall mission.

One of the greatest challenges faced by waterresources scientists is acquiring reliable information 

that will guide the use and protection of the Nation's 

water resources. That challenge is being addressed by 

Federal, State, interstate, and local water-resource 

agencies and by many academic institutions. These 

organizations are collecting water-quality data for a 

host of purposes that include compliance with permits 

and water-supply standards; development of 

remediation plans for a specific contamination 

problem; operational decisions on industrial, 

wastewater, or water-supply facilities; and research on 

factors that affect water quality. An additional need for 

water-quality information is to provide a basis on 

which regional and national-level policy decisions can 

be based. Wise decisions must be based on sound 

information. As a society we need to know whether 

certain types of water-quality problems are isolated or 

ubiquitous, whether there are significant differences in 

conditions among regions, whether the conditions are 

changing over time, and why these conditions change 

from place to place and over time. The information 

can be used to help determine the efficacy of existing 

water-quality policies and to help analysts determine 

the need for, and likely consequences, of new policies.

To address these needs, the Congress 

appropriated funds in 1986 for the USGS to begin a 

pilot program in seven project areas to develop and 

refine the National Water-Quality Assessment 

(NAWQA) Program. In 1991, the USGS began full 

implementation of the program. The NAWQA 

Program builds upon an existing base of water-quality 

studies of the USGS, as well as those of other Federal, 

State, and local agencies. The objectives of the 

NAWQA Program are to:

 Describe current water-quality conditions for 

a large part of the Nation's freshwater 

streams, rivers, and aquifers.

 Describe how water quality is changing over 

time.

 Improve understanding of the primary 

natural and human factors that affect waterquality conditions.

This information will help support the 

development and evaluation of management, 

regulatory, and monitoring decisions by other Federal, 

State, and local agencies to protect, use, and enhance 

water resources.

The goals of the NAWQA Program are being 

achieved through ongoing and proposed investigations 

of 60 of the Nation's most important river basins and 

aquifer systems, which are referred to as study units. 

These study units are distributed throughout the 

Nation and cover a diversity of hydrogeologic settings. 

More than two-thirds of the Nation's freshwater use 

occurs within the 60 study units and more than twothirds of the people served by public water-supply 

systems live within their boundaries.

National synthesis of data analysis, based on 

aggregation of comparable information obtained from 

the study units, is a major component of the program. 

This effort focuses on selected water-quality topics 

using nationally consistent information. Comparative 

studies will explain differences and similarities in 

observed water-quality conditions among study areas 

and will identify changes and trends and their causes. 

The first topics addressed by the national synthesis are 

pesticides, nutrients, volatile organic compounds, and 

aquatic biology. Discussions on these and other waterquality topics will be published in periodic summaries 

of the quality of the Nation's ground and surface water 

as the information becomes available.

This report is an element of the comprehensive 

body of information developed as part of the NAWQA 

Program. The program depends heavily on the advice, 

cooperation, and information from many Federal, 

State, interstate, Tribal, and local agencies and the 

public. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch 

Chief Hydrologist

Foreword III
IV
CONTENTS

Abstract.................................................................................................................................................................................. 1

Introduction........................................................................................................................................................................... 1

Purpose and scope ....................................................................................................................................................... 2

Acknowledgments....................................................................................................................................................... 2

Description of study unit............................................................................................................................................. 2

Factors influencing sediment quality........................................................................................................................... 4

Bed-sediment quality criteria and guidelines .............................................................................................................. 5

Data compilation.................................................................................................................................................................... 7

Data sources................................................................................................................................................................. 7

Data screening............................................................................................................................................................. 7

Metals and trace elements...................................................................................................................................................... 8

Aluminum.................................................................................................................................................................... 9

Arsenic......................................................................................................................................................................... 9

Beryllium..................................................................................................................................................................... 9

Cadmium..................................................................................................................................................................... 9

Chromium.................................................................................................................................................................... 10

Cobalt........................................................................................... 11

Copper......................................................................................................................................................................... 13

Iron............................................................................................................................................................................... 15

Lead................................................................. 15

Magnesium.................................................................................................................................................................. 16

Manganese.......................................................................................................................................................... ...... 17

Mercury....................................................................................................................................................................... 18

Nickel............................................................ 18

Selenium...................................................................................................................................................................... 18

Thallium............................................................................................ 20

Zmc... ............... ............................................ . . ..................... ..... .............. 20

Nutrients.........................................................................................................................~^ 21

Nitrite plus nitrate........................................................................................................................................................ 22

Ammonia..................................................................................................................................................................... 22

Ammonia plus organic nitrogen .................................................................................................................................. 22

Total phosphorus and orthophosphorus....................................................................................................................... 23

Pesticides and PCB's............................................................................................................................................................. 24

Aldrin............................................................... ^ 25

Atrazine....................................................................................................................................................................... 25

Chlordane..................................................................................................................................................................... 26

ODD. ......................... ....................... . .... . .... ..... .... .................. . . 26

DDE.................................................................» 27

DDT............................................................................................................................................................................. 27

Dieldrin... . ................................. ... ........................... . ................... ^ 29

Endrin.......................................................................................................................................................................... 30

Heptachlor................................................................................................................................................................... 30

Toxaphene.................................................................................................................................................................... 31

PCB's.................................................................^ 31

Summary and conclusions..................................................................................................................................................... 31

Selected references................................................................................................................................................................ 32

Contents
FIGURES

1-3. Maps showing:

1. Location of the Albemarle-Pamlico study unit and physiographic provinces in the study area,

North Carolina and Virginia........................................................................................................................... 3

2. Maximum arsenic concentrations detected in bed sediment from major river basins

in the Albemarle-Pamlico study unit, 1969-90............................................................................................... 10

3. Maximum cadmium concentrations detected in bed sediment from major river basins in the

Albemarle-Pamlico study unit, 1969-90........................................................................................................ 11

4. Box plots of maximum total chromium, copper, lead, mercury, nickel, and zinc concentrations detected

in bed sediment from major river basins in the Albemarle-Pamlico study unit, 1969-90...................................... 12

5-19. Maps showing maximum concentrations detected in bed sediment from major river basins in the 

Albemarle-Pamlico study unit, 1969-90:

5. Chromium.......................................................................................................................................................... 13

6. Copper............................................................................................................................................................... 14

7. Iron .................................................................................................................................................................... 15

8. Lead.......................................................................................................................................^ 16

9. Manganese......................................................................................................................................................... 17

10. Mercury............................................................................................................................................................. 19

11. Nickel................................................................................................................................................................ 20

12. Zinc...................................................................................................................................................................^ 21

13. Ammonia plus organic nitrogen........................................................................................................................ 23

14. Phosphorus........................................................................................................................................................ 24

15. Chlordane.......................................................................................................................................................... 26

16. ODD.................................................................................................................................................................. 27

17. DDE................................................................................................................................................................... 28

18. DDT................................................................................................................................................................... 29

19. Dieldrin.............................................................^ 30

TABLES

1. Guidelines for concentrations of selected trace element and nutrients in bed sediments

of the Albemarle-Pamlico study unit................................................................................................................... 5

2. Guidelines for concentrations of selected pesticides and PCB's in bed sediments of the

Albemarle-Pamlico study unit............................................................................................................................. 6

3. Occurrence of selected trace elements in bed sediments of the Albemarle-Pamlico study unit, 1969-90............. 8

4. Occurrence of selected nutrients in bed sediments of the Albemarle-Pamlico study unit, 1969-90...................... 22

5. Occurrence of selected pesticides and PCB's in bed sediments of the Albemarle-Pamlico study unit,

1969-90................................................................................................................................................................ 25

VI Contents
WATER-QUALITY ASSESSMENT OF THE 

ALBEMARLE-PAMLICO DRAINAGE BASIN, 

NORTH CAROLINA AND VIRGINIA A Summary 

of Selected Trace Element, Nutrient, and Pesticide 

Data for Bed Sediments, 1969-90

By Stanley C. Skrobialowski

ABSTRACT

Spatial distributions of metals and trace 

elements, nutrients, and pesticides and 

poly chlorinated biphenyls (PCB's) in bed 

sediment were characterized using data collected 

from 1969 through 1990 and stored in the U.S. 

Geological Survey's National Water Data Storage 

and Retrieval (WATSTORE) system and the U.S. 

Environmental Protection Agency's Storage and 

Retrieval (STORET) system databases. Bedsediment data from WATSTORE and STORET 

were combined to form a single database of 1,049 

records representing 301 sites. Data were 

examined for concentrations of 16 metals and 

trace elements, 4 nutrients, 10 pesticides, and 

PCB's. Maximum bed-sediment concentrations 

were evaluated relative to sediment-quality 

guidelines developed by the National Oceanic and 

Atmospheric Administration, the Ontario 

Ministry of Environment and Energy, and the 

Virginia Department of Environmental Quality.

Sites were not selected randomly; therefore, 

results should not be interpreted as representing 

average conditions. Many sites were located in or 

around lakes and reservoirs, urban areas, and 

areas where special investigations were 

conducted. Lakes and reservoirs function as 

effective sediment traps, and elevated 

concentrations of some constituents occurred at

these sites. High concentrations of many metals 

and trace elements also occurred near urban areas 

where streams receive runoff or inputs from 

industrial, residential, and municipal activities. 

Elevated nutrient concentrations occurred near 

lakes, reservoirs, and the mouths of major rivers.

The highest concentrations of arsenic, 

beryllium, chromium, iron, mercury, nickel, and 

selenium occurred in the Roanoke River Basin 

and may be a result of geologic formations or 

accumulations of bed sediment in lakes and 

reservoirs. The highest concentrations of 

cadmium, lead, and thallium were detected in the 

Chowan River Basin; copper and zinc were 

reported highest in the Neuse River Basin. Total 

phosphorus and total ammonia plus organic 

nitrogen concentrations exceeded the sediment 

evaluation guidelines in each major river basin, 

possibly resulting from wastewater inputs and 

agricultural applications. Exceedances of 

pesticide guidelines were detected in the upper 

Neuse River Basin near Falls Lake and in the 

lower Tar River Basin.

INTRODUCTION

In 1991, the U.S. Geological Survey (USGS) 

implemented the National Water-Quality Assessment 

(NAWQA) Program. When fully implemented, the

Abstract 1
NAWQA Program will include a total of about 60 

study units that incorporate about 60 to 70 percent of 

the Nation's water use and population served by public 

water supply (Leahy and others, 1990). Long-range 

goals of the NAWQA Program are to describe the 

status and trends in the quality of a substantial part of 

the Nation's surface- and ground-water resources and 

to better understand factors that influence water 

quality. In meeting these goals, the program will 

produce surface-water, ground-water, and ecological 

data that will be useful to policy makers and resource 

managers at the national, State, and local levels.

The Albemarle-Pamlico study unit (fig. 1) was 

among the first 20 NAWQA study units that began in 

1991. As part of the study, data previously collected in 

the study unit were analyzed to evaluate historical 

conditions and to guide new data collection. Between 

1969 and 1990 more than 1,000 bed-sediment samples 

were collected by various agencies throughout the 

Albemarle-Pamlico study unit and were analyzed for 

numerous metals and trace elements, nutrients, and 

organic contaminants. Results were stored in national 

databases, including the U.S. Geological Survey's 

National Water Data Storage and Retrieval 

(WATSTORE) system and the U.S. Environmental 

Protection Agency's (U.S. EPA) Storage and Retrieval 

(STORET) system databases.

