Page 1 U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3076

September 2009 Printed on recycled paper

Figure 1. The Hatfield Reservoir on Running Gutter Brook is located 

in a small, relatively undeveloped watershed in the Connecticut River 

Valley. Most source-water intakes of surface water in the Connecticut, Housatonic, and Thames River Basins (CONN) study unit are 

located on reservoirs or lakes. Although urban and agricultural land 

in the CONN is concentrated along major valleys, the watershed 

for Running Gutter Brook is mostly forested (81 percent), with the 

remaining area agricultural (14 percent), and urban (5 percent). About 

0.24 million gallons per day are taken directly from Running Gutter 

Brook at the community water system to serve the water needs of 

about 3,300 people.

71°

45°

41°

43°

73°

Running Gutter

Brook intake

0

0 50 KILOMETERS

50 MILES

Connecticut

River

Thames

River

Housatonic

River

RHODE

ISLAND

NEW

HAMPSHIRE

MASSACHUSETTS

CONNECTICUT

VERMONT

0

0 50 KILOMETERS

50 MILES

Land-use data 

 (2001 national 

 land cover data)

Public-water supply

 (surface-water)

 intakes

Urban

Forest, shrub

Agricultural

Water, wetlands

EXPLANATION

Other source-

 water intakes

Running Gutter 

 Brook intake

Introduction

An investigation by the National Water-Quality Assessment (NAWQA) Program of the USGS characterizes the 

occurrence of 258 organic compounds in source water (defined 

as stream water collected at a surface-water intake prior to 

water treatment) and finished water (defined as water that has 

passed through treatment processes but prior to distribution) 

from the Hatfield Water Plant, a community water system that 

uses a flow-through reservoir on Running Gutter Brook as its 

primary source of water supply (fig. 1). Running Gutter Brook 

is a first-order tributary to the Connecticut River and drains a 

Prepared as part of the National Water-Quality Assessment Program, Source Water-Quality Assessment

Organic Compounds in Running Gutter Brook Water Used for Public 

Supply near Hatfield, Massachusetts, 2003–05

Connecticut, 

Housatonic, and 

Thames River 

Basins (CONN)

The 258 organic compounds studied in this U.S. Geological 

Survey (USGS) assessment generally are man-made, including 

pesticides, solvents, gasoline hydrocarbons, personal-care and 

domestic-use products, and pavement and combustion-derived 

compounds. Of these 258 compounds, 26 (about 10 percent) 

were detected at least once among the 31 samples collected 

approximately monthly during 2003–05 at the intake of a flowthrough reservoir on Running Gutter Brook in Massachusetts, 

one of several community water systems on tributaries of the 

Connecticut River. About 81 percent of the watershed is forested, 

14 percent is agricultural land, and 5 percent is urban land. In 

most source-water samples collected at Running Gutter Brook, 

fewer compounds were detected and their concentrations were 

low (less than 0.1 microgram per liter) when compared with 

compounds detected at other stream sites across the country that 

drain watersheds that have a larger percentage of agricultural 

and urban areas. The relatively few compounds detected at 

low concentrations reflect the largely undeveloped land use 

at Running Gutter Brook. Despite the absence of wastewater 

discharge points on the stream, however, the compounds 

that were detected could indicate different sources and uses 

(point sources, precipitation, domestic, and agricultural) 

and different pathways to drinking-water supplies (overland 

runoff, groundwater discharge, leaking of treated water from 

distribution lines, and formation during treatment). Six of the 

10 compounds detected most commonly (in at least 20 percent 

of the samples) in source water also were detected commonly 

in finished water (after treatment but prior to distribution). 

Concentrations in source and finished water generally were 

below 0.1 microgram per liter and always less than humanhealth benchmarks, which are available for about one-half of 

the compounds detected. On the basis of this screening-level 

assessment, adverse effects to human health are expected 

to be negligible (subject to limitations of available humanhealth benchmarks).
Page 2

mostly forested watershed that is adjacent to densely populated 

as well as sparsely populated watersheds (Rhodes and others, 

2001). Running Gutter Brook is primarily fed by groundwater 

and by an ephemeral tributary stream, and about 1 square mile of 

the Running Gutter Brook watershed is upstream of the community water system intake. Discharge into the flow-through 

reservoir was measured as being about 1.3 million gallons per 

day or less during baseflow conditions. Samples were collected 

approximately monthly from the reservoir during 2003–05, and 

they included 31 source-water and 14 finished-water samples. 

