©EPA
EPA/600/R-08/021 I October 2008 I www.epa.gov/ord
  United States
  Environmental Protection
  Agency

                 Risk-Based Criteria to
                 Support Validation of
                 Detection Methods for
                 Drinking Water and Air

  Office of Research and Development
  National Homeland Security Research Center

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                                                        EPA/600/R-08/021
                                                           October 2008
                Risk-Based  Criteria to
Support Validation  of Detection  Methods
            for  Drinking Water and Air
                              Prepared by
              Margaret MacDonell, Maryka Bhattacharyya, Molly Finster, Megan Williams,
                     Kurt Picel, Young-Soo Chang, and John Peterson
                         Environmental Science Division
                   U. S. Department of Energy Argonne National Laboratory
                           In collaboration with
                Femi Adeshina (Project Officer) and Cynthia Sonich-Mullin (Director)
                      National Homeland Security Research Center
               U.S. Environmental Protection Agency Office of Research and Development

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                        Disclaimer
                        The U.S. Environmental Protection Agency through its Office of Research and
                        Development funded and managed the research described here. It has been subjected
                        to the Agency's review and has been approved for publication. Note that approval
                        does not signify that the contents reflect the views of the Agency nor does it constitute
                        endorsement.
II

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Executive Summary
This report was prepared to support the validation of analytical methods for threat
contaminants under the U.S. Environmental Protection Agency (EPA) National Homeland
Security Research Center (NHSRC) program. It is designed to serve as a resource for certain
applications of benchmark and fate information for homeland security threat contaminants.

The report identifies risk-based criteria from existing health benchmarks for drinking water
and air for potential use as validation targets. The focus is on benchmarks for chronic public
exposures. The priority sources are standard EPA concentration limits for drinking water
and air, along with oral and inhalation toxicity values. Many contaminants identified as
homeland security threats to drinking water or air would convert to other chemicals within
minutes to hours of being released. For this reason, a fate analysis has been performed
to identify potential transformation products and removal half-lives in air and water so
appropriate forms can be targeted for detection over time.

The risk-based criteria presented in this report to frame method validation are expected
to be lower than actual operational targets based on realistic exposures following a release.
Note that many target criteria provided in this report are taken from available benchmarks
without assessing the underlying toxicological details. That is, although the relevance
of the chemical form and analogues are evaluated, the toxicological interpretations and
extrapolations conducted by the authoring organizations are not. It is also important to
emphasize that such targets in the current analysis are not health-based advisory levels to
guide homeland security responses.

This integrated evaluation of chronic public benchmarks and contaminant fate has
identified more than 200 risk-based criteria as method validation targets across numerous
contaminants and fate products in drinking water and air combined. The gap in directly
applicable values is considerable across the full set of threat contaminants, so preliminary
indicators were developed from other well-documented benchmarks to serve as a starting
point for validation efforts. By this approach, at least preliminary context is available for
water or air, and sometimes both, for all chemicals on the NHSRC list that was provided
for this evaluation. This means that a number of concentrations presented in this report
represent indirect measures derived from related benchmarks or surrogate chemicals, as
described within the many results tables provided in this report.

The main findings of this evaluation to identify risk-based method validation targets are
as follows:
    1.  Chronic benchmarks provide a useful basis for some low risk-based targets for
       analytical methods. Directly applicable, contaminant-specific public benchmarks for
       drinking water and air are somewhat limited across the entire suite of contaminants.
       Coverage is complete for the 15 radionuclides and about half the chemicals.
    2.  This report provides benchmarks for surrogates or fate products, as well as route-
       related benchmarks. Food residue limits for several pesticides and safety levels
       for biological contaminants in foods contribute to further coverage. A risk-based
       chronic exposure concentration is available in at least one medium for a majority
       of the threat contaminants. This also applies to the direct benchmarks, with more
       targets available for water than for air.
                                                                                                         Ill

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                             3-   A fate analysis is essential to understanding the identity and timing of relevant
                                degradation products that would form in water and air, so validation targets can also
                                be identified for those compounds posing legitimate concern.
                             4.  For chemicals lacking chronic public benchmarks, workplace limits for long-term
                                exposures can be considered for context, prioritizing those that are explicitly health-
                                based.
                             5.  For chemicals lacking both chronic public and occupational benchmarks,
                                depending on the contaminant and data available, information from acute exposure
                                guidelines (usually derived from a level of health effect) can be compared with other
                                guides and relative toxicity information to develop bounding context for method
                                validation.
                             6.  Preliminary context is provided for method validation in at least one medium
                                for all threat chemicals in the NHSRC list by integrating information on related
                                benchmarks, relative toxicity, and fate. One step that can be taken to address
                                benchmark gaps across media is to evaluate  the toxicity data for these contaminants,
                                including the data underlying existing benchmarks. In addition, benchmark
                                estimates should be revised to include toxicity from dermal exposure when
                                supportive data exist.
                             7-  A key gap for fate information is the identification of radical oxidation products in
                                air. Although half-lives have been measured or can be generally estimated, specific
                                identities are often missing. This gap limits the determination of benchmarks for a
                                number of specific fate products in air that might pose health concerns.
                             8.  For toxicity  gaps, no-observed-adverse-effect levels to support chronic benchmarks
                                are lacking for a number of chemicals, as are quantitative considerations of
                                sensitive subgroups within many existing benchmarks. To fill such gaps, downward
                                adjustments can be applied to account for uncertainty.
                             9-  This report provides information useful in streamlining and prioritizing method
                                validation and health-based evaluations. Fate, relative toxicity, and method limits are
                                considered.

                         In addition, the report identifies eight areas for future study.

                         In summary, health-based information provides a crucial foundation for validation of
                         analytical methods. Gaps identified in this study can help frame research and development
                         for analytical methods as well as  related fate and toxicity analyses. Combining information
                         on fate, benchmarks, toxicity, and analytical methods strengthens the validation effort as
                         well as other ongoing health-related research within NHSRC.
IV

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Table of Contents
Figures	v
Text Boxes	vi
Tables	vii
Acronyms and Abbreviations	viii
Chemical-Specific Notation	xii
Acknowledgements	xv
1 Introduction	1
2 Contaminants and Exposure Routes Evaluated	3
3 Methodology	7
  3-1 Evaluation Process	7
  3-2 Calculational Approach	8
4 Results	11
5 Summary and Discussion	53
  5.1 Fate Products	53
  5.2 Benchmark and Method Coverage	59
6 Findings	61
7 References	65
Appendix A: Supporting Details for Overall Approach and
           Key Benchmarks	77

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                       Figures
                       Al   Fate Evaluation to Identify Associated Chemicals for Detection
                            Consideration, and Overview Benchmark Check	78
                       A2   Example Evaluation Process for Chronic Concentrations	79
VI

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Text  Boxes
1    Report Objectives	1
2    Threat Contaminants Reviewed	3
3    Shading for Persistence as Represented by Physical-Chemical Half-Life... 12
4    Chemicals in NHSRC List or SAM Report Without Chronic
     Public Benchmarks	56
5    Solubility and Volatility Indicators for Chemicals in Water	58
                                                                                         VII

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                          Tables
                          1     Contaminants With Risk-Based Criteria (Direct or Indirect)	5
                          2     Tables of Contaminant-Specific Information	6
                          3     Key Types of Criteria and Dose Benchmarks for Air and
                                Drinking Water	7
                          4     Contaminants Represented in Air and Drinking Water	11
                          5     Risk-Based Criteria for the Initial Priority Chemicals and Their
                                Key Transformation Products in Air	13
                          6     Risk-Based Criteria for Additional Chemical Agents and Their
                                Key Transformation Products in Air	22
                          7     Risk-Based Criteria for the Initial Priority Chemicals and Their
                                Key Transformation Products in Water	26
                          8     Risk-Based Criteria for Additional Chemical Agents and Their
                                Key Transformation Products in Water	36
                          9     Risk-Based Criteria for Additional Industrial Chemicals and Products
                                in Water and Air	41
                          10    Nuclear Decay Data for Primary Radionuclides and Potentially
                                Important Radioactive Progeny	50
                          11    Risk-Based Criteria for Primary Radionuclides in Water and Air	52
                          12    Summary of Risk-Based Criteria as Analytical Method Validation
                                Targets for Water and Air	54
                          Al    Overview Description of Criteria and Dose Benchmarks for
                                Drinking Water	80
VIM

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 Acronyms  and Abbreviations
Below are acronyms and abbreviations not specific to individual chemicals. The
subsequent list provides Chemical-Specific Notation. (Additional terms used in
appendices are defined there.)