Bed sediments may be sinks or sources of 

metals and trace elements, nutrients, or organic 

contaminants and, thus, are an important component 

of the aquatic environment. Concentrations of metals 

and trace elements and toxic substances in bed 

sediment can exceed those of overlying waters by 

several orders of magnitude (Horowitz, 1991). 

Elevated concentrations of metals and trace elements 

in bed sediment may occur naturally from the local 

geology. Anthropogenic sources of some metals and 

trace elements and toxic materials are associated with 

industrial and densely populated urban areas, whereas 

other sources may be associated with agricultural 

activities and sparsely populated rural areas. 

Organisms dwelling or feeding in or near bed 

sediments provide a pathway for introducing 

contaminants to the food web (Hem, 1985; Horowitz, 

1991).

Purpose and Scope

This report presents summary statistics for 

selected bed-sediment data in the WATSTORE and

STORET databases and provides a synoptic spatial 

representation of detected and elevated values for 

selected metals and trace elements, nutrients, 

pesticides and polychlorinated biphenyls (PCB's). 

Although the identification of specific sources of 

elevated concentrations is beyond the scope of this 

investigation, some conclusions about elevated 

concentrations are discussed with respect to land uses 

and other features that may affect the presence of these 

concentrations.

Data from October 1969 through August 1990 

were compiled for the Albemarle-Pamlico study unit 

in North Carolina and Virginia, excluding the 

estuaries. Data from WATSTORE and STORET were 

combined to form one resultant database consisting of 

1,049 records from 301 sites. Data retrieved from 

WATSTORE consisted of 139 samples collected at 31 

sites by the USGS in cooperation with other local, 

State, and Federal agencies. Data from STORET 

included 910 records representing 270 sites and were 

collected primarily by the North Carolina Division of 

Environmental Management (NCDEM) of the 

Department of Environment, Health, and Natural 

Resources and the Virginia Department of 

Environmental Quality (VADEQ) (formerly the 

Virginia Water Control Board). These data were 

compared with various sediment-quality guidelines 

and are presented as tabulated statistics. Maximum 

detected concentrations of some constituents were 

compared with guidelines and are presented in 

boxplots or maps.

Acknowledgments

The author gratefully acknowledges the 

agencies that contributed to the WATSTORE and 

STORET databases, especially the North Carolina 

Department of Environment, Health, and Natural 

Resources and the Virginia Department of 

Environmental Quality. Douglas A. Harned of the 

USGS provided guidance and data analysis, and 

reviewed early drafts of this report.

Description of Study Unit

The Albemarle-Pamlico study unit is located in 

southeastern Virginia and northeastern North Carolina 

and drains an area of about 28,000 square miles. It 

consists of four major river basins the Roanoke,

Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Appalachian 

Plateaus

« ' NORTH CAROLINA - ,' I K^

Piedmont /

LOCATION OF STUDY AREA AND PHYSIOGRAPHIC PROVINCES

IN NORTH CAROLINA AND VIRGINIA

(Modified from Fenneman, 1938)

...... Roanoke

BlacksburgT"

*/ '/" Smith MrnVk!^ ' 

r,- (_ . Lake *V ^v.

EXPLANATION 

 DRAINAGE AREA BOUNDARY

Figure 1 . Location of the Albemarle-Pamlico study unit and physiographic provinces in the study area, North Carolina and 

Virginia.

Introduction 3
Chowan, Tar, and Neuse Rivers and many smaller 

drainage basins located around estuaries. In this 

report, the Chowan River Basin includes the area 

drained by the Chowan River, tributaries of the 

Chowan River, and several smaller basins located 

around Albemarle Sound as shown in figure 1.

The study unit includes parts of the Valley and 

Ridge, Blue Ridge, Piedmont, and Coastal Plain 

physiographic provinces. The Roanoke River Basin 

drains a portion of each physiographic province, and 

the Chowan, Tar, and Neuse River Basins drain parts 

of the Piedmont and Coastal Plain Provinces.

The Albemarle-Pamlico study unit is about 50 

percent forested, 30 percent agriculture, 15 percent 

wetland, and 5 percent developed. The Roanoke River 

Basin, the largest of the four river basins, has the most 

forested land, and the Tar and Neuse River Basins 

have the largest percentages of agricultural land. The 

largest area of wetlands is located in and around the 

sounds and the lower reaches of rivers in the eastern 

part of the study unit. The Neuse River Basin has the 

largest percentage of developed land (McMahon and 

Lloyd, 1995).

Factors Influencing Sediment Quality

Natural and anthropogenic factors influence 

bed-sediment quality within each basin. Natural 

factors include type, grain size, weathering, and 

hydrologic conditions. Anthropogenic factors include 

agriculture, mining, construction, and land and lumber 

clearing.

The Valley and Ridge, Blue Ridge, Piedmont, 

and Coastal Plain have different geologic 

characteristics because different combinations of rock 

types underlie each province (McMahon and Lloyd, 

1995). These different rock types are the parent 

material for soils, and suspended and bed sediments in 

the study unit.

Each of the major river basins drains some parts 

of the inner and outer Coastal Plain and areas 

underlain by granitic and slate belt rocks and 

unconsolidated sediments of the Coastal Plain. The 

headwaters of the Neuse and Tar Rivers and mainstem 

of the Roanoke River drain areas underlain by Triassic 

rocks. The headwaters of the Roanoke River drain 

parts of the Valley and Ridge that contain consolidated 

sedimentary rocks, and the Neuse River drains Coastal 

Plain unconsolidated rocks. Many of the carbonate 

rocks of the Coastal Plain are buried, and some local

shell hash beds may occur along bluffs of the Roanoke 

and Meherrin Rivers.

Weathering causes parent rock material to break 

down, resulting in dissolved material or solid particles 

small enough to be transported by streams and rivers. 

As the grain size of sediment particles decreases, the 

ratio of total surface area to the volume of particles 

increases. High concentrations of metals and trace 

elements are usually associated with fine-grained 

sediments (Horowitz, 1991).

Hydrologic conditions influence bed-sediment 

quality. During periods of high flow, increased 

discharge velocities can cause bed sediments to 

become suspended and be transported downstream. As 

velocities decrease to the point where particles no 

longer remain suspended, sediments may settle on the 

streambed or continue to move along the streambed as 

bed load. This transport of suspended and resettled 

particles increases the exposure of sediment to 

different water-quality conditions.

Sediment particles exposed to different waterquality conditions undergo changes in physical or 

chemical characteristics. Some of the water-quality 

characteristics that influence bed-sediment quality 

include pH, temperature, dissolved oxygen, and 

oxidation reduction potential (Horowitz, 1991).

Reservoirs and wetlands act as traps for 

suspended sediments. Fine-grained sediment particles 

are commonly associated with lakes and reservoirs 

because smaller grain-size fractions require lower 

stream velocities to settle. Belews Lake, Philpott Lake, 

Smith Mountain Lake, Kerr Lake, and Lake Gaston 

are reservoirs within the Roanoke River Basin and trap 

sediment from parts of the Valley and Ridge, and 

Piedmont (fig. 1). Falls Lake Reservoir near Raleigh 

and Durham, N.C., impounds the Neuse River. Several 

smaller lakes and reservoirs also are located in the 

Albemarle-Pamlico drainage study unit.

The Albemarle-Pamlico study unit has a 

population of about 3 million people (McMahon and 

Lloyd, 1995). Principal urban areas include Eden, 

Goldsboro, Greenville, Kinston, Raleigh, Roanoke 

Rapids, and Wilson, and outlying urban areas of 

Durham and Winston-Salem, N.C., and Danville, 

Franklin, Roanoke, and suburban areas of Blacksburg, 

Chesapeake, Petersburg, and Virginia Beach, Va. 

(fig. 1). Urban land-use factors influence sediment 

quality by introducing contaminants from sewage and 

industrial wastewater inputs as well as by activities 

associated with residential areas, and commercial, 

municipal, industrial, and transportation facilities.

Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Agricultural activities influence bed-sediment 

quality as a result of water-control structures, soil 

conservation practices, types of crops or livestock 

produced, and applications of fertilizers and 

pesticides. Agricultural land in the study unit is used 

for the production of crops such as corn, soybeans, 

cotton, peanuts, tobacco, and wheat, as well as 

livestock that include poultry, swine, and cattle. 

Generally, more agricultural activity occurs in the Tar 

and Neuse River Basins than in the Chowan or 

Roanoke River Basins (McMahon and Lloyd, 1995).

Bed-Sediment Quality Criteria and 

Guidelines

Currently, the U.S. ERA has established bedsediment quality criteria for a few pesticides in 

sediments. The U.S. ERA dratted Sediment Quality 

Criteria (SQC) for some pesticides using an

equilibrium partitioning approach (Nowell and Resek, 

1994). These criteria were not used to evaluate data for 

this report because organic carbon concentrations are 

needed to properly apply them, and relatively little 

organic carbon data are available for bed sediment. A 

detailed explanation of sediment classification 

methods is given by the U.S. Environmental 

Protection Agency (1992). There are no State or 

Federal criteria for metals and trace elements or 

nutrients in sediments.

The National Oceanic and Atmospheric 

Administration (NOAA), the Ontario Ministry of 

Environment and Energy (OMEE), and VADEQ 

developed guidelines to evaluate bed-sediment data. 

Selected guidelines developed by these agencies are 

used in this report to evaluate concentrations of metals 

and trace elements, and nutrients (table 1). Guidelines 

developed by NOAA and OMEE are used to evaluate

Table 1 . Guidelines for concentrations of selected trace elements and nutrients in bed sediments, in parts per million, 

of the Albemarle-Pamlico study unit

[NOAA, National Oceanic and Atmospheric Administration: Effects range-low Concentrations above which biological effects are observed or predicted 

to begin (10th percentile). Effects range-median Concentrations above which adverse biological effects were frequently or always observed or predicted 

(50th percentile). OMEE, Ontario Ministry of Environment and Energy: Background Values are based on analyses of Great Lakes pre-colonial sediment 

horizon. Lowest effect level Value indicates a level of sediment contamination that can be tolerated by the majority of benthic organisms. Severe effect 

level Sediment concentration of a constituent that would be detrimental to the majority of benthic organisms. VADEQ, Virginia Department of 

Environmental Quality: Background 85th percentile of data ranked. Index of potential contamination Concentrations in fish tissue are to be measured 

when bed-sediment concentrations equal or exceed this level. High- -95th percentile of data collected and ranked. Values shown in bold are used as evaluation 

guidelines in this report. , not available]

NOAA3

Constituent

Arsenic

Beryllium

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Mercury

Nickel

Zinc

Ammonia + 

total nitrogen

Total phosphorus

Effects 

range-low

33

5

80

70

35

.15

30

120

Effects 

rangemedian

85

9

145

390

110

1.3

50

270

Background

4.2

1.1

31

25

31,200

23

400

.10

31

65

OMEEb

Lowest 

effect 

level

6

.6

26

16

20,000

31

460

.2

16

120

550

600

Severe 

effect 

level

33

to

110

110

40,000

250

1,100

2

75

820

4,800

2,000

VADEQC

Index of 

Back- potential 

ground contamina- 3 

tion

14.8 21.0

 2.1

.63 2.3

 

44 95.2

 

78 178

 

 0.3 

 

 

 

 

aLong and Morgan, 1991. 

bPersaud and others, 1993. 

cTigler and others, 1990.

