Cover photo: Streambed in upper Tennessee River Basin study area.
Seasonal and Spatial Variability of Pesticides in 

Streams of the Upper Tennessee River Basin, 

1996-99

By M.W. Treece, Jr.

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 03-4006

Nashville, Tennessee

2003
U.S. DEPARTMENT OF THE INTERIOR

Gale A. Norton, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Any use of trade, product, or firm name in this report is for identification

purposes only and does not constitute endorsement by the

U.S. Geological Survey.

For additional information write to: Copies of this report may be purchased from:

District Chief U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

640 Grassmere Park, Suite 100 Box 25286

Nashville, Tennessee 37211 Denver, Colorado 80225-0286

Information regarding the National Water-Quality Assessment (NAWQA) Program is available on the 

Internet via the World Wide Web. You may connect to the NAWQA home page at: 

http://water.usgs.gov/nawqa/naqwa_home.html
FOREWORD

Foreword iii

The U.S. Geological Survey (USGS) is committed to serve the Nation with accurate and timely scientific information that helps enhance and protect the 

overall quality of life, and facilitates effective management of water, biological, energy, and mineral 

resources. Information on the quality of the Nation’s 

water resources is of critical interest to the USGS 

because it is so integrally linked to the long-term 

availability of water that is clean and safe for drinking 

and recreation and that is suitable for industry, irrigation, and habitat for fish and wildlife. Escalating population growth and increasing demands for the multiple 

water uses make water availability, now measured in 

terms of quantity and quality, even more critical to the 

long-term sustainability of our communities and ecosystems.

The USGS implemented the National WaterQuality Assessment (NAWQA) Program to support 

national, regional, and local information needs and 

decisions related to water-quality management and 

policy. Shaped by and coordinated with ongoing 

efforts of other Federal, State, and local agencies, the 

NAWQA Program is designed to answer: What is the 

condition of our Nation’s streams and ground water? 

How are the conditions changing over time? How do 

natural features and human activities affect the quality 

of streams and ground water, and where are those 

effects most pronounced? By combining information 

on water chemistry, physical characteristics, stream 

habitat, and aquatic life, the NAWQA Program aims to 

provide science-based insights for current and emerging water issues. NAWQA results can contribute to 

informed decisions that result in practical and effective water-resource management and strategies that 

protect and restore water quality.

Since 1991, the NAWQA Program has implemented interdisciplinary assessments in more than 50 

of the Nation’s most important river basins and aquifers, referred to as Study Units. Collectively, these 

Study Units account for more than 60 percent of the 

overall water use and population served by public 

water supply, and are representative of the Nation’s 

major hydrologic landscapes, priority ecological 

resources, and agricultural, urban, and natural sources 

of contamination. 

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

analysis. The assessments thereby build local knowledge about water-quality issues and trends in a particular stream or aquifer while providing an 

understanding of how and why water quality varies 

regionally and nationally. The consistent, multi-scale 

approach helps to determine if certain types of waterquality issues are isolated or pervasive, and allows 

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

in the Nation’s diverse geographic and environmental 

settings. Comprehensive assessments on pesticides, 

nutrients, volatile organic compounds, trace metals, 

and aquatic ecology are developed at the national 

scale through comparative analysis of the Study-Unit 

findings. 

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

knowledge about water resources can be applied in 

management and policy decisions. We hope this 

NAWQA publication will provide you the needed 

insights and information to meet your needs, and 

thereby foster increased awareness and involvement in 

the protection and restoration of our Nation’s waters. 

The NAWQA Program recognizes that a 

national assessment by a single program cannot 

address all water-resource issues of interest. External 

coordination at all levels is critical for a fully integrated understanding of watersheds and for costeffective management, regulation, and conservation of 

our Nation’s water resources. The Program, therefore, 

depends extensively on the advice, cooperation, and 

information from other Federal, State, interstate, 

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

groups. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch

Associate Director for Water

Contents v

CONTENTS

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

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

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

Study Area ................................................................................................................................................................... 2 

Study Design................................................................................................................................................................ 4 

Selection of Sampling Sites and Sampling Frequency...................................................................................... 5 

Field and Laboratory Methods .......................................................................................................................... 5 

Quality Control ................................................................................................................................................. 8 

Estimated Pesticide Use in the Study Area ................................................................................................................. 8 

Pesticides in Streams of the Upper Tennessee River Basin................................................................................................... 10

Pesticides Detected in Streams.................................................................................................................................... 10

Comparisons of Detection Frequencies in the Upper Tennessee River Basin with

Detection Frequencies Across the Nation ..................................................................................................... 15

Water-Quality Standards.............................................................................................................................................. 16

Seasonal and Spatial Variability of Pesticides in Streams of the Upper Tennessee River Basin .......................................... 16

Summary................................................................................................................................................................................ 22

References ............................................................................................................................................................................. 23

Appendix A. Sites sampled for spatial analysis of pesticides in the upper Tennessee River Basin, 1996-98....................... 27

FIGURES

1. Map showing physiographic provinces, major subbasins, and land use of the upper Tennessee River Basin .......... 3

2. Map showing location of sampling sites in the upper Tennessee River Basin........................................................... 4

3-5. Graphs showing:

3. Detection frequency for all pesticides detected in at least 2 percent of samples at fixed sites

in the upper Tennessee River Basin, 1996-99.................................................................................................... 11

4. Pesticide detection frequency for the agricultural sites compared with the other fixed sites

in the upper Tennessee River Basin ................................................................................................................... 14

5. Pesticide detection frequencies in the upper Tennessee River Basin compared with 

national averages from previous National Water-Quality Assessment Program

investigations across the Nation......................................................................................................................... 15

6. Map showing location of stream sites with samples in which pesticide concentrations were equal to or 

exceeded aquatic-life criteria in the upper Tennessee River Basin ............................................................................ 17

7. Graphs showing seasonal variation in pesticide concentrations at agricultural sites in the 

upper Tennessee River Basin, 1996 ........................................................................................................................... 18

8-10. Maps showing:

8. Pesticides detected in samples collected at low flow from 28 stream sites in the 

Clinch, Powell, and Holston River Basins, 1996 and 1998 ............................................................................... 19

9. Pesticides detected in samples collected at low flow from 9 stream sites in the Emory 

River Basin and other tributaries to the upper Tennessee River, 1996............................................................... 20

10. Pesticides detected in samples from 30 stream sites in the French Broad 

and Nolichucky River Basins, 1997................................................................................................................... 21
vi Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

TABLES

1. Fixed sampling sites in the upper Tennessee River Basin study area........................................................................ 6

2. Pesticides and pesticide metabolites analyzed in samples collected from streams in 

the upper Tennessee River Basin, March 1996 through June 1999........................................................................... 7

3. Pesticides most commonly used for agriculture in the monitored part of the 

upper Tennessee River Basin, 1992........................................................................................................................... 9

4. Detection frequencies and maximum concentrations for pesticides detected in 

the upper Tennessee River Basin, 1996-99................................................................................................................ 12

CONVERSION FACTORS, DATUMS, WATER-QUALITY UNITS, AND ABBREVIATIONS

Temperature in degrees Celsius (oC) can be converted to degrees Fahrenheit (oF), and conversely, by use of the following 

equations: oF= (1.8 x oC) + 32 oC=( o

F-32)x 0.5555

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD of 1929).

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

Water-quality units

μg/L micrograms per liter

μm micrometer

mg/L milligrams per liter

Abbreviations and Acronyms

DCPA Dacthal

EWI Equal width increment

GC/MS Gas chromatography/mass spectrometry

HAL Health advisory limit

HCH Hexachlorocyclohexane

HPLC High-performance liquid chromatography

MCL Maximum contaminant level

MRL Minimum reporting level

NAFAP National Center for Food and Agricultural Policy

NAWQA National Water-Quality Assessment Program

SPE Solid-phase extraction

TVA Tennessee Valley Authority

U.S. EPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

UTEN Upper Tennessee River Basin

Multiply By To obtain

inch (in.) 2.54 centimeter

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

square mile (mi2) 2.590 square kilometer

acre-foot (acre-ft) 1.233x10-3 cubic meter

cubic foot per second (ft3/s) 2.447x10-3 cubic meter

billion gallons per day (Bgal/d) 4,381x10-2 cubic meters per second

inch per year (in/yr) 25.4 millimeter per year
Introduction 1

Seasonal and Spatial Variability of Pesticides in Streams 

of the Upper Tennessee River Basin, 1996-99

By M.W. Treece, Jr.

ABSTRACT

From 1996 to 1999, the U.S. Geological 

Survey conducted an assessment of pesticides in 

streams in the upper Tennessee River Basin 

(UTEN), which includes parts of Tennessee, North 

Carolina, Virginia, and Georgia. A total of 362 

water samples were collected at 13 fixed surfacewater sites from March 1996 through June 1999, 

and an additional 61 samples were collected 

throughout the UTEN during the spring and summers of 1996, 1997, and 1998. In 1996, 3 of the 

13 fixed sites located in agricultural watersheds 

were sampled intensively (weekly) for about 

8 months during the growing season. Water samples were analyzed for 85 herbicides, insecticides, 

and pesticide metabolites. Based on a threshold 

concentration of 0.01 microgram per liter, the 

most frequently detected herbicides were atrazine 

(59 percent); tebuthiuron (41 percent); the metabolite, deethylatrazine (31 percent); metolachlor 

(24 percent); simazine (17 percent); and prometon 

(6.4 percent). The insecticides detected most frequently were carbaryl (6.1 percent), diazinon 

(1.9 percent), carbofuran (1.7 percent), and 

chlorpyrifos (1.1 percent). Pesticide concentrations varied seasonally and were closely related to 

land use. The highest pesticide concentrations 

occurred in the agricultural watersheds in late 

spring and early summer (April through July), 

coinciding with pesticide application and the first 

substantial storm following pesticide application.

Results of the spatial analysis of pesticides 

during base-flow conditions indicate that waterquality conditions at the fixed sites were representative of conditions in the upper Tennessee River 

Basin. Although most of the water samples collected in the upper Tennessee River Basin contained detectable concentrations of one or more 

pesticides, none of the concentrations exceeded 

any human health guidelines.

INTRODUCTION

Pesticide use in the United States has greatly 

increased over the last several decades. Since the 

1940s, thousands of chemicals have been synthesized 

and introduced into the environment. About 1.1 billion 

pounds of pesticides are used annually in the United 

States. Agricultural uses of pesticides (herbicides, 

insecticides, and fungicides) have increased from 

190 million pounds of active ingredient in 1964 to an 

estimated 811 million pounds in 1993 (Larson and others, 1997). Although pesticide use results in increased 

crop yields by controlling weeds and other nuisance 

organisms, the occurrence of pesticides in surface 

waters (especially at elevated concentrations) warrants 

concern because of their potential toxicity to humans 

and aquatic life. In addition to agriculture, pesticides 

also are commonly used in forestry, transportation 

(weed control along roadsides and railways), urban 

and suburban areas (control of pests in homes, buildings, gardens, lawns, and golf courses), lakes and 

streams (control of aquatic flora and fauna), and various commercial and industrial settings (Larson and 

others, 1997).

