science for a changing world

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

Selection Procedure and Salient Information 

for Volatile Organic Compounds Emphasized 

in the National Water-Quality Assessment 

Program

Open-File Report 99-182

National Water-Quality Assessment Study Unit

U.S. Department of the Interior 

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

U.S. Geological Survey

Selection Procedure and Salient Information for 

Volatile Organic Compounds Emphasized in the 

National Water-Quality Assessment Program

By David A. Bender, John S. Zogorski, Michael J. Halde, and Barbara L Rowe

Open-File Report 99-182
U.S. Department of the Interior

Bruce Babbitt, Secretary

U.S. Geological Survey

Charles G. Groat, Director

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

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

Rapid City, South Dakota: 1999

For additional information write to:

District Chief 

U.S. Geological Survey 

1608 Mt. View Road 

Rapid City, SD 57702

Copies of this report can be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
~OREWORD

The mission of the U.S. Geological Survey 

i'USGS) is to assess the quantity and quality of the 

earth resources of the Nation and to provide information that will assist resource managers and policymakers at Federal, State, and local levels in making 

^ound decisions. Assessment of water-quality condi- 

"; ons and trends is an important part of this overall 

mission.

One of the greatest challenges faced by water- 

-esources scientists is acquiring reliable information 

"hat will guide the use and protection of the Nation's 

vater resources. That challenge is being addressed by 

federal, State, interstate, and local water-resource 

agencies and by many academic institutions. These 

organizations are collecting water-quality data for a 

v ost of purposes that include: compliance with permits 

and water-supply standards; development of remedia- 

"; on plans for a specific contamination problem; operational decisions on industrial, wastewater, or water- 

^upply facilities; and research on factors that affect 

vater quality. An additional need for water-quality 

:nformation is to provide a basis on which regional 

and national-level policy decisions can be based. Wise 

decisions must be based on sound information. As a 

"ociety we need to know whether certain types of 

Tater-quality problems are isolated or ubiquitous, 

vhether there are significant differences in conditions 

among regions, whether the conditions are changing 

over time, and why these conditions change from 

olace to place and over time. The information can be 

^sed to help determine the efficacy of existing waterduality policies and to help analysts determine the 

need for and likely consequences of new policies.

To address these needs, the Congress appropriated funds in 1986 for the USGS to begin a pilot 

orogram in seven project areas to develop and refine 

die National Water-Quality Assessment (NAWQA) 

^rogram. In 1991, the USGS began full implementa- 

'ion of the program. The NAWQA Program builds 

upon an existing base of water-quality studies of the 

" JSGS, as well as those of other Federal, State, and 

local agencies. The objectives of the NAWQA 

Program are to:

 Describe current water-quality conditions for a 

large part of the Nation's freshwater streams, rivers, 

and aquifers.

Describe how water quality is changing ove'

time.

 Improve understanding of the primary natural 

and human factors that affect water-quality conditions.

This information will help support the development and evaluation of management, regulatory, and 

monitoring decisions by other Federal, State, and local 

agencies to protect, use, and enhance water resources.

The goals of the NAWQA Program are being 

achieved through ongoing and proposed investigations 

of 59 of the Nation's most important river basins and 

aquifer systems, which are referred to as Study Units. 

These Study Units are distributed throughout the 

Nation and cover a diversity of hydrogeologic 

settings. More than two-thirds of the Nation's freshwater use occurs within the 59 Study Units and more 

than two-thirds of the people served by public watersupply systems live within their boundaries.

National synthesis of data analysis, based on 

aggregation of comparable information obtained from 

the Study Units, is a major component of the program. 

This effort focuses on selected water-quality topics 

using nationally consistent information. Comparative 

studies will explain differences and similarities in 

observed water-quality conditions among study areas 

and will identify changes and trends and their causes. 

The first topics addressed by the national synthesis are 

pesticides, nutrients, volatile organic compounds, and 

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

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

as the information becomes available.

This report is an element of the comprehensive 

body of information developed as part of the NAWC A 

Program. The program depends heavily on the advice, 

cooperation, and information from many Federal, 

State, interstate, Tribal, and local agencies and the 

public. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch 

Chief Hydrologist

Foreword III
vONTENTS

Absttact..............................................................^ 1

''itroduction ................................................................................................................................................................^ 1

Background.................................................................................................................................................................. 2

Selection of volatile organic compounds for emphasis............................................................................................... 2

Purpose and scope....................................................................................................................................................... 3

Acknowledgments................................................................................................._^ 3

/"election procedure for volatile organic compound target analytes...................................................................................... 4

Identification and initial screening of candidate target analytes.................................................................................. 5

Laboratory performance studies.................................................................................................................................. 8

Water-sample validation.............................................................................................................................................. 9

List of target analytes................................................................................................................................................... 9

Salient information for target analytes .................................................................................................................................. 12

Human-health and aesthetic concerns and drinking-water regulations....................................................................... 12

Aquatic toxicity and water-quality guidelines............................................................................................................. 16

Physical, chemical, and biological properties ............................................................................................................. 22

References cited..................................................................................................................................................................... 22

Appendixes .................................................................................................................^ 25

1. Volatile organic compounds (VOCs) considered as candidate target analytes and results of

Phase 1 of screening procedure..................................................................................................................... 26

2. Definitions for physical, chemical, and biological properties................................................................................ 32

LLUSTRATIONS

1. Schematic of the three-phase process used to select volatile organic compounds for emphasis

in the National Water-Quality Assessment Program.................................................................................................. 4

2. Schematic of six-step process used in Phase 1 to screen 130 candidate target analytes on the

basis of available information..................................................................................................................................... 6

"ABLES

1. Physical properties of volatile organic compounds................................................................................................. 7

2. Evaluation of analysis of 16 volatile organic compound candidate target analytes by purge-and-trap

gas chromatography/mass spectrometry on the basis of laboratory performance studies ...................................... 8

3. Volatile organic compound target analytes ............................................................................................................. 10

4. Human-health and aesthetic concerns, and drinking-water regulations, goals, and advisories

for NAWQA volatile organic compound target analytes........................................................................................ 13

5. Lowest concentrations of volatile organic compound target analytes that affect the most sensitive

aquatic species, and water-quality guidelines......................................................................................................... 17

Contents
ABBREVIATIONS AND ACRONYMS

Listed below are abbreviations and acronyms that are used frequently in this report:

AQUIRE AQUatic toxicity Information REtrieval The U.S. Environmental Protection Agency's data base for 

aquatic toxicity; effect concentrations that follow designate the least-to-most sensitive toxic effects on 

aquatic organisms observed during testing:

LC50 Median lethal concentration (50 percent mortality)

EC50 Median effective concentration (affects 50 percent of species with an endpoint other than 

mortality)

LOEC Lowest observed effective concentration (lowest concentration producing an effect)

LOEL Lowest observed effective level

MATC Maximum acceptable toxicant concentration (hypothetical mean between NOEC and LOEC)

NOEC No-observed effective concentration (highest concentration at which observed effects are not 

significant)

CAS Chemical Abstract Service

CWQC Chronic water-quality criteria established by the USEPA

DWEL Drinking-water equivalent level (USEPA Drinking Water Health Advisories)

IRIS Integrated Risk Information System, USEPA's data base for risk assessment and risk management 

information

IUPAC International Union of Pure and Applied Chemistry

MCL Maximum contaminant level

MCLG Maximum contaminant level goal

NAWQA U.S. Geological Survey National Water-Quality Assessment Program

NWQL U.S. Geological Survey National Water-Quality Laboratory

P&T GC/MS Purge-and-trap gas chromatography/mass spectrometry

|0,g/L Microgram per liter

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

VOC Volatile organic compound

VI Contents
Selection Procedure and Salient Information for 

Volatile Organic Compounds Emphasized in the 

National Water-Quality Assessment Program

By David A. Bender, John S. Zogorski, Michael J. Halde, and Barbara L. Rowe

ABSTRACT

Volatile organic compounds (VOCs) are 

organic compounds with chemical and physical 

properties that allow the compounds to move 

freely between water and air. Many products contain VOCs including fuels, solvents, paints, glues, 

adhesives, deodorizers, refrigerants, and fumigants. Because of human-health concerns, many 

VOCs have been the focus of national regulations, 

monitoring, and research during the past 10 to 

20 years.

The selection procedure for VOC target 

analytes for emphasis in the U.S. Geological 

Survey's National Water-Quality Assessment 

(NAWQA) Program, completed in 1994-96, 

involved three sequential phases: (1) initial selection and preliminary screening of 130 candidate 

compounds on the basis of available information; 

(2) laboratory studies to ascertain the feasibility of 

analysis by purge-and-trap gas chromatography/ 

mass spectrometry; and (3) analysis of groundTvater, surface-water, and quality-control samples 

to ascertain the performance of laboratory 

methods on environmental samples. Preliminary 

screening considered several factors including: 

(1) physical properties; (2) human cancer rating; 

(3) noncancer human-health risk; (4) toxicity to 

freshwater aquatic organisms; (5) occurrence data 

for VOCs in ground water, surface water, and 

drinking water; (6) potential for atmospheric 

ozone depletion; (7) bioconcentration in aquatic

organisms; and (8) use or potential use as a fuel 

oxygenate in gasoline. As a result of the selection 

procedure, 55 VOC target analytes were identified 

for additional study including 21 halogenated 

alkanes, 10 halogenated alkenes, 3 aromatic 

hydrocarbons, 9 alkyl benzenes, 6 halogenated 

aromatics, 4 ethers, 1 aldehyde, and 1 nitrile.

Of the 55 VOC target analytes, 29 have a 

national enforceable drinking-water regulation; 

28 are classified as known, probable, or possible 

human carcinogens; 35 have noncancer humanhealth effects; and 33 are known to impart taste 

and odor to water. For the protection of freshwater 

biota, 33 of the 55 VOC target analytes have 

water-quality guidelines established by the U.S. 

Environmental Protection Agency, and 17 have 

water-quality guidelines established by Environment Canada.

Important physical, chemical, and biological properties governing aquatic behavior and fate 

of the VOC target analytes include: aqueous sc Nubility, vapor pressure, Henry's law constant, 

octanol-water partitioning coefficient, sorption 

coefficient, half-life, and bioconcentration factor.

This report (1) describes the step-by-step 

procedure used to select NAWQA's VOC targe* 

analytes, (2) lists the VOC target analytes, and 

(3) provides human-health criteria, drinking-water 

regulations, aquatic toxicity criteria, and other 

information on each target analyte.

Abstract 1
INTRODUCTION 

Background

Volatile organic compounds (VOCs) are organic 

compounds with chemical and physical properties that 

allow the compounds to move freely between water 

and air. In general, these compounds have low molecular weights, high vapor pressures, and low-to-medium 

water solubilities (Rathbun, 1998). VOCs have been 

used extensively in industry, commerce, and households in the United States since the 1940's. Many 

products contain these compounds including, for 

example, fuels, solvents, paints, glues, adhesives, 

deodorizers, refrigerants, and fumigants.

Large quantities of VOCs are released to the 

environment as indicated by reports completed by 

commercial and industrial entities as part of the 1996 

Toxics Release Inventory (U.S. Environmental 

Protection Agency, 1998). Data in this inventory show 

that 10 of the top 20 chemical compounds with the 

largest releases to the environment were VOCs, with 

combined VOC releases of almost 1 trillion pounds in 

1996.