Bed-Sediment Quality Criteria and Guidelines
concentrations of selected pesticides and PCB's 

(table 2).

Table 2. Guidelines for concentrations of selected 

pesticides and PCB's in bed sediments, in parts per billion, 

of the Albemarle-Pamlico study unit

[NOAA, National Oceanic and Atmospheric Administration: Effects 

range-low Concentrations above which biological effects are observed or 

predicted to begin (1 Oth percentile). Effects range-median 

Concentrations above which adverse biological effects were frequently or 

always observed or predicted (50th percentile). OMEE, Ontario Ministry 

of Environment and Energy: Lowest effect level Value indicates a level 

of sediment contamination that can be tolerated by the majority of benthic 

organisms. Values shown in bold are used as evaluation guidelines in this 

report. , not available]

Pesticide/ - 

PCB's

Aldrin

Chlordane

ODD

DDE

DDT

Dieldrin

Endrin

PCB's

Effects 

range-low

0.5

2

2

1

.02

.02

50

NOAAa

Effects rangemedian

6

20

15

7

8

45

400

OMEEb

Lowest 

effect level

2

7

8

5

8

2

3

70

aLong and Morgan, 1991. 

bPersaud and others, 1993.

The guidelines used to evaluate data for this 

report (tables 1 and 2) are effects-threshold 

concentrations for selected metals and trace elements, 

pesticides, and PCB's from NOAA (Long and 

Morgan. 1991). When NOAA guidelines were not 

available, the Provincial Sediment Quality Guidelines 

determined by OMEE for selected metals, trace 

elements, and nutrients were used (Persaud and others, 

1993). Mercury data also were compared with the 

index developed by VADEQ (Tigler and others, 1990).

Long and Morgan (1991) developed guidelines 

called "effects range thresholds" for NOAA to use in 

assessing potential adverse effects on biota from 

exposure to toxics in sediments. They reviewed 

approximately 85 studies that linked biological effects 

with measured concentrations of metals and trace 

elements, pesticides, and other organic compounds in 

bed sediments. Analyte concentrations were ranked to 

determine effects range-low (ER-L) and effects rangemedian (ER-M). The lower I Oth percentile of each 

constituent was identified as the ER-L value. Sediment 

concentrations at the ER-L were associated with 

adverse biological effects on some benthic organisms. 

Adverse biological effects were frequently or always 

observed or predicted at the ER-M concentration (the 

50th percentile). Although these ER-L and ER-M 

values may be used as guidelines for evaluating 

sediment contamination data, they were not intended 

to be regulatory standards or criteria (Long and 

Morgan, 1991). Effects range thresholds were used to 

evaluate selected constituents in this report (tables 1 

and 2).

Sediment-quality guidelines determined by 

OMEE include background and effects threshold 

concentrations for selected metals and trace elements, 

nutrients, and pesticides and other organic compounds 

(tables 1 and 2). Background concentrations were 

"based on analyses of Great Lakes pre-colonial 

sediment horizon" and represent a level of acceptable 

contamination (Persaud and others, 1993). 

Concentrations below the lowest effect level have little 

or no biological effect on the majority of benthic 

organisms. Sediment concentrations at the severe 

effect level are expected to harm benthic organisms. 

According to Persaud and others (1993), some of these 

threshold concentrations are similar to those 

developed by Long and Morgan (1991) for NOAA. 

However, all thresholds may not be similar because 

different reports and data were used by each group.

Tigler and others (1990) reviewed STORET 

data for VADEQ for sediment-borne toxicants. These 

data were collected over a 20-year period for an 

"Ambient Water Quality Monitoring Network." A 

frequency distribution for each constituent was 

produced, and the 85th percentile was identified as the 

background concentration for each constituent. Values 

at or above the 95th percentile were considered 

elevated and warranted further investigation. 

Background and elevated concentrations were 

determined for arsenic, beryllium, lead, cadmium, and 

copper (table 1). Also, VADEQ established an index of 

potential mercury contamination in freshwater 

sediment, and requires that methylmercury 

concentrations in fish tissue be measured when 

mercury in bed sediments exceeds the index 

concentration of 0.3 parts per million (ppm) (Tigler 

and others, 1990).

Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
DATA COMPILATION Data Sources

It is acknowledged that different methods of 

collection, processing, and analysis may have been 

used among the respective collecting agencies, and 

these differences may contribute to the variability of 

the data. Sample collection and processing procedures 

were not always well documented. A detailed 

description of USGS methods and processing 

procedures is given by Edwards and Glysson (1988), 

Ward and Harr (1990), Horowitz (1991), and Shelton 

and Capel( 1994).

Sediment is sometimes sieved to separate the 

fine-grained (less than 63 micron) fraction for 

chemical analysis because this fraction often contains 

higher metal and trace element concentrations 

(Horowitz and Elrick, 1988; Horowitz and others, 

1989; Horowitz, 1991). Sediment samples collected 

by NCDEM and VADEQ were not sieved (Jay Sauber, 

NCDEM, oral commun., 1995; Ron Gregory, VADEQ, 

oral commun., 1995). Samples collected by the USGS 

were sieved to 2.00 millimeters. USGS samples that 

were known to have been sieved to include only the 

fine-grained fraction were not included in this analysis 

so that data from the two sources would be more 

comparable (Horowitz and Elrick, 1988; Horowitz and 

others, 1989; Horowitz, 1991).

Similar laboratory methods were used to 

analyze samples collected by the NCDEM, USGS, 

and VADEQ. However, analytical methods used by 

other collecting agencies are not well documented and 

may be different from those used by the NCDEM, 

USGS, and VADEQ. Extraction or atomic absorption 

or emission spectrometry methods were used to 

determine metal and trace element concentrations 

collected by the USGS, NCDEM, and VADEQ 

according to Fishman and others (1994), Jay Sauber 

(NCDEM, oral commun., 1995), and Charles Morgan 

(VADEQ, oral commun., 1996). The NCDEM and 

USGS used colorimetry methods to determine nutrient 

concentrations (Fishman and others, 1994; Jay Sauber, 

NCDEM, oral commun., 1996). Gas chromatography 

methods were used to determine pesticide 

concentrations in bed sediment collected by the 

NCDEM, USGS, and VADEQ (Fishman and others, 

1994; Ray Kelling, NCDEM, oral commun., 1996; 

Charles Morgan, VADEQ, oral commun., 1996).

Bed-sediment data were retrieved from 

WATSTORE and STORET databases. The data 

retrieved from WATSTORE initially yielded 200 

records from 52 sites. These data were collected 

between August 1973 and June 1990 by the USGS in 

cooperation with other Federal, State, and local 

agencies. The STORET database serves as the primary 

water-resources data repository for contributors from 

Federal, State, and local agencies, as well as for 

research interests from colleges, universities, and 

industry. Data retrieved from STORET for this report 

initially yielded 913 records. The STORET bedsediment samples were collected primarily by 

NCDEM and VADEQ between October 1969 and 

August 1990 at 272 sites.

Samples were collected from sites in all major 

river basins, physiographic regions, and land-use types 

in the study unit; however, sites were not selected 

randomly. In general, sampling sites were clustered 

around urban areas, reservoirs, or in other areas where 

special investigations were being conducted. Some 

sites belonged to ambient monitoring networks, 

whereas others were located in areas of known or 

suspected contamination.

Data Screening

Initial data retrieved from WATSTORE and 

STORET were combined to form one database 

consisting of 1,113 records from a total of 324 sites. 

Many values were reported as concentrations less than 

some detection limit. However, only values that 

appeared to be entered erroneously and those 

associated with a remark code indicating "presumptive 

evidence of presence of material" were deleted. The 

resulting database consisted of a total of 1,049 records 

from301 sites for 16 metals and trace elements 

aluminum, arsenic, beryllium, cadmium, chromium, 

cobalt, copper, iron, lead, magnesium, manganese, 

mercury, nickel, selenium, thallium, and zinc; 5 

nutrients nitrite plus nitrate, ammonia, total 

ammonia plus organic nitrogen, orthophosphorus, and 

total phosphorus; 10 pesticides aldrin, atrazine, 

chlordane, DDD, DDE, DDT, dieldrin, endrin, 

heptachlor, and toxaphene; and PCB's.

Data Compilation
METALS AND TRACE ELEMENTS

Small quantities of many metals and trace 

elements are necessary for normal plant and animal 

growth and development. However, even small 

concentrations of some metals and trace elements such 

as mercury and thallium may be detrimental to plant 

and animal life.

Statistics for aluminum, arsenic, beryllium, 

cadmium, chromium, cobalt, copper, iron, lead, 

magnesium, manganese, mercury, nickel, selenium, 

thallium, and zinc in bed sediment are presented in

this report (table 3). Metal and trace element concentrations were evaluated with guidelines determined by 

NOAA, OMEE, and VADEQ (table 1). The most 

frequently sampled metals and trace elements were 

arsenic, cadmium, chromium, copper, lead, mercury, 

nickel, and zinc. Aluminum, beryllium, cobalt, 

magnesium, and thallium were sampled less 

frequently (table 3). Aluminum, chromium, copper, 

iron, lead, magnesium, manganese, nickel, and zinc 

were detected in more than 80 percent of the samples 

and at more than 80 percent of the sites. Beryllium, 

cadmium, and thallium were detected in less than

Table 3. Occurrence of selected trace elements in bed sediments of the Albemarle-Pamlico study unit, 1969-90 

[ppm, parts per million; , not available]

Trace 

element

Aluminum

Arsenic

Beryllium

Cadmium

Chromium

Cobalt

Copper

Iron

Lead

Magnesium

Manganese

Mercury

Nickel

Selenium

Thallium

Zinc

Number 

of 

samples

62

646

64

632

667

56

694

174

696

84

192

568

564

238

63

684

Number 

of 

sites 

sampled

48

254

33

239

244

32

248

75

249

49

95

257

224

90

33

249

Percentage 

of 

samples 

with 

detected 

concentrations

100

56.6

25

20.6

93.2

44.6

89.6

99.4

88.2

100

99.5

51.6

92.9

65.1

22.2

99.9

Percentage 

of sites 

with 

detected 

concentrations

100

62.6

36.4

39.7

94.3

53

93.5

100

95.6

100

98.9

57.6

87.0

74.4

27.3

99.2

Range of 

detected 

concentrations (ppm)

640-47,000

0.00196-67

0.07-2.8

0.11-3.2

0.6-3,700

0.049-24

0.03-1,900

8.4-67.600

0.008-687

0.19-11,800

0.34-24,000

0.01-47

0.58-2,000

0.2-24

1.3-8.8

0.0043-950

Evaluation 

guideline 

(ppm)

33a

2.1b

15

80"

70a

20.000P

35a

460°

.15a

30"

120"

Percentage of 

samples 

with 

concentrations 

greater 

than 

evaluation

guideline

0.6

3.1

0

2.7

2.3

16.7

17

38

13.6

13.3

13.2

Percentage of 

sites with 

concentrations 

greater 

than 

evaluation

guideline

1.6

3.0

0

4.5

4.4

30.7

27.3

53.7

23.3

12.9

19.7

aLong and Morgan, 1991. 

bTigler and others, 1990. 

cPersaud and others, 1993.

