In cooperation with the

U.S. Environmental Protection Agency



# Pesticides in Selected Water

- Supply Reservoirs and

Finished Drinking Water, 1999

- 2000: Summary of

Results from a Pilot Monitoring Program

Open

- File Report 01

- 456

U. S. Department of the Interior

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

U.S. Geological Survey



# Pesticides in Selected Water

- Supply Reservoirs and

Finished Drinking Water, 1999

- 2000: Summary of

Results from a Pilot Monitoring Program

by

Joel D. Blomquist, Janet M. Denis

(U.S. Geological Survey)

and

James L. Cowles, James A. Hetrick, R. David Jones, and Norman B. Birchfield

(U.S. Environmental Protection Agency)

Open

- File Report 01

- 456

In cooperation with the

U.S. Environmen tal Protection Agency

Baltimore, Maryland

2001

## U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

The use of trade, product, or firm names in this report is for descriptive purposes on ly and

does not imply endorsement by the U.S. Government.

For additional information contact:

District Chief

U.S. Geological Survey

8987 Yellow Brick Road

Baltimore, MD 21237iii 

## Contents

Abstract

................................ ................................ ................................ ................................ ................................ ................................ ....... 1

Introduction

................................ ................................ ................................ ................................ ................................ ................................ 2

Purpose and scope

................................ ................................ ................................ ................................ ................................ ................ 2

Acknowledgments

................................ ................................ ................................ ................................ ................................ ................ 3

Pilot monitoring program design

................................ ................................ ................................ ................................ ............................ 3

General sampling approach

................................ ................................ ................................ ................................ ................................ 3

Description of sampling sites

................................ ................................ ................................ ................................ ............................. 5

Sampling frequency

................................ ................................ ................................ ................................ ................................ ........... 14

Methods of sample collection, analysis, and quali ty assurance

................................ ................................ ................................ ....... 17

Field methods

................................ ................................ ................................ ................................ ................................ ...................... 17

Analytical methods

................................ ................................ ................................ ................................ ................................ ............ 17

Summary o f results from the pilot monitoring program

................................ ................................ ................................ ................... 19

Gas chromatography / mass spectrometry (method 2001)

................................ ................................ ................................ .......... 20

Gas chromatography / mass spectrometry (provisional method 9002)

................................ ................................ ..................... 22

High

- performance liquid chromatography / mass spectrometry (provisional method 9060)

................................ ............... 24

Summary

................................ ................................ ................................ ................................ ................................ ................................ ... 26

Selected references

................................ ................................ ................................ ................................ ................................ .................. 28

Supplemental tables

................................ ................................ ................................ ................................ ................................ ................ 30



## Figures

1. Diagram showing g eneral on

- site sampling locations for reservoirs and community water systems.

............................. 4

2. Map showing l ocations of 12 reservo irs and community water systems included in the pilot monitoring program.

... 5

3. Graph showing s ample

- collection dates at the 12 pilot monitoring program sites in 1999 and 2000.

.......................... 16



## Tables

1. Characteristics of reservoirs and community water systems included in pilot monitoring program

............................... 6

2. Land

- use characteristics in watersheds upstream from the pilot monitoring sites

................................ .............................. 7

3. Major row

- crop groups grown in counties intersecting pilot monitoring program watersheds

................................ ........ 8

4. Order of water

- treatment stages and chemicals used during treatment for 12 community water systems included in

the pilot monitoring program

................................ ................................ ................................ ................................ ........ 9

5. Process parameters of water from 12 community water systems participating in the pilot monitoring program

........ 13

6. Summary of atrazine

- concentration distributions based on 10,000 trials of selected fixed

- frequency sampling

strategies on daily concentration data from Perry Lake, Kansas, 1993

- 94

................................ ......................... 15

7. Summary statistics of 1

- week and 2

- week sampling

- interval test scenarios using PRZMS

- EXAMS model

- predicted

atrazine and bromoxynil concentration for a small midwestern reservoir based on 1976 precipitation

records and equivalent application rates

................................ ................................ ................................ ................... 15iv

8

- 10. Summary of analysis of pesticide s in water samples from water

- supply intakes and finished water

- supply taps

using:

8. G as chromatography / mass spectrometry

— U.S. Geological Survey National Water Quality

Laboratory method 2001

................................ ................................ ................................ ............................. 21

9. Gas chromatography / mass spectrometry

— U.S. Geological Survey National Water Quality

Laboratory provisional method 9002.

................................ ................................ ................................ ....... 23

10. H igh

- performance liqui d chromatography / mass spectrometry

— U.S. Geological Survey National

Water Quality Laboratory provisional method 9060

................................ ................................ .............. 25

11

- 42. Statistical summary of pesticides and degradates detected in water samples from the:

11. W ater

- supply intake monitoring site at Canyon Reservoir near Elsinore, California

................................ ....... 31

12. F inished

- water monitoring site at Elsinore Valley Municipal Water District, Ca lifornia

................................ 32

13. W ater

- supply intake monitoring site at Eagle Creek Reservoir, Indiana

................................ ............................ 33

14. R

eservoir

- outflow monitoring site a t Eagle Creek Reservoir, Indiana

................................ ................................ 34

15. F inished

- water monitoring site at Indianapolis Water Company, Indiana

................................ ......................... 35

16. W ater

- suppl y intake monitoring site at Lake Bruin, Louisiana

................................ ................................ ............ 36

17. R

eservoir

- outflow monitoring site at Lake Bruin, Louisiana

................................ ................................ ................ 37

18. F inis hed

- water monitoring site at Tensas Water Distribution Association, Inc., Louisiana

............................ 38

19. W ater

- supply intake monitoring site at Higginsville Reservoir, Missouri

................................ ......................... 39

20. R

eservoir

- outflow monitoring site at Higginsville Reservoir, Missouri

................................ ............................. 41

21. F inished

- water monitoring site at City of Higginsville Municipal Utilitie s, Missouri

................................ ..... 42

22. W ater

- supply intake monitoring site at Tar River Reservoir, North Carolina

................................ ................... 43

23. R

eservoir

- outflow monitorin g site at Tar River Reservoir, North Carolina

................................ ....................... 44

24. F inished

- water monitoring site at Tar River Water Treatment Plant, North Carolina

................................ ...... 45

25. W ater

- supply intake monitoring site at LeRoy Reservoir, New York

................................ ................................ . 46

26. F inished

- water monitoring site at Village of LeRoy Water Department, New York

................................ ....... 47

27. W ater

- supply intake monitoring site at East Fork Lake, Ohio

................................ ................................ .............. 48

28. R

eservoir

- outflow monitoring site at East Fork Lake, Ohio

................................ ................................ ................. 49

29. F inished

- water monitoring site at Clermont Water Authority, Ohio

................................ ................................ ... 50

30. W ater

- supply intake monitoring site at Lake Arcadia, Oklahoma

................................ ................................ ....... 51

31. R

eservoir

- outflow monitoring site at Lake Arcadia, Oklahoma

................................ ................................ ........... 53

32. F inished

- water monitoring site at Edmonds Water Supply, Oklahoma

................................ .............................. 54

33. W ater

- supply intake monitoring site at Blue Marsh Reservoir, Tulpehocken Creek, Pennsylvania

.............. 55

34. F inished

- water monito ring site at Western Berks Water Authority, Pennsylvania

................................ ........... 57

35. W ater

- supply intake monitoring site at South Pacolet Reservoir, South Carolina

................................ ............ 58

36. R

eservoir

- outflow monitoring site at South Pacolet Reservoir, South Carolina

................................ ............... 59

37. F inished

- water monitoring site at Spartanburg Waterworks, South Carolina

................................ .................... 60

38. W ater

- supply intake monitoring site at Lake Mitchell, South Dakota

................................ ................................ 61

39. R

eservoir

- outflow monitoring site at Lake Mitchell, South Da kota

................................ ................................ .... 62

40. F inished

- water monitoring site at Mitchell Water Department, South Dakota

................................ .................. 63

41. W ater

- supply intake monitoring site at Lake Waxahachie, Texas

................................ ................................ ...... 64

42. F inished

- water monitoring site at City of Waxahachie Water Treatment Plant, Texas

................................ ... 65v 

## Conversion Factors

Multiply By To ob tain

mile (mi) 1.609 kilometer (km)

square mile (mi 2 ) 2.590 square kilometer (km 2 )

acre 4,047 square kilometer (km 2 )

Acre

- foot (acre

- ft) 1,233 cubic meter (m 3 )

million gallons per day (Mgal/d) 3,785 cubic meters per day(m 3 /d)

Concentrations of chemi cal constituents in water are given either in milligrams per liter (mg/L) or micrograms

per liter ( μ g/L).vi Pesticide s in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000:Summary of Results from a Pilot Monitoring Program 1 

# Pesticides in Selected Water

- Supply Reservoirs and Finished

Drinking Water, 1999

- 2000: Summary of Results from a Pilot

Monitoring Program

by Joel D. Blomquist, Janet M. Denis, James L. Cowles, James A. Hetrick,

R. David Jones, and Norman B. Birchfield

Abstract

In 1999, a pilot monitoring program was

initiated by the U.S. Geological Survey and the

U.S. Environmental Protection Agency to

provide information on pesticide concentrations

in drinking water and to assist in the

implementation of the Food Quality Protection

Act of 1996. Drinking

- water utilities that

withdrew from reservoirs were sampled because

reservoirs are vulnerable to pesticide

co ntamination, integrate pesticide loading from

their watersheds, and show smaller temporal

variations than streams. Sampling frequencies

were designed to measure long

- term mean and

short

- term peak concentrations of pesticides in

drinking water. Samples were collected quarterly

throughout the year and at weekly or bi

- weekly

intervals following the primary pesticide

application periods. Water samples were

collected from the raw

- water intake and from the

finished drinking

- water tap prior to entering the

distrib ution system. At some sites, samples were

also collected at the reservoir outflow.

Twelve water

- supply reservoirs were

sampled, ranging in size from 120 to 92,600

acre

- feet normal capacity, with contributing

watersheds ranging from 3.3 to 784 square

miles. The sites are in California, Indiana, Ohio,

Oklahoma, Louisiana, Missouri, South Carolina,

South Dakota, New York, North Carolina,

Pennsylvania, and Texas. In 1999, drought

conditions affected parts of the Eastern United States and California; therefore s ampling was

extended through 2000 at nine sites.

Analyses for pesticides in water samples were

performed at the U.S. Geological Survey

National Water Quality Laboratory in Denver,

Colorado, using three analytical methods.

Overall, these methods included 17 8 different

pesticides and degradation products. Of these,

108 compounds were detected in at least one

sample from a raw

- water intake or finished

water tap. Many of these compounds, however,

were detected in fewer than 5 percent of the

samples and at conce ntrations very near the

method reporting level. The observed detection

frequencies for raw water are similar to those

reported for 58 stream sites sampled from 1992

- 95 as part of the U. S. Geological Survey

National Water

- Quality Assessment Program.

None of the pesticides were detected in finished

water at a concentration greater than a National

drinking

- water criterion, such as a Maximum

Contaminant Level or Health Advisory Level.

Widely used herbicides including atrazine,

simazine, metolachlor, prometon, cyanazine,

2,4

- D, tebuthiuron, and acetochlor were the most

frequently detected pesticides in both intake and

finished

- water samples. Detection frequencies

for these compounds ranged from 35.6 to 96.3

percent in raw

- water samples and from 18.7 to

95.6 per cent in finished

- water samples. Four

triazine

- herbicide degradation products also

were detected in more than 60 percent of all

samples.2 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Diazinon and chlorpyrifos were the two most

frequently detected insecticides in raw

- water

samples, with 35.3 percent an d 5.3 percent

detection frequencies, respectively. Neither of

these insecticides were detected in finished

water. Malaoxon, the principal oxidative

transformation product of malathion, was

detected in 11 finished

- water samples and none

of the raw

- water sam

ples. In three of the samples

where malaoxon was detected in finished water,

the corresponding intake sample showed

measurable concentrations of malathion.

Diazoxon, the principal oxidative transformation

product of diazinon, was not included as an

analyte on any of the three methods used in this

study.



## Introduction

In 1999, the U.S. Geological Survey (USGS) and the

U.S. Environmental Protection Agency (USEPA) initiated

a pilot monitoring program to provide data on pesticide

concentrations in drinking wa ter. USEPA’s Office of

Pesticide Programs (OPP) has responsibility under the

Food Quality Protection Act (FQPA) of 1996 to assess

aggregate risk from exposure to pesticides in drinking

water based on available data. Prior to implementation of

this pilot program, however, there were few available data

sets that contained information on pesticide concentrations

in finished drinking water on a national scale, as most

available data sets generally cover only selected

compounds or local areas. USEPA’s Office of Ground

Water and Drinking Water (OGWDW) is responsible for

regulating contaminant levels in public drinking

- water

supplies under the Clean Water Act of 1999. With this

responsibility, OGWDW gathers information on the

occurrence of contaminants, includin g pesticides, in

drinking

- water supplies. The pilot program described in

this report was implemented to begin to fill this important

data gap, and to provide more information about

appropriate methods for national monitoring of pesticides

in drinking water

. Since 1986, the USGS National Water

- Quality

Assessment (NAWQA) Program has collected thousands

of streamwater and ground

- water samples for pesticide

analysis. The USGS National Water Quality Laboratory

(NWQL) has developed techniques for analysis of larg e

groups of pesticide compounds with low reporting limits.

The NAWQA data sets provide the only nationally

consistent pesticide concentration data for a large suite of compounds. OPP currently uses the NAWQA data in their

drinking

- water and aquatic

- exposur e assessments;

however, these data are not collected from public water

supplies and, therefore, may not reflect exposure to

pesticides in drinking water.

The pilot monitoring program described in this report

was designed to provide information on the occur rence of

pesticides in drinking water in a variety of geographic

settings using sampling and analytical techniques that

have been tested and used by the USGS NAWQA

Program. Sampling focused on drinking

- water utilities that

withdraw from reservoirs because reservoirs are

considered to be highly vulnerable to pesticide

contamination, integrate pesticide loading from their

watersheds, and show smaller temporal variations than

streams. Although collecting data on the occurrence of

pesticides in drinking water i s not specifically within the

objectives and current design of the NAWQA program,

the NAWQA program has the infrastructure for collecting

samples from raw and treated drinking water to meet

USEPA’s data requirement. The sampling approach

implemented in 199 9 was designed by a team of scientists

from USEPA and USGS. Because of drought conditions in

the Eastern United States and California in 1999, the pilot

program was extended though 2000 at nine of the twelve

monitoring sites.

Purpose and Scope

The purpos e of this report is to present and summarize

the data collected during the pilot monitoring program

conducted in 1999 and 2000. The report also describes the

design of the monitoring program and the broad array of

goals and objectives for this study. The p esticide

concentration data from the program are summarized for

the entire data set, and for individual monitoring sites.

The pilot monitoring program was conducted as a data

collection program to provide data for subsequent analysis

by scientists within t he USGS, the USEPA OPP and

OGWDW, and other interested parties. This report

summarizes only the raw data from this study; however,

additional analysis is required to fully meet the overall

goals of the study.Summary of Results from a Pilot Monitoring Program 3

Acknowledgments

The United States Environmenta l Protection Agency

(USEPA) Office of Pesticide Programs (OPP), the USGS

National Water

- Quality Assessment Program (NAWQA),

and the USEPA Office of Ground Water and Drinking

Water (OGWDW) provided financial support for this pilot

monitoring program. Their support and collaboration

during the planning and execution of this pilot program

are greatly appreciated.

Special thanks are extended to the management and

staff of each of the participating community water systems

who granted access to USGS staff for sa mple collection,

and provided assistance to the study team. Their

willingness to participate in this voluntary effort in the

interest of developing a better understanding of their water

system is greatly appreciated.

The contribution of many dedicated USGS personnel

throughout the country that assisted with site selection,

program design, sample collection, data management, and

analysis activities is also acknowledged. The authors also

wish to thank the staff of the USGS NWQL for

performing the laboratory a nalyses and for permitting

analysis by two new laboratory methods concurrent with

final method development and testing.



## Pilot Monitoring Program Design

The pilot monitoring program was designed as a first

step towards a long

- term goal of characterizing hu man

exposure to pesticide residues in drinking water derived

from surface

- water sources. A team of scientists from

USGS and OPP, with input from other USEPA and USGS

experts, developed the sampling approach to collect data

on the occurrence of pesticides i n drinking

- water sources

that are linked to pesticide concentrations observed in

finished drinking water. The design enables the resultant

data set to be used to support the following data

- analysis

objectives:

1) Ecological risk assessments for reservoir sy stems;

2) Analysis of the relation between sampling

frequency and the precision of estimates of peak

concentrations of pesticides in community water

systems;

3) Analysis of the concentration of pesticides in

finished drinking water in relation to source

water co ncentrations and overall water

- treatment

processes;

4) Analysis of the relation of pesticide

concentrations in reservoirs to watershed and

reservoir characteristics; and

5) Evaluation and development of watershed and

reservoir models. This study focused on smal l drinking

- water supply

reservoirs in areas with high pesticide use, and will

provide information that can be linked to the NAWQA

database on pesticide occurrence in surface water. The

analytical approach used the unique capability of the

NWQL to analyze w ater samples for a broad suite of

pesticide compounds with low levels of detection. The

results of this pilot program may be used to increase the

technical level and cost

- effectiveness of future pesticide

monitoring programs.

General Sampling Approach

A co mprehensive sampling approach was required for

the pilot program due to the number of intended uses for

the monitoring data. The primary sampling approach

specified water

- sample collection of raw water from a

Community Water System (CWS) intake and of the

finished water at the entry point to the distribution system.

These two samples, collected sequentially, provide the

basis for comparing pesticide concentrations in pre

- and

post

- treatment drinking water. CWSs supplied by

reservoirs were chosen as the focu s of this pilot effort

because reservoirs integrate pesticide loadings over time.

Pesticide concentrations in reservoirs show smaller

variations over short periods of time than free

- flowing

streams. Although residence time within a water

- treatment

facility is variable and can extend for many hours, the

small temporal variability of pesticide concentrations in

reservoirs improves the link between raw

- and finished

water samples collected at nearly the same time.

Samples were collected at the outflow of many of the

reservoirs because conditions at an intake may differ

substantially from average reservoir conditions. This was

done so comparisons could be made between the pesticide

concentrations observed at an intake with a more

representative sample reflectin g water leaving the

reservoir. Although these data are not necessary for

assessing pesticide exposure, they provide the primary

basis for ecological risk assessments and for relating

pesticide concentrations to watershed and reservoir

characteristics.

A schematic diagram for the general sampling

approach at a reservoir and a CWS is shown in figure 1.

The finished

- water sample was collected from a water tap,

representative of the treated water entering the distribution

system (labeled as sampling location “A”). In nearly all

cases, this was the tap used by the utility for routine

monitoring. In instances where a water supplier has

multiple treatment facilities, it was determined that one

facility and one tap would be selected at random and

sampled through out the duration of the program. In

practice, each facility included in the pilot program had

only one such tap. The finished

- water sample provides the

best practical measure of pesticide concentrations that the4 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: supplied population is exposed to in drinki ng water. The

lag time between final treatment and delivery to a

drinking

- water tap may be long and vary considerably

among distribution systems. Because this can allow

additional time for degradation and transformation of

pesticides, the measured levels a t the finished

- water

sampling location may be somewhat different than the

actual concentrations to which consumers are exposed.

Raw

- water samples were collected from a tap on the

intake supply line (shown in figure 1 as sampling location

“B”). When no in take tap existed, raw

- water samples

were collected from the reservoir at the intake in use at the

time of sampling. Pesticide analyses of raw

- water samples

show the pesticide occurrence in source water prior to the

effects of treatment. Raw

- water samples w ere collected in

conjunction with finished

- water samples to determine the

levels of influent concentrations at these CWSs, to permit

a general evaluation of the efficiency of water

- treatment

processes in removing residues, and to identify

transformations t hat may result from treatment. Due to

variation in retention time during the treatment process,

the raw and finished water samples are not precisely

paired. The goal of pairing the raw and finished samples

in this study is to provide a general understandi ng of the

relative impact of treatment processes on pesticide

removal and transformation, and to identify areas that may

require additional study.

A sample from the reservoir outflow (shown as

sampling site “C” in figure 1) was collected at selected

sites during each routine sampling trip, and was intended

to approximate average reservoir concentrations at the

time of sampling. This measure was designed to provide a

consistent link between observed concentrations and

reservoir and watershed characteristics. Studies have

shown that water

- quality and pesticide concentrations can

vary considerably within any reservoir system (Elkhart

and others, 1999). Vertical stratification and seasonal

mixing in deeper reservoirs have been shown to be sources

of variability,

and horizontal stratification in large

dendritic reservoirs has been shown to be another source

of variability. It is generally recognized that the intake

location for many water supplies may not be an ideal

indicator of average reservoir conditions. The reservoirs

included in this study were generally small, however, and

variations in concentrations within the reservoir are

expected to be slight. Outflow samples were chosen as the

primary measure of reservoir concentrations because they

integrate pestici

de concentrations within the reservoir

system and provide data on pesticide flux through

reservoirs and their watersheds. Several of the pilot monitoring sites had drinking

- water intakes located at or

very near the reservoir outflow. In these cases, only the

intake was sampled and the intake was assumed to be

representative of outflow concentrations. In addition,

several of the reservoirs experienced prolonged periods

without releases. Outflow samples were not collected

during these periods.