Many VOCs are toxic, and these compounds 

became a focus of a number of Federal regulations 

related to water quality starting in the 1970's (Leahy 

and Thompson, 1994; Pankow and Cherry, 1996). As 

many as 400 VOCs appear on regulatory lists associated with Federal acts (for example, Safe-Drinking 

Water Act, Clean Water Act, Resource Conservation 

and Recovery Act, Clean Air Act, and Food Quality 

Protection Act).

VOCs and various pesticides are compounds of 

primary concern in surface and ground waters, and as 

such, both VOCs and pesticides were included in pilot 

studies of the U.S. Geological Survey's (USGS) 

National Water-Quality Assessment (NAWQA) 

Program (Hirsch and others, 1988) and in the full-scale 

NAWQA Program (Leahy and Thompson, 1994). A 

total of 60 VOCs (prior to NAWQA VOC target analyte selection) were analyzed in NAWQA's groundwater studies between 1993 and 1995, and a total of 88 

VOCs (55 NAWQA VOC target analytes plus 33 additional VOCs) were analyzed in NAWQA's groundwater and surface-water studies completed in 1996-98.

The objectives of the NAWQA Program are to:

(1) describe current water-quality conditions for a large 

part of the water resources of the United States;

(2) define long-term trends or the absence of trends in

water quality; and (3) identify and describe the primary 

factors affecting the observed water-quality conditions 

and trends (Hirsch and others, 1988). The NAWQA 

Program consists of two parts that incHde: (1) investigations of the water quality of river basins and aquifer 

systems; and (2) national synthesis assessments (Leahy 

and Thompson, 1994). The synthesis assessments 

focus on high-priority water-quality issues.

Initial national synthesis assessments described 

the occurrence of nutrients and pesticides in surface 

water and ground water. In 1994, a nrfional study on 

VOCs was initiated because of the widespread occurrence of these compounds in water and the lack of 

information on factors related to their occurrence and 

behavior. The objectives of the VOC national synthesis are to: (1) determine the occurrence of VOCs in 

ground water and surface water, (2) identify probable 

sources of VOCs, and (3) describe the primary processes affecting the concentrations of VOCs in water 

resources of the United States. Within the national 

context, the VOC synthesis seeks to greatly expand 

knowledge concerning the significance of VOCs in 

ambient ground water and in surface water in relation 

to public health and aquatic toxicity. Determining the 

occurrence of VOCs in shallow ground water for 

selected subcategories of land use and defining natural 

and human factors that relate to VOC occurrence are 

planned, as well.

Selection of Volatile Organic Compounds 

for Emphasis

As part of planning NAWQA's national VOC 

synthesis, a subset of VOCs were selected for 

emphasis. Denoted as NAWQA VOC target analytes, 

these compounds are referred to hereir as "VOC target 

analytes." The VOC target analytes are included on 

analytical schedules used in the NAWQA Program. 

Selection of VOC target analytes was done in 1994-96 

utilizing three sequential phases: (1) iritial selection of 

candidate analytes and preliminary screening on the 

basis of published and additional information; 

(2) laboratory studies to ascertain the feasibility of 

analysis by purge-and-trap gas chrom^tography/mass 

spectrometry (P&T GC/MS); and (3) analysis of 

ground water, surface water, and quality-control 

samples to ascertain the performance of field and 

laboratory methods on environmental samples.

Initial selection of candidate VOC target 

analytes was done in 1994 with emphasis on regulated

2 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
VOCs and on VOCs with potential regulation under the 

Safe Drinking Water Act and Clean Water Act. This 

was done because of the water-quality focus of regulations developed under these two acts and because of the 

direct linkage of water-quality data collected in the 

NAWQA Program to these two acts. Consequently, 

VOCs with known or suspected concern to human 

health and (or) aquatic toxicity were emphasized. 

Additional VOCs were considered initially because of 

concern with depletion of the atmosphere's ozone 

level, potential bioconcentration in aquatic organisms, 

or use as oxygenates in gasoline as part of Federally 

mandated programs.

The decision to continue the use of P&T GC/MS 

for analysis of VOCs in water samples collected by the 

NAWQA Program also was made in 1994. The decision to retain P&T GC/MS for the analysis of VOCs 

further reduced the number of candidate VOC target 

analytes. P&T GC/MS has been used extensively in 

the United States for the analysis of VOCs in samples 

of ambient ground water and drinking water since the 

mid-1980's. This methodology has been used since 

1988 at the USGS National Water Quality Laboratory 

(NWQL), which analyzes NAWQA's water samples 

(Rose and Schroeder, 1995). Both unequivocal identification and sub-microgram-per-liter detection levels 

are achieved by the P&T GC/MS method (Connor and 

others, 1998).

Approximately 40 to 60 target analytes were 

sought for emphasis in NAWQA's national assessment 

of VOCs. This number appears reasonable for the 

assessment considering the large number of tasks 

required to assure the completion of the study's overall 

objectives. These tasks include for example: 

(1) implementation of analytical enhancements at the 

NWQL; (2) development and onsite testing of sampling equipment, spiking procedures, and a sample 

preservation method; (3) acquisition and spatial display of information on releases of VOC target analytes 

to the environment; (4) compilation, for each VOC 

target analyte, of physical and chemical properties, 

human-health effects, aquatic toxicity, uses, and 

behavior and fate attributes; and (5) summary of 

information from previous VOC occurrence and distribution studies, and compilation in some cases of the 

actual VOC analytical results.

The list of VOCs given emphasis in the NAWQA 

Program will need periodic updating. This will be 

attempted on about a 10-year cycle and be based on 

information similar to that used to select VOC target 

analytes for emphasis in the first cycle of NAWQA 

studies.

Purpose and Scope

The purposes of this report are to: (1) describe 

the procedure used to select VOC target analytes fcr 

emphasis in the NAWQA Program; (2) list the VOC 

target analytes; and (3) provide salient information on 

each VOC target analyte. As noted previously, the 

selection of VOC target analytes included initial 

screening on the basis of existing information, as well 

as laboratory and field studies for compounds previously not evaluated. Existing information reviewed for 

each candidate analyte included: (1) physical properties; (2) cancer rating; (3) noncancer human-health 

risk; (4) toxicity to aquatic organisms; (5) occurrence 

data for ground water, surface water, and drinking 

water; (6) potential for atmospheric ozone depletion; 

(7) bioconcentration by aquatic organisms; and (8) use 

or potential use as an oxygenate in gasoline. The laboratory study consisted of measuring several solutions 

of each candidate analyte to assess the accuracy and 

precision of analysis by P&T GC/MS. The extent of 

carryover from water samples containing each candidate analyte to laboratory blanks was also assessed in 

the laboratory. Water-sample validation included 

routine processing of ground-water and surface-water 

samples and concurrent analysis of equipment blanks, 

trip blanks, and spiked water samples at the NWQL.

The three-phase selection process resulted in the 

identification of 55 VOC target analytes. Information 

provided for each VOC target analyte includes: 

(1) drinking-water regulations, health advisories, 

cancer rating, risk of noncancer effects, and related 

information; and (2) water-quality guidelines and 

lowest observed toxicity level for aquatic organisms. 

Information sources for physical, chemical, and biological properties that are useful in predicting partitioning among water, air, and soil also are providec1 .

Acknowledgments

The authors thank Jack Barbash, Lisa Nowell, 

Joseph Domagalski, James Ebbert, Dorinda Gellenbeck, Saeid Tadayon, Wayne Lapham, Frank RineFa, 

Paul Gates, Donna Rose, and James Stark of the U.S. 

Geological Survey, for their assistance in developing 

the VOC target analyte list in 1994-96 and for their 

review of the associated selection procedure. The 

authors also thank Paul Stackelberg, Wayne Lapham, 

Lanna Combs, and John Helgesen of the U.S. 

Geological Survey for providing reviews of this report, 

and Ella Decker and Christi Kotschwar of the U.S. 

Geological Survey for publication preparation.

Introduction
SELECTION PROCEDURE FOR VOLATILE 

ORGANIC COMPOUND TARGET 

ANALYTES

The selection procedure for VOC target analytes 

and the final list of VOC target analytes are described 

in this section. The selection procedure involved three 

sequential phases (fig. 1): (1) development of an initial

candidate analyte list and screening of each analyte on 

the basis of existing information; (2) assessment via 

laboratory studies of the feasibility of analysis by P&T 

GC/MS of the VOCs identified in Pha-e 1; and 

(3) water-sample validation of selected analytes by 

analysis of ground-water, surface-water, and qualitycontrol samples using the USGS's analytical method 

for VOCs (Connor and others, 1998).

Phase 1 (1994)

Selection of 130 candidate target

analytes and initial screening on

basis of available information. \Phase 2 (1995)

Laboratory studies completed to

determine the feasibility of

analysis by purge-and-trap gas

chromatography/mass

spectrometry.

Phase 3 (1996)

Analytical performance validated

by processing ground-water,

surface-water, and quality-control

samples.

Figure 1 . Schematic of the three-phase process used to select volatile organic compounds for emphasis in the 

National Water-Quality Assessment Program.

4 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Identification and Initial Screening of 

Candidate Target Analytes

A total of 130 compounds were selected for 

initial screening (fig. 1, appendix 1). One-hundred 

twenty-four (124) compounds were from one or more 

regulatory lists associated with the Safe Drinking 

Water Act and Clean Water Act. Six additional compounds were included on the basis of: (1) listing as a 

carcinogen in the Toxics Release Inventory (chloromethyl methyl ether and &w-(2-chloroethyl) sulfide); 

(2) potential for ozone depletion (1,1,2-trichloro-1,2,2- 

trifluoroethane); or (3) use or potential use as a gasoline 

oxygenate (tert-amyl methyl ether, diisopropyl ether, 

and ethyl tert-bulyl ether).

The 130 candidate analytes (appendix 1) then 

were screened by a six-step process (fig. 2). The first 

step was to determine if the candidate compounds had 

physical properties generally considered typical for 

VOCs. Vapor pressure, aqueous solubility, octanol- 

'vater partition coefficient, Henry's law constant, 

molecular weight, and melting point were the physical 

properties used in this initial screening (table 1). 

Eighty-nine candidate analytes (appendix 1) had 

properties typical of VOCs and were screened further, 

^orty-one compounds failing the physical-properties 

^creen were not classified as volatile and received no 

curther consideration.

The 89 remaining candidate analytes were eval- 

^ated further to determine if they were: (1) a serious 

uman-health concern (fig. 2, steps 2 and 3); (2) toxic 

xo aquatic organisms at low concentrations (fig. 2, 

~tep 4); (3) known to occur frequently in ground water, 

"urface water, or drinking water (fig. 2, step 5); or 

'4) known to be important for other reasons, including 

"he potential for atmospheric ozone depletion, bioaccuTiulation in aquatic organisms, or use as a gasoline 

oxygenate (fig. 2, step 6). Both carcinogenic and noncarcinogenic risks were considered to assess humanv ealth concern. Freshwater, water-quality guidelines, 

and published aquatic toxicity data were used to assess 

aquatic-organism concerns. This additional screening 

-vas done sequentially (fig. 2, steps 2-6). Compounds 

vere retained as VOC target analytes if they met any 

one of the four above-mentioned concerns.