AAL       acceptable ambient level (States of New York and Rhode Island)
ACGIH    American Conference of Governmental Industrial Hygienists
AEGL     acute exposure guideline level (NAS NAC)
AEL       airborne exposure limit (CHPPM and CDC)
ANSI      American National Standards Institute
AREL      acute reference exposure level (Cal/EPA OEHHA)
AT        averaging time
atm        atmosphere(s)
ATSDR    Agency for Toxic Substances and Disease Registry (DHHS)
BW        body weight
C.         concentration of chemical i
Cal/EPA    California Environmental Protection Agency
CAS RN    Chemical Abstracts Service Registry Number (American Chemical Society)
CDC      Centers for Disease Control and Prevention (DHHS)
CEGL     continuous exposure guidance level (DoD U.S. Navy and NAS)
CF        conversion factor
CHPPM    Center for Health Promotion and Preventive Medicine (DoD U.S. Army)
Ci         curie (s)
CLP       Contract Laboratory Program (EPA)
CREL     chronic reference exposure level, inhalation (Cal/EPA OEHHA)
CVAFS     cold vapor atomic fluorescence spectrometry
d          day(s)
DHHS     U.S. Department of Health and Human Services
DHS      U.S. Department of Homeland Security
DoD      U.S. Department of Defense
DOE      U.S. Department of Energy
DOWS     Department of Water Supply (Maui County, HI)
DWEL     drinking water equivalent level (EPA)
DWLOC   drinking water level of comparison (EPA)
DWUR    drinking water unit risk
EC        electron capture
ED        exposure duration
EF        exposure frequency
EML      Environmental Measurements Laboratory (DHS)
EMSL     Environmental Monitoring Systems Laboratory
EPA       U.S. Environmental Protection Agency
ERMA     Environmental Risk Management Authority (New Zealand)
FID        flame ionization detector
f          fiber(s)
FSANZ    Food Standards Australia New Zealand
                                                                                              IX

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g           gram(s)
GC         gas chromatography
GPL        general population limit (CHPPM and CDC)
HA         health advisory (EPA)
HPLC      high performance liquid chromatography
HQ        hazard quotient
hr          hour(s)
\i           intake of chemical i
ICP         inductively coupled plasma
IO         inorganic
IR         intake rate (ingestion or inhalation)
IRED       interim reregistration eligibility decision (EPA)
IRIS        Integrated Risk Information System (EPA, electronic database)
ISO         International Standards Organization
IT         isomeric transition
IUR        inhalation unit risk
kg          kilogram (s)
KH         Henry's law constant
L           liter(s)
Ibs         pounds
LOAEL     lowest observed adverse effect level
M          million (e.g., Mf/L for million fibers/liter)
m3         cubic meter(s)
MAK       maximale arbeitsplatz konzentration (German occupational limit)
MCL       maximum contaminant level (EPA)
MD        multidetector detection
MDCH     Michigan Department of Community Health
MDL       method detection limit
MEG       military exposure guideline (CHPPM)
MeV        million electron volts
mg         milligram (s)
mg/kg-d     milligram(s) per kilogram per day
mg/L       milligram(s) per liter
min         minute(s)
mL         milliliter(s)
ML         minimum level (of quantitation)
mo         mo nth (s)
MOE       margin of exposure
MRL       minimal risk level (ATSDR)
MResL      maximum residue limit (NZFSA)
MS         mass spectrometry
MW        molecular weight
NAAQS     National Ambient Air Quality Standard(s) (EPA)
NAC       National Advisory Committee (NAS,  for AEGLs)
NAS        National Academy of Sciences
NCEA      National Center for Environmental Assessment (EPA)
NERL      National Exposure Research Laboratory (EPA)

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NESHAPs   National Emission Standards for Hazardous Air Pollutants (EPA)
NHSRC    National Homeland Security Research Center (EPA)
NIOSH     National Institute for Occupational Safety and Health (DHHS)
nm         nanometer(s) (one-billionth meter)
NOAEL    no observed adverse effect level
NYSDEC   New York State Department of Environmental Conservation
NZFSA     New Zealand Food Safety Authority
OAQPS     Office of Air Quality Planning and Standards (EPA)
OEHHA    Office of Environmental Health Hazard Assessment (Cal/EPA)
OEL        occupational exposure limit
OPP        Office of Pesticide Programs (EPA)
OPPT      Office of Pollution Prevention and Toxics (EPA)
OPPTS     Office of Prevention, Pesticides, and Toxic Substances (EPA)
ORD       Office of Research and Development (EPA)
OSHA      Occupational Safety and Health Administration
PEL        permissible exposure limit (OSHA)
PCM       phase contrast microscopy
pH         negative logarithm of the hydrogen ion concentration (in solution)
pCi         picocurie(s)
PPRTV     provisional peer reviewed toxicity value (EPA)
PUF        polyurethane foam
QAP        Quality Assessment Program
RED        reregistration eligibility document (EPA)
REL        recommended exposure limit (NIOSH)
RfC        reference concentration
RfD        reference dose
SAM        Standardized Analytical Methods (report)
sec         second (s)
SF          slope factor
SF          spontaneous fission
SI          International System of Units
SM         standard method
SOW       statement of work
SVOCs     semivolatile  organic compounds
SW         solid waste
TEL        tolerable exposure limit (NZERMA)
TEEL       temporary emergency exposure limit (DOE)
TEM       transmission electron micrsoscopy
TIC        toxic industrial chemical
TLV        threshold limit value (ACGIH)
TO         toxic organics
TS         thermospray
USDA      U.S. Department of Agriculture
UF         uncertainty factor
ug          microgram(s)
ug/L        microgram(s) per liter
ug/m3       micrograms(s) per cubic meter
                                                                                                    XI

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                           UR         unit risk
                           UV         ultraviolet
                           WIDHFS   Wisconsin Department of Health and Family Services
                           wk          week(s)
                           yr           year(s)
XII

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Chemical-Specific  Notation
This chemical-specific list is offered as a resource for agent codes and basic chemical
names and to indicate potential relationships among various threat chemicals and
selected fate products (noted in italics). This information is intended to be illustrative,
not inclusive. That is, not all terms defined in the text or tables are included here, nor are
all fate relationships.

AC      hydrogen cyanide (chemical formula HCN)
ACH    alphachlorohydrin, or 3-chloro-l,2-propanediol
As       arsenic (component of fate products of arsine; lewisites-1,2;
         ethyldichloroarsine)
BTEX   benzene, toluene, ethylbenzene, xylene (representative gasoline components)
CK      cyanogen chloride (can form from natural humics and cyanide with
         chloramine)
C12      chlorine gas
CN      cyanide (also used to refer to the tear gas form, acetophenone)
CO      carbon monoxide (fateproduct ofdichlorvos, HCN, phorate, carbon
         disulf.de, others)
CO2     carbon dioxide (fateproduct of chloropicrin, CK, HCN, PFIB,
         phosgene, others)
COC    ether group (C-O-C)
CS      tear gas, 2-chlorobenzylidene malonitrile
         (note:  tear gas form CN is acetophenone)
CVAA   2-chlorovinylarsonous acid (fateproduct oflewisite-1)
CX      phosgene oxime, or hydroxy carbonimidic dichloride
DESH   diisopropyl ethyl mercaptoamine (fateproduct ofVX)
DIMP   1,2-diisopropyl methylphosphonate (by-product ofsarin synthesis)
DMP    dimethyl phosphite (fateproduct ofTMP)
DPD    n,n-diethyl-p-phenylene diamine
EA2192 S-[2-(diisopropylamino)ethyl] methylphosphonothioate  (fateproduct of VX)
ECH    epichlorohydrin
ED      ethyldichloroarsine
EEPA    O-ethyl ethylphosphonothioic acid (fateproduct ofVE)
EMPA   O-ethyl methylphosphonic acid (fateproduct ofGE, VM, VX, Vx)
EMPTA O-ethyl methylphosphonothioic acid (fate product ofVX)
ETO    ethylene oxide
F        fluoride (forfate product information, see HF below)
F2       fluorine (sometimes combined with soluble fluoride, for benchmarks)
FM      titanium tetrachloride
FNA    fuming nitric acid
GA      tabun; O-ethyl A^TV-dimethylphosphoramidocyanidate
GB      sarin; O-isopropyl methylphosphonofluoridate
GD      soman; O-pinacolyl methylphosphonofluoridate
GE      ethyl sarin; ethyl GB; O-isopropyl ethylphosphonofluoridate
GF      cyclosarin; cyclohexyl sarin; O-cyclohexyl methylphosphonofluoridate
                                                                                                   XIII

