Anthropogenic Organic Compounds 

in Source and Finished Water from 

Community Water System Wells in 

Western and Central Connecticut, 

2002–2004

By Thomas J. Trombley, Craig J. Brown, and Gregory C. Delzer

National Water-Quality Assessment Program 

Source Water-Quality Assessments

Scientific Investigations Report 2007–5171

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation:

Trombley, T.J., Brown, C.J., and Delzer, G.C., 2007, Anthropogenic organic compounds in source and finished water 

from community water system wells in western and central Connecticut, 2002–2004: U.S. Geological Survey 

Scientific Investigations Report 2007–5171, 38 p.
iii

Foreword

The U.S. Geological Survey (USGS) is committed to providing the Nation with accurate and 

timely scientific information that helps enhance and protect the overall quality of life and that 

facilitates effective management of water, biological, energy, and mineral resources (http://

www.usgs.gov/). Information on the quality of the Nation’s water resources is critical to assuring the long-term availability of water that is safe for drinking and recreation and suitable for 

industry, irrigation, and habitat for fish and wildlife. Population growth and increasing demands 

for multiple water uses make water availability, now measured in terms of quantity and quality, 

even more essential to the long-term sustainability of our communities and ecosystems.

The USGS implemented the National Water-Quality Assessment (NAWQA) Program in 1991 to 

support national, regional, and local information needs and decisions related to water-quality 

management and policy (http://water.usgs.gov/nawqa). Shaped by and coordinated with 

ongoing efforts of other Federal, State, and local agencies, the NAWQA Program is designed 

to answer: What is the condition of our Nation’s streams and ground water? How are the 

conditions changing over time? How do natural features and human activities affect the quality 

of streams and ground water, and where are those effects most pronounced? By combining 

information on water chemistry, physical characteristics, stream habitat, and aquatic life, the 

NAWQA Program aims to provide science-based insights for current and emerging water issues 

and priorities.

From 1991–2001, the NAWQA Program completed interdisciplinary assessments in 51 of the 

Nation’s major river basins and aquifer systems, referred to as Study Units (http://water.usgs.

gov/ nawqa/studyu.html). Baseline conditions were established for comparison to future assessments, and long-term monitoring was initiated in many of the basins. During the next decade, 

42 of the 51 Study Units will be reassessed so that 10 years of comparable monitoring data 

will be available to determine trends at many of the Nation’s streams and aquifers. The next 

10 years of study also will fill in critical gaps in characterizing water-quality conditions, enhance 

understanding of factors that affect water quality, and establish links between sources of contaminants, the transport of those contaminants through the hydrologic system, and the potential 

effects of contaminants on humans and aquatic ecosystems.

The USGS aims to disseminate credible, timely, and relevant science information to inform practical and effective water-resource management and strategies that protect and restore water 

quality. We hope this NAWQA publication will provide you with insights and information to 

meet your needs, and will foster increased citizen awareness and involvement in the protection 

and restoration of our Nation’s waters.

The USGS recognizes that a national assessment by a single program cannot address all waterresource issues of interest. External coordination at all levels is critical for a fully integrated 

understanding of watersheds and for cost-effective management, regulation, and conservation 

of our Nation’s water resources. The NAWQA Program, therefore, depends on advice and information from other agencies—Federal, State, interstate, Tribal, and local—as well as nongovernmental organizations, industry, academia, and other stakeholder groups. Your assistance and 

suggestions are greatly appreciated.

Robert M. Hirsch

Associate Director for Water

v

Contents

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

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

Purpose and Scope ..............................................................................................................................4

Ground-Water Withdrawals and Land Use in the Study Area......................................................4

Site Selection, Methods, and Human-Health Benchmarks....................................................................4

Site Selection and Methods................................................................................................................4

Human-Health Benchmarks................................................................................................................6

Consumer Confidence Reports and Source Water-Quality Assessments..................................7

Anthropogenic Organic Compounds in Source Water............................................................................7

Volatile Organic Compounds...............................................................................................................7

Pesticides.............................................................................................................................................10

Other Anthropogenic Organic Compounds ....................................................................................10

Anthropogenic Organic Compounds in Source and Associated Finished Water.............................10

Volatile Organic Compounds.............................................................................................................10

Pesticides.............................................................................................................................................14

Other Anthropogenic Organic Compounds ....................................................................................14

Summary........................................................................................................................................................17

Acknowledgments.......................................................................................................................................17

References Cited..........................................................................................................................................17

Glossary.........................................................................................................................................................21

Appendix 1. Concentration and Benchmark Quotient Values for Detected Anthropogenic 

Organic Compounds in Samples of Source Water and Associated Finished Water, 

Connecticut SWQA Study.............................................................................................................23

Figures

1–3. Maps showing—

1. Location of National Water-Quality Assessment (NAWQA) study units and 

Ground-Water Source Water-Quality Assessment (SWQA) study areas..................2

2. Glacial stratified aquifer in western and central Connecticut and location of 

community water system wells sampled in Phase I (source water) and 

Phase II (source and finished water) of the Connecticut source waterquality assessment..............................................................................................................3

3. Land use in western and central Connecticut and location of community 

water system wells sampled in Phase I (source water) and Phase II (source 

and finished water) of the Connecticut source water-quality assessment...............5
vi

4–7. Graphs showing—

4. Concentration, number of detections, and benchmark quotient values for 

(A) volatile organic compounds, (B) pesticides, and (C) other anthropogenic 

organic compounds detected in 15 community water system wells sampled in 

Phase I (source water) of the Connecticut source water-quality assessment ........9

5. (A) Concentrations and number of detections and (B) benchmark quotient 

values for volatile organic compounds detected in 10 community water 

system wells sampled in Phase II (source and finished water) of the 

Connecticut source water-quality assessment............................................................11

6. (A) Concentrations and number of detections and (B) benchmark quotient 

values for pesticides detected in 10 community water system wells sampled in 

Phase II (source and finished water) of the Connecticut source water-quality 

assessment.........................................................................................................................15

7. (A) Concentrations and number of detections and (B) benchmark quotient 

values for other anthropogenic organic compounds detected in 10 community 

water system wells sampled in Phase II (source and finished water) of the 

Connecticut source water-quality assessment............................................................16

Tables

1. Detection frequency, maximum concentration, and maximum benchmark quotient 

value for anthropogenic organic compounds detected in 15 community water 

system wells sampled in Phase I (source water) of the Connecticut source waterquality assessment.......................................................................................................................8

2. Detection frequency, maximum concentration, and maximum benchmark quotient 

value for anthropogenic organic compounds detected in 10 community water 

system wells sampled in Phase II (source and finished water) of the Connecticut 

source water-quality assessment............................................................................................12
vii

Conversion Factors, Abbreviations, Datums, and Acronyms

Distances in kilometers may be converted to miles by multiplying by 0.6214.

Concentrations of chemical constituents are given in micrograms per liter (μg/L).

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

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

ABBREVIATIONS

< less than

> greater than

AOC Anthropogenic organic compound

BQ Benchmark quotient

BQmax Ratio of the maximum concentration of a contaminant to a drinking-water benchmark

CASRN Chemical Abstracts Service Registry Number

CCR Consumer confidence report

CWS Community water system

E Estimated concentration

DBP Disinfection by-product

DEET N,N,-diethy-meta-toluamide

HBSL Health-Based Screening Level

GIS Geographic information system

MCL Maximum contaminant level

MRL Minimum reporting level

OAOC Other anthropogenic organic compound

MTBE Methyl tert-butyl ether

NAWQA National Water-Quality Assessment

NWQL National Water Quality Laboratory

PCE Perchloroethene

SWQA Source Water-Quality Assessment

TCE Trichloroethene

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

VOC Volatile organic compound

Abstract

A water-quality assessment by the U.S. Geological 

Survey (USGS) determined the occurrence of anthropogenic 

(manmade) organic compounds (AOCs) in water from 15 

community water system (CWS) wells and associated finished 

drinking water. The study, which focused on water from the 

unconfined glacial stratified aquifer in western and central 

Connecticut, was conducted as part of the USGS National 

Water-Quality Assessment Program (NAWQA) Source WaterQuality Assessment (SWQA) project and included analysis of 

water samples for 88 volatile organic compounds (VOCs), 

120 pesticides, and 50 other anthropogenic organic 

compounds (OAOCs).

During Phase I of the study, 25 AOCs were detected 

(12 VOCs, 10 pesticides, and 3 OAOCs) in source-water 

samples collected from 15 CWS wells sampled once from 

October 2002 to May 2003. Although concentrations generally 

were low (less than 1 microgram per liter), four compounds 

were detected at higher concentrations in ground water from 

four wells. The most frequently occurring AOCs were detected 

in more than half of the samples and included chloroform 

(87 percent), methyl tert-butyl ether (MTBE, 80 percent), 

1,1,1-trichloroethane (67 percent), atrazine (60 percent), 

deethylatrazine (60 percent), perchloroethene (PCE, 53 percent), and simazine (53 percent). Trichloroethene (TCE) 

was detected in 47 percent of samples. Samples generally 

contained a mixture of compounds ranging from 2 to 19 

detected compounds, with an average of 8 detected compounds per sample. 

During Phase II of the study, 42 AOCs were detected in 

source-water samples collected from 10 resampled CWS wells 

or their associated finished water. Trihalomethanes accounted 

for most of the VOCs detections with all concentrations less 

than 1 microgram per liter. Chloroform, the most frequently 

detected VOC, was found in all source-water and all 

finished-water samples. As with the Phase I samples, other 

frequently detected VOCs included MTBE, and the solvents 

1,1,1-trichloroethane, PCE, and TCE. Triazine herbicides 

and their degradation products accounted for most of the 

detected pesticides.

Introduction

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

National Water-Quality Assessment (NAWQA) Program 

to (1) provide a nationally consistent description of current 

water-quality conditions for more than 50 of the largest and 

most important river basins and aquifers across the Nation; 

(2) define long-term trends in water quality; and (3) identify, 

describe, and explain, as much as possible, the major factors 

that affect observed water-quality conditions and trends. This 

information, which is obtained on a continuing basis, is made 

available to water managers, policy makers, and the public to 

help address and prioritize the multitude of issues related to 

managing and protecting our water resources.

Beginning in 2001, the NAWQA Program began its 

second decade of intensive assessment activities by returning 

to 42 of the original river basins and aquifers studied during 

the first decade to build upon the initial assessments of 

water-quality conditions and establish links between sources, 

transport, and the potential effects of contaminants on humans 

and aquatic ecosystems. This is accomplished through a 

variety of new, focused study components within the NAWQA 

Program. One such new assessment activity focuses on 

characterizing the quality of rivers and aquifers used as a 

source of supply to community water systems (CWSs)1 in 

many of the NAWQA study basins (fig. 1). These activities are 

called Source Water-Quality Assessments (SWQAs) and are 

intended to complement drinking-water monitoring required 

by federal, state, and local programs, which focus primarily 

on post-treatment compliance monitoring. Through SWQAs, 

NAWQA is increasing its emphasis on characterizing rivers 

and aquifers that are major sources of drinking water and will 

continue to collaborate with other agencies and organizations 

involved with supplying and managing drinking water. 

Currently (2007), 15 ground-water SWQAs are in various 

stages of completion by NAWQA. This report focuses on 

a ground-water SWQA in the unconfined glacial stratified 

aquifer (fig. 2) in western and central Connecticut.

1

 Words in bold are defined in the Glossary at the back of this report.

Anthropogenic Organic Compounds in Source and 

Finished Water from Community Water System Wells in 

Western and Central Connecticut, 2002–2004

By Thomas J. Trombley, Craig J. Brown, and Gregory C. Delzer
2 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Sampling for ground-water SWQAs consists of two 

phases. Phase I focuses on determining the occurrence of 

258 anthropogenic organic compounds (AOCs) (Metz and 

others, 2006) in the source water of selected CWS wells in 

the NAWQA study units. Phase II focuses on those AOCs 

detected most frequently during Phase I of sampling and 

evaluates their detection frequencies and concentrations in 

source water and the associated finished water. As used in 

this study, source water is the raw (ambient) water collected 

at the supply well prior to water treatment, finished water is 

the source water or blended water that is treated and ready to 

be delivered to consumers, and blended water is a mixture 

of water from several ground-water sources. Finished water 

may be composed of water from multiple CWS wells (blended 

water) or it may be composed only of water from one CWS 

well and treated at (or near) the well (non-blended). Blended 

water, by definition, could include a mixture of ground water 

and surface water; however, for the purposes of this study (as 

well as other ground-water SWQAs) blended water refers only 

to blended ground water.

AOCs monitored as part of SWQAs include volatile 

organic compounds (VOCs), pesticides, and other anthropogenic organic compounds (OAOCs). VOCs are a subset of 

organic chemicals that have been produced and used in a variety of commercial, industrial, and household applications for 

many decades and are a major component or additive to gasoline, paints, varnishes, glues, dyes, and plastics (Zogorski and 

others, 2006). Pesticides are used extensively throughout the 

United States to increase crop yields; enhance the aesthetics 

of lawns, gardens, golf courses, and recreational areas; and to 

protect the safety of the public from insect-associated diseases. 

The widespread use of pesticides over the past several decades 

has led to their frequent detection in ground water (Barbash 

and Resek, 1996; Barbash and others, 1999). OAOCs represent a group of compounds that are present in a wide range of 

products commonly used in homes, industry, and agriculture, 

including personal-care and domestic-use products, plant- or 

animal-derived biochemicals, and fumigants. Little is known 

about the environmental occurrence, transport, and ultimate 

fate of OAOCs after their intended use; however, it is known 

Figure 1. Location of National Water-Quality Assessment (NAWQA) study units and Ground-Water Source Water-Quality 

Assessment (SWQA) study areas. 