Human carcinogenic potential was assessed 

'fig. 2, step 2) on the basis of the strength of evidence 

^core (U.S. Environmental Protection Agency, 1996a). 

dancer categories and associated criteria are:

A - Human carcinogen sufficient evidence in 

epidemiologic studies to support causal 

association between exposure and cancer; 

B! - Probable human carcinogen limited 

evidence in epidemiological studies; 

62 - Probable human carcinogen sufficient

evidence from animal studies; 

C - Possible human carcinogen limited or 

equivocal evidence from animal studies rnd 

inadequate or no data from human studies; 

D - Not classified inadequate or no human 

and animal evidence of carcinogenicity; 

and 

E - No evidence of carcinogenicity for

humans no evidence of carcinogenicit)' in 

at least two adequate animal tests in different species or in adequate epidemiologic 

and animal studies.

Compounds indicated as either human carcinogens (category A) or probable human carcinogens 

(categories Bj and 62) were considered a serious 

human-health concern and were retained as VOC target 

analytes. Twenty-five compounds passing the physical 

properties screen in appendix 1 are classified by the 

U.S. Environmental Protection Agency (USEPA) as 

either known human carcinogens or probable human 

carcinogens; the remaining 64 compounds that are 

classified are identified as either C or D carcinogens. 

The 25 VOCs with an A, B l5 or B2 classification were 

acrylamide, benzene, bromodichloromethane, bromoethene, chloroethane, chloroethene, &w-(2-chloroethyl) 

ether, few-(2-chloroethyl) sulfide, few-(chloromethyl) 

ether, chloromethyl methyl ether, l,2-dibromo-3-chloropropane, 1,2-dibromoethane, 1,2-dichloroethane, 

dichloromethane, 1,2-dichloropropane, cw-l,3-dichloropropene, brans'-1,3-dichloropropene, 1,4-dioxane, 

formaldehyde, 2-propenenitrile, tetrachloromethane, 

tribromomethane, trichloroethene, trichloromethane, 

and 1,2,3-trichloropropane.

Noncarcinogenic human-health effects (fig. 2, 

step 3) were assessed on the basis of the drinking- waf^r 

equivalent level (DWEL). DWEL is the highest lifetime (70 years) exposure concentration in drinking 

water at which adverse noncarcinogenic health effects 

would not be expected to occur for a person with a 

body weight of 70 kilograms consuming 2 liters of 

water a day (Nowell and Resek, 1994). In the calculation of DWEL, 100-percent exposure to the compound 

is assumed to occur from drinking water. The DWEL 

value for each compound was obtained from the 

USEPA (1996a).

Selection Procedure for Volatile Organic Compound Target Analytes 5
130 candidate target analytes

Stepl

Does candidate analyte have physical 

properties typical of VOCs?

No - 41 candidate analytos not

classified as VOCs. 

Removed from consideration.

Step 2

Yes - 89 compounds classified as VOCs

Is candidate VOC analyte classified 

as a known or potential human carcinogen?

Step 3

and/or does candidate analyte have a drinkingwater equivalent level (DWEL) < 100 u,g/L 

(for example, noncancer effect)?

Step 4

and/or does candidate analyte have a freshwater aquatic toxicity < 100 u,g/L?

StepS

and/or does candidate analyte occur frequently in 

ground water, surface water, or drinking water?

StepS X

and/or does candidate analyte have the potential to

deplete atmospheric ozone, to bioaocumulate in

aquatic organisms, or is it used or potentially used

as a gasoline oxygenate?

X

Yes to any of 

steps 2 - 6

64 candidate analytes ps ssed Phase 1 

screening process and subsequently 

considered in laboratory performance 

and water-sample validation studies.

Figure 2. Schematic of six-step process used in Phase 1 to screen 130 candidate target analytes on the basis of 

available information. [<, less than or equal to; jig/L, microgram per liter]

6 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Table 1 . Physical properties of volatile organic compounds 

(Mackay and Shiu,1990)

[--, dimensionless; >, greater than; <, less than]

Property

Vapor pressure 

Aqueous solubility 

Octanol-water partition

Unit of 

measurement

pascals 

grams per liter

Boundary 

or range1

>500 

10-1,000

coefficient

Henry's law constant 

Molecular weight 

Melting point

grams per mole < 160 

degrees Celsius 25

1 Boundaries of properties apply for most compounds but are not 

totally exclusive.

Experience in the USGS, USEPA, and elsewhere 

indicates that in most natural water (that is, water 

resources not affected by point-source contamination) 

concentrations of VOCs in excess of 100 |Llg/L (micrograms per liter) are rare, and therefore, this concentration represents a conservative exposure threshold. 

Thirteen compounds passing the physical properties 

screen had DWELs of 100 |Llg/L or less (appendix 1), 

five of which were previously selected because of carcinogenic risks. This screening step identified eight 

additional VOC target analytes specifically because of 

the potential for noncarcinogenic health risk in concentration less than or equal to 100 |Hg/L. These eight 

VOCs were bromomethane, chloromethane, hexachlorobutadiene, hexachloroethane, naphthalene, 

pentachlorobenzene, 1,2,4-trichlorobenzene, and 

1,1,2-trichloroethane.

Adverse aquatic-organism effects were assessed 

on the basis of the freshwater, chronic water-quality 

guidelines and aquatic toxicity study results from 

USEPA's AQUIRE data base (fig. 2, step 4). Waterquality guidelines for protection of freshwater biota 

have been published by the USEPA for 36 VOCs. 

These guidelines are based on the lowest observed 

effect level (LOEL). Again, a 100-|Hg/L concentration 

was selected as an appropriate upper threshold for 

selection of the target analyte on the basis of aquatic 

toxicity. Nine compounds that passed the physical 

screen had water-quality guidelines or evidence of 

aquatic toxicity at concentrations of 100 |Hg/L or less, 

three of which were previously selected because of 

noncarcinogenic risks. This screening step identified 

six additional VOC target analytes because of their 

toxicity to aquatic organisms. These six VOCs were

ft-butylbenzene, chlorobenzene, hexachlorocyclopentadiene, 2-propenal, ^o-propylbenzene, and w-propylbenzene.

To assess which VOCs are most frequently 

occurring in ground water, surface water, and drinking 

water, the results of 45 studies were reviewed. Twentyfour of these studies were of regional or national scale. 

Requiring considerable effort, this step was deemed 

especially important to assure that frequently occurring 

compounds were selected as VOC target analytes. 

Results from previous studies by the USEPA Office of 

Ground Water and Drinking Water, the USGS 

NAWQA Program, the USGS Toxics Hydrology 

Program, USGS State programs, and several State 

agency ambient monitoring programs were compiled.

Three criteria for occurrence were used, any one 

providing the basis for selecting a compound for tH 

VOC target analyte list:

1. Compounds were retained if they were detected in at 

least one sample in more than 30 percent of the 45 

studies reviewed. This criterion was the broadest 

assessment of occurrence in that national, 

regional, State, and local studies were included.

2. Compounds were retained if they were detected at 

least once in more than 30 percent of 24 regional 

and national studies. Additionally, these corrpounds must have been target analytes for those 

studies. Finally, it was required that these compounds occurred frequently in the experience of 

the VOC analysis staff at the USGS's NWQL, 

which analyzes approximately 2,500 to 3,OOC 

water samples for VOCs each year (D.L. Rose, 

USGS, oral commun., 1998).

3. Compounds were retained as noted in 2 (above) 

except that when staff at the NWQL did not indicate frequent occurrence, an alternate approach 

was used to confirm the potential for frequen* 

occurrence. Individual studies were examined, 

occurrence data were compiled, and if frequent 

occurrence was indicated in two or more studies, 

the compound was selected as a target analyte.

A total of 20 additional compounds were 

selected as target analytes on the basis of frequency of 

occurrence in past monitoring studies. These compounds were chlorodibromomethane, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzere, 

1,1-dichloroethane, 1,1-dichloroethene, cw-l,2-dichloroethene, fra«^-l,2-dichloroethene, dichlorodifluoromethane, 1,2-dimethylbenzene, 1,3-dimethylbenzene, 1,4-dimethylbenzene, ethylbenzene,

Selection Procedure for Volatile Organic Compound Target Analytes
methylbenzene, methyl tert-butyl ether, styrene, tetrachloroethene, 1,1,1-trichloroethane, trichlorofluoromethane, and 1,2,4-trimethylbenzene.

The final step (fig. 2, step 6) in screening candidate analytes was to review the remaining 30 compounds to assure that target analytes were included for 

three topics of national interest (atmospheric ozone 

depletion, bioaccumulation in aquatic organisms, and 

gasoline oxygenates). Five additional VOCs were 

selected for the target analyte list for these reasons 

(appendix 1). l,l,2-trichloro-l,2,2-trifluoroethanewas 

selected because of its potential for atmospheric-ozone 

depletion, and 1,2,3-trichlorobenzene was selected 

because of its potential for bioaccumulation in aquatic 

organisms. Tert-amyl methyl ether, diisopropyl ether, 

and ethyl tert-butyl ether were selected because of their 

known or potential use as gasoline oxygenates.

Laboratory Performance Studies

Phase 1 of the selection process, just described 

(fig. 2), resulted in selection of 64 candidate VOC target analytes. Forty-eight of these 64 compounds were 

evaluated previously for analytical feasibility by P&T 

GC/MS, and these 48 compounds wer? included on 

NWQL's VOC analysis schedule 209C used in the 

NAWQA Program from 1993 to 1995. Analysis by 

P&T GC/MS of these 48 compounds in ground-water 

and quality-control samples did not indicate any concern about sample stability or adverse matrix effects. 

Therefore, no additional evaluation of these 48 compounds was needed. The remaining 16 candidate VOC 

target analytes (table 2) required further laboratory 

evaluation.

Table 2. Evaluation of analysis of 16 volatile organic compound candidate target analytes by purge-and-trap gas 

chromatography/mass spectrometry on the basis of laboratory performance studies

[IUPAC, International Union of Pure and Applied Chemistry; P&T GC/MS, purge-and-trap gas chromatography/mass spectrometry; \ig/L, micrograms 

per liter]

IUPAC name

bromoethene

2-propenenitrile

hexachloroethane

2-propenal

Feasible to analyze 

by P&T GC/MS

Yes

Yes

Yes

Yes

Performs well.

Performs well.

Performs well.

Remarks

Marginal performance, low precision, and not stable in acidif ?.d samples held

tert-amy\ methyl ether 

diisopropyl ether 

ethyl terf-butyl ether 

acrylamide 

&/j-(2-chloroethyl) ether

fo'j-(2-chloroethyl) sulfide 

few-(chloromethyl) ether 

chloromethyl methyl ether 

1,4-dioxane

formaldehyde 

pentachlorobenzene

hexachlorocyclopentadiene

14 days and longer. 

Yes Performs well. 

Yes Performs well. 

Yes Performs well. 

No Not detectable by P&T GC/MS at levels up to 500 ug/L.

No Poor purging efficiency and low response factor by P&T GC/MS; carryover 

contamination of high-level standards; co-elutes and has a similar ion with 

another compound.

No Not stable for more than 40 minutes in water.

No Not detectable by P&T GC/MS at levels up to 500 ug/L.

No Not detectable by P&T GC/MS at levels up to 500 ug/L.

No Poor purging efficiency and low response factor by P&T GC/MS; carryover 

contamination of high-level standards.

No Not detectable by P&T GC/MS at levels up to 500 ug/L.