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                            H

                            HAA
                            HC1

                            HCN
                            HD
                            HF

                            Hg
                            HN-2
                            HOC1
                            HOCN
                            H3P°4
                            H2S
                            H2S04
                            HT

                            IMPA
                            L(L1)
                            L-2
                            L-3
                            LO
                            MPA
                            NaCN
                            NH-2
                            NH3
                            NO

                            NO2

                            NO3
                            03
                            OH
                            P
                            PAH(s)
                            PCB(s)
                            PCP
                            PFIB
                            PH3
                            P04
                            PS
                            PTFE
                            RP
                            SA
                            SEE
                            SO,
sulfur mustard (undistilled HD); di-2 chloroethyl sulfide,
bis(2-chloroethyl) sulfide
haloacetic acid (includes dichloroacetic acid, fate product ofdichlorvos)
hydrochloric acid/hydrogen chloride (fateproduct of chloropicrin,
CK, ED, FM,  lewisites-1/2, nitrogen mustard, others)
hydrogen cyanide (agent AC) (fateproduct ofGA)
distilled sulfur mustard (same CAS number as sulfur mustard, H)
hydrofluoric acid/hydrogen fluoride (fateproduct of
GB, GD, GE, GF, PFIB,
mercury
nitrogen mustard-2 (also NH-2), or bis(2-chloroethyl)methylamine
hypochlorous acid (chlarination residual often found in drinking water)
cyanic acid (fate product of cyanogen chloride)
phosphoric acid (fate product of agents GA, RP, VG, and many pesticides)
hydrogen sulfide (fate product ofphorate)
hydrogen sulfate, sulfuric acid (fate product ofphorate)
sulfur mustard-T mixture; mixture of sulfur mustard
(see above) andT, which is bis[2-(2 chloroethylthio)ethyl] ether
O-isopropyl methylphosphonic acid (fate product ofGB)
lewisite-1; dichloro(2-chlorovinyl)arsine; 2 chlorovinyldichloroarsine
lewisite-2; bis(2-chlorovinyl)chloroarsine
lewisite-3; tris(2 chlorovinyl)arsine
lewisite  oxide (fate product of lewisite)
methylphosphonic acid (fate product of GB,  GD, GE, GF, VM, VX, Vx)
sodium cyanide (representative cyanide salt)
nitrogen mustard-2 (also HN-2); or bis(2-chloroethyl)methyl amine
ammonia (fate product of cyanogen chloride, HCN)
nitric (nitrogen) oxide (fate product of chloropicrin, HCN, diesel,
NO j others)
nitrogen dioxide, nitrite (fate product of chloropicrin, cyanogen
chloride, HCN)
nitrate (fate product of chloropicrin, cyanogen chloride, HCN)
ozone (fate product of chloropicrin)
hydroxide, hydroxyl radical
para (e.g., p-nitrophenol, fate product of methyl parathion)
polycyclic aromatic hydrocarbon(s)
polychlorinated biphenyl(s)
phencyclidine (also  referred to as angel dust)
perfluoroisobutylene
phosphine (fate product of red phosphorus)
phosphate (for fate product information, see H3PO4 above)
chloropicrin
polytetrafluoroethylene (also referred to as Teflon)
red phosphorous
arsne
staphylococcal enterotoxin B
sulfate
XIV

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T2       trichothecene (mycotoxin)
TDG     thiodiglycol (fate product of sulfur mustards H/HD and HT)
TEPP     tetraethyl pyrophosphate
TiQ4     titanium tetrachloride
TMP     trimethyl phosphite
VE       O-ethyl-S-[2-(diethylamino)ethyl] ethylphosphonothioate (also as "thiolate")
VG       O,O-diethyl-S-[2-(diethylamino)ethyl] phosphorothioate (also as "thiolate")
VM      O-ethyl-S [2-(diethylamino)ethyl] methylphosphonothioate (also "thiolate")
VX       O-ethyl-S [2-(diisopropylamino)ethyl] methylphosphonothioate
          (also as "thiolate")
Vx       O-ethyl-S-[2-(dimethylamino)ethyl] methylphosphonothioate
          (also as "thiolate")
WP      white phosphorus (comprises up to 0.2% of RP, same CAS number)
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Acknowledgements
The authors wish to express their deep appreciation to many colleagues who contributed
to the development of this report, including Chandrika Moudgal, Alan Weinrich
and Deborah McKean of EPA; and Shanna Collie, Andrew Davidson, Lynne Haroun,
Kelley Swanberg, Jennifer Mattler, Kathleen Mettel, Camarie Perry, Allison Jenkins,
Melissa Liu, Jerusha Sparks, and Shirley Williams-Scott of the Argonne team. Their
inputs and insights have been invaluable.
XVI

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             Introduction
This report was prepared to support the validation of analytical methods for threat
contaminants under the U.S. Environmental Protection Agency (EPA) National
Homeland Security Research Center (NHSRC) program. Its purpose is to identify risk-
based criteria from existing health benchmarks for drinking water and air for potential
use as validation targets.
    The focus is on benchmarks for chronic public exposures. The priority sources
are standard EPA concentration limits for drinking water and air, along with oral and
inhalation toxicity values.
                       Report Objectives (Box 1)
 1. Identify health-based benchmarks for contaminants identified as potential chemical and
 radiological threats for use in defining potential target concentrations for validating analytical
 methods
 2. Assess the fate and persistence of these threat contaminants to identify other chemicals that
   could form in water and air, and identify potential benchmarks for them
    Many contaminants identified as homeland security threats to drinking water or
air would convert to other chemicals within minutes to hours of being released. For this
reason, a fate analysis has been performed to identify potential transformation products
and removal half-lives in air and water so appropriate forms can be targeted for detection
over time. The role of this analysis is reflected in Box 1.
    The risk-based criteria presented in this report to frame method validation are
expected to be lower than actual operational targets based on realistic exposures following
a release. Note that many target criteria provided in this report are taken from available
benchmarks without assessing the underlying toxicological details. That is, although
the relevance of the chemical form and analogues are evaluated,  the toxicological
interpretations and extrapolations conducted by the authoring organizations are not.
    It is also important to emphasize that such targets in the current analysis are not
health-based advisory levels to guide homeland security responses.

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    This report is designed to serve as a resource for certain applications of benchmark
and fate information for homeland security threat contaminants. It is organized as
follows:
    •  Chapter 2 identifies the threat contaminants and exposure routes considered.
    •   Chapter 3 describes the evaluation process, including the approach for
       calculating target criteria from benchmarks given in other measures such as
       doses.
    •  Chapter 4 provides benchmark and criteria results for air and water in
       companion tables organized by contaminant set and medium; fate notes are
       given for two key sets.
    •  Chapter 5 summarizes results and discusses how they can be applied, considering
       target criteria, fate processes and products, relative toxicities, and benchmark
       coverage.
    •  Chapter 6 presents overall findings and next steps.
    •  Appendix A illustrates the general process for identifying risk-based criteria to
       help  guide detection validation.