NAWQA Study Units—Scheduled

 to begin in fiscal year:

2001

2004

2007

Ground-Water Source Water-Quality

 Assessment location 

Connecticut

SWQA Study Area

0 200 400 MILES

0 200 400 KILOMETERS

Base modifed from U.S. Geological Survey

digital data, 1:2,000,000, 1990

Albers Equal-Area Projection

North American Datum of 1983

EXPLANATION
Introduction 3

Figure 2. Glacial stratified aquifer in western and central Connecticut and location of community water system wells sampled 

in Phase I (source water) and Phase II (source and finished water) of the Connecticut source water-quality assessment. 

73°20' 73° 72°40'

41°40'

41°20'

41°

15

14

13

12

11

10

9

8

6

5

4

3

2

1

7

Woodbury

Southington

Long Island Sound

15

14

13

12

11

10

9

8

6

5

4

3

2

1

7

Towns

0 5 10 MILES

0 5 10 15 KILOMETERS

Glacial stratified deposits from USGS digital data, 1:1,000,000

DDS-38, 1998

Base from U.S. Geological Survey, 1:24,000, 1969 to 1984

Connecticut State Plane projection

EXPLANATION

WELLS

GLACIAL DEPOSITS

Coarse-grained stratified deposits

Fine-grained stratified deposits

Finished-water sampling site

Source-water sampling site
4 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

that these compounds commonly are released directly to the 

environment after passing through wastewater treatment plants 

or domestic septic systems that often are not designed to 

remove these compounds from the effluent (Herberer, 2002; 

and Ternes and others, 2002). Until recently, few analytical 

methods were capable of detecting these compounds at the low 

concentrations that might be expected in the environment.

Data from most water-quality studies conducted by the 

USGS cannot be compared directly to data on the quality of 

source water from CWSs because of construction and pumping differences in the type of well sampled (such as monitoring and domestic wells). Consequently, a need exists to 

qualitatively determine if the results of these other studies are 

representative of the quality of source water used by large and 

very large CWSs. Similarly, because the application of various 

treatment technologies alters the chemistry of source water 

to meet federal and state drinking-water requirements, a need 

exists to better understand how representative source water is 

of finished water prior to distribution. Linking these types of 

studies is important, especially considering the documented 

occurrence of AOCs in finished water at concentrations similar 

to those found in source water (Loraine and Pettigrove, 2006; 

Stackelberg and others, 2004) and in simulated drinking-water 

treatment processes (Westerhoff and others, 2005). Thus, data 

obtained through SWQAs characterize not only the quality of 

source water and finished water of some of the larger CWSs 

prior to distribution, but also begin to provide a mechanism 

to bring results obtained from other studies into context with 

water used for human consumption. 

Purpose and Scope

This report describes the occurrence of 258 AOCs in 

ground water sampled from 15 CWS wells in western and 

central Connecticut during 2002–2004. Additionally, the 

report describes the detection frequency and concentrations of 

selected AOCs in samples from 10 of the 15 CWS wells and 

in the associated finished water. Concentrations are compared 

to U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs) and USGS Health-Based 

Screening Levels (HBSLs) to evaluate the potential relevance 

of the findings to human health.

Ground-Water Withdrawals and Land Use 

in the Study Area

Although the major cities in Connecticut rely on surface 

water for freshwater withdrawals for drinking-water supply, 

many surrounding towns rely mostly on ground water. Urban 

populations typically are concentrated in towns that overlie 

glacial aquifers in valleys. Of the 2.7 million people served by 

public water-supply systems in Connecticut, about 11 percent 

have publicly supplied (community supply) ground water 

as their source of drinking water. In addition, about 700,000 

people in Connecticut drink water from domestic wells, and 

about 190,000 people drink ground water from non-community systems, such as schools and businesses (Starn and Stone, 

2005). Glacial aquifers supply about 90 percent of public 

ground-water supply. Nearly all domestic wells obtain water 

from fractured bedrock. 

Towns in the study area (fig. 2) have populations ranging 

from 9,200 in Woodbury to about 40,000 in Southington 

(U.S. Census Bureau, 2002). Since 1960, areas near the sampled wells have changed from primarily undeveloped or agricultural lands to residential, commercial, and industrial areas. 

Residential and commercial development tends to be more 

concentrated in the valleys, which overlie the glacial aquifers. 

Agricultural lands in the study area are limited; located mostly 

on flood plains, they produce silage corn, hay, and ornamental 

and bedding plants (fig. 3).

Site Selection, Methods, and 

Human-Health Benchmarks

This section describes the number of wells sampled, the 

selection process, and methods for sample collection and analyses. Regulated and non-regulated human-health benchmarks 

also are described, and a description of how water-quality 

results are interpreted in a human-health context is provided.

Site Selection and Methods

Fifteen wells (fig. 2) completed in the unconfined glacial 

stratified aquifer in western and central Connecticut were 

selected for sampling. Only CWS wells that are among the 

highest producing and deemed not to be under the direct 

influence of surface water were sampled. Sampled wells 

were at least 1 km apart to ensure that the contributing areas 

for the wells do not overlap. The “Surface Water Treatment 

Rule,” enforced by the state of Connecticut, requires that all 

CWS wells satisfy criteria that indicate they are not under the 

direct influence of surface water. These criteria include source 

construction, separation distance, water quality, and history 

of disease outbreak. If a well fails to meet any of the criteria, 

the utility must perform a demonstration study, replace the 

source, reconstruct the source, or install treatment. Wells were 

sampled once from October 2002 through May 2003, and 

samples were analyzed for 88 VOCs, 120 pesticides, and 

50 OAOCs (Metz and others, 2006). 

During Phase II of the study, 10 of the 15 wells were 

resampled once in June or July 2004 based on the occurrence 

of AOCs detected most frequently in Phase I. Samples of both 

source water and associated finished water from 8 of the 

10 wells were analyzed for VOCs, depending on the specific 

compounds; samples from 6 to 10 wells were analyzed for 

pesticides and OAOCs. All ground-water samples were 

collected using established USGS protocols (Koterba and 
Site Selection, Methods, and Human-Health Benchmarks 5

Figure 3. Land use in western and central Connecticut and location of community water system wells sampled in Phase I 

(source water) and Phase II (source and finished water) of the Connecticut source water-quality assessment. 

73°20' 73° 72°40'

41°40'

41°20'

41°

15

14

13

12

11

10

9

8

6

5

4

3

2

1

7

Woodbury

Southington

Long Island Sound

15

14

13

12

11

10

9

8

6

5

4

3

2

1

7

Towns

0 5 10 MILES

0 5 10 15 KILOMETERS

Land cover from LANDSAT Thematic Mapper (TM) satellite

imagery based, land-cover classification, 2002, University of Connecticut

Base from U.S. Geological Survey, 1:24,000, 1969 to 1984

Connecticut State Plane projection

EXPLANATION

WELLS

LAND USE - LAND COVER

Developed

Grasslands and agriculture

Forest

Water

Wetland

Other

Finished-water sampling site

Source-water sampling site
6 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

others, 1995). Finished-water samples were collected after 

treatment and prior to the entry to transport pipelines. 

Samples were sent to the USGS National Water Quality 

Laboratory (NWQL) in Denver, Colorado, for analysis. For 

documentation pertaining to the analytical methods, see 

Zaugg and others (1995), Lindley and others (1996), Connor 

and others (1998), Furlong and others (2001), Sandstrom 

and others (2001), Zaugg and others (2002), and Madsen and 

others (2003). Some compounds were detected in 10 percent 

or more of NWQL laboratory set blanks. The contamination 

for these constituents can be characterized as random, as no 

systematic error was identified that affected sample results. 

Field and laboratory quality-control data suggest that, 

although a specific source cannot be identified, the quality of 

the environmental data for phenol is unknown; therefore, all 

phenol concentrations in samples were censored and removed 

from the data set. Similarly, N,N-diethyl-meta-toluamide 

(DEET) was detected at similar or greater detection frequency 

in blank samples than in environmental samples. Because 

of the uncertainty in the quality of DEET concentrations in 

environmental samples, all DEET data were censored and not 

used in any subsequent analyses.

In Phase II, a dechlorination reagent and, for some 

schedules, a pH buffer, were added to finished-water samples 

to reduce the degradation of organic compounds by converting 

free chlorine to chloride. A preliminary study was conducted 

by the NWQL to determine if SWQAs could begin using 

these reagents without any negative impact on the analytical 

performance. Results indicated that recoveries were not 

affected by the addition of these reagents (Mark Sandstrom, 

U.S. Geological Survey National Water Quality Laboratory, 

written commun., 2007); however, it has been established 

that the dechlorination reagents added to finished-water 

samples (specifically the pH buffer—Trizma) systematically 

contaminate samples with benzophenone, isophorone, and 

para-nonylphenol (Office of Water Quality Water-Quality 

Information Note 2007.04). Although the pH buffer only 

contaminated the finished-water data, all concentrations 

of benzophenone, isophorone, and para-nonylphenol were 

removed from the data set.

Human-Health Benchmarks

The USGS began an interagency pilot effort in 1998 

to communicate the significance of water-quality findings 

of the NAWQA Program in a human-health context. 

Historically, the USGS has assessed water-quality conditions 

by comparing water concentration data with human-health 

benchmarks, such as established federal or state drinkingwater standards and drinking-water guidelines. The 

drinking-water standards for regulated compounds are 

called maximum contaminant levels (MCLs), which protect 

drinking-water quality by limiting the concentration of specific 

compounds delivered to any user of a public water system 

that can adversely affect public health (U.S. Environmental 

Protection Agency, 2002). Drinking-water standards and 

guidelines do not exist, however, for nearly one-half of the 

compounds analyzed by the NAWQA Program and other 

USGS studies. Health-Based Screening Levels (HBSLs) are 

estimates of benchmark concentrations of contaminants in 

water that may be of potential human-health concern and are 

consistent with USEPA Office of Water methodologies for 

setting guidelines for nonenforceable drinking-water values. 

In order to provide a more complete understanding of the 

significance of water-quality data collected, existing federal 

drinking-water standards and guidelines are supplemented by 

HBSL concentrations or ranges calculated for unregulated 

compounds (compounds without federal drinking-water 

standards) monitored by the NAWQA Program using an 

approach that was developed collaboratively by the USGS, 

USEPA, New Jersey Department of Environmental Protection, 

and Oregon Health & Science University (Toccalino and 

others, 2003, 2004).

HBSLs are not regulatory standards, are not enforceable, 

and water systems are not required to monitor for any 

unregulated compounds for which HBSLs have been 

developed. HBSLs can be used as thresholds against which 

contaminant concentrations in water can be compared to 

evaluate water-quality data in a human-health context. HBSLs 

can be used as planning tools to help prioritize contaminants 

that may merit further study or monitoring and to provide an 

early indication of contaminant concentrations of potential 

human-health concern in water resources (Toccalino and 

others, 2005). Descriptions of the human-health benchmarks 

that were used in this study can be seen in Metz and others 

(2006, appendix 4). 

To aid in evaluating water-quality data in the context of 

human health, benchmark quotient (BQ) values were calculated. A BQ value is the ratio of a measured concentration of 

a detected compound to its MCL (for a regulated compound) 

or HBSL (for an unregulated compound). For this study, the 

maximum concentration detected for each compound was 

used to calculate this ratio, called BQmax. A BQmax value 

greater than or equal to 1.0 was used to identify concentrations of potential human-health concern (hereafter referred 

to as concentrations of potential concern). A BQmax threshold 

value greater than or equal to 0.1 was used to identify compounds that may warrant inclusion in a low-concentration, 

trends-monitoring program; frequently occurring compounds 

(in this report, frequently occurring indicates an occurrence of 

an AOC in 10 percent or more of samples) also may warrant 

inclusion in such a monitoring program. Such monitoring may 

provide an early indication of contaminant levels that approach 

human-health benchmarks, and consequently, concentrations 

of potential concern.
Anthropogenic Organic Compounds in Source Water 7

Anthropogenic Organic Compounds in 

Source Water

A total of 25 of the 258 individual AOCs were 

detected (12 VOCs, 10 pesticides, and 3 OAOCs) in samples 

collected from 15 CWS wells sampled from October 2002 

to May 2003 (table 1). The most frequently occurring AOCs 

were detected in more than half of the 15 source-water samples and included chloroform (87 percent of samples), methyl 

tert-butyl ether (MTBE, 80 percent), 1,1,1-trichloroethane 

(67 percent), atrazine (60 percent), deethylatrazine (60 percent), perchloroethene (PCE, 53 percent), and simazine 

(53 percent). Samples generally contained a mixture of compounds ranging from 2 to 19 detected compounds, with an 

average of about 8 compounds per sample. 

Concentrations for compounds detected in the source 

water generally were low (less than 1.0 μg/L); four compounds 

(fig. 4) were detected at higher concentrations in ground water 

from four wells. Human-health benchmarks were available 

for 17 of the 25 detected AOCs. Of these 17 compounds, two 

compounds, PCE and trichloroethene (TCE) had benchmark 

quotients greater than or equal to the 1.0 level that identifies 

concentrations of potential concern. 