The presence of pesticides at low concentrations 

in the Nation’s surface waters has been recognized for 

several decades (Larson and others, 1997; U.S. Geological Survey, 1997), and in 1994, the U.S. Geological Survey (USGS) began an assessment of water 

quality in the upper Tennessee River Basin (UTEN) as 

part of the National Water-Quality Assessment 

(NAWQA) Program. One of the objectives of the 
2 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

NAWQA Program is to describe the presence and distribution of pesticides in the environment. In many 

streams across the Nation, some pesticides exceed 

water-quality criteria for seasonal periods, but annual 

average concentrations seldom exceed regulatory standards for drinking water. Nationwide, the highest levels of pesticides in surface water occur as seasonal 

pulses lasting from a few weeks to several months, 

although generally less than 2 percent of the annual 

amount of pesticides applied to agricultural land is 

transported to streams (Larson and others, 1997). Herbicides are the most common type of pesticide present 

in streams within agricultural areas. Insecticides are 

usually detected at higher concentrations in urban 

streams than in agricultural streams (U.S. Geological 

Survey, 1999).

In the UTEN, pesticides are widely used to control insects and nuisance vegetation such as weeds and 

grasses for agriculture, lawn care, and golf course and 

right-of-way maintenance. The transport and fate of 

pesticides in streams strongly depends on the water 

solubility of the pesticides. Water solubility determines how easily pesticides wash off soil and crop residues and how readily they leach through the soil 

(Goolsby and Pereira, 1995). Some of the more persistent pesticides have been banned by the U.S. Environmental Protection Agency (U.S. EPA) for use in the 

United States, but their residues remain in the environment.

Even though pesticides are applied to specific 

areas, they can be transported to other parts of the 

environment and pose a threat to nontarget organisms. 

Most pesticides currently used on crops grown in the 

UTEN, such as corn and soybeans, are water soluble 

and enter the aquatic system predominantly in the dissolved state. Despite the widespread application of 

pesticides in the UTEN, limited information is available on the occurrence and temporal variability of pesticide concentrations in surface waters in the basin.

Purpose and Scope

The purpose of this report is to describe the seasonal and spatial variability of pesticides in streams in 

the UTEN. This report is based on two sets of data: 

one set of 362 samples collected at 13 fixed surfacewater sampling sites in the UTEN from March 1996 

through June 1999, and a separate set of 61 samples 

collected at additional stream sites throughout the 

UTEN during the springs and summers of 1996, 1997, 

and 1998. Water samples were analyzed for 77 pesticides and 8 pesticide-degradation byproducts. Evaluation of water-quality conditions in the UTEN included 

analyses of the presence and spatial distribution of 

pesticides and analyses of variations of detection frequencies and concentrations of pesticides in surface 

waters as related to land use, pesticide use, and seasonal changes. 

Study Area

The UTEN is located in the Southeastern United 

States and drains an area of about 21,400 mi2

, which 

includes the entire drainage of the Tennessee River 

and its tributaries upstream of the USGS gaging station at Chattanooga, Tenn. The UTEN includes parts 

of Tennessee (11,500 mi2

), North Carolina 

(5,480 mi2

), Virginia (3,130 mi2), and Georgia 

(1,280 mi2

); and includes parts of the Valley and 

Ridge, Blue Ridge, and Cumberland Plateau section of 

the Appalachian Plateaus Physiographic Provinces 

(fig. 1). The Valley and Ridge Physiographic Province, 

which composes about 58 percent of the UTEN, is a 

long narrow belt divided into folded bedrock terrain of 

low rolling hills and karst formations, and highly 

faulted terrain characterized by high angle thrust faulting that has resulted in 300- to 500-ft ridges separated 

by narrow valleys (DeBuchananne and Richardson, 

1956). Topography dictates land use in the UTEN; 

most of the agricultural land is located in the stream 

valleys, on benches, and on more gently rolling areas 

of the Valley and Ridge Physiographic Province. The 

Blue Ridge Physiographic Province accounts for about 

35 percent of the UTEN and includes rugged terrain, 

such as the Great Smoky Mountains. The Blue Ridge 

Physiographic Province is characterized by dense, 

massive granitic bedrock containing little water except 

where extensively faulted and fractured. The Cumberland Plateau section of the Appalachian Plateaus Physiographic Province composes about 7 percent of the 

UTEN and is characterized by mostly horizontal 

Pennsylvanian-age sandstones, shales, and coal underlain by Mississippian-age shales and carbonate rocks.

In the UTEN, forests cover about 67 percent of 

the basin. Much of this forested land lies within five 

national forests, four of which are located within the 

Blue Ridge Physiographic Province. Agriculture 

accounts for about 27 percent of the land use in the 

UTEN; of this 27 percent, pastureland accounts for 

about 24 percent and cropland accounts for about 
Introduction 3

3 percent. Corn, soybeans, winter wheat, tomatoes, 

burley tobacco, and hay are the main crops (U.S. 

Department of Agriculture, 1999). Other land uses in 

the UTEN include urban areas (4 percent) and waterbodies (2 percent).

The climate in the UTEN is characterized by 

short, wet winters and long, hot summers. The growing season in the UTEN averages about 200 days. In 

general, precipitation in the UTEN increases as elevation increases (the crest of the Great Smoky Mountains receives more than 100 in/yr). Precipitation 

decreases from south to north within the study unit. 

Elevations in the UTEN range from 621 ft above 

NGVD of 1929 at the Chattanooga, Tenn., gaging station to 6,684 feet at Mount Mitchell, N.C., which is the 

highest point in the Eastern United States (fig. 2). 

Each major subbasin in the UTEN has distinct 

climatic and runoff characteristics with average annual 

precipitation ranging from about 45 in/yr for the Holston River Basin to about 60 in/yr for the Little Tennessee River Basin, which is the highest average 

rainfall for any basin of similar size in the continental 

United States, excluding Puget Sound. The drainage 

basins of nine major tributaries (fig. 1)—Clinch, Powell, Emory, French Broad, Nolichucky, Pigeon, Hiwassee, Holston, and Little Tennessee—make up about 

86 percent of the UTEN. The flows from these tributaries account for about 85 percent of the annual mean 

discharge of 35,890 ft3

/s at the Tennessee River at the 

Chattanooga, Tenn., gaging station. These nine tributaries drain into the Tennessee River, which is 

impounded for almost its entire length through the 

UTEN.

The most prominent surface-water features of 

the UTEN are the tributary and main-stem reservoirs 

constructed and maintained by the Tennessee Valley 

Authority (TVA). Four main-stem reservoirs (with a 

combined capacity of 3.1 million acre-feet of storage) 

are primarily flow-through systems that provide power 

generation and maintain navigational depths. Seventeen tributary reservoirs provide flood storage and 

power generation and have a combined storage capacity of 10 million acre-feet. Seventeen privately owned 

and operated reservoirs also are located in the basin.

In 1990, the population of the UTEN was about 

2.4 million people, of which about 1.5 million resided 
4 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

9

in the four major urban areas of Chattanooga and 

Knoxville, Tenn., Asheville, N.C., the Tri-Cities area 

of Kingsport and Johnson City, Tenn., and Bristol, 

Tenn./Va. (fig. 2). The major urban centers in the 

UTEN are adjacent to reservoirs or major rivers.

The UTEN is characterized by an abundance of 

surface-water resources that usually meet existing 

guidelines for drinking-water supply, recreation, and 

protection of aquatic life. In 1995, withdrawals of surface water totaled about 4.9 billion gallons of water 

per day, of which 3.8 billion gallons per day was used 

for thermoelectric power generation. Of the nonthermoelectric water use, the greatest surface-water withdrawals were for commercial and industrial uses 

(59 percent) and public supply (24 percent). Public 

water-supply systems in the UTEN provide drinking 

water for an estimated 2 million people; 1.6 million 

(79 percent) of these people are served by public 

water-supply systems that receive their water from 

surface-water sources.

Degradation of surface-water quality is a concern to resource managers and environmental scientists. The UTEN contains greater aquatic biodiversity 

than most areas of similar size in the continental 

United States. For example, the upper Clinch and 

Powell River Basins are home to more than 300 globally rare species including the most diverse freshwater mussel fauna in the world. Water-quality 

impairment in the UTEN generally stems from pointsource industrial activities and nonpoint-source inputs 

from agricultural, forestry, and mining activities (Denton and others, 2000). In the free-flowing streams of 

the UTEN, nonpoint sources of nutrients, coliform 

bacteria, pesticides from agricultural areas, and sedimentation resulting from agricultural, mining, and 

construction activities are serious concerns. The clearing of riparian zones for cattle access to rivers has 

adversely affected bank stability and the aquatic biota 

diversity of the area (Denton and others, 2000). Urban 

effects of most concern are related to aging or malfunctioning sewerage systems. The increased use of 

pesticides and other compounds in suburban residential areas also warrants concern as a potential threat to 

surface-water quality. 

Study Design

Surface-water quality in the UTEN was 

assessed to determine the presence and distribution of 

pesticides in the water column. Each study-unit investigation complied with guidelines within the framework of the national study design for the NAWQA 

Program, yet was afforded flexibility to customize 

efforts to address important local water-quality issues. 

The sampling strategy in the UTEN study was 

designed to characterize the spatial and temporal distribution of pesticides in relation to hydrologic conditions, seasonal changes, land use, and contaminant 

sources.
Introduction 5

Selection of Sampling Sites and Sampling 

Frequency

Stream sampling sites in the UTEN were 

selected to assess the spatial and seasonal variability 

of selected pesticides in subbasins consisting of mixed 

land use and different mixtures of agricultural cropland. The assessment of pesticides in streams focused 

mainly on seven tributaries—the Clinch, Emory, 

French Broad, Holston, Nolichucky, Pigeon, and Powell Rivers—to the Tennessee River and mostly 

upstream of three major reservoirs (Norris, Douglas, 

and Cherokee Lakes). About 60 percent of the herbicide use in the UTEN occurs in these subbasins. These 

tributaries drain about 47 percent of the total area and 

account for about 42 percent of the mean annual discharge of the UTEN.

Thirteen fixed stream sampling sites were 

selected to assess the effects of physiographic settings 

and a variety of land uses on surface-water quality 

(table 1). The sampling strategy at these 13 sites was 

designed to assess seasonal variation in distribution 

and presence of pesticides. Water samples were collected monthly at the French Broad River, Clinch 

River, Clear Creek, Big Limestone Creek, Copper 

Creek, Guest River, Middle Fork Holston River, and 

two sites on the Nolichucky River; bimonthly at the 

Holston and Tennessee Rivers; and quarterly at the 

Powell and Pigeon Rivers (table 1). In 1996, the sampling frequency at three sites (Big Limestone Creek, 

Copper Creek, and Nolichucky River near Lowland) 

was increased to weekly sampling during the growing 

season (March through October) to increase understanding of the fate of pesticides during the application 

period. These three sites drain the largest percentage 

of agricultural land of the 13 sites in the study [Big 

Limestone Creek (83 percent), Copper Creek (51 percent), Nolichucky River (38 percent)] and are referred 

to as “agricultural sites” in the remainder of this 

report. 

In addition to the routine sampling at the 13 

fixed sampling sites, 61 stream sites (fig. 2) were sampled once to evaluate the spatial distribution of pesticides in various subbasins in the UTEN (full site 

names and site descriptions are given in appendix A). 