8 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
40 percent of the samples and at less than 40 percent 

of the sites. The percentage of guideline exceedances 

was less than 10 percent for arsenic, beryllium, 

cadmium, chromium, and copper; whereas, 

exceedances were higher for iron, lead, mercury, 

nickel, and zinc (table 3).

Maximum detected concentrations of metals 

and trace elements are reported in parts per million for 

each site and are presented in boxplots and maps. 

Many metals and trace elements had multiple 

detection limits; therefore, screening thresholds were 

established for constituents shown in boxplots. The 

screening threshold for each constituent is equivalent 

to the highest or one of the highest detection limits. 

For statistical analysis, concentrations reported below 

the screening threshold were substituted with the value 

of the screening threshold. Therefore, the lower 

portion of some boxes may be masked by the 

screening threshold. In cases where the screening 

threshold was set higher than many detected 

concentrations (those above other detection limits), a 

lower screening threshold value was substituted in the 

database. Concentrations reported below the detection 

limit and above the new lower screening threshold 

were omitted from the illustration. Where data are 

sufficient, boxplots are provided for constituents that 

are designated as Priority Pollutants by the U.S. 

Environmental Protection Agency (1994).

Aluminum

Aluminum is one of the most abundant metals in 

the Earth's crust and is considered to be nontoxic. It is 

used in manufacturing and industry and for kitchen 

utensils, auto parts, beverage containers, and 

aluminum wires and lines (Weast, 1983). Natural 

sources of aluminum are many silicate minerals in 

igneous rocks and clay minerals in common 

sedimentary aluminum-enriched deposits (Hem, 

1985). Sources of aluminum in bed sediment in the 

study unit are probably natural, given the relative 

abundance of naturally occurring aluminum and clay 

deposits.

Aluminum was detected in all 62 samples that 

were collected at 48 sites. Detected aluminum 

concentrations ranged from 640 to 47,000 ppm 

(table 3). There are no current guidelines with which 

to evaluate aluminum concentrations in bed sediment.

Arsenic

Arsenic is a trace element that is among the U.S. 

EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994). It is used in 

bronze, fireworks, pesticides, transistors, "salt-treated" 

lumber, and in manufacturing shot (Weast, 1983). 

Arsenic may occur in coal and in some ores and 

phosphate rocks (Hem, 1985).

Arsenic was detected in nearly 57 percent of 

646 samples. Arsenic concentrations were detected at 

almost 63 percent of 254 sites sampled (table 3).

The highest detected arsenic concentration of 

67 ppm occurred in the Roanoke River Basin. The 

guidelines used in this report to evaluate arsenic 

concentrations are the ER-L and ER-M determined by 

Long and Morgan (1991). Detected arsenic 

concentrations exceeded the ER-L in 0.6 percent of 

the samples collected and at 1.6 percent of the sites 

sampled. Three sites where ER-L exceedances occur 

are located at or near lakes or reservoirs, and one site 

is located on the mainstem of the Roanoke River 

(fig. 2). Most concentrations that exceeded the ER-L 

were in the Roanoke River Basin. There were no 

arsenic exceedances of the ER-M.

Beryllium

Beryllium is a trace element and occurs in 

several minerals and in some precious stones, such as 

emerald and aquamarine. Beryllium is one of the 

lightest of all metals and is used for springs, electrical 

contacts, spot-welding electrodes, and nonsparking 

tools (Weast, 1983).

Beryllium was detected in 25 percent of 64 

samples collected. Beryllium concentrations were 

detected at about 36 percent of 33 sites sampled 

(table 3).

The evaluation guideline used in this report for 

beryllium was 2.1 ppm; VADEQ considers beryllium 

concentrations above 2.1 ppm to be elevated. One site 

at Philpott Lake (fig. 1) had beryllium concentrations 

above 2.1 ppm. There were no other detected 

exceedances of the guideline for beryllium.

Cadmium

Cadmium is a toxic trace element that often 

occurs with zinc, copper, and lead ores. Electroplating,

Metals and Trace Elements
80° 79° 78° 77° 76°

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EXPLANATION 7. 

 - BASIN BOUNDARY ^~

o ARSENIC CONCENTRATION LESS THAN OR 

EQUAL TO 33 PARTS PER MILLION (table 1)

 ARSENIC CONCENTRATION GREATER THAN 33 PARTS 

PER MILLION AND LESS THAN OR EQUAL TO 85 PARTS 

PER MILLION (table 1)

cP

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 2. Maximum arsenic concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

solder, batteries, and pigments are among its many 

uses (Weast, 1983). Cadmium is on the U.S. EPA's list 

of 126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994).

Cadmium was detected in nearly 21 percent of 

632 samples collected at 239 sites. Cadmium 

concentrations were detected at nearly 40 percent of 

the sites and ranged from 0.11 to 3.2 ppm (table 3; 

fig- 3).

The guideline used in this report to evaluate 

cadmium concentrations was the ER-L of 5 ppm from 

Long and Morgan (1991) (table 1). There were no 

cadmium exceedances of the guideline reported in the 

data.

Chromium

Chromium is a toxic trace element that occurs 

more commonly in ultramafic rocks than in other rock 

types (Hem, 1985). Chromium is on the U.S. EPA's 

list of 126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994). It is used in steel 

production, for plating and leather tanning, to prevent 

corrosion, and to color glass and textiles (Weast, 

1983).

Chromium was detected in approximately 93 

percent of 667 samples collected and occurred at 

about 94 percent of the sites sampled (table 3). 

Chromium concentrations were highest in the

10 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
80° 79° 78° 77° 76°

37°

36°

35C

&<& a ° ;\..-/ V""

^ N "--x ° 

EXPLANATION

 - BASIN BOUNDARY

o CADMIUM CONCENTRATION LESS THAN OR 

EQUAL TO 5 PARTS PER MILLION (table 1)

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Alters equal area projection

Figure 3. Maximum cadmium concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

Roanoke River Basin (fig. 4). The guidelines used in 

this report to evaluate chromium concentrations were 

the ER-L of 80 ppm and the ER-M of 145 ppm (table 

1), and the screening threshold was 10 ppm. 

Chromium concentrations exceeded the ER-L in 

nearly 3 percent of the samples collected and at 4.5 

percent of the sites sampled. Ten sites where 

concentrations exceeded the ER-L are located in the 

Roanoke River Basin, nine of which are on or near 

lakes or reservoirs (fig. 5). The ER-M was exceeded at 

one site in the Tar River Basin (3,700 ppm); however, 

because this value is an extreme outlier and there are 

no suspected sources of chromium nearby, the source 

of this concentration is unknown. The second highest 

value, 107 ppm, was reported at Philpott Lake in the 

upper Roanoke River Basin, and the highest median

concentration occurred in the Roanoke River Basin 

(fig. 4).

Cobalt

Cobalt is a trace element that occurs in crustal 

igneous rocks (Hem, 1985). Cobalt alloys are used for 

cutting tools, dies, magnet steels, stainless steel, jet 

turbines, and gas turbine generators. Cobalt 

compounds are used for coloring porcelain, glass, 

pottery, tiles, and enamel. Trace amounts of cobalt are 

important for proper animal nutrition (Weast, 1983).

Cobalt was detected in about 45 percent of 56 

samples collected at 32 sites. Cobalt was detected at 

53 percent of the sites sampled. Detected

Cobalt 11
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12 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
80° 79° 78° 77° 76°

37°

/ *

o

-f-O- -°-

X

36°

35°

'V.

North Carolina " *..

0 50 100 MILES

r

0 50 100 KILOMETERS

EXPLANATION '-7 

 - - BASIN BOUNDARY '*- . N

O CHROMIUM CONCENTRATION LESS THAN OR 

EQUAL TO 80 PARTS PER MILLION (table 1)

 CHROMIUM CONCENTRATION GREATER THAN 

80 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 145 PARTS PER MILLION (table 1)

 CHROMIUM CONCENTRATION GREATER THAN 

145 PARTS PER MILLION (table 1)

I_________________]____________

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 5. Maximum chromium concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

concentrations ranged from 0.049 to 24 ppm (table 3). 

There are no current guidelines with which to evaluate 

cobalt concentrations in bed sediment.

Copper

Copper is a trace element that is included on the 

U.S. EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994). It is used 

extensively by the electrical industry. Copper also is 

used in algicides and insecticides (Weast, 1983).

Copper was detected in almost 90 percent of 

694 samples collected at 248 sites. Copper was 

detected in about 94 percent of the sites sampled. 

More exceedances occurred in the Roanoke River 

Basin than in the Neuse or Tar River Basins (fig. 4).

The guidelines used for copper in this report were the 

ER-L of 70 ppm and the ER-M of 390 ppm (table 1), 

and the screening threshold was 10 ppm. The ER-L 

was exceeded in about 2 percent of the samples and at 

about 4 percent of the sites where samples were 

collected (table 3). Copper concentrations exceeded 

the ER-L at seven sites in the Roanoke River Basin, 

one site in the Tar River Basin, and one site in the 

Chowan River Basin (fig. 6). All ER-L exceedances 

were located on or near a lake or reservoir or an urban 

area. The highest median concentration occurred in 

the Roanoke River Basin.

The ER-M was exceeded at two sites in the 

Neuse River Basin. Copper concentrations of 430 and 

1,900 ppm occurred in the upper Neuse River Basin 

near Falls Lake (fig. 6).

Copper 13
80° 79° 78° 77°

C North Carolina " >.. <P

50 100 MILES

0 50 100 KILOMETERS

EXPLANATION ' ;. 

 - BASIN BOUNDARY '^-.'S

o COPPER CONCENTRATION LESS THAN OR 

EQUAL TO 70 PARTS PER MILLION (table 1)

 COPPER CONCENTRATION GREATER THAN 

70 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 390 PARTS PER MILLION (table 1)

 COPPER CONCENTRATION GREATER THAN 

390 PARTS PER MILLION (table 1)

35°-

Base from U.S. Environmental Protection Agency, digital data, 1500.000 

Albers equal area projection

Figure 6. Maximum copper concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

14 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Iron

Iron is the fourth most abundant of all metals of 

the Earth's outer crust and is the base metal for steel 

(Weast, 1983). Iron is an important element for the 

proper development of plants and animals (Weast, 

1983).

Iron concentrations were detected in about 99 

percent of the samples collected and at all 75 sites 

sampled in the four major river basins. One iron 

concentration was reported as less than 1,200 ppm. 

Detected iron concentrations ranged from 8.4 to 

67,600 ppm (table 3). Guideline concentrations used 

to evaluate iron in bed sediments for this report were 

20,000 ppm and 40,000 ppm, the OMEE lowest effect

level and severe effect level, respectively (table 1). The 

lowest effect level was exceeded in nearly 17 percent 

of the samples and at about 31 percent of the sites. The 

severe effect level was exceeded at about 9 percent of 

the sites sampled. All severe effect level exceedances 

for iron occurred in the Roanoke River Basin, and only 

one of these sites is not located on or near a lake or 

reservoir (fig. 7).

Lead

Lead is widely dispersed in sedimentary rocks 

(Hem, 1985). The metal is on the U.S. EPA's list of 

126 Priority Pollutants (U.S. Environmental

80° 79° 78° 77° 76°

37°

36°

35°

0 50 100 MILES I I h '

0 50 100 KILOMETERS

EXPLANATION '-.