### Figure 1. General on

- site sampling locations for

reservoirs and community water

systems.Summary of Results from a Pilot Monitoring Program 5



### Figure 2. Locations of 12 reservoirs and community water systems included in the pilot monitoring

program.

Description of Sampling Sites

Each sampling site included in this s tudy consisted of a

reservoir and Community Water System. This study

focuses on small drinking

- water supply reservoirs in areas

with high pesticide use in order to test the sampling

approach in areas where pesticides are probably present.

Sampling sites we re selected from a variety of geographic

regions and included different cropping patterns in order

to assess different pesticide

- use patterns. Because this

program was implemented within the NAWQA design

structure, strong consideration was given to candida te sites

that were within existing NAWQA Study Units.

A candidate list of sites was developed from an

analysis of CWS sites from the Safe Drinking Water

Information System /Federal Version (SDWIS/FED)

(USEPA, 1998), and from recommendations from local

NAWQ A Study Units and USGS District offices. Twelve

water

- supply reservoirs, considered to be vulnerable to

pesticide contamination, were selected from the list of

candidates (fig. 2; table 1). The 12 sites are located in

California (CA), Indiana (IN), Ohio (O H), Oklahoma (OK), Louisiana (LA), Missouri (MO), South Carolina

(SC), South Dakota (SD), New York (NY), North

Carolina (NC), Pennsylvania (PA), and Texas (TX). The

primary factors considered in assessing vulnerability were

reservoir size, and estima tes of pesticide use and runoff

potential; however, no direct measure of the last two

factors was readily available for contributing watersheds

during the design process. Small reservoirs in high

pesticide

- use areas were anticipated to have high rates of

p esticide occurrence. Thus, the ideal candidate reservoirs

were mostly small reservoirs located in high pesticide

- use

areas, with a high runoff potential. Three sources of data

were used together as surrogates for watershed pesticide

use rates, including: c ounty row

- crop production, county

estimates of pesticide use, and mapped land

- cover data.

Site selection was conducted by reviewing maps and other

data for each potential CWS and reservoir to determine:

(1) whether the contributing land use was largely

agr icultural or developed, (2) the primary cropping

patterns, and (3) relative pesticide use rates for a variety of

compounds. Many candidate reservoirs were eliminated6 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 1. Characteristics of reservoirs and community water systems included in pilot monitoring

p rogram

[See page 16 for a description of sampling frequencies]

State Reservoir name Community water system Location Population

served 1

(thousands) Reservoir

capacity 2

(acre

- feet) Watershed

size

(square

miles) Sampling

frequency

CA Canyon

Reservoir Elsin ore Valley Municipal

Water District Lake Elsinore 81.1 11,867 758 Base

IN 3 Eagle Creek

Reservoir Indianapolis Water Company Indianapolis 801 24,000 170 Enhanced

LA 3 Lake Bruin Tensas Water Distribution

Association, Inc. St. Joseph 0.4

-- 21.4 Base

MO 3 H igginsville

Reservoir City of Higginsville

Municipal Utilities Higginsville 4.7 1,661 4.9 High

NY 3 LeRoy

Reservoir Village of LeRoy Water

Department LeRoy 6.3 196 3.3 Base

NC Tar River

Reservoir Tar River Water Treatment

Plant Rocky Mount 56 4 11,200 784 Base

OH 3 East Fork

Lake Clermont Water Authority Batavia 80 5 92,600 218 Base

OK 3 Lake Arcadia Edmonds Water Supply Arcadia 53 120 98.1 High

PA 3 Blue Marsh

Reservoir Western Berks Water

Authority Reading 25 22,897 175 Base

SC 3 South Pacolet

Reservoir Sp artanburg Waterworks Chesnee 1.9 22,400 414 High

SD 3 Lake Mitchell Mitchell Water Department Mitchell 13.8 8,960 579 Base

TX Lake

Waxahachie City of Waxahachie Water

Treatment Plant Waxahachie 23 6 13,500 31.3 High

1 Data obtained from Marilee Horn, U.S. Geological Survey, written commun.,1999.

2 Data obtained from National Inventory of Dams, U.S. Army Corps of Engineers, 1996.

3 Sites sampled in 1999 and 2000.

4 Jay Van Hoose, Tar River Water Treatment Plant, oral commun., 2001.

5 Eric Heiser, Clermont W ater Authority, written commun. 2001.

6 Leonard Leinfelder, City of Waxahachie, written commun., 2001.

from consideration because they are upstream from the

principal agricultural lands. Other factors considered in the

selection of sampling sites were spatial representation

across the country, integration with ongoing monitoring

efforts, and willing participation by the water

- supply

utility. Where possible, sites were selected on reservoirs

located downstream from NAWQA fixed stream

monitoring sites so that additional data could be collected

to represent the flux of pesticides into reservoirs. Several

of the sites selected have ongoing monitoring programs

within the watershed or reservoir studies. As a final check,

each site was evaluated in relation to National maps of

county pesticide

- use estimates (Thelin and Gianessi, 2000)

to determine the watershed’s representation of regional

pesticide

- use patterns. The 12 sites selected were

determined to be vulnerable to the pesticides used regionally, however, they are not necessarily the most

vulnerable sites in any given region.

During the site

- selection process, the limitations of

available National data sets for CWSs and watershed

characteristics became evident. CWS latitude

- longitude

locations were frequen tly inaccurate or unavailable in

SDWIS, and relatively little information was available that

identified the type of water body used for water supply.

Marilee Horn (U.S. Geological Survey, written commun.,

1998) supplied additional information on water

- supp ly

intakes serving populations greater than 10,000 people.

The 12 sites selected for the pilot monitoring program

include reservoirs ranging in size from 120 to 92,600 acre

ft normal capacity and watersheds ranging from 3.3 to 784

mi 2 (square miles). Wate rshed boundaries were delineated

for each of the reservoirs sampled and land

- useSummary of Results from a Pilot Monitoring Program 7

characteristics were summarized by intersecting the

watershed boundary with the 30

- m (meter) resolution

National Land Cover Dataset (NLCD) (Vogelmann,

2001). Ten of the 12 si

tes were selected to represent

agricultural land use, with percent total agricultural land

ranging from 24.4 to 94.9 percent (table 2). The CA and

OK sites were selected because urban areas were deemed

to be the predominant influence on water quality in th eir

basins. The urban area in the CA watershed has grown

considerably since the early 1990’s when the satellite

imagery, which provides the basis for the NLCD, was

collected and most of this growth has occurred near the

reservoir. The major crops grown in each of the watersheds

generally reflect national cropping patterns. Table 3

summarizes the major crop groups grown in each county

intersecting the watersheds, and uses the classifications

provided by Gilliom and Thelin (1997). These crop

classifications are based on the 1992 Census of

Agriculture (U.S. Department of Commerce, 1995) and

may differ from crops actually grown during the study

period. Many of the sites selected include areas with

substantial amounts of corn, soybeans, wheat, and

alfalfa

— four of the most widely grown crops in the

country. An effort was made to include sites that

encompass regionally important crop groups including

tobacco in NC and orchards in SC.



### Table 2. Land

- use characteristics in watersheds upstream from the pilot monit oring sites

Primary land

- use groups 1 NLCD agriculture sub

- groups,

in percent in percent State Reservoir

Agriculture Urban Forest Pasture Row crop Grass

lands Small grains

CA Canyon 28.7 8.1 60.6 2.1 13.2 10.9 2.6

IN Eagle Creek 86.3 4.6 7.5 21.2 6 5.2

LA Bruin 64.9 0.1 9.8 2.5 58.0 4.5

MO Higginsville 81.7 0.6 12.0 43.7 37.0 0.6 0.4

NC Tar River 24.4 2.4 71.5 7.8 16.6

NY Leroy 81.8 0.1 13.7 51.8 30.0

SC South Pacolet 28.9 9.9 59.7 13.0 15.9

SD Mitchell 94.9 0.4 0.4 47.7 41.7 4.5 1.0

OH East Fork 72.3 2.3 23.4 28.7 43.5

OK Arcadia 34.5 39.5 22.2 9.8 2.2 21.5 1.0

PA Blue Marsh 67.0 2.5 28.8 49.2 17.8

TX Waxahachie 84.5 0.8 11.0 51.5 20.8 11.4 0.7

1 Land

- use data from National Land Cover Dataset (NLCD) (Vogelmann, 2001).8 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 3. Maj or row

- crop groups grown in counties intersecting pilot monitoring program watersheds

[>, greater than]

State Reservoir Classification of row crops on a county basis 1

County Crop and total harvested acreage on a county basis, in

percent

CA Canyon Rive rside Wheat and other grains > 20 Alfalfa > 20

IN Eagle Creek Hamilton, Boone, Marion, Hendricks Corn > 20 Soybeans > 20

LA Bruin Tensas Corn > 20 Soybeans > 20

MO Higginsville Lafayette Corn > 20 Soybeans > 20

NY Leroy Wyoming Corn > 50

Genesee Cor n > 20 Wheat and other grains > 20 Vegetables > 10

NC Tar River Granville Tobacco > 50

Franklin, Polk, Vance Wheat and other grains > 20 Soybeans > 20

Nash Wheat and other grains > 20 Soybeans > 20 Cotton > 10

OH East Fork Clinton, Brown, Clermont Corn > 20 Soybeans > 20

SC South Pacolet Spartanburg, Greenville Corn>20 Soybeans>20 Wheat and other grains>20

SD Mitchell Sanborn Corn>20 Alfalfa>20 Soybeans >20

Jerauld Corn>20 Alfalfa>20 Wheat and other grains>20

Aurora, Davison Corn > 20 Soybe ans > 20

OK Arcadia Oklahoma Wheat and other grains > 50

PA Blue Marsh Berks, Lebanon Corn > 50

TX Waxahachie Ellis Corn > 20 Wheat and other grains > 20

1 from Gilliom and Thelin, 1997

The type of water treatment used at each of the

selected C WSs was not used as a selection criterion.

Interviews were conducted with staff from each of the

CWSs to assemble a consistent coding of the treatment

processes used at each site and a record of the chemicals

used during each step of the treatment processe s. A

summary of this information is listed in table 4.

CWSs generally use one or a combination of four basic

treatment types. These include disinfection, mixing,

flocculation, and filtration. There are several methods of

disinfecting raw water. These inclu de chlorination,

pasteurization, ultraviolet radiation, distillation, and

ozonation. There are also many types of filtration units for

treating raw water. These include micro

- filtration,

activated carbon filters, oxidizing filters, sand, and

neutralizing f ilters. Each treatment step can occur at any

point during the treatment process. The point at which it

occurs may influence how well unwanted elements such as

pesticides are eliminated from the raw water. At eight of

the sites (MO, TX, OH, CA, IN, SC, NY, and PA),

chlorine is added during pre

- disinfection. In OK, ozone is

added instead. At nine of the sites (MO, TX, OH, OK, IN,

SC, NC, NY, and PA), flocculation is followed by

filtration. In all of the states listed above, post

- disinfection occurred before storage and included the addition of

chlorine in some form. In seven of the states (OH, IN, SD,

SC, NC, NY, and PA), fluoride was also added to bring

the concentration to approximately 1 milligram per liter.

Two sites, CA and OH, underwent significant

oper ational changes during the course of the pilot

monitoring program. The CA site closed for major

renovations just prior to the intended start of sampling.

Sampling was delayed until July 1999, and continued until

December 1999, when the facility closed. Dur ing the

startup of a new facility, the treatment process may be

somewhat unstable and results may differ from those

collected while a facility is in normal operation. In March

2000, the OH site shifted from a more conventional

treatment system using powder ed activated carbon to an

advanced treatment system using granular activated

carbon (GAC).Summary of Results from a Pilot Monitoring Program 9



### Table 4. Order of water

- treatment stages and chemicals used during treatment for 12 community water

systems included in the pilot monitoring program

[GAC, granular activat ed carbon; PAC powdered activated carbon]

California Site Indiana Site Louisiana Site

Elsinore Valley Municipal

Water District Indianapolis Water

Company Tensas Water Distribution

Association, Inc.

Lake Elsinore, CA Indianapolis, IN St. Joseph, LA

C anyon Reservoir Eagle Creek Reservoir Lake Bruin

I I |

screen/pump screen/pump surface intake

I I I

Pre

- Disinfection Pre

- Disinfection Clarification

chlorine (optional) chlorine, carbon (optional) chlorine, aluminum,

aluminum salts I and soda ash add ed

I Splitter and Rapid Mix I

Rapid Mix chlorine, aluminum Filtration

cationic polymer sulfate, polymers, I

I carbon (optional), lime Reservoir

Accelerator potassium permangate I

chlorine (optional) I Distribution

non

- ionic polymer Mixing and Settl ing Basin

I I

Pre

- Chlorination chlorine, polymer, and

sodium hydroxide PAC added

I I

Dual

- Media Filters Filter Plant

I I

Post

- Chlorination fluoride, ammonia

I I

Clearwell Storage Finished Water Reservoir

I chlorine

Holding Pond I

| Distribution

Distribution10 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 4. Order of water

- treament stages and chemicals used during treatment for 12 community water

systems included in the pilot monitoring program

-- continued

Missouri Site New York Site North Carolina Site

City of Higginsville Municipal

Utilities Village of LeRoy Water

Department Tar River Water Treatment

Plant

Higginsville, MO LeRoy, NY Rocky Mount, NC

Higginsville Reservoir Leroy Reservoir Tar River Reservoir

I I I

screen/pump screen/pump screen/pump

I I I

Pre

- Disinfection Pre

- Disinfection Pre

- Disinfection

chlorine dioxide chlorine, PAC, aluminum salts and pre

- caustic

I potassium permanganate I

Flash Mixer I Flash Mixer

polymer coagulant Flocculation polymer

I aluminum salts/polymers I

Flocculati on/Sedimentation I Flocculation

lime Filtration I

I rapid sand and mixed media Sediment Basin

Flash Mixer I I

sodium silica fluoride Post

- Disinfection Dual Media Filtration

I chlorine, flouride, chlorine

Flocculation/Sedimentation ortho

- phosphate I

chlorine I Post

- Disinfection

I Clearwell Storage post

- caustic, fluoride, chlorine,

Dual Media Filtration I and phosphate

sand with GAC cap Storage I

I I Clearwell Storage

Post

- Disinfection Distribution I

chlorine Distribution

I

Clearwell Stora ge

I

DistributionSummary of Results from a Pilot Monitoring Program 11



### Table 4. Order of water

- treament stages and chemicals used during treatment for 12 community water

systems included in the pilot monitoring program

-- continued

Ohio Site Oklahoma Site Pennsylvania Site

Clermont Water Author ity Edmonds Water Supply Western Berks Water

Authority

Batavia, OH Arcadia, OK Reading, PA

East Fork (Harsha Lake) Lake Arcadia Blue Marsh Reservoir

I I |

screen/pump screen/pump reservoir release

I I |

Pre

- Disinfection Aeration Tulpehocken Cre ek

potassium permanganate, I I

chlorine dioxide Pre

- Disinfection screen/pump

I ozone I

Rapid Mix I Pre

- Disinfection

aluminum Flocculation / Clarification powdered activated carbon,

I polymers/lime potassium permanganate,

Flocculation I chlorine dio xide, and lime

pH adjustment, polymers Solids Contact / Clarification I

I carbon dioxide Flocculation / Clarification

Settling I aluminum sulfate

I Post

- Disinfection I

Filtration ozone Filtration

rapid sand with GAC I sand and anthracite

I Polyphos phate Polymer hydrofluosilicic acid

Post

- Disinfection chlorine I

phosphate, flouride, chlorine I Ammonium Sulfate

and caustic soda Mixed Media Filters chloramines

I multimedia I

Clearwell Storage I Corrosion control

I Carbon Filter phosphate

Distrib ution granular activated carbon I

I Clearwell Storage

Post

- Disinfection I

chlorine Reservoir

I I

Clearwell Storage Distribution

I

Distribution12 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 4. Order of water

- treament stages and chemicals used during treatment for 12 community water

systems included in the pilot monitoring program

-- continued

South Carolina Site South Dakota Site Texas Site

Spartanburg Waterworks Mitchell Water

Department City of Waxahachie Water

Treatment Plant

Chesnee, SC Mitchell, SD Waxahachie, TX

South Pacolet Reservoir Lake Mitchell Lake Bardwell

(Lake Bowen) I (seasonal, used to recharge

I screen/pump Lake Waxahachie)

Municipal Reservoir #1 I |

I GAC Polymers screen/pump

screen/pump I |

I lime, aluminum sulfate Lake Waxahachie

Pre

- Di sinfection polymers added I

liquid alum, lime, carbon, I screen/pump

chlorine, and polymer chlorine dioxide, I

I and fluoride added Pre

- Disinfection

Hydraulic Flocculation I potassium permanganate

aluminum salts, polymers ammonium poly phosphate ( seasonal, taste and odor)

I added free chlorine

Dual Media High Rate I I

Filters Post

- Disinfection Flocculation

I chlorine iron salts (ferric sulfate),

Post

- Disinfection I |

fluoride, lime, phosphate, Distribution Disinfection

and chlorine chloram ines

I |

Clearwell Storage Filtration

I dual media sand / anthracite

Distribution |

Corrosion Control

caustic soda (pH control)

hydrofluorisilic acid

|

Clearwell Storage

I

DistributionSummary of Results from a Pilot Monitoring Program 13



### Table 5. Process parameters of water from 12 co mmunity water systems participating in the pilot

monitoring program

[Mgal/D, million gallons per day; mg/L, milligrams per liter; PAC, powdered activated carbon; TOC, total organic carbon; n.a., not available]

Water quality properties

State System name Average

flow

through

time

(hours) Average

flow

- through

rate

(Mgal/d) pH

(standard

units) Alkalinity

(mg/L) Hardness

(mg/L) TOC

(mg/L) Seasonal

modifications to

treatment process

CA Elsinore Valley Municipal Water

District 3.25 5 7.5 91 250 6

- 8 None

IN Indianapolis Water Company 8.75 n.a. 8.2 128 200 4 PAC added as needed

following spring runoff

LA Tensas Water Distribution

Association, Inc. 1 n.a. 7.5 25.8 78.3 n.a. None

MO City of Higginsville Municipal

Utilities 26 1 7.9

- 9.2 63

- 120 90

- 145 4.7 treated with copper

sulfate, May through

September

NY Village of LeRoy Water

Department 0.29 0.75 7.8

- 9.0 40

- 100 ~140 4.4 Increase potassium

permanganate in

summer/fall for taste

and odor; PAC used as

backup

NC Tar River Water Treatment Pla nt 4

- 5 10 7 12 12 4

- 6 None

OH Clermont Water Authority 23 5 7.7 95 126 5.2 0.25 mg/L potassium

permanganate in winter

- 3.0 or greater by late

June

OK Edmonds Water Supply n.a. n.a. 7.9

- 8.8 137 150 5.8 Adjust ozone treatment

if taste and odor is

presen t

SC Spartanburg Waterworks 4 11 6.9 17 15 3.8 None

SD Mitchell Water Department 12

- 13 1.1

- 4.3 9.2 32 222 n.a. n.a.

PA Western Berks Water Authority 7

- 9 4 7.2 138 172 2

- 3 None

TX City of Waxahachie Water

Treatment Plant 10 6 7.7 100 108 4

- 8 P otassium

permanganate

(as needed for taste

and odor)

Process parameters including average flow

- through

time and average flow

- through rate are reported for each

of the 12 CWS plants in table 5. Water

- quality parameters

of raw water including normal ra nges of pH, alkalinity,

hardness, and total organic carbon are also included in

table 5 as they were reported by the CWSs. Several CWSs

reported seasonal modifications to the treatment process

that are used to address an increase in flow, increased

sedimen tation, or other changes in physical and chemical

characteristics of the source water. The average flow

- through time from collection of raw

water to the completion of the finished water ranged from

0.29 (NY) to 26 (MO) hours. Flow

- through time was

depende nt on the total amount of water treated and the

amount of time that the treated water remained in the

clearwells. Seasonal modifications are regularly made at

many of the sites investigated, and are mainly intended to

control the taste and odor of the wate r.14 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: Sampling Frequency

One objective of this study was to provide estimates of

annual

- mean pesticide concentrations and high

concentrations that occur for short periods of time, such as

the annual 95 th and 99 th percentile concentration. An

analysis of sam

pling

- frequency requirements by the

International Life Sciences Institute (ILSI, 1998)

recommended a fixed

- frequency sampling program of 100

times per year to develop measures of chronic (long

- term)

and acute (short

- term) exposure to pesticides in water

fr om streams. This level of effort was impractical for this

pilot program and was not necessary to meet the primary

goal of comparing raw

- and finished

- water concentrations.

However, the sampling frequency implemented was

designed to characterize the occurre nce of commonly

occurring pesticides and to identify compounds that may

occur for only a short period of time at concentrations

greater than the laboratory detection level.