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           Contaminants and Exposure
            Routes Evaluated
    To frame analytical method development efforts as part of NHSRC program
planning, NHSRC identified more than 100 contaminants as possible threats. The
list included toxic industrial chemicals, chemical warfare agents, and radionuclides. A
related list to support the validation of analytical methods contained 23 chemicals, split
between industrial toxics and agents. Method validation targets for this set were the
driver for this report.
Threat Contaminants Reviewed (Box 2)
Contaminants
chemicals: chemical warfare agents and
toxic industrial chemicals
more chemical agents
more industrial chemicals
radionuclides
remaining chemicals or groups (classes
or mixtures)
Source
Method Validation priority list
NHSRC list and the recent EPA report on standardized
analytical methods (SAM)
NHSRC list
NHSRC list and 2007 SAM report
SAM report
    Standard health-based benchmarks address two main exposure routes:  inhalation
and ingestion. Where the value accounts for other exposures such as dermal absorption,
those contributions are incorporated into the target concentrations presented here.
Benchmarks were evaluated in phases for the contaminant sets shown in Box 2 and
Table 1 (specific contaminants are listed in Table 2).
    The Standardized Analytical Methods (SAM) document (EPA 2008) reviews
analytical methods for chemicals (including nonspecific mixtures: asbestos,
polychlorinated biphenyls [PCBs], and kerosene), plus general chemical groups, as well
as radionuclides, pathogens, and biotoxins. The SAM (EPA 2008) was reviewed to
identify any additional  contaminants not already addressed as either a primary threat or
associated fate product  from the NHSRC list in order to assess benchmarks to support
validation targets for them. This review identified additional candidates for  assessment.
Most chemicals in the SAM report are also on the NHSRC list, and many of the
additional compounds  are fate products (already assessed) or precursors or impurities of
those chemicals. This commonality illustrates the integration of the specified program,
with core threat contaminants and associated chemicals being addressed
across complementary projects.
    Regarding the general chemical groups, the SAM report is organized by method
type, so in some instances only a basic category is indicated. These five groups are
diesel range and gasoline range organic compounds, volatile and semivolatile organic
compounds (SVOCs),  and metals not otherwise specified. Each covers an extensive
set of chemicals.

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    For example, gasoline range organics cover hundreds of hydrocarbons that include
alkanes, alkenes, and aromatic compounds like benzene, toluene, ethylbenzene, and
xylene (BTEX). These last four chemicals (BTEX) were selected to represent gasoline in
this report, together with n-hexane. For diesel-range organic compounds, benchmarks
found for diesel exhaust are given in this report. For the other three general groups, a
number of specific chemicals within those categories are already being evaluated, so they
are not addressed further.
    Table 1 identifies the sets of primary contaminants for which relevant risk-based
criteria were assessed; several are represented by indirect benchmarks. Additional
chemicals beyond those listed were also assessed, as reflected in Table 2.

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Table  1  Contaminants With Risk-Based Criteria (Direct or Indirect)3
       23 Priority Chemicals
        'detection Validatioi
 Chloropicrin
                                                                icmical
            Agents
            C List am
Arsine (SA)
     18 Additional
 Industrial Chemic
     'NHSRC L'  N
Aldicarb (Temik)
        .5 Radionuclides
       (NHSRC List and
Americium-241
 Dichlorvos
Cyanogen chloride (CK)
Boron trichloride
Californium-252
 Dicrotophos (Bidrin)
Cyclohexyl sarin (GF)
Boron trifluoride
Cesium-137
 Dimethyl phosphite (DMP)
Ethyl sarin (GE)
Bromadiolone
Cobalt-60
 Ethyldichloroarsine (ED)
Hydrogen cyanide (HCN, agent AC)
Cadmium
Curium-244
 Fenamiphos
Mustard, nitrogen (HN-2/NH-2)
Carbofuran
Europium-154
 Lewisite (L-l)
Perfluoroisobutylene (PFIB)
Carbon disulfide
Iridium-192
 Lewisite 2 (L-2)
Red phosphorus (RP)
Chlorine
Plutonium-238
 Lewisite 3 (L-3)
Tear gas (CS)
Cyanide salts as sodium
cyanide
Plutonium-239
 Methyl parathion
Titanium tetrachloride (FM)
Ethylene oxide (Oxirane)
Polonium-210
 Mevinphos (Phosdrin)
VE
Fluorine
Radium-226
 Mustard, sulfur (H)
VG
Furan
Ruthenium-103
 Mustard, sulfur, distilled (HD, distilled H)
VM
Mercuric chloride
Ruthenium-106
 Mustard, sulfur with T (HT)
Vx
Nitric acid (fuming)
Strontium-90
 Nicotine
                                    Oxamyl (Vydate)
 Phorate (Thimet)
                                    Paraquat
 Sarin (GB)
                                    Sodium fluoroacetate
                                    (fluoroacetate salt)
                              Uranium-238
                                16 Additional Industrial
                                         Chemicals
                                       (SAM report)
 Soman (GD)
 Strychnine
 Tabun (GA)
 Tetraethyl pyrophosphate (TEPP)
 Trimethyl phosphite (TMP)
 VX
 This set includes several chemical
 warfare agents from the earlier, larger
 NHSRC list that are also in the SAM
 report. Similarly, agents CS, FM, GE,
 PFIB, RP, VF, VG and VM are also
 on the larger NHSRC list as well as
 in the SAM report. Vx was included
 as a V-series nerve agent, and nitrogen
 mustard was included for similarity to
 the H agents.

 Two others from the earlier NHSRC
 list, phosgene oxime (agent CX) and
 Teflon (polyterafluoroethylene or
 PTFE), are not in the SAM report,
 so they were not evaluated further in
 this report.

 (Note that some agents such as HCN
 also have industrial applications; VG
 has ako been used as apesticide, while
 the pesticide chlaropicrin was formerly
 agent PS.)
Sulfur dioxide
Some primary contaminants
on the NHSRC list are also fate
products of chemicals already
covered as priority compounds
or additional chemical agents.

These include ammonia;
arsenic; formaldehyde;
hydrogen chloride, fluoride, and
sulfide; nitric acid and nitrogen
dioxide; phosgene, phosphine;
and hydrogen sulfatelsulfuric
acid.

Benchmarks for those chemicals
are identified within the tables
for the first two contaminant
sets, so they are not repeated as
main chemicals within this set.
Allyl alcohol
Asbestos
1,2-Dichloroethane (ethylene
dichloride)
Diesel engine exhaust
1,2-Diisopropyl methylphosphonate
(DIMP)
1,4-Dithiane (diethylene disulfide)
                                                                                                           Gasoline range organics: see 5 noted
                                                                                                           below
                                                                                                           Kerosene
                                                                                                           Methyl isocyanate
                                                                                                           Phenol
                                                                                                           Polychlorinated biphenyls (PCBs)
                                                                                                           Propylene oxide
                                                                                                           Gasoline is represented by benzene, toluene,
                                                                                                           ethylbenzene, xylenes, and n-hexane.
                                                                                                           Two above are linked to chemical agents:
                                                                                                           DIMP is a by-product ofGB synthesis
                                                                                                           andl,4-dithianeis linked to munitions
                                                                                                           production and storage and thermal
                                                                                                           degradation of sulfur mustards.
    a For chemical agents (in blue) indicators values for ED and nitrogen mustard represent fate products. For toxic industrial chemicals (in purple), the TEPP is represented by
a fate product; remaining additional industrial chemicals from the SAM report not already accounted for by the NHSRC list or its key fate products are also provided. Chronic
occupational levels exist for many of these and other chemicals for which no public benchmarks were found. Information is available to frame method validation across all chemical
and radiological contaminants from NHSRC and SAM sets.

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Table 2  Tables of Contaminant-Specific Information3
 Table
Focus
Medium
Contaminants Evaluated
Report Body
5
6
7
8
9
10
11
12
Criteria for public
Criteria for public
Criteria for public
Criteria for public
Criteria for public
Properties, decay products
Criteria for public
Criteria for public
Air (inhalation)
Air (inhalation)
Drinking water (oral)
Drinking water (oral)
Both air and drinking water
Both air and drinking water
Both air and drinking water
Both air and drinking water
23 initial priorities in air plus many fate products
14 remaining agents in air plus many fate products
23 initial priorities in water plus many fate products
14 remaining agents in water plus many fate products
more industrial chemicals
1 5 radionuclides plus radioactive progeny
15 radionuclides
threat contaminants and products combined
    a      indicates the table is for air, blue indicates water, and green indicates both. Shading for contaminant type matches that used in Table 2.

   Threat contaminants are those on the NHSRC list or in the Standardized Analytical Methods (SAM) report (EPA 2007a), and they are considered the primary
contaminants for this study (These are distinguished from fate products not specifically identified in the SAM report or NHSRC list.)
   Fate notes are included in the basic results table for priority compounds and additional chemical agents (Tables 5—8) because these groups are evaluated first as a
main foundation for this report. Additional fate information highlighted in Chapter 5 (Table 13) covers these and most of the other chemicals.

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             Methodology
This section describes the overall evaluation process and specific calculations used to
identify target criteria in air and water for method validation. The process is discussed in
Section 3-1, and calculational details are presented in Section 3-2.