 - BASIN BOUNDARY ~~ - ' N -.^ -f ° 

O IRON CONCENTRATION LESS THAN OR *"'' "S 

EQUAL TO 20,000 PARTS PER MILLION (table 1)

 IRON CONCENTRATION GREATER THAN

20,000 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 40,000 PARTS PER MILLION (table 1)

 IRON CONCENTRATION GREATER THAN 

40,000 PARTS PER MILLION (table 1)

____I_____________I_____________L_

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 7. Maximum iron concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico study 

unit, 1969-90.

Iron 15
Protection Agency, 1994). Lead is used for batteries, 

cable covering, plumbing, and ammunition. It has 

been used in paint, insecticide, and antiknock 

compounds for gasoline, and continues to be used for 

sound and vibration adsorption, X-ray shields, and 

fine glassware. Some forms of lead are highly toxic, 

and the inclusion of these compounds in gasoline, 

paint, and insecticides has been reduced because of 

potential health risks (Weast, 1983).

Lead was detected in about 88 percent of 696 

samples collected and occurred at about 96 percent of 

249 sites sampled. The highest lead concentrations 

occurred in the Chowan and Roanoke River Basins 

(fig. 4). Guidelines used in this report to evaluate lead 

concentrations in bed sediment are 35 ppm and 

110 ppm, the respective ER-L and ER-M determined

by Long and Morgan (1991) (table 1), and the 

screening threshold was 10 ppm. The ER-L was 

exceeded in 17 percent of the samples and at about 27 

percent of the sites where concentrations were 

detected. Concentrations also exceeding the ER-M of 

110 ppm were detected in 31 samples collected from 

26 sites. Many of these sites are on or near lakes and 

reservoirs, or outlying urban and industrial areas. The 

highest detected lead concentration of 687 ppm 

occurred in the central Chowan River Basin (fig. 8).

Magnesium

Magnesium is the eighth most abundant element 

in the Earth's crust and is important for plant and

80° 79° 78° 77° 76°

37°

36°

35°

North Carolina » *. <£>

0 50 100 KILOMETERS

EXPLANATION '-N 

 - BASIN BOUNDARY "«- .' N

o LEAD CONCENTRATION LESS THAN OR

EQUAL TO 35 PARTS PER MILLION (table 1)

 LEAD CONCENTRATION GREATER THAN

35 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 110 PARTS PER MILLION (table 1)

 LEAD CONCENTRATION GREATER THAN 

110 PARTS PER MILLION (table 1)

I I

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Alters equal area projection

Figure 8. Maximum lead concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico study 

unit, 1969-90.

16 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
animal development (Weast, 1983). Magnesium is a 

major constituent of the dark-colored ferromagnesian 

minerals in igneous rocks, and occurs also in 

sedimentary rocks such as dolomite, limestone, and 

other carbonates (Hem, 1985).

Magnesium was detected in all 84 samples 

collected at 49 sites. Concentrations ranged from 0.19 

to 11,800 ppm. The two highest concentrations were 

collected from sites in the upper Roanoke River 

Basin one is upstream from Roanoke, Va., and the 

other is at Philpott Lake. There are no current 

guidelines with which to evaluate magnesium 

concentrations in bed sediment.

Manganese

Manganese is an abundant element in the 

Earth's crust, and small quantities are essential for

normal growth in humans and animals (Weast, 1983). 

Manganese is used in steel production, for paint 

pigments, and to color glass.

Manganese was detected in slightly less than 

100 percent of 192 samples collected at about 99 

percent of 95 sites sampled. Detected concentrations 

of manganese ranged from 0.34 to 24,000 ppm 

(table 3). The highest concentration of manganese 

occurred at Belews Lake in the upper Roanoke River 

Basin (fig. 9). Guideline concentrations used to 

evaluate manganese in bed sediments for this report 

were 460 ppm and 1,100 ppm, OMEE's lowest effect 

level and severe effect level, respectively (table 1). The 

lowest effect level was exceeded in slightly more than 

38 percent of the samples and at about 54 percent of 

the sites. The severe effect level was exceeded in 

slightly more than 9 percent of the samples and almost 

16 percent of the sites sampled. Severe effect level

80° 79° 78" 77° 76°

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0 50 100 MILES

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Neuse

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35'

EXPLANATION *"\

 - BASIN BOUNDARY '">_. N o 

o MANGANESE CONCENTRATION LESS THAN OR ' - ^/ "*" " X

EQUAL TO 460 PARTS PER MILLION (table 1) 

_ « MANGANESE CONCENTRATION GREATER THAN 460 PARTS PER °

MILLION AND LESS THAN OR EQUAL TO 1,100 PARTS '~"'' - ' >. ..* 

PER MILLION (table 1) '" "~. ' C .. 

 MANGANESE CONCENTRATION GREATER THAN 

1,100 PARTS PER MILLION (table 1)

________I_________________I__________

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 9. Maximum manganese concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

Manganese 17
exceedances for manganese occurred in the Roanoke 

River Basin, the upper Neuse River Basin, and the Tar 

River Basin. Only the site in the Tar River Basin is not 

located on or near a lake or reservoir (fig. 9).

Mercury

Mercury is a toxic trace element that occurs in 

volcanic rock and is listed on the U.S. EPA's list of 

126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994). It is widely dispersed in the 

environment as a result of the smelting of ores and the 

burning of fossil fuels (Hem, 1985). It is used in 

detonators for explosives, switches for electrical 

components, thermometers, barometers, pesticides, 

paints, signs, batteries, and amalgams. Mercury was 

used for many years as a fungicide in the pulp and 

paper industry (Novick and Cottrell, 1971). Organic 

mercury complexes are produced by methanegenerating bacteria in lake or stream sediment, and 

bioaccumulate in fish and shellfish (Hem, 1985).

Mercury was detected in nearly 52 percent of 

568 samples collected and was detected at almost 58 

percent of 257 sites sampled (table 3). The most 

guideline exceedances occurred in the Roanoke River 

Basin (fig. 4). Guidelines used in this report to 

evaluate mercury concentrations in bed sediment were 

0.15 ppm and 1.3 ppm, the respective ER-L and ER-M 

determined by Long and Morgan (1991), and 0.3 ppm, 

the index of potential contamination for mercury by 

VADEQ (table 1). The screening threshold was 

0.15 ppm.

The ER-L was exceeded in more than 13 

percent of the samples and at about 23 percent of the 

sites sampled. Mercury concentrations greater than 

0.15 ppm were detected at 59 sites, and concentrations 

greater than 0.30 ppm (the index of potential 

contamination by VADEQ) were detected at 20 sites 

(fig. 10). Several sites with concentrations greater than 

the ER-L are clustered among reservoirs or near urban 

or industrial areas.

Six samples exceeding the ER-M were collected 

at five sites; two of these sites are in the Neuse and 

Chowan River Basins and three are in the Roanoke 

River Basin. The highest concentration of 47 ppm was 

detected at one site on the Dan River downstream from 

Eden, N.C.; another site east of Danville, Va., had a 

mercury concentration of 15 ppm.

Nickel

Nickel is a trace element that occurs in crustal 

rocks (Hem, 1985). Some nickel compounds are toxic, 

and nickel is on the U.S. EPA's list of 126 Priority 

Pollutants (U.S. Environmental Protection Agency, 

1994). Nickel and nickel compounds are alloyed with 

other metals and used for coins, plating, in ceramics 

and batteries, and for hydrogenating vegetable oils 

(Weast, 1983).

Nickel was detected in nearly 93 percent of 564 

samples collected and occurred at about 87 percent of 

the 224 sites sampled (table 3). Guidelines used in this 

report to evaluate nickel concentrations in bed 

sediment were the ER-L (30 ppm) and the ER-M 

(50 ppm) used by Long and Morgan (1991), and the 

screening threshold was 4 ppm (table 1). The ER-L 

was exceeded in about 13 percent of the samples and 

at almost 13 percent of the sites where samples were 

collected. Several sites in the Roanoke River Basin 

that have ER-L exceedances are clustered among lakes 

and reservoirs along the upper reaches of the Roanoke 

and Dan Rivers. Exceedances of the ER-L in the 

Chowan River Basin (fig. 4) occurred near outlying 

industrial or urban areas, or near a wetland lake.

Most guideline exceedances and the highest 

median concentration occurred in the Roanoke River 

Basin (fig. 4). Nickel concentrations exceeded the 

ER-M of 50 ppm at eight sites (fig. 11). Seven sites are 

in reservoirs in the Roanoke River Basin. The 

maximum nickel concentration of 2,000 ppm occurred 

in the Tar River Basin. Further investigation is needed 

to determine the validity of the concentration reported 

at this site.

Selenium

Selenium is an important trace element that 

occurs in volcanic and sedimentary rocks; however, 

concentrations of some selenium compounds may be 

toxic to plants and animals (Weast, 1983). Selenium is 

on the U.S. EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994). Selenium 

and selenium compounds are used in toner for 

photocopying, and are important materials for the 

production of photo and solar cells (Weast, 1983).

Selenium was detected in about 65 percent of 

238 samples collected in the Neuse, Roanoke, and 

Chowan River Basins. Selenium was detected at more 

than 74 percent of the 90 sites sampled.

18 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
80° 79° 78° 77° 76°

37°

36°

35°

"v:

North Carolina - "- * . <P 'v

0 50 100 MILES

I i 

0 50 100 KILOMETERS

EXPLANATION

 - BASIN BOUNDARY 7 

o MERCURY CONCENTRATION LESS THAN OR^~ ''

EQUAL TO 0.15 PARTS PER MILLION (table 1) 

« MERCURY CONCENTRATION GREATER THAN 0.15 PARTS PER

MILLION AND LESS THAN OR EQUAL TO 0.30 PARTS 'v,.. 

PER MILLION (table 1)

 MERCURY CONCENTRATION GREATER THAN 0.30 PARTS PER MILLION 

AND LESS THAN OR EQUAL TO 1.3 PARTS PER MILLION (table 1)

 MERCURY CONCENTRATION GREATER THAN 1.3 PARTS PER MILLION 

(table 1)

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 10. Maximum mercury concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

Selenium 19
80° 79° 78° 77° 76°

37°

36"

35°

0 50 100 MILES

I , H ' 

0 50 100 KILOMETERS

EXPLANATION 

 BASIN BOUNDARY

o NICKEL CONCENTRATION LESS THAN OR 

EQUAL TO 30 PARTS PER MILLION (table 1)

 NICKEL CONCENTRATION GREATER THAN

30 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 50 PARTS PER MILLION (table 1)

 NICKEL CONCENTRATION GREATER THAN 

50 PARTS PER MILLION (table 1)

______I__________________I___________

Base from U.S. Environmental Protection Agency, digital data, 1 :500,000 

Albers equal area projection

Figure 1 1 . Maximum nickel concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

There are no current guidelines with which to 

evaluate selenium concentrations in bed sediment. The 

highest selenium concentration detected, 24 ppm, was 

from a site on Smith Mountain Lake, Va., in the upper 

Roanoke River Basin.

Thallium

Chowan River Basins. Thallium was detected at more 

than 27 percent of 33 sites sampled. There are no 

current guidelines with which to evaluate thallium 

concentrations in bed sediment. The highest thallium 

concentrations of 8.8 ppm and 6.7 ppm were detected 

in samples collected from the Chowan River Basin in 

Virginia.

Thallium is a trace element that occurs in 

igneous rocks. Although highly toxic, thallium has 

been used for some medicinal purposes (Weast, 1983). 