The sampling frequency for this study was determined

on the basis of data from Per ry Lake, a large midwestern

reservoir in Kansas. During 1993

- 94, Perry Lake was

sampled on a daily basis and analyzed for triazine

herbicides using Enzyme

- Linked Immuno Assay kits

— a

low

- cost method for performing large numbers of

analyses

—with supplementa l samples sent to research

labs for confirmation. The Perry Lake data were provided

by Peter Van Meter (U.S. Geological Survey, written

commun., 1998) and were analyzed using quarterly,

monthly, bimonthly, 4

- times monthly, and 10

- times

monthly sampling fre quencies. In the analysis of Perry

Lake data, 10,000 replicates of each sampling frequency

were performed using a random starting date. Estimates of

the mean and standard deviation showed that quarterly

sampling was adequate to determine the annual

- mean

co ncentration of atrazine (table 6) (Charles Crawford, U.S.

Geological Survey, written commun., 1998). Estimates of

the maximum value and 95 th percentile showed that, based

on sufficiently small standard deviations, reasonable

measures of the actual values c ould be determined using a

monthly sampling frequency. Since this scenario is based

on a large reservoir system and a comparatively long

- lived

analyte, a semi

- weekly sampling frequency was selected

as the base level for this program.

A similar test scenar

io was performed on data from a

pesticide runoff / reservoir model. OPP modeled daily

atrazine and bromoxynil concentrations using the Pesticide

Root Zone Model

- Exposure Analysis Model System

(PRZM

- EXAMS) with the Shipman Reservoir scenario

(U.S. Environme ntal Protection Agency, 1998). The

watershed characteristics are representative of cotton

grown on a Loring silt loam in Mississippi using

conventional and no

- till management. Application rates

and timing were standardized to allow comparison

between pesti

cides with different environmental fate and transport characteristics, since bromoxynil is

significantly more reactive in the environment than

atrazine. Table 7 presents a summary of these scenarios

using 1976 precipitation data, showing the expected

p ercentiles and mean value, in addition to the mean and

standard deviation of 10,000 simulated sampling years for

one

- week and two

- week sampling intervals. The standard

deviation of the bromoxynil test is always a greater

percentage of the expected value th an for the atrazine

test

— indicating that more frequent sampling is necessary

for reactive compounds in order to achieve the same level

of precision. A 2

- week sampling interval sufficiently

characterized the 90 th percentile bromoxynil concentration

with a s tandard deviation of 20 percent of the peak model

value. In contrast, weekly sampling significantly

improved the estimate of the 90 th percentile concentration

with a standard deviation less than 5 percent of the peak

model value.Summary of Results from a Pilot Monitoring Program 15



### Table 6. Summary of atrazine

- con centration distributions based on 10,000 trials of selected fixed

frequency sampling strategies on daily concentration data from Perry Lake, Kansas, 1993

- 94

[Values, concentrations in micrograms per liter; n.d., not determined ]

Percentile

50 th 75 th 90 t h 95 th 99 th Maximum

Reported values, based on daily

samples 1.720 3.170 3.379 3.475 3.640 3.790

Quarterly sampling

Value 1.684 3.040 n.d. n.d. n.d. 3.437

Standard deviation 0.209 0.172 n.d. n.d. n.d. 0. 135

Monthly sampling

Value 1.691 3.102 3.408 3.536 n.d. 3.566

Standard deviation 0.105 0.149 0.064 0.094 n.d. 0.109

Bimonthly sampling

Value 1.703 3.138 3.390 3.501 n.d. 3.636

Standard deviati on 0.052 0.102 0.039 0.054 n.d. 0.090

4

- times monthly sampling

Value 1.712 3.171 3.385 3.493 n.d. 3.715

Standard deviation 0.026 0.018 0.021 0.030 n.d. 0.066

10

- times monthly sampling

Value 1.715 3.170 3 .382 3.480 3.665 3.775

Standard deviation 0.009 0.006 0.010 0.016 0.033 0.011



### Table 7. Summary statistics of 1

- week and 2

- week sampling

- interval test scenarios using PRZMS

EXAMS 1 

### model

- predicted atrazine and bromoxynil concentration for a small midwe stern

reservoir based on 1976 precipitation records and equivalent application rates

[Values, concentrations in micrograms per liter]

1

- Week sampling

interval 2

- Week sampling

interval Expected

Value

Mean Standard

deviation Mean Standard

deviation

At razine

Maximum value 4.710 4.586 0.091 4.387 0.204

99 th percentile 4.590 4.586 0.091 4.387 0.204

95 th percentile 4.040 4.060 0.066 4.043 0.072

90 th percentile 3.700 3.699 0.070 3.749 0.070

Mean 1.483 1.483 0.022 1.515 0.037

Bromoxynil

Maximum value 2.090 1.504 0.386 1.428 0.504

99 th percentile 1.460 1.504 0.386 1.428 0.504

95 th percentile 0.460 0.496 0.063 0.461 0.128

90 th percentile 0.134 0.122 0.031 0.125 0.027

Mean 0.066 0.066 0.015 0.083 0.026

1 U.S. Environmental Prote ction Agency, 199816 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Figure 3. Sample

- collection dates at the 12 pilot monitoring program sites in 1999 and 2000.

Based on both the Perry Lake concentration data and

PRZMS

- EXAMS model results, the design team chose to

implement three sampling frequencies (see ta ble 1):

-- Base sampling frequency

-- included quarterly

sampling, plus semi

- weekly sampling for a 4

- month period following pesticide application,

with samples collected from water intake,

finished

- water tap, and reservoir outflow (11

samples per year).

-- Hi g h

- frequency sampling

-- supplemented the

base sampling frequency with intake

- water

samples collected weekly over the 6

- month

period with highest pesticide applications (26

samples per year).

-- Enhanced sampling

- - supplemented the high

frequency sampling by col lecting samples from

the intake site every 3 days for about 1 month

after spring corn herbicide application (37

samples per year). Because pesticide concentrations are often serially

correlated and concentrations vary most during the

principal growing se ason, the weekly, semi

- weekly, and

enhanced sampling intervals were scheduled around the

principal application season, based on local knowledge

and analysis of historical data for these areas. Thus, the

measurements from the pilot program are representati ve of

compounds that are used and mobilized during the period

sampled and are less representative of concentrations

during the remainder of the year. The dates that samples

were collected from each monitoring site are shown in

figure 3. The actual samplin g frequency may differ

somewhat from the designed frequency because of site

specific scheduling and associated logistical concerns. The

enhanced sampling frequency was used at the IN site in

1999. These data are intended to support an analysis of

precision in sample statistics to further quantify the results

of the pilot monitoring program and other similar data

sets. In 2000, all sites were sampled at the base sampling

frequency and no samples were collected from reservoir

outflows.Summary of Results from a Pilot Monitoring Program 17 

## Methods of Sample Coll ection,

Analysis, and Quality Assurance

The field and data

- collection methods used in this

study followed or were adapted from standard USGS

protocols, and provided a high

- quality data set that is

consistent with the NAWQA Program and other USGS

trace

- orga nic water

- chemistry data

- collection efforts. The

sample

- collection, sample

- handling, and data

- management

protocols were outlined for all project participants in an

approved quality

- assurance project plan, which

documented the standard operating procedures to be

followed. The laboratory methods used in this study

encompass standard USGS methods, which have been

reviewed and approved by the USGS, and developmental

methods that are considered provisional for samples

analyzed during the study period.

Field Met hods

All water samples were collected by USGS personnel

using sample

- collection protocols documented by the

USGS and the NAWQA Program (Wilde and others,

1998). Consistent site

- visit and sample

- documentation

forms were completed at the time of sampling at each site.

During each site visit, water samples were collected from

the intake and finished

- water spigot and where necessary,

the spillway, for the analyses of dissolved pesticides.

Finished

- water samples were collected directly from a

spigot and filtered . Raw

- water samples were collected

from the intake or outflow site using either the equal

width

- increment or grab method. All samples were filtered

into a 1

- L glass amber bottle. Samples were processed

using methods described in Shelton (1994), however it

was not necessary to use a cone splitter to process

samples. Samples were shipped using overnight carriers in

sealed coolers to the USGS NWQL for analysis. No

preservatives or quenching agents, such as sodium

thiosulfate to remove residual chlorine, were a dded to the

water samples. In order to minimize the risk of cross

contamination, all sampling equipment was cleaned

according to standard protocols that include a thorough

cleaning with soapy tap water, followed by a distilled

water rinse, and a final rins e with laboratory

- grade

methanol. Quality

- assurance measures were conducted in

a manner consistent with the NAWQA stream

- sampling

quality

- assurance plan (Mueller and others, 1997). All

analytical data were computerized and returned to the

offices responsib le for sample collection, then compiled

into a single project data set. Analytical Methods

Three different laboratory methods were selected for

use during the pilot monitoring program

—a USGS

approved method and two developmental methods. The

primary me thod, known as method 2001 (or schedule

2001) uses C

- 18 solid

- phase extraction and gas

chromatography / mass spectrometry (GC/MS) to

determine concentrations of 47 pesticides and pesticide

degradates in water samples (Zaugg and others, 1995).

The two devel

opmental methods were included in this

program in order to greatly expand the available

information on the occurrence of a wide number of

pesticides and pesticide degradates in surface water across

the Nation, and to test for the occurrence of these

compou nds in drinking

- water supplies. These methods

were included with the knowledge that the methods were

developmental and that their performance may be more

variable than would be expected of methods that have

been thoroughly tested and approved. The two

deve lopmental methods were approved by the USGS in

2001

— without any changes to the proceedures.

Method 2001 was first developed in the early 1990s as

a means of isolating and quantifying a broad range of

target compounds while achieving low

- level method

report ing limits (ranging from .001 to .018 parts per

billion). The pesticides selected for inclusion in this

method were based on national use rates and their

chemical properties, which would permit isolation using

the C

- 18 cartridge and analysis by GC/MS. Thus , this

method encompasses many of the more widely used

pesticides, including many triazine and acetanilide

herbicides; selected carbamate compounds; and selected

organophosphate insecticides. Two pesticide metabolites,

deethylatrazine and 2,6 diethylanalin e, are also included in

this method. Method 2001 is the principal pesticide

analysis used throughout the Nation by the NAWQA

Program.

Standard performance of method 2001 for untreated

water samples has been documented based on quality

assurance samples col

lected by the NAWQA Program

from 1992

- 96 (Jeffrey Martin, 1999). That report provides

spiked

- sample recovery data for each analyte included in

method 2001, and indicates laboratory performance across

a range of time and sample matrices. Therefore, these

re sults are more indicative of the performance of the

method from monitoring data than performance estimates

provided in the method documentation. Each sample

analyzed during the pilot program was spiked with a

standard aliquot of a surrogate matrix prior to extraction,

which may be used to track the performance of the

analysis for individual samples. These results are reported

as a percent of the expected value. Surrogate

- spike

recoveries are included in the accompanying pilot

monitoring program data sets.18 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: Some pesticide

- concentration data from method 2001

are reported as qualified estimates. These samples have an

“E” in the parameter’s remark field. There are two cases

where concentrations are reported as qualified estimates.

The first case includes the per manently qualified

compounds deethylatrazine, azinphos

- methyl, carbaryl,

carbofuran, and terbacil. During method development,

deethylatrazine exhibited consistently low recoveries (9

- 19 percent) but was retained in the method due to its

national relevance. The other four compounds exhibited

variable recoveries and thus are reported as qualified

estimates. The second case includes qualitative detections

of concentrations less than the statistically determined

Method Reporting Level (MRL).

The first developme ntal method is provisional method

9002 (also known as schedule 9002), which is an

adaptation of the same C

- 18

- solid

- phase extraction and

GC/MS technology used in method 2001. The method

provides a quantitative analysis of 20 parent pesticides and

21 pestic ide degradates. Qualitative estimates are provided

for 14 parent pesticides and 20 degradates that through

testing, showed greater bias, higher variability, or shorter

holding times than the other compounds. The details of

this adaptation are described in Sandstrom and others

(2001) and should be used as a guide in the interpretation

of the results from this method. Selection of candidate

parent compounds for testing under this method was based

on national rankings of pesticide use, the existence of

current NWQL methods for these compounds, and the

chemical characteristics that make analysis by this method

favorable. Only compounds without an existing method

were tested. Inclusion of pesticide degradates was based

on whether the parent compound was included in a current

NWQL method and the availability of analytical

standards.

Method 9002 was implemented for conditional

analysis by the NAWQA Program in March 1999, when

the pilot monitoring program started. The method was

approved for routine analysis in 2001 and is now referred

to as method 2002. Although the method is now approved,

the data collected during this program must be considered

provisional, as the analyses were performed prior to

method approval. Thus, these data will not be included as

part of the USGS’s publicly accessible National Water

Information System (NWIS). These data are available to

the public; however, they must be accompanied by the

documentation of analytical methodology in accordance

with USGS policy (U.S. Geological Survey Office of

Water Quality Technical Memorandum No. 98.05, 1998).

During the period of study, no changes were made to the

method or instrument settings. Therefore, the data from

method 9002 should be consistent throughout the study,

with the possible exception of the f irst 2 months, when the

instruments were brought on line (Mark Sandstrom, U.S.

Geological Survey, oral commun., 1999). The second developmental method, provisional

method 9060, is a substantially new technique using solid

phase extraction and high

- performa nce liquid

chromatography/mass spectrometry (HPLC/MS) for the

instrumental analysis of extracts. This method is designed

to determine low

- level concentrations of 64 polar

pesticides and pesticide degradates. The use of HPLC/MS

for this method provides impr oved sensitivity and

selectivity over a previous method that included many of

the same compounds, particularly in the presence of

dissolved organic matter. Complete documentation of

method 9060, now known as method 2060, can be found

in Furlong and others (2001).

Samples analyzed using method 9060 pose the same

set of qualifications as described for method 9002. The

data are to be considered provisional, and interpreted with

the knowledge that variability in concentration detections

and quantifications may be greater than expected in a

production method. An additional qualification should be

given to samples analyzed during 1999, the first year of

study. During this period, while the method was still in the

testing phase, the NWQL received an unusually large

number of requests for this method

— an amount greater

than their instrumental capacity. As a result, a significant

backlog developed and many samples were stored in

refrigerators before extraction well beyond recommended

holding times, with some as long as 180 days. NWQL has

additional holding

- time studies underway that may

identify the compounds most vulnerable to degradation.

Sample

- holding times are available for each of the

samples collected during the pilot monitoring program. By

December 1999, NWQL ha d resolved the backlog by

adding additional instruments and analysts. The likely

implications of extended holding times for the pilot

monitoring program’s provisional method 9060 are as

follows

— first, it is likely that in 1999, some compounds

in some sampl

es may have degraded to less than the MRL

prior to extraction and analysis. Second, it is likely that

reported concentrations are lower than would have been

determined through extraction and analysis within

prescribed holding times. And finally, it is poss ible that

transformations may have occurred that produced a

detectable degradate or elevated the concentration of a

degradation compound relative to the concentration at the

time of sampling. Ongoing NWQL holding

- time studies

may indicate which compounds a re more susceptible to

degradation and transformation.Summary of Results from a Pilot Monitoring Program 19 

## Summary of Results from the Pilot

Monitoring Program

Summary tables are presented for each of the

laboratory methods performed during the pilot monitoring

program. These tables provide a systematic vi ew of the

analytical results for samples from raw

- water

- supply

intake and finished

- water sampling locations and are

ordered by detection frequency to aid the reader in

identifying the most commonly detected compounds.

Summary tables were not prepared for t he reservoir

outflow sites because much of the information was

redundant between raw

- water samples at the intake and

reservoir

- outflow samples. In addition, not all sampling

sites included a reservoir

- outflow sampling point. A

summary of analytical results for individual sampling sites

is presented as supplemental information at the end of this

report.

Each summary table presents the MRL for all

compounds analyzed, summarizes the detection frequency,

and presents the upper bounds of detected concentration s

as the maximum value and 95 th percentile concentrations.

Those compounds that were included in the analysis but

were not detected in any sample are listed with their MRL

following the table. The summary statistics presented in

tables 8, 9, and 10 are an aggregation of all data collected

in this study, so that although the percent detection

frequencies, 95 th percentile values and maximum

concentrations reflect the data as a whole, they do not

represent conditions at any one site. The summary

statistics are also influenced more by samples from the

frequently sampled sites than the other sites. No measure

of central tendency, such as mean or median value, is

presented for the entire data set because only 11

compounds had detection frequencies greater than 50

percent. Median concentrations are presented for

individual sites where detection frequencies exceeded 50

percent in the supplemental tables. The supplemental

tables also present the higher

- level concentrations as 90 th

percentiles because many sites had an insufficient number

of samples to calculate the 95 th percentile.

In 1999, drought conditions extended across the

Eastern Unites States and California, thus the conditions

measured at six sites in 1999 (CA, OH, NC, NY, PA, and

SC) were not representative of average runoff patterns.

Drought conditions ended in the Eastern States in

September 1999, when Hurricane Floyd produced flood

conditions at most of the eastern sites. LeRoy Reservoir in

NY had pesticide concentration

- data collected in 1998

from another program (Phillips and others, 1999). In 1998

the maximum observed concentration of metolachlor was

greater than 2.0 μ g/L (micrograms per liter); and in 1999,

the maximum concentration was 0.17 μ g/L. This indicates

that concentrations and detection frequencies from 1999 may have been strongly affected by the drought, and was a

primary consideration in the decision to ext end sampling

through 2000.20 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: Gas Chromatography / Mass Spectrometry (method

2001)

The results of analysis using method 2001 show that

widely used herbicides are frequently detected in raw

water samples from water

- supply intakes. Atrazine,

metolachlor, and simazine were detected at every raw

water intake site; and deethylatrazine, a triazine degradate,

was detected in raw

- water samples from all sites except

CA. Each of these compounds was detected in more than

90 percent of the 323 raw

- water samples. Other commonly

used herbicides including prometon, cyanazine,

tebuthiuron, acetochlor, and alachlor were detected in

greater than 26 percent of all intake samples. Insecticides

were detected less frequently in intake samples than

herbicides. Diazinon (35.3 perce nt) and chlorpyrifos (5.3

percent) were the two most frequently detected

insecticides, with p,p’

- DDE, azinphos

- methyl, carbaryl,

carbofuran, and dieldrin occurring in fewer than 5 percent

of all raw

- water samples. In all, 17 compounds were

detected in less than 5 percent of the intake samples. In

most cases, the occurrence of these compounds is limited

to only a few sites. The observed detection frequencies for

intake

- water samples are similar to those reported for 58

stream sites sampled by the NAWQA progr am during

1992

- 95 (Larson and others, 1998).

Herbicides were frequently detected in finished

- water

samples and the high

- use compounds were found in

frequencies only slightly lower than those of raw water.

Metribuzin, however, was detected in nearly 15 pe rcent of

the intake samples and was not detected in any finished

water sample. None of the herbicides were detected in

finished water at a concentration greater than a national

drinking

- water criterion.