No Unacceptable purging efficiency, elution time, and carryover; better analyzed by 

an extraction method.

No Unacceptable purging efficiency, elution time, and carryover; better analyzed by 

an extraction method.

8 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
In 1995, the NWQL completed several laboratory studies to determine the feasibility of measuring 

16 candidate VOC target analytes in water samples by 

P&T GC/MS. These studies assessed purging efficiency, instrument response, precision, carryover, 

analyte stability, and elution time. On the basis of 

results of these studies, 7 of the 16 compounds were 

analyzed adequately using P&T GC/MS. These seven 

compounds were bromoethene, 2-propenenitrile, 

hexachloroethane, 2-propenal, tert-amyl methyl ether, 

diisopropyl ether, and ethyl tert-butyl ether (table 2). 

Although 2-propenal was amenable to analysis by P&T 

GC/MS and retained as a target analyte, analysis of this 

compound was marginal because of lower precision, 

higher detection level, and instability in acidified samples held for 14 days or longer, as compared to the six 

previously noted compounds. Nine of the 16 compounds were not amenable to analysis by P&T GC/MS 

and were not selected as VOC target analytes. The 

"remarks" column of table 2 describes briefly the 

reason why analysis by P&T GC/MS was not feasible. 

The reader is referred to Connor and others (1998) for 

discussion of additional factors that led to deletion of 

these compounds from NWQL's VOC analysis 

schedules. As a result of Phase 2, 55 compounds were 

retained as target analytes.

Water-Sample Validation

To further assess the feasibility of P&T GC/MS 

analysis of the remaining seven candidate VOC target 

analytes (table 2), these compounds were included in 

1996 as analytes on NWQL's VOC custom method 

9090 (along with the other 48 VOC target analytes and 

33 other VOCs). During 1996, the NAWQA Program 

used this method for the analysis of about 1,200 water 

samples including 900 samples of ground water and 

surface water, 200 sample blanks, and 100 matrixspiked samples. This sample validation (Phase 3) confirmed the excellent performance of the P&T GC/MS 

analysis of six analytes previously analyzed in laboratory performance studies (table 2). Water-sample data 

also confirmed the marginal performance of the P&T 

GC/MS in analyzing for 2-propenal, which led to a 

NWQL decision to report all detections of this compound as estimated concentrations. For similar 

reasons, only estimated concentrations are reported for

three other VOC target analytes bromomethane, 

chloromethane, and dichlorodifluoromethane.

In summary, Phase 3 confirmed the analysis 

feasibility of seven candidate VOC target analytes 

including bromoethene, 2-propenenitrile, hexachloroethane, 2-propenal, tert-amyl methyl ether, diisopropyl 

ether, and ethyl tert-butyl ether.

List of Target Analytes

The selection process described heretofore 

resulted in a list of 55 VOCs for emphasis in the 

NAWQA Program. The 55 compounds are listed in 

table 3 by chemical subgroup. The Chemical Abstract 

Services (CAS) numbers and the USGS parameter 

codes are included to assist in compound identification; 

however, the International Union of Pure and App'ied 

Chemistry (IUPAC) name is preferred and is used in 

this report. Many of the VOC target analytes have 

numerous alternative names and abbreviations. Select 

alternative names and abbreviations are given in 

table 3.

Halogenated alkanes frequently are named ir the 

literature as "ethyls" rather than by the IUPAC name. 

For example, ethyl chloride is synonymous with chloroethane. Also, the chlorinated alkenes often appear in 

the literature as "ethylenes" rather than as the current 

IUPAC usage of "ethenes." For example, tetrachloroethylene is the same compound as tetrachloroethene. 

1,3-dimethylbenzene and 1,4-dimethylbenzene (mandp-xylene) have the same USGS parameter code 

because these isomers cannot be separated by the F&T 

GC/MS method. As such, concentrations reportec1 

under this parameter code are the sum for these two 

compound concentrations.

2-propenal is included as a VOC target analyte in 

table 3; however, it was deleted from VOC schedules at 

the NWQL in May 1998 because of erratic and poor 

instrument response after a new concentrator was 

installed. Poor performance is presumed to be associated with a moisture-control system in the new concentrator (D.L. Rose, USGS, oral commun., 1998). 

2-propenal is included in subsequent sections of this 

report and retained as a NAWQA VOC target anah'te 

because 2.5 years of acceptable data were collected by 

the NAWQA Program in 1996-98.

Selection Procedure for Volatile Organic Compound Target Analytes
Table 3. Volatile organic compound target analytes (adapted from Rathbun, 1998)

[CAS, Chemical Abstract Services; USGS, U.S. Geological Survey; IUPAC, International Union of Pure and Applied Chemistry]

IUPAC name

bromodichloromethane

bromomethane 1

chlorodibromomethane

chloroethane

chloromethane 1

1 ,2-dibromo-3-chloropropane

1 ,2-dibromoethane

dichlorodifluoromethane1

1 , 1 -di chloroethane

1 ,2-dichloroethane

dichloromethane

1 ,2-dichloropropane

hexachloroethane

tetrachloromethane

tribromomethane

trichloromethane

1,1,1 -trichloroethane

1 , 1 ,2-trichloroethane

trichlorofluoromethane

1 ,2,3-trichloropropane

1 , 1 ,2-trichloro- 1 ,2,2-trifluoroethane

bromoethene

chloroethene

1 , 1 -dichloroethene

cis- 1 ,2-dichloroethene

trans- 1 ,2-dichloroethene

cis- 1 ,3-dichloropropene

trans- 1 ,3-dichloropropene

hexachlorobutadiene

tetrachloroethene

CAS 

number

75-27-4

74-83-9

124-48-1

75-00-3

74-87-3

96-12-8

106-93-4

75-71-8

75-34-3

107-06-2

75-09-2

78-87-5

67-72-1

56-23-5

75-25-2

67-66-3

71-55-6

79-00-5

75-69-4

96-18-4

76-13-1

593-60-2

75-01-4

75-35-4

156-59-2

156-60-5

10061-01-5

10061-02-6

87-68-3

127-18-4

USGS 

parameter 

code

32101

34413

32105

34311

34418

82625

77651

34668

34496

32103

34423

34541

34396

32102

32104

32106

34506

34511

34488

77443

77652

50002

39175

34501

77093

34546

34704

34699

39702

34475

Select alternative name 

or abbreviation

Halogenated alkanes

~

methyl bromide

~

ethyl chloride

methyl chloride

DBCP

EDB

Freon 12, CFC 12

ethylidenedichloride

ethylenedichloride

methylene chloride

--

--

carbon tetrachloride

bromoform

chloroform

methyl chloroform

-

Freon 11, CFC 11

-

Freon 113, CFC 113

Halogenated alkenes

vinyl bromide

vinyl chloride

-

--

~

~

-

--

tetrachloroethylene,

Predominant 

use

organic synthesis

fumigant

organic synthesis

solvent

refrigerant

fumigant

fumigant

refrigerant

solvent

solvent

solvent

solvent

metallurgy refining

solvent

solvent

solvent

solvent

solvent

refrigerant

solvent

refrigerant

fire retardant

organic synthesis

organic synthesis

solvent

solvent

fumigant

fumigant

organic synthesis

solvent

Chemicri 

formula

CHBrCl2

CH3Br

CHBr2Cl

C2H5C1

CH3C1

C3H5Br2C

C2H4Br2

CC12F2

C2H4C12

C2H4C12

CH2C12

C3H6C12

C2C16

CC14

CHBr3

CHC13

C2H3C13

C2H3C13

CC13F

C3H5C13

C2C13F3

C2H3Br

C2H3C1

C2H2C12

C2H2C12

C2H2C12

C3H4C12

C3H4C12

C4C16

C2C14

Molecular 

weight 

(gram/mole)

163.83

94.94

208.29

64.52

50.49

236.33

187.87

120.91

98.96

98.96

84.93

112.99

236.74

153.82

252.75

119.38

133.41

133.41

137.37

147.43

187.38

106.96

62.50

96.94

96.94

96.94

110.97

110.97

260.76

165.83

trichloroethene 79-01-6 39180

perchloroethylene, PCE 

trichloroethylene, TCE solvent C2HC13 131.39

10 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Table 3. Volatile organic compound target analytes (adapted from Rathbun, 1998) Continued

[CAS, Chemical Abstract Services; USGS, U.S. Geological Survey; IUPAC, International Union of Pure and Applied Chemistry]

IUPAC name

benzene

naphthalene

styrene

n-butylbenzene

1 ,2-dimethylbenzene

1 ,3-di methylbenzene

1 ,4-dimethylbenzene

ethylbenzene

methylbenzene

wo-propylbenzene

n-propylbenzene

1 ,2,4-trimethylbenzene

chlorobenzene

1 ,2-dichlorobenzene

1 ,3-dichlorobenzene

1 ,4-dichlorobenzene

1 ,2,3-trichlorobenzene

1 ,2,4-trichlorobenzene

tert-amyl methyl ether

diisopropyl ether

ethyl tert-butyl ether

methyl terf-butyl ether

CAS 

number

71-43-2

91-20-3

100-42-5

104-51-8

95-47-6

108-38-3

106-42-3

100-41-4

108-88-3

98-82-8

103-65-1

95-63-6

108-90-7

95-50-1

541-73-1

106-46-7

87-61-6

120-82-1

994-05-8

108-20-3

637-92-3

1634-04-4

USGS 

parameter 

code

34030

34696

77128

77342

77135

85795

85795

34371

34010

77223

77224

77222

34301

34536

34566

34571

77613

34551

50005

81577

50004

78032

Select alternative name 

or abbreviation

Aromatic hydrocarbons

~

--

vinyl benzene

Alkyl benzenes

-

o-xylene

m-xylene

p-xylene

~

toluene

cumene

-

--

Halogenated aromatics

-

o-dichlorobenzene

m-dichlorobenzene

p-dichlorobenzene

-

--

Ethers

TAME

DIPE

ETBE

MTBE

Predominant 

use

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

organic synthesis

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

gasoline aromatic 

hydrocarbon

organic synthesis

solvent

organic synthesis

solvent

solvent

solvent

fumigant

organic synthesis

solvent

oxygenate

oxygenate

oxygenate

oxygenate

Chemical 

formula

C6H6

C10H8

QHg

C10H 14

C8H10

C8H10

C8H 10

C8H 10

C7H8

C9H12

C9H12

C9H12

C6H5C1

C6H4C12

C6H4C12

C6H4C12

C6H3C13

C6H3Cl3

C6H140

C6H140

C6H 140

C5H120

Molecular 

weigh* 

(gram/mole)

78.12

128.19

104.16

134.22

106.17

106.17

106.17

106.17

92.15

120.21

120.20

120.21

112.5<i

147.01

147.01

147.01

181.45

181.45

102.18

102.18

102.18

88.15

Others (aldehydes and nitrites)

2-propenal 1 '2

2-propenenitrile

107-02-8

107-13-1

34210

34215

acrolein

acrylonitrile

organic synthesis

organic synthesis

C3H4O

C3H3N

56.0<

53.0<

! A11 detections of these compounds are reported by the National Water Quality Laboratory as estimated concentrations.

2Deleted from list of volatile organic compounds analyzed by the National Water Quality Laboratory in May 1998, because of poor performance after 

installation of new equipment.