3.1   Evaluation Process
Three steps were involved in identifying the Risk-Based Criteria for validation targets:
    1. Assess the fate and persistence of the threat contaminants to identify others
       likely to form if the parent were released to air or water, considering various
       transformation processes.
    2. Identify concentration benchmarks relevant to the general public for these
       contaminants.
    3- Identify dose benchmarks and derive concentrations.
    These steps are illustrated in Appendix A, and key available benchmarks are listed in
Table 3- More details for several drinking water benchmarks are provided in Appendix A.

Table 3  Key Types of Concentration and Dose Benchmarks
          for Air and Drinking Water3
Medium Orgzn. Benchmark
Air
Air
Air
Air
Air
Air
Air
Water
Water
Water
Water
Water
Water
Water
Water
EPA
EPA
EPA
CDC
ATSDR
Cal/EPA
NAS-NAC
EPA
EPA
EPA
EPA
EPA
ATSDR
CHPPM
ERMA
RFC: reference concentration (noncancer)
IUR inhalation unit risk (cancer)
NAAQS: national ambient air quality standard
PPRTV: provisional peer-reviewed toxicity value
AEL GPL: airborne exposure limit,
general population limit
MRL: minimal risk level
CREL: chronic reference exposure level
AEGL: acute exposure guideline level
RfD: reference dose (noncancer);
SF, (unit risk) UR slope factor; drinking water
(DW)UR
PPRTV: provisional peer-reviewed toxicity value
MCL: maximum contaminant level
HA: health advisory (lifetime; also 10 day [d], 1 d)
DWEL: drinking water equivalent level
MRL: minimal risk level
MEG: military exposure guideline
TEL: tolerable exposure limit
Application
General public, repeat-chronic exposures
General public, repeat-chronic exposures
General public, repeat-chronic exposures
General public for 24/7, multiple consecutive years
General public, acute, intermediate, chronic
General public, repeat-chronic exposures
General public, single exposures up to 8 hr
(for emergency response)
General public, repeat-chronic exposures
General public, repeat-chronic exposures
General public, repeat-chronic exposures
General public, repeat-chronic exposures
General public, repeat-chronic exposures
Military personnel, can be intake-adjusted
Military personnel, can be intake-adjusted (from 5 or
1 5 L/d to 2 L/d) for relevance to public
General public, repeat-chronic exposures
   a ASTDR = Agency for Toxic Substances and Disease Registry, within CDC; Cal/EPA = California EPA; CDC = Centers for Disease Control and
Prevention; CHPPM = U.S. Army Center for Health Promotion and Preventive Medicine; ERMA = New Zealand Environmental Risk Management Authority;
NAS-NAC = National Academy of Sciences-National Advisory Committee (for AEGLs). Other limits evaluated include the Navy and NAS continuous exposure
guidance levels (CEGLs) for adults in submarines for 90 days.

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                           Key available benchmarks are listed in Table 3-

                           The toxicity values were assessed according to the recommended EPA (2003a) hierarchy:
                               1.  EPA Integrated Risk Information System (IRIS) values (These toxicity values
                                  exist for a number of chemicals and routes, as a primary source for air and water
                                  benchmarks.)
                               2.  EPA provisional peer-reviewed toxicity values (PPRTVs) (For direct chronic
                                  benchmarks, no unique values were found in the initial review.)
                               3-  All other values, including from regional, state, and international sources.

                           When multiple benchmarks are found, other values are also provided  to offer further
                           context. The emphasis is on EPA benchmarks that reflect the most recent analyses.

                           3.2  Calculational Approach
                           The approach for calculating target concentrations from established toxicity values is
                           described in this section. The  objective is to ensure transparency for the risk-based values
                           presented in the report, so the calculations can be readily followed. For benchmarks
                           given as doses rather than concentrations, the process involves combining an estimate
                           of the intake or dose from the assumed repeat exposures over an extended time with an
                           estimate of the associated toxicity for that chemical by the given route of exposure, such
                           as ingestion of drinking water.
                               The intake for an individual can be calculated using the following equation  (from
                           EPA 1989):

                         C,- x ffi. x EF x ED     .         ,    _^   .
                   I =  	    (may apply a CF, where needed to adjust mass units)
                              BWxAT

                               where:
                                 L   =   intake of chemical i milligram(s) per kilogram per day (mg/kg-d)
                                 C   =   concentration of chemical i in water microgram(s) per liter (ug/L) or air
                                         microgram(s) per cubic meter (ug/m3)
                                 IR  =   intake (ingestion or inhalation) rate, assumed to be 2 L water/d,
                                         or 20 cubic meters (m3) air/d
                                 EF  =   exposure frequency, assumed to be 365 d/yr
                                 ED =   exposure duration, assumed to be 30 yr
                                 BW=   body weight kilogram (kg), assumed to be 70 kg (adult)
                                 AT =   averaging time (in d): 10,950 d  for noncancer effects; 25,550 d
                                         for cancer risk
                                 CF =   conversion factor, as indicated for a  given calculation (e.g., 103
                                         microgram per milligram [ug/mg])

                               (Note that exposure time is included with intake rate.) An ED of 30 years was used
                           because it is generally assumed for contaminated sites.

                               The intake is combined with a route-specific toxicity value (e.g., from EPA IRIS or
                           a PPRTV, or another source such as a dose value developed  for the U.S. Army) to assess
                           the potential for a noncancer effect or the probability of incurring cancer over a lifetime
8

-------
as a result of that exposure. Certain chemicals are considered to cause both cancer and
noncancer effects, and toxicity can be indicated for oral or inhalation exposure or both.
As determined from these toxicity data, chemical- and route-specific values have been
developed to assess potential effects from these exposures.
                                                 Tntalce
  Noncancer hazard quotient (HQ) =	;	, or I/RfD.
                                           Reference dose

    The potential for noncancer or cancer effects is evaluated by combining the toxicity
value with the estimated intake, as follows (EPA 1989):

        Cancer risk = Intake x Slope factor, or I x SF.

    Intakes were initially estimated for both oral and inhalation exposures, such that
these equations applied to both routes. However, inhalation toxicity values are now
expressed as concentrations (e.g., mg or ug per m3 air). The reference concentration
(RfC) represents the target for noncancer effects, and the IUR level corresponding to
an incremental risk of 10~6 is the target for the cancer endpoint in this analysis. Thus,
the equations shown above are applied directly for oral exposures, and they also frame
inhalation estimates, as indicated below.
    Only oral and inhalation exposures are specifically evaluated in this report;
consideration of other routes (such as dermal absorption) has been incorporated into
some existing benchmarks, and, where indicated, those additional contributions would
be reflected in future values,  following a detailed review of relevant toxicity data. As a
note, this calculation process was needed for only a limited number of chemicals because
criteria could be determined directly from benchmark values for most. Toxicity values are
applied as follows to identify the  Risk-Based Criteria for detection validation:

To derive a target criteria for water from an oral RfD  (mg/kg-d):
    1.  Multiply the RfD by 70 kg.
    2.  Divide by 2 L/d.
    3-  To convert  milligrams per liter (mg/L) to ug/L, multiply by 1,000.

To derive a target water criteria from an oral SF (risk per mg/kg-d), for a 10~6 risk level:
    1.  Multiply 10'6 (the target risk level) by 70 kg and 25,550 d.
    2.  Divide by SF, 2 L/d, 365 d/yr, and 30 yr. (Where a risk-specific concentration  is
        given for a W6 risk, that level is used directly.)
    3-  To convert  mg/L to  ug/L, multiply by 1,000.

To convert an RfC or reference concentration to an RfD, if desired:
    1.  Divide by 70 kg.
    2.  Multiply by 20 m3/d.