Six insecticides (

p,p’

- DDE, azinphos

- methyl, carbary l,

carbofuran, fonofos, and phorate) were detected in

finished

- water samples, with each of these compounds

detected in less than 3 percent of the samples. Fonofos

was detected in three finished

- water samples and phorate

in one sample

— neither of these comp ounds was detected

in raw water. Three of the organophosphorus insecticides

found in raw

- water samples (diazinon, chlorpyrifos, and

malathion) were not detected in any finished

- water

samples. Several studies have shown that

organophosphorus compounds are r eadily oxidized in the

presence of chlorine (Adnan and Yurdun, 1999; Aizawa

and others, 1994). The oxidative products of these

compounds include diazoxon, chlorpyrifos

- oxygen analog,

and malaoxon.Summary of Results from a Pilot Monitoring Program 21



### Table 8. Summary of analysis of pesticides in water samples from w ater

- supply intakes and finished

water

- supply taps using gas chromatography / mass spectrometry

— U.S. Geological Survey

National Water Quality Laboratory method 2001

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than th e method reporting level; ()=qualified estimates of pesticide

concentrations

-- for concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method

performance; H, herbicide; D, degradate; I, insecticide]

Samples from raw

- water intake (n = 323) Samples from finished

- water tap (n = 228)

Compound (class) Method Number Detection 95 th Maximum Number Detection 95 th Maximum

reporting of frequency percentile value of frequency percentile value

l evel detections in percent value detections in percent value

Atrazine (H) 0.001 311(8) 96.3 0.516 11.600 218(13) 95.6 1.400 2.470

Simazine (H) 0.005 293(6) 90.7 0.028 1.520 192(7) 84.2 0.385 0.571

Deethylatrazine (D) 0.002 289(289) 89.5 0.080 0.771 203(2 03) 89.0 0.265 0.352

Metolachlor (H) 0.002 288(12) 89.2 0.033 3.320 198(4) 86.8 0.336 0.661

Prometon (H) 0.018 241(164) 74.6 0.017 0.138 145(109) 63.6 0.067 0.103

Cyanazine (H) 0.004 145(4) 44.9 0.007 0.332 96(3) 42.1 0.128 0.355

Tebuthiuron (H) 0.010 135 (87) 41.8 0.010 0.030 64(46) 28.1 0.019 0.032

Acetochlor (H) 0.002 115 35.6 0.002 0.334 69(1) 30.3 0.061 0.395

Diazinon (I) 0.002 114(20) 35.3 0.002 0.101 0 0.0

--- --- Alachlor (H) 0.002 87(5) 26.9 0.002 0.655 51(4) 22.4 0.027 0.148

Metribuzin (H) 0.004 47 14.6 0.004 0.291 0 0.0

--- --- Pronamide (H) 0.003 34 10.5 0.003 0.048 9(1) 3.9

--- 0.017

EPTC (H) 0.002 25(5) 7.7 0.002 0.037 12(1) 5.3 0.005 0.030

Chlorpyrifos (I) 0.004 17(9) 5.3 0.004 0.034 0 0.0

--- --- Dacthal (H) 0.002 16(15) 5.0 0.002 0.014 8(8) 3.5

--- 0.004

p,p'

- DDE (I) 0.006 14(14) 4.3

--- 0.006 6(6) 2.6

--- 0.006

Trifluralin (H) 0.002 9(9) 2.8

--- 0.009 5(4) 2.2

--- 0.009

Azinphos

- methyl (I) 0.001 8(8) 2.5

--- 0.144 5(5) 2.2

--- 0.114

Terbacil (H) 0.007 7(7) 2.2

--- 0.100 0 0.0

--- --- Car baryl (I) 0.003 7(7) 2.2

--- 0.047 2(2) 0.9

--- 0.041

Malathion (H) 0.005 6 1.9

--- 0.106 0 0.0

--- --- Pendimethalin (H) 0.004 6 1.9

--- 0.125 3 1.3

--- 0.010

Fonofos (I) 0.003 0 0.0

--- --- 3 1.3

--- 0.040

Carbofuran (I) 0.003 2(2) 0.6

--- 0.050 3(3) 1.3

--- 0.030

2,6 Diethylaniline (D) 0.003 2(2) 0.6

--- 0.003 1(1) 0.4

--- 0.003

Phorate (I) 0.002 0 0.0

--- --- 1(1) 0.4

--- 0.011

Benfluralin (H) 0.002 1(1) 0.3

--- 0.010 0 0.0

--- --- Butylate (H) 0.002 1(1) 0.3

--- 0.002 0 0.0

--- --- Dieldrin (I) 0.0 01 1(1) 0.3

--- 0.010 0 0.0

--- --- Linuron (H) 0.002 1 0.3

--- 0.035 0 0.0

--- ---

Molinate (H) 0.004 1(1) 0.3

--- 0.004 0 0.0

--- --- Napropamide (H) 0.003 1(1) 0.3

--- 0.007 0 0.0

--- ---

Parathion

- methyl (I) 0.006 1 0.3

--- 0.061 0 0.0

--- ---

Triall ate (H) 0.001 1(1) 0.3

--- 0.002 0 0.0

--- ---

The following compounds were not detected in any water sample. Method detection level in micrograms per liter shown in ()’s. Herbicide : Ethalfluralin (0.004), Pebulate (0.004), Propachlor (0.007), Propanil (0 .004), Thiobencarb (0.002), Insecticide : alpha

- HCH (0.002),

Disulfoton (0.017), Ethoprop (0.003), Lindane (0.004), Parathion (0.004), Permethrin, cis (0.005), Propargite (0.013), Terbufos (0.013),22 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: Gas Chromatography / Mass Spectrometry (provisional

method 9002)

Compounds included in NWQL provisional method

9002 were generally detected much less frequently than

compounds in method 2001. Two compounds were

detected in more than 10 percent of the intake samples

— 3,4

- dichloroaniline with 19.9 percent detection s, and

prometryn with 16.1 percent detections (table 9). 3,4

- dichloroaniline was detected in only one finished

- water

sample and prometryn was not detected in any finished

water samples. 3,4

- Dichloroaniline is a degradation

product of three different compo unds: linuron, propanil,

and neburon. Sandstrom and others (2001) reported that

diruon may be transformed to 3,4

- dichloroaniline in the

gas chromatograph injection port and that some

percentage of the reported concentration of this compound

may originate f rom diuron in the sample extract.

Twenty

- one degradation products were found in water

samples using this method

— 17 in raw water and 14 in

finished

- water samples. Malaoxon, the principal oxidative

transformation product of malathion, was detected in 11

fini shed

- water samples and none of the raw

- water

samples. In three of the samples where malaoxon was

detected in finished water, the corresponding intake

sample showed measurable concentrations of malathion.

Other transformation products that were detected in more

finished

- water samples than intake samples include:

azinphos

- methyl

- oxon, fenamiphos sulfone, terbufos

- O

analogue sulfone, and 4

- chloro

- 2

- methyl phenol (a

degradate of MCPA and MCPB). Chlorpyrifos oxygen

analog was not detected in any finished

- water s amples,

although chlorpyrifos was detected in 5.3 percent of the

raw

- water samples using method 2001.

Most compounds detected with this method were

found in four or fewer of the intake or finished

- water

samples, with most concentrations observed at or near the

method detection level. Of these, 23 were detected in raw

water samples and 16 were detected in finished

- water

samples. Forty

- one of the 75 compounds reported were

not detectable in any intake or finished

- water sample.Summary of Results from a Pilot Monitoring Program 23



### Table 9. Summary of analysis of modera te

- use pesticides and degradates in water samples from water

supply intakes and finished water

- supply taps using gas chromatography / mass spectrometry

— U.S. Geological Survey National Water Quality Laboratory provisional method 9002

[Concentrations shown i n micrograms per liter;

--- indicates value reported as less than the method reporting level; ()=qualified estimates of pesticide

concentrations

-- for concentrations quantified less than the method reporting level and for compounds with low and variable re coveries based on method

performance; H, herbicide; D, degradate; I, insecticide; F, fungicide]

Samples from raw

- water intake (n = 317) Samples from finished

- water tap (n = 221)

Compound (Class) Method Number Detection 95 th Maximum Number Detection 95 th Maximum

reporting of frequency percentile value of frequency percentile value

level detections in percent value detections in percent value

3,4

- Dichloroaniline (D) 0.008 63(21) 19.9 0.019 0.061 1(1) 0.5

--- 0.008

Prometryn (H) 0.005 51(23) 16.1 0.026 0.041 0 0.0

--- --- Malaoxon (D) 0.016 0 0.0

--- --- 11(3) 5.0 0.016 0.556

3

- Trifluoromethylaniline (D) 0.005 12(11) 3.8

--- 0.008 0 0.0

--- --- 2

- [2

- Ethyl

- 6

- methylphenyl)

amino]

- 1

- propanal (D) 0.016 11(9) 3.5

--- 0.074 6(6) 2.7

--- 0.016

2,5

- Dichloroanili

ne (D) 0.005 10(2) 3.2

--- 0.020 2(1) 0.9

--- 0.009

Azinphos

- methyl

- oxon (D) 0.031 1 0.3

--- 0.263 4(4) 1.8

--- 0.063

4

- Chloro

- 2

- methyl

phenol (D) 0.005 1(1) 0.3

--- 0.005 4(4) 1.8

--- 0.007

2

- Chloro

- 2,6

- diethylacet

anilide (D) 0.008 4 1.3

--- 0.012 0 0.0

--- --- Dimethoate (I) 0.005 4(1) 1.3

--- 0.022 0 0.0

--- ---

Metalaxyl (F) 0.016 4(4) 1.3

--- 0.016 2(2) 0.9

--- 0.016

4

- (Hydroxymethyl)

pendimethalin (D) 0.031 3(3) 0.9

--- 0.045 1(1) 0.5

--- 0.126

1,4

- Naphthoquinone (D) 0.008 3(3) 0.9

--- 0.008 1(1) 0 .5

--- 0.008

1

- Naphthol (D) 0.005 3(3) 0.9

--- 0.228 0 0.0

--- --- Endosulfan sulfate (D) 0.008 3(2) 0.9

--- 0.009 2(2) 0.9

--- 0.008

Myclobutanil (F) 0.008 3(2) 0.9

--- 0.015 0 0.0

--- --- Tebupirimphos (I) 0.008 3(3) 0.9

--- 0.008 0 0.0

--- --- 4,4'

- Dic hlorobenzo

phenone (D) 0.008 0 0.0

--- --- 2(2) 0.9

--- 0.008

Fenamiphos sulfone (D) 0.008 1(1) 0.3

--- 0.008 2(1) 0.9

--- 0.016

Terbufos

- O

- analogue

sulfone (D) 0.016 0 0.0

--- --- 2(2) 0.9

--- 0.016

Fenamiphos sulfoxide (D) 0.031 2(1) 0.6

--- 0.033 1(1 ) 0.5

--- 0.031

Hexazinone (H) 0.008 2(2) 0.6

--- 0.008 0 0.0

--- ---

Tefluthrin metabolite

[R 119364] (D) 0.005 2(2) 0.6

--- 0.005 0 0.0

--- --- Tefluthrin metabolite

[R 152912] (D) 0.008 2(1) 0.6

--- 0.021 0 0.0

--- --- 3,5

- Dichloroaniline (D) 0.005 0 0.0

--- --- 1 0.5

--- 0.009

Bifenthrin (I) 0.005 0 0.0

--- --- 1(1) 0.5

--- 0.005

Iprodione (F) 0.031 0 0.0

--- --- 1(1) 0.5

--- 0.031

Isofenphos (I) 0.008 1(1) 0.3

--- 0.008 1(1) 0.5

--- 0.008

cis

- Propiconazol (F) 0.005 1(1) 0.3

--- 0.005 0 0.0

--- --- Di sulfoton sulfone (D) 0.005 1 0.3

--- 0.013 0 0.0

--- ---

Disulfoton sulfoxide (D) 0.016 1(1) 0.3

--- 0.016 0 0.0

--- --- Methidathion (I) 0.008 1 0.3

--- 0.110 0 0.0

--- --- Tefluthrin (I) 0.008 1(1) 0.3

--- 0.008 0 0.0

--- ---

trans

- Propiconazol (F) 0.00 5 1(1) 0.3

--- 0.005 0 0.0

--- ---

The following compounds were not detected in any water sample. Method detection level in micrograms per liter shown in ()’s.

Defoliant : Tribuphos (0.016); Fungicide : E

- Dimethomorph (0.031), Z

- Dimethomorph (0.031), Ethio n monoxon (0.008); Herbicide : Cycloate (0.016),

Oxyfluorfen (0.016), Terbuthylazine (0.005); Insecticide : Cyhalothrin (0.008), Cyfluthrin (0.031), Cypermethrin (0.031), Dicrotophos (0.016), Ethion

(0.005), Fenthion (0.005), Phosmet (0.008), Profenofos (0.0 08), Propetamphos (0.016), Sulfotepp (0.005), Sulprofos (0.005), Temephos (0.031); Nematocide :

Fenamiphos (0.016); Plant Growth Regulator : Flumetralin (0.016);

Degradate : 2

- Amino

- N

- isopropylbenzamide (0.005), 2

- Ethyl

- 6

- methylaniline (0.005), 3

- Phenoxybenzy l alcohol (0.031), 4

- Chlorobenzylmethyl sulfone

(0.008), Chlorpyrifos oxygen analog (0.016), c

- Methyl

- 3

- (2,2

- dichlorovinyl)

- 2,2

- dimethyl

- (1

- cyclopropane)

- carboxylate (0.016), 2

- (4

- tert

- butylphenoxy)

cyclohexanol (0.016), Diclorvos (0.005), alpha

- Endosulfa n (0.016), beta

-

Endosulfan (0.016), Endosulfan

- ether (0.016), Fenthion sulfoxide (0.008), Fonofos

oxygen analog (0.016), O

- ethyl

- O

- methyl

- S

- propylphosphorothioate (0.005), t

- Methyl

- 3

- (2,2

- dichlorovinyl)

- 2,2

- dimethyl

- (1

- cyclopropane)

- carboxylate

(0.016), Pa

raoxon

- ethyl (0.031), Paraoxon

- methyl (0.031), Phorate oxon (0.031), Phosmet oxon (0.016), Tebupirimphos oxygen analog (0.016)24 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: High

- Performance Liquid Chromatography / Mass

Spectrometry (provisional method 9060)

Sample results for NWQL provisional metho d 9060

(table 10) also show that the widely used herbicides are

often detected in samples of both raw and finished water.

This method provides data on three additional triazine

degradation products that are not included in method

2001, including: 2

- hydroxy atrazine, deisopropylatrazine,

and desethyl

- desisopropylatrazine. Each of these

compounds was detected in greater than 60 percent of the

raw

- and finished

- water samples and the maximum

observed concentrations were nearly equal between the

two sample sourc es. Atrazine and deethylatrazine are

included in method 9060 and method 2001, however, the

MRL for these compounds, as well as other compounds, in

method 9060 are generally much greater than for

compounds included in method 2001, and range from 0.01

to 0. 1 14 μ g/L. Therefore, the detection frequencies based

on this method are expected to be somewhat lower for

compounds that are included in both methods.

Nine herbicides and one fungicide (metalaxyl) were

detected in greater than 10 percent of the raw

- water

s amples. Four of these compounds (diuron, bentazon,

chlorimuron

- ethyl, and sulfometuron

- methyl) were

detected in less than 10 percent of the finished

- water

samples. A total of 48 pesticide compounds were detected

in intake or finished

- water samples. An add itional 16

compounds were included in the method but not detected

in any water samples.

Caffeine is not a widely used pesticide or a

degradation product, but it was included in this method

because of its utility as an indicator of wastewater effluent

and b ecause its chemical characteristics make it well

suited for this analytical technique. Caffeine was detected

in about 36 percent of all intake samples.Summary of Results from a Pilot Monitoring Program 25



### Table 10. Summary of analysis of pesticides in water samples from water

- supply intakes and finished

water

- supply taps using high performance liquid chromatography / mass spectrometry

— U.S.

Geological Survey National Water Quality Laboratory provisional method 9060

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method repor ting level; ()=qualified estimates of pesticide

concentrations

-- for concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method

performance; H, herbicide; D, Degradate; I, insecticide; F, fungicide]

Samples from raw

- water intake (n = 312) Samples from finished

- water tap (n = 225)

Compound Method Number Detection 95 th Maximum Number Detection 95 th Maximum

reporting of frequency percentile value of frequency percentile value

Level de tections in percent value detections in percent value

Atrazine (H) 0.074 265(140) 84.9 1.888 6.176 185(86) 82.2 1.118 1.944

2

- Hydroxyatrazine (D) 0.193 256(255) 82.3 1.263 2.058 182(182) 81.3 1.008 1.785

Deisopropylatrazine (D) 0.074 250(210) 80.1 0.195 0.386 146(136) 64.9 0.081 0.178

Deethylatrazine (D) 0.087 249(196) 79.8 0.340 0.546 167(147) 74.6 0.201 0.267

Desethyl desisopropyl

atrazine (D) 0.060 216(184) 69.2 0.079 0.150 141(137) 62.7 0.060 0.150

2,4

- D (H) 0.077 179(92) 57.4 0.158 0.414 98(60) 43 .6 0.132 0.634

Metalaxyl (F) 0.057 133(123) 42.6 0.057 0.351 80(79) 35.6 0.057 0.072

Tebuthiuron (H) 0.077 118(118) 37.8 0.077 0.077 42(42) 18.7 0.077 0.077

Diuron (H) 0.079 117(70) 37.5 0.319 0.540 13(13) 5.8 0.079 0.079

Caffeine* 0.081 112(88) 35.9 0.108 88.000 24(24) 10.7 0.081 0.081

Bentazon (H) 0.019 80(80) 25.6 0.021 0.344 21(21) 9.3 0.019 0.019

2,4

- D methyl ester (D) 0.087 77(77) 24.7 0.087 0.087 44(42) 19.6 0.087 0.136

Dicamba (H) 0.096 61(45) 19.6 0.100 0.192 35(31) 15.6 0.096 0.147

Chlorimuron

- et hyl (H) 0.037 52(45) 16.7 0.037 0.058 4(4) 1.8

--- 0.040

Bromacil (H) 0.081 49(47) 15.7 0.081 0.481 2(2) 0.9

--- 0.481

Sulfometuron

- methyl (H) 0.039 38(21) 12.2 0.095 0.160 6(6) 2.7

--- 0.039

Fluometuron (H) 0.062 24(5) 7.7 0.145 0.264 19(17) 8.4 0.062 0. 100

Clopyralid (H) 0.041 21(8) 6.7 0.042 0.170 4(3) 1.8

--- 0.059

Benomyl (F) 0.022 20(19) 6.5 0.022 0.038 2(2) 0.9

--- 0.215

Picloram (H) 0.071 11(1) 3.5

--- 1.441 11(1) 4.9 0.094 0.389

Imazaquin (H) 0.103 14(14) 4.5

--- 0.351 9(9) 4.0

--- 0.111

Nicosulf uron (H) 0.065 9(9) 2.9

--- 0.139 8(8) 3.6

--- 0.093

Imazethapyr (H) 0.088 10(10) 3.4

--- 0.133 3(3) 1.4

--- 0.088

Flumetsulam (H) 0.087 9(9) 2.9

--- 0.088 4(4) 1.8

--- 0.087

MCPA (H) 0.059 9(7) 2.9

--- 0.121 1 0.4

--- 0.077

Diphenamid (H) 0.058 7(7) 2.2

--- 0.058 3(3) 1.3

--- 0.058

Norflurazon (H) 0.077 6(5) 1.9

--- 0.414 0 0.0

--- --- Bromoxynil (H) 0.057 0 0.0

--- --- 4(4) 1.8

--- 0.057

Oryzalin (H) 0.071 3 1.0

--- 0.127 4(2) 1.8

--- 0.095

Triclopyr (H) 0.101 3(3) 1.0

--- 0.101 4(4) 1.8

--- 0.101

Acifl uorfen (H) 0.062 5(5) 1.7

--- 0.062 1(1) 0.5

--- 0.062

3(4

- chlorophenyl)

- 1

- methyl

urea (D) 0.092 5(5) 1.6

--- 0.092 0 0.0

--- ---

Metsulfuron

- methyl (H) 0.114 4(3) 1.3

--- 1.194 1(1) 0.4

--- 0.200

Dichlorprop (H) 0.050 3(3) 1.0

--- 0.050 1(1) 0.4

--- 0.05 0

Oxamyl oxime (D) 0.064 0 0.0

--- --- 2(2) 0.9

--- 0.064

2,4

- DB (H) 0.054 0 0.0

--- --- 2(2) 0.9

--- 0.054

Carbaryl (I) 0.063 2(2) 0.6

--- 0.063 0 0.0

--- --- Carbofuran (I) 0.057 2(2) 0.6

--- 0.057 1(1) 0.4

--- 0.057

Dinoseb (H) 0.043 2(2) 0.6

--- 0.04 3 1(1) 0.4

--- 0.043

Siduron (H 0.093 2(2) 0.6

--- 0.093 0 0.0

--- --- 

### * Caffeine is not a pesticide compound, however it is included in this method.26 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 10 Summary of analysis of pesticides in water samples from water

- supply intakes and finished

water

- supply taps using high performance liquid chromatography / mass spectrometry

— U.S.

Geological Survey National Water Quality Laboratory provisional method 9060

– Continued.

Samples from raw

- water intake (n = 312) Samples from finished

- water tap (n = 225)

Co mpound Method Number Detection 95 th Maximum Number Detection 95 th Maximum

reporting of frequency percentile value of frequency percentile value

level detections in percent value detections in percent value

Propoxur (I) 0.059 1(1) 0.3

--- 0.059 1 0.5

--- 0.823

3

- Hydroxycarbofuran (D) 0.062 0 0.0

--- 0.062 1(1) 0.4

--- 0.062

Bendiocarb (I) 0.061 0 0.0

--- 0.061 1(1) 0.4

--- 0.061

Neburon (H) 0.075 1(1) 0.3

--- 0.075 1(1) 0.4

--- 0.075

Propiconazole (F) 0.064 1(1) 0.3

--- 0.064 1(1) 0.4

--- 0.064

Chlora mben methyl ester (H) 0.114 1 0.3

--- 0.126 0 0.0

--- --- Aldicarb sulfone (D) 0.160 1(1) 0.3

--- 0.160 0 0.0

--- --- Imidacloprid (I) 0.106 1(1) 0.3

--- 0.106 0 0.0

--- --- Terbacil (H) 0.095 1(1) 0.3

--- 0.100 0 0.0

--- ---

The following compounds were not detected in any water sample. Method detection level in micrograms per liter shown in ()’s:

Herbicide : Chlorothalonil (0.049), Cycloate (0.054), Fenuron (0.074), Linuron (0.070), MCPB (0.063), Propham (0.072), Tribenuron

methyl (0.068), Insecticide : Aldicarb (0.082), Methiocarb (0.080), Methomyl (0.077), Oxamyl (0.016), Degradate : 3

- keto

- carbofuran

(0.072), Aldicarb sulfoxide (0.027), Bensulfuron

- methyl (0.048), Dacthal monoacid (0.072), Methomyl oxime (0.010),



## Summary

The pilot monitoring prog ram described in this report

was initiated by the U.S. Geological Survey National

Water

- Quality Assessment Program and the U.S.

Environmental Protection Agency Office of Pesticide

Programs to provide monitoring data on pesticide

concentrations in drinking water because the Office of

Pesticide Programs has responsibility under the Food

Quality Protection Act of 1996 to assess aggregate risk

from exposure to pesticides in drinking water based on

available data. This program was designed to fill

important dat a gaps and to provide more information

about appropriate methods for National monitoring of

pesticides in drinking water. This report presents and

summarizes the data collected during the pilot monitoring

program conducted in 1999 and 2000. The design of t he

monitoring program is described in order to facilitate

effective analysis of the data collected to meet a broad

array of goals and objectives.