Selection Procedure for Volatile Organic Compound Target Analytes 11
The VOC target analyte list includes 21 halogenated alkanes, 10 halogenated alkenes, 3 aromatic 

hydrocarbons, 9 alkyl benzenes, 6 halogenated 

aromatics, 4 ethers, 1 aldehyde, and 1 nitrile. Many of 

the VOC target analytes have been the focus of national 

regulations, monitoring, and research during the past 

10 to 20 years. These include, for example, bromodichloromethane, chlorodibromomethane, tribromomethane, and trichloromethane, all of which are 

associated with the chlorination of drinking water; the 

fumigants l,2-dibromo-3-chloropropane (DBCP) and 

1,2-dibromoethane (EDB); the solvents tetrachloroethene (PCE) and trichloroethene (TCE); and the gasoline aromatic hydrocarbons benzene, methylbenzene 

(toluene), ethylbenzene, and dimethylbenzenes 

(xylenes), commonly referred to as BTEX compounds.

Most of the VOC target analytes have numerous 

uses in industry, commerce, and households (table 3). 

For example, the aromatic hydrocarbon, naphthalene, 

is used in the manufacturing of various organic chemicals, externally on livestock and poultry to control lice, 

as an ingredient of some moth repellents and toilet 

bowl deodorants, and formerly for intestinal vermifuge 

and wood preservative (Prager, 1995). Information 

about the amount of a compound's use for varied purposes is not systematically available for the United 

States. For the purpose of reporting frequency of 

occurrence information for VOCs in ground water and 

surface water, four predominant use categories are used 

in the NAWQA Program: (1) solvents, organic synthesis, and refrigerants; (2) fumigants; (3) gasoline 

aromatic hydrocarbons; and (4) gasoline oxygenates.

The predominant use for each VOC target 

analyte (table 3) is based on a review of available use 

information. These designations are applicable at the 

national level; the predominant use of a particular VOC 

may vary regionally and from location to location 

within a region. Therefore, it is appropriate that verification of actual use patterns be done in local, State, and 

regional studies.

SALIENT INFORMATION FOR TARGET 

ANALYTES

Additional information for each VOC target 

analyte is given in this section, including: (1) humanhealth and aesthetic concerns, cancer and noncancer 

risks, and drinking-water regulations, goals, and 

advisories; and (2) aquatic toxicity and water-quality 

guidelines. Also included is a listing and definition of

salient physical, chemical, and biological properties 

and information sources for these properties.

Human-Health and Aesthetic Concerns 

and DrJnkJng-Water Regulations

Human-health and aesthetic concerns, cancer 

and noncancer risks, and drinking-water regulations, 

goals, and advisories for the VOC target analytes are 

given in table 4. Unless noted otherwise, the information in table 4 was synthesized from two USEPA documents (U.S. Environmental Protection Agency, 1994, 

1996a). Human-health concerns of VCC target 

analytes include: (1) cancer; (2) liver, kidney, lung, 

circulation, nervous- and respiratory-system effects; 

(3) eye, skin, and throat irritation; (4) mental confusion; and (5) damage to blood cells. All but eight of the 

VOC target analytes have known or suspected humanhealth concerns. Furthermore, 28 of th~, VOC target 

analytes are classified as known, probable, or possible 

carcinogens. Benzene and chloroethen^ are known 

human carcinogens. It is noteworthy tl at 27 of the 55 

VOC target analytes have not been classified for carcinogenicity by the USEPA because of iradequate or no 

animal- and human-health evidence to assess carcinogenicity. At least 35 of the VOC target analytes have a 

noncancer human-health effect as evidenced by the 

existence of a DWEL concentration.

Thirty-three of the 55 VOC target analytes are 

known to impart taste or odor to water on the basis of 

published taste or odor threshold valuer. Table 4 lists 

threshold values and associated references for these 33 

compounds. Entries in this table list th^ lowest 

reported taste and odor threshold value.

Drinking-water regulations, goals, and health 

advisories are listed in the last three columns of table 4. 

National drinking-water regulations have been established by the USEPA for 29 VOC target analytes. 

Twenty-five of these VOC target analytes are regulated 

individually, and each has a Maximum Contaminant 

Level (MCL). Four VOC target analytes the 

trihalomethanes (bromodichloromethane, chlorodibromomethane, tribromomethane, and trichloromethane) are regulated on the basis of the sum of the 

concentrations of these four compounds. A drinkingwater regulation is a legally enforceable requirement 

that includes a MCL for the protection of human health 

that public water supplies can not exceed.

12 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Table 4. Human-health and aesthetic concerns, and drinking-water regulations, goals, and advisories (U.S. Environmental Pro

NAWQA volatile organic compound target analytes

[NAWQA, National Water-Quality Assessment; IUPAC, International Union of Pure and Applied Chemistry; Cancer risk E-5 level, concentration causing one 

DWEL, drinking-water equivalent level; MCL, Maximum Contaminant Level; MCLG, Maximum Contaminant Level Goal; ng/L, micrograms per liter; THM, 

£5'

t Information

o1

(5

a

8L

»

CO

IUPAC name

bromodichloromethane (THM)

bromomethane

chlorodibromomethane (THM)

chloroethane

chloromethane

1 ,2-dibromo-3-chloropropane

1 ,2-dibromoethane

dichlorodifluoromethane

1,1-dichloroethane

1 ,2-dichloroethane

dichloromethane

1 ,2-dichloropropane

hexachloroethane

tetrachloromethane 

tribromomethane (THM)

trichloromethane (THM) 

1,1,1 -trichloroethane 

1 , 1 ,2-trichloroethane

trichlorofluoromethane

1 ,2,3-trichloropropane 

1 , 1 ,2-trichloro- 1 ,2,2-trifluoroethane

bromoethene

chloroethene

Human-health concern

Cancer2

Nervous system effects4

Cancer

Eye, skin, and throat irritant

Mental confusion4

Cancer2

Cancer2

Inhalation irritant

Circulatory system effects4

Cancer2

Cancer2

Cancer, liver, and kidney effects2

Cancer

Cancer2 

Cancer2

Cancer2 

Liver, nervous system effects 

Liver, kidney, nervous system effects2

Mild irritant4

Cancer5 

Nervous system effects

Cancer5

Cancer2

Cancer 

rating1

Halogenated alkanes

B2

D

C

B

C

B2

B2

D

C

B2

B2

B2

C

B2 

B2

B2 

D 

C

D

Cancer risk 

E-5 level

6

.82

-

-

--

.3

.004

1,000

-

4

50

6

1

3 

40

60

175

B2 50 

210,000

Halogenated alkenes

-

A

-

.15

DWEL

700

50

700

-

100

--

~

5,000

-

-

2,000

--

40

30 

700

400 

1,000 

100

10,000

200

-

._

Taste or o

thresho

(H9/L)

-

-

-

6 19

~

~

~

~

67,000

6910

6 10

7 10

6520 

6300

62,400 

6970 

650,000

-

.

63,400
Table 4. Human-health and aesthetic concerns, and drinking-water regulations, goals, and advisories (U.S. Environmental Prot

NAWQA volatile organic compound target analytes Continued

Selection P

0

g

1

0)

a

0)

0)

I

1

Q>

1

S1

|

£*. 

(0

-*

3o'

O

§

|

m

TJ

an

SN°

S. 5"

<D

z

i

o

2

o

(D

5

3

IUPAC name Human-health concern

Cancer ^TJJJjJj*: DWEL

Taste or o

threshol

Halogenated alkenes Continued

1 , 1 -dichloroethene

cis-l ,2-dichloroethene

t rans- 1 ,2-dichloroethene

cis- 1 ,3-dichloropropene

trans-l ,3-dichloropropene

hexachlorobutadiene

tetrachloroethene

trichloroethene

Cancer, liver and kidney effects2

Liver, kidney, nervous, circulatory system effects2

Liver, kidney, nervous, circulatory system effects2

Cancer5

-

-

Cancer2

Cancer2

C

D

D

B2 2

B2 2

C 1

7

B2 30

400

400

600

10

10

70

500

300

6 1,500

74

-

-

76

6 190

6310

Aromatic hydrocarbons

benzene

naphthalene

styrene

n-butylbenzene

1 ,2-dimethylbenzene

1 ,3-dimethylbenzene

1 ,4-dimethylbenzene

ethylbenzene

methylbenzene

wo-propylbenzene

«-propylbenzene

1 ,2,4-tiimethylbenzene

Cancer2

Liver, reproductive system effects2

Liver, nervous system effects2

Alkyl

~

Liver, kidney, nervous system effects2

Liver, kidney, nervous system effects

^

Liver, kidney, nervous system effects

Liver, kidney, nervous system effects2

Liver, kidney, nervous, circulatory effects2

Nervous system effect, eye and skin irritant4

-

xvCSpirzuory, nsrvous svScSTn SAA^C».S

A 10

D

C

benzenes

..

D

D

D

D

D

23.3

-

~

100

7,000

60,000

60,000

60,000

3,000

7,000

-

~

6 170

82

6 11

6 17

--

629

642

6

-

7SOO

Halogenated aromatics

chlorobenzene

1 ,2-dichlorobenzene

1 ,3-dichlorobenzene

 3

Nervous system effects

Liver, kidney, respiratory, nervous system effects4

Liver, kidney, blood cell damage2

D

D

D 600

700

3,000

3,000

650

624

87?
Table 4. Human-health and aesthetic concerns, and drinking-water regulations, goals, and advisories (U.S. Environmental Pro

NAWQA volatile organic compound target analytes Continued

« i -r * 

c Cancer risk nwFi Taste or o

lUPACname Human-health concern cancer uwbL thresho

rating ' . _ . C-tg/L) / \ 

(JAg/L) (jig/L) 

1 ,4-dichlorobenzene Cancer2

1 ,2,3-trichlorobenzene

f\

1 ,2,4-trichlorobenzene Liver, kidney effects

Halogenated aromatics Continued

C -- 4,000 84

7 1Q

D -- 40 75 

Ethers

tert-amyl methyl ether 

diisopropyl ether 

ethyl tert-butyl ether 

methyl tert-butyl ether

2-propenal

Strong irritant4

C 70 

(tentative)

Others (aldehydes and nitriles)

Respiratory system effects, eye and skin irritant5 C

1,000

5 15

'110

w

(O

2-propenenitrile Cancer B .6 69,100 

'Carcinogen rating as determined by U.S. Environmental Protection Agency (1996a).

A, Human carcinogen sufficient evidence in epidemiologic studies to support causal association between exposure and cancer;

B j, Probable human carcinogen limited evidence in epidemiological studies;

B2, Probable human carcinogen sufficient evidence from animal studies;

C, Possible human carcinogen limited or equivocal evidence from animal studies and inadequate or no data from human studies;

D, Not classified inadequate or no human and animal evidence of carcinogenicity; and

E, No evidence of carcinogenicity for humans. No evidence of carcinogenicity in at least two adequate animal tests in different species or in adeq

--, Information not available 

2U.S. Environmental Protection Agency, 1994. 

3Total for THMs is 100 ng/L. 

4Prager, 1995. 

5Lewis, 1997.

6Ammore and Hautala, 1983. 

7Verschueren, 1983. 

8Young and others, 1996.

9This advisory is based on aesthetic reasons (taste and/or odor properties). 