When comparing analytical results among different 

AOCs, it is important to consider the analytical reporting level 

of each AOC. That is, an AOC with a low reporting level may 

be detected more frequently when compared to other AOCs 

with higher reporting levels. A true comparison is possible, 

however, when comparing individual compounds analyzed 

using the same analytical method (same reporting level). For 

the purposes of this report, comparisons of AOCs are made 

among AOCs regardless of varying reporting levels (Metz 

and others, 2006) to characterize general occurrence rates and 

similarities, or the lack thereof, between AOCs. 

Volatile Organic Compounds

Twelve VOCs were detected in the source-water 

samples (table 1, fig. 4A). Chloroform, the most frequently 

detected compound (87 percent of samples), occurred at low 

concentrations ranging from about 0.02 μg/L to 0.24 μg/L. 

Chloroform is one of the four disinfection by-products (DBPs) 

produced in the highest concentrations during the chlorination 

of drinking water and wastewater. Other associated DBPs 

were detected much less frequently; bromodichloromethane 

was detected in only one sample and, dibromochloromethane 

and bromoform were not detected. The frequent detection 

of chloroform in the study area may be from several sources 

such as chlorinated or reclaimed water used to irrigate lawns 

and gardens; leakage from distribution lines for treated 

drinking water and wastewater, spas, and pools; and leachate 

Consumer Confidence Reports and 

Source Water-Quality Assessments

Since 1999, the U.S. Environmental Protection 

Agency (USEPA) has required water suppliers to provide 

annual drinking-water-quality reports called Consumer 

Confidence Reports (CCRs) to their customers (http://

www.epa.gov/safewater/ccr/ccrfact.html). CCRs are the 

centerpiece of the right-to-know provisions of the 1996 

Amendments to the Safe Drinking Water Act. Each 

CCR provides consumers with fundamental information 

about their drinking water including (1) the source of the 

drinking water; (2) a brief summary of the susceptibility 

to contamination of the local drinking-water source; 

(3) the concentrations (or range of concentrations) of 

any contaminants found in local drinking water, as 

well as their USEPA maximum contaminant levels 

(MCLs), which are legally enforceable drinking-water 

standards and are the highest allowed concentrations of 

contaminants in drinking water, for comparison; and 

(4) phone numbers for additional sources of information.

Information in CCRs is specific to a particular 

water utility. Water utilities analyze finished-water 

samples primarily for regulated contaminants (that is, 

those with MCLs) using USEPA analytical methods 

for the purpose of compliance monitoring. In contrast, 

Source Water-Quality Assessments (SWQAs) performed 

by the USGS are not conducted for compliance 

monitoring, and encompass data from multiple water 

utilities spatially distributed across the Nation. As part 

of SWQAs, both source- and finished-water samples 

are analyzed using USGS analytical methods; source 

water is the raw (ambient) water collected at the surfacewater intake or supply well prior to water treatment, 

and finished water is the treated water sampled prior 

to entering the distribution system. USGS analytical 

methods used in SWQAs typically have lower analytical 

reporting levels than those used in compliance 

monitoring; contaminant detection frequencies reported 

in SWQA reports may therefore be higher than detection 

frequencies for the same contaminants reported in CCRs. 

In SWQAs, concentrations of regulated and unregulated 

contaminants in source and finished water are compared 

to MCLs and HBSLs, respectively. 
8 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Table 1. Detection frequency, maximum concentration, and maximum benchmark quotient value for anthropogenic organic compounds 

detected in 15 community water system wells sampled in Phase I (source water) of the Connecticut source water-quality assessment.

[MRL, Minimum Reporting Level; USEPA, U.S. Environmental Protection Agency; MCL, Maximum Contaminant Level; HBSL, Health-Based Screening 

Level; BQmax, Benchmark Quotient = ratio of maximum compound concentration to MCL or HBSL value; E, estimated value; μg/L, micrograms per liter; 

<, less than; --, not available; A regulated compound is a compound for which federal and(or) state drinking-water standards have been established; an unregulated compound is a compound for which no federal and(or) state drinking-water standards have been established]

Regulated (R) or unregulated (U) 

compound

Chemical 

abstracts 

service registry number

Number of 

samples 

for source 

water

Number 

of detections for 

source 

water

Detection 

frequency 

(percent)

MRL

(μg/L)

Maximum 

concentration for 

source water

(μg/L)

USEPA 

MCL1 or 

HBSL3

(μg/L)

BQmax 

for source 

water

Volatile organic compounds

1,1,1-Trichloroethane (R) 71-55-6 15 10 67 0.032 16.7 200 0.08

1,1,2-Trichloro-1,2,2-

Trifluoroethane (U)

76-13-1 15 2 13 .038 1.06 200,000 .000005

1,1-Dichloroethane (U) 75-34-3 15 4 27 .035 0.12 -- --

1,1-Dichloroethene (R) 75-35-4 15 4 27 .024 .42 7 .06

1,2-Dichloropropane (R) 78-87-5 15 1 7 .029 E .02 5 .004

Bromodichloromethane (R) 75-27-4 15 1 7 .028 E .04 280 .001

Chloroform (R) 67-66-3 15 13 87 .024 .24 280 .003

cis-1,2-Dichloroethene (R) 156-59-2 15 3 20 .024 .17 70 .002

Methyl tert-butyl ether (MTBE) (U) 1634-04-4 15 12 80 .1 .8 -- --

Perchloroethene (PCE) (R) 127-18-4 15 8 53 .03 5.47 5 1

Trichloroethene (TCE) (R) 79-01-6 15 7 47 .038 15.9 5 3

Trichlorofluoromethane (U) 75-69-4 15 1 7 .08 E .04 2,000 .00002

Pesticides

1-Naphthol (U) 90-15-3 15 1 7 .088 E .01 -- --

Atrazine (R) 1912-24-9 15 9 60 .007 .022 3 .007

Carbaryl (U) 63-25-2 15 1 7 .018 E .01 4,000 .000002

Deethylatrazine (U) 6190-65-4 15 9 60 .014 E .026 -- --

Deisopropylatrazine (U) 1007-28-9 15 3 20 .08 E .01 -- --

Imidacloprid (U) 138261-41-3 15 1 7 .02 .014 400 .00004

Metalaxyl (U) 57837-19-1 15 1 7 .007 .009 600 .00002

Metolachlor (U) 51218-45-2 15 5 33 .006 E .007 70 .0001

Prometon (U) 1610-18-0 15 4 27 .01 E .01 100 .0001

Simazine (R) 122-34-9 15 8 53 .005 .008 4 .002

Other anthropogenic organic compounds

Acetyl hexamethyl tetrahydronaphthalene (AHTN) (U)21145-77-7 14 1 7 .5 E .03 -- --

Tri(2-chloroethyl)phosphate 

(TCEP) (U)

115-96-8 14 1 7 .5 E .05 -- --

Triphenyl phosphate (U) 115-86-6 14 2 14 .5 E .07 -- --

1

 U.S. Environmental Protection Agency (2006).

2

 MCL is for total trihalomethanes.

3

 Denotes HBSL (Toccalino and others, 2005).
Anthropogenic Organic Compounds in Source Water 9

Figure 4. Concentration, number of detections, and benchmark quotient values for (A) volatile organic compounds, 

(B) pesticides, and (C) other anthropogenic organic compounds detected in 15 community water system wells 

sampled in Phase I (source water) of the Connecticut source water-quality assessment. NUMBER OF DETECTIONS

10

2

4

4

1

1

13

12

8

7

1

1

3

9

1

9

3

1

1

5

4

8

1

1

2

EXPLANATION

Benchmark quotient value of 0.1—Values equal 

to or greater than this line may warrant 

inclusion of the compound in a low-concentration,

trends-monitoring program

Benchmark quotient value of 1.0—Values greater

than this line indicate concentrations of 

potential human-health concern 

Source water

Finished water—Some values

are equal and therefore plotted 

values overlap

 Non-blended

 Blended 

[Benchmark quotient value is the ratio of the detected concentration of a particular compound to its Maximum 

Contaminant Level, MCL; or Health-Based Screening Level, HBSL]

cis-1,2-Dichloroethene

Trichlorofluoromethane

Trichloroethene

Perchloroethene

Methyl tert-butyl ether

Chloroform

Bromodichloromethane

1,2-Dichloropropane

1,1-Dichloroethene

1,1-Dichloroethane

1,1,2-Trichloro-1,2,2-Trifluoroethane

1,1,1-Trichloroethane

Triphenyl phosphate

Tri(2-chloroethyl)phosphate

Acetyl hexamethyl tetrahydronaphthalene

Simazine

Prometon

Metolachlor

Metalaxyl

Imidacloprid

Deisopropylatrazine

Deethylatrazine

Carbaryl

Atrazine

1-Naphthol

0.001

0.01

0.1

1

10

1e-007

1e-006

1e-005

0.0001

0.001

0.01

0.1

1

CONCENTRATION, IN 

MICROGRAMS PER LITER

BENCHMARK QUOTIENT

A Volatile Organic Compounds

B Pesticides

C Other Anthropogenic Organic Compounds
10 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

from septic-system drain fields (Thiros, 2000; Ivahnenko and 

Barbash, 2004; Zogorski and others, 2006). Other frequently 

detected VOCs include MTBE, a gasoline additive, and the 

solvents 1,1,1-trichloroethane, PCE, and TCE, which are 

commonly used as dry-cleaning agents.

Of the 12 VOCs detected, human-health benchmarks 

were available for 10 compounds (fig. 4A). BQmax values 

for these 10 VOCs typically were several orders of magnitude below 1, but those for two detections were greater than 

1.0 (table 1). PCE had a BQmax value of 1 and TCE had 

a BQmax value of 3 indicating that these two compounds 

may be of potential concern. An HBSL was not available for 

MTBE or 1,1-dichloroethane because human-health toxicity 

information was not available.

Pesticides

Ten pesticide compounds were detected in the source 

water (table 1, fig. 4B). Although the number of individual 

pesticides detected (10) was roughly about the same as for 

VOCs (12), pesticides were detected less frequently in comparison to VOCs (43 pesticide detections compared to 

66 VOC detections). Pesticides also were detected at much 

lower concentrations than VOCs (fig. 4B).

Of the 47 pesticide detections, most (77 percent) were 

derived from triazine herbicides; atrazine (9 detections) and its 

breakdown products deethylatrazine (9 detections), and deisopropylatrazine (3 detections) as well as simazine (8 detections) 

and prometon (4 detections). Several reasons exist for the high 

detection frequency for triazine herbicides, including high 

mobility in sandy soils, widespread use, and persistence in 

ground water (Kruger and others, 1995; Barbash and others, 

1999). The half-life for atrazine in soils can be more than 

100 days, and in ground water, atrazine and deethylatrazine 

can persist for almost 6 years and more than 25 years, respectively (Denver and Sandstrom, 1991; Gaus, 2000).

Of the 10 pesticides detected, human-health benchmarks 

were available for 7 of these compounds (table 1, fig. 4B). 

BQmax values for these seven pesticides typically were 

several orders of magnitude below 1.0 and none were greater 

than 0.1 (table 1). Atrazine had the highest calculated BQ 

value of 0.007. 

Other Anthropogenic Organic Compounds

Three OAOCs were detected in the source-water samples—acetyl hexamethyl tetrahydronaphthalene (AHTN), 

tri(2-chloroethyl)phosphate, and triphenyl phosphate—and 

concentrations were low (table 1, fig. 4C). Triphenyl phosphate had the highest detected concentration, estimated at 

0.07 μg/L. None of the three OAOCs detected have associated 

human-health benchmark values available. 

Anthropogenic Organic Compounds in 

Source and Associated Finished Water

Ten of the original 15 CWS wells with AOC detections 

were resampled during the Phase II of this study along with 

their associated finished water during June or July 2004. 

Of the 10 finished-water sources sampled, 3 were blended 

with water from other CWS wells, and 7 were not blended. 

Because water from these CWSs was analyzed only for 

those AOCs that occurred most frequently during the first 

phase of sampling, not all pairs of CWS wells and associated 

finished water were sampled the same number of times for the 

same AOCs. That is, 8 pairs of source-water and associated 

finished-water samples were analysed for VOCs, 8 to 10 

pairs were analyzed for pesticides, and 8 source-water and 9 

finished-water samples were analyzed for OAOCs. Three of 

the finished-water samples represented water blended with 

water from other CWS wells prior to treatment, and five were 

not blended. Generally, where eight finished-water samples 

were collected, three were from blended sources and five were 

not blended.

Because the process used to select CWS wells in Phase II 

was biased to those compounds that occurred most frequently, 

and because this process resulted in a small number of 

samples, characterization of the overall occurrence of these 

compounds in source water and finished water is not feasible. 

Consequently, a general comparison of these compounds in 

source water and finished water is presented. For interpretive 

purposes, selected finished-water results were separated into 

blended and non-blended waters. This differentiation provides 

additional insight into the effect of blending on finished-water 

quality and allows for examination of occurrence findings 

separately for CWSs that do not blend with those that do 

blend. Concentrations of each AOC detected in source water 

and the associated blended or non-blended finished water are 

presented in appendix 1.

Volatile Organic Compounds

A total of 19 VOCs were detected in either the source 

water or the finished water (table 2; appendix 1). Specifically, 

four VOCs were detected only in source water, four only in 

finished water, and 11 VOCs were detected in both sourceand finished-water samples (table 2, fig. 5). DBPs accounted 

for most of the VOC detections, with all concentrations less 

than 1 μg/L and benchmark quotient values less than 0.01. 