The pilot monitoring program was designed as a first

step towards a long

- term goal of characterizing human

ex posure to pesticide residues in drinking water derived

from surface

- water sources. The principal goal of this

program is to develop a data set on the occurrence of

pesticides in drinking

- water sources that is tied to

pesticide concentrations observed in fi nished drinking

water. Reservoirs and community water systems that

withdraw from reservoirs were selected for this pilot

monitoring program because reservoirs are considered to be highly vulnerable to pesticide contamination, serve as

integrators of pestic ide loading from their watersheds, and

are important sources of drinking water.

Twelve community water systems supplied by

reservoirs were selected for study based on their

vulnerability to pesticides from their contributing

watersheds. The reservoirs sam pled range in size from 120

to 92,600 acre

- feet normal capacity, with contributing

watersheds ranging from 3.3 to 784 square miles and are

located in California, Indiana, Ohio, Oklahoma, Louisiana,

Missouri, South Carolina, South Dakota, New York, North

Ca rolina, Pennsylvania, and Texas. Ten of these sites were

selected because they were representative of regional

agricultural practices and two sites (Oklahoma and

California) were selected because they were representative

of urban pesticide runoff.

The pri mary sampling approach involved sample

collection from the raw

- water intake as well as from the

finished

- water tap located at the entry point to the

distribution system. Samples were also collected at the

outflow of many of the reservoirs because the water

quality conditions at an intake may substantially differ

from average reservoir conditions. All samples were

collected by trained U.S. Geological Survey personnel,

following sample

- collection protocols documented by the

U.S. Geological Survey. The samplin g frequency was

designed to characterize the occurrence of commonly

occurring pesticides and to identify compounds that may

occur for only a short period of time at concentrations

greater than the laboratory reporting level. Each site was

sampled quarterly over a one

- year period, with semi

-Summary of Results from a Pilot Monitoring Program 27

weekly samples collected during a 4

- month period

coincident with the most intensive application season.

Four site had additional raw

- water samples collected every

week for a 6

- month period. In 1999, drought conditions

ext ended across the Eastern Unites States and California,

thus the conditions measured at six sites in 1999 were not

representative of average runoff patterns. This was a

primary consideration in the decision to extend sampling

at nine sites through 2000.

Thr ee laboratory methods were used during the pilot

monitoring program

—an approved method and two

developmental methods. Together, these three methods

measure 178 different pesticides and pesticide degradation

products in filtered

- water samples. The primary method,

method 2001, uses C

- 18 solid

- phase extraction and gas

chromatography / mass spectrometry to determine

concentrations of 47 pesticides and pesticide metabolites

in water samples. The two developmental methods were

included in this program in order t o expand the available

information on the occurrence of a wide number of

pesticides and pesticide degradates in surface water across

the Nation, and to test for the occurrence of these

compounds in drinking

- water supplies. These methods

were included with the knowledge that the methods were

developmental and that the performance of the methods

may be more variable than would be expected of a

thoroughly tested and approved method. Provisional

method 9002 is an adaptation of the C

- 18 solid

- phase

extraction an d gas chromatography / mass spectrometry

technology used in method 2001. The method provides a

quantitative analysis of 20 parent pesticides and 21

pesticide degradates, and provides qualitative estimates for

14 parent pesticides and 20 degradates. Provisi onal

method 9060 is a substantially new technique using

graphitized carbon solid

- phase extraction and high

performance liquid chromatography/mass spectrometry for

the instrumental analysis of extracts. This method is

designed to determine low

- level concent rations of 64 polar

pesticides and pesticide degradates.

Overall, the three methods provided analyses for 178

different parent pesticide or degradation products. Of

these, 108 compounds were detected in at least one sample

of raw water at an intake or of finished water. Many of

these compounds, however, were detected in fewer than 5

percent of the samples and at concentrations very near the

method reporting level. The observed detection

frequencies for intake water are similar to those reported

for 58 stre am sites sampled by the NAWQA program in

1992

- 95.

The results show that widely used herbicides and

triazine degradation products are frequently detected in

samples from water

- supply intakes as well as in finished

water samples. Atrazine, simazine, and me tolachlor were

detected in at least one raw

- water sample from each of the

12 monitoring sites; and deethylatrazine, a triazine

degradate, was detected in raw

- water samples from all sites except the California site. Other commonly used

herbicides including metolachlor, prometon, cyanazine,

2,4

- D, tebuthiuron, acetochlor and alachlor were detected

in more than 26 percent of all intake samples. Insecticides

were detected less frequently in intake samples than

herbicides. Four triazine

- herbicide degradation pro ducts

(2

- hydroxyatrazine, deisopropylatrazine, deethylatrazine,

and desethyl

- deisopropylatrazine) were detected in more

than 60 percent of both the raw and finished

- water

samples. None of the herbicides were detected in finished

water at a concentration gr eater than a National drinking

water criterion.

Insecticides were detected less frequently in water

samples than herbicides. Diazinon and chlorpyrifos were

the two most frequently detected insecticides (detected in

35.3 percent and 5.3 percent of the raw

- w ater samples,

respectively). Neither diazinon, chlorpyrifos, nor

malathion, three organophosphorus insecticides, were

detected in any finished

- water samples. Several studies

have shown that organophosphorus compounds are readily

oxidized in the presence of chlorine, with the oxidative

products of these compounds being diazinon, chlorpyrifos

oxygen analog, and malaoxon. Malaoxon, the principal

oxidative transformation product of malathion, was

detected in 11 finished

- water samples and none of the

raw

- water s amples. In three of the samples where

malaoxon was detected in finished water, the

corresponding intake sample showed measurable

concentrations of malathion. Chlorpyrifos oxygen analog

was not detected in any water sample, and diazoxon was

not included as an analyte on any of the three methods.28 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

## Selected References

Adnan, A., and Yurdun, T, 1999, Residues of

organochlorine pesticides in water sources of

Istanbul: Water, Air, and Soil Pollution, v. 111, p.

385

- 398.

Aizawa, T., Magara, Y., Takagi, H., and So una, F., 1994,

Chlorination by

- products of pesticides in drinking

water: Water Supply v. 12, nos 1

- 2, p. SS 11

- 6

– SS

11

- 9.

Eckhardt, D.A., Kappel, W. M., Coon, W. F., and Phillips,

P. J., 1999, Herbicides and their metabolites in

Cayuga Lake and its tribu taries, New York, in

Morganwalp, D.W., and Buxton, H.T., eds., U.S.

Geological Survey Toxic Substances Hydrology

Program

- Proceedings of the Technical Meeting,

Charleston, South Carolina, March 1999: U.S.

Geological Survey Water

- Resources Investigations

R eport 99

- 4018.

Fishman, M.J., ed., 1993, Methods of analysis by the U.S.

Geological Survey National Water Quality

Laboratory

-- Determination of inorganic and organic

constituents in water and fluvial sediments: U.S.

Geological Survey Open

- File Report 93

- 125 , 217 p.

Friedman, L.C., and Erdmann, D.E., 1982, Quality

assurance practices for the chemical and biological

analyses of water and fluvial sediments: U.S.

Geological Survey Techniques of Water

- Resources

Investigations, book 5, chap. A6, 181 p.

Furlong, E. T., Anderson, B. D., Werner, S. L., Soliven, P.

P., Coffey, L. J., and Burkhardt, M. R., 2001,

Methods of analysis by the U.S. Geological Survey

National Water Quality Laboratory

— Determination

of pesticides in water by graphitized carbon

- based

solid

- pha se extraction and high

- performance liquid

chromatography/mass spectrometry: U.S. Geological

Survey Water

- Resources Investigations Report 01

- 4134, 73 p.

Gianessi, L. P., and Anderson, J. E., 1996. Pesticide use in

crop production: National data report. Wash ington,

D.C., National Center for Food and Agricultural

Policy, [variously paged].

Gilliom, R. J. and Thelin, G. P., 1997. Classification and

mapping of agricultural land for National water

Quality assessment: U. S. Geological Survey Circular

1131, 70 pp.

International Life Sciences Institute, 1998: Assessment of

methods to estimate pesticide concentrations in

dinking water sources: Washington, D.C.,

International Life Sciences Institute, Risk Science

Institute, Larson, S. J., Gilliom R. J., and Capel, P. D., 1998,

Pesticides in streams of the United States

-- Initial

results from the National Water

- Quality Assessment

Program: U.S. Geological Survey Water

- Resources

Investigations Report 98

- 4222, 99 p.

Martin, J. D., 1999, Quality of pesticide data for

enviro nmental water samples collected for the

National Water

- Quality Assessment Program, 1992

- 1996, and examples of the use of quality

- control

information in water

- quality assessments: U.S.

Geological Survey , accessed November 15, 2001, at

URL http://ca.water.u sgs.gov/pnsp/rep/qcsummary.

Mueller, D. K., Martin, J. D., and Lopes, T. J., 1997,

Quality

- control design for surface

- water sampling in

the National Water

- Quality Assessment Program:

U.S. Geological Survey Open

- File Report 97

- 223, 17

p.

Phillips, P. J., Ec khardt, D. A., Smith, M. A., and

Rosenmann, L., 1999, Pesticides and their metabolites

in selected surface

- water public supplies in New York

State: U.S. Geological Survey Water

- Resources

Investigations Report 00

- 4119, 17 p.

Pirkey, K.D., and Glodt, S.R., 1 998, Quality control at the

U.S. Geological Survey National Water Quality

Laboratory: U.S. Geological Survey Fact Sheet FS

026

- 98, 4 p.

Pritt, J.W., and Raese, J.W., 1995, Quality

assurance/quality control manual

-- National Water

Quality Laboratory: U.S. Ge ological Survey Open

File Report 95

- 443, 35 p.

Sandstrom, M. W., Stroppel, M. E., Foreman, W. T., and

Schroeder, M. P., 2001, Methods of analysis by the

U.S. Geological Survey National Water Quality

Laboratory

— Determination of moderate

- use

pesticides and selected degradates in water by C

- 18

solid

- phase extraction and gas chromatography/mass

spectrometry: U.S. Geological Survey Water

Resources Investigations Report 01

- 4098, 70 p.

Shelton, L. R., 1994, Field guide for collecting and

processing stream

- water samples for the National

Water

- Quality Assessment Program: U.S. Geological

Survey Open

- File Report 94

- 455, 42 p.

Thelin, G. P., and Gianessi, L. P., 2000, Methods for

estimating pesticide use for county areas in the

conterminous United States: U.S. Geologi cal Survey

Open

- File Report 00

- 250, 62 p.

U.S. Army Corps of Engineers, 1996, National Inventory

of Dams, Washington, D.C., [CD

- ROM].

U.S. Department of Commerce, 1995, 1992 census of

agriculture: Washington, D.C. [CD

- ROM, dBase

format].Summary of Results from a Pilot Monitoring Program 29

U.S. Environmental Protection Agency, 1998, Proposed

methods for basin

- scale estimation of pesticide

concentrations in flowing water and reservoirs for

tolerance reassessment: U.S. Environmental

Protection Agency Office of Pesticide Programs

Science Advisory Panel, July 29

- 30, 1998, [variously

paged].

U.S. Environmental Protection Agency, 1998, Information

available from the Safe Drinking Water Information

System; U.S. Environmental Protection Agency

Office of Water Fact Sheet, EPA 816

- F

- 98

- 006, 2 p.

U.S. Geological Survey,

1998, Policy for the approval of

U.S. Geological Survey water

- quality analytical

methods: Office of Water Quality Technical

Memorandum No. 98.05,accessed June, 10, 2000, at

URL

http://water.usgs.gov/admin/memo/QW/qw98.05.html.

Vogelmann, J.E., Howard, S. M., Yang, L., Larson, C.R.,

Wylie, B.K., Van Driel, N., 2001. Completion of the

1990s National Land Cover Data Set for the

Conterminous United States from Landsat thematic

mapper data and ancillary data sources:

Photogrammetric Engineering and Remote Sensi ng,

67:650

- 652.

Wilde, F.D., Radtke, D.B., Gibs, Jacob, and Iwatsubo,

R.T., 1998, National field manual for the collection of

water

- quality data

-- Preparations for water sampling:

U.S. Geological Survey Techniques of Water

Resources Investigations, book 9, chap. A1

- A5,

[variously paged].

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 an d capillary

- column gas

chromatography/mass spectrometry with selected

- ion

monitoring: U.S. Geological Survey Open

- File Report

95

- 181, 60 p30 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

## Supplemental TablesSummary of Results from a Pilot Monitoring Program 31



### Table 11. Statistical summary of pesticides and degradates detected in water samples from the water

suppl y intake monitoring site at Canyon Reservoir near Elsinore, California

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high perform ance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Prometon 8 8(1) 100 0.025 0.028 0.028

Simazine 8 8 100 0.078 0. 091 0.091

Diazinon 8 7 87.5 0.015 0.045 0.045

Tebuthiuron 8 6(6) 75.0 0.007 0.012 0.012

Atrazine 8 4(2) 50.0 0.002 0.006 0.006

Dacthal 8 4(4) 50.0 0.001 0.003 0.003

Metolachlor 8 3(1) 37.5

--- 0.005 0.005

Tri

- allate 8 1(1) 12.5

--- 0.002 0.002

Trifluralin 8 1(1) 12.5

--- 0.002 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 8 8 100 0.044 0.061 0.061

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Sulfomet uron

- methyl 8 8(3) 100 0.098 0.131 0.131

Diuron 8 7 87.5 0.340 0.540 0.540

3(4

- chlorophenyl)

- 1

- methyl urea 8 5(5) 62.5 0.008 0.026 0.026

Desethyl desisopropylatrazine 8 5(5) 62.5 0.005 0.011 0.011

2

- Hydroxyatrazine 8 3(3) 37.5

--- 0.028 0.028

Deisopropylat razine 8 3(3) 37.5

--- 0.019 0.019

Tebuthiuron 8 3(3) 37.5

--- 0.011 0.011

Bromacil 8 1(1) 12.5

--- 0.005 0.005

Caffeine* 8 1(1) 12.5

--- 0.026 0.026

Dicamba 8 1(1) 12.5

--- 0.090 0.090

MCPA 8 1(1) 12.5

--- 0.011 0.011

Norflurazon 8 1 12.5

--- 0.414 0.414



### * Caffeine is not a pesticide compound, however it is included in this method.32 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 12. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at Elsinore Valley Municipal Water District, California

[Con centrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of p esticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Prometon 8 8(3) 100 0.022 0.030 0.030

Simazine 8 8 100 0.062 0.078 0.078

Atrazine 8 4(3) 50.0 0.002 0.005 0.005

Tebuthiuron 8 4(3) 50.0 0 .003 0.018 0.018

Dacthal 8 2(2) 25.0

--- 0.002 0.002

Metolachlor 8 1 12.5

--- 0.003 0.003

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 8 2(2) 25.0

--- 0.028 0.028

Desethyl desisopropylatrazine 8 2(2) 2 5.0

--- 0.013 0.013

Tebuthiuron 8 2(2) 25.0

--- 0.008 0.008Summary of Results from a Pilot Monitoring Program 33



### Table 13. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Eagle Creek Reservoir, Indiana

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concen trations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses e stimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 48 48 100 1.050 1.840 2.140

Deethylatrazine 48 48(48) 100 0.091 0.198 0.290

Metolachlor 48 48 100 0.308 0.765 0.950

Prometon 48 47(29) 97.9 0.016 0.030 0.034

Acetoch lor 48 41 85.4 0.060 0.119 0.188

Simazine 48 38 79.2 0.018 0.025 0.028

Cyanazine 48 30 62.5 0.008 0.028 0.035

Tebuthiuron 48 23(16) 47.9

--- 0.010 0.012

Diazinon 48 19(6) 39.6

--- 0.008 0.010

Metribuzin 48 19 39.6

--- 0.020 0.025

Alachlor 48 12(1) 25.0

--- 0.010 0.014

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 48 9(8) 18.8

--- 0.004 0.014

2

- [2

- Ethyl

- 6

- methylphenyl)

Amino]

- 1

- propan 48 1(1) 2.1

--- --- 0.007

cis

- Propiconazol 48 1(1) 2.1

--- --- 0.005

Fenamiphos sulfoxide 48 1 2.1

--- --- 0.033

trans

- Propiconazol 48 1(1) 2.1

--- --- 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atrazine 48 48(25) 100 0.891 1.423 2.280

Deethylatrazine 48 48(34) 100 0.1 12 0.211 0.303

2

- Hydroxyatrazine 48 47(47) 97.9 0.552 0.878 1.335

Deisopropylatrazine 48 45(44) 93.8 0.030 0.074 0.097

Metalaxyl 48 44(44) 91.7 0.011 0.025 0.030

2,4

- D 48 42(9) 87.5 0.120 0.192 0.356

Desethyl desisopropylatrazine 48 42(37) 87.5 0.028 0.06 8 0.106

Chlorimuron

- ethyl 48 38(33) 79.2 0.018 0.037 0.058

Tebuthiuron 48 38(38) 79.2 0.003 0.007 0.010

Diuron 48 36(36) 75.0 0.030 0.055 0.065

2,4

- D methyl ester 48 34(34) 70.8 0.017 0.044 0.067

Bentazon 48 31(31) 64.6 0.008 0.021 0.026

Dicamba 48 22(13) 45.8

--- 0.117 0.161

Clopyralid 48 20(7) 41.7

--- 0.079 0.170

Caffeine* 48 16(16) 33.3

--- 0.023 0.034

Bromacil 48 12(12) 25.0

--- 0.023 0.051

MCPA 48 5(4) 10.4

--- 0.011 0.121

Diphenamid 48 3(3) 6.3

--- --- 0.004

Flumetsulam 48 3(3) 6.3

--- --- 0.059

Imaz aquin 48 2(2) 4.2

--- --- 0.060

Sulfometuron

- methyl 48 2(2) 4.2

--- --- 0.009

Metsulfuron

- methyl 48 1(1) 2.1

--- --- 0.002

Triclopyr 48 1(1) 2.1

--- --- 0.037



### * Caffeine is not a pesticide compound, however it is included in this method.34 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 14. Statistical summa ry of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Eagle Creek Reservoir, Indiana

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- M S, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with l ow and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 11 11 100 1.080 1.530 1.560

Cyanazine 11 11 100 0.015 0.017 0.021

Deethylatrazine 11 11(11) 100 0.120 0.200 0.208

Metolachlor 11 11 100 0.334 0.409 0.433

Prometon 11 10(9) 90.9 0.012 0.018 0.020

Acetochlor 11 9 81.8 0.059 0.108 0.132

Simazine 11 9 81.8 0.013 0.017 0.017

Metribuzin 11 6 54.5 0.009 0.014 0.025

Tebuthiuron 11 3(1) 27.3

--- 0.011 0.011

Alachlor 11 2(1) 18.2

--- 0.003 0.004

Diazinon 11 2(2) 18.2

--- 0.003 0.004

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisio nal method 9002)

3,4

- Dichloroaniline 11 1(1) 9.1

--- --- 0.007

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2,4

- D 11 11(4) 100 0.166 0.221 0.319

2

- Hydroxyatrazine 11 11(11) 100 0.692 1.017 1.619

Atrazine 11 11(7) 100 0. 848 1.198 1.392

Deethylatrazine 11 11(7) 100 0.110 0.198 0.200

Deisopropylatrazine 11 11(11) 100 0.026 0.046 0.054

Desethyl desisopropylatrazine 11 10(10) 90.9 0.027 0.058 0.066

Metalaxyl 11 10(10) 90.9 0.012 0.024 0.028

2,4

- D methyl ester 11 7(6) 63.6 0 .022 0.078 0.165

Chlorimuron

- ethyl 11 7(6) 63.6 0.024 0.033 0.041

Tebuthiuron 11 7(7) 63.6 0.003 0.007 0.010

Bentazon 11 5(5) 45.5

--- 0.011 0.011

Diuron 11 5(5) 45.5

--- 0.030 0.052

Dicamba 11 4(4) 36.4

--- 0.060 0.062

Caffeine* 11 2(2) 18.2

--- 0.016 0.0 30

Clopyralid 11 2(1) 18.2

--- 0.040 0.053

Bromacil 11 1(1) 9.1

--- --- 0.028



### * Caffeine is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 35



### Table 15. Statistical summary of pesticides and degradates detected in water samples from the finished

wate r monitoring site at Indianapolis Water Company, Indiana

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid ch romatography

–

mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detect ions Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 22 22 100 0.830 1.490 1.700

Deethylatrazine 22 22(22) 100 0.097 0.2 20 0.253

Metolachlor 22 22 100 0.145 0.360 0.661

Prometon 22 22(10) 100 0.019 0.028 0.032

Simazine 22 19 86.4 0.017 0.022 0.025

Acetochlor 22 13 59.1 0.018 0.105 0.121

Cyanazine 22 11 50.0 0.003 0.023 0.030

Tebuthiuron 22 6(5) 27.3

--- 0.009 0.011

Alachlor 22 3 13.6

--- 0.005 0.012

Fonofos 22 2 9.1

--- --- 0.023

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 22 1(1) 4.5

--- --- 0.003

Fenamiphos sulfoxide 22 1(1) 4.5

--- --- 0.022

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 22 22(22) 100 0.386 0.918 1.525