A different set of sites was sampled each year (1996-

98) in the spring or early summer to correspond with 

the period of peak application of agricultural pesticides and stable, low streamflow conditions. The spatial sampling in 1996 focused on the Clinch, Powell, 

and Emory River Basins; in 1997, on the French Broad 

and Nolichucky River Basins; and in 1998, on the Holston River Basin. Five samples were collected from 

selected streams in other subbasins to address topical 

issues related to water quality and ecological assessments of these streams.

Field and Laboratory Methods

Water-quality samples were collected using 

established NAWQA protocols (Shelton, 1994), which 

require the use of noncontaminating (Teflon and stainless steel) sampling equipment and quality-assurance 

sampling. Depth-integrated subsamples were collected 

using the equal-width increment (EWI) sampling 

method, which specifies sampling at equally spaced 

verticals across the stream by using either the 

US DH-81 or US D-77 sampler as described by 

Edwards and Glysson (1988) and Shelton (1994). Both 

samplers held Teflon sample bottles, and all other 

parts that contacted water samples were Teflon. The 

samples were split into equal aliquots using a Teflon 

cone splitter (Capel and others, 1995). Water samples 

were filtered at the sites through 0.7-micrometerdiameter pore-size baked glass-fiber filters to remove 

suspended particulate matter, and were stored in baked 

amber glass bottles. 

The water samples were processed through a 

solid-phase extraction (SPE) cartridge either in the 

field or at the USGS National Water Quality Laboratory (NWQL) within 4 days of collection using techniques described by Sandstrom and others (1992). 

Samples (bottles or SPE cartridges) to be analyzed at 

the NWQL were shipped on ice at approximately 

4 degrees Celsius. The SPE method uses bonded silica 

packed into an extraction column, which absorbs specific organic compounds. These compounds subsequently are removed from the extraction column at the 

NWQL by use of a solvent.

Samples were analyzed for 77 pesticides and 8 

pesticide metabolites by using either capillary-column 

gas chromatography/mass spectrometry (GC/MS) with 

selected-ion monitoring (Zaugg and others, 1995) or 

high-performance liquid chromatography (HPLC) 

(Werner and others, 1996) (table 2). The GC/MS 

method was used for pesticide analyses of 26 herbicides including the triazines and amides, 17 insecticides including the organophosphates, and 4 

metabolites. The HPLC method was used to analyze 

samples for 28 herbicides including the chlorophenoxy acids, 6 insecticides (mostly carbamates), and 4 

pesticide metabolites.
6 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

1 Sites sampled bimonthly.2 Sites sampled quarterly.3 Sites sampled monthly.4 Sites sampled weekly during 1996 growing season.

Table 1. Fixed sampling sites in the upper Tennessee River Basin study area[mi2, square mile; GC/MS, gas chromatography/mass spectrometry (analysis for 47 pesticides); HPLC, high performance liquid chromatography (analysis for 38 pesti

a result of low frequency (less than 1 percent) of detections of analytes from this method]

Site 

number 

(fig. 2)

USGS station name

USGS 

station 

number

Drainage 

area

 (mi2)

Watershed 

classification

Number of 

samples 

collected

Collection 

period

Laboratory 

method

GC/MS *HPLC Fore

1 Tennessee River at Chattanooga, Tenn.1 03568000 21,400 Mixed 12 6 5/96-2/98 67.4 2 Pigeon River near Newport, Tenn.2 03461500 666 Forest/industrial 6 4 4/96-1/98 80.3 3 French Broad River near Newport, Tenn.3 03455000 1,858 Forest/agriculture/

urban

28 12 4/96-3/98 75.4 

4 Nolichucky River near Lowland, Tenn.3, 4 03467609 1,687 Agriculture/forest 66 36 3/96-6/99 57.8 5 Clinch River above Tazewell, Tenn.3 03528000 1,474 Forest/agriculture 27 12 4/96-5/98 69.8 6 Powell River near Arthur, Tenn.2 03532000 685 Forest/agriculture 5 4 5/96-10/97 65.3 7 Holston River at Surgoinsville, Tenn.1 03490500 2,874 Mixed-industrial/

agriculture

13 6 4/96-7/98 63.6 

8 Clear Creek at Lilly Bridge near Lancing, 

Tenn.3

03539778 170 Forest 20 0 3/97-9/98 69.4 

9 Big Limestone Creek near Limestone, 

Tenn.3, 4

03466208 79.0 Intensiveagriculture 62 35 3/96-6/99 15.0 

10 Nolichucky River at Embreeville, Tenn.3 03465500 805 Forest/mining 17 10 3/96-1/98 85.1 11 Copper Creek near Gate City, Va.3, 4 03526000 106 Intensiveagriculture 50 34 3/96-2/98 47.1 12 Guest River near Miller Yard, Va.3 03524550 100 Mining/urban 28 13 6/96-5/98 79.2 13 Middle Fork Holston River at Seven Mile 

Ford, Va.3

03474000 132 Mixed agriculture/

urban/forest

27 12 4/96-7/98 69.2 
Introduction 7

Table 2. Pesticides and pesticide metabolites analyzed in samples collected from streams in the upper Tennessee 

River Basin, March 1996 through June 1999 

[Bold-faced pesticides were detected; Italicized pesticides are metabolites; GC/MS, gas chromatography/mass spectrometry; HPLC, high 

performance liquid chromatography (discontinued after February 1997)]

Herbicides Insecticides

GC/MS HPLC GC/MS HPLC

Acetochlor Acifluorfen Azinphos-methyl Aldicarb

Alachlor Bentazon Carbaryl Aldicarb sulfone

Atrazine Bromacil Carbofuran Aldicarb sulfoxide

Benfluralin Bromoxynil Chlorpyrifos Esfenvalerate

Butylate Chloramben p,p'- DDE 3-Hydroxycarbofuran

Cyanazine Chlorothalonil

(used as a fungicide)

Diazinon Methiocarb

Dacthal Clopyralid Dieldrin Methomyl

Deethylatrazine 2,4-D Disulfoton 1-Naphthol

2,6-Diethylaniline Dacthal monoacid Ethoprop Propoxur

EPTC 2,4-DB Fonofos

Ethalfluralin Dicamba alpha-HCH

Linuron Dichlobenil Lindane

Metolachlor Dichlorprop Malathion

Metribuzin 4,6-Dinitro-o-cresol Parathion

Molinate Dinoseb Parathion methyl

Napropamide Diuron cis-Permethrin

Pebulate Fenuron Phorate

Pendimethalin Fluometuron Propargite

Prometon MCPA Terbufos

Propachlor MCPB

Propanil Neburon

Propyzamide Norflurazon

Simazine Oryzalin

Tebuthiuron Oxamyl

Terbacil Picloram

Thiobencarb Propham

Triallate Silvex

Trifluralin 2,4,5-T

Triclopyr
8 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

Pesticide concentrations were reported by the 

NWQL with appropriate qualifiers to reflect analytical 

limitations. Laboratory results were reported as “less 

than” when a pesticide was either not detected or not 

present at a concentration identifiable or measurable 

by the NWQL analytical procedures. When the presence of a pesticide in the sample was detected and 

quantified, but with low analytical confidence, the 

reported value was labeled as an estimated value. For 

statistical purposes, estimated concentrations were 

included in all analyses and considered to be the same 

as non-estimated concentrations.

Quality Control

The quality of data collected and the validity of 

any interpretation cannot be evaluated without qualitycontrol data. Quality-control samples are used to quantify data accuracy, precision, and the presence of any 

field or laboratory contamination and analytical bias 

(Rinella and Janet, 1998). In addition to the regular 

water samples, a series of quality-control samples 

including field blanks, replicates, and field-matrix 

spike samples were collected and processed throughout the study period to evaluate the reliability and 

reproducibility of the data. About 15 percent of the 

water samples collected were quality-control samples. 

Field-blank samples were processed prior to 

processing the regular water samples. Field blanks 

were processed by passing a volume of organic 

contaminant-free deionized water through all sampling 

equipment. Results of the field-blank samples indicated that no systematic contamination occurred during sample collection and processing. Pesticides were 

detected in only 4 of 22 field-blank samples. The 

insecticide p,p'-DDE was detected in two of the four 

samples; the herbicide atrazine was detected in a third 

sample. The insecticide chlorpyrifos (0.004 μg/L) and 

the herbicide pendimethalin (0.006 μg/L) were 

detected in the fourth field blank. 

Sample replicates provide information to estimate the precision of concentration values determined 

from the combined sample-processing and analytical 

scheme and to evaluate the consistency of target analytes detected and quantified. The regular and replicate 

samples were collected simultaneously. Each replicate 

sample was an aliquot of the regular water sample 

from the cone splitter, and was processed immediately 

following the primary cone-split sample using the 

same equipment and identical processing and handling 

procedures as the regular water samples. Of the 21 sets 

of replicate samples, 100 of the 112 (89 percent) pesticide detections occurred in the regular and the replicate samples. Of the 100 paired sample detections, 

concentrations for 30 pesticide detections were identical for the regular and replicate samples—the average 

difference in concentrations for the other 70 paired 

detections was 0.001 μg/L. Five detections in the regular samples were not detected in the paired replicate 

samples; and seven pesticides detected in the replicate 

samples were not detected in the paired regular samples. All 12 unpaired pesticide detections were low 

concentrations and were reported as estimated values. 

Ten of these estimated values were actually below the 

laboratory minimum reporting level (MRL). One 

unpaired detection was equal to the MRL, and another 

unpaired detection was 0.001 μg/L above the MRL.

Field-matrix spikes are used to assess recoveries 

and assist in evaluating the precision of results for the 

target analytes in different matrices. Field-matrix 

spikes were prepared by adding a standard spike solution, provided by the NWQL, to a replicate sample 

processed in the same way as the regular water samples. A separate matrix-spike sample for each of the 

two pesticide analytical methods (GC/MS and HPLC) 

was prepared, stored, and shipped to the NWQL. Thirteen spiked replicate samples were analyzed for the 

GC/MS pesticides, and 4 spiked replicate samples 

were analyzed for the HPLC pesticides. The mean percent recoveries for most of the GC/MS pesticides 

ranged from 97 to 125 percent. The mean percent 

recoveries for most of the HPLC pesticides detected in 

this study ranged from 64 to 87 percent. These results 

indicate that the HPLC analytical method provides a 

more conservative estimate (biased low) of pesticide 

concentrations and detection frequencies.

Estimated Pesticide Use in the Study Area

For the UTEN study area, pesticide-use data 

were derived from county-based crop acreage data 

obtained from the 1992 Census of Agriculture (U.S. 

Department of Agriculture, 1999) and from State-level 

estimates of pesticide-use rates for individual crops 

compiled by the National Center for Food and Agricultural Policy (NCFAP) from information collected 

by State and Federal agencies over a 4-year period 

(1991-93 and 1995) (Thelin and Gianessi, 2000). 

County crop acreages were combined with the State 

use coefficients developed by NCFAP to calculate 

county-level pesticide usage by pesticide and crop. An 
Introduction 9

area-weighting factor was used to determine the estimated acreage treated with pesticides and the amount 

of pesticide applied in counties that were not entirely 

contained within the study basin (U.S. Geological Survey, 1998). Significant amounts of pesticides also are 

applied in forested, urban, and suburban areas (lawns 

and golf courses), for forestry, transportation (weed 

control along roadways and rights-of-way), aquatic 

uses (control of algae and other aquatic fauna and flora 

in lakes), and various commercial and industrial uses; 

however, reliable data for these uses were not available.