DBPs are regulated by the USEPA with an MCL of 80 μg/L 

for the sum of all four compounds (U.S. Environmental 

Protection Agency, 2006). Chloroform, the most frequently 

detected VOC, was detected in all source- and finished-water 

samples. Bromoform was undetected in source-water samples; 

however, it was detected in four finished-water samples. 

Dibromochloromethane was undetected in all source-water 

samples and detected in five finished-water samples, one of 

which was from blended sources. 
Anthropogenic Organic Compounds in Source and Associated Finished Water 11

Figure 5. (A) Concentrations and number of detections and (B) benchmark quotient values for volatile 

organic compounds detected in 10 community water system wells sampled in Phase II (source and 

finished water) of the Connecticut source water-quality assessment. 1e-005 0.0001 0.001 0.01 0.1

1

10

CONCENTRATION, IN MICROGRAMS PER LITER

tert-Amyl methyl ether

m- & p-xylene

cis-1,2-Dichloroethene

Trichlorofluoromethane

Trichloroethene

Toluene

Perchloroethene

Methyl tert-butyl ether

Ethyl tert-butyl ether

Dibromochloromethane

Chloroform

Carbon disulfide

Bromoform

Bromodichloromethane

1,2-Dichloropropane

1,1-Dichloroethene

1,1-Dichloroethane

1,1,2-Trichloro-1,2,2-Trifluoroethane

1,1,1-Trichloroethane

1e-0071e-0061e-005

0.0001

0.001

0.01

0.1

1

BENCHMARK QUOTIENT VALUE

tert-Amyl methyl ether

m- & p-xylene

cis-1,2-Dichloroethene

Trichlorofluoromethane

Trichloroethene

Toluene

Perchloroethene

Methyl tert-butyl ether

Ethyl tert-butyl ether

Dibromochloromethane

Chloroform

Carbon disulfide

Bromoform

Bromodichloromethane

1,2-Dichloropropane

1,1-Dichloroethene

1,1-Dichloroethane

1,1,2-Trichloro-1,2,2-Trifluoroethane

1,1,1-Trichloroethane

[Benchmark quotient value is the ratio of the detected concentration of a particular compound to its Maximum 

Contaminant Level, MCL; or Health-Based Screening Level, HBSL]

B 

A 

NUMBER OF DETECTIONS

(source, finished)

5, 4

1, 0

3, 1

2, 1

1, 0 

1, 5 

1, 0

8, 8

0, 4

0, 5

1, 1

3, 2

6, 4

0, 1

4, 3

1, 0

0, 1

1, 1

3, 2

EXPLANATION

Benchmark quotient value of 0.1—Values equal 

to or greater than this line may warrant 

inclusion of the compound in a low-concentration,

trends-monitoring program

Source water

Finished water—Some values

are equal and therefore plotted 

values overlap

 Non-blended

 Blended 

Benchmark quotient value of 1.0—Values greater

than this line indicate concentrations of 

potential human-health concern 
12 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004 Table 2. Detection frequency, maximum concentration, and maximum benchmark quotient value for anthropogenic organic compounds detected in 10 community water system wells sampled in Phase II (source and finished water) of the Connecticut source water-quality assessment.—Continued [MRL, Minimum Reporting Level; USEPA, U.S. Environmental Protection Agency; MCL, Maximum Contaminant Level; HBSL, Health-Based Screening Level; BQmax, Benchmark Quotient = ratio of maximum compound concentration to MCL or HBSL value; E, estimated value; μg/L, micrograms per liter; <, less than; --, not available; A regulated compound is a compound for which federal and(or) state drinking-water standards have been established; an unregulated compound is a compound for which no federal and(or) state drinking-water standards have been established] Regulated (R) or unregulated (U) compound Chemical abstracts ser- vice registry number Num- ber of samples (Source water) Num- ber of samples (Finished water) Number of de- tections (Source water) Number of detec- tions (Finished water) Percent detec- tions (Source water) Percent detec- tions (Finished water) MRL (μg/L) Maximum concen- tration for source water (μg/L) Maximum concen- tration for finished water (μg/L USEPA MCL1 or HBSL3 (μg/L) BQmax (Source water) BQmax (Fin- ished water) Volatile organic compounds 1,1,1-Trichloroethane (R) 71-55-6 8 8 5 4 63 50 0.032 3.54 1.12 200 0.02 0.006 1,1,2-Trichloro-1,2,2- Trifluoroethane (U) 76-13-1 8 8 1 0 13 0 .038 0.39 -- 200,000 .000002 -- 1,1-Dichloroethane (U) 75-34-3 8 8 3 1 38 13 .035 .14 0.13 -- -- -- 1,1-Dichloroethene (R) 75-35-4 8 8 2 1 25 13 .024 .11 .1 7 .02 .01 1,2-Dichloropropane (R) 78-87-5 8 8 1 0 13 0 .029 E .03 -- 5 .006 -- Bromodichloromethane (R) 75-27-4 8 8 1 5 13 63 .028 E .03 .5 280 .0004 .006 Bromoform (R) 75-25-2 8 8 0 4 0 50 .1 -- E .22 280 -- .003 Carbon Disulfide (U) 75-15-0 8 8 1 0 13 0 .038 E .03 -- 700 .00004 -- Chloroform (R) 67-66-3 8 8 8 8 100 100 .024 .22 .72 280 .003 .009 cis-1,2-Dichloroethene (R) 156-59-2 8 8 3 2 38 25 .024 .16 E .04 70 .002 .001 Dibromochloromethane (R) 124-48-1 8 8 0 5 0 63 .1 -- .5 280 -- .006 Ethyl tert-butyl ether (ETBE) (U) 637-92-3 8 8 1 1 13 13 .03 .24 .15 -- -- --

m- & 

p-xylene (R)

m = 106-42-3p = 108-38-3

8 8 0 1 0 13 .06 -- E .02 10,000 -- .000002

Methyl tert-butyl ether (MTBE) (U) 1634-04-4 8 8 3 2 38 25 .1 7.8 6 -- -- --tert-Amyl methyl ether (TAME) (U) 994-05-8 8 8 1 1 13 13 .04 .94 .66 -- -- --Perchloroethene (PCE) (R) 127-18-4 8 8 6 4 75 50 .03 8.02 .54 5 2 .1Toluene (R) 108-88-3 8 8 0 1 0 13 .02 -- E .04 1,000 -- .00004Trichloroethene (TCE) (R) 79-01-6 8 8 4 3 50 38 .038 4.31 .29 5 .9 .06Trichlorofluoromethane (U) 75-69-4 8 8 1 0 13 0 .08 E .13 -- 2,000 .00006 --

Pesticides

2-Hydroxyatrazine (U) 2163-68-0 8 6 2 2 25 33 .032 .008 .006 70 .0001 .000093,4-Dichloroaniline (U) 95-76-1 8 8 0 1 0 13 .005 -- E .003 -- -- --

4-Chloro-2-methylphenol (U) 1570-64-5 8 8 0 1 0 13 .005 -- E .004 -- -- --
Anthropogenic Organic Compounds in Source and Associated Finished Water 13

Table 2. Detection frequency, maximum concentration, and maximum benchmark quotient value for anthropogenic organic compounds detected in 10 community water system wells sampled in Phase II (source and finished water) of the Connecticut source water quality assessment.—Continued[MRL, Minimum Reporting Level; USEPA, U.S. Environmental Protection Agency; MCL, Maximum Contaminant Level; HBSL, Health-Based Screening Level; BQmax, Benchmark Quotient = ratio of maximum compound concentration to MCL or HBSL value; E, estimated value; μg/L, micrograms per liter; <, less than; --, not available; A regulated compound is a compound for which federal and(or) state drinking-water standards have been established; an unregulated compound is a compound for which no federal and(or) state drinking-water standards have been established]

Regulated (R) or unregulated (U) 

compound

Chemical 

abstracts 

service 

registry 

number

Number of 

samples 

(Source 

water)

Number of 

samples 

(Finished 

water)

Number 

of detections 

(Source 

water)

Number 

of detections 

(Finished 

water)

Percent 

detections 

(Source 

water)

Percent 

detections 

(Finished 

water)

MRL

(μg/L)

Maximum 

concentration for 

source 

water

(μg/L)

Maximum 

concentration for 

finished 

water

(μg/L

USEPA 

MCL1 or 

HBSL3

(μg/L)

BQmax 

(Source 

water)

BQmax 

(Finished 

water) 

Pesticides—Continued

Atrazine (R) 1912-24-9 8 8 7 6 88 75 0.007 0.021 0.03 3 0.007 0.01Bentazon (U) 25057-89-0 8 6 1 1 13 17 .024 E .01 E .01 200 .00005 .00005Deethylatrazine (U) 6190-65-4 8 8 7 7 88 88 .014 E .016 E .019 -- -- --Diazinon (U) 333-41-5 10 10 1 1 10 10 .005 .01 .005 -- -- --Fipronil (U) 120068-37-3 8 8 2 0 25 0 .016 E .006 -- -- -- --Fipronil sulfide (U) 120067-83-6 8 8 1 1 13 13 .013 E .007 E .007 -- -- --Imidacloprid (U) 138261-41-3 8 6 1 0 13 0 .02 E .006 -- 400 .00002 --Metalaxyl (U) 57837-19-1 8 8 1 1 13 13 .007 .01 .071 600 .00002 .0001Metolachlor (U) 51218-45-2 10 10 2 1 20 10 .006 E .006 E .002 70 .00009 .00003Oryzalin (U) 19044-88-3 8 6 0 1 0 17 .023 -- E .07 400 -- .0002Prometon (U) 1610-18-0 10 10 3 3 30 30 .01 E .01 E .01 100 .0001 .0001Simazine (R) 122-34-9 8 8 6 6 75 75 .005 .008 .011 4 .002 .003

Other anthropogenic organic compounds

Acetyl hexamethyl tetrahydronaphthalene (AHTN) (U) 21145-77-7 8 9 1 2 13 22 .5 E .1 E .1 -- -- --Bisphenol A (U) 80-05-7 8 9 3 4 38 44 1 2 E .45 400 .006 .001Hexahydrohexamethylcyclopentabenzopyran (HHCB) (U) 1222-05-5 8 9 1 0 13 0 .5 E .1 -- -- -- --Methyl salicylate (U) 119-36-8 8 9 0 1 0 11 .5 -- E .1 -- -- --4-Nonylphenol, diethoxy- (U) 26027-38-2 8 9 1 0 13 0 5 E 3 -- -- -- --Tri(2-chloroethyl)phosphate 

(TCEP) (U)

115-96-8 8 9 1 1 13 11 .5 E .1 E .1 -- -- --

Tributyl phosphate (U) 126-73-8 8 9 1 0 13 0 .5 E .2 -- -- -- --Triphenyl phosphate (U) 115-86-6 8 9 1 0 13 0 .5 E .1 -- -- -- --

1 U.S. Environmental Protection Agency (2006).2 MCL is for total trihalomethanes.3 Denotes HBSL (Toccalino and others, 2005).
14 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Other detected VOCs included 1,1,1-trichloroethane, 

which was detected in five source-water samples and four 

finished-water samples. The maximum concentration was 

3.54 μg/L in source water and 1.12 μg/L in finished water. Of 

the five source-water detections, three also were detected in 

the associated finished water. This compound in one finishedwater sample from blended sources was undetected in the 

associated source-water sample. MTBE was detected in three 

source-water samples with a maximum concentration of 

7.8 μg/L and was detected in two finished-water samples with 

a maximum concentration of 6.0 μg/L. 

The solvents PCE and TCE had the highest calculated 

benchmark quotients of any VOC. PCE was detected in six 

source-water samples with a maximum concentration of 

8.02 μg/L and a BQ value of 2 and two measured concentrations greater than 0.5 μg/L and BQ values greater than 0.1. 

PCE also was detected in four finished-water samples, one of 

which had a concentration of 0.54 μg/L and a BQ value of 0.1. 

TCE was detected in four source-water samples, one of which 

had a concentration of 4.31 μg/L with a BQ value of 0.9; however, the highest of three detections in finished water was only 

0.29 μg/L with a BQ value of 0.06. 

Pesticides

A total of 15 pesticides were detected in either the source 

water or the associated finished water (table 2; appendix 1). 

Most pesticide detections were triazine herbicides (table 2, 

fig. 6) or their degradation products, including atrazine and 

deethylatrazine, which were detected in most source- and 

finished-water samples. 2-Hydroxyatrazine was detected in 

both source- and finished water at one site, in source water 

at one site where the finished water was not sampled, and in 

finished water at one site where the water was from a blended 

source. Deethylatrazine was detected in both source- and 

finished-water samples at seven sites, prometon in three source 

samples and their associated finished water samples, and 

simazine in six source samples and their associated finished 

water. Of 34 pesticide detections in source water and 32 detections in finished water, 27 were in both the source water and 

the associated finished water. The highest BQ value of 0.01 for 

a triazine herbicide was from a blended-source finished-water 

sample for atrazine (appendix 1). 

Diazinon and metalaxyl are also of interest because they 

were detected above the MRL in one sample each in both 

source water and the associated finished water.