Deethylatrazine 22 22(14) 100 0.148 0.229 0.242

Atrazine 22 21(9) 95.5 0.575 1.123 1.519

2,4

- D 22 20(3) 90.9 0.109 0.185 0.317

Deisoprop ylatrazine 22 20(19) 90.9 0.035 0.084 0.087

Desethyl desisopropylatrazine 22 18(15) 81.8 0.031 0.079 0.083

Metalaxyl 22 17(17) 77.3 0.012 0.022 0.026

2,4

- D methyl ester 22 16(15) 72.7 0.018 0.042 0.087

Dicamba 22 12(9) 54.5 0.016 0.110 0.119

Diuron 22 10( 10) 45.5

--- 0.024 0.026

Tebuthiuron 22 9(9) 40.9

--- 0.006 0.011

Bentazon 22 7(7) 31.8

--- 0.010 0.016

Caffeine* 22 4(4) 18.2

--- 0.010 0.026

Clopyralid 22 3(2) 13.6

--- 0.030 0.059

Diphenamid 22 3(3) 13.6

--- 0.003 0.006

Bromoxynil 22 1(1) 4.5

--- --- 0. 011

Chlorimuron

- ethyl 22 1(1) 4.5

--- --- 0.040

Flumetsulam 22 1(1) 4.5

--- --- 0.030

MCPA 22 1 4.5

--- --- 0.077

Oryzalin 22 1 4.5

--- --- 0.071

Propoxur 22 1 4.5

--- --- 0.823



### * Caffeine is not a pesticide compound, however it is included in this method36 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 16. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Lake Bruin, Louisiana

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for comp ounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 22 22 100 0.848 0.991 1.020

Cyanazine 22 22 100 0.173 0.238 0.332

Deethylatrazine 22 22(22) 100 0.156 0.188 0.195

Simazine 22 22 100 0.121 0.164 0.184

Metolachlor 22 21 95.5 0.013 0.026 0.033

Tebuthiuron 22 7(7) 31.8

--- 0.006 0.009

Prometon 22 6(6) 27.3

--- 0.005 0.008

Malathion 22 5 22.7

--- 0.023 0.106

Chlorpyrifos 22 3 13.6

--- 0.005 0.008

Trifluralin 22 3(3) 13.6

--- 0.002 0.002

Terbacil 22 2(2) 9.1

--- --- 0.054

Dacthal 22 1 4.5

--- --- 0.014

Diazinon 22 1 4.5

--- --- 0.010

EP TC 22 1(1) 4.5

--- --- 0.011

Parathion

- methyl 22 1 4.5

--- --- 0.061

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Prometryn 20 20 100 0.031 0.039 0.041

3

- Trifluoromethylaniline 20 12(11) 60.0 0.003 0.007 0.008

3,4

- Dichloroaniline 20 8(7) 40.0

--- 0.007 0.011

2,5

- Dichloroaniline 20 1 5.0

--- --- 0.011

2

- [2

- Ethyl

- 6

- methylphenyl)

amino]

- 1

- propanal 20 1(1) 5.0

--- --- 0.074

Dimethoate 20 1 5.0

--- --- 0.007

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL pr ovisional method 9060)

2

- Hydroxyatrazine 21 21(20) 100 0.483 0.970 1.044

Atrazine 21 21(4) 100 0.549 1.104 1.698

Deethylatrazine 21 21(15) 100 0.099 0.121 0.172

Deisopropylatrazine 21 21(20) 100 0.043 0.061 0.131

Fluometuron 21 21(2) 100 0.157 0.238 0.26 4

2,4

- D 21 20(5) 95.2 0.085 0.140 0.180

Diuron 21 19(15) 90.5 0.045 0.101 0.139

Desethyl desisopropylatrazine 21 12(12) 57.1 0.006 0.019 0.027

2,4

- D methyl ester 21 10(10) 47.6

--- 0.027 0.051

Metalaxyl 21 6(6) 28.6

--- 0.005 0.040

Norflurazon 21 5(5) 23. 8

--- 0.005 0.011

Tebuthiuron 21 4(4) 19.0

--- 0.003 0.004

Dicamba 21 2(2) 9.5

--- --- 0.039

Imazethapyr 19 1(1) 5.3

--- --- 0.004

Bromacil 21 1(1) 4.8

--- --- 0.481

Caffeine* 21 1 4.8

--- --- 0.143

Siduron 21 1(1) 4.8

--- --- 0.003



### * Caffeine is not a pes

ticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 37



### Table 17. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Lake Bruin, Louisiana

[Concentrations shown in micrograms per liter;

--- indic ates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantif ied less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in pe rcent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 4 4 100 0.972 1.000 1.000

Cyanazine 4 4 100 0.126 0.139 0.139

Deethylatrazine 4 4(4) 100 0.110 0.154 0.154

Metolachlor 4 4 100 0.028 0.032 0.032

Simazine 4 4 100 0.158 0.162 0.162

Chlorpyrifos 4 3 75.0 0.005 0.006 0.006

Trifluralin 4 2(2) 50.0 0.001 0.002 0.002

Prometon 4 1(1) 25.0

--- 0.003 0.003

Tebuthiuron 4 1(1) 25.0

--- 0.009 0.009

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- D ichloroaniline 3 3(2) 100 0.006 0.008 0.008

Prometryn 3 3 100 0.024 0.024 0.024

3

- Trifluoromethylaniline 3 1(1) 33.3

--- 0.007 0.007

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2,4

- D 4 4 100 0.099 0.142 0.142

2

- Hydroxya trazine 4 4(4) 100 0.727 0.865 0.865

Atrazine 4 4(3) 100 0.934 1.243 1.243

Deethylatrazine 4 4(4) 100 0.096 0.147 0.147

Deisopropylatrazine 4 4(4) 100 0.060 0.070 0.070

Desethyl desisopropylatrazine 4 4(4) 100 0.008 0.015 0.015

Diuron 4 4(4) 100 0.041 0. 060 0.060

Fluometuron 4 4 100 0.231 0.247 0.247

2,4

- D methyl ester 4 3(3) 75.0 0.008 0.013 0.013

Metalaxyl 4 2(2) 50.0 0.001 0.004 0.004

Norflurazon 4 1(1) 25.0

--- 0.009 0.00938 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 18. Statistical summary of pesticides and degradates detected in water samples f rom the finished

water monitoring site at Tensas Water Distribution Association, Inc., Louisiana

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass

spectrome try; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on me thod performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 21 21 100 0.733 0.832 0.851

Cyanazine 21 21 100 0.117 0.170 0.355

Deethylatrazine 21 21(21) 100 0.134 0.170 0.194

Simazine 21 21 100 0.102 0.138 0.173

Metolachlor 21 19(1) 90.5 0.011 0.023 0.027

Prometon 21 7(7) 33.3

--- 0.005 0.007

Tebuthiuron 21 5(5) 23.8

--- 0.004 0.008

Dacthal 21 1(1) 4.8

--- --- 0.004

Trifluralin 21 1(1) 4.8

--- --- 0.002

p,p'

- DDE 21 1(1) 4.8

--- --- 0.001

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Malaoxon 21 11(3) 52.4 0.008 0.128 0.556

4

- Chloro

- 2

- methylphenol 21 4(4) 19.0

--- 0.006 0.007

4,4'

- Dichlorobenzophenone 21 2(2) 9.5

--- --- 0.003

Isofenphos 21 1(1) 4.8

--- --- 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 22 22(22) 100 0.449 1.045 1.172

Atrazin e 22 22(5) 100 0.389 0.699 0.840

2,4

- D 22 21(10) 95.5 0.077 0.114 0.124

Deethylatrazine 22 20(20) 90.9 0.049 0.078 0.091

Deisopropylatrazine 22 18(17) 81.8 0.022 0.065 0.085

Fluometuron 22 18(16) 81.8 0.031 0.077 0.100

2,4

- D methyl ester 22 14(14) 63.6 0 .009 0.021 0.045

Desethyl desisopropylatrazine 22 11(11) 50.0

--- 0.018 0.028

Bromoxynil 22 3(3) 13.6

--- 0.012 0.021

Dicamba 22 2(2) 9.1

--- --- 0.042

Metalaxyl 22 2(2) 9.1

--- --- 0.005

Tebuthiuron 22 1(1) 4.5

--- --- 0.002Summary of Results from a Pilot Monitoring Program 39



### Table 19. Statistical summary of pest icides and degradates detected in water samples from the water

supply intake monitoring site at Higginsville Reservoir, Missouri

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atra zine 40 40 100 2.600 5.880 11.600

Deethylatrazine 40 40(40) 100 0.410 0.624 0.771

Simazine 40 40(2) 100 0.199 0.634 0.769

Metolachlor 40 39 97.5 0.334 2.250 3.320

Prometon 40 37(26) 92.5 0.013 0.024 0.026

Alachlor 40 31(2) 77.5 0.012 0.394 0.655

Cyanazine 40 26(1) 65.0 0.008 0.021 0.024

Acetochlor 40 22 55.0 0.008 0.027 0.031

Diazinon 40 14 35.0

--- 0.011 0.022

Metribuzin 39 9 23.1

--- 0.083 0.291

2,6

- Diethylaniline 40 1(1) 2.5

--- --- 0.001

Azinphos

- methyl 40 1(1) 2.5

--- --- 0.034

Carbaryl 40 1(1) 2.5

-- - --- 0.008

Chlorpyrifos 40 1 2.5

--- --- 0.034

Dacthal 40 1(1) 2.5

--- --- 0.002

Malathion 40 1 2.5

--- --- 0.007

Tebuthiuron 40 1(1) 2.5

--- --- 0.003

Terbacil 40 1(1) 2.5

--- --- 0.007

p,p'

- DDE 40 1(1) 2.5

--- --- 0.003

Analysis of Moderate

- Use Pesti cides and Degradates by GC

- MS (NWQL provisional method 9002)

Prometryn 38 12(12) 31.6

--- 0.004 0.005

2,5

- Dichloroaniline 38 9(2) 23.7

--- 0.011 0.017

2

- Chloro

- 2,6

- diethylacetanilide 38 4 10.5

--- 0.010 0.012

Myclobutanil 38 2(1) 5.3

--- --- 0.015

4

- (Hydro xymethyl)

pendimethalin 38 2(2) 5.3

--- --- 0.016

Tebupirimphos 38 2(2) 5.3

--- --- 0.007

1

- Naphthol 38 1(1) 2.6

--- --- 0.228

2

- [2

- Ethyl

- 6

- methylphenyl)

amino]

- 1

- propanal 38 1(1) 2.6

--- --- 0.010

3,4

- Dichloroaniline 38 1 2.6

--- --- 0.011

Fenamiphos sulf

oxide 38 1(1) 2.6

--- --- 0.008

Methidathion (Supracide) 38 1 2.6

--- --- 0.010

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 36 36(36) 100 1.010 1.612 2.058

Atrazine 36 36(34) 100 1.492 3.223 6.176

De ethylatrazine 36 35(14) 97.2 0.292 0.399 0.546

Deisopropylatrazine 36 35(17) 97.2 0.120 0.201 0.260

Metalaxyl 36 35(27) 97.2 0.033 0.077 0.104

Desethyl desisopropylatrazine 36 28(20) 77.8 0.039 0.088 0.092

2,4

- D 36 23(18) 63.9 0.037 0.078 0.133

Caffeine* 36 16(6) 44.4

--- 0.179 0.435



### * Caffeine is not a pesticide compound, however it is included in this method.40 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 19. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Higginsville Reservoir, Missouri

— continued

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectr

ometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 t h Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

-- Continued

2,4

- D methyl ester 36 7(7) 19.4

--- 0.018 0.041

Bentazon 36 4(4 ) 11.1

--- 0.003 0.008

Chlorimuron

- ethyl 36 4(4) 11.1

--- 0.006 0.018

Dicamba 36 4(3) 11.1

--- 0.047 0.126

Flumetsulam 36 4(4) 11.1

--- 0.006 0.027

Acifluorfen 35 3(3) 8.6

--- --- 0.022

Imazaquin 36 1(1) 2.8

--- --- 0.012

MCPA 36 1 2.8

--- --- 0.061

Nicosu lfuron 36 1(1) 2.8

--- --- 0.017

Propoxur 36 1(1) 2.8

--- --- 0.005

Tebuthiuron 36 1(1) 2.8

--- --- 0.027Summary of Results from a Pilot Monitoring Program 41



### Table 20. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Higginsville Reservoir, Mis souri

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified esti mates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Alachlor 11 11(1) 100 0.182 0.482 0.643

Atrazine 11 11 100 3.140 5.690 6.200

Deethylatrazine 11 11(11) 100 0.429 0.728 0.754

Me tolachlor 11 11 100 1.380 2.870 3.580

Prometon 11 10(4) 90.9 0.019 0.025 0.028

Simazine 11 10 90.9 0.397 0.603 0.805

Acetochlor 11 8 72.7 0.013 0.023 0.029

Cyanazine 11 8(1) 72.7 0.013 0.021 0.021

Diazinon 11 7 63.6 0.006 0.015 0.018

Metribuzin 10 4 40.0

- -- 0.202 0.265

Tebuthiuron 11 1(1) 9.1

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

2

- Chloro

- 2,6

- diethylacetanilide 9 3 33.3

--- 0.012 0.012

Terbuthylazine 8 1(1) 12.5

--- 1.500 1.500

3,4

- Dichlor

oaniline 9 1 11.1

--- 0.070 0.070

Myclobutanil 9 1(1) 11.1

--- 0.006 0.006

Tebupirimphos 9 1(1) 11.1

--- 0.005 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atrazine 10 10(10) 100 2.408 3.904 4.068

Deethylatrazine 10 10(6) 100 0.235 0.460 0.577

Deisopropylatrazine 10 10(9) 100 0.114 0.201 0.258

2

- Hydroxyatrazine 10 9(9) 90.0 1.276 1.951 2.175

Desethyl desisopropylatrazine 10 9(7) 90.0 0.040 0.301 0.514

Metalaxyl 10 9(7) 90.0 0.037 0.074 0.077

Caffeine* 10 7(5) 70. 0 0.056 0.130 0.150

2,4

- D 10 4(3) 40.0

--- 0.089 0.115

2,4

- D methyl ester 10 2(2) 20.0

--- 0.011 0.013

Flumetsulam 10 2(2) 20.0

--- 0.021 0.029

Acifluorfen 9 1(1) 11.1

--- 0.029 0.029

Chlorimuron

- ethyl 10 1(1) 10.0

--- 0.013 0.026



### * Caffeine is not a pesti

cide compound, however it is included in this method.42 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 21. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at City of Higginsville Municipal Utilities, Missouri

[Concentrations shown in microg rams per liter;

---

indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- f or concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

a nalyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 25 25 100 0.722 1.190 1.300

Deethylatrazine 25 25(25) 100 0.100 0.249 0.296

Metolachlor 25 25 100 0.063 0.453 0.514

Simazine 25 24 96.0 0.020 0.087 0.092

P rometon 25 19(19) 76.0 0.004 0.010 0.012

Alachlor 25 14(2) 56.0 0.004 0.051 0.056

Cyanazine 25 12(1) 48.0

--- 0.019 0.020

Acetochlor 25 10 40.0

--- 0.011 0.022

Carbaryl 25 1(1) 4.0

--- --- 0.004

Phorate 25 1(1) 4.0

--- --- 0.001

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Azinphos

- methyl

- oxon 20 2(2) 10.0

--- 0.004 0.010

2

- [2

- Ethyl

- 6

- methylphenyl)

amino]

- 1

- propanal 20 1(1) 5.0

--- --- 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional m ethod 9060)

Atrazine 25 25(5) 100 0.269 0.772 1.013

2

- Hydroxyatrazine 25 24(24) 96.0 0.260 0.574 1.210

Deethylatrazine 25 24(23) 96.0 0.042 0.153 0.201

Deisopropylatrazine 25 21(21) 84.0 0.013 0.048 0.071

Metalaxyl 25 21(20) 84.0 0.012 0.042 0.072

Deset hyl desisopropylatrazine 25 17(17) 68.0 0.014 0.029 0.036

2,4

- D 25 9(8) 36.0

--- 0.035 0.131

Caffeine* 25 6(6) 24.0

--- 0.024 0.035

Dicamba 25 2(2) 8.0

--- --- 0.054

Imazethapyr 23 1(1) 4.3

--- --- 0.004

Benomyl 25 1(1) 4.0

--- --- 0.215

Bentazon 25 1(1) 4 .0

--- --- 0.004

Chlorimuron

- ethyl 25 1(1) 4.0

--- --- 0.009

Imazaquin 25 1(1) 4.0

--- --- 0.008

Oryzalin 25 1(1) 4.0

--- --- 0.012



### * Caffeine is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 43



### Table 22. Statistical summary of pesticides and degra dates detected in water samples from the water

supply intake monitoring site at Tar River Reservoir, North Carolina

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatograp hy

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable rec overies based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Deethylatrazine 1 0 10(10) 100 0.006 0.009 0.010

Prometon 10 10(10) 100 0.010 0.014 0.015

Atrazine 10 9 90.0 0.020 0.042 0.043

Metolachlor 10 9 90.0 0.020 0.045 0.046

Simazine 10 8 80.0 0.012 0.019 0.022

Diazinon 10 5(2) 50.0 0.001 0.011 0.012

Carbaryl 10 1(1) 10.0

--- 0.0 02 0.004

Tebuthiuron 10 1 10.0

--- 0.006 0.011

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Fenamiphos sulfone 10 1(1) 10.0

--- 0.002 0.005

Metalaxyl 10 1(1) 10.0

--- 0.003 0.005

Prometryn 10 1(1) 10.0

--- 0. 002 0.004

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 10 7(7) 70.0 0.043 0.102 0.110

Atrazine 10 6(6) 60.0 0.003 0.025 0.027

Bentazon 10 4(4) 40.0

--- 0.083 0.107

Caffeine* 10 4(4) 40.0

--- 0.046 0.05 7

Desethyl desisopropylatrazine 10 3(3) 30.0

--- 0.003 0.003

Fluometuron 10 3(3) 30.0

--- 0.012 0.017

Diuron 10 2(2) 20.0

--- 0.042 0.069

2,4

- D 10 1(1) 10.0

--- 0.009 0.018

Chloramben methyl ester 10 1 10.0

--- 0.063 0.126

Picloram 10 1 10.0

--- 0.037 0.07 5



### * Caffeine is not a pesticide compound, however it is included in this method.44 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 23. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Tar River Reservoir, North Carolina

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide con centrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value perc entile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 1 1 100 0.011 0.011 0.011

Deethylatrazine 1 1(1) 100 0.003 0.003 0.003

Metolachlor 1 1 100 0.009 0.009 0.009

Prometon 1 1(1) 100 0.011 0.011 0.011

Simazine 1 1 100 0.008 0.008 0.008

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 1 1(1) 100 0.015 0.015 0.015

Atrazine 1 1(1) 100 0.008 0.008 0.008

Caffeine* 1 1(1) 100 0.014 0.014 0.014



### * Caffei ne is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 45



### Table 24. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at Tar River Water Treatment Plant, North Carolina

[Concentrations s

hown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide conc entrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value perce ntile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Prometon 10 10(10) 100 0.008 0.013 0.014

Atrazine 10 9 90.0 0.014 0.030 0.034

Deethylatrazine 10 9(9) 90.0 0.007 0.009 0.009

Metolachlor 10 9 90.0 0.0 12 0.016 0.016

Simazine 10 8(1) 80.0 0.008 0.016 0.018

Dacthal 10 1(1) 10.0

--- 0.001 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Fenamiphos sulfone 10 2(1) 20.0

--- 0.011 0.016

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 10 7(7) 70.0 0.048 0.091 0.101

Atrazine 10 6(6) 60.0 0.005 0.018 0.023

Desethyl desisopropylatrazine 10 5(5) 50.0 0.001 0.005 0.007

Metalaxyl 10 2(2) 20.0

--- 0.002 0.003

2,4

- D 1 0 1(1) 10.0

--- 0.017 0.034

3

- Hydroxycarbofuran 10 1(1) 10.0

--- 0.005 0.009

Caffeine* 10 1(1) 10.0

--- 0.015 0.031

Deethylatrazine 10 1(1) 10.0

--- 0.004 0.007

Deisopropylatrazine 10 1(1) 10.0

--- 0.002 0.005

Dicamba 10 1(1) 10.0

--- 0.005 0.011

Fluometu ron 10 1(1) 10.0

--- 0.002 0.003

Neburon 10 1(1) 10.0

--- 0.001 0.002

Triclopyr 10 1(1) 10.0

--- 0.009 0.017



### * Caffeine is not a pesticide compound, however it is included in this method.46 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 25. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at LeRoy Reservoir, New York

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performan ce]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 22 22 100 0.178 0.229 0.490