The samples were analyzed for pesticides and selected pesticide degradates (breakdown products), solvents, gasoline 

hydrocarbons, disinfection by-products (DBPs), personal-care 

and domestic-use products, and other compounds. Community 

water systems are required to monitor finished water for compounds regulated under the Safe Drinking Water Act. Most of the 

compounds included in this study are not regulated under U.S. 

Environmental Protection Agency (USEPA) Federal drinkingwater standards (U.S. Environmental Protection Agency, 2006). 

The Running Gutter Brook study is part of an ongoing NAWQA 

investigation of community water systems across the United 

States. More detailed information and references on the sampling 

design, methodology, specific compounds monitored, and the 

national study are described by Carter and others (2007). Additional USGS information on water quality in the Connecticut, 

Housatonic, and Thames River Basins (CONN) is available for 

the first cycle (1991 to 1995) of the NAWQA study (Garabedian 

and others, 1998).

Occurrence of Organic Compounds in 

Source Water

Recent advances in laboratory analytical methods have 

given scientists the tools to detect a wide variety of contaminants 

in the environment at low concentrations—typically 100 to 

1,000 times lower than drinking-water standards (see inset, 

“What ‘Detections’ May Mean to Human Health”). Twenty-six 

of the compounds were detected in at least one source-water 

sample from Running Gutter Brook (Carter and others, 2007; 

Kingsbury and others, 2008).

Ten compounds were detected in at least 20 percent of 

the source-water samples (defined in this study as “commonly 

detected”; table 1). These included herbicides (atrazine and 

its degradates, and simazine), personal-care and domestic-use 

products (acetyl hexamethyl tetrahydro-naphthalene, or AHTN, 

caffeine, and hexahydrohexa-methylcyclopenta-benzopyran, 

or HHCB), a gasoline hydrocarbon (methyl tert butyl ether, or 

MTBE), and DBPs (chloroform and bromodichloromethane). 

The herbicides atrazine and simazine can be used for weed 

control in agricultural and residential areas in the Running 

Gutter Brook Watershed and across the Nation (Garabedian and 

others, 1998; Gilliom and others, 2006). Atrazine degradates 

including deethylatrazine (DEA) and deisopropyl-atrazine 

(DIA) also were commonly detected. The DBPs chloroform 

and bromodichloromethane were detected commonly in sourcewater samples; chloroform was detected in all of the sourcewater samples and may originate from the leakage of treated 

water from nearby supply lines. Several different personal-care 

and domestic-use products, including fragrances, detergent 

metabolites, and food or beverage ingredients, and other 

compounds, were detected in 47 percent of source-water intake 

samples. Their occurrence may be related to wastewater (Kolpin 

and others, 2002) from domestic septic-tank drainfields that 

leaches to groundwater and then discharges to Running Gutter 

Brook. Only about seven or eight houses are in the drainage 

basin and could contribute wastewater effluent to Running 

Gutter Brook, so the source of these compounds is unknown. 

Overall, the compounds detected most commonly in water from 

Running Gutter Brook are among those most commonly detected 

in ambient stream water across the Nation (Kingsbury and 

others, 2008).

Comparisons Between Source Water and 

Finished Water

Comparisons between source water and finished water are 

not intended to characterize treatment efficacy, but to provide a 

preliminary indication of the potential importance of compounds 

found in source water to the quality of finished water prior to 

distribution (see inset, “Finished-Water Sampling, Water Treatment, and Significance of Comparisons to Source Water”).

Six of the 10 commonly detected compounds in source 

water also were detected commonly in finished water (fig. 2). 