The metal is on the U.S. EPA's list of 126 Priority 

Pollutants (U.S. Environmental Protection Agency, 

1994). Thallium was used in rodenticides and 

insecticides in the United States until banned in 1975.

Thallium was detected in more than 22 percent 

of 63 samples. All detections were in the Roanoke and

Zinc

Zinc is a trace element that occurs in crustal 

rocks (Hem, 1985). Zinc is important for the proper 

development of animals (Weast, 1983) but in high 

concentrations can be toxic to plants. The metal is on 

the U.S. EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994). It is used for 

galvanizing steel and for making alloys of brass,

/

20 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
silver, and solders. Zinc and zinc compounds have a 

wide range of applications that include pigments for 

paint, batteries, plastics, soap, and pharmaceuticals.

Zinc was detected in almost 100 percent of 684 

samples collected and at slightly more than 99 percent 

of 249 sites sampled (table 3). Guidelines used in this 

report to evaluate zinc concentrations in bed sediment 

were the ER-L of 120 ppm and the ER-M of 270 ppm 

(table 1), and the screening threshold was 10 ppm. The 

ER-L was exceeded in more than 13 percent of the 

samples and at nearly 20 percent of the sites sampled. 

Several sites with ER-L exceedances are in the Coastal 

Plain; a few of these are near the mouth of the 

Roanoke or Neuse Rivers, or in outlying urban areas. 

Many sites where zinc concentrations exceeded the 

ER-L are from lakes and reservoirs and urban or 

industrial areas.

Zinc concentrations exceeded the ER-M at 13 

sites in the Chowan, Roanoke, and Neuse River 

Basins. The highest zinc concentration of 950 ppm 

occurred in the upper Neuse River Basin. The highest 

median concentration was in the Roanoke River Basin 

(figs. 4 and 12).

NUTRIENTS

Nutrients are compounds required for plant and 

animal development. The nutrients discussed in this 

report include nitrite plus nitrate, ammonia, ammonia 

plus organic nitrogen, total phosphorus, and 

orthophosphorus. Nitrogen and phosphorus are the 

primary nutrients in aquatic systems. In the 

Albemarle-Pamlico study unit, nitrogen and 

phosphorus contribute to water-quality problems

80° 79° 78° 77° 76°

37°

36°

35C

"V.

0 50 100 MILES

I i i 

0 50 100 KILOMETERS

EXPLANATION '-> 

 BASIN BOUNDARY ' 

o ZINC CONCENTRATION LESS THAN OR

EQUAL TO 120 PARTS PER MILLION (table 1)

 ZINC CONCENTRATION GREATER THAN

120 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 270 PARTS PER MILLION (table 1)

 ZINC CONCENTRATION GREATER THAN 

270 PARTS PER MILLION (table 1)

______I_________________I

\ Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 12. Maximum zinc concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico study 

unit, 1969-90.

Nutrients 21
associated with eutrophication. Lowest effect levels 

and severe effect levels were used as guidelines to 

evaluate total phosphorus and ammonia plus organic 

nitrogen (or total Kjeldahl nitrogen) in bed sediment 

(table 1). A summary of the data is presented in 

table 4. Data plotted on maps are the maximum 

detected concentrations at sites where analyses are 

available. Although nutrient samples were collected in 

each of the major river basins in North Carolina, fewer 

sites were sampled for nutrients than for metals and 

trace elements or pesticides. Data were not available in 

WATSTORE or STORET databases for nutrient 

concentrations in bed sediment in Virginia.

Nitrite plus Nitrate

Natural nitrite and nitrate deposits rarely occur 

in soils or sediments, except in desert alkaline soils 

(Fairbridge, 1972). Nitrite and nitrate are nitrogen 

species; nitrate is frequently associated with fertilizers 

and livestock in agricultural areas and domestic 

wastewater (Hem, 1985).

Nitrite plus nitrate was detected in 48 percent of 

197 samples and at about 72.4 percent of the 58 sites 

sampled (table 4). Four samples had concentrations 

greater than 400 ppm three from the lower Chowan 

River and one from Kerr Lake in the Roanoke River 

Basin. The highest concentration, 500 ppm, was 

detected on the lower Chowan River. There are no

current guidelines with which to evaluate nitrite plus 

nitrate concentrations in bed sediment.

Ammonia

Significant amounts of ammonia may be bound 

in clays (Fairbridge, 1972). Ammonia is applied to 

crops as a fertilizer and may occur in runoff from 

livestock areas.

Ammonia was detected in concentrations above 

the minimum reporting level in 90 percent of 139 

samples and at slightly more than 95 percent of 45 

sites sampled (table 4). Four sites had ammonia 

concentrations greater than 100 ppm two river sites 

at the mouth of the lower Chowan River Basin and two 

reservoir sites in the Roanoke River Basin. The 

highest ammonia concentration of 220 ppm was 

reported for a site at Kerr Lake (fig. 1). There are no 

current guidelines with which to evaluate ammonia 

concentrations in bed sediment.

Ammonia Plus Organic Nitrogen

Laboratory analysis for organic nitrogen 

typically includes ammonia; hence, results are 

reported as ammonia plus organic nitrogen (or total 

Kjeldahl nitrogen). Organic nitrogen accounts for 

most of the nitrogen in sediments (Fairbridge, 1972).

Table 4. Occurrence of selected nutrients in bed sediments of the Albemarle-Pamlico study unit, 1969-90

[ppm, parts per million; , not available]

Nutrient

Nitrite + nitrate

Ammonia

Total ammonia

plus organic

nitrogen

Orthophosphorus

Total phosphorus

Number

of

samples

197

139

98

136

199

Number

of 

sites

sampled

58

45

43

43

57

PcrcGnt"

age 

of

samples 

with

detected 

concentrations

48

90

100

45

100

Percentage

of sites

with

detected 

concentrations

72.4

95.6

100

65.1

100

Range of

detected

concentrations 

(ppm)

0.14-500

0.4-220

33-110

0.05-230

7.2-3,700

Evaluation

guideline 

(ppm)

5503

6003

Percentage of 

samples with

concentrations greater

than 

evaluation 

guideline

53

13.6

Percentage 

of sites with

concentrations

greater than 

evaluation 

guideline

72

32.7

aPersaud and others, 1993.

22 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Total ammonia plus organic nitrogen was 

detected in all 98 samples collected at 43 sites. 

Concentrations exceeded the lowest effect level of 

550 ppm in 53 percent of the samples and at 72 

percent of the sites (table 4). Concentrations exceeded 

the severe effect level of 4,800 ppm at eight sites. Four 

sites are on lakes or reservoirs; three of these sites are 

in the Roanoke River Basin, and one site is in the Tar 

River Basin. The remaining four sites are along the 

lower reaches of the Chowan River (fig. 13).

Total Phosphorus and Orthophosphorus

Phosphorus occurs in igneous rocks and is 

abundant in sediments. Phosphorus is used in 

fertilizers, pesticides, and water softeners, but has 

been banned from use in detergents by North Carolina

and Virginia because it has been identified as a major 

cause of eutrophication.

Total phosphorus was detected in all 199 

samples collected at 57 sites. Concentrations exceeded 

the lowest effect level of 600 ppm in nearly 14 percent 

of the samples collected and at more than 32 percent 

of the sites sampled (table 4). The lowest effect level 

for total phosphorus was exceeded at many of the 

same sites where the lowest effect level was exceeded 

for ammonia plus organic nitrogen. Two 

concentrations of 3,700 ppm and 2,800 ppm exceeded 

the severe effect level of 2,000 ppm; both were 

collected at the same site near the mouth of the Neuse 

River (fig. 14).

Orthophosphorus is the principal bioavailable 

form of phosphorus. Only small amounts of 

phosphorus are water soluble because aluminum,

80° 79° 78° 77° 76°

37°

36°

35°

.. i.- Virginia

... .. V--' VI

Roanoke

 s-.

North Carolina "'" " 

o so 100 MILES

I r S 

0 50 100 KILOMETERS

EXPLANATION

Tar

Neuse

\.

 - BASIN BOUNDARY X- . N

o AMMONIA PLUS ORGANIC NITROGEN ' '-. J'"V 

CONCENTRATION LESS THAN OR EQUAL TO 

550 PARTS PER MILLION (table 1)

 AMMONIA PLUS ORGANIC NITROGEN CONCENTRATION

GREATER THAN 550 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 4,800 PARTS PER MILLION (table 1)

 AMMONIA PLUS ORGANIC NITROGEN CONCENTRATION 

GREATER THAN 4,800 PARTS PER MILLION (table 1)

________I__________________I__________________\__

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 13. Maximum ammonia plus organic nitrogen concentrations detected in bed sediment from major river basins in the 

Albemarle-Pamlico study unit, 1969-90.

Nutrients 23
80° 79° 78° 77° 76°

37° -

36C

35°

.'J

Roanoke

. North Carolina " ^. °

0 50 100 MILES

 I r-h '

0 50 100 KILOMETERS

EXPLANATION ~%

 - BASIN BOUNDARY '~_.-N ° 

o TOTAL PHOSPHORUS CONCENTRATION ' *-.-"r "x. 

LESS THAN OR EQUAL TO 600 PARTS PER MILLION (table 1)

- TOTAL PHOSPHORUS CONCENTRATION GREATER THAN 

600 PARTS PER MILLION AND LESS THAN OR 

EQUAL TO 2,000 PARTS PER MILLION (table 1) 

 TOTAL PHOSPHORUS CONCENTRATION

GREATER THAN 2.000 PARTS PER MILLION (table 1)

O Neuse " v --

\.

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 14. Maximum total phosphorus concentrations detected in bed sediment from major river basins in the AlbemarlePamlico study unit, 1969-90.

calcium, iron, and other clay minerals bond with 

phosphate to render it insoluble.

Orthophosphorus was detected in 45 percent of 

136 samples and at 28 of the 43 sites sampled 

(table 4). Four orthophosphorus concentrations greater 

than 50 ppm were collected from two sites in the lower 

Neuse River Basin. The highest orthophosphorus 

concentration, 230 ppm, was detected near the mouth 

of the Neuse River. There are no current guidelines 

with which to evaluate orthophosphorus 

concentrations in bed sediment.

PESTICIDES AND PCB'S

Since the late 1800's, many synthetic organic 

compounds have been produced and introduced into

the environment. Polychlorinated biphenyls (PCB's) 

have been used as dielectrics for electrical 

transformers, plasticizers, and flame retardants. PCB's 

and many pesticides are persistent in the environment, 

accumulate in the fatty tissues of animals, and can 

biomagnify through the food chain. The use of some 

of these compounds has been banned in the United 

States (Ware, 1989).

For the purposes of this report, DDD, DDE, and 

DDT are treated as separate compounds and 

equivalent to the p,p'- or sum of respective p,p'- and 

o,p'- components. Statistics regarding the occurrence 

of pesticides and PCB's are presented in table 5. 