Other Anthropogenic Organic Compounds

Eight OAOCs were detected in source or finished water 

(table 2, fig. 7, appendix 1): acetyl hexamethyl tetrahydronaphthalene, bisphenol A, hexahydrohexamethylcyclypentabenzopyran (HHCB), methyl salicylate, tri(2-chloroethyl)

phosphate, tributyl phosphate, and triphenyl phosphate. All 

concentrations were low. Bisphenol A was the most frequently 

detected OAOC, with three detections in source water and 

four in finished water. It was the only detected OAOC with an 

associated Benchmark Quotient, with a maximum BQ value of 

0.006, well below levels of potential concern.
Anthropogenic Organic Compounds in Source and Associated Finished Water 15

Figure 6. (A) Concentrations and number of detections and (B) benchmark quotient values for 

pesticides detected in 10 community water system wells sampled in Phase II (source and finished 

water) of the Connecticut source water-quality assessment. 1e-005 0.0001 0.001 0.01 0.1

1

10

CONCENTRATION, IN MICROGRAMS PER LITER

Simazine

Prometon

Oryzalin

Metolachlor

Metalaxyl

Imidacloprid

Fipronil sulfide

Fipronil

Diazinon

Deethylatrazine

Bentazon

Atrazine

4-Chloro-2-methylphenol

3,4-Dichloroaniline

2-Hydroxyatrazine

1e-007

1e-0061e-005

0.0001

0.001

0.01

0.1

1

Simazine

Prometon

Oryzalin

Metolachlor

Metalaxyl

Imidacloprid

Fipronil sulfide

Fipronil

Diazinon

Deethylatrazine

Bentazon

Atrazine

4-Chloro-2-methylphenol

3,4-Dichloroaniline

2-Hydroxyatrazine

A 

B

NUMBER OF DETECTIONS

(source, finished)

2, 2

0, 1

0, 1

7, 6

1, 1 

7, 7 

2, 0

1, 1

1, 1

1, 0

1, 1

2, 1

0, 1

3, 3

6, 6

BENCHMARK QUOTIENT VALUE

[Benchmark quotient value is the ratio of the detected concentration of a particular compound to its Maximum 

Contaminant Level, MCL; or Health-Based Screening Level, HBSL]

EXPLANATION

Benchmark quotient value of 0.1—Values equal 

to or greater than this line may warrant 

inclusion of the compound in a low-concentration,

trends-monitoring program

Benchmark quotient value of 1.0—Values greater

than this line indicate concentrations of 

potential human-health concern 

Source water

Finished water—Some values

are equal and therefore plotted 

values overlap

 Non-blended

 Blended
16 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Figure 7. (A) Concentrations and number of detections and (B) benchmark quotient values for other anthropogenic 

organic compounds detected in 10 community water system wells sampled in Phase II (source and finished water) 

of the Connecticut source water-quality assessment. 1e-005 0.0001

0.001

0.01

0.1

1

10

CONCENTRATION, IN MICROGRAMS PER LITER

Triphenyl phosphate

Tributyl phosphate

Tri(2-chloroethyl)phosphate

4-Nonylphenol, diethoxylate

Methyl salicylate

Hexahydrohexamethylcyclopentabenzopyran (HHCB)

Bisphenol A

Acetyl hexamethyl tetrahydronaphthalene

1e-0071e-0061e-005

0.0001

0.001

0.01

0.1

1

Triphenyl phosphate

Tributyl phosphate

Tri(2-chloroethyl)phosphate

4-Nonylphenol, diethoxylate

Methyl salicylate

Hexahydrohexamethylcyclopentabenzopyran (HHCB)

Bisphenol A

Acetyl hexamethyl tetrahydronaphthalene

BENCHMARK QUOTIENT VALUE

[Benchmark quotient value is the ratio of the detected concentration of a particular compound to its Maximum 

Contaminant Level, MCL; or Health-Based Screening Level, HBSL]

B 

A 

NUMBER OF DETECTIONS

(source, finished)

1, 2

3, 4

1, 0

0, 1

1, 0 

1, 1 

1, 0

1, 0

EXPLANATION

Benchmark quotient value of 0.1—Values equal 

to or greater than this line may warrant 

inclusion of the compound in a low-concentration,

trends-monitoring program

Benchmark quotient value of 1.0—Values greater

than this line indicate concentrations of 

potential human-health concern 

Source water

Finished water—Some values

are equal and therefore plotted 

values overlap

 Non-blended

 Blended 
References Cited 17

Oakdale Manor, Aquarion Water of Connecticut, Southbury 

Training School, Heritage Village, Unionville Water Company, 

Southington Water Company, and South Central Regional 

Water Authority.

References Cited

Barbash, J.E., Thelin, G.P., Kolpin, D.W., and Gilliom, R.J., 

1999, Distribution of major herbicides in ground water of 

the United States: U.S. Geological Survey Water-Resources 

Investigations Report 98–4245, 57 p. 

Barbash, J.E., and Resek, E.A., 1996, Pesticides in ground 

water—Distribution, trends, and governing factors: Chelsea, Mich., Ann Arbor Press, Pesticides in the Hydrologic 

System Series, v. 2, 590 p.

Connor, B.F., Rose, D.L., Noriega, M.C., Murtagh, L.K., and 

Abney, S.R., 1998, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of 86 volatile organic compounds in water by gas 

chromatography/mass spectrometry, including detections 

less than reporting limits: U.S. Geological Survey OpenFile Report 97–829, 78 p.

Denver, J.M., and Sandstrom, M.W., 1991, Distribution of 

dissolved atrazine and two metabolites in the unconfined 

aquifer, southeastern Delaware, in Mallard, G.E., and 

Aronson, D.A., eds., U.S. Geological Survey Toxic 

Substances Hydrology Program—Proceedings of the 

technical meeting, Monterey, Calif., March 11–15, 1991: 

U.S. Geological Survey Water-Resources Investigations 

Report 91–4034, p. 314–318.

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-phase extraction and 

high-performance liquid chromatography/mass spectrometry: U.S. Geological Survey Water-Resources Investigations 

Report 01–4134, 73 p.

Gaus, Irena, 2000, Effects of water extraction in a vulnerable 

phreatic aquifer—Consequences for groundwater contamination by pesticides, Sint-Jansteen area, The Netherlands: 

Journal of Hydrology, v. 8, p. 218–229.

Herberer, Thomas, 2002, Occurrence, fate, and removal of 

pharmaceutical residues in the aquatic environment—

A review of recent research data: Toxicology Letters, 

v. 131, p. 5–17.

Summary

The U.S. Geological Survey conducted a source waterquality assessment (SWQA) study of ground water sampled 

from community water system (CWS) wells in western and 

central Connecticut. Fifteen CWS wells, screened in the 

unconfined glacial stratified aquifer, were sampled during Phase I of the study during 2002–2004 to determine the 

occurrence of 258 anthropogenic organic compounds (AOCs). 

During Phase II of the study, samples from 10 of the original 

15 wells along with samples of the associated finished water 

were collected in June or July 2004 to compare the detection 

frequency and concentration of selected AOCs between source 

and finished water. 

During Phase I of the study, 25 individual AOCs were 

detected (12 volatile organic compounds (VOCs), 10 pesticides, and 3 other anthropogenic organic compounds 

(OAOCs)). The most frequently occurring AOCs were 

detected in more than half of the 15 source-water samples 

and included chloroform (87 percent), methyl tert-butyl ether 

(MTBE, 80 percent), 1,1,1-trichloroethene (67 percent), atrazine (60 percent) deethylatrazine (60 percent), perchloroethene 

(PCE, 53 percent), and simazine (53 percent). Samples 

generally contained a mixture of compounds ranging from 2 

to 19 detected compounds, with an average of about 8 compounds per sample. Concentrations for compounds detected 

in the source water generally were low; four compounds were 

detected at concentrations of 1 microgram per liter (μg/L) or 

greater in water from four wells. 

Ten of the original 15 CWS wells that had AOC 

detections were resampled during Phase II of this SWQA 

along with the associated finished water. A total of 19 VOCs 

were detected in either the source water or the finished 

water. Disinfection by-products of trihalomethane accounted 

for most of the VOC detections, with all concentrations 

less than 1 μg/L and benchmark quotient values less than 

0.01. Chloroform, the most frequently detected VOC, was 

detected in all source- and finished-water samples. Other 

detected VOCs included MTBE, a gasoline additive, and 

the solvents 1,1,1-trichloroethane, perchloroethene (PCE) 

and trichloroethene (TCE). Most of the detected pesticides 

were triazine herbicides such as atrazine or their degradation 

products, which were detected in most source- and finishedwater samples. Eight OAOCs were detected in source or 

finished water samples at low concentrations.

Acknowledgments

We are grateful to the many public and private organizations for providing information pertaining to the wells 

used in this study and for permitting the collection of water 

samples for analyses. In particular, we wish to thank the water 

managers and engineers for Woodbury Place, Woodlake Tax 

District, United Water Company, Watertown Fire District, 
18 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Starn, J.J., and Stone, J.R., 2005, Simulation of groundwater flow to assess geohydrologic factors and their effect 

on source-water areas for bedrock wells in Connecticut: 

U.S. Geological Survey Scientific Investigations Report 

2004–5132, 78 p., online only at http://pubs.usgs.gov/

sir/2004/5132/

Ternes, T.A., Meisenheimer, M., McDowell, D., Sacher, F., 

Branch, H.J., Hsiate-Guide, B., Preuss, G., Wilme, U., and 

Zulei-Seibert, N., 2002, Removal of pharmaceuticals during drinking water treatment: Environmental Science and 

Technology, v. 36, p. 3855–3863.

Thiros, S.A., 2000, Quality of shallow ground water in areas 

of recent residential and commercial development in 

Salt Lake Valley, Utah, 1999: U.S. Geological Survey 

Fact Sheet 106–00, 6 p.

Toccalino, P.L., Norman, J.E., Phillips, R.H., Kauffman, L.J., 

Stackelberg, P.E., Nowell, L.H., Krietzman, S.J., and 

Post, G.B., 2004, Application of health-based screening 

levels to ground-water quality data in a state-scale pilot 

effort: U.S. Geological Survey Scientific Investigations 

Report 2004–5174, 64 p.

Toccalino, P.L., Nowell, Lisa, Wilber, W.G., Zogorski, J.S., 

Donohue, Joyce, Eiden, Catherine, Krietzman, S.J., and 

Post, G.B., 2003, Development of health-based screening 

levels for use in State- or local-scale water-quality assessments: U.S. Geological Survey Water-Resources Investigations Report 03–4054, 22 p.

Toccalino, P.L., Zogorski, J.S., and Norman, J.E., 2005, 

Health-based screening levels and their application to 

water-quality data: U.S. Geological Survey Fact Sheet 

2005–3059, 2 p. 

U.S. Census Bureau, 2002, 2000 census of population and 

housing, summary population and housing characteristics: 

Washington, D.C., Bureau of the Census, publication 

PHC-1-8, Connecticut, 87 p., at http://www.census.gov/

prod/cen2000/phc-1-8.pdf

U.S. Environmental Protection Agency, 2002, Setting standards for safe drinking water: U.S. Environmental Protection Agency, Office of Ground Water and Drinking Water: 

Washington, D.C., updated November 26, 2002, accessed 

January 7, 2005, at http://www.epa.gov/safewater/standard/

setting.html

U.S. Environmental Protection Agency, 2006, Title 40—

Protection of Environment, Chapter I Environmental Protection Agency, Part 141—National primary drinking water 

regulations: Washington, D.C., at http://www.access.gpo.

gov/nara/cfr/waisidx_02/40cfr141_02.html

Ivahnenko, Tamara, and Barbash, J.E., 2004, Chloroform in 

the hydrologic system—Sources, transport, fate, occurrence, and effects on human health and aquatic organisms: 

U.S. Geological Survey Scientific Investigations Report 

2004–5137, 34 p.

Koterba, M.T., Wilde, F.D., and Lapham, W.W., 1995, 

Ground-water-data-collection protocols and procedures for 

the National Water-Quality Assessment Program collection 

and documentation of water quality samples and related 

data: U.S. Geological Survey Open-File Report 95–399, 

113 p.

Kruger, E.L., Zhu, Beilei, and Coats, J.R., 1995, Relative 

mobilities of atrazine, five atrazine degradates, metolachlor, 

and simazine in soils of Iowa: Environmental Toxicology 

and Chemistry, v. 15, no. 5, p. 691–695.

Lindley, C.E., Stewart, J.T., and Sandstrom, M.W., 1996, 

Determination of low concentrations of acetochlor in water 

by automated solid-phase extraction and gas chromatography with mass selective detection: Journal of Association 

of Official Analytical Chemists International, v. 79, no. 4, 

p. 962–966.

Loraine, G.A., and Pettigrove, M.E., 2006, Seasonal variations in concentrations of pharmaceuticals and personal 

care products in drinking water and reclaimed wastewater in 

southern California: Environmental Science and Technology, v. 40, p. 687–695.

Madsen, J.E., Sandstrom, M.W., and Zaugg, S.D., 2003, 

Methods of analysis by the U.S. Geological Survey National 

Water Quality Laboratory—A method supplement for the 

determination of fipronil and degradates in water by gas 

chromatography/mass spectrometry: U.S. Geological 

Survey Open-File Report 02–462, 11 p.

Metz, P.A., Delzer, G.C., Berndt, M.P., Crandall, C.A., and 

Toccalino, P.L., 2007, Anthropogenic organic compounds 

in ground water and finished water of community water 

systems in the northern Tampa Bay area, Florida, 2002–04: 

U.S. Geological Survey Scientific Investigations Report 

2006–5267, 48 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.