Two groups of compounds in particular, DBPs and herbicides, 

were commonly detected in both source- and finished-water 

What “Detections” May Mean to Human Health

The analytical methods used in this study have low detection 

levels—often 100 to 1,000 times lower than State and Federal 

standards and guidelines for protecting water quality. Detections, 

therefore, do not necessarily indicate a concern to human health 

but rather help to identify the presence of a wide variety of chemicals not commonly monitored in water resources and to track 

changes in their occurrence and concentrations over time. These 

findings complement ongoing drinking-water monitoring required 

by Federal, State, and local programs, which focus primarily on 

post-treatment compliance monitoring of contaminants regulated 

by USEPA in drinking water. Many of the compounds analyzed 

by USGS are not included in other source-water and finishedwater monitoring programs such as the Unregulated Contaminant 

Monitoring Program (U.S. Environmental Protection Agency, 

2007) and the U.S. Department of Agriculture’s Pesticide Data 

Program (U.S. Department of Agriculture, 2008).

Sixty percent of the compounds detected commonly 

in source water also were detected commonly in finished 

water, and generally at similar concentrations, typically 

less than 0.1 microgram per liter.

About one-tenth (26) of the 258 compounds studied 

were detected in at least one source-water sample. These 

compounds represent many different sources and uses 

and include pesticides, solvents, gasoline hydrocarbons, 

and personal-care and domestic-use products. Ten of the 

26 compounds were commonly detected in source-water 

samples; chloroform was detected in all 31 sourcewater samples.
Page 3 

Table 1. A total of 10 of 258 organic compounds were detected commonly (in at least 20 percent of the samples) in 

source water and 8 organic compounds were detected commonly in finished water.

[Bold check marks indicate detections in at least 20 percent of the samples; pesticide degradates are in italics; the levels of detection vary 

between compounds and are listed in Carter and others, 2007]

Compound Detected in 

source water

Detected in 

finished water

Herbicides and herbicide degradates

Atrazine ✔ ✔

Deethylatrazine (DEA) ✔ ✔

Deisopropyl-atrazine (DIA) ✔ ✔

Simazine ✔ ✔

Personal-care and domestic-use products

AHTN (Acetyl hexamethyl tetrahydro-naphthalene) ✔

Caffeine ✔ ✓

HHCB (Hexahydrohexa-methylcyclopenta-benzopyran) ✔ ✓

Gasoline hydrocarbons and additives

MTBE (Methyl tert-butyl ether) ✔

Solvents

1,2-Dichloroethane (ethylene dichloride) ✔

Disinfection by-products

Chloroform ✔ ✔

Bromodichloromethane ✔ ✔

Dibromochloromethane ✔

Finished-Water Sampling, Water Treatment, and Significance of Comparisons to Source Water

Water treatment of the community water system on Running Gutter Brook consists of slow filtration through a silica sand filter and disinfection using chlorine. The silica sand filter consists of a bed of sand that is graded by size, with coarse sand at the intake and fine grains at the 

outlet. Finished-water samples were collected at the community water supply approximately 48 hours after source-water samples to account 

for the retention time of the water in the treatment plant. Some differences between source- and finished-water quality might be attributable 

to changes in source-water quality that are not represented by the finished-water samples because of sample timing and variations in retention 

time, and potential analytic variability associated with low concentrations at or near laboratory reporting levels (Kingsbury and others, 2008). 

It is also possible that some compounds detected in source water were removed or transformed during the treatment process into compounds 

that were not monitored as part of this study. Source water from Running Gutter Brook is occasionally augmented by groundwater from supply 

wells after rainfall-runoff events when the stream is turbid. Groundwater, however, is added to the distribution system after finished water is 

sampled. Therefore, groundwater does not affect the samples of finished water collected for this study.

The study sampling design and resulting comparisons are not intended to characterize treatment efficacy, but to provide a preliminary indication of the potential importance of compounds found in source water to the quality of finished water prior to distribution. In general, the type 

of treatment used at Running Gutter Brook is not specifically designed to remove most of the organic compounds monitored in this study.

samples. Chloroform was detected in all source- and finishedwater samples, although concentrations in source-water samples 

were low, generally at less than 0.1 microgram per liter (tables 1 

and 2; fig. 2). 