Agriculture accounts for about 75 percent of 

total pesticide use in the United States (U.S. Geological Survey, 1997). Of the 15 herbicides with the highest agricultural use in the UTEN, 11 were analyzed as 

part of the UTEN study. Eight of the 15 insecticides 

most heavily used in the UTEN were analyzed in the 

UTEN study. In contrast, chlorothalonil was the only 

fungicide among the 15 most heavily used fungicides 

that was analyzed in the UTEN study (table 3). 

The largest applications of herbicides to agricultural land in the UTEN are on field crops such as corn, 

tobacco, soybeans, and tomatoes, and on pasture and 

hay fields. The herbicide 2,4-D, the most heavily used 

herbicide by weight in the UTEN, is applied to pasture, hay, and alfalfa, which combined account for 

90 percent of the agricultural acreage in the UTEN. 

Atrazine is the second most heavily applied herbicide 

by weight, accounting for about 20 percent of the estimated herbicide use. Atrazine is a pre- and postemergent herbicide used for the control of most annual 

grasses and broadleaf weeds. Generally used in combination with other herbicides, atrazine is applied to a 

variety of crops including corn and sorghum, which 

accounts for about 4 percent of the agricultural acreage in the UTEN. Alachlor and metolachlor, preemergent herbicides used on corn, soybeans, and other 

crops for the control of broadleaf weeds and grasses, 

were applied at the third and fourth highest rates in the 

UTEN, respectively (table 3). 

Insecticides with the highest agricultural use in 

the UTEN are oil, acephate, chlorpyrifos, carbaryl, 

 Table 3. Pesticides most commonly used for agriculture in the monitored part of the upper Tennessee River 

Basin, 1992

[Bold-faced pesticides were analyzed in the upper Tennessee River Basin study area; listed in order of estimated total pounds of active ingredient 

applied in 1992; data from Thelin, 1999]

 Herbicides Insecticides Fungicides

2,4-D 93,900 Oil 242,000 Methyl bromide 321,000

Atrazine 56,500 Acephate 63,300 1-3-D 317,000

Alachlor 25,500 Chlorpyrifos 60,200 Captan 103,000

Metolachlor 24,900 Carbaryl 30,200 Ziram 68,100

Pebulate 22,000 Formetanante 15,900 Sulfur 55,400

Pendimethalin 17,000 Azinphos-methyl 13,000 Chloropicrin 32,500

Simazine 13,000 Fenamiphos 12,100 Mancozeb 24,600

Butylate 11,800 Carbofuran 11,300 Metalaxyl 19,800

Napropamide 8,750 Aldicarb 9,620 Thiran 17,800

Glyphosate 8,000 Methomyl 9,450 Copper 9,580

Isopropalin 7,410 Dimethoate 8,210 Chlorothalonil 8,410

Cyanazine 6,840 Ethoprop 7,490 Dodine 8,370

Benfluralin 5,930 Terbufos 7,400 Maneb 6,310

Paraquat 5,100 Phosmet 6,400 Metiram 5,160

Diphenamid 4,700 Endosulfan 4,080 Thiophanate methyl 3,360
10 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

formetanante, azinphos-methyl, fenamiphos, and carbofuran (table 3). Of these eight insecticides, chlorpyrifos, carbaryl, azinphos-methyl, and carbofuran 

were analyzed in the UTEN water samples. Oil solutions are oil concentrates, pesticides diluted with oil, 

or dilute, ready-to-use oil-based preparations. Petroleum or fuel oils are used as household insecticides 

and as dormant sprays to control a variety of insects, to 

inhibit egg development, and to control mosquito larvae. In the UTEN, acephate and fenamiphos primarily 

are used to control a variety of insects that plague 

tobacco crops; acephate also is used on a variety of 

vegetables. Chlorpyrifos is used to control pests on 

agricultural crops such as tobacco, corn, alfalfa, and 

apples; and for nonagricultural uses on lawns, in 

homes, and in stables for the control of soil insects and 

household pests such as ants, cockroaches, and flies. 

Chlorpyrifos is the active ingredient in Dursban, 

which is used in the Southeastern United States to control fire ants. Formetanante is used to control pests primarily on fruit crops such as apples and peaches. 

Carbaryl and carbofuran are carbamates that have a 

variety of agricultural and domestic uses. Carbaryl, 

used in suspension with oil, is applied on corn, pasture, and forest. Carbofuran is used to control various 

soil and foliar pests in field corn and soybeans, and to 

control nematodes and foliage-feeding insects on 

tobacco. Estimates of insecticide use (table 3) do not 

include these nonagricultural uses.

PESTICIDES IN STREAMS OF THE UPPER 

TENNESSEE RIVER BASIN

The presence and frequency of detection of 77 

pesticides and 8 pesticide metabolites at 13 fixed sites 

in the UTEN were evaluated. Pesticide detection frequencies in streams in the UTEN are compared to 

detection frequencies in streams throughout the 

Nation. Pesticide concentrations are evaluated to 

determine if concentrations are related to land use or 

seasonal changes. In addition, pesticide data collected 

at 61 spatial-analysis sites (sampled once) are compared with detection frequencies and pesticide concentrations at the 13 fixed sites that were sampled at 

regular intervals (usually monthly) to determine 

whether the fixed sites are representative of conditions 

throughout the UTEN.

Pesticides Detected in Streams

Of the 85 pesticides monitored during the study, 

22 pesticides (15 herbicides and 7 insecticides) and 2 

pesticide metabolites were detected at concentrations 

greater than 0.01 μg/L (table 4). The herbicides 

detected most frequently at concentrations greater than 

0.01 μg/L included atrazine (59 percent), tebuthiuron 

(41 percent), the metabolite deethylatrazine (31 percent), metolachlor (24 percent), simazine (17 percent), 

and prometon (6.4 percent) (fig. 3; table 4). The insecticides detected most frequently at concentrations 

greater than 0.01 μg/L included carbaryl (6.1 percent), 

diazinon (1.9 percent), carbofuran (1.7 percent), and 

chlorpyrifos (1.1 percent). A threshold concentration 

of 0.01 μg/L was used to calculate detection frequencies among the 85 pesticides because of different laboratory MRLs for several of the pesticides. Five 

additional herbicides (alachlor, DCPA, terbacil, trifluralin, and molinate) were detected but at concentrations less than 0.01 μg/L (table 4). Two insecticides 

[p,p'-DDE (a metabolite of DDT) and alpha HCH (a 

metabolite of lindane)] also were detected only at concentrations less than 0.01 μg/L. Using the detection 

frequencies based on the MRLs for each pesticide, 27 

pesticides (20 herbicides and 7 insecticides) and 4 pesticide metabolites were detected in stream samples.

Most samples from the 13 fixed sites had detectable levels of more than one pesticide and, therefore, 

represent a mixture of pesticides. At least one pesticide was detected in 99 percent of the 362 stream samples; two or more pesticides were detected in 

96 percent of the stream samples; and three or more 

pesticides were detected in 89 percent of the stream 

samples. The maximum number of herbicides detected 

in a single sample was 11; the maximum number of 

insecticides detected in a single sample was 3. 

Pesticides that were detected frequently in 

streams in the UTEN were generally the pesticides 

with the highest estimated use in the basin. Herbicides 

were detected more frequently than insecticides, 

which is consistent with the greater use of herbicides 

in the UTEN and the fact that herbicides are generally 

more water soluble than insecticides. Atrazine, the 

herbicide with the second highest application rate 

(56,500 pounds of active ingredient in 1992, table 3), 

was the most frequently detected pesticide in the 

UTEN. Other frequently detected herbicides were 

metolachlor, the third most heavily used, and 

simazine, (64 and 42 percent detection frequencies, 

respectively). Carbaryl was the most frequently 
Pesticides in Streams of the Upper Tennessee River Basin 11

detected (9.7 percent) insecticide and was among the 

highest in estimated use. Tebuthiuron and prometon, 

herbicides commonly used in noncropland areas, also 

were detected frequently (61 and 30 percent, respectively) in the UTEN study as was the insecticide diazinon (14 percent) (table 4); however, because reliable 

data were not available to document the magnitude of 

nonagricultural use of these pesticides, the detection 

frequencies for these pesticides could not be effectively compared to use.

The presence of pesticides in surface waters can 

be diminished by many physical and chemical processes that occur after pesticide application (Larson 

and others, 1997). For example, pesticides that rapidly 

degrade after application or that quickly sorb to soil 

particles are transported primarily during runoff. 

Many pesticides analyzed in the UTEN rarely were 

detected because of low use; however, some pesticides 

used extensively in the UTEN were detected in less 

than 10 percent of the stream samples. Herbicides such 

as 2-4-D, butylate, and pebulate were not detected, but 

were among the top eight herbicides used in the UTEN 

(table 3). Pendimethalin, which is used extensively on 

corn and tobacco in the UTEN, was detected in only 

two samples (0.8 percent) during the UTEN study. 

Alachlor, the third most commonly used herbicide in 

the UTEN, was detected in 3.3 percent of samples 

(table 4; fig. 3). Napropamide was among the highest 

used herbicides in the UTEN, but was only detected in 

4.4 percent of samples. Chlorpyrifos, the third most 

commonly used insecticide in the UTEN, was detected 

in 9 percent of samples. Chlorpyrifos has a high soil 

sorption coefficient value indicating low water 

solubility.