Stackelberg, P.E., Furlong, E.T., Meyer, M.T., Zaugg, S.D., 

Henderson, A.K., Reissman, D.B., 2004, Persistence of 

pharmaceutical compounds and other organic wastewater 

contaminants in a conventional drinking-water-treatment 

plant: Science of the Total Environment, v. 329, no. 1–3, 

p. 99–113.
References Cited 19

Westerhoff, Paul, Yoon, Yeomin, Snyder, Shane, Wert, Eric, 

2005, Fate of endocrine-disruptor, pharmaceutical, and 

personal care product chemicals during simulated drink-

ing water treatment processes: Environmental Science and 

Technology, v. 39, no. 17, p. 6649–6663.

Zaugg, S.D., Smith, S.G., Schroeder, M.P., Barber, L.B., and 

Burkhardt, M.R., 2002, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory—

Determination of wastewater compounds by polystyrenedivinylbenzene solid-phase extraction and capillary-column 

gas chromatography/mass spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 01–4186, 

37 p.

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

K.M., 1995, Methods of analysis by the U.S. Geological 

Survey National Water Quality Laboratory—Determination 

of pesticides in water by C-18 solid-phase extraction and 

capillary-column gas chromatography/mass spectrometry 

with selected-ion monitoring: U.S. Geological Survey 

Open-File Report 95–181, 60 p.

Zogorski, J.S., Carter, J.M., Ivahnenko, Tamara, Lapham, 

W.W., Moran, M.J., Rowe, B.L., Squillace, P.J., and 

Toccalino, P.L., 2006, The quality of our Nation’s waters—

Volatile organic compounds in the Nation’s ground water 

and drinking-water supply wells: U.S. Geological Survey 

Circular 1292, 101 p.

B

Benchmark Quotient (BQ) Ratio of the 

concentration of a contaminant to its 

Maximum Contaminant Level (MCL) value 

for a regulated compound or to its Health 

Based-Screening Level (HBSL) value for an 

unregulated compound. BQs greater than 1.0 

identify concentrations of potential concern. 

BQs greater than 0.1 identify compounds that 

may warrant inclusion in a low-concentration, 

trends-monitoring program.

BQmax Ratio of the maximum concentration 

of a contaminant to its MCL or HBSL value. 

Blended Water As used in this report, 

finished water that has been blended with 

one or more different ground-water sources. 

Finished water blended with surface water was 

not sampled as part of this study.

C

Concentration of Potential Human-Health 

Concern As used in this report: (1) for a 

regulated compound with a U.S. Environmental 

Protection Agency (USEPA) drinking-water 

standard, a concentration greater than the 

Maximum Contaminant Level; and (2) for an 

unregulated compound, a concentration greater 

than the Health-Based Screening Level.

Community Water System (CWS) A public 

water system with 15 or more connections and 

serving 25 or more year-round residents and 

thus is subject to USEPA regulations enforcing 

the Safe Drinking Water Act. A CWS serves a 

residential population, such as a municipality, 

mobile home park, or nursing home.

D

Drinking-Water Guideline As used in this 

report, a threshold concentration that has no 

regulatory status, but is issued in an advisory 

capacity by the USEPA or State agencies.

Drinking-Water Standard As used in this 

report, a threshold concentration that is legally 

enforceable (such as MCLs) by the USEPA or 

State agencies.

F

Finished Water Water is “finished” when 

it has passed through all the processes in a 

water treatment plant and is ready to be delivered to consumers.

H

Health-Based Screening Level (HBSL) An 

estimate of a benchmark concentration (for a 

noncarcinogen) or concentration range (for a 

carcinogen) in water that (1) may be of potential human-health concern; (2) can be used as 

a threshold value against which measured concentrations of contaminants in water samples 

can be compared; and (3) is consistent with 

USEPA Office of Water methodologies.

Human-Health Benchmarks As used in this 

report, these include USEPA MCL values and 

HBSL values developed collaboratively by the 

U.S. Geological Survey, USEPA, New Jersey 

Department of Environmental Protection, and 

Oregon Health & Science University.

M

Maximum Contaminant Level (MCL) As used 

in this report, a USEPA drinking-water standard 

that is legally enforceable, and that sets the 

maximum permissible level of a contaminant 

in water that is delivered to any user of a public 

water system at which no known or anticipated 

adverse effect on the health of persons occurs 

and which allows an adequate margin of safety.

R

Regulated Compound As used in this report, a 

compound for which a Federal drinking-water 

standard has been established.

S

Source Water The raw (ambient) water 

collected at the supply well or surface-water 

intake prior to any treatment used to produce 

finished water.

U

Unregulated Compound As used in this 

report, a compound for which no Federal 

drinking-water standard has been established. 

Note that a compound that is unregulated under 

the Safe Drinking Water Act may be regulated 

in other contexts and under other statutes.

Glossary

Appendix 1. Concentration and Benchmark Quotient Values 

for Detected Anthropogenic Organic Compounds in 

Samples of Source Water and Associated Finished Water, 

Connecticut SWQA Study
24 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds

3 6/18/04 10:15 AM 1,1,1-Trichloroethane (R) < 0.032 < 0.032

4 7/15/04 11:15 AM 1,1,1-Trichloroethane (R) < 0.032 E 0.01169 E 0.00006

5 7/30/04 11:40 AM 1,1,1-Trichloroethane (R)

7 7/23/04 10:00 AM 1,1,1-Trichloroethane (R) 3.538 0.02 E 0.08324 E 0.0004

8 7/14/04 10:00 AM 1,1,1-Trichloroethane (R) < 0.032 < 0.032

9 6/23/04 10:30 AM 1,1,1-Trichloroethane (R)

10 6/17/04 10:45 AM 1,1,1-Trichloroethane (R) E 0.03825 E 0.0002 < 0.032

11 6/22/04 10:30 AM 1,1,1-Trichloroethane (R) 0.1669 0.0008 < 0.032

12 6/22/04 1:30 PM 1,1,1-Trichloroethane (R) E 0.04598 E 0.0002 E 0.04398 E 0.0002

14 6/29/04 10:40 AM 1,1,1-Trichloroethane (R) 1.144 0.006 1.124 0.006

3 6/18/04 10:15 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

4 7/15/04 11:15 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

5 7/30/04 11:40 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U)

7 7/23/04 10:00 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) 0.3939 0.000002 < 0.038

8 7/14/04 10:00 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

9 6/23/04 10:30 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U)

10 6/17/04 10:45 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

11 6/22/04 10:30 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

12 6/22/04 1:30 PM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

14 6/29/04 10:40 AM 1,1,2-Trichloro-1,2,2-Trifluoroethane (U) < 0.038 < 0.038

3 6/18/04 10:15 AM 1,1-Dichloroethane (U) < 0.035 < 0.035

4 7/15/04 11:15 AM 1,1-Dichloroethane (U) < 0.035 < 0.035

5 7/30/04 11:40 AM 1,1-Dichloroethane (U)

7 7/23/04 10:00 AM 1,1-Dichloroethane (U) E 0.03387 < 0.035

8 7/14/04 10:00 AM 1,1-Dichloroethane (U) < 0.035 < 0.035

9 6/23/04 10:30 AM 1,1-Dichloroethane (U)

10 6/17/04 10:45 AM 1,1-Dichloroethane (U) < 0.035 < 0.035

11 6/22/04 10:30 AM 1,1-Dichloroethane (U) E 0.06816 < 0.035

12 6/22/04 1:30 PM 1,1-Dichloroethane (U) < 0.035 < 0.035

14 6/29/04 10:40 AM 1,1-Dichloroethane (U) 0.1396 0.1324
Appendix 1 25

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM 1,1-Dichloroethene (R) < 0.024 < 0.024

4 7/15/04 11:15 AM 1,1-Dichloroethene (R) < 0.024 < 0.024

5 7/30/04 11:40 AM 1,1-Dichloroethene (R)

7 7/23/04 10:00 AM 1,1-Dichloroethene (R) E 0.0555 E 0.008 < 0.024

8 7/14/04 10:00 AM 1,1-Dichloroethene (R) < 0.024 < 0.024

9 6/23/04 10:30 AM 1,1-Dichloroethene (R)

10 6/17/04 10:45 AM 1,1-Dichloroethene (R) < 0.024 < 0.024

11 6/22/04 10:30 AM 1,1-Dichloroethene (R) < 0.024 < 0.024

12 6/22/04 1:30 PM 1,1-Dichloroethene (R) < 0.024 < 0.024

14 6/29/04 10:40 AM 1,1-Dichloroethene (R) 0.1146 0.02 0.1003 0.01

3 6/18/04 10:15 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

4 7/15/04 11:15 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

5 7/30/04 11:40 AM 1,2-Dichloropropane (R)

7 7/23/04 10:00 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

8 7/14/04 10:00 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

9 6/23/04 10:30 AM 1,2-Dichloropropane (R)

10 6/17/04 10:45 AM 1,2-Dichloropropane (R) E 0.02519 E 0.005 < 0.029

11 6/22/04 10:30 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

12 6/22/04 1:30 PM 1,2-Dichloropropane (R) < 0.029 < 0.029

14 6/29/04 10:40 AM 1,2-Dichloropropane (R) < 0.029 < 0.029

3 6/18/04 10:15 AM Bromodichloromethane (R) < 0.028 0.2072 0.003

4 7/15/04 11:15 AM Bromodichloromethane (R) E 0.02614 E 0.0003 < 0.028

5 7/30/04 11:40 AM Bromodichloromethane (R)

7 7/23/04 10:00 AM Bromodichloromethane (R) < 0.028 < 0.028

8 7/14/04 10:00 AM Bromodichloromethane (R) < 0.028 < 0.028

9 6/23/04 10:30 AM Bromodichloromethane (R)

10 6/17/04 10:45 AM Bromodichloromethane (R) < 0.028 0.3165 0.004

11 6/22/04 10:30 AM Bromodichloromethane (R) < 0.028 0.4992 0.006

12 6/22/04 1:30 PM Bromodichloromethane (R) < 0.028 E 0.08398 E 0.001

14 6/29/04 10:40 AM Bromodichloromethane (R) < 0.028 0.1907 0.002
26 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM Bromoform (R) < 0.1 0.1174 0.001

4 7/15/04 11:15 AM Bromoform (R) < 0.1 < 0.1

5 7/30/04 11:40 AM Bromoform (R)

7 7/23/04 10:00 AM Bromoform (R) < 0.1 < 0.1

8 7/14/04 10:00 AM Bromoform (R) < 0.1 < 0.1

9 6/23/04 10:30 AM Bromoform (R)

10 6/17/04 10:45 AM Bromoform (R) < 0.1 0.176 0.002

11 6/22/04 10:30 AM Bromoform (R) < 0.1 0.1141 0.001

12 6/22/04 1:30 PM Bromoform (R) < 0.1 < 0.1

14 6/29/04 10:40 AM Bromoform (R) < 0.1 0.2198 0.003

3 6/18/04 10:15 AM Carbon Disulfide (U) E 0.03227 E 0.00005 < 0.038

4 7/15/04 11:15 AM Carbon Disulfide (U) < 0.038 < 0.038

5 7/30/04 11:40 AM Carbon Disulfide (U)

7 7/23/04 10:00 AM Carbon Disulfide (U) < 0.038 < 0.038

8 7/14/04 10:00 AM Carbon Disulfide (U) < 0.038 < 0.038

9 6/23/04 10:30 AM Carbon Disulfide (U)

10 6/17/04 10:45 AM Carbon Disulfide (U) < 0.038 < 0.038

11 6/22/04 10:30 AM Carbon Disulfide (U) < 0.038 < 0.038

12 6/22/04 1:30 PM Carbon Disulfide (U) < 0.038 < 0.038

14 6/29/04 10:40 AM Carbon Disulfide (U) < 0.038 < 0.038

3 6/18/04 10:15 AM Chloroform (R) 0.1829 0.002 0.1745 0.002

4 7/15/04 11:15 AM Chloroform (R) 0.1722 0.002 0.1228 0.002

5 7/30/04 11:40 AM Chloroform (R)

7 7/23/04 10:00 AM Chloroform (R) E 0.0887 E 0.001 E 0.03198 E 0.0004

8 7/14/04 10:00 AM Chloroform (R) E 0.02161 E 0.0003 E 0.08949 E 0.001

9 6/23/04 10:30 AM Chloroform (R)

10 6/17/04 10:45 AM Chloroform (R) 0.1108 0.001 0.114 0.001

11 6/22/04 10:30 AM Chloroform (R) E 0.0476 E 0.0006 0.276 0.003

12 6/22/04 1:30 PM Chloroform (R) 0.2197 0.003 0.2402 0.003

14 6/29/04 10:40 AM Chloroform (R) 0.1461 0.002 0.7157 0.009
Appendix 1 27

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM cis-1,2-Dichloroethene (R) < 0.024 < 0.024

4 7/15/04 11:15 AM cis-1,2-Dichloroethene (R) < 0.024 < 0.024

5 7/30/04 11:40 AM cis-1,2-Dichloroethene (R)

7 7/23/04 10:00 AM cis-1,2-Dichloroethene (R) 0.1585 0.002 E 0.03547 E 0.0005

8 7/14/04 10:00 AM cis-1,2-Dichloroethene (R) < 0.024 < 0.024

9 6/23/04 10:30 AM cis-1,2-Dichloroethene (R)

10 6/17/04 10:45 AM cis-1,2-Dichloroethene (R) < 0.024 < 0.024

11 6/22/04 10:30 AM cis-1,2-Dichloroethene (R) 0.131 0.002 < 0.024

12 6/22/04 1:30 PM cis-1,2-Dichloroethene (R) < 0.024 < 0.024

14 6/29/04 10:40 AM cis-1,2-Dichloroethene (R) E 0.03209 E 0.0005 E 0.02977 E 0.0004