Four of the 10 most commonly detected compounds in 

source water, which include MTBE and personal-care products, 

were not detected as commonly, or at all, in finished water. 

The decreased detection of these compounds in finished water 

may be due to reaction with the preservatives (termed “quenching reagents”) used to remove chlorine from samples (Valder 

and others, 2008), or possibly to sorption associated with sand 

filtration or degradation. An herbicide degradate, DIA, also was 

detected more commonly in source water than in finished water, 

and it too may be degraded or transformed during treatment.

Two compounds were detected commonly in finished water 

but not as commonly, or at all, in source water. These include 

a DBP, dibromochloromethane, and a solvent, 1,2-dichloroethane (table 2; fig. 2). The presence of DBPs in finished water is 

well documented, understood, and regulated, and is an expected 

outcome of disinfecting drinking water. The source of the detection of 1,2-dichloroethane is not known, but its occurrence in 

finished water may be a by-product of water treatment.
Page 4

A Closer Look at Organic Compounds in a 

Relatively Undeveloped Watershed

Although Running Gutter Brook had no major wastewater 

input upstream from the sampling point, DBPs and personalcare products were detected commonly in source-water 

samples. Possible sources include chlorinated drinking water 

(for example, from lawn or tree-farm irrigation or leaking 

supply lines), septic systems (Ivahnenko and Zogorski, 2006), 

and also from natural sources such as from the formation of 

chloroform in soils by microbial processes (Laturnus and others, 

2002). Caffeine and fragrance compounds AHTN and HHCB 

were commonly detected; in the absence of major wastewater 

discharges to Running Gutter Brook, septic-tank drainfields 

could be a possible source. An understanding of local hydrology 

and sources of contaminants is needed to fully characterize the 

quality of source water.

Commonly used herbicides and their degradates present 

in Running Gutter Brook could be from applying herbicides to 

agricultural lands, which include an ornamental tree farm and a 

small residential area within the watershed. Concentrations of 

atrazine and other herbicides and their degradates in Running 

Gutter Brook were one or more orders of magnitude less than 

concentrations at the other community water systems sampled 

by the USGS that included more agricultural land use in the 

contributing watersheds (Kingsbury and others, 2008). Transformation can result in the conversion of a parent compound to 

a compound that is commonly less toxic, but some degradates 

have toxicities that are similar to, or greater than, that of their 

parent pesticide (Gilliom and others, 2006). Herbicide degradate 

compounds are not regulated under the Safe Drinking Water Act.

Potential Effects on Human Health

Concentrations of eight compounds that were detected 

in source and (or) finished water (table 1) were greater than 

0.1 microgram per liter (table 2). In general, compounds with 

concentrations greater than 0.1 microgram per liter, such 

as those used in personal-care products (methyl salicylate, 

nonylphenol diethoxylate total (NP2EO), and octylphenol 

monoethoxylate total (OP1EO)), reflect their abundant use in a 

relatively small area of urban land and their physical properties 

that allow them to persist in the environment (Gilliom and 

others, 2006; Zogorski and others, 2006). Concentrations did not 

exceed USEPA drinking-water standards (MCLs) for regulated 

compounds (table 2) in any sample. Concentrations also were 

less than USGS Health-Based Screening Levels (HBSLs) 

established for selected unregulated compounds (see inset, 

“Human-Health Benchmarks Used in This Assessment”).

An important consideration in assessing potential effects 

for human health is the common occurrence of mixtures of 

organic compounds in source- and in finished-water samples. 

For example, the median number of compounds in source-water 

0.001

0.01

0.1

1

10

100

0.001 0.01 0.1 1 10

CONCENTRATION IN SOURCE WATER,

IN MICROGRAMS PER LITER

CONCENTRATION IN FINISHED WATER, 

IN MICROGRAMS PER LITER

EXPLANATION

Atrazine

Deethylatrazine (DEA)

Deisopropylatrazine (DIA)

Simazine

HERBICIDES

Chloroform

Dibromochloromethane

Bromodichloromethane

DISINFECTION 

BY-PRODUCTS

PERSONAL-CARE 

AND DOMESTICUSE PRODUCTS

AHTN

Caffeine

HHCB

OTHER 

ORGANIC 

COMPOUNDS

MTBE

1,2-Dichloroethane

1:1 line

 Figure 2. Six of the 10 compounds detected commonly in source water also were detected commonly in finished 

water for paired samples. Some compounds detected commonly in source water were not detected in finished water 

(x-axis). Other compounds were detected only in finished water (y-axis).