Detection frequencies of pesticides varied from 

site to site reflecting differences in land use in the 

upstream drainages. Atrazine or its metabolite 

(deethylatrazine) was detected in nearly 100 percent of 

samples from 10 of the 13 fixed sites. Metolachlor was 

detected frequently at sites with agriculturally dominated drainages, with the exception of a low detection 

frequency (18 percent) at Copper Creek near Gate 

City, Va. Metolachlor was detected in more than 

90 percent of the samples at six fixed sites. The lowest 

detection frequencies for atrazine and deethylatrazine 

occurred at Guest River, which drains the lowest percentage of cropland and the greatest percentage of 

urban and mining areas of any of the UTEN fixed sites 

(table 1). 
12 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

Table 4. Detection frequencies and maximum concentrations for pesticides detected in the upper Tennessee River Basin, 

1996-99—Continued

Pesticide (in 

order of detection 

frequency)

Common or trade 

name

Minimum 

reporting 

level

(μg/L)

*Detection 

frequency 

(percent)

*Detection 

frequency of 

concentrations 

≥0.01 μg/L 

(percent)

*Maximum 

concentration

(μg/L)

(date of 

sample)

MCL

(μg/L)

Lifetime 

HAL

(μg/L)

Aquatic 

life 

criterion

 (μg/L)

Herbicides

Atrazine AAtrex, Atred, 

Criazina, 

Gesaprim

0.001 93 59 2.0

5/29/96

3 3 a1.8

Deethylatrazine Degradation product 

of atrazine

0.002 90 31 0.095

7/16/97

-- -- --

Metolachlor Dual, Pennant 0.002 64 24 1.3

7/31/98

-- 70 a7.8

Tebuthiuron Perflan, Spike, 

Tebusan

0.01 61 41 0.076

6/10/97

-- 500 a1.6

Simazine Aquazine, Caliber 

91, Gesatop, 

Princep

0.005 42 17 0.214

7/31/98

4 -- a10

Prometon Pramitol, Princep 0.018 30 6.4 0.10

7/12/96

-- 100 --

Metribuzin Lexone, Sencor 0.004 4.2 3.6 0.252

6/4/97

-- 100 a1.0

Napropamide Devrinol, Naproguard0.003 4.4 2.5 0.057

6/25/96

-- -- --

Alachlor Alanox, Bronco, 

Bullet, Lasso

0.002 3.3 0.0 0.007

6/5/97

2 -- --

Diuron** DCMU, Diumate, 

Karmex

0.02 3.3 1.1 0.020

6/10/96

6/18/96

-- 10 --

Acetochlor Harness, Plus, 

Surpass

0.002 2.2 1.4 0.034

6/5/97

-- -- --

Bromacil** Bromax, Hyvar, 

Urox B, Uragan

0.035 2.2 2.2 0.32

7/26/96

-- 90 a5

2,6-Diethylaniline Degradation product 

of alachlor

0.003 1.4 0.3 0.318

4/29/97

-- -- --

DCPA Dacthal, chlorthaldimethyl0.002 1.4 0.0 0.005

8/1/96

-- -- --

Cyanazine Bladex, Fortrol 0.004 1.1 0.3 0.027

6/5/97

-- 1 a2

Dichlobenil** Barrier, Casoron, 

Norosae

0.02 1.1 0.5 0.08

10/21/96

-- -- --

Dichlorprop** 2,4 DP, Sertux 50, 

Weedone

0.032 1.6 1.6 0.18

5/29/96

-- -- --

Table 4. Detection frequencies and maximum concentrations for pesticides detected in the upper Tennessee River Basin, 1996-99

[μg/L, micrograms per liter; ≥, greater than or equal to; MCL, maximum contaminant level; HAL, health advisory level; *, summary statistics computed for the

set of 362 samples collected at fixed sites; **, pesticides analyzed in only 184 samples (all other pesticides analyzed in all 362 samples); ***, compound 

detected at spatial-analysis site only; E, estimated value; --, criteria do not exist; na, not applicable; ( ), number of criteria exceedances; RSD, risk-specific dose 

at a cancer risk level of 1 in 100,000]
Pesticides in Streams of the Upper Tennessee River Basin 13

Herbicides (cont.)

Trifluralin Treflan, Tri-4, Trific, 

Gowan

0.002 1.1 0.0 0.006

1/29/97

-- 5 a0.20

Pendimethalin Prowl, Pre-M, 

Squaron, Stomp

0.004 0.83 0.83 0.037

6/14/99

-- -- --

2,4,5-T** Hymexazol 0.035 0.5 0.5 0.05

7/25/96

-- 70 --

Molinate Ordram 0.004 0.3 0.0 0.005

6/18/96

-- -- --

Terbacil*** Counter, Sinbar 0.007 na na 0.006

4/16/97

-- 90 --

Insecticides

Diazinon D.Z.O., Basadin, 

Diazatol, Knox 

Out, Sarolex

0.002 14 1.9 0.59

7/23/96

-- 0.60 b0.08

(1)

Carbaryl Adios, Sevin, 

Carbamine, 

Denapor, Drexel

0.003 9.7 6.1 0.921

9/25/97

-- 700 a0.20

(3)

Chlorpyrifos Dursban, Brodan, 

Eradex, Genpest,

Lorsban, Profos, 

Scout

0.004 9.1 1.1 0.033

4/4/96

-- 20 c0.041

Carbofuran Carbodan, Curaterr, 

Furandan, Yaltox

0.003 3.0 1.7 0.22

5/29/96

40 -- a1.8

p,p'-DDE Degradation product 

of p,p' -DDT

0.006 1.7 0.0 0.003E

7/17/97

-- 1 RSD --

Malathion Cythion, Maltox 0.005 1.4 0.5 0.046

8/14/96

-- 200 c0.10

Lindane Acitox, gammaHCH, Lintox0.004 0.8 0.5 0.026

4/17/96

0.20 -- b0.01

(2)

Ethoprop Ethoprophos, Mocap 0.003 0.3 0.3 0.015

7/11/96

-- -- --

alpha HCH Degradation product 

of lindane, alpha

BHC, alpha Lindane, Lindol, 

Kotol

0.002 0.3 0.0 0.006

11/19/97

-- 0.06 

RSD

--

a

 Freshwater chronic water-quality criteria (U.S. Environmental Protection Agency, 2000).

b

 Great Lakes water-quality objectives (International Joint Commission United States and Canada, 1989). c

 Canadian water-quality guidelines (Canadian Council of Ministers of the Environment, 1997; Environment Canada, 2001).

Table 4. Detection frequencies and maximum concentrations for pesticides detected in the upper Tennessee River Basin, 

1996-99—Continued

Pesticide (in 

order of detection 

frequency)

Common or trade 

name

Minimum 

reporting 

level

(μg/L)

*Detection 

frequency 

(percent)

*Detection 

frequency of 

concentrations 

≥0.01 μg/L 

(percent)

*Maximum 

concentration

(μg/L)

(date of 

sample)

MCL

(μg/L)

Lifetime 

HAL

(μg/L)

Aquatic 

life 

criterion

 (μg/L)
14 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

Pesticide concentrations at all fixed sites ranged 

from 0.001 to 2.0 μg/L (table 4). Ten pesticides—atrazine, bromacil, dichlorprop, 2,6-diethylaniline, metolachlor, metribuzin, simazine, carbaryl, carbofuran, 

and diazinon—were detected in water samples at concentrations greater than 0.10 μg/L (table 4). In 47 of 

the 362 water samples collected at the fixed sites, one 

or more pesticides were detected at a concentration 

greater than 0.10 μg/L. Concentrations of atrazine 

exceeded 0.10 μg/L in 37 samples, and concentrations 

of metolachlor exceeded 0.10 μg/L in 11 samples. 

Seven water samples had concentrations of one or 

more pesticides exceeding 0.50 μg/L, and only four 

samples had concentrations of one or more pesticides 

that exceeded 1.0 μg/L.

Differences in pesticide occurrence among the 

three agricultural sites (Big Limestone Creek, Copper 

Creek, and Nolichucky River) were related to the variety of land uses and pesticide application within each 

basin. Among the agricultural sites, more pesticides 

(22) were detected in samples from the Nolichucky 

River near Lowland than from the other agricultural 

sites (fig. 4). Similarly, more pesticides also were 

detected in samples from Big Limestone Creek (17) 

than at Copper Creek (11) probably because of a 

greater percentage of agricultural land use and a 

greater variety of crops grown in the Big Limestone 

Creek Basin. Tebuthiuron, a noncropland herbicide 

often applied to powerline and road rights-of-way, was 

detected at a substantially higher frequency at Copper 

Creek than at the Nolichucky River or Big Limestone 

Creek. Detection frequencies for Big Limestone Creek 

and the Nolichucky River near Lowland were similar 

for atrazine, deethylatrazine, metolachlor, napropamide, and carbofuran (fig. 4). The most noticeable difference between these two sites was that metribuzin, 

an herbicide used to control a large number of grasses 

and broadleaf weeds on a variety of agricultural crops 

(potatoes, soybeans, and winter wheat), was detected 

in 17 percent of the samples at the Nolichucky River 

near Lowland but was not detected at Big Limestone 

Creek. Big Limestone Creek is a tributary to the Nolichucky River, and both drain the same general agriculturally dominated area; however, the Big Limestone 

Creek Basin contains a higher percentage of agricultural land use (both pasture and cropland) than the 

remainder of the Nolichucky River Basin. Agricultural 

land accounts for only about 39 percent (650 mi2) of 

the drainage upstream of the Nolichucky River site; 

however, most of the area adjacent to or directly 

upstream from the sampling site is predominantly 

agricultural.

Detection frequencies of pesticides at the three 

agricultural sites generally characterize pesticide 

detection at all fixed sites; however, some noticeable 

differences were observed (fig. 4). At the agricultural 
Pesticides in Streams of the Upper Tennessee River Basin 15

sites, 27 different pesticides were detected. Detection 

frequencies at Big Limestone Creek near Limestone 

and the Nolichucky River near Lowland were particularly high when compared to the detection frequencies 

at the other fixed sites for the pesticides (atrazine and 

metolachlor), which are commonly used for agriculture in the UTEN. Detection frequencies of pesticides 

in water samples at the Nolichucky River site more 

closely resembled detection frequencies at the other 10 

fixed sites probably because of a greater degree of 

mixed land use in the Nolichucky River Basin. Detection frequencies of pesticides for Copper Creek, however, varied considerably from the other sites, 

particularly for some of the more commonly detected 

pesticides such as metolachlor, simazine, and prometon (fig. 4). Tebuthiuron was detected more frequently 

at Copper Creek than at the other agricultural sites, 

perhaps as a result of road construction and weed control on roadway rights-of-way upstream of the sampling site. At Copper Creek, 11 pesticides were 

detected in 51 samples; however, only 4 pesticides 

were detected in more than 2 samples (less than 4 percent of samples).

Of the 47 pesticides that were analyzed in all 

samples (using the GC/MS method), 7 pesticides 

detected at the fixed sites were not detected at any of 

the sites included in the spatial analysis. Conversely, 

only one pesticide (terbacil) was detected at a spatialanalysis site that was not detected in samples collected 

at the fixed sites.

Comparisons of Detection Frequencies in the 

Upper Tennessee River Basin with Detection 

Frequencies Across the Nation

Pesticide detection frequencies for the UTEN 

were compared to a national summary of pesticide 

detections compiled by the USGS from NAWQA studies that were completed in 36 of the Nation’s major 

hydrologic basins from 1992 to 1998 and that included 

analyses of about 2,500 samples collected at 115 fixed 

sites. Pesticide detection frequencies in the UTEN 

were compared to the national averages for stream 

sites with agricultural drainages as well as for sites 

with drainages of mixed land use.

Atrazine, deethylatrazine, tebuthiuron, and 

napropamide were detected in streams of agricultural 

drainages in the UTEN more frequently than at agricultural sites included in the national summary of pesticide detections (fig. 5). Atrazine and deethylatrazine 

were detected in 99 and 98 percent of samples in the 

UTEN compared to the national average for agricultural sites of 85 and 69 percent, respectively. Tebuthiuron was detected in 62 percent of samples in the 

UTEN compared to the average of 22 percent for agricultural sites nationwide. The detection frequency for 

napropamide in the UTEN slightly exceeded the 

national average for agricultural indicator sites (6.2 

and 5.6 percent, respectively). Pesticides that were 

detected considerably less frequently in the UTEN 

streams than at the nationwide agricultural sites 
16 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

included alachlor, acetochlor, carbofuran, diazinon, 

metolachlor, metribuzin, prometon, and simazine.