3 6/18/04 10:15 AM Dibromochloromethane (R) < 0.1 0.3691 0.005

4 7/15/04 11:15 AM Dibromochloromethane (R) < 0.1 < 0.1

5 7/30/04 11:40 AM Dibromochloromethane (R)

7 7/23/04 10:00 AM Dibromochloromethane (R) < 0.1 < 0.1

8 7/14/04 10:00 AM Dibromochloromethane (R) < 0.1 < 0.1

9 6/23/04 10:30 AM Dibromochloromethane (R)

10 6/17/04 10:45 AM Dibromochloromethane (R) < 0.1 0.4472 0.006

11 6/22/04 10:30 AM Dibromochloromethane (R) < 0.1 0.5078 0.006

12 6/22/04 1:30 PM Dibromochloromethane (R) < 0.1 0.104 0.001

14 6/29/04 10:40 AM Dibromochloromethane (R) < 0.1 0.4065 0.005

3 6/18/04 10:15 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

4 7/15/04 11:15 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

5 7/30/04 11:40 AM Ethyl tert-butyl ether (ETBE) (U)

7 7/23/04 10:00 AM Ethyl tert-butyl ether (ETBE) (U) 0.2409 0.1452

8 7/14/04 10:00 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

9 6/23/04 10:30 AM Ethyl tert-butyl ether (ETBE) (U)

10 6/17/04 10:45 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

11 6/22/04 10:30 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

12 6/22/04 1:30 PM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05

14 6/29/04 10:40 AM Ethyl tert-butyl ether (ETBE) (U) < 0.05 < 0.05
28 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM m- & p-xylene (U) < 0.06 < 0.06

4 7/15/04 11:15 AM m- & p-xylene (U) < 0.06 < 0.06

5 7/30/04 11:40 AM m- & p-xylene (U)

7 7/23/04 10:00 AM m- & p-xylene (U) < 0.06 < 0.06

8 7/14/04 10:00 AM m- & p-xylene (U) < 0.06 < 0.06

9 6/23/04 10:30 AM m- & p-xylene (U)

10 6/17/04 10:45 AM m- & p-xylene (U) < 0.06 E 0.02209 0.000002

11 6/22/04 10:30 AM m- & p-xylene (U) < 0.06 < 0.06

12 6/22/04 1:30 PM m- & p-xylene (U) < 0.06 < 0.06

14 6/29/04 10:40 AM m- & p-xylene (U) < 0.06 < 0.06

3 6/18/04 10:15 AM Methyl tert-butyl ether (MTBE) (U) < 0.17 < 0.17

4 7/15/04 11:15 AM Methyl tert-butyl ether (MTBE) (U) 0.7355 < 0.17

5 7/30/04 11:40 AM Methyl tert-butyl ether (MTBE) (U)

7 7/23/04 10:00 AM Methyl tert-butyl ether (MTBE) (U) 7.843 6.033

8 7/14/04 10:00 AM Methyl tert-butyl ether (MTBE) (U) < 0.17 < 0.17

9 6/23/04 10:30 AM Methyl tert-butyl ether (MTBE) (U)

10 6/17/04 10:45 AM Methyl tert-butyl ether (MTBE) (U) < 0.17 < 0.17

11 6/22/04 10:30 AM Methyl tert-butyl ether (MTBE) (U) 0.5554 0.3591

12 6/22/04 1:30 PM Methyl tert-butyl ether (MTBE) (U) < 0.17 < 0.17

14 6/29/04 10:40 AM Methyl tert-butyl ether (MTBE) (U) < 0.17 < 0.17

3 6/18/04 10:15 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

4 7/15/04 11:15 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

5 7/30/04 11:40 AM tert-Amyl methyl ether (TAME) (U)

7 7/23/04 10:00 AM tert-Amyl methyl ether (TAME) (U) 0.935 0.6555

8 7/14/04 10:00 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

9 6/23/04 10:30 AM tert-Amyl methyl ether (TAME) (U)

10 6/17/04 10:45 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

11 6/22/04 10:30 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

12 6/22/04 1:30 PM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08

14 6/29/04 10:40 AM tert-Amyl methyl ether (TAME) (U) < 0.08 < 0.08
Appendix 1 29

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM Perchloroethene (PCE) (R) < 0.06 < 0.06

4 7/15/04 11:15 AM Perchloroethene (PCE) (R) E 0.01675 E 0.003 < 0.06

5 7/30/04 11:40 AM Perchloroethene (PCE) (R)

7 7/23/04 10:00 AM Perchloroethene (PCE) (R) 0.5006 0.1 < 0.06

8 7/14/04 10:00 AM Perchloroethene (PCE) (R) < 0.06 E 0.02004 E 0.004

9 6/23/04 10:30 AM Perchloroethene (PCE) (R)

10 6/17/04 10:45 AM Perchloroethene (PCE) (R) 0.3753 0.08 < 0.06

11 6/22/04 10:30 AM Perchloroethene (PCE) (R) 8.016 2 E 0.02187 E 0.004

12 6/22/04 1:30 PM Perchloroethene (PCE) (R) E 0.05175 E 0.01 E 0.04909 E 0.01

14 6/29/04 10:40 AM Perchloroethene (PCE) (R) 0.5595 0.1 0.5422 0.1

3 6/18/04 10:15 AM Toluene (R) < 0.05 < 0.05

4 7/15/04 11:15 AM Toluene (R) < 0.05 < 0.05

5 7/30/04 11:40 AM Toluene (R)

7 7/23/04 10:00 AM Toluene (R) < 0.05 < 0.05

8 7/14/04 10:00 AM Toluene (R) < 0.05 < 0.05

9 6/23/04 10:30 AM Toluene (R)

10 6/17/04 10:45 AM Toluene (R) < 0.05 E 0.03522 E 0.00004

11 6/22/04 10:30 AM Toluene (R) < 0.05 < 0.05

12 6/22/04 1:30 PM Toluene (R) < 0.05 < 0.05

14 6/29/04 10:40 AM Toluene (R) < 0.05 < 0.05

3 6/18/04 10:15 AM Trichloroethene (TCE) (R) < 0.038 < 0.038

4 7/15/04 11:15 AM Trichloroethene (TCE) (R) < 0.038 < 0.038

5 7/30/04 11:40 AM Trichloroethene (TCE) (R)

7 7/23/04 10:00 AM Trichloroethene (TCE) (R) 4.309 0.9 0.2947 0.06

8 7/14/04 10:00 AM Trichloroethene (TCE) (R) < 0.038 < 0.038

9 6/23/04 10:30 AM Trichloroethene (TCE) (R)

10 6/17/04 10:45 AM Trichloroethene (TCE) (R) 0.202 0.04 E 0.09718 E 0.02

11 6/22/04 10:30 AM Trichloroethene (TCE) (R) 0.3634 0.07 < 0.038

12 6/22/04 1:30 PM Trichloroethene (TCE) (R) < 0.038 < 0.038

14 6/29/04 10:40 AM Trichloroethene (TCE) (R) 0.1457 0.03 0.1362 0.03
30 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Volatile organic compounds—Continued

3 6/18/04 10:15 AM Trichlorofluoromethane (U) < 0.16 < 0.16

4 7/15/04 11:15 AM Trichlorofluoromethane (U) E 0.1341 E 0.00007 < 0.16

5 7/30/04 11:40 AM Trichlorofluoromethane (U)

7 7/23/04 10:00 AM Trichlorofluoromethane (U) < 0.16 < 0.16

8 7/14/04 10:00 AM Trichlorofluoromethane (U) < 0.16 < 0.16

9 6/23/04 10:30 AM Trichlorofluoromethane (U)

10 6/17/04 10:45 AM Trichlorofluoromethane (U) < 0.16 < 0.16

11 6/22/04 10:30 AM Trichlorofluoromethane (U) < 0.16 < 0.16

12 6/22/04 1:30 PM Trichlorofluoromethane (U) < 0.16 < 0.16

14 6/29/04 10:40 AM Trichlorofluoromethane (U) < 0.16 < 0.16

Pesticides

3 6/18/04 10:15 AM 2-Hydroxyatrazine (U) < 0.008 < 0.008

4 7/15/04 11:15 AM 2-Hydroxyatrazine (U) < 0.008 < 0.008

5 7/30/04 11:40 AM 2-Hydroxyatrazine (U)

7 7/23/04 10:00 AM 2-Hydroxyatrazine (U) < 0.008 < 0.008

8 7/14/04 10:00 AM 2-Hydroxyatrazine (U) E 0.0084 E 0.0001

9 6/23/04 10:30 AM 2-Hydroxyatrazine (U) < 0.008 E 0.0046 E 0.00007

10 6/17/04 10:45 AM 2-Hydroxyatrazine (U) < 0.008

11 6/22/04 10:30 AM 2-Hydroxyatrazine (U) < 0.008 < 0.008

12 6/22/04 1:30 PM 2-Hydroxyatrazine (U) E 0.0076 E 0.0001 E 0.0061 E 0.00009

14 6/29/04 10:40 AM 2-Hydroxyatrazine (U)

3 6/18/04 10:15 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

4 7/15/04 11:15 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

5 7/30/04 11:40 AM 3,4-Dichloroaniline (U)

7 7/23/04 10:00 AM 3,4-Dichloroaniline (U) < 0.0045 E 0.0029

8 7/14/04 10:00 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

9 6/23/04 10:30 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

10 6/17/04 10:45 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

11 6/22/04 10:30 AM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

12 6/22/04 1:30 PM 3,4-Dichloroaniline (U) < 0.0045 < 0.0045

14 6/29/04 10:40 AM 3,4-Dichloroaniline (U)
Appendix 1 31

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Pesticides—Continued

3 6/18/04 10:15 AM 4-Chloro-2-methylphenol (U) < 0.0056 < 0.0056

4 7/15/04 11:15 AM 4-Chloro-2-methylphenol (U) < 0.0057 E 0.0042

5 7/30/04 11:40 AM 4-Chloro-2-methylphenol (U)

7 7/23/04 10:00 AM 4-Chloro-2-methylphenol (U) < 0.0057 < 0.0057

8 7/14/04 10:00 AM 4-Chloro-2-methylphenol (U) < 0.0057 < 0.0057

9 6/23/04 10:30 AM 4-Chloro-2-methylphenol (U) < 0.0056 < 0.0056

10 6/17/04 10:45 AM 4-Chloro-2-methylphenol (U) < 0.0056 < 0.0056

11 6/22/04 10:30 AM 4-Chloro-2-methylphenol (U) < 0.0056 < 0.0056

12 6/22/04 1:30 PM 4-Chloro-2-methylphenol (U) < 0.0056 < 0.0056

14 6/29/04 10:40 AM 4-Chloro-2-methylphenol (U)

3 6/18/04 10:15 AM Atrazine (R) E 0.0001 E 0.00003 < 0.007

4 7/15/04 11:15 AM Atrazine (R) 0.0112 0.004 0.0305 0.01

5 7/30/04 11:40 AM Atrazine (R)

7 7/23/04 10:00 AM Atrazine (R) < 0.007 < 0.007

8 7/14/04 10:00 AM Atrazine (R) 0.0214 0.007 0.024 0.008

9 6/23/04 10:30 AM Atrazine (R) 0.0154 0.005 0.0156 0.005

10 6/17/04 10:45 AM Atrazine (R) E 0.0062 E 0.002 0.0086 0.003

11 6/22/04 10:30 AM Atrazine (R) E 0.0025 E 0.0008 E 0.0028 E 0.0009

12 6/22/04 1:30 PM Atrazine (R) 0.0183 0.006 0.0191 0.006

14 6/29/04 10:40 AM Atrazine (R)

3 6/18/04 10:15 AM Bentazon (U) < 0.011 < 0.011

4 7/15/04 11:15 AM Bentazon (U) < 0.011 < 0.011

5 7/30/04 11:40 AM Bentazon (U)

7 7/23/04 10:00 AM Bentazon (U) < 0.011 < 0.011

8 7/14/04 10:00 AM Bentazon (U) < 0.011

9 6/23/04 10:30 AM Bentazon (U) < 0.011 < 0.011

10 6/17/04 10:45 AM Bentazon (U) < 0.011

11 6/22/04 10:30 AM Bentazon (U) E 0.0065 E 0.00003 E 0.0065 E 0.00003

12 6/22/04 1:30 PM Bentazon (U) < 0.011 < 0.011

14 6/29/04 10:40 AM Bentazon (U)
32 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Pesticides—Continued

3 6/18/04 10:15 AM Deethylatrazine (U) E 0.0021 E 0.0022

4 7/15/04 11:15 AM Deethylatrazine (U) E 0.007 E 0.0117

5 7/30/04 11:40 AM Deethylatrazine (U)

7 7/23/04 10:00 AM Deethylatrazine (U) < 0.006 < 0.006

8 7/14/04 10:00 AM Deethylatrazine (U) E 0.0159 E 0.0186

9 6/23/04 10:30 AM Deethylatrazine (U) E 0.0097 E 0.0088

10 6/17/04 10:45 AM Deethylatrazine (U) E 0.006 E 0.0077

11 6/22/04 10:30 AM Deethylatrazine (U) E 0.0019 E 0.0017

12 6/22/04 1:30 PM Deethylatrazine (U) E 0.0024 E 0.0029

14 6/29/04 10:40 AM Deethylatrazine (U)