Concentrations for all detected compounds in source 

and finished water generally were less than 0.1 microgram per liter and were always less than human-health 

benchmarks, which are available for about one-half of all 

compounds detected. On the basis of this screening-level 

assessment, adverse effects to human health are expected 

to be negligible (subject to limitations of available benchmarks, see inset “Human-Health Benchmarks Used in 

This Assessment”).
Page 5 

samples at Running Gutter Brook was 5. This is comparable 

to findings at community water systems on streams sampled 

by the USGS that drain relatively undeveloped watersheds 

(Kingsbury and others, 2008). Continued research is needed 

because human-health benchmarks are based on toxicity data for 

individual compounds, and the effects of mixtures of compounds 

at low concentrations are not well understood (Gilliom and 

others, 2006). 

Human-Health Benchmarks Used in 

This Assessment

A screening-level assessment of the potential significance 

of detected compounds to human health was based on a 

comparison of measured concentrations to available humanhealth benchmarks. Specifically, concentrations of regulated 

compounds were compared to USEPA Maximum Contaminant 

Levels (MCLs), and concentrations of unregulated compounds 

that have USEPA published toxicity information were compared 

to USGS Health-Based Screening Levels (HBSLs), which were 

developed in collaboration with USEPA, New Jersey Department 

of Environmental Protection, and Oregon Health & Science 

University (Toccalino and others, 2007). About one-half of 

detected compounds do not have human-health benchmarks or 

adequate toxicity information for evaluating results in a humanhealth context. Human-health benchmarks are developed for 

individual compounds and not mixtures. The screening-level 

assessment provides an initial perspective on the potential 

importance of “man-made” organic compounds in source 

water; it is not a substitute for a comprehensive risk assessment, 

which includes many more factors, such as additional avenues 

of exposure.

Running Gutter Brook Findings in a National 

Context and Possible Implications

Many of the compounds detected most commonly in water 

from Running Gutter Brook (tables 1 and 2) are among those 

most commonly detected in ambient stream water and groundwater across the Nation (Gilliom and others, 2006; Zogorski and 

others, 2006). In addition, the occurrence and concentrations of 

compounds in source and finished water sampled from Running 

Gutter Brook were similar to those detected at other community 

water systems sampled for the USGS national investigation 

of rivers that do not receive any major upstream wastewater 

discharge and that drain relatively small areas of agricultural 

and urban land (Kingsbury and others, 2008). Findings in a 

national context, however, are considered preliminary because 

some compounds included in this study have only recently been 

monitored systematically in source and in finished water, including, for example, plant- or animal-derived biochemicals (such as 

cholesterol) and those used for personal-care, including AHTN, 

HHCB, caffeine, camphor, indole, methyl salicylate, menthol, 

NP2EO, OP2EO, and OP1EO. Continued research is needed to 

better understand sources, transport mechanisms, trends, fate in 

the environment, and possible linkages of these compounds to 

human health.

USGS will continue to collaborate with, and complement 

the work of, other Federal, State, and local organizations, and 

continue to communicate findings and possible implications and 

future needs, including, for example: 

•	 Increased emphasis on watershed management and sourcewater protection strategies to help minimize the sources and 

transport of compounds to source water and ultimately to 

finished water.

Table 2. Only 8 organic compounds that were detected in source and (or) finished water had concentrations greater than 0.1 microgram 

per liter. None of these concentrations exceeded a human-health benchmark; however, benchmarks are available for only 4 of 

the 8 compounds shown in this table.