    For a number of contaminants, no chronic public benchmark was found, but
various  OELs exist. Those limits are not included in the main body of the report for
two reasons. First, they apply to a different target group with exposure conditions that
differ from those being assessed, i.e., typically for adults working 8 or 10 hours a day
with evening and weekend recovery periods (although, for example, the Navy CEGLs

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                          are for continuous exposures over 3 months in a submarine). Second, although some
                          aim to be strictly health-based (such as the threshold limit values [TLVs] of the American
                          Conference of Governmental Industrial Hygienists [ACGIH]), many are not. That is,
                          implementation factors including feasibility are also considered for various Occupational
                          Safety and Health Administration (OSHA)  permissible exposure limits (PELs) and
                          National Institute for Occupational Safety and Health (NIOSH) recommended
                          exposure limits  (RELs). For example, feasibility is identified as a factor for the asbestos,
                          formaldehyde, and ethylene oxide RELs.
                              Additional  benchmarks and other data were pursued when a chronic public
                          benchmark was not found so that preliminary context for method validation could
                          be provided for all the chemicals, and radionuclides from the NHSRC list  and SAM
                          report. Thus, various OELs are presented which may suggest possible high bounds for
                          validation. These include guidelines developed for chemical agents by the U.S. Army
                          (CHPPM) to support deployed troops. Some of those values are based on  the same
                          studies used to define chronic public benchmarks, notably in drinking water. The
                          drinking water values presented in Table 2 based on the CHPPM concentrations for
                          deployed force intakes of 5 L/d are scaled to 2 L/d for the general public.
10

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             Results
Target criteria for the detection program determined from benchmarks relevant to
the general public are presented in several tables in this section. Results are organized
by chemical category and medium, as illustrated in Table 4. (Several fate products are
common across chemicals and media, and the set of unique fate products within a table
is indicated in parentheses.)
Table 4  Contaminants  Represented in Air and Drinking Water
                                                                                            Risk-Based
                                                                                              Chronic
Air
Table 5
Table 6
Table 9
Table 11
Total
Water
Table 7
Table 8
Table 9
Table 11
Total

23 priority chemicals
14 remaining agents
34 more industrials
15 radionuclides
86 primary

23 priority chemicals
14 additional agents
34 more industrials
15 radionuclides
86primary

14
8
24
15
61 in air

20
5
32
15
72 in water

54
15
1 (unique)
22
92

53
16
2
22
93

68
23
25
15
131

73
21
34
15
143
   a Several concentrations are from indirect benchmarks. Fate product subtotals include unique entries within media. To illustrate, dimethyl phosphite is both
a primary contaminant and fate product in Tables 5 and 7, and hydrogen fluoride is a fate product in both Tables 7 and 8, as one of several products associated
with more than one primary chemical. Table 12 includes more than 200 unique values covering approximately 100 chemical and radiological contaminants in air
and water combined.

    These results reflect an extensive review of contaminants  separately identified on the
NHSRC list and in the SAM report (2007a), and unique fate products identified for
these contaminants in drinking water and air. The contaminants are addressed in five
groups:
    1.  Initial priority list for method validation, split between industrial chemicals and
        agents
    2.  Remaining agents on the NHSRC list
    3-  Remaining toxic industrial chemicals on the NHSRC list
    4.  All radionuclides on the NHSRC list and in the SAM report
                                                                                                           11

-------
                                5.  Remaining industrial chemicals and groups in the SAM report
                                The overview analysis of physical-chemical fate for the contaminants in the NHSRC
                           list and SAM report identified hundreds of transformation products. Many are common
                           to multiple parents, e.g., hydrogen fluoride and arsenic are fate products of several
                           chemical warfare agents. Also, because moist air promotes hydrolysis, hydrolysis products
                           may be found in both drinking water and air.
                                Risk-based validation targets for the initial priority chemicals and the rest of the
                           chemical agents in air and water are presented  in four companion tables in the main
                           body of this report:
                                •   Table 5 — priority chemicals and key products in air
                                •   Table 6—14 additional agents and key products in air
                                •   Table 7 — 23 priorities and products in drinking water
                                •    Table 8 — 14 agents plus products in drinking water

                                Fate notes are included in these tables. Persistence indicators for air and water are
                           represented by physical-chemical half-lives, organized according to the intervals shown in
                           Box 3-
                                                             The risk-based targets for the rest of the chemicals are
                                                        presented in:
                                                        •   Table 9 — remaining industrial chemicals in water
                                                        and air
Shading for Persistence
as Represented by Physical-
Chemical Half-Life (Box 3)
Indicator
Short
Moderate
Long
Very long
Half-Life
Seconds— hours
Days— weeks
Weeks— mo nths
Months— years
                                                             Several fate products are included in this table, and
                                                        associated highlights are given in Chapter 5- Unlike
                                                        Tables 5—8, where fate products with benchmarks
                                                        are italicized and indented beneath the parents, this
                                                        combined media table is alphabetized, with parents listed
                           in parentheses following the fate products. Where no directly applicable benchmark
                           was found, parentheses are also used to indicate values conservatively represented by
                           analogues or surrogates that are more toxic. Those values are offered as indicators so
                           that a preliminary context can be provided for all primary contaminants, to help frame
                           priorities for follow-on evaluations.
12

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      Table 5 Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Chloropicrin

Phosgene

Hydrogen chloride (HCl)

Ozone (O3)

Nitrogen dioxide (NO2)

Nitric acid (HNO3)

Dichlorvos
Phosgene

Carbon monoxide (CO)
CASRN
76-06-2

75-44-5

7647-01-0

10028-15-6

10102-44-0

7697-37-2

62-73-7
75-44-5

630-08-0
Air Concn.
(l*glrr?)
0.4

0.3

20

160

100

(86)
(acute only)

0.5
0.3

10,000
Basis
OREL
(Cal/EPA)

RFC, 0.0003 mg/m3
(EPA IRIS)

RFC, 0.02 mg/m3
(EPA IRIS)

NAAQS, 0.08 ppm
(EPA Office of Air
Quality Planning
and Standards
[OAQPS])
NAAQS
(EPA OAQPS)

acute reference
exposure level
(AREL)
(Cal/EPA)
RfC
(EPA IRIS)
RfC, 0.0003 mg/m3
(EPA/IRIS)

NAAQS for CO
(EPA OAPQS)
Citation/Link for Risk-Based \alue
Cal/EPA 2005a (Noncancer Chronic Reference Exposure Levek),
http://www.oehha.org./air/chronic rels/pdf/allchrels.pdf;
this value was established in 2001 and is also summarized in Cal/
EPA 2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
EPA (2006f), http://www.epa.gov/iris/subst/0487.htm: this was also
identified as the earlier draft Cal/EPA CREL (1997) in EPA 2000a,
http://www.epa.gov/ttn/atw/hlthef/phosgene.html

EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value is lower, the CREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/ pdf77647010.pdf

EPA 1997b, http://www.epa.gov/air/criteria.html (from 1997) is
8-hr average; CREL (from 1992) is 180 micrograms/m3, Cal/EPA
2005b,
http://www.arb.ca.gov/toxics/healthval/contable.pdf

EPA 1 997b, http://www.epa.gov/air/criteria.html: note that the air
quality standard (from 1990) is the annual arithmetic mean; the
CREL is 470 ug/m3 (from 1992), in Cal/EPA 2005b,
http://www.arb.ca.gov/toxics/healthval/contable.pdf

Cal/EPA (2000), only for acute, no chronic level found,
http://www.oehha.org/air/acute rels/allAcRELs.html

EPA (1994), http://www.epa.gOV/iris/subst/0 1 5 1 .htm: also the 1997
MRL; and see EPA 2000a (OPPTS no observed adverse effect level
(NOAEL) and uncertainty factor [UP] chronic), IRIS identifies
"study NOAEL of 0.05 mg/m3" — which with 1 Ox interspecies and
intraspecies factors results in a RfC of 0.5 ug/m3
EPA (2006f), http://www.epa.gov/iris/subst/0487.htm: this was also
identified as the 1997 draft Cal/EPA CREL in EPA 2000e,
http://www.epa.gov/ttn/atw/hlthef/phosgene.html

EPA 1 997b, http://www.epa.gov/air/criteria.html: note that this
standard (from 1990) is an 8-hr average annual ceiling value
Fate Notes
Photolysis half-life is 18 hr to
20 d in simulated sunlight; forms
phosgene and nitrosyl chloride,
with rapid photolysis (3—4 min) to
atomic chlorine and nitric oxide
(NO); these free radicals form
(O3), (NO2), and chlorinated
hydrocarbons
Intermediate photolysis product,
with no direct photolysis at
>290 nanometer (nm);
atmospheric half-life estimates are
20to44to>100yr
Hydrolysis product, is incorporated
into moisture in air, subject to wet/
dry deposition

Photolysis product of intermediate
nitrosyl chloride; half-life is 7 to 30
minutes (min)