Atrazine, deethylatrazine, metolachlor, tebuthiuron, and napropamide were detected more frequently 

at mixed land-use sites in the UTEN than at mixed 

land-use sites included in the national summary of 

pesticide detections (fig. 5). Atrazine and deethylatrazine were detected in 94 and 95 percent of samples 

from mixed land-use sites in the UTEN compared to 

the national average for mixed land-use sites of 83 and 

68 percent, respectively. For mixed land-use sites, 

metolachlor was detected in 84 percent of samples in 

the UTEN compared to 74 percent nationwide; and 

tebuthiuron was detected in 61 percent of samples in 

the UTEN compared to the average of 34 percent for 

mixed land-use sites nationwide. Detection frequency 

for napropamide in the UTEN slightly exceeded the 

national average for mixed land-use sites (fig. 5). 

Comparison of detection frequencies at sites with 

mixed land-use drainages in the UTEN with national 

averages reveal results similar to the agricultural sites 

with the exception of metolachlor, which was detected 

more frequently in the UTEN.

Water-Quality Standards

The U.S. EPA has established water-quality 

standards and guidelines that specify thresholds of 

concentrations of certain chemicals that have adverse 

effects on human health, aquatic organisms, and wildlife. Although the maximum contaminant levels 

(MCL) and lifetime health advisory levels (HAL) 

established by the U.S. EPA (2000) pertain to finished 

drinking water supplied by a community water system, 

values are provided with which ambient concentrations can be compared. MCLs or HALs have been 

established for 21 of the 31 pesticides and metabolites 

detected at sites in the UTEN study (table 4). Aquaticlife criteria have been established for the protection of 

aquatic organisms for short-term (acute) and long-term 

(chronic) exposures. Chronic aquatic-life criteria have 

been established for 14 of the 31 pesticides and metabolites detected at sites in the UTEN study (table 4).

Concentrations of pesticides and metabolites 

detected in streams in the UTEN generally were below 

established water-quality standards and guidelines. 

Although most of the samples collected in the UTEN 

contained detectable concentrations of one or more 

pesticides, no concentrations exceeded any human 

health standards (MCLs or HALs). Only 2 percent of 

the samples collected at UTEN sites had concentrations of one or more pesticides that exceeded the 

chronic aquatic-life criteria (fig. 6), and the exceedances were for atrazine, diazinon, carbaryl, and lindane. 

Total pesticide concentrations were computed 

by summing the concentrations of the detectable pesticides (above the MRL) for each sample in order to 

account for the presence of multiple pesticides. Total 

pesticide concentrations for samples collected at the 

fixed sites in the UTEN ranged from less than 

0.001 μg/L at Clear Creek at Lilly Bridge near Lancing, Tenn., to 3.15 μg/L for a sample with eight pesticide detections collected at Nolichucky River near 

Lowland, Tenn. The effects of pesticide mixtures on 

biota and human health are unknown; however, this is 

an area of active research, and the U.S. EPA is considering establishing health standards for combinations of 

pesticides (U.S. Environmental Protection Agency, 

1994).

SEASONAL AND SPATIAL VARIABILITY 

OF PESTICIDES IN STREAMS OF THE 

UPPER TENNESSEE RIVER BASIN

Pesticide occurrence and concentrations varied 

seasonally and spatially in the UTEN and were closely 

associated with land use and time of application. Peak 

concentrations of pesticides generally were detected 

during the spring and immediately following pesticide 

application. However, low levels (concentrations generally less than 0.10 μg/L) of pesticides were detected 

throughout the year at the fixed sites in the UTEN. 

Seasonal variability was evident for several pesticides at the 13 fixed sites. Monthly sampling for pesticides at fixed sites was conducted to characterize the 

seasonal variation of pesticides in streams in the 

UTEN. Peak concentrations occurred during the growing season (April through September) for all pesticides 

except dichlobenil, trifluralin, and alpha HCH 

(table 4). Differences in pesticide concentrations (and 

detection frequencies) between the growing and nongrowing seasons were pronounced for the French 

Broad River, Middle Fork Holston River, Clinch 

River, Clear Creek, Big Limestone Creek, and Nolichucky River. Although comparisons of median concentrations between the growing and nongrowing 

seasons indicate little change for some sites (Guest 

River and Copper Creek), maximum concentrations 

for most pesticides were detected during the growing 
Seasonal and Spatial Variability of Pesticides in Streams of the Upper Tennessee River Basin 17

season, usually during June and July following the 

application of agricultural pesticides, at all fixed sites 

(table 4). Elevated concentrations of several pesticides 

including atrazine, deethylatrazine, metolachlor, 

tebuthiuron, simazine, prometon, and chlorpyrifos 

were detected during the growing season at most fixed 

sites.

Weekly sampling at the three agricultural sites, 

where the upstream drainage areas contained large 

percentages of agricultural land, revealed that the 

highest pesticide concentrations were detected in late 

spring and early summer (fig. 7). Peak herbicide concentrations usually coincided with the first substantial 

storm following agricultural applications in the spring 

and declined to near-background levels as concentrations were diluted by the increased discharge that 

accompanied the storm. Maximum concentrations of 

herbicides were detected during May and June following the application of herbicides to farm fields and residential lawns. Of the 39 samples that contained at 

least one pesticide with a concentration greater than 

0.1 μg/L at the three agricultural sites, 36 samples 

were collected during the months of May, June, July, 

and August.

Data were collected at 61 stream sites to analyze 

the spatial variation of pesticides in 7 major subbasins 

and 3 smaller tributaries to the Tennessee River 

(fig. 2). Sampling conducted during the late springs 

and early summers of 1996, 1997, and 1998 was 

focused on low streamflow conditions in agricultural 

and mixed land-use settings. A few water samples 

were collected in urban streams that are influenced by 

industrial and municipal effluents and urban runoff. In 

1996, data collection was focused in the Clinch, Powell, and Emory River Basins; in 1997, in the Nolichucky and French Broad River Basins, and in 1998, 

in the Holston River Basin. Because of breaks in the 

sampling schedule as a result of unsuitable hydrologic 

conditions, these data do not portray nearly instantaneous, concurrent water-quality conditions, as would 

have been possible if intensive sampling had been performed over a short time period. Instead, greater 

emphasis was given to sampling under consistent 

streamflow conditions. Because of the offsets in 
18 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99
Seasonal and Spatial Variability of Pesticides in Streams of the Upper Tennessee River Basin 19

sampling dates, potential for variations of pesticide 

concentrations exists among sites; therefore, these 

variations of concentrations can be related to variation 

in timing of sampling relative to pesticide applications.

In 1996, sampling was conducted at 24 sites primarily in the Clinch, Powell, and Emory River Basins 

to evaluate spatial distribution of pesticides. Twelve 

pesticides were detected at sites in the Clinch and 

Powell River Basins; the number of pesticides 

detected per sample ranged from one to eight (fig. 8). 

Atrazine was detected most frequently (100 percent) 

in samples from the Clinch River Basin sites, and 

tebuthiuron was detected most frequently (100 percent) in samples from the Powell River Basin sites. 

Concentrations of all detected pesticides were relatively low (less than 0.10 μg/L), with the exception of 

two tebuthiuron concentrations (0.21 and 0.26 μg/L) 

in samples from the Powell River Basin.

The spatial-analysis sites sampled in the Emory 

River Basin are located within the Obed National Wild 

and Scenic River system. Two or three pesticides were 

detected at each of the five sites sampled in the Emory 

River Basin in 1996 (fig. 9). Six pesticides were 

detected at one additional site that was sampled in 

1998. Atrazine and deethylatrazine were detected in 

all samples, and prometon was detected in half of the 

samples. Metolachlor and tebuthiuron were detected in 

two samples, and diazinon was detected in one sample. Concentrations of the detected pesticides were 

generally less than 0.10 μg/L.

The French Broad River Basin sites were sampled in the spring and summer of 1997. Sampling 

began in April but was discontinued for several weeks 

because of extremely wet weather and high streamflow conditions; sampling resumed in June and was 

completed in July. Concentrations for 14 different pesticides—8 herbicides, 5 insecticides, and 1 metabolite—were detected at 20 fixed and spatial-analysis 
20 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

sampling sites. The number of pesticide detections per 

sample ranged from none detected at five sites to eight 

pesticides detected at three sites (fig. 10). The largest 

number of detections were from samples in the urban 

drainages of the Asheville, N.C., area. The only detection of the herbicide terbacil was at Mud Creek (F5 on 

fig. 10 and appendix A), which is an urban stream near 

Asheville that is influenced by industrial activity. Pesticide concentrations were generally lower in the 

French Broad River Basin than in the other study-unit 

basins with the exception of prometon, which was 

detected at a concentration of 0.16 μg/L in the French 

Broad River at Glenn Bridge Road near Arden, N.C. 

(F7 on fig. 10 and appendix A).

Nolichucky River Basin sites also were sampled 

in the summer of 1997. Concentrations for 15 different 

pesticides—10 herbicides, 4 insecticides, and 1 metabolite—were detected at 10 fixed and spatial-analysis 

sampling sites. The number of pesticides detected per 

site ranged from four to nine. The three fixed sites in 

the basin, Nolichucky River near Lowland, Tenn. 

(site 4), Nolichucky River at Embreeville, Tenn. 

(site 10), and Big Limestone Creek near Limestone, 

Tenn. (site 9), were sampled during the same time 

period as the spatial-analysis sites. Nine pesticides 

were detected at the Nolichucky River near Lowland, 

six pesticides were detected at the Nolichucky River at 

Embreeville, and five pesticides were detected at Big 
Seasonal and Spatial Variability of Pesticides in Streams of the Upper Tennessee River Basin 21

Limestone Creek in samples from this period (fig. 10). 

Atrazine and deethylatrazine were detected in all samples, and tebuthiuron and metolachlor were detected in 

8 of the 10 samples.

Eight detections occurred at the only site (Little 

Limestone Creek at Broylesville, Tenn.—site N1) that 

was not sampled during low-flow conditions in 1997. 

Little Limestone Creek was sampled several hours 

after a local thunderstorm during a declining stage 

with high turbidity conditions. Concentrations for several pesticides were elevated for this sample, including 

atrazine (0.999 μg/L), metolachlor (4.0 μg/L), acetochlor (0.393 μg/L), diuron (0.30 μg/L), and lindane 

(0.012 μg/L), which was the only exceedance of an 

aquatic-life criterion detected in stream samples from 

the spatial-analysis sites in the UTEN. The concentrations for metolachlor, diuron, and acetochlor in this 

sample were also the highest of all 423 samples (fixed 
22 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

and spatial-analysis sites) collected in the UTEN 

(1996-99); the atrazine concentration at Little Limestone Creek exceeded 99 percent of measured concentrations. The only detections of alachlor, acetochlor, 

and lindane at spatial-analysis sites in the French 

Broad and Nolichucky River Basins occurred at the 

Little Limestone Creek site. These data indicate that 

pesticide concentrations can vary significantly in 

streams during storm flows, particularly during the 

growing season.

In 1998, samples were collected at spatialanalysis sites and two fixed sites in the Holston River 

Basin. Seven different pesticides—five herbicides, one 

insecticide, and one metabolite—were detected in 

samples from the 12 sites. The number of pesticide 

detections per sample ranged from zero at Horse 

Creek near Kingsport, Tenn. (site H9, fig. 8), to four at 

the North Fork Holston River at Cloud Ford, Tenn. 