[μg/L, micrograms per liter; MCL, Maximum Contaminant Level; HBSL, Health-Based Screening Level; --, no data; E, estimated; ND, not detected]

Compound

Number of samples Percent occurrence1 Reporting 

level 

(μg/L)

MCL or 

HBSL 

(μg/L)

Maximum concentration 

(μg/L)

Source 

water

Finished 

water

Source 

water

Finished 

water

Source 

water

Finished 

water

Personal-care and domestic-use products

Methyl salicylate 27 11 3.7 0 0.5 4,000 E0.13 ND

NP2EO (Nonylphenol diethoxylate, total) 27 11 7.4 0 5 -- E2.2 ND

OP2EO (Octylphenol diethoxylate, total) 27 11 7.4 0 1 -- E0.25 ND

OP1EO (Octylphenol monoethoxylate, total) 27 11 7.4 0 1 -- E0.69 ND

Plant- or animal-derived biochemicals

Cholesterol 27 11 3.7 9.1 2 -- E0.19 E0.4

Disinfection by-products

Chloroform 25 9 100 100 0.24

80 total 

THMs2

1.5 19

Bromodichloromethane 25 9 20 100 0.048 0.13 4.9

Dibromochloromethane 25 9 0 100 0.18 ND 0.42

1

Percent occurrence of samples with concentrations equal to or greater than 0.1 μg/L; estimated concentrations are used for compounds that have reporting level 

greater than 0.1 μg/L.

2

MCL of 80 is for total trihalomethanes (THMs), including chloroform, bromoform, bromodichloromethane, and dibromochloromethane.
Page 6

•	 Continued research to enhance toxicity information for commonly occurring unregulated compounds and mixtures that 

are detected commonly in source water and finished water.

•	 Current and future monitoring and assessment to identify 

compounds not typically monitored in source water, but 

commonly present in finished water, which may ultimately 

identify or lead to the development of treatment technologies 

for their removal. 

References Cited

Carter, J.M., Delzer, G.C., Kingsbury, J.A., and Hopple, J.A., 2007, Concentration data for anthropogenic organic compounds in ground water, surface 

water, and finished water of selected community water systems in the 

United States, 2002–05: U.S. Geological Survey Data Series 268, 30 p., 

available at http://pubs.usgs.gov/ds/2007/268.

Delzer, G.C., and Hamilton, P.A., 2007, National Water-Quality Assessment 

Program—Source Water-Quality Assessments: U.S. Geological Survey 

Fact Sheet 2007–3069, 2 p., available at http://pubs.er.usgs.gov/usgspubs/fs/

fs20073069. 

Garabedian, S.P., Coles, J.F., Grady, S.J., Trench, E.C.T., and 

Zimmerman, M.J., 1998, Water-quality assessment of the Connecticut, 

Housatonic, and Thames River Basins, 1991–95: U.S. Geological Survey 

Circular 1155, 32 p., available at http://pubs.usgs.gov/circ/circ1155/. 

Gilliom, R.J., Barbash, J.E., Crawford, C.G., Hamilton, P.A., Martin, J.D., 

Nakagaki, Naomi, Nowell, L.H., Scott, J.C., Stackelberg, P.E., Thelin, G.P., 

and Wolock, D.M., 2006, The quality of our Nation’s waters—Pesticides 

in the Nation’s streams and ground water, 1992–2001: U.S. Geological 

Survey Circular 1291, 172 p., available at http://pubs.er.usgs.gov/usgspubs/

cir/cir1291.

Ivahnenko, Tamara, and Zogorski, J.S., 2006, Sources and occurrence of 

chloroform and other trihalomethanes in drinking-water supply wells in the 

United States, 1986–2001: U.S. Geological Survey Scientific Investigations 

Report 2006–5015, 13 p.

Kingsbury, J.A., Delzer, G.C., and Hopple, J.A., 2008, Anthropogenic organic 

compounds in source water of nine community water systems that withdraw 

from streams, 2002–05: U.S. Geological Survey Scientific Investigations 

Report 2008–5208, 99 p., available at http://pubs.usgs.gov/sir/2008/5208/.

Kolpin, D.W., Furlong, E.T., Meyer, M.T., Thurman, E.M., Zaugg, S.D., 

Barber, L.B., and Buxton, H.T., 2002, Pharmaceuticals, hormones, and other 

organic wastewater contaminants in U.S. streams, 1999–2000—A national 

reconnaissance: Environmental Science and Technology, v. 36, no. 6, 

p. 1202–1211. 