Rapidly interconverts with nitric
oxide (NO) in sunlight; can then
form nitrous and nitric acids in
moist air

Forms from NO2 in moist air;
subject to wet/dry depositioin

Atmospheric half-life is 13.6 hr;
hydroxyl radical half-life is 2 d,
main products are phosgene and
carbon monoxide (CO)
See entry under chloropicrin;
atmospheric half-life estimates
extend from 20 to > 100 yr

Can persist for several weeks, can
oxidize to CO
CO

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Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Dicrotophos
Dimethyhlmine
Methanol
Phosphoric Acid
Dimethyl phosphite (DMP or DMHP)
Methanol
Phosphoric Acid
Ethyldichloroarsine (agent ED)
Hydrogen chloride (HCl)
Arsenic, inorganic
CASRN
141-66-2
124-40-3
67-56-1
7664-38-2
868-85-9
67-56-1
7664-38-2
598-14-1
7647-01-0
7440-38-2
Air Concn
(mlnf)
Not available
(oral and
dermal
toxicant)
2
4,000
10
420
4,000
10
Basis
Lowest observed
adverse effect level
(LOAEL) of 0.02
mg/kg-d, MOE
target 300 (EPA
OPPTS) (Table 3)
Early OREL (Cal/
EPA); DMA not
currently (2005)
listed as CREL
OREL (Cal/EPA)
RFC, 0.01 mg/m3
(EPA/IRIS)
est. RFC, route-
extrapolated from est.
RfD (NAS-NRC)
CREL (Cal/EPA)
RFC, 0.01 mg/m3
(EPA/IRIS)
Citation/Link for Risk-Based \alue
IRIS entry (1 1/01/1989) indicates "no data" for RFC estimation; IRIS
considers RFC "not available." EPA 2006f and EPA 2006g (lowest
observed adverse effect level [LOAELJ-margin of exposure [MOE]
for long-term inhalation; note that the dose for the intermediate
inhalation duration is 0.04 mg/kg-d), http://www.epa.gov/oppsrrdl /
REDs/dicrotophos ired pdf, the LOAEL-MOE for 70-kg adult, 20
m3/d gives 0.2ug/m3
RfC withdrawn 01/01/1999 and is not available; early CREL,
Cal/EPA (2000), http://www.oehha.ca.gov/risk/pdf/APENDX-B.pdf
Cal/EPA 2005a (current list; this CREL established in 2000),
http://www.oehha.ca.gov/air/chronic rels/pdf/67561 .pdf

RfC, 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/irish/subst/0697.htm; CREL is 7 microgram/m3 from Cal/EPA
2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
NAS 2000a (provisional RfC from estimated RfD of 0.12 mg/kg-d),
http://books.nap.edu/catalo2.phpPrecord id= 9841, reflects
conservative assumptions until more data are available
Cal/EPA 2005a (current list; this CREL established in 2000),
http://www.oehha.ca.gov/air/chronic rels/pdf/67561 .pdf

RfC, 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
2ov/irish/subst/0697.htm; CREL is 7 micro2ram/m3 from Cal/EPA
2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
No specific air benchmark found for general public. Toxicity estimates for ED are available for military populations
(ECSOfor odor threshold ofl mglnf for 1 min exposure duration; incapacitating effects can occur at 5 mglnf for
1 min; Table 11-41, p. 11-60) in the following report: Army, Marine Corps, Navy, Air Force (2005). Potential
Military Chemical/Biological Agents and Compounds. FM 3-11.9. Commandant, US Army Chemical School, Ft.
Leonard Wood, MO. (Approved for public release, distribution is unlimited); this entry is included to introduce fate
products for which benchmarks exist
20
0.0002
RFC, 0.02 mg/m3
(EPA IRIS)
Estimated air
concentration
resulting in 1 x 1 0'6
risk; IUR at 0.0043
per ug/m3, (EPA,
IRIS)
EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value is lower, CREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.2ov/air/chronic rels/pdf/arsenics.pdf

No RfC established by EPA; EPA (1998), http://www.epa.gov/iris/
subst/0278.htm; CREL 0.03 u2/m3 (listed in 2001, study in 2000),
Cal/EPA 2005b,
http://www.oehha.ca.2ov/air/chronic rels/pdf/arsenics.pdf

Fate Notes
Hydroxyl radical oxidation half-life
is estimated at 7.3 hr
Hydrolysis product in moist air;
the hydroxyl radical half-life is 6 hr,
faster in polluted air
Hydrolysis product, can form in
moist air; hydroxyl radical half-life
is 3-30 d
Can form in moist air; can persist
as terminal fate product
Can hydrolyze to phosphorous
acid and methanol in moist air;
hydrolysis half-life is 10-19 d
Hydrolysis product, can form in
moist air; hydroxyl radical half-life
is 3-30 d
Can form in moist air; can persist
as terminal fate product
Can hydrolyze in moist air to
ethylarsenous oxide and HCI
Primary hydrolysis product in
moist air; subject to wet/dry
deposition
Terminal product, atmospheric
lifetime could be 5 to 1 5 d with
loss due to deposition

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Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Fenamiphos
Fenamiphos sulfoxide

Fenamiphos sulfone

Phosphoric Acid

Lewisite (Lewisite-1, agent L-l)

2-Chlorovinylarsonous acid (CVAA)
Lewisite oxide
CASRN
22224-92-6
31972-43-7

31972-44-8

7664-38-2

541-25-3

85090-33-1
3088-37-7
Air Concn
(•pglrr?)
(1.4)
(1.4)

(1.4)

10

3

(0.11)
(0.11)
Basis
NOAEL of 0.061
mg/kg-d and
MOE of 150 (turf
applicators) (EPA
OPPTS)
Conservatively
represented by
derivation from
NOAEL and
MOE for parent
indicator compound
Fenamiphos (EPA
OPPTS)
Conservatively
represented by
derivation from
NOAEL and MOE
for parent indicator
fenamiphos (EPA
OPPTS)
RfC, 0.01 mg/m3
(EPA/IRIS)

GPL of 0.003 mg/m3
for 7/24 exposure
over years from
assumed continuous
source GPL (CDC)

Estimated inhalation
RfC derived from
estimated RfD for
L-l
Estimated inhalation
RfC derived from
estimated RfD for
L-l
Citation/Link for Risk-Based \alue
EPA/IRIS considers that there are no data to support an RfC; EPA
2002b (highest MOE for turf, common application type; note
inhalation LOAEL is 0.85 mg/kg-d and inhalation NOAEL is 0.061
mg/kg-d), http://www.epa.gov/oppsrrdl /REDs/fenamiphos ired.
pdf identifies this inhalation NOAEL and MOE for short term and
intermediate inhalation, translates to 1 .4 ug/m3 for a 70-kg adult
inhaling 20 m3/d
EPA 2002b (as above; sulfoxide is considered less toxic), http://www.
epa.gov/oppsrrdl/REDs/fenamiphos ired.pdf inhalation NOAEL
and MOE for intermediate inhalation for parent suggest > 1 .4 ug/m3
for this form, for a 70-kg adult, 20 m3/d
EPA 2002b (as above; sulfone is considered less toxic),
http://www.epa.gov/oppsrrdl /REDs/fenamiphos ired.pdf inhalation
NOAEL and MOE for intermediate inhalation for parent suggest >
1 .4 ug/m3 for this form, for a 70-kg adult, 20 m3/d
RfC, 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/irish/subst/0697.htm; CREL is 7 microgram/m3 from Cal/EPA
2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
CDC 1988 (Final "Recommendations for Protecting the Health and
Safety against Potential Adverse Effects of Long- Term Exposure to Low
Doses of Agents GA, GB, VX, Mustard Agent [H, HD, T] and Lewisite
[L]),
http://wonder.cdc.gov/wonder/PrevGuid/p0000027/p0000027.asp

Estimated RfC for CVAA developed from estimated RfD for Lewisite
(finalized in Opresko et. al. 2001); see USACHPPM (1999) for
calculation of est. RfC for CVAA
Estimated RfC for Lewisite oxide developed from estimated RfD
for Lewisite (finalized in Opresko et. al. 2001); see USACHPPM
(1 999) for calculation of est. RfC for Lewsite oxide and Watson and
Dolislager (2007) for recent documentation.
Fate Notes
Hydroxyl radical oxidation half-life
is 2 to 5 hr; forms the sulfoxide
and sulfone
Primary oxidation product; subject
to wet/dry deposition