10U.S. Environmental Protection Agency, 1997.
The USEPA has established Maximum Contaminant Level Goals (MCLGs) for 33 of the VOC target 

analytes. The MCLG is a nonenforceable concentration of a drinking-water contaminant that is protective 

of adverse human-health effects and allows an adequate margin of safety. Most of the compounds classified as known or probable carcinogens have an MCLG 

set at zero; that is, the goal is that these compounds are 

not present in drinking water.

The USEPA has also established lifetime health 

advisories for drinking water, and 26 of the VOC target 

analytes have such an advisory. One additional VOC 

target analyte, methyl tert-butyl ether, has an aesthetic 

advisory for taste and odor concerns. Drinking-water 

health advisories are provided for various exposure 

durations including 1-day, 10-day, long-term (approximately 7 years), and lifetime (U.S. Environmental 

Protection Agency, 1996a). Lifetime health advisories 

for the VOC target analytes are given in the last column 

of table 4. This advisory is defined by the USEPA as 

the concentration of a chemical in drinking water that 

is not expected to cause any adverse noncarcinogenic 

effect over a lifetime of exposure within a specified 

margin of safety. Health advisories serve as informal 

technical guidance to the States and water utilities for 

protecting public health when contamination situations 

occur in drinking-water supplies.

Aquatic Toxicity and Water-Quality 

Guidelines

Detailed information on the aquatic toxicity of 

the VOC target analytes and other VOCs has been 

reported recently by Rowe and others (1997). That 

publication provides a comprehensive listing of aquatic 

toxicity data for each VOC target analyte for each 

aquatic organism tested to date. Select information for 

aquatic toxicity adapted from Rowe and others (1997) 

is given in table 5 including the lowest concentration 

and associated effect for the most sensitive species. 

Freshwater, water-quality guidelines established by the 

USEPA and Environment Canada are also listed in 

table 5.

The lowest concentration and effect information 

listed in table 5 were derived from USEPA's AQUIRE 

data base (U.S. Environmental Protection Agency, 

1996b). AQUIRE, a centralized international source 

for toxic effects information, has been updated periodically for the past 17 years. To be included in table 5, 

toxicity studies listed in AQUIRE had to meet the following criteria: (1) studies must have been conducted

in freshwater, and (2) studies must have complete or 

moderately complete documentation of test procedures. Toxicity information listed in table 5 is based on 

information retrieved from AQUIRE in 1997.

Aquatic toxicity tests typically are conducted by 

exposing organisms to a range of contaminant concentrations under controlled conditions and measuring the 

response of the organisms (Rand and Pet~ocelli, 1985). 

Acute toxicity tests are used to determine if solutions 

are toxic to species during short-duration exposures 

(typically 96 hours or less), and species mortality is the 

most common endpoint. Chronic toxicity tests use a 

longer duration of exposure (typically 7 days or more). 

Responses other than species mortality typically are 

measured during chronic tests and may include 

changes in reproduction, growth, and behavior. No 

exact duration or response, however, distinguishes 

acute nor chronic toxicity tests.

The majority of published toxicity information 

for VOCs are median lethal concentration (LC50) 

values, the estimated concentrations at which 50 percent of the organisms died during the toxicity test. The 

median effective concentration (EC50) is the estimated 

concentration that affects 50 percent of the organisms; 

however, the endpoint of the test is an effect other than 

mortality. Other toxicity information ftr VOCs 

include: (1) no observed effective concentration 

(NOEC), the highest concentration at wl ich effects are 

not found or are not statistically significant; (2) lowest 

observed effective concentration (LOEC), the lowest 

concentration producing a statistically significant 

effect; and (3) maximum acceptable toxicant concentration (MATC), the chronic value representing the 

hypothetical threshold concentration that is the 

geometric mean between the NOEC and LOEC 

concentrations.

Some aquatic species are more sensitive to certain contaminants than others and are af "ected at lower 

concentrations. Furthermore, some compounds are 

acutely toxic to a species over a relative'y narrow concentration range. When this occurs, the lowest concentration that affects the species is reported in table 5 as a 

range rather than a single value. Four measures of 

aquatic toxicity were reviewed for each VOC target 

analyte to determine the lowest concentration and associated effect. In order of precedence, these include the 

MATC, LOEC, EC50, and LC50. The lowest concentrations, measured in micrograms per li^er, were available for 42 of the 55 VOC target analytes, and the 

lowest concentrations ranged from 6.5 to 13 ^ig/L for 

hexachlorobutadiene to 672,000 ^lg/L for methyl tertbutyl ether.

16 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Table 5. Lowest concentrations of volatile organic compound target analytes that affect the most sensitive aquatic species, and 

from Rowe and others, 1997)

[Values in micrograms per liter unless otherwise indicated; IUPAC, International Union of Pure and Applied Chemistry; when available, the lowest concentratio

MATC, maximum acceptable toxicant concentration; LOEC, lowest observed effective concentration; EC50, median effective concentration; LC^Q, median leth

'<, less than; >, greater than]

W

(O

o

TaxoIUPAC nomic 

name classification

bromodichloromethane 

bromomethane fish

chlorodibromomethane fish

chloroethane

chloromethane fish

l,2-dibromo-3-chloro- fish 

propane

1,2-dibromoethane fish

dichlorodifluoromethane 

1 , 1 -dichloroethane

1,2-dichloroethane fish

dichloromethane amphibian

1 ,2-dichloropropane fi sh

Genus, species/ 

Common name

-

Oryzias latipesl 

Medaka, high eyes

Cyprinus carpiol 

Common, mirror, 

colored carp

~

Lepomis macrochirusl 

Bluegill

Lepomis macrochirusl 

Bluegill

Micropterus salmoidesl 

Largemouth bass

~

~

Pimephales promelasl 

Fathead minnow

Rana catesbeianal 

Bullfrog

Pimephales promelasl 

Fathead minnow

Lowest concentration and effect

EndMATC LOEC EC50 LC50 point 

effect1

Halogenated alkanes

-

nv nv 400 - BEH

nv nv nv 34,000 MOR

-

nv nv nv 550,000 MOR

nv nv nv 20,000 MOR

nv nv nv 15,000 MOR

-

-

29,000- - ~ - GRO 

59,000

nv nv 17,780 -- TER

6,000- - - - GRO 

11,000

 Duration 

of test 

(hours)

-

96

72-120

--

96

48

24

-

-

768

192

768

USE

fresh

acu

guide

11

11

11

4860

11

118

11

hexachloroethane fish Oncorhynchus mykissl 

Rainbow trout, 

donaldson trout

67-207 GRO 768 
ji Table 5. Lowest concentrations of volatile organic compound target analytes that affect aquatic species and water-quality guide

*9 

O

5"

3 

O

o 

o

Q.

C"1

3

Q.

^5'

3"

o*

3

2.

0

3

3"

^

o

»

o 

O

(Q

3o"

OO

3 o

o

c

3

Q. 

COm

3 o

 y

B

Q.

5"

o

1O

o

(Q

3

IUPAC 

name

tetrachloromethane

tribromomethane

trichloromethane

1,1,1 -trichloroethane

1 , 1 ,2-trichloroethane

trichlorofluoromethane

1 ,2,3-trichloropropane

1,1,2-trichloro- 1,2,2-

trifluoroethane

bromoethene

chloroethene

1,1-dichloroethene

cis- 1 ,2-dichloroethene

irons- 1 ,2-dichloroethene

T Lowest concentration and effect USE

nomic Genus, species/ - . u,r? '°n freshw

.... « End' of test 

c assifi- Common name MATS* i «er» c/* i r» «: * /u x acu

MATC LOEC ECcn LC50 point (hours) .... 

cation effect1 guidel

Halogenated alkanes Continued

fish Pimephales promelasl 52,100 - - - MOR 168 35,

Fathead minnow

plant Selenastrum nv nv 38,600 ~ CLR 96 11

capricornutuml

Green algae

amphi- Hyla cruciferl nv nv 270 - TER 168 28,

bian Spring peeper

fish Pimephales promelasl nv nv 11,100 -- IMM 72 18,

Fathead minnow

fish Oncorhynchus mykiss/ 6,000- - - ~ GRO 768 18,

Rainbow trout, 14,800

donaldson trout

11,

fish Pimephales promelasl nv nv nv 66,500 MOR 96

Fathead minnow

..

Halogenated alkenes

__

~

plant Scenedesmus abundansl nv nv 410,000 - GRO 96 11,

Green algae

11,

insect Daphnia magnal nv nv nv 220,000 MOR 48 11,

Water flea
Table 5. Lowest concentrations of volatile organic compound target analytes that affect aquatic species and water-quality guid

CO

to

9

r*

1

3

&0

a*

o ^

^0>

,2(a 

&

£

o>

f

£

TaxoIUPAC nomic 

name classification

cis- 1 ,3-dichloropropene 

trans- 1 ,3-dichloropropene

hexachlorobutadiene fish

tetrachloroethene fish

trichloroethene fish

benzene fish

naphthalene insect

styrene fish

n-butylbenzene insect

1 ,2-dimethylbenzene fish

1,3-dimethylbenzene plant

Genus, species/ 

Common name

~

~

Pimephales promelasl

Fathead minnow

Oncorhynchus mykissl

Rainbow trout,

donaldson trout

Jordanella floridael

Flagfish

Pimephales promelasl

Fathead minnow

Daphnia magnal

Water flea

Oncorhynchus mykissl

Rainbow trout,

donaldson trout

Daphnia magnal

Water flea

Oncorhynchus kisutchl

Coho salmon, silver

salmon

Selenastrwn

capricomutuml

Green algae

Lowest concentration and effect MC

 Duration . U7 

c-j .. . fresh

End- of test 

MATC LOEC ££50 LCso point (hours) . . 

Halogenated alkenes Continued

6

6

6.5-13 -- -- - GRO 768 

500- - - - GRO 768 5

1,400

nv 11,000 ~ ~ MOR 240 45

Aromatic hydrocarbons

nv 17,200 ~ - GRO 168 5

nv nv 690 - PTR 2 2

nv nv nv 2,500 MOR 24

Alkyl benzenes

490 - - - IMM 48

nv nv 600 ~ AVO 1

nv nv 3,900 ~ GRO 192
Table 5. Lowest concentrations of volatile organic compound target analytes that affect aquatic species and water-quality guide

Selection Pro

s

a

c

3

3

a 

»

5'

3"

3"

i%5'

3

3"

^

o

I

3T

O

1o

5*

1o

c

COV o

3" 

CO5'

S. 5"

Er

z

1

1

1

IUPAC 

name

1 ,4-dimethylbenzene

ethylbenzene

methylbenzene

wo-propylbenzene

n-propylbenzene

1 ,2,4-trimethylbenzene

chlorobenzene

1 ,2-dichlorobenzene

1 ,3-dichlorobenzene

1 ,4-dichlorobenzene

1 ,2,3-trichlorobenzene

Taxonomic 

classification

plant

insect

fish

insect

plant

insect

insect

insect

fish

fish

insect

Genus, species! 