3 6/18/04 10:15 AM Diazinon (U) < 0.005 < 0.005

4 7/15/04 11:15 AM Diazinon (U) 0.0099 0.0052

5 7/30/04 11:40 AM Diazinon (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Diazinon (U) < 0.005 < 0.005

8 7/14/04 10:00 AM Diazinon (U) < 0.005 < 0.005

9 6/23/04 10:30 AM Diazinon (U) < 0.005 < 0.005

10 6/17/04 10:45 AM Diazinon (U) < 0.005 < 0.005

11 6/22/04 10:30 AM Diazinon (U) < 0.005 < 0.005

12 6/22/04 1:30 PM Diazinon (U) < 0.005 < 0.005

14 6/29/04 10:40 AM Diazinon (U) < 0.5 < 0.5

3 6/18/04 10:15 AM Fipronil (U) < 0.016 < 0.016

4 7/15/04 11:15 AM Fipronil (U) E 0.0032 < 0.016

5 7/30/04 11:40 AM Fipronil (U)

7 7/23/04 10:00 AM Fipronil (U) E 0.0056 < 0.016

8 7/14/04 10:00 AM Fipronil (U) < 0.016 < 0.016

9 6/23/04 10:30 AM Fipronil (U) < 0.016 < 0.016

10 6/17/04 10:45 AM Fipronil (U) < 0.016 < 0.016

11 6/22/04 10:30 AM Fipronil (U) < 0.016 < 0.016

12 6/22/04 1:30 PM Fipronil (U) < 0.016 < 0.016

14 6/29/04 10:40 AM Fipronil (U)
Appendix 1 33

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Pesticides—Continued

3 6/18/04 10:15 AM Fipronil sulfide (U) < 0.013 < 0.013

4 7/15/04 11:15 AM Fipronil sulfide (U) < 0.013 < 0.013

5 7/30/04 11:40 AM Fipronil sulfide (U)

7 7/23/04 10:00 AM Fipronil sulfide (U) E 0.0068 E 0.0075

8 7/14/04 10:00 AM Fipronil sulfide (U) < 0.013 < 0.013

9 6/23/04 10:30 AM Fipronil sulfide (U) < 0.013 < 0.013

10 6/17/04 10:45 AM Fipronil sulfide (U) < 0.013 < 0.013

11 6/22/04 10:30 AM Fipronil sulfide (U) < 0.013 < 0.013

12 6/22/04 1:30 PM Fipronil sulfide (U) < 0.013 < 0.013

14 6/29/04 10:40 AM Fipronil sulfide (U)

3 6/18/04 10:15 AM Imidacloprid (U) < 0.0068 < 0.0068

4 7/15/04 11:15 AM Imidacloprid (U) < 0.0132 < 0.0068

5 7/30/04 11:40 AM Imidacloprid (U)

7 7/23/04 10:00 AM Imidacloprid (U) < 0.0068 < 0.0068

8 7/14/04 10:00 AM Imidacloprid (U) < 0.0068

9 6/23/04 10:30 AM Imidacloprid (U) < 0.0068 < 0.0068

10 6/17/04 10:45 AM Imidacloprid (U) < 0.0068

11 6/22/04 10:30 AM Imidacloprid (U) < 0.0068 < 0.0068

12 6/22/04 1:30 PM Imidacloprid (U) E 0.0062 E 0.00002 < 0.0068

14 6/29/04 10:40 AM Imidacloprid (U)

3 6/18/04 10:15 AM Metalaxyl (U) < 0.0051 < 0.0051

4 7/15/04 11:15 AM Metalaxyl (U) 0.0099 0.00002 < 0.02

5 7/30/04 11:40 AM Metalaxyl (U)

7 7/23/04 10:00 AM Metalaxyl (U) < 0.0051 < 0.0051

8 7/14/04 10:00 AM Metalaxyl (U) < 0.0051 < 0.0051

9 6/23/04 10:30 AM Metalaxyl (U) < 0.0051 < 0.0051

10 6/17/04 10:45 AM Metalaxyl (U) < 0.0051 0.071 0.0001

11 6/22/04 10:30 AM Metalaxyl (U) < 0.0051 < 0.0051

12 6/22/04 1:30 PM Metalaxyl (U) < 0.0051 < 0.0051

14 6/29/04 10:40 AM Metalaxyl (U)
34 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Pesticides—Continued

3 6/18/04 10:15 AM Metolachlor (U) < 0.013 < 0.013

4 7/15/04 11:15 AM Metolachlor (U) E 0.0065 E 0.00009 < 0.013

5 7/30/04 11:40 AM Metolachlor (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Metolachlor (U) < 0.013 < 0.013

8 7/14/04 10:00 AM Metolachlor (U) < 0.013 < 0.013

9 6/23/04 10:30 AM Metolachlor (U) < 0.013 < 0.013

10 6/17/04 10:45 AM Metolachlor (U) < 0.013 < 0.013

11 6/22/04 10:30 AM Metolachlor (U) E 0.002 E 0.00003 E 0.0021 E 0.00003

12 6/22/04 1:30 PM Metolachlor (U) < 0.013 < 0.013

14 6/29/04 10:40 AM Metolachlor (U) < 0.5 < 0.5

3 6/18/04 10:15 AM Oryzalin (U) < 0.0176 < 0.0176

4 7/15/04 11:15 AM Oryzalin (U) < 0.0176 E 0.075 E 0.0002

5 7/30/04 11:40 AM Oryzalin (U)

7 7/23/04 10:00 AM Oryzalin (U) < 0.0176 < 0.0176

8 7/14/04 10:00 AM Oryzalin (U) < 0.0176

9 6/23/04 10:30 AM Oryzalin (U) < 0.0176 < 0.0176

10 6/17/04 10:45 AM Oryzalin (U) < 0.0176

11 6/22/04 10:30 AM Oryzalin (U) < 0.0176 < 0.0176

12 6/22/04 1:30 PM Oryzalin (U) < 0.0176 < 0.0176

14 6/29/04 10:40 AM Oryzalin (U)

3 6/18/04 10:15 AM Prometon (U) < 0.005 < 0.005

4 7/15/04 11:15 AM Prometon (U) E 0.0077 E 0.00008 E 0.0081 E 0.00008

5 7/30/04 11:40 AM Prometon (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Prometon (U) < 0.005 < 0.005

8 7/14/04 10:00 AM Prometon (U) < 0.005 < 0.005

9 6/23/04 10:30 AM Prometon (U) 0.0066 0.00007 E 0.0144 E 0.0001

10 6/17/04 10:45 AM Prometon (U) < 0.005 < 0.005

11 6/22/04 10:30 AM Prometon (U) E 0.0023 E 0.00002 E 0.0028 E 0.00003

12 6/22/04 1:30 PM Prometon (U) < 0.005 < 0.005

14 6/29/04 10:40 AM Prometon (U) < 0.5 < 0.5
Appendix 1 35

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Pesticides—Continued

3 6/18/04 10:15 AM Simazine (R) E 0.001 E 0.0003 E 0.0013 E 0.0003

4 7/15/04 11:15 AM Simazine (R) 0.0071 0.002 0.0112 0.003

5 7/30/04 11:40 AM Simazine (R)

7 7/23/04 10:00 AM Simazine (R) 0.0081 0.002 0.0103 0.003

8 7/14/04 10:00 AM Simazine (R) < 0.005 < 0.005

9 6/23/04 10:30 AM Simazine (R) 0.0073 0.002 0.0065 0.002

10 6/17/04 10:45 AM Simazine (R) < 0.005 < 0.005

11 6/22/04 10:30 AM Simazine (R) E 0.0011 E 0.0003 E 0.0014 E 0.0004

12 6/22/04 1:30 PM Simazine (R) E 0.003 E 0.0008 E 0.0032 E 0.0008

14 6/29/04 10:40 AM Simazine (R)

Other anthropogenic organic compounds

3 6/18/04 10:15 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5

4 7/15/04 11:15 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 E 0.088

8 7/14/04 10:00 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 < 0.5

10 6/17/04 10:45 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) < 0.5 E 0.043

12 6/22/04 1:30 PM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U)

14 6/29/04 10:40 AM Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) (U) E 0.081 < 0.5
36 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Other anthropogenic organic compounds—Continued

3 6/18/04 10:15 AM Bisphenol A (U) E 0.13 E 0.0003

4 7/15/04 11:15 AM Bisphenol A (U) E 0.13 E 0.0003 E 0.45 E 0.001

5 7/30/04 11:40 AM Bisphenol A (U) < 1 E 0.2 E 0.0005

7 7/23/04 10:00 AM Bisphenol A (U) < 1 < 1

8 7/14/04 10:00 AM Bisphenol A (U) E 0.12 E 0.0003 E 0.11 E 0.0003

9 6/23/04 10:30 AM Bisphenol A (U) < 1 < 1

10 6/17/04 10:45 AM Bisphenol A (U) < 1 < 1

11 6/22/04 10:30 AM Bisphenol A (U) < 1 < 1

12 6/22/04 1:30 PM Bisphenol A (U)

14 6/29/04 10:40 AM Bisphenol A (U) 2.5 0.006 < 1

3 6/18/04 10:15 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5

4 7/15/04 11:15 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

8 7/14/04 10:00 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

10 6/17/04 10:45 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) < 0.5 < 0.5

12 6/22/04 1:30 PM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U)

14 6/29/04 10:40 AM Hexahydrohexamethylcyclopentabenzopyran 

(HHCB) (U) E 0.079 < 0.5
Appendix 1 37

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Other anthropogenic organic compounds—Continued

3 6/18/04 10:15 AM Methyl salicylate (U) < 0.5

4 7/15/04 11:15 AM Methyl salicylate (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Methyl salicylate (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Methyl salicylate (U) < 0.5 E 0.056

8 7/14/04 10:00 AM Methyl salicylate (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Methyl salicylate (U) < 0.5 < 0.5

10 6/17/04 10:45 AM Methyl salicylate (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Methyl salicylate (U) < 0.5 < 0.5

12 6/22/04 1:30 PM Methyl salicylate (U)

14 6/29/04 10:40 AM Methyl salicylate (U) < 0.5 < 0.5

3 6/18/04 10:15 AM 4-Nonylphenol, diethoxy- (U) < 5

4 7/15/04 11:15 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

5 7/30/04 11:40 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

7 7/23/04 10:00 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

8 7/14/04 10:00 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

9 6/23/04 10:30 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

10 6/17/04 10:45 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

11 6/22/04 10:30 AM 4-Nonylphenol, diethoxy- (U) < 5 < 5

12 6/22/04 1:30 PM 4-Nonylphenol, diethoxy- (U)

14 6/29/04 10:40 AM 4-Nonylphenol, diethoxy- (U) E 3.2 < 5

3 6/18/04 10:15 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5

4 7/15/04 11:15 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 E 0.099

8 7/14/04 10:00 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5
38 Anthropogenic Organic Compounds in Source and Finished Water from Community Wells in Connecticut, 2002–2004

Appendix 1. Concentration and benchmark quotient values for detected anthropogenic organic compounds in samples of source 

water and associated finished water, Connecticut SWQA study.—Continued

[E, estimated value; μg/L, micrograms per liter; <, less than; red type indicates blended water]

E .083 Estimated value

Not analyzed

< 0.5 Blended source

0.0071 Detected value above the reporting limit

0.1 BQ value at or above 0.1

2 BQ value at or above 1

Well 

number 

(see 

fig. 2)

Sample date 

and time Regulated (R) or unregulated (U) compound

Source water Finished water

Concentration

(μg/L)

Benchmark 

quotient

Concentration

(μg/L)

Benchmark 

quotient

Other anthropogenic organic compounds—Continued

10 6/17/04 10:45 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Tri(2-chloroethyl)phosphate (TCEP) (U) < 0.5 < 0.5

12 6/22/04 1:30 PM Tri(2-chloroethyl)phosphate (TCEP) (U)

14 6/29/04 10:40 AM Tri(2-chloroethyl)phosphate (TCEP) (U) E 0.13 < 0.5

3 6/18/04 10:15 AM Tributyl phosphate (U) < 0.5

4 7/15/04 11:15 AM Tributyl phosphate (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Tributyl phosphate (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Tributyl phosphate (U) < 0.5 < 0.5

8 7/14/04 10:00 AM Tributyl phosphate (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Tributyl phosphate (U) < 0.5 < 0.5

10 6/17/04 10:45 AM Tributyl phosphate (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Tributyl phosphate (U) < 0.5 < 0.5

12 6/22/04 1:30 PM Tributyl phosphate (U)

14 6/29/04 10:40 AM Tributyl phosphate (U) E 0.16 < 0.5

3 6/18/04 10:15 AM Triphenyl phosphate (U) < 0.5

4 7/15/04 11:15 AM Triphenyl phosphate (U) < 0.5 < 0.5

5 7/30/04 11:40 AM Triphenyl phosphate (U) < 0.5 < 0.5

7 7/23/04 10:00 AM Triphenyl phosphate (U) < 0.5 < 0.5

8 7/14/04 10:00 AM Triphenyl phosphate (U) < 0.5 < 0.5

9 6/23/04 10:30 AM Triphenyl phosphate (U) < 0.5 < 0.5

10 6/17/04 10:45 AM Triphenyl phosphate (U) < 0.5 < 0.5

11 6/22/04 10:30 AM Triphenyl phosphate (U) < 0.5 < 0.5

12 6/22/04 1:30 PM Triphenyl phosphate (U)

14 6/29/04 10:40 AM Triphenyl phosphate (U) E 0.083 < 0.5