(site H7), and at two sites on Beaver Creek near Bristol, Tenn./Va. (sites H5 and H6) (fig. 8). Atrazine and 

metolachlor were the two most commonly detected 

pesticides. Atrazine was detected in 11 samples; 

metolachlor was detected in 7 samples. Pesticides 

were measured at relatively low concentrations (less 

than 0.05 μg/L) with no exceedances of human health 

or aquatic-life criteria.

At the 61 stream sites, 20 different pesticides 

were detected, and at least 1 pesticide was detected in 

89 percent of the samples collected. Median concentrations of pesticides for all spatial-analysis samples 

equaled the MRL for all pesticides except atrazine and 

deethylatrazine. Pesticide concentrations most frequently exceeding the threshold concentration of 

0.01 μg/L were atrazine (54 percent), tebuthiuron 

(41 percent), deethylatrazine (17 percent), metolachlor 

(16 percent), simazine (14 percent), and prometon 

(12 percent). Although the detection frequencies were 

lower for most pesticides at the spatial-analysis sample sites in comparison to the fixed sites, the same 

group of pesticides were most frequently detected at 

both sets of sites. Seven pesticides detected at the 

fixed sites were not detected at any of the spatialanalysis sites.

SUMMARY

The USGS conducted an assessment of pesticides in streams in the UTEN as part of the National 

Water-Quality Assessment Program. Thirteen stream 

sites were selected as fixed sampling sites to represent 

the diverse land uses, physiographic settings, and 

other drainage-basin characteristics in the UTEN, 

which includes parts of Tennessee, North Carolina, 

Virginia, and Georgia and drains about 21,400 mi2

. 

The fixed sites were sampled for pesticides at fixed 

intervals and supplemented with storm-flow samples. 

Samples also were collected at 61 additional sites in 

the major subbasins of the UTEN during the springs 

and summers of 1996, 1997, and 1998 to assess the 

spatial variation of pesticides during low flow in 

streams.

Pesticides that were detected frequently in 

streams in the UTEN were generally the pesticides 

having high estimated use in the basin. A total of 30 

pesticides were detected in 362 samples collected at 

the 13 fixed sites. Herbicides were detected more frequently than insecticides, which is consistent with the 

greater use of herbicides in the UTEN. Of the 10 most 

frequently detected pesticides, 8 were herbicides and 1 

was a metabolite of atrazine. Atrazine, metolachlor, 

and simazine, heavily used herbicides in the UTEN, 

were detected frequently in streams in the UTEN. The 

herbicides most frequently detected at concentrations 

at or greater than 0.01 μg/L were atrazine (in 59 percent of samples), tebuthiuron (41 percent), deethylatrazine (31 percent), metolachlor (24 percent), 

simazine (17 percent), and prometon (6.4 percent). 

The insecticides most frequently detected at 

concentrations at or greater than 0.01 μg/L were carbaryl (6.1 percent), diazinon (1.9 percent), carbofuran 

(1.7 percent), and chlorpyrifos (1.1 percent).

Pesticide detection frequencies also were associated with land use. Generally, the most frequently 

detected pesticides (atrazine, deethylatrazine, 

metolachlor, and simazine) were those applied to agricultural land. Detection frequencies of pesticides varied from site to site, reflecting differences in land use 

in the upstream drainages. Although Copper Creek 

near Gate City, Va., is an intensively agricultural site, 

metolachlor was detected in only 18 percent of the 

samples from the Copper Creek site. Tebuthiuron and 

prometon, which are most commonly used in noncropland areas and on pastureland, also were among the 

most frequently detected herbicides in the UTEN 

study.

Pesticide detection frequencies for the UTEN 

were compared with the national summary compiled 

by the USGS from NAWQA studies (1992-98); atrazine, deethylatrazine, tebuthiuron, and napropamide 

were more frequently detected in the UTEN study than 

in the national summary of pesticide detections for 

streams with agricultural drainages and for streams 

draining areas of mixed land use. Atrazine and 

deethylatrazine were detected in about 99 and 
References 23

98 percent of samples, respectively, in the UTEN compared to the national average of about 85 and 

69 percent, respectively, for agricultural sites. Tebuthiuron was detected in 62 percent of water samples from 

agricultural sites in the UTEN as compared to about 

22 percent of samples from agricultural sites nationwide. Pesticides that were detected considerably less 

frequently in the UTEN streams than at the nationwide 

agricultural sites included alachlor, acetochlor, carbofuran, diazinon, metolachlor, metribuzin, prometon, 

and simazine. Comparison of detection frequencies at 

sites with mixed land-use drainages in the UTEN with 

the national averages reveal results similar to the agricultural sites with the exception of metolachlor, which 

was detected more frequently in the UTEN.

Low concentrations (generally less than 

0.10 μg/L) of pesticides were detected at all 13 fixed 

sites in the UTEN. Concentrations of individual pesticides ranged from 0.001 to 2.0 μg/L. Atrazine, bromacil, dichlorprop, 2,6-diethylaniline, metolachlor, 

metribuzin, simazine, carbaryl, carbofuran, and diazinon were detected in samples at concentrations greater 

than 0.10 μg/L. In 47 of the 362 samples collected, 

one or more pesticides were detected in samples at 

concentrations greater than 0.10 μg/L. Concentrations 

of atrazine exceeded 0.10 μg/L in 37 samples, and 

concentrations of metolachlor exceeded 0.10 μg/L in 

11 samples. Seven samples had concentrations of one 

or more pesticides exceeding 0.50 μg/L, and only four 

samples had concentrations of one or more pesticides 

exceeding 1.0 μg/L. 

Peak pesticide concentrations were detected at 

the agricultural sites in late spring and early summer, 

generally coinciding with pesticide applications and 

the first substantial runoff event following pesticide 

applications. Concentrations of atrazine and metolachlor were elevated more frequently than concentrations of other pesticides, and most of the elevated 

concentrations were detected at the agricultural sites. 

The maximum pesticide concentration of 2 μg/L was 

detected for atrazine at the Nolichucky River near 

Lowland, Tenn. Agricultural land accounts for only 

about 39 percent (650 mi2) of the drainage upstream of 

this site; however, most of the area adjacent to or 

directly upstream from the sampling site is predominantly agricultural. The maximum concentration 

detected for metolachlor was 1.3 μg/L in a sample collected at Big Limestone Creek near Limestone, Tenn., 

which has a watershed that consists of about 

83 percent agricultural land. Elevated concentrations 

of several pesticides including atrazine, deethylatrazine, metolachlor, tebuthiuron, simazine, prometon, 

and chlorpyrifos were detected during the growing 

season at most fixed sites. 

Concentrations of pesticides and metabolites in 

streams in the UTEN generally were well below established water-quality criteria. Although most of the 

water samples collected in the UTEN study area contained detectable concentrations of one or more pesticides, none of the concentrations exceeded human 

health standards. Only 21 of the 31 pesticides 

detected, however, have established MCL or HAL criteria. Of the 14 pesticides detected that have established criteria for the protection of aquatic life, only 

carbaryl, lindane, diazinon, and atrazine were detected 

at concentrations exceeding the criteria in 7 of the 362 

samples collected at fixed sites. 

Spatial analysis of pesticide detections and concentrations in several of the subbasins of the UTEN 

indicated that the network of fixed sites in the UTEN 

were generally representative of conditions throughout 

the basin. The most frequently detected pesticides in 

water samples from the spatial-analysis sites were 

atrazine, deethylatrazine, metolachlor, tebuthiuron, 

simazine, and prometon. Only 1 of the 61 stream samples was collected under hydrologic conditions that 

did not represent low flow. This site, Little Limestone 

Creek at Broylesville, Tenn., was sampled several 

hours after a major storm. High concentrations of several pesticides were measured at this site, including 

one exceedance of the aquatic-life criterion for lindane. Overall, concentrations of pesticides at spatialanalysis sites were lower than at fixed sites in every 

subbasin; however, a greater number of detections 

usually occurred at sites that were influenced by urban 

or industrial land use. Of the 47 pesticides that were 

analyzed in all samples, 7 pesticides detected at the 

fixed sites were not detected at any of the spatialanalysis sites. Conversely, only one of the pesticides 

(terbacil) detected at a spatial-analysis site was not 

detected in samples collected at the fixed sites.

REFERENCES

Canadian Council of Ministers of the Environment, 1997, 

Canadian water quality guidelines (rev. ed.): Ottawa, 

Ontario, Water Quality Guidelines Task Group, Canadian Council of Resource and Environment Ministers, 

loose-leaf (originally published 1987), 23 appendixes.

Capel, P.D., Nacionales, F.C., and Larson, S.J., 1995, Precision of a splitting device for water samples: U.S. Geological Survey Open-File Report 95-293, 10 p.
24 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99

DeBuchananne, G.D., and Richardson, R.M., 1956, Groundwater resources of East Tennessee: Tennessee Division 

of Geology Bulletin 58, pt. 1, 393 p.

Denton, G.M., Vann, A.D., and Wang, S.H., 2000, The status of water quality in Tennessee 2000, 305(b) report: 

Tennessee Department of Environment and Conservation, Division of Water Pollution Control, 223 p.

Edwards, T.K., and Glysson, G.D., 1988, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey Open-File Report 86-531, 118 p. 

Environment Canada, 2001, Summary of Canadian water 

quality guidelines for the protection of aquatic life, 

accessed June 6, 2001, at http://www.ec.gc.ca/

ceqg-rcqe/water.pdf

Fenneman, N.M., and Johnson, D.W., 1946, Physical divisions of the United States: Washington, D.C., U.S. 

Geological Survey Special Map, scale 1:700,000.

Goolsby, D.A., and Pereira, W.E., 1995, Pesticides in the 

Mississippi River: U.S. Geological Survey Circular 

1133, accessed November 1999, at http://

water.usgs.gov/pubs/circ1133/pesticides.html

Hirsch, R.M., Alley, W.M., and Wilbur, W.G., 1988, Concepts for a national water-quality assessment program: 

U.S. Geological Survey Circular 1021, 42 p.

International Joint Commission United States and Canada, 

1989, Great Lakes water quality agreement of 1978 

(revised 1987), v. 2, An International Joint Commission report to the governments of the United States and 

Canada: International Joint Commission, Windsor, 

Ontario Canada, accessed March 4, 2000, at 

http://www.ijc.org/agree/quality.html

Larson, S.J., Capel, P.D., and Majewski, M.S., 1997, Pesticides in surface waters: Distribution, trends, and governing factors: Chelsea, Mich., Ann Arbor Press, Inc., 

373 p.

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

Implementation plan for the National Water-Quality 

Assessment Program: U.S. Geological Survey OpenFile Report 90-174, 10 p.

Rinella, F.A., and Janet, M.L., 1998, Seasonal and spatial 

variability of nutrients and pesticides in streams of the 

Willamette Basin, Oregon, 1993-95: U.S. Geological 

Survey Water-Resources Investigations 

Report 97-4082-C, 59 p.

Sandstrom, M.W., Wydoski, D.S., Schroeder, M.P., Zamboni, J.L., and Foremen, W.T., 1992, Methods of 

analysis by the U.S. Geological Survey National Water 

Quality Laboratory—Determination of organonitrogen herbicides in water by solid-phase extraction and 

capillary-column gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological 

Survey Open-File Report 91-519, 26 p.