Deethylatrazi

ne 22 22(22) 100 0.070 0.099 0.127

Metolachlor 22 22 100 0.093 0.243 0.442

Cyanazine 22 16(1) 72.7 0.014 0.049 0.079

Simazine 22 15(2) 68.2 0.005 0.008 0.008

EPTC 22 13(3) 59.1 0.003 0.014 0.037

Alachlor 22 9 40.9

--- 0.065 0.176

Prometon 22 7(7) 31.8

--- 0.007 0.008

Acetochlor 22 2 9.1

--- --- 0.009

2,6

- Diethylaniline 22 1(1) 4.5

--- --- 0.002

Butylate 22 1(1) 4.5

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Disulfoton sulfone 20 1 5.0

--- --- 0. 013

Disulfotone sulfoxide 20 1(1) 5.0

--- --- 0.006

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 20 20(20) 100 0.299 0.767 1.083

Atrazine 20 20(10) 100 0.103 0.175 0.219

Deethylatrazine 20 20(20) 100 0.047 0.074 0.091

Metalaxyl 20 17(16) 85.0 0.026 0.050 0.072

Deisopropylatrazine 20 14(14) 70.0 0.013 0.031 0.041

Desethyl desisopropylatrazine 20 13(13) 65.0 0.018 0.043 0.052

Bentazon 20 9(9) 45.0

--- 0.120 0.344

2,4

- D 20 3(3) 15.0

--- 0.026 0.031

Caffe ine* 20 3(3) 15.0

--- 0.014 0.024

Imazaquin 20 3(3) 15.0

--- 0.008 0.022

Flumetsulam 20 2(2) 10.0

--- 0.012 0.088

2,4

- D methyl ester 20 1(1) 5.0

--- --- 0.006

Aldicarb sulfone 20 1(1) 5.0

--- --- 0.007

Dicamba 20 1(1) 5.0

--- --- 0.031

MCPA 20 1(1) 5.0

--- --- 0.018

Metsulfuron

- methyl 20 1 5.0

--- --- 0.148

Neburon 20 1(1) 5.0

--- --- 0.009

Oryzalin 20 1 5.0

--- --- 0.071

Picloram 20 1(1) 5.0

--- --- 1.441



### * Caffeine is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 47



### Table 26. Statistical summary o f pesticides and degradates detected in water samples from the finished

water monitoring site at Village of LeRoy Water Department, New York

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level ; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL metho d 2001)

Atrazine 21 21 100 0.162 0.225 0.459

Deethylatrazine 21 21(21) 100 0.072 0.110 0.151

Metolachlor 21 21 100 0.093 0.222 0.410

Cyanazine 21 13 61.9 0.015 0.051 0.072

Alachlor 21 8 38.1

--- 0.055 0.148

Simazine 21 7(2) 33.3

--- 0.008 0.008

Prometon 21 2(2) 9.5

--- --- 0.008

Fonofos 20 1 5.0

--- --- 0.009

2,6

- Diethylaniline 21 1(1) 4.8

--- --- 0.002

Acetochlor 21 1 4.8

--- --- 0.014

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Azinphos

- methyl

- oxon 20 2(2) 1 0.0

--- 0.013 0.026

2,5

- Dichloroaniline 20 1(1) 5.0

--- --- 0.004

3,5

- Dichloroaniline 20 1 5.0

--- --- 0.009

Iprodione 20 1(1) 5.0

--- --- 0.023

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 20 20(20) 10 0 0.303 0.913 1.175

Atrazine 20 20(10) 100 0.115 0.159 0.199

Deethylatrazine 20 20(20) 100 0.039 0.067 0.258

Metalaxyl 20 18(18) 90.0 0.022 0.047 0.055

Desethyl desisopropylatrazine 20 12(12) 60.0 0.013 0.037 0.043

Deisopropylatrazine 20 11(11) 55.0 0.0 11 0.037 0.059

Flumetsulam 20 3(3) 15.0

--- 0.028 0.037

Imazaquin 20 3(3) 15.0

--- 0.011 0.111

2,4

- D 20 2(2) 10.0

--- 0.011 0.024

2,4

- DB 20 2(2) 10.0

--- 0.003 0.011

Bentazon 20 2(2) 10.0

--- 0.004 0.011

Dichlorprop 20 1(1) 5.0

--- --- 0.018

Benomyl 20 1(1 ) 5.0

--- --- 0.005

Dicamba 20 1(1) 5.0

--- --- 0.018

Triclopyr 20 1(1) 5.0

--- --- 0.04148 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 27. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at East Fork Lake, Ohio

[Concentrations show

n in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concent rations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percenti le value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Acetochlor 21 21 100 0.031 0.136 0.284

Alachlor 21 21 100 0.014 0.053 0.105

Atrazine 21 21 100 0.230 3.240 3.860

Cyanazine 21 21 100 0.149 0.210 0.233

De ethylatrazine 21 21(21) 100 0.074 0.448 0.668

Metolachlor 21 21 100 0.294 0.682 1.010

Simazine 21 21 100 0.032 0.437 0.625

Metribuzin 21 19 90.5 0.012 0.042 0.095

Tebuthiuron 21 17(6) 81.0 0.011 0.015 0.015

Prometon 21 14(14) 66.7 0.007 0.013 0.013

Diazino n 21 10(1) 47.6

--- 0.013 0.015

Chlorpyrifos 21 2(2) 9.5

--- --- 0.004

Carbaryl 21 1(1) 4.8

--- --- 0.012

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 21 5(5) 23.8

--- 0.004 0.005

2

- [2

- Eth yl

- 6

- methylphenyl)amino]

- 1

- propan 21 1(1) 4.8

--- --- 0.006

Metalaxyl 21 1(1) 4.8

--- --- 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atrazine 19 19(12) 100 0.154 1.888 2.718

Deethylatrazine 19 19(18) 100 0.038 0.381 0.458

Deisopropylatrazine 19 19(18) 100 0.024 0.225 0.269

2

- Hydroxyatrazine 18 17(17) 94.4 0.334 0.543 1.636

Desethyl desisopropylatrazine 19 17(15) 89.5 0.030 0.071 0.134

Metalaxyl 19 14(13) 73.7 0.016 0.045 0.086

2,4

- D 19 13(6) 68.4 0.076 0.120 0 .139

Tebuthiuron 19 13(13) 68.4 0.006 0.010 0.011

Caffeine* 19 10(10) 52.6 0.020 0.035 0.047

Chlorimuron

- ethyl 19 9(7) 47.4

--- 0.042 0.050

2,4

- D methyl ester 19 8(8) 42.1

--- 0.016 0.030

Bentazon 19 7(7) 36.8

--- 0.042 0.079

Imazaquin 19 6(6) 31.6

--- 0.0 65 0.084

Imazethapyr 18 4(4) 22.2

--- 0.084 0.111

Diphenamid 19 3(3) 15.8

--- 0.026 0.038

Acifluorfen 18 2(2) 11.1

--- 0.013 0.015

Diuron 19 2(2) 10.5

--- 0.013 0.020

Picloram 19 1 5.3

--- --- 0.430

Terbacil 19 1(1) 5.3

--- --- 0.013



### * Caffeine is not a p esticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 49



### Table 28. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at East Fork Lake, Ohio

[Concentrations shown in micrograms per liter;

--- ind icates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quant ified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Acetochlor 11 11 100 0.020 0.037 0.041

Alachlor 11 11(1) 100 0.011 0.033 0.129

Atrazine 11 11 100 0.389 0.465 2.390

Cyanazine 11 11 100 0.163 0.178 0.250

Deethylatrazine 11 11(11) 100 0.0 82 0.121 0.182

Metolachlor 11 11 100 0.238 0.449 0.689

Simazine 11 11 100 0.026 0.034 0.035

Tebuthiuron 11 9(3) 81.8 0.011 0.012 0.012

Prometon 11 6(6) 54.5 0.003 0.005 0.007

Metribuzin 11 3 27.3

--- 0.010 0.013

p,p'

- DDE 11 2(2) 18.2

--- 0.001 0.002

Chlorp yrifos 11 1 9.1

--- --- 0.006

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 10 1(1) 10.0

--- 0.002 0.003

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atra zine 11 11(6) 100 0.221 0.331 0.358

Deethylatrazine 11 11(11) 100 0.048 0.057 0.065

Desethyl desisopropylatrazine 11 10(10) 90.9 0.022 0.043 0.045

Metalaxyl 11 10(10) 90.9 0.012 0.023 0.027

2

- Hydroxyatrazine 10 9(9) 90.0 0.428 0.584 0.598

2,4

- D 11 9(9) 81.8 0.042 0.058 0.135

Deisopropylatrazine 11 9(9) 81.8 0.023 0.030 0.033

Tebuthiuron 11 7(7) 63.6 0.002 0.009 0.009

Caffeine* 11 6(6) 54.5 0.027 0.047 0.081

2,4

- D methyl ester 11 5(5) 45.5

--- 0.023 0.033

Chlorimuron

- ethyl 11 4(4) 36.4

--- 0.020 0.021

Ben tazon 11 3(3) 27.3

--- 0.007 0.010

Acifluorfen 10 2(2) 20.0

--- 0.003 0.003

Dinoseb 11 1(1) 9.1

--- --- 0.001

Imazaquin 11 1(1) 9.1

--- --- 0.010



### * Caffeine is not a pesticide compound, however it is included in this method.50 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 29. Statistical summary of pestic ides and degradates detected in water samples from the finished

water monitoring site at Clermont Water Authority, Ohio

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromato graphy

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 21 2 0(2) 95.2 0.095 0.166 0.208

Metolachlor 21 20 95.2 0.041 0.238 0.384

Deethylatrazine 21 18(18) 85.7 0.017 0.061 0.078

Acetochlor 21 15 71.4 0.016 0.032 0.045

Alachlor 21 14(1) 66.7 0.006 0.013 0.027

Simazine 21 14(1) 66.7 0.010 0.020 0.024

Cyanazine 21 10 47.6

--- 0.135 0.211

Prometon 21 5(5) 23.8

--- 0.003 0.007

Tebuthiuron 21 5(5) 23.8

--- 0.009 0.009

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 19 16(16) 84.2 0.059 0.404 0.463

Atrazine 20 16(13) 80.0 0.045 0.123 0.160

Desethyl desisopropylatrazine 20 16(16) 80.0 0.014 0.022 0.030

Deethylatrazine 19 13(13) 68.4 0.008 0.044 0.053

Metalaxyl 20 13(13) 65.0 0.009 0.024 0.025

Deisopropylatrazine 20 8(8) 40.0

--- 0.021 0.032

2,4

- D 20 5(4) 25.0

--- 0.056 0. 089

Imazaquin 20 5(5) 25.0

--- 0.012 0.014

Caffeine* 20 4(4) 20.0

--- 0.021 0.041

Tebuthiuron 20 3(3) 15.0

--- 0.004 0.006

Imazethapyr 19 2(2) 10.5

--- 0.036 0.038

Acifluorfen 19 1(1) 5.3

--- --- 0.016

2,4

- D methyl ester 20 1(1) 5.0

--- --- 0.009

Bentazon 20 1(1) 5.0

--- --- 0.009

Dicamba 20 1(1) 5.0

--- --- 0.025



### * Caffeine is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 51



### Table 30. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Lake Arcadia, Oklahoma

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectr

ometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 t h Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 41 41 100 0.286 0.595 0.745

Deethylatrazine 41 41(41) 100 0.046 0.067 0.095

Prometon 41 41 10 0 0.086 0.113 0.138

Simazine 41 41 100 0.971 1.300 1.520

Diazinon 41 40 97.6 0.051 0.080 0.101

Metolachlor 41 40(2) 97.6 0.012 0.029 0.039

Pronamide 41 34 82.9 0.023 0.038 0.048

Tebuthiuron 41 33(5) 80.5 0.017 0.023 0.024

Dacthal 41 7(7) 17.1

--- 0.002 0. 004

Terbacil 41 4(4) 9.8

--- --- 0.024

Chlorpyrifos 41 2(1) 4.9

--- --- 0.004

Benfluralin 41 1(1) 2.4

--- --- 0.001

p,p'

- DDE 41 1(1) 2.4

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloro aniline 41 31 75.6 0.013 0.022 0.034

2

- [2

- Ethyl

- 6

- methylphenyl)

amino]

- 1

- propanal 41 6(4) 14.6

--- 0.011 0.037

1,4

- Naphthoquinone 41 1(1) 2.4

--- --- 0.005

4

- Chloro

- 2

- methylphenol 41 1(1) 2.4

--- --- 0.003

Azinphos

- methyl

- oxon 41 1 2.4

--- --- 0.263

Isofen phos 41 1(1) 2.4

--- --- 0.007

Metalaxyl 41 1(1) 2.4

--- --- 0.005

Myclobutanil 41 1(1) 2.4

--- --- 0.006

Prometryn 41 1(1) 2.4

--- --- 0.003

Tefluthrin metabolite [R 119364] 41 1(1) 2.4

--- --- 0.004

Analysis of Pesticides and Degradates by HPLC

- MS (NWQ L provisional method 9060)

2

- Hydroxyatrazine 39 39(39) 100 0.099 0.321 0.357

Atrazine 39 39(8) 100 0.199 0.519 0.618

Deisopropylatrazine 39 39(27) 100 0.133 0.223 0.386

Deethylatrazine 39 38(38) 97.4 0.029 0.038 0.051

Diuron 39 38(2) 97.4 0.278 0.379 0.4 35

Caffeine* 39 35(24) 89.7 0.073 0.102 0.133

2,4

- D 39 34(19) 87.2 0.073 0.098 0.154

Tebuthiuron 39 34(34) 87.2 0.008 0.013 0.015

Bromacil 39 28(26) 71.8 0.043 0.084 0.136

Sulfometuron

- methyl 39 28(16) 71.8 0.033 0.126 0.160

Desethyl desisopropylatrazine 3 9 27(22) 69.2 0.034 0.077 0.114

Dicamba 39 22(17) 56.4 0.037 0.105 0.192

Benomyl 39 14(13) 35.9

--- 0.031 0.038

2,4

- D methyl ester 39 8(8) 20.5

--- 0.016 0.041

Metalaxyl 39 6(6) 15.4

--- 0.003 0.351



### * Caffeine is not a pesticide compound, however it is in cluded in this method.52 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 30. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Lake Arcadia, Oklahoma

— continued.

[Concentrations shown in micrograms per liter;

--- indicates va lue reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified les s than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

-- continued

Dichlorprop 39 2(2) 5.1

--- --- 0.036

Bentazon 39 2(2) 5.1

--- --- 0.011

Imazethapyr 38 1(1) 2.6

--- --- 0.103

Clopyralid 39 1(1) 2.6

--- --- 0.024

MCPA 39 1(1) 2.6

--- --- 0.004

Metsulfuron

- methyl 39 1(1) 2.6

--- --- 1.194

Triclopyr 39 1(1) 2.6

--- --- 0.017Summary of Results from a Pilot Monitoring Program 53



### Table 31. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Lake Arcadia, Oklahoma

[Conce ntrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pes ticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, v alue percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 10 10 100 0.299 0.659 0.687

Deethylatrazine 10 10(10) 100 0.032 0.056 0.059

Prometon 10 10(3) 100 0.060 0.104 0.107

Simazine 10 10 100 0.629 1.500 1.580

Metolachlor 10 8 80.0 0.014 0.034 0.038

Tebuthiuron 10 8(3) 80.0 0.012 0.022 0.024

Diazinon 10 7(2) 70.0 0.027 0.096 0.111

Pronamide 10 6 60.0 0.016 0.040 0.045

p,p'

- DDE 10 2(2) 20.0

--- 0.002 0.002

Analysis of Moderate

- Use Pesticide s and Degradates by GC

- MS (NWQL provisional method 9002)

3,4

- Dichloroaniline 10 5(1) 50.0 0.003 0.029 0.031

Azinphos

- methyl

- oxon 10 1 10.0

--- 0.150 0.300

Metalaxyl 10 1(1) 10.0

--- 0.003 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provi sional method 9060)

Atrazine 10 10(6) 100 0.174 0.600 0.659

Deisopropylatrazine 10 10(8) 100 0.048 0.155 0.156

2

- Hydroxyatrazine 10 9(9) 90.0 0.164 0.315 0.346

Desethyl desisopropylatrazine 10 9(9) 90.0 0.013 0.037 0.038

Deethylatrazine 10 8(8) 80.0 0.01 3 0.036 0.037

Diuron 10 8(3) 80.0 0.141 0.425 0.448

Tebuthiuron 10 6(6) 60.0 0.004 0.013 0.015

Bromacil 10 5(5) 50.0 0.016 0.069 0.072

Caffeine* 10 5(2) 50.0 0.025 0.220 0.329

Sulfometuron

- methyl 10 5(1) 50.0 0.045 0.162 0.194

Dicamba 10 3(3) 30.0

--- 0.06 5 0.067

Terbacil 10 2(2) 20.0

--- 0.046 0.051

2,4

- D 10 1(1) 10.0

--- 0.033 0.065

2,4

- DB 10 1 10.0

--- 0.027 0.054

Benomyl 10 1(1) 10.0

--- 0.014 0.027

Metalaxyl 10 1(1) 10.0

--- 0.001 0.002



### * Caffeine is not a pesticide compound, however it is included i n this method.54 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 32. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at Edmonds Water Supply, Oklahoma

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than t he method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pestici des by GC

- MS (NWQL method 2001)

Atrazine 19 19 100 0.269 0.346 0.385

Deethylatrazine 19 19(19) 100 0.040 0.062 0.062

Prometon 19 19 100 0.072 0.084 0.103

Simazine 19 19 100 0.395 0.463 0.571

Metolachlor 19 18 94.7 0.007 0.010 0.012

Tebuthiuron 19 18(2) 94. 7 0.022 0.031 0.032

Pronamide 19 8 42.1

--- 0.012 0.017

Dacthal 19 4(4) 21.1

--- 0.002 0.003

Trifluralin 19 1 5.3

--- --- 0.005

p,p'

- DDE 19 1(1) 5.3

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

2

- [2

- Ethyl

- 6

- methylphenyl)amino]

-

1

- propanol 19 4(4) 21.1

--- 0.005 0.014

Metalaxyl 19 1(1) 5.3

--- --- 0.004

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atrazine 19 19(7) 100 0.163 0.337 0.416

2

- Hydroxyatrazine 19 17 (17) 89.5 0.060 0.308 0.345

Tebuthiuron 19 17(17) 89.5 0.010 0.017 0.018

Deisopropylatrazine 19 15(9) 78.9 0.053 0.137 0.178

Deethylatrazine 19 14(14) 73.7 0.012 0.023 0.037

2,4

- D 19 12(12) 63.2 0.026 0.044 0.054

Desethyl desisopropylatrazine 19 11(11) 57 .9 0.004 0.035 0.039

Dicamba 19 8(8) 42.1

--- 0.049 0.063

Sulfometuron

- methyl 19 6(6) 31.6

--- 0.008 0.024

Oxamyl oxime 19 2(2) 10.5

--- 0.013 0.014

Triclopyr 19 2(2) 10.5

--- 0.012 0.013

Bendiocarb 19 1(1) 5.3

--- --- 0.004

Caffeine* 19 1(1) 5.3

--- --- 0 .009

Clopyralid 19 1(1) 5.3

--- --- 0.027



### * Caffeine is not a pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 55



### Table 33. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Blue Marsh Reservoir, Tulpehocken Creek, Pennsylvania

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detectio n Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 23 23 100 0.094 0.761 1.600

Deethylatrazine 23 23(23) 100 0.104 0.197 0.255

Metol achlor 23 23 100 0.025 0.268 0.520

Simazine 23 22 95.7 0.036 0.092 0.123

Prometon 23 21(21) 91.3 0.009 0.015 0.017

Tebuthiuron 23 11(11) 47.8

--- 0.007 0.009

Acetochlor 23 10 43.5

--- 0.036 0.048

Alachlor 23 10(1) 43.5

--- 0.011 0.021

Cyanazine 23 9(1) 39. 1

--- 0.026 0.037

Diazinon 23 7(1) 30.4

--- 0.007 0.015

Pendimethalin 23 6 26.1

--- 0.022 0.125

Chlorpyrifos 23 5(2) 21.7

--- 0.004 0.012

Carbaryl 23 4(4) 17.4

--- 0.008 0.047

Trifluralin 23 3(3) 13.0

--- 0.001 0.002

p,p'

- DDE 23 3(3) 13.0

--- 0.002 0.002

Carbofuran 23 2(2) 8.7

--- --- 0.019

Dacthal 23 1(1) 4.3

--- --- 0.003

EPTC 23 1(1) 4.3

--- --- 0.002

Linuron 23 1 4.3

--- --- 0.010

Napropamide 23 1(1) 4.3

--- --- 0.003

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional met hod 9002)

Dimethoate 24 3(1) 12.5

--- 0.006 0.022

Endosulfan sulfate 24 3(2) 12.5

--- 0.005 0.009

Tefluthrin metabolite [R 152912] 24 2(1) 8.3

--- --- 0.021

1,4

- Naphthoquinone 24 1(1) 4.2

--- --- 0.004

1

- Naphthol 24 1(1) 4.2

--- --- 0.006

2

- [2

- Ethyl

- 6

- meth ylphenyl)

amino]

- 1

- propanal 24 1(1) 4.2

--- --- 0.006

3,4

- Dichloroaniline 24 1(1) 4.2

--- --- 0.004

Hexazinone 24 1(1) 4.2

--- --- 0.005

Tefluthrin 24 1(1) 4.2

--- --- 0.003

Tefluthrin metabolite [R 119364] 24 1(1) 4.2

--- --- 0.005

Tebupirimphos 24 1(1) 4 .2

--- --- 0.006

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Deethylatrazine 24 24(24) 100 0.063 0.120 0.228