Common name

Selenastrum

capricornutuml

Green algae

Daphnia magnal

Water flea

Pimephales promelasl

Fathead minnow

Daphnia magnal

Water flea

Selenastrum

capricornutuml

Green algae

Daphnia magnal

Water flea

Daphnia magnal

Water flea

Daphnia magnal

Water flea

Oncorhynchus mykissl

Rainbow trout,

donaldson trout

Oncorhynchus mykissl

Rainbow trout,

donaldson trout

Daphnia magnal

Water flea

Lowest concentration and effect

EndMATC LOEC EC50 LC50 point 

effect1

Alkyl benzenes Continued

nv nv 3,200 - GRO

nv nv 1,810 -- IMM

nv 6,000 - - GRO

nv nv 601 -- IMM

nv nv 1,800 ~ GRO

nv nv 3,600 - IMM

Halogenated aromatics

nv nv 585 - IMM

nv nv 550 - REP

555- - - -- GRO

1,040

565- - -- - GRO

1,^40

nv nv 200 - REP

_ .. USE

Du;f °" freshw

of test 

,. . acu

* urs' guide

72

24 32

768 17

48

72

48

48 

336 1

768 1

768 1

336
Table 5. Lowest concentrations of volatile organic compound target analytes that affect aquatic species and water-quality guid

Salient Information forTJ

»

a

Q> i

Taxo- Lowest concentration and effect US

IUPAC nomic Genus, species/ End_ UJ? '°n fresh

name classifi- Common name MAT/* i ncr* cr* i r» ««!,,» /u > ac

MATC LOEC EC5o LCso point (hours) . . 

cation w w effect1 guide

Halogenated aromatics Continued

1,2,4-trichlorobenzene fish Oncorhynchus mykissl 406 -- -- -- GRO 1,080 

Rainbow trout, 

donaldson trout

Ethers

tert-amyl methyl ether

diisopropyl ether fish Pimephales promelasl nv nv nv 91,700 MOR 96 

Fathead minnow

ethyl terf-butyl ether

methyl terf-butyl ether fish Pimephales promelasl nv nv nv 672,000 MOR 96 

Fathead minnow

Others (aldehydes and nitriles)

2-propenal insect Daphnia magnal nv nv 51 IMM 48 

Water flea

2-propenenitrile insect Daphnia magnal nv nv 10,950 -- IMM 48 7

Water flea

^dpoint effect: AVO, avoidance; BEH, behavior; BMS, biomass; CLR, chlorophyll; GRO, growth; IMM, immobilization; MOR, mortality; PTR, pho

REP, reproduction; TER, teratogenesis. 

2U.S. Environmental Protection Agency, 1996c. 

3Canadian Council of Resource and Environmental Ministers, 1991. 

4 l-hour average, freshwater acute water-quality guidelines. 

54-day average, freshwater chronic water-quality guidelines.
Water-quality guidelines published by the 

USEPA for protection of freshwater biota are available 

for 33 of the 55 VOC target analytes, and 17 have 

water-quality guidelines established by Environment 

Canada (table 5). Information concerning these guidelines was obtained from USEPA's Integrated Risk 

Information System (IRIS) (U.S. Environmental 

Protection Agency, 1996c) and from Environment 

Canada (Canadian Council of Resource and Environment Ministers, 1991). When toxicity information is 

insufficient to develop criteria, the USEPA uses values 

equal to the LOEC as a guideline. The acute and 

chronic criteria are based on the highest concentration 

of a pollutant that freshwater aquatic organisms can be 

exposed to for an established period of time without 

deleterious effects. Nonenforceable Canadian guidelines are based on short-term toxicity data (96-hour 

LCso) of the most sensitive species multiplied by application factors of 0.05 for nonpersistent effects and 0.01 

for persistent effects (Canadian Council of Resource 

and Environment Ministers, 1991).

Physical, Chemical, and Biological 

Properties

Transport, behavior, and fate of VOCs are determined by a combination of various physical, chemical, 

and biological properties (Rathbun, 1998). The most 

important physical, chemical, and biological properties 

of the VOC target analytes used to predict their aquatic 

behavior and fate include: aqueous solubility, vapor 

pressure, Henry's law constant, octanol-water partitioning coefficient, sorption coefficient, half-life 

(hydrolysis, photolysis, chemical oxidation, and 

aerobic and anaerobic biodegradation), and bioconcentration factors. Definitions for these properties are 

given in appendix 2.

Several references have already compiled a vast 

majority of the physical, chemical, and biological 

properties for the VOC target analytes. Especially 

noteworthy are the comprehensive compilations 

reported by Rathbun (1998), Howard (1990, 1991a, 

1991b, 1993, 1997), Howard and others (1991), and 

Mackay and others (1992a, 1992b, 1993,1995). Other 

reference texts and several journals have additional 

physical, chemical, and biological data for the VOC 

target analytes.

REFERENCES CITED

Ammore, I.E., and Hautala, E.,1983, Odor as an aid to 

chemical safety: Odor thresholds compared with 

threshold limit values and volatilities for 214 industrial 

chemicals in air and water dilution: Jcrjrnal of Applied 

Toxicology, vol. 3, no. 6, p. 272-290.

Canadian Council of Resource and Environment Ministers, 

1991, Canadian water quality guidelines: Ottawa, 

Ontario, Environment Canada, Inland Waters 

Directorate, Water Quality Branch, updated May 1996 

[variously paged].

Connor, B.F., Rose, D.L., Noriega, M.C., Mnrtagh, 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 Open-File Report 97-829, 78 p.

Hirsch, R.M., Alley, W.M., and Wilber, W.G., 1988, Concepts for a national water-quality assessment: U.S. 

Geological Survey Circular 1021, 42 p.

Howard, P.H., 1990, Handbook of environmental fate and 

exposure data for organic chemicals Volume I, Large 

production and priority pollutants: Lewis Publishers, 

Inc., Chelsea, Mich., 574 p.

___199la, Handbook of environmental fate and exposure 

data for organic chemicals Volume II, Solvents: 

Lewis Publishers, Inc., Chelsea, Mich., 546 p.

___1991b, Handbook of environmental fate and exposure 

data for organic chemicals Volume HI, Pesticides: 

Lewis Publishers, Inc., Chelsea, Mich., 684 p.

___1993, Handbook of environmental frte and exposure 

data for organic chemicals Volume IV, Solvents 2: 

Lewis Publishers, Inc., Chelsea, Mich., 578 p.

___1997, Handbook of environmental frte and exposure

data for organic chemicals Volume V, Solvents 3: 

Lewis Publishers, Inc., Chelsea, Mich., 491 p.

Howard, PH., Boethling, R.S., Jarvis, WE, Meylan, W.M., 

and Michalenko, E.M., 1991, Handbook of environmental degradation rates: Lewis Publishers, Inc., 

Chelsea, Mich., 725 p.

Leahy, PP., and Thompson, T.H., 1994, U.S. Geological 

Survey National Water-Quality Assessment Program: 

U.S. Geological Survey Open-File Report 94-70, 4 p.

Lewis, R.J., ed, 1997, Sax's dangerous properties of industrial materials, in Comprehensive Chemical Contaminant series, Environmental Sciences Electronic 

Resources (9th ed.): Van Nostrand Reinhold, New 

York [cd-rom disk].

Mackay, Donald, and Shiu, W.Y., 1990, Physical-chemical 

properties and fate of volatile organic compounds An 

application of the fugacity approach, in Ram, N.M., and 

others, eds., Significance and treatment of volatile 

organic compounds in water supplies: Lewis 

Publishers, Inc., Chelsea, Mich., p. 1P3-204.

22 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWQA Program
Mackay, Donald, Shiu, W.Y., and Ma, K.C., 1992a, Illustrated handbook of physical-chemical properties and 

environmental fate for organic chemicals Volume I, 

Monoaromatic hydrocarbons, chlorobenzenes, and 

PCBs: Lewis Publishers, Inc., Chelsea, Mich., 697 p.

 1992b, Illustrated handbook of physical-chemical 

properties and environmental fate for organic chemicals Volume II, Polynuclear aromatic hydrocarbons, 

poly chlorinated dioxins, and dibenzofurans: Lewis 

Publishers, Inc., Chelsea, Mich., 597 p.

 1993, Illustrated handbook of physical-chemical 

properties and environmental fate for organic chemicals Volume III, Volatile organic chemicals: Lewis 

Publishers, Inc., Chelsea, Mich., 916 p. 

-1995, Illustrated handbook of physical-chemical

properties and environmental fate for organic chemicals Volume IV, Oxygen, nitrogen, and sulfur containing compounds: Lewis Publishers, Chelsea, Mich., 

962 p.

Nowell, L.H., and Resek, E.H., 1994, Summary of national 

standards and guidelines for pesticides in water, bed 

sediment, and aquatic organisms and their application 

to water-quality assessments: U.S. Geological Survey 

Open-File Report 94-44, 115 p.

Pankow, J.F., and Cherry, J.A., 1996, Dense chlorinated 

solvents and other DNAPLs in groundwater: Waterloo 

Press, Portland, Oreg., 522 p.

Prager, J.C., 1995, Environmental contaminant reference 

databook Volume I: Van Nostrand Reinhold, New 

York, 1,240 p.

Rand, G.M., and Petrocelli, S.R., 1985, Fundamentals of 

aquatic toxicology: Hemisphere Publishing Corporation, Washington, D.C., 666 p.

Rathbun, R.E., 1998, Transport, behavior, and fate of volatile organic compounds in streams: U.S. Geological 

Survey Professional Paper 1589, 151 p.

Rose, D.L., and Schroeder, M.P., 1995, Methods of analysis 

by the U:S. Geological Survey National Water Quality 

Laboratory Determination of volatile organic compounds in water by purge and trap capillary gas 

chromatography/mass spectrometry: U.S. Geological 

Survey Open-File Report 94-708, 26 p.

Rowe, B.L., Landrigan, S.J., and Lopes, T.J., 1997, Summary of published aquatic toxicity information and 

water-quality criteria for selected volatile organic 

compounds: U.S. Geological Survey Open-File Feport 

97-563, 60 p.

Schwarzenbach, R.P., Gschwend, P.M., and Imboden, D.M., 

1993, Environmental organic chemistry: John Wiley 

and Sons, Inc., New York, 681 p.

U.S. Environmental Protection Agency, 1994, Is your drinking water safe?: EPA 810-F-94-002, Office of Water, 

Washington, D.C., May, 19 p.

 1996a, Drinking water regulations and health 

advisories: EPA 822-B-96-002, Washington, D.C., 

October, 13 p.

 1996b, AQUatic toxicity Information REtrieval data 

base (AQUIRE): U.S.Environmental Protection 

Agency, Environmental Research Laboratory, Duluth, 

Minn., data retrieved May 1996 (electronic data files).

 1996c, Integrated Risk Information System (IFIS): 

U.S. Environmental Protection Agency, Office of 

Health and Environmental Assessment, Research 

Triangle Park, N.C., electronic data files (Dec. IS96 

update).

 1997, Drinking water advisory Consumer acceptability advice and health effects analysis on methyl 

tertiary-butyl ether (MTBE): Office of Water, 

Washington, D.C., EPA-822-F-97-009, 34 p. 

 1998, 1996 Toxic release inventory Public drta

release Ten years of right-to-know: Office of 

Pollution Prevention and Toxics, Washington, D.C., 

EPA 745-R-98-005, 408 p. with appendices.

Verschueren, Karel, 1983, Handbook of environmental data 

on organic chemicals: Van Nostrand Reinhold, New 

York, 1,310 p.

Young, W.F., Horth, H., Crane, R., Ogden, T, and Arnott, 

M., 1996, Taste and odour threshold concentrations of 

potential potable water contaminants: Water 

Resources, v. 30, no. 2, p. 331-340.