Shelton, L.R., 1994, Field guide for collecting and processing stream-water samples for the National WaterQuality Assessment Program: U.S. Geological Survey 

Open-File Report 94-455, 44 p.

Thelin, G.P., 1999, County-level pesticide use estimates 

(1991-1993, 1995) in the conterminous United States, 

accessed November 1, 2001, at 

ftp://ftpdcascr.wr.usgs.gov/nsp/thelin/ncfap.html

Thelin, G.P., and Gianessi, L.P., 2000, Method for estimating pesticide use for county areas of the conterminous 

United States: U.S. Geological Survey Open-File 

Report 00-250, 62 p.

U.S. Department of Agriculture, 1999, National Agricultural Statistics Service, Census of Agriculture, Tennessee: accessed June 8, 2000, at 

http://www.nass.usda.gov/census/census92/atlas92/

html/tn.htm

U.S. Environmental Protection Agency, 1994, Atrazine, 

simazine and cyanazine; notice of initiation of special 

review: Federal Register, v. 59, p. 60412-60443, 

accessed spring 2000 at http://www.epa.gov/fedrgstr/

EPA-PEST/1994/November/Day-23/pr-54.html

U.S. Environmental Protection Agency, Office of Water, 

2000, Drinking water standards and health advisories, 

accessed October 12, 2000, at http://www.epa.gov/

waterscience/drinking/standards/dwstandards.pdf

U.S. Geological Survey, 1997, Pesticides in surface 

waters—current understanding of distribution and 

major influences: U.S. Geological Survey Fact Sheet 

FS-039-97, 4 p.

———1998, Sources and limitations of data used to produce maps of annual pesticide use, accessed June 8, 

2001, at http://ca.water.usgs.gov/pnsp/use92/

mapex.html

———1999, The quality of our nation’s waters—nutrients 

and pesticides: U.S. Geological Survey Circular 1225, 

82 p.

———2000, Pesticides in surface and ground water of the 

United States: Summary of results of the National 

Water-Quality Assessment Program, accessed September 20, 2000, at http://ca.water.usgs.gov/pnsp/allsum

Werner, S.L., Burkhardt, M.R., and DeRusseau, S.N., 1996, 

Methods of analysis by the U.S. Geological Survey 

National Water Quality Laboratory—Determination of 

pesticides in water by Carbopak-B solid-phase extraction and high-performance liquid chromatography: 

U.S. Geological Survey Open-File Report 96-216, 

42 p.

Zaugg, S.D., Sandstrom, M.W., Smith, S.G., and Fehlberg, 

K.M., 1995, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of pesticides in water by C-18 solid-phase 

extraction and capillary-column gas chromatography/

mass spectrometry with selected-ion monitoring: U.S. 

Geological Survey Open-File Report 95-181, 49 p.
APPENDIX

Appendix A 27

Appendix A. Sites sampled for spatial analysis of pesticides in the upper Tennessee River Basin, 1996-98—Continued

Site 

number USGS station name

USGS 

station 

number

Sample 

date

Drainage 

area

(square 

miles)

Land use (p

Forest Pasture Crop

Clinch River Basin (fig. 8)

C1 Little River at U.S. Highway 19 near Wardell, Va. 03522000 6-11-96 105 49.8 46.4 0C2 Big Cedar Creek below Daugherty’s Cave near Lebanon, Va. 03523080 6-10-96 86 50.6 44.6 1C3 Guest River at Esserville, Va. 03524330 5-14-96 23 78.5 13.0 0C4 Guest River at Coeburn, Va. 03524500 5-14-96 87 78.0 13.7 0C5 Blackwater Creek at Newman Ridge near Kyles Ford, Tenn. 0352763950 5-20-98 32 76.9 20.4 2

Powell River Basin (fig. 8)

P1 Powell River near Esserville, Va, 03529050 6-3-96 7 84.3 10.9 0P2 Powell River at Norton, Va. 03529075 6-4-96 11 86.1 10.4 0P3 Powell River at Blackwood, Va. 03529295 6-4-96 25 87.0 9.0 0P4 North Fork Powell River at Keokee, Va. 03530150 5-15-96 9 85.1 9.9 0P5 North Fork Powell River near Dryden, Va. 03530225 6-6-96 23 82.6 11.3 0P6 North Fork Powell River at Penningham Gap, Va. 03530550 6-12-96 89 81.7 14.0 0P7 Wallen Creek below Lone Branch near Jonesville, Va. 03531518 5-20-98 44 63.3 33.1 2P8 Indian Creek at Greers Chapel, Tenn. 03531900 5-21-98 52 57.2 39.9 2

Holston River Basin (fig. 8)

H1 North Fork Holston River near Saltville, Va. 03488000 6-13-96 223 72.9 24.7 1H2 South Fork Holston River above Damascus, Va. 03472150 7-15-98 136 66.1 30.4 2H3 Laurel Creek at Vails Mill at Damascus, Va. 03472700 7-15-98 158 86.7 11.0 1H4 Big Moccasin Creek at Collinwood near Hansonville, Va. 03489870 7-14-98 329 74.9 22.4 0H5 Beaver Creek at Bristol, Va. 03478400 7-15-98 26 31.5 48.7 8H6 Beaver Creek near Avoca below Bristol, Tenn. 03478592 7-16-98 62 35.2 36.9 5H7 North Fork Holston River near Cloud Ford, Tenn. 03490090 7-14-98 717 70.8 25.4 1H8 Reedy Creek at Gibsontown near Kingsport, Tenn. 03487595 7-13-98 53 49.9 33.0 3

Appendix A. Sites sampled for spatial analysis of pesticides in the upper Tennessee River Basin, 1996-98[USGS, U.S. Geological Survey; dates given as month-day-year]
28 Seasonal and Spatial Variability of Pesticides in Streams of the

Upper Tennessee River Basin, 1996-99 Holston River Basin (fig. 8)—Continued H9 Horse Creek at Smoky Valley near Kingsport, Tenn. 03487521 7-13-98 44 52.0 36.4 3.

H10 Big Creek near Rogersville, Tenn. 03491000 7-17-98 48 61.4 33.2 4.-- Watauga River near Watauga Point, Tenn. (not shown on fig. 8) 03483960 7-16-98 750 78.2 16.0 1.

Emory River Basin and other tributaries to the Tennessee River (fig. 9) L1 Little River at Coulter Bridge near Maryville, Tenn. 03497450 7-9-96 192 94.3 4.6 0.

L2 Little River at Rockford, Tenn. 03498863 6-24-96 300 76.7 18.5 1.W1 Whites Creek near Roddy, Tenn. 03541498 6-25-96 118 80.5 15.9 2.W2 Piney River above mouth of Sock Creek near Spring City, 

Tenn.

03542495 6-27-96 61 71.0 21.5 3.

E1 Obed River at Potters Ford near Crossville, Tenn. 03538860 7-25-96 107 49.0 39.5 7.E2 Clear Creek at Norris Ford near Jones Knob, Tenn. 03539717 7-23-96 81 60.3 29.4 5.E3 Clear Creek at Waltham Ford Bridge near Frankfort, Tenn. 03539735 7-22-96 146 68.2 24.9 3.E4 Daddys Creek at Devil’s Breakfast Table, Tenn. 03539690 7-24-96 174 60.5 29.8 4.E5 Obed River near Lancing, Tenn. 03539800 6-30-98 518 64.2 27.6 4.E6 Emory River near Lancing, Tenn. 03538580 6-26-96 92 89.3 9.8 0.

French Broad River Basin (fig. 10)

F1 French Broad River at Rosman, N.C. 03439000 7-9-97 69 92.8 4.9 1.F2 Little River at Cascade Lake Road near Little River, N.C. 0344150700 7-9-97 43 91.7 4.9 1.F3 Davidson River at Old Henderson Highway at Brevard, N.C. 0344114090 7-8-97

7-30-97

47 95.4 2.0 0.

F4 Mills River at Hopper Lane near Mills River, N.C. 0344602100 4-17-97 73 90.3 7.7 1.F5 Mud Creek at Naples, N.C. 0344700000 4-16-97 110 48.0 32.4 6.F6 Cane Creek at U.S. 25 at Fletcher, N.C. 0344766600 4-17-97 82 68.0 28.0 1.F7 French Broad River at Glenn Bridge Road near Arden, N.C. 0344776625 7-29-97 651 73.9 17.9 3.F8 South Hominy Creek at Candler, N.C. 0344834200 4-9-97 38 80.1 15.3 0.

Appendix A. Sites sampled for spatial analysis of pesticides in the upper Tennessee River Basin, 1996-98—Continued

Site 

number USGS station name

USGS 

station 

number

Sample 

date

Drainage 

area

(square 

miles)

Land use (p

Forest Pasture Cropl
Appendix A 29

French Broad River Basin (fig. 10)—Continued

F9 Hominy Creek near West Asheville, N.C. 0344878100 4-16-97 103 67.8 18.6 1F10 Swannanoa River at Biltmore, N.C. 03451000 4-15-97 130 79.3 8.5 0F11 French Broad River at Asheville, N.C. 03451500 7-30-97 944 73.2 16.6 2F12 Newfound Creek near Alexander, N.C. 0345169000 4-8-97 33 48.0 37.6 6F13 Reems Creek at New Stock Road near Weaverville, N.C. 0345182580 4-9-97 34 77.9 14.9 1F14 Flat Creek near Weaverville, N.C. 0345195390 4-10-97 25 57.4 32.2 3F15 Sandymush Creek near Volga, N.C. 0345199400 4-8-97 45 72.1 23.5 3F16 Ivy River at Marshall, N.C. 0345292005 7-8-97 154 75.1 20.1 2F17 French Broad River at Marshall, N.C. 03453500 7-31-97 1331 71.3 18.8 2F18 Big Laurel Creek near Stackhouse, N.C. 03454000 4-22-97 58 91.6 6.8 0F19 Spring Creek at NC 209 near Hot Springs, N.C. 0345458780 4-21-97 70 91.4 7.8 0

Nolichucky River Basin (fig. 10)

N1 Little Limestone Creek at Broylesville, Tenn. 03465650 7-1-97 27 15.1 64.8 10N2 Sinking Creek at WWTP near Afton, Tenn. 03466233 7-16-97 14 11.9 68.7 16N3 Little Chucky Creek near Warrensburg, Tenn. 03466698 6-25-97 39 28.3 55.7 9N4 Lick Creek near Lick Creek Mill near Baileyton, Tenn. 03466835 7-17-97 78 38.5 51.4 7N5 Bent Creek near Silver City, Tenn. 03467485 6-24-97 39 21.8 63.4 9N6 Lick Creek at Scoot Mill, Tenn. 03467300 6-25-97 262 31.1 55.6 9N7 Long Creek near Lowland, Tenn. 03468065 6-24-97 39 23.0 58.7 11

Pigeon River Basin

PI1 Pigeon River near Denton, Tenn. 03461080 7-10-96 568 82.1 11.2 1

Appendix A. Sites sampled for spatial analysis of pesticides in the upper Tennessee River Basin, 1996-98—Continued

Site 

number USGS station name

USGS 

station 

number

Sample 

date

Drainage 

area

(square 

miles)

Land use (p

Forest Pasture Crop