Atrazine 24 23(14) 95.8 0.063 0.553 1.253

2

- Hydroxyatrazine 24 22(22) 91.7 0.073 0.206 0.295

Desethyl desiso propylatrazine 24 22(13) 91.7 0.047 0.079 0.102

Caffeine* 24 15(14) 62.5 0.035 0.074 0.085

Deisopropylatrazine 24 14(14) 58.3 0.011 0.033 0.118

Bentazon 24 8(8) 33.3

--- 0.008 0.013

Bromacil 24 7(7) 29.2

--- 0.012 0.014



### * Caffeine is not a pesticide compou nd, however it is included in this method.56 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 33. Statistical summary of pesticides and degradates detected in water samples from the

water

- supply intake monitoring site at Blue Marsh Reservoir, Tulpehocken Creek, Pennsylvania

—

continued

[Concentrations

shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide co ncentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value per centile value

analyses estimates) in percent value

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

-- continued

2,4

- D 24 5(5) 20.8

--- 0.026 0.056

Benomyl 24 5(5) 20.8

--- 0.016 0.030

Dicamba 24 4(4) 16.7

--- 0.045 0.094

Metalaxyl 24 4(4) 16.7

--- 0.007 0.014

Diuron 24 3(3) 12.5

--- 0.003 0.041

Imazethapyr 21 2(2) 9.5

--- --- 0.041

Imazaquin 23 2(2) 8.7

--- --- 0.351

Carbofuran 24 2(2) 8.3

--- --- 0.010

Tebuthiuron 24 2(2) 8.3

--- --- 0.005

Carbaryl 24 1(1) 4.2

--- --- 0.005

Dinoseb 24 1(1) 4.2

--- --- 0.003

Nicosulfuron 24 1(1) 4.2

--- --- 0.022

Oryzalin 24 1 4.2

--- --- 0.071Summary of Results from a Pilot Monitoring Program 57



### Table 34. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at Western Berks Water Autho rity, Pennsylvania

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),q

ualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

o f (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 23 23 100 0.056 0.470 0.740

Deethylatrazine 23 23(23) 100 0.069 0.119 0.200

Metolachlor 23 23 100 0.015 0. 155 0.245

Simazine 23 22(1) 95.7 0.016 0.039 0.056

Prometon 23 21(21) 91.3 0.008 0.012 0.012

Acetochlor 23 9(1) 39.1

--- 0.016 0.025

Alachlor 23 8(1) 34.8

--- 0.008 0.010

Cyanazine 23 7(1) 30.4

--- 0.014 0.019

Tebuthiuron 23 7(7) 30.4

--- 0.005 0.005

Carbo furan 23 3(3) 13.0

--- 0.008 0.010

Pendimethalin 23 3 13.0

--- 0.006 0.009

p,p'

- DDE 23 2(2) 8.7

--- --- 0.002

Carbaryl 23 1(1) 4.3

--- --- 0.003

EPTC 23 1(1) 4.3

--- --- 0.001

Trifluralin 23 1(1) 4.3

--- --- 0.001

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

Endosulfan sulfate 24 2(2) 8.3

--- --- 0.005

Terbufos

- O

- analogue sulfone 24 2(2) 8.3

--- --- 0.015

1,4

- Naphthoquinone 24 1(1) 4.2

--- --- 0.003

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL prov isional method 9060)

Atrazine 23 23(16) 100 0.034 0.271 0.588

Deethylatrazine 23 23(23) 100 0.035 0.079 0.138

Desethyl desisopropylatrazine 23 22(22) 95.7 0.031 0.046 0.055

2

- Hydroxyatrazine 23 20(20) 87.0 0.044 0.099 0.200

Deisopropylatrazine 23 13(13) 56.5 0.003 0.020 0.042

Caffeine* 23 8(8) 34.8

--- 0.023 0.071

Bentazon 23 5(5) 21.7

--- 0.005 0.011

Metalaxyl 23 4(4) 17.4

--- 0.005 0.007

2,4

- D 23 3(3) 13.0

--- 0.019 0.035

Dicamba 23 3(3) 13.0

--- 0.019 0.055

Bromacil 23 1(1) 4.3

--- --- 0.481

Carbofura n 23 1(1) 4.3

--- --- 0.004

Dinoseb 23 1(1) 4.3

--- --- 0.002

Metsulfuron

- methyl 23 1(1) 4.3

--- --- 0.030

Propiconazole 23 1(1) 4.3

--- --- 0.001

Tebuthiuron 23 1(1) 4.3

--- --- 0.003



### * Caffeine is not a pesticide compound, however it is included in this method.58 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 35. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at South Pacolet Reservoir, South Carolina

[Concentrations shown in micrograms per liter;

--- indicates value reported as les s than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method r eporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of

Pesticides by GC

- MS (NWQL method 2001)

Simazine 45 45 100 0.030 0.051 0.059

Atrazine 45 38(6) 84.4 0.005 0.008 0.010

Tebuthiuron 45 24(23) 53.3 0.003 0.008 0.008

Prometon 45 23(23) 51.1 0.002 0.005 0.013

Deethylatrazine 45 19(19) 42.2

--- 0.004 0.005

Meto lachlor 45 19(9) 42.2

--- 0.005 0.006

Azinphos

- methyl 43 7(7) 16.3

--- 0.054 0.144

Diazinon 45 5(5) 11.1

--- 0.001 0.003

Chlorpyrifos 45 4(4) 8.9

--- --- 0.002

p,p'

- DDE 45 3(3) 6.7

--- --- 0.002

Dacthal 45 2(2) 4.4

--- --- 0.001

Dieldrin 45 1(1) 2.2

--- - -- 0.002

Molinate 45 1(1) 2.2

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

1,4

- Naphthoquinone 44 1(1) 2.3

--- --- 0.002

1

- Naphthol 44 1(1) 2.3

--- --- 0.008

Hexazinone 44 1(1) 2.3

--- --- 0.007

M etalaxyl 44 1(1) 2.3

--- --- 0.011

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Deisopropylatrazine 44 20(20) 45.5

--- 0.011 0.016

Tebuthiuron 44 19(19) 43.2

--- 0.005 0.007

Desethyl desisopropylatrazine 44 16(16) 36.4

--- 0.007 0.047

Bentazon 44 12(12) 27.3

--- 0.007 0.013

2,4

- D 44 10(10) 22.7

--- 0.029 0.078

Atrazine 44 10(10) 22.7

--- 0.003 0.021

Diuron 44 7(7) 15.9

--- 0.007 0.068

Caffeine* 44 5(4) 11.4

--- 0.005 88.000

2

- Hydroxyatrazine 44 4(4) 9.1

--- --- 0.041

Me talaxyl 44 2(2) 4.5

--- --- 0.015

Benomyl 43 1(1) 2.3

--- --- 0.006

Dichlorprop 44 1(1) 2.3

--- --- 0.021

2,4

- D methyl ester 44 1(1) 2.3

--- --- 0.016

Carbaryl 44 1(1) 2.3

--- --- 0.006

Deethylatrazine 44 1(1) 2.3

--- --- 0.008

Dicamba 44 1(1) 2.3

--- - -- 0.049

Dinoseb 44 1(1) 2.3

--- --- 0.003

Imidacloprid 44 1(1) 2.3

--- --- 0.030

Metsulfuron

- methyl 44 1(1) 2.3

--- --- 0.168

Propiconazole 44 1(1) 2.3

--- --- 0.004

Siduron 44 1(1) 2.3

--- --- 0.007

Triclopyr 44 1(1) 2.3

--- --- 0.087



### * Caffeine is not a

pesticide compound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 59



### Table 36. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at South Pacolet Reservoir, South Carolina

[Concentrations shown in microgra ms per liter;

---

indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

ana lyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Simazine 16 16 100 0.041 0.047 0.047

Atrazine 16 13(3) 81.3 0.005 0.006 0.007

Tebuthiuron 16 9(9) 56.3 0.006 0.009 0.010

Deethylatrazine 16 8(8) 50.0

--- 0.003 0.004

M etolachlor 16 5(2) 31.3

--- 0.005 0.005

Prometon 16 3(3) 18.8

--- 0.004 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Desethyl desisopropylatrazine 15 9(9) 60.0 0.002 0.005 0.006

Tebuthiuron 15 6(6) 40.0

--- 0.005 0 .006

Caffeine* 15 3(3) 20.0

--- 0.015 0.016

Deisopropylatrazine 15 3(3) 20.0

--- 0.009 0.010

Bentazon 15 2(2) 13.3

--- 0.002 0.005

2

- Hydroxyatrazine 15 1(1) 6.7

--- --- 0.009

Atrazine 15 1(1) 6.7

--- --- 0.002

Bendiocarb 15 1(1) 6.7

--- --- 0.001

Diuron 1 5 1(1) 6.7

--- --- 0.011

Metsulfuron

- methyl 15 1(1) 6.7

--- --- 0.003

Terbacil 15 1(1) 6.7

--- --- 0.021



### * Caffeine is not a pesticide compound, however it is included in this method.60 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 37. Statistical summary of pesticides and degradates detected in water sa mples from the finished

water monitoring site at Spartanburg Waterworks, South Carolina

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method perf ormance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Simazine 27 27 100 0.027 0.039 0.051

Atrazine 27 23(8) 85.2 0.004 0.007 0.008

Deethylatrazine 27 14(14) 51.9 0.001 0.003 0.004

Tebuthiuron 27 11(11) 40.7

--- 0.006 0.008

Metolachlor 27 9(3) 33.3

--- 0.005 0.005

Prometon 27 7(7) 25.9

--- 0.003 0.004

Azinphos

- methyl 25 5(5) 20.0

--- 0.038 0.114

p,p'

- DDE 27 2(2) 7.4

--- --- 0.002

Pronamide 27 1(1) 3.7

--- --- 0.003

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

2

- [2

- Ethyl

- 6

- methylphenyl)amino]

-

1

- propanol 26 1(1) 3.8

--- --- 0.007

Bifenthrin 26 1(1) 3.8

--- --- 0.002

Metalaxyl 26 1(1) 3.8

--- --- 0.009

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Deisopropylatrazine 26 9(9) 34.6

--- 0.010 0.013

Desethyl desisopropylatrazine 26 8(8) 30.8

--- 0.018 0.036

Tebuthiuron 26 8(8) 30. 8

--- 0.004 0.005

Bentazon 26 4(4) 15.4

--- 0.005 0.010

Atrazine 26 3(3) 11.5

--- 0.002 0.003

2,4

- D 26 2(2) 7.7

--- --- 0.021

2

- Hydroxyatrazine 26 2(2) 7.7

--- --- 0.007

Bromacil 26 1(1) 3.8

--- --- 0.013

Dicamba 26 1(1) 3.8

--- --- 0.016

Diuron 26 1(1) 3 .8

--- --- 0.008

Metalaxyl 26 1(1) 3.8

--- --- 0.004

Oryzalin 26 1(1) 3.8

--- --- 0.037Summary of Results from a Pilot Monitoring Program 61



### Table 38. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Lake Mitchell, South Dakota

[Concentration s shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide c oncentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value pe rcentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 21 21 100 1.320 2.310 2.530

Cyanazine 21 21(1) 100 0.025 0.035 0.038

Deethylatrazine 21 21(21) 100 0.273 0.363 0.444

Metolachlor 21 21 100 0.025 0.061 0.079

Prometon 21 21(21) 100 0.010 0.012 0.015

Acetochlor 21 19 90.5 0.030 0.249 0.334

Simazine 21 15(2) 71.4 0.007 0.014 0.016

EPTC 21 10 47.6

--- 0.030 0.036

Alachlor 21 3 14.3

--- 0.011 0.013

Tebuthiuron 21 2(2) 9.5

--- --- 0.004

Trifluralin 21 2(2) 9.5

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

4

- (Hydroxymethyl)pendimethalin 21 1(1) 4.8

--- --- 0.045

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 21 21(21) 100 0.725 1.350 1.664

Atrazine 21 21(12) 100 1.098 1.745 2.508

Deethylatrazine 21 21(10) 100 0.199 0.259 0.302

Deisopropylatrazine 21 21(14) 100 0.073 0.108 0.160

2,4

- D 21 17(6) 81.0 0.082 0.102 0.414

Desethyl desisopropylatr azine 21 14(11) 66.7 0.027 0.062 0.074

Picloram 21 8 38.1

--- 0.259 0.360

Nicosulfuron 21 7(7) 33.3

--- 0.086 0.139

2,4

- D methyl ester 21 6(6) 28.6

--- 0.011 0.054

Dicamba 21 4(3) 19.0

--- 0.030 0.104

Metalaxyl 21 4(4) 19.0

--- 0.007 0.008

Imazethapyr 19 2(2) 10.5

--- 0.071 0.133

Bentazon 21 1(1) 4.8

--- --- 0.015

Caffeine* 21 1(1) 4.8

--- --- 0.019

Chlorimuron

- ethyl 21 1(1) 4.8

--- --- 0.021

Diuron 21 1(1) 4.8

--- --- 0.010

Oryzalin 21 1 4.8

--- --- 0.127

Tebuthiuron 21 1(1) 4.8

--- --- 0.008



### * Caffeine i s not a pesticide compound, however it is included in this method.62 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 39. Statistical summary of pesticides and degradates detected in water samples from the reservoir

outflow monitoring site at Lake Mitchell, South Dakota

[Concentrations shown in micrograms pe r liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

conc entrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Acetochlor 9 9 100 0.102 0.395 0.395

Atrazine 9 9 100 1.720 2.660 2.660

Cyanazine 9 9 100 0.032 0.065 0.065

Deethylatrazine 9 9(9) 100 0.151 0.395 0.395

Metolachlor 9 9 100 0.039 0.083 0.083

Prometon 9 9(9) 100 0.010 0.018 0.018

Simazine 9 9 100 0.013 0.016 0.016

Alachlor 9 4 44.4

--- 0.017 0.017

EPTC 9 4 44.4

--- 0.038 0.038

Trifluralin 9 2(2) 22.2

--- 0.003 0.003

Carbaryl 9 1(1) 11.1

--- 0.001 0.001

Tebuthiuron 9 1(1) 11. 1

--- 0.006 0.006

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

2,5

- Dichloroaniline 9 1(1) 11.1

--- 0.005 0.005

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 9 9(9) 100 0.999 1.913 1.913

Atrazine 9 9(8) 100 1.466 1.821 1.821

Deethylatrazine 9 9(3) 100 0.129 0.237 0.237

Deisopropylatrazine 9 9(6) 100 0.058 0.089 0.089

2,4

- D 9 8(3) 88.9 0.095 0.702 0.702

Desethyl desisopropylatrazine 9 7(7) 77.8 0.024 0.058 0. 058

2,4

- D methyl ester 9 4(4) 44.4

--- 0.077 0.077

Nicosulfuron 9 3(3) 33.3

--- 0.128 0.128

Imazethapyr 8 1(1) 12.5

--- 0.027 0.027

Chlorimuron

- ethyl 9 1(1) 11.1

--- 0.023 0.023

Diuron 9 1(1) 11.1

--- 0.011 0.011

Metalaxyl 9 1(1) 11.1

--- 0.007 0.007Summary of Results from a Pilot Monitoring Program 63



### Table 40. St

atistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at Mitchell Water Department, South Dakota

[Concentrations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 22 22 100 1.165 2.110 2.470

Cyanazine 22 22(1) 100 0.024 0.038 0.051

Deethylatrazine 22 22(22) 100 0.244 0.328 0.352

Metolachlor 22 22 100 0.024 0.058 0.072

Prometon 22 22(22) 100 0.010 0.013 0.017

Acetochlor 22 21 95.5 0.027 0.289 0.395

Simazine 22 15(2) 68.2 0.006 0.012 0.014

EPTC 22 11 50.0 0.002 0.019 0.029

Alachlor 22 4 18.2

--- 0.009 0.011

Tebuthiuron 22 3(3) 13.6

--- 0.002 0.004

Trifluralin 22 2(2) 9.1

--- --- 0.002

Analysis of Moderate

- Use Pesticides and Degradates by GC

- MS (NWQL provisional method 9002)

2,5

- Dichloroaniline 21 1 4.8

--- --- 0.009

4

- (Hydroxymethyl)pendimethalin 21 1(1) 4.8

--- --- 0.029

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 22 22(22) 100 0.765 1.344 1.785

Atrazine 22 22(11) 100 1.032 1.728 1.944

Deethylatrazine 22 22(11) 100 0.172 0.206 0.267

Deisopropylatrazine 22 22(20) 100 0.055 0.071 0.141

2,4

- D 22 19(11) 86.4 0.070 0.337 0.634

2,4

- D methyl ester 22 13(12) 59.1 0.008 0.055 0.136

Desethyl desisopropylatrazine 22 13(12) 59.1 0.018 0.054 0.069

Picloram 22 11(1) 50.0 0.047 0.276 0.389

Nicosulfuron 22 8(8) 36.4

--- 0.074 0.093

Dicamba 22 4(3) 18.2

--- 0.046 0.147

Chlorimuron

- ethyl 22 2(2) 9.1

--- --- 0.026

Diuron 22 2(2) 9.1

--- --- 0.029

Metal axyl 22 2(2) 9.1

--- --- 0.010

Bentazon 22 1(1) 4.5

--- --- 0.015

Oryzalin 22 1 4.5

--- --- 0.09564 Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: 

### Table 41. Statistical summary of pesticides and degradates detected in water samples from the water

supply intake monitoring site at Lake Waxahachie, Texas

[Concentr ations shown in micrograms per liter;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pestic ide concentrations

-- for

concentrations quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, valu e percentile value

analyses estimates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 22 22 100 0.531 0.577 0.612

Deethylatrazine 22 22(22) 100 0.104 0.128 0.137

Metolachlor 22 22 100 0.045 0.066 0.078

Simazine 22 18 81. 8 0.016 0.018 0.021

Tebuthiuron 22 10(10) 45.5

--- 0.006 0.008

Diazinon 22 6(5) 27.3

--- 0.004 0.004

Prometon 22 6(6) 27.3

--- 0.006 0.008

p,p'

- DDE 22 6(6) 27.3

--- 0.002 0.003

Alachlor 22 1(1) 4.5

--- --- 0.004

Analysis of Moderate

- Use Pesticides and Deg radates by GC

- MS (NWQL provisional method 9002)

Prometryn 22 17(9) 77.3 0.006 0.010 0.013

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

Atrazine 22 22(5) 100 0.359 0.533 0.741

Deethylatrazine 22 22(22) 100 0.052 0.073 0 .098

2

- Hydroxyatrazine 22 19(19) 86.4 0.425 0.549 0.714

Deisopropylatrazine 22 19(19) 86.4 0.010 0.024 0.038

Desethyl desisopropylatrazine 22 17(17) 77.3 0.007 0.014 0.016

2,4

- D 22 11(10) 50.0 0.009 0.074 0.079

Caffeine* 22 5(5) 22.7

--- 0.027 0.038

Tebuth iuron 22 3(3) 13.6

--- 0.002 0.005

2,4

- D methyl ester 22 2(2) 9.1

--- --- 0.030

Bentazon 22 2(2) 9.1

--- --- 0.006

Diuron 22 2(2) 9.1

--- --- 0.008

Diphenamid 22 1(1) 4.5

--- --- 0.002

Metalaxyl 22 1(1) 4.5

--- --- 0.003



### * Caffeine is not a pesticide comp ound, however it is included in this method.Summary of Results from a Pilot Monitoring Program 65



### Table 42. Statistical summary of pesticides and degradates detected in water samples from the finished

water monitoring site at City of Waxahachie Water Treatment Plant, Texas

[Concentrations shown in micrograms per lit er;

--- indicates value reported as less than the method reporting level; GC

- MS, gas chromatography

– mass spectrometry; HPLC

- MS, high performance liquid chromatography

– mass spectrometry; (),qualified estimates of pesticide concentrations

-- for

concentra tions quantified less than the method reporting level and for compounds with low and variable recoveries based on method performance]

Compound Number Detections Detection Median 90 th Maximum

of (qualified frequency, value percentile value

analyses esti mates) in percent value

Analysis of Pesticides by GC

- MS (NWQL method 2001)

Atrazine 9 9 100 0.515 0.589 0.589

Deethylatrazine 9 9(9) 100 0.111 0.134 0.134

Metolachlor 9 9 100 0.039 0.050 0.050

Simazine 9 8 88.9 0.017 0.020 0.020

Tebuthiuron 9 5(5) 55.6 0.005 0.008 0.008

Prometon 9 3(3) 33.3

--- 0.008 0.008

Analysis of Pesticides and Degradates by HPLC

- MS (NWQL provisional method 9060)

2

- Hydroxyatrazine 8 8(8) 100 0.480 0.728 0.728

Atrazine 8 8(1) 100 0.389 0.717 0.717

Deethylatrazine 8 8(8) 100 0.066 0.089 0.089

Deisopropylatrazine 8 8(8) 100 0.014 0.020 0.020

Desethyl desisopropylatrazine 8 6(6) 75.0 0.010 0.013 0.013

2,4

- D 8 4(4) 50.0 0.014 0.060 0.060

Tebuthiuron 8 1(1) 12.5

--- 0.003 0.003