References Cited 23
APPENDIXES
Appendix 1 . Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

[IUPAC, International Union of Pure and Applied Chemistry; DWEL, drinking-water equivalent level; CWQC, chronic water-quality criteria; <, less than or equ

if

I

o

Procedure ai

a

e5'

3

5"

3"

i

o"

3"

<

I

<D

0

D)

3o'

O 

O

3

TJ 

O

C

1

m

3

TJ

D) 

(0N"

<D

a 

5'

<D

i

o

T3

3 

(0

5

3

U.S. Geological S

Compound 

number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

urvey National Water Quality Laboratory; SH, Nati<

Candidate target analyte

IUPAC name

acrylamide

benzene

bromodichloromethane

bromoethene

chloroethane

chloroethene

few-(2-chloroethyl) ether

fow-(2-chloroethyl) sulfide

few-(chloromethyl) ether

chloromethyl methyl ether

1 ,2-dibromo-3-chloropropane

1 ,2-dibromoethane

1,2-dichloroethane

dichloromethane

1 ,2-dichloropropane

cis- 1 ,3-dichloropropene

trans- 1 ,3-dichloropropene

1 ,4-dinxane

formaldehyde

2-propenenitrile

tetrachloromethane

Mial Water Quality Laboratory analysis sclledule; --, informsition not available]

Information used in the Phase 1 screening procedure 

to identify compounds as candidate target analytes

Physical 

properties 

typical of 

VOCs

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Human 

carcinogen 

rating1

B2

A

B2

A

B

A

B2

A

A

A

B2

B2

B2

B2

B2

B2

B2

B2

BI

BI

B2

DWEL

7

..

700

--

~

--

8

--

--

2,000

~

10

10

5,000

--

30

CWQC or _ 

aquatic Occ

toxicitv frequen

. _,/. water sa

..

_

..

230,000

-

-

..

..

20,000

» __ 

-

244

244

..

2,600

-
Appendix 1 . Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

Candidate target analyte

Compound ,UPAC name 

number

Appendix 1

*,*

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41 

42 

43

44

tribromomethane

trichloroethene

trichloromethane

1 ,2,3-trichloropropane

bromomethane

chloromethane

hexachlorobutadiene

hexachloroethane

naphthalene

pentachlorobenzene

1 ,2,4-trichlorobenzene

1 , 1 ,2-trichloroethane

/i-butylbenzene

chlorobenzene

hexachlorocyclopentadiene

2-propenal

/so-propylbenzene

/i-propylbenzene

chlorodibromomethane

1 ,2-dichlorobenzene 

1 ,3-dichlorobenzene 

1 ,4-dichlorobenzene

1 ,1 -dichloroethane

Information used in the Phase 1 screening procedure 

to identify compounds as candidate target analytes

Physical 

properties 

typical of 

VOCs

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes 

Yes 

Yes

Yes

Human 

carcinogen 

rating1

B2

B2

B2

B2

D

C

C

C

D

--

D

C

-

D

D

--

--

--

C

D 

D 

C

DWEL

(ng/L)

700

300

400

200

50

100

70

40

100

28

40

100

-

700

200

--

--

--

700

3,000 

3,000 

4,000

CWQC or _ 

aquatic . °CC

toxicity frequen

(MIL) water sa

--

21,900

1,240

--

--

--

9.3

540

620

50

50

9,400

2490

50

5.2

21

2610

2 1,800

Yes

763 Yes 

763 Yes 

763 Yes

Yes
Appendix 1 . Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

Selection Proced

3

IB

0.

CO

IB

I

1o

1

<T

i

»" 

O

(2

IB

o"

O

|

C

1

m

TJ3" 

IB 

CON*

S.

3

E*

(D

Z

I

O

 o

J

5

3

Compound 

number

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

Candidate target analyte

IUPAC name

1 , 1 -dichloroethene

cis-l ,2-dichloroethene

irons- 1 ,2-dichloroethene

dichlorodifluoromethane

1 ,2-dimethylbenzene

1 ,3-dimethylbenzene

1 ,4-dimethylbenzene

ethylbenzene

methylbenzene

methyl tert-butyl ether

styrene

tetrachloroethene

1,1,1 -trichloroethane

trichlorofluoromethane

1 ,2,4-trimethylbenzene

1 , 1 ,2-trichloro- 1 ,2,2-trifluoroethane

1 ,2,3-trichlorobenzene

tert-amy\ methyl ether

diisopropvl ether

ethyl tert-butyl ether

bromobenzene

bromochloromethane

2-butanone

Information used in the Phase 1 screening procedure 

to identify compounds as candidate target analytes

Physical 

properties 

typical of 

VOCs

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Human 

carcinogen 

rating1

C

D

D

D

D

D

D

D

D

C(tentative)

C

D

D

-

--

-

--

~

-

~

_

DWEL

400

400

600

5,000

60,000

60,000

60,000

3,000

7,000

1,000

7,000

500

1,000

10,000

-

~

~

--

-

--

~

50

_

CWQC or 

aquatic , OcCU

toxicity frequen

(ng/L) water sa

20,000 Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

840 Yes

Yes

Yes

Yes

-

__

__

-

-

~

--

_
Appendix 1 . Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

Candidate target analyte

Compound lUPACname 

number

Appendix 1

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87 

88 

89

90

terr-butylbenzene

terr-butyl formate

few-(2-chloroisopropyl) ether

1 -chloro-2-methylbenzene

1 -chloro-4-methylbenzene

dibromomethane

dichloroacetonitrile

1 , 1 -dichloropropane

1 ,3 -dichloropropane

2,2-dichloropropane

1 , 1 -dichloropropene

n-hexane

isophorone

1 -isopropyl-4-methylbenzene

( 1 -methylpropyl)benzene

pentachloroethane

phenol

1,1,1 ,2-tetrachloroethane

1 ,1 ,2,2-tetrachloroethane

trichloroacetonitrile 

1 ,3,5-trichlorobenzene 

1 ,3,5-trimethylbenzene

benzidine

Information used in the Phase 1 screening procedur

to identify compounds as candidate target analyte

Physical 

properties 

typical of 

VOCs

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes 

Yes 

Yes

No

Human 

carcinogen 

rating1

--

--

D

D

D

D

C

--

--

--

--

D

C

--

--

--

D

C

--

D

-_

CWQCor 

DWEL aquatic f^*

(Mfl/L) tox,c,ty wat;;r S

(ng/L) 

1,000 -- 

700 -- 

700 -- 

300 - 

5,700 

5,700 

5,700 

244 

7,000 -- 

1,200 

20,000 2,560 

1,000 - 

2,400 

200 -- 
Appendix 1 . Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

9 

ss. 

0

T> 

O

S

a

3

0)

3

a

<n

£. 5"

3

5[

|

o'

o"

o

0)E*

<D

0

0)

o'

O 

0

3 a 

o

c

3

a.

(0

V a

I

S

a

5'

z

|O

TJ

3

CO

5

Compound 

number

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

Candidate target analyte

IUPAC name

bromochloroacetonitrile

chloroacetic acid

4-chloro-3-methylphenol

(chloromethyl) oxirane

2-chlorophenol

4-chlorophenol

chloropicrin

dichloroacetic acid

dichloroacetylaldehyde

3,3-dichlorobenzidine

2,4-dichlorophenol

2,4-dimethylphenol

1 ,3-dinitrobenzene

2,4-dinitro-o-cresol

2,4-dinitrotoluene

2,6-dinitrotoluene

diphenylamine

diphenylhydrazine

ethylene glycol

ethylene thiourea

hexachlorobenzene

maleic hydrazide

nitrobenzene

Information used in the Phase 1 screening procedure 

to identify compounds as candidate target analytes

Physical 

properties 

typical of 

VOCs

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

Human 

carcinogen 

rating1

--

-

--

B2

D

--

--

B2

--

--

D

D

B2

B2

D

D

B2

B2

D

__

DWEL

--

-

--

70

200

--

--

100

--

--

100

--

5

~

100

40

1,000

--

40,000

3

30

20,000

CWQCor Qcc

aquatic , 

. . frequen

, .,Y water sa
Appendix 1. Volatile organic compounds (VOCs) considered as candidate target analytes and results of Phase 1 of screening 

1 

a

Compound 

number

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

Candidate target analyte

IUPAC name

4-nitrophenol

nitroquanidine

n-nitrosodibutylamine

n-nitrosodiethylamine

n-nitrosodimethylamine

n-nitrosodiphenylamine

nitrosodi -n-propylamine

n-nitrosopyrrolidine

pentachlorophenol

picloram

1 ,2,4,5-tetrachlorobenzene

2,3 ,5 ,6-tetrachlorophenol

trichloroacetic acid

trichloroethanol

2,4,5-trichlorophenol

2,4,6-trichlorophenol

toxaphene

Information used in the Phase 1 screening procedu

to identify compounds as candidate target analyte

Physical 

properties 

typical of 

VOCs

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

No

Human 

carcinogen 

rating1

D

D

--

--

--

-

--

--

B2

D

--

--

C

--

--

B2

B2

°WQ(: 0r Oc

DWEL aquatic . 

, x . . .. frequ

(ug/L) toxicity * 

v ' . ' water 

300

4,000

--

--

--

-

--

--

1,000

2,000

--

--

4,000

--

--

--

--

'Carcinogen rating as determined by U.S. Environmental Protection Agency (1996a).

A, Human carcinogen sufficient evidence in epidemiologic studies to support causal association between exposure and cancer;

Bj, Probable human carcinogen limited evidence in epidemiological studies;

62, Probable human carcinogen sufficient evidence from animal studies;

C, Possible human carcinogen limited or equivocal evidence from animal studies and inadequate or no data from human studies;

D, Not classified inadequate or no human and animal evidence of carcinogenicity; and

E, No evidence of carcinogenicity for humans. No evidence of carcinogenicity in at least two adequate animal tests in different species or in ade

 , Information not available 

^Selected fmm I JSRPA's AQIJ1RF, (I JSEPA, \996b) database because of low toxicitv. A safetv factor of 100 was aoolied to this value for selection bec
Appendix 2. Definitions for physical, chemical, and biological properties

Aqueous solubility

Vapor pressure 

Henry's law constant

Octanol-water partitioning coefficient 

Sorption coefficient 

Half-life 

Bioconcentration factor

A measure of the pure compound's abundance by volume in the aqueous phase when the 

solution is in equilibrium with the pure compound in its actual aggregation state (gas, 

liquid, solid) at a specified temperature and pressure (Schwarzenbad and others, 1993).

The pressure of the vapor of a compound at equilibrium with its pure condensed phase, be it 

liquid or solid (Schwarzenbach and others, 1993).

The ratio of a compound's abundance in the gas phase to the abundance in the aqueous 

phase at equilibrium at a specific temperature and pressure (Schwarzenbach and others, 

1993).

The subdivision of a population of molecules between the octanol and water phases 

(Schwarzenbach and others, 1993).

The subdivision of a population of molecules between the organic carb~m and water phases 

(Schwarzenbach and others, 1993).

A measure of the time in which the concentration of the compound is lowered by a factor of 

2 (Schwarzenbach and others, 1993).

A measure of the uptake from water of the compound by organisms within an aquatic 

system (Rathbun, 1998).

32 Selection Procedure and Salient Information for Volatile Organic Compounds Emphasized in the NAWOA Program

 fr U.S. GOVERNMENT PRINTING OFFICE: 1999 773-090 / 24516 Region No. 8