Guidelines used to evaluate pesticides and PCB's are 

the ER-L and the ER-M concentrations from Long and 

Morgan (1991), or lowest effect levels from OMEE 

(table 2). Data presented in maps are maximum

24 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Table 5. Occurrence of selected pesticides and PCB's in bed sediments of the Albemarle-Pamlico study unit, 1969-90

[ppb, parts per billion; , not available]

Pesticide/ 

PCB's

Aldrin

Atrazine

Chlordane

ODD

DDE

DOT

Dieldrin

Endrin

Heptachlor

Toxaphene

PCB's

Number 

of 

samples

205

104

169

156

160

162

17i

196

164

168

72

Number 

of 

sites 

sampled

84

53

73

72

72

72

76

89

68

72

53

Percentage 

of samples 

with 

detected 

concentrations

10.2

20.2

11.2

26.3

28.1

18.5

18.7

1.5

.6

1.2

1.4

Percentage 

of sites 

with 

detected 

concentrations

25

38.2

17.8

25

26.4

19.4

15.8

2.2

1.5

1.4

1.9

Evalua- Percen«ageof 

Range of . samples with

detected . . concentrations Quideconcentra- .. greater than

tions(ppb) . evaluation 

lpp ' guideline

0.02-0.1 2a 0

0.03-0.1 

0.6-80 .5b 11.2

0.1-58 2b 12.8

0.1-37 2b 10.6

0.1-30 lb 11.7

0.02-11 .02b 17.5

0.2-1 .02b 1.5

8.1 C 

16.03-33.74 

680C 50b 1.4

Percentage 

of sites with 

concentrations 

greater than 

evaluation 

guideline

0

17.8

12.5

8.3

13.9

15.8

2.2

i.9

"Persaud and others, 1993. 

bLong and Morgan, 1991. 

cOne observation above the minimum reporting level.

detected values for each site, reported in parts per 

billion (ppb).

Many pesticide concentrations that exceeded 

guidelines occurred at sites in the lower Tar River 

Basin. These sites drain agricultural areas near an 

intensively sampled section of the lower Tar River 

Basin near Greenville, N.C. (Mason and others, 1990). 

Other areas in the upper Neuse River Basin near Falls 

Lake and Durham, N.C., also were sampled 

intensively (Garrett and others, 1994). Some 

exceedances occurred in the Chowan, Neuse, and 

Roanoke River Basins; however, few exceedances 

occurred relative to the number of sites sampled.

Aldrin

Aldrin is one of several agricultural insecticides 

known as chlorinated cyclodienes. The use of aldrin 

was banned in 1984, and it is no longer sold in the 

United States (Ware, 1989; Meister Publishing 

Company, 1994). Aldrin is on the U.S. EPA's list of

126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994).

Aldrin was detected in about 10 percent of 205 

samples collected for aldrin analysis. Aldrin 

concentrations were detected at 25 percent of 84 sites 

sampled, and detected concentrations ranged from 

0.02 to 0.1 ppb (table 5). The guideline used to 

evaluate aldrin concentrations was the lowest effect 

level determined by OMEE (table 2). There were no 

exceedances of the guideline for aldrin in bed 

sediment.

Atrazine

Atrazine is a herbicide used heavily in corn 

production and was the most extensively used 

pesticide in the United States during 1987 (Ware, 

1989). Atrazine was detected in about 20 percent of 

104 samples collected and at about 38 percent of 53 

sites sampled. Detected atrazine concentrations ranged 

from 0.03 to 0.1 ppb. There are no current guidelines

Pesticides and PCB's 25
with which to evaluate atrazine concentrations in bed 

sediment (table 5).

Chlordane

Chlordane is a chlorinated cyclodiene 

insecticide developed in 1945. Chlordane use as a 

general insecticide was banned by 1980, and its use as 

a termiticide is currently restricted (Ware, 1989; 

Meister Publishing Company, 1994). Chlordane is on 

the U.S. EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994).

Chlordane was detected in about 11 percent of 

169 samples collected and at 18 percent of 73 sites 

sampled. The guidelines used to evaluate chlordane 

concentrations were the ER-L and ER-M, 0.5 ppb and 

6 ppb, respectively (table 2). All detected

concentrations exceeded the ER-L for chlordane and 

ranged from 0.6 to 80 ppb (table 5). Sites with ER-L 

exceedances were clustered in the upper Neuse River 

Basin. In addition, concentrations exceeded the ER-M 

at four sites in the Chowan, Tar, and Neuse River 

Basins (fig. 15).

ODD

ODD is an insecticide that was used on fruits 

and vegetables before it was banned by the U.S. EPA 

in the early 1970's (Ware, 1989). ODD is on the U.S. 

EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994).

Concentrations of ODD were detected in about 

26 percent of 156 samples collected for analysis and 

ranged from 0.1 to 58 ppb (table 5). Concentrations

80° 79° 78° 77° 76°

37°

36°

35C

North Carolina '"* -* . 0

EXPLANATION "^ 

 --- BASIN BOUNDARY "~-

o CHLORDANE CONCENTRATION LESS THAN OR

EQUAL TO 0.5 PART PER BILLION (table 2) /

 CHLORDANE CONCENTRATION GREATER THAN 

0.5 PART PER BILLION AND LESS THAN OR 

EQUAL TO 6 PARTS PER BILLION (table 2)

 CHLORDANE CONCENTRATION GREATER THAN 

6 PARTS PER BILLION (table 2)

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Alters equal area projection

Figure 15. Maximum chlordane concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

26 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
were detected at 25 percent of 72 sites sampled. DDD 

exceeded the ER-L of 2 ppb in nearly 13 percent of the 

samples collected and at more than 12 percent of the 

sites sampled in the Chowan, Roanoke, and Tar River 

Basins (fig. 16). Concentrations that exceeded the 

ER-M of 20 ppb were detected in four samples 

collected at three sites in the Tar River Basin.

DDE

DDE is a degradation product of DDT, and is on 

the U.S. EPA's list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994). 

Concentrations of DDE were detected in slightly more 

than 28 percent of 160 samples collected for analysis. 

Concentrations of DDE were detected at about 26 

percent of the 72 sites that were sampled and ranged

from 0.1 to 37 ppb (table 5). Concentrations of DDE 

that exceeded the ER-L of 2 ppb were detected in 

nearly 11 percent of the samples collected and at more 

than 8 percent of the sites sampled. All exceedances 

were in the Roanoke and Tar River Basins (fig. 17). 

Concentrations that exceeded the ER-M of 15 ppb 

were detected in four samples collected at three sites 

in the Tar River Basin.

DDT

DDT was probably the most commonly used 

pesticide between 1939 and 1960. Because DDT is 

persistent and biomagnifies through the food chain, all 

uses of DDT were banned by the U.S. EPA in 1973 

(Ware, 1989). DDT is on the U.S. EPA's list of 126

80° 79° 78° 77° 76°

> & ^

o

CO

37° o <R9<£S9 0o

Roanoke

-f----Q-0-.-o36° North Carolina "'""

0 50 100 MILES I I '

0 50 100 KILOMETERS

"s- o °0 v

i 

s

(f

35C

/

EXPLANATION "-7.

 - BASIN BOUNDARY ~~"' N -.^ J- °

O DDD CONCENTRATION LESS THAN OR ^ - 

EQUAL TO 2 PARTS PER BILLION (table 2)

 DDD CONCENTRATION GREATER THAN

2 PARTS PER BILLION AND LESS THAN OR 

EQUAL TO 20 PARTS PER BILLION (table 2)

 DDD CONCENTRATION GREATER THAN 

20 PARTS PER BILLION (table 2)

____L___________I____________

\..

Neuse

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 16. Maximum DDD concentrations detected in bed sediment from major river basins in the Albemarle-Pamhco study 

unit, 1969-90.

DDT 27
80° 79° 78° 77° 76°

37°

-f - ---°-0--_o. 0 _ _°__-_

"'I ,-"^--V. :' -

T- o X

36°

35C

, '"* '

> <P %,.

I.-

00 o ° ° 

o Cfe'ioSQ ° o

Virginia

 \..-''"'v

I

^- --"'V -^ 

 - '^ ~^ . \^.

\

Uoawofcc

o V.

v:

North Carolina """""x-. o °0 \

0 50 100 MILES I i S '

0 50 100 KILOMETERS

EXPLANATION 

 -- BASIN BOUNDARY

o DDE CONCENTRATION LESS THAN OR

--..-'"x.

EQUAL TO 2 PARTS PER BILLION (table 2) f

DDE CONCENTRATION GREATER THAN 

2 PARTS PER BILLION AND LESS THAN OR 

EQUAL TO 15 PARTS PER BILLION (table 2)

\..

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 17. Maximum DDE concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

28 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
Priority Pollutants (U.S. Environmental Protection 

Agency, 1994).

Concentrations of DDT were detected in more 

than 18 percent of 162 samples collected for analysis 

at 72 sites (table 5). Concentrations of DDT were 

detected at slightly more than 19 percent of the sites 

and ranged from 0.1 to 30 ppb. Concentrations of 

DDT that exceeded the ER-L of 1 ppb were detected 

in nearly 12 percent of the samples and at about 14 

percent of the sites sampled (fig. 18). Concentrations 

that exceeded the ER-M of 7 ppb were detected in 

seven samples collected at three sites in the Tar River 

and at two sites in the Roanoke River Basin.

Dieldrin

Dieldrin is a chlorinated insecticide used on 

crops. The U.S. EPA banned the use of dieldrin in 

1986 (Ware, 1989), and it is on the U.S. EPA's list of 

126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994). Dieldrin was detected in 

about 19 percent of 171 samples collected for analysis. 

Concentrations of dieldrin were detected at nearly 16 

percent of 76 sites that were sampled, and detected 

concentrations ranged from 0.02 to 11 ppb (table 5). 

Concentrations of dieldrin that exceeded the ER-L of 

0.02 ppb were detected in nearly 18 percent of the 

samples and at nearly 16 percent of the sites sampled

80° 79° 78° 77° 76°

37°

36°

35°

EXPLANATION '-^ 

 - - - BASIN BOUNDARY '^- . N

o DDT CONCENTRATION LESS THAN OR 

EQUAL TO 1 PART PER BILLION (table 2)

 DDT CONCENTRATION GREATER THAN

1 PART PER BILLION AND LESS THAN OR 

EQUAL TO 7 PARTS PER BILLION (table 2)

 DDT CONCENTRATION GREATER THAN 

7 PARTS PER BILLION (table 2)

Base from U.S. Environmental Protection Agency, digital date, 1:500,000 

Albers equal area projection

Figure 18. Maximum DDT concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

Dieldrin 29
(fig. 19). A concentration that exceeded the ER-M of 

8 ppb was detected in the Tar River Basin.

Endrin

Endrin is a chlorinated cyclodiene pesticide that 

was used in orchards to control birds and mice and on 

cotton to control insects. Endrin is on the U.S. EPA's 

list of 126 Priority Pollutants (U.S. Environmental 

Protection Agency, 1994), and its use has been 

discontinued in the United States (Ware, 1989).

Endrin was detected in nearly 2 percent of 196 

samples collected for analysis (table 5). Endrin was 

detected at more than 2 percent of 89 sites that were 

sampled, and detected concentrations ranged from 0.2 

to 1 ppb. Concentrations of endrin that exceeded the 

ER-L of 0.02 ppb were detected in three of the

samples and at two sites in the Tar River Basin. No 

concentrations exceeded the ER-M of 45 ppb for 

endrin concentrations in bed sediment.

Heptachlor

Heptachlor is a chlorinated cyclodiene 

insecticide that was used primarily as a termiticide. 

The U.S. EPA banned the use of heptachlor in 1988 

(Ware, 1989) and included heptachlor on its list of 126 

Priority Pollutants (U.S. Environmental Protection 

Agency, 1994).