Forms from oxidation of the
sulfoxide; subject to wet/dry
deposition
Can form in moist air; can persist
as terminal fate product

Can persist 1—3 d; in moist air, can
hydrolyze rapidly (<2 min half-life)
to CVAA (2-chlorovinylarsonous
acid) and HC1; hydroxyl radical
oxidation half-life about 1.2 d;
ultraviolet absorption spectrum
of 200— 350 nm indicates some
photodegradation may occur
Primary hydrolysis product, can
rapidly form in moist air within
minutes; subject to wet/dry
deposition
Dehydration product of
2-chlorovinylarsonous acid; subject
to wet/dry deposition

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Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Hydrogen chloride (HCl)

Arsenic, inorganic




Lewisite (Lewisite-2, agent L-2)
Hydrogen chloride (HCl)

Arsenic, inorganic


Lewisite (Lewisite-3, agent L-3)
Methyl parathion

p-Nitrophenol


CASRN
7647-01-0

7440-38-2




40334-69-8
7647-01-0

7440-38-2


40334-70-1
298-00-0

100-02-7


Air Concn.
(mlnf)
20

0.0002




(3)
20

0.0002


(3)
0.01

0.1


Basis
RFC, 0.02 mg/m3
(EPA IRIS)

Estimated air
concentration
resulting in 1 x 10~6
risk; IUR at 0.0043
per ug/m3, (EPA
IRIS)
Conservatively
represented by GPL
for L-l CDC 1988
RFC, 0.02 mg/m3
(EPA IRIS)

Estimated air
concentration
resulting in 1 x 1 0'6
risk; IUR at 0.0043
per ug/m3, (EPA
IRIS)
Conservatively
represented by GPL
for L-l (CDC, 1988)
RFC, 0.01 to 0.08 ug/
m3 for seasonal and
chronic exposures
as calculated by CA
Dept. of Pesticide
Regulation in 1999
(Cal/EPA)
Proposed Rhode
Island (2004) and
NY acceptable
ambient level (AAL),
annual limit (New
York Statement
Department of
Environmental
Conservation
[NYSDEC] and State
of Rhode Island)
Citation/Link for Risk-Based \alue
EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value is lower, CREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/ pdf77647010.pdf

No RfC established by EPA; EPA (1998), http://www.epa.gov/iris/
subst/0278.htm; CREL is 0.03 ug/m3 (listed in 2001, study in 2000),
Cal/EPA 2005a, http://www.oehha.ca.gov/air/chronic rels/pdf/
arsenics.pdf

CDC 1988 (as for L-l) (separate value not established for L-2 but is
considered much less toxic than L-l
EPA (1995), http://www.epa.gov/iris/subst/0396.htm:
non-EPA value is lower, CREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/ pdf77647010.pdf

No RfC established by EPA; EPA (1998), http://www.epa.gov/iris/
subst/0278.htm; CREL 0.03 ug/m3 (listed in 2001, study in 2000),
Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/pdf/arsenics.pdf

CDC 1988 (as for L-l) (separate values not established for L-3 but is
much less toxic than L-l
EPA/IRIS considers there to be no data to support a RfC; Cal/EPA
1999 (Scientific Review Panel Methyl Parathion),
http://www.arb.ca.gov/srp/srp3.pdf ("the RfCs of methyl parathion
calculated in the report. ..ranges from 0.01 -0.08 microgram/m3...for
seasonal and chronic exposures"); the lowest value of 0.01 microgram/
m3 is considered protective
Proposed state acceptable ambient level, AAL, for New York State and
Rhode Island (2004), http://www.dem.ri.gov/programs/benviron/
air/pdf/airtoxgl.pdf. The Rhode Island MO (minimal quantity) of 1 1
is in units of pounds/year (Ibs/yr) and refers to the allowable facility
emissions, not ambient air concentrations. For documentation, please
see Rhode Island Air Toxics Guideline (2004) cited for 4-nitrophenol.
Fate Notes
Hydrolysis product, is incorporated
into moisture in air; subject to wet/
dry deposition

Terminal product, atmospheric
lifetime could be 5 to 1 5 d with
loss due to deposition


Can hydrolyze in moist air to
bis(2-chlorovinyl)arsenious acid
and HCl
Hydrolysis product, is incorporated
into moisture in air, subject to wet/
dry deposition

Terminal product, atmospheric
lifetime could be 5 to 1 5 d with
loss due to deposition

Resists hydrolysis; subject to wet/
dry deposition
Hydroxyl radical half-life is 6.5
hr to 3.6 d; could hydrolyze in
moist air to p-nitrophenol and
dimethylphosphorothioic acid with
a half-life of 4-89 d
Can form in moist air; hydroxyl
radical half-life is 4 d; photolysis
half-life can range from hr to
>1 week (wk)

-------
Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Methyl paraoxon

Methanol

Phosphoric acid

Mustard, sulfur (agent H) and distilled
sulfur mustard (agent HD)



Mustard sulf oxide


Mustard sulfone


Mustard, sulfur, distilled, with T
(agent HT: mixture of 60% HD, 40% T)
Mustard sulfoxide


CASRN
950-35-6

67-56-1

7664-38-2

505-60-2



5819-08-9


471-03-4


Agent T =
CAS 6392-
89-8; Agent
HD = CAS
505-60-2
5819-08-9


Air Concn.
(jtgln?)
(0.01)

4,000

10

0.02



(0.02)


(0.02)


0.02
(0.02)


Basis
Equivalent to
calculated RfC
for parent methyl
parathion, 0.01
microgram/m3,
as per Cal/EPA
guidance
(Cal/EPA)
CREL
(Cal/EPA)

RfC, 0.01 mg/m3
(EPA/IRIS)

GPL
(CDC, ATSDR)



Protectively
represented by the
H/HD value above
(CDC, ATSDR)
Protectively
represented by the
H/HD value above
(CDC, ATSDR)
GPL
(CDC, ATSDR)
Protectively
represented by the
H/HD value above
(CDC, ATSDR)
Citation/Link for Risk-Based \folue
Cal/EPA 1999 (Scientific Review Panel Methyl Parathion),
http://www.arb.ca.gov/srp/srp3.pdf; considered methvl paraoxon
potentially 1 0 times more toxic than parent by inhalation;
nevertheless, Cal/EPA determined that "the calculation of reference
concentration [for methyl parathion] takes into account the
concomitant presence of methyl paraoxon at approximately 25%
of the level of methyl parathion" (pp. 7-8, item 31 of Cal/EPA
1999).
Cal/EPA 2005a (current list; this CREL established in 2000),
http://www.oehha.ca.gov/air/chronic rels/pdf/67561 .pdf

RfC, 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/irish/subst/0697.htm; CREL is 7 microgram/m3 from Cal/
EPA 2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
CDC 2004 (Interim Recommendations for Airborne Exposure Limits
for Chemical Warfare Agents Hand HD [Sulfur Mustard]),
http://www.cdc.gov/nceh/demil/files/Federal%20Register%20Mu
stard%20AEL%205 2004.pdf; this is also the intermediate MRL
for sulfur mustard from 2003, in ATSDR 2005, http://www.atsdr.
cdc.gov/mrls/index.htm

CDC 2004 (as above for H),
http://www.cdc.gov/nceh/demil/files/Federal%20Register%20
Mustard%20AEL%205 2004.pdf; and int. MRL for H from
2003, in ATSDR 2005, http://www.atsdr.cdc.gov/mrls/index.html
CDC 2004 (as above for H),
http://www.cdc.gov/nceh/demil/files/Federal%20Register%20Mus
tard%20AEL%205 2004.pdf; and int. MRL for H from 2003, in
ATSDR 2005, http://www.atsdr.cdc.gov/mrls/index.htm
ATSDR 2005 and CDC 2004, as above for agents H and HD; T
note CDC (2004) points out that "... toxicity data for agent T are
inadequate for setting exposure limits . . . very low vapor pressure
for agent T. . . precludes it as a vapor hazard under normal ambient
conditions. For sulfur mustard and T mixtures, air monitoring for
sulfur mustard alone should be sufficient under most circumstances
to prevent airborne exposure to it."
CDC 2004 (as above for HD),
http://www.cdc.gov/nceh/demil/files/Federal%20Register