Source Water Quality Assessments by the NAWQA 

Program Conducted Across the Nation 

Beginning in 2002, NAWQA initiated “Source Water-Quality 

Assessments” (SWQAs) at selected community water systems 

across the United States (Delzer and Hamilton, 2007). The longterm goal is to complete as many as 30 SWQAs at systems that 

withdraw water from streams by 2012 using standard protocols 

and nationally consistent methods (U.S. Geological Survey, 

1997–2006). 

This fact sheet highlights findings from the Running Gutter 

Brook study, which is one of the first nine community water 

systems sampled. The fact sheet serves as a companion product to 

a USGS Scientific Investigations Report and Data Series Report 

that present findings for the nine systems across the United 

States (Carter and others, 2007; Kingsbury and others, 2008). 

http://water.usgs.gov/nawqa/swqa/.

Additional information on Running Gutter Brook Watershed 

Water-Quality Assessment is available on the World Wide Web at 

http://ct.water.usgs.gov/nawqa/. 

Laturnus, Frank, Haselmann, K.F., Borch, Thomas, and Gron, Christian, 2002, 

Terrestrial natural sources of trichloromethane (chloroform, CHCl3)—An 

overview: Biochemistry, v. 60, p. 121–139.

Rhodes, A.L., Newton, R.M., and Pufall, Ann, 2001, Influences of land use on 

water quality of a diverse New England watershed: Environmental Science 

and Technology, v. 35, no. 18, p. 3640–3645.

Toccalino, P.L., Norman, J.E., Booth, N.L., and Zogorski, J.S., 2007, HealthBased Screening Levels—A tool for evaluating what water-quality data may 

mean to human health: U.S. Geological Survey, National Water-Quality 

Assessment Program, accessed June 5, 2008, at http://water.usgs.gov/

nawqa/HBSL/. 

U.S. Department of Agriculture, 2008, Agricultural Research Service (ARS), 

Pesticide properties database, accessed March 6, 2008, at http://www.ams.

usda.gov/science/pdp/.

U.S. Environmental Protection Agency, 2006, Setting standards for safe 

drinking water: U.S. Environmental Protection Agency, Office of Ground 

Water and Drinking Water, accessed June 1, 2007, at http://www.epa.gov/

safewater/standard/setting.html.

U.S. Environmental Protection Agency, 2007, Unregulated Contaminant 

Monitoring Program, accessed June 10, 2008, at http://www.epa.gov/

safewater/ucmr/index.html. 

U.S. Geological Survey, 1997–2006, National field manual for the collection of 

water-quality data: U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 9, chaps. A1–A9, available at http://water.usgs.gov/

owq/FieldManual/ (chapters were originally published during 1997–1999; 

updates and revisions are ongoing and are summarized at http://water.usgs.

gov/owq/FieldManual/mastererrata.html.

Valder, J.F., Delzer, G.C., Price, C.V., and Sandstrom, M.W., 2008, Study 

design and percent recoveries of anthropogenic organic compounds with 

and without the addition of ascorbic acid to preserve water samples containing free chlorine, 2004–2006: U.S. Geological Survey Open-File Report 

2008–1226, 86 p., available at http://pubs.usgs.gov/of/2008/1226/.

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., available at http://pubs.er.usgs.gov/usgspubs/cir/cir1292.

By Craig J. Brown and Thomas J. Trombley

For additional information contact 

Craig Brown, U.S. Geological Survey, (860) 291-6766, 

cjbrown@usgs.gov

Greg Delzer, U.S. Geological Survey, SWQA Coordinator, 

(605) 394-3230, gcdelzer@usgs.gov

USGS Promotes Public Access to 

Water-Quality Information

This fact sheet, the USGS national data and investigations 

reports, and other information are available on the World Wide 

Web at http://water.usgs.gov/nawqa/swqa. Included at this Web 

site are downloadable data on organic compound occurrence, 

information on sampling designs and methodology, background 

on data analyses, and frequently asked questions.