Heptachlor was detected in 0.6 percent of 164 

samples collected at 68 sites (table 5). One heptachlor 

concentration of 8.1 ppb was from a site in an 

agricultural area of the lower Tar River Basin. There

80°

J-M 

79° 78° 77° 76°

 I 

Virginia

©

^ i,""^

.'J

37°

0 o ' \_ ". ** ""* ' 

CO ° o o V-- ,- -^ .-"''

^ v.-7 o<P6><£9 0o° o ,

° :. ° N

Roanoke o v..

^ - - _ -Q

' / ,- '" (. '^ _.<'

 ^ 1 -,- ^ .

 ' ^ 1- . .rx

 x..x

36° t »

North Carolina " N.. 0 «0

0 50 100 MILES

I r

*-.-*\

35°

0 50 100 KILOMETERS - ^ X.

I ° Neuse "\,

\.

EXPLANATION '-> 

 - BASIN BOUNDARY

o DIELDRIN CONCENTRATION LESS THAN OR 

EQUAL TO 0.02 PART PER BILLION (table 2)

 DIELDRIN CONCENTRATION GREATER THAN 

0.02 PART PER BILLION AND LESS THAN OR 

EQUAL TO 8 PARTS PER BILLION (table 2)

 DIELDRIN CONCENTRATION GREATER THAN 

8 PARTS PER BILLION (table 2)

______I_________________|___________

\..

I

Base from U.S. Environmental Protection Agency, digital data, 1:500,000 

Albers equal area projection

Figure 19. Maximum dieldrin concentrations detected in bed sediment from major river basins in the Albemarle-Pamlico 

study unit, 1969-90.

30 Water-Quality Assessment of the Albemerle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
are no current guidelines with which to evaluate 

heptachlor concentrations in bed sediment.

Toxaphene

Toxaphene is a chlorinated insecticide 

developed in 1947. The U.S. EPA banned most uses of 

toxaphene in 1983 (Ware, 1989) and included 

toxaphene on its list of 126 Priority Pollutants (U.S. 

Environmental Protection Agency, 1994).

Toxaphene was detected in 1.2 percent of 168 

samples collected at 72 sites (table 5). Two detected 

toxaphene concentrations of 16.0 and 33.7 ppb were 

from samples collected at one site in the lower reaches 

of the Roanoke River Basin. There are no current 

guidelines with which to evaluate toxaphene 

concentrations in bed sediment.

PCB's

Polychlorinated biphenyls (PCB's) are 

industrial and commercial compounds used for a 

variety of purposes. PCB's have qualities similar to 

pesticides such as DDT they are persistent, 

biomagnify, and have been banned from production in 

the United States since 1977 (Tigler and others, 1990). 

PCB's also are on the U.S. EPA's list of 126 Priority 

Pollutants (U.S. Environmental Protection Agency, 

1994).

PCB's were detected in 1.4 percent of 72 

samples collected for analysis at 53 sites (table 5). 

PCB's were detected at a site in the Chowan River 

Basin on the Blackwater River near Franklin, Va. The 

concentration of 680 ppb exceeded the ER-L and 

ER-M of 50 ppb and 400 ppb, respectively (table 2).

SUMMARY AND CONCLUSIONS

Long-range goals of the NAWQA Program are 

to describe the status and trends in surface- and 

ground-water resources. As part of meeting these 

goals, historical bed-sediment data from WATSTORE 

and STORET databases were screened and evaluated 

using sediment-quality guidelines from various 

agencies. Site selection was not determined randomly; 

therefore, results may not indicate average conditions. 

Further investigation is required to characterize bedsediment chemistry and particle-size distribution in 

the Albemarle-Pamlico study unit.

Bed-sediment data from WATSTORE and 

STORET were compiled to form a single database 

consisting of 1.049 records for 301 sites in the 

Albemarle-Pamlico study unit. These data were 

compared with sediment-quality guidelines developed 

by the National Oceanic and Atmospheric 

Administration, the Ontario Ministry of Environment 

and Energy, and the Virginia Department of 

Environmental Quality. Concentrations for 16 metals 

and trace elements, 5 nutrients, 10 pesticides, and 

PCB's were examined.

Sources of elevated concentrations may be from 

geologic formations or from activities that occur in 

urban and agricultural areas. Elevated concentrations 

also occur in depositional zones such as lakes and 

reservoirs, and near the mouths of rivers areas where 

stream velocities diminish and fine grain-size particles 

settle on the streambed. The Roanoke River Basin has 

more lakes and reservoirs than other basins in the 

study unit, which can explain elevated concentrations 

of some constituents in the Roanoke River Basin.

The highest concentrations of arsenic, 

beryllium, iron, magnesium, manganese, mercury, and 

selenium occurred in the Roanoke River Basin. 

Chromium and nickel concentrations were highest in 

the Tar River Basin. The highest concentrations of 

cadmium, lead, and thallium were detected in the 

Chowan River Basin, whereas copper and zinc were 

highest in the Neuse River Basin. Chromium, copper, 

lead, nickel, and zinc were the most frequently 

sampled and detected metals and trace elements, and 

the percentage of guideline exceedances was greater 

than 13 percent for iron, lead, manganese, mercury, 

nickel, and zinc concentrations.

Total phosphorus and ammonia plus organic 

nitrogen results suggest possible influences from 

urban areas, wastewater-treatment facilities, and 

agricultural areas. Elevated nitrogen and phosphorus 

concentrations occurred in lakes and reservoirs, and 

the lower reaches of the Roanoke, Chowan, and Neuse 

Rivers. High nutrient concentrations near the mouths 

of these rivers suggest a source of nitrogen and 

phosphorus in the sediment that might become 

available to aquatic plants and algae in sounds and 

estuaries when bed sediments are resuspended. Data 

were not available for nutrient concentrations in the 

upper reaches of the Roanoke and Chowan Rivers in 

Virginia.

Summary and Conclusions 31
Nutrient concentrations exceeded the guidelines 

at several sites in the lower Chowan River Basin and 

near Lake Gaston in the Roanoke River Basin. These 

sites drain mostly agricultural land; few sites were 

sampled in developed areas. Some nutrient 

concentrations exceeded the evaluation guidelines in 

each basin. Although fewer sites were sampled for 

nutrients than for metals and trace elements and 

pesticides, more data are needed to describe the 

distribution of nitrogen and phosphorus in sediments 

of the Albemarle-Pamlico study unit.

Sites where samples were collected and 

analyzed for pesticide concentrations were unevenly 

distributed in the study unit. However, pesticide 

concentrations were frequently detected in areas of 

intensive data collection such as the upper Neuse 

River Basin near Falls Lake and in the lower Tar River 

Basin. Elevated chlordane concentrations were 

reported for sites in each major river basin and were 

clustered in the upper Neuse River Basin. All sites 

sampled in the Tar River Basin for DDD, DDE, and 

DDT had concentrations greater than the effects 

range-low established by the National Oceanic and 

Atmospheric Administration. Elevated concentrations 

of DDD, DDE, and DDT also were detected at several 

sites in the Roanoke River Basin.

Additional sample collection and data analysis 

may reveal trends or sources of elevated 

concentrations of bed-sediment contaminants and the 

effect of grain size on nutrient and pesticide 

concentrations. A statistically based (random) 

sampling design and well-documented methods for 

additional studies also could improve the ability of 

water and wildlife-resource managers and scientists to 

better understand bed-sediment characteristics in the 

Albemarle-Pamlico study unit. Additional statistical 

tests or correlation analyses also may be helpful in 

understanding bed-sediment quality within the study 

unit.

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measurement of fluvial sediment: U.S. Geological 

Survey Open-File Report 86-531, 118 p.

Fairbridge, R.W., ed., 1972, The encyclopedia of 

geochemistry and environmental sciences, 

Encyclopedia of earth sciences series, volume IVA: 

New York, Van Nostrand Reinhold, 1,321 p.

Fenneman, N.M., 1938, Physiography of Eastern United 

States: New York, McGraw-Hill, 714 p.

Fishman, M.J., Raese, J.W., Gerlitz, C.N., and Husband, 

R.A., 1994, U.S. Geological Survey approved 

inorganic and organic methods for the analysis of 

water and fluvial sediment, 1954-94: U.S. Geological 

Survey Open-File Report 94-351, 55 p.

Garrett, R.G., Taylor, J.E., and Middleton, T.L., 1994,

Water-quality data for selected North Carolina streams 

and reservoirs in the Triangle Area Water Supply 

Monitoring Project, 1988-92: U.S. Geological Survey 

Open-File Report 94-379, 255 p.

Hem, J.D., 1985, Study and interpretation of the chemical 

characteristics of natural water (3d ed.): U.S. 

Geological Survey Water-Supply Paper 2254, 

263 p.

Horowitz, A.J., 1991, A primer on sediment-trace element 

chemistry (2d rev. ed.): Boca Raton, Fla., Lewis 

Publishers, 136 p.

Horowitz, A.J., and Elrick, K.A., 1987, The relation of 

stream sediment surface area, grain size and 

composition to trace element chemistry. Applied 

Geochemistry, v. 2, no. 4, p. 437-451.

 1988, Interpretation of bed sediment trace metal 

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Horowitz, A.J., Elrick, K.A., and Hooper, R.R, 1989, The 

prediction of aquatic sediment-associated trace 

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Leahy, P.P., Rosenshein, J.S., and Knopman, D.S., 1990, 

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Long, E.R., and Morgan, L.G., 1991, The potential for 

biological effects of sediment-sorbed contaminants 

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'94: Willoughby, Ohio, Meister Publishing Co., 

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32 Water-Quality Assessment of the Albemarle-Pamlico Drainage Basin A Summary of Selected Trace Element, Nutrient, and 

Pesticide Data for Bed Sediments, 1969-90
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national standards and guidelines for pesticides 

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their application to water-quality assessments: 

U.S. Geological Survey Open-File Report 94-44, 

115 p.

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Our world in peril An environment review: 

Greenwich, Conn., Fawcett Publications, Inc., 

498 p.

Persaud, D., Jaagumagi, R., and Hayton, A., 1993, 

Guidelines for the protection and management of 

aquatic sediment quality in Ontario: Ontario, 

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Energy, Water Resources Branch, 24 p.

Shelton, L.R., and Capel, P.O., 1994, Guidelines for 

collecting and processing samples of stream bed 

sediment for analysis of trace elements and organic 

contaminants for the National Water-Quality 

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Open-File Report 94-458, 20 p.

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L.D., and Gregory, R.A., 1990, Comprehensive 

review of selected toxic substances Environmental 

samples in Virginia: Virginia State Water Control 

Board Information Bulletin Number 583, 232 p.

U.S. Environmental Protection Agency, 1992, Sediment 

classification methods compendium: U.S. 

Environmental Protection Agency, 

EPA-823-R-92-006, 223 p.

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U.S. Environmental Protection Agency, 

EPA-823-B-94-005b, Appendix P, 3 p.

Ward, J.R., and Harr, C.A., eds., 1990, Methods for the 

collection and processing of surface-water and bedsediment samples for physical and chemical 

analysis: U.S. Geological Survey Open-File Report 

90-140, 70 p.

Weast, R.C., ed., 1983, CRC handbook of chemistry and 

physics (63d ed.): Boca Raton, Fla.. CRC Press. 

Inc., 2,381 p.

Ware, G.W., 1989, The pesticide book (3d ed): Fresno, 

Calif., Thomson Publications, 340 p.

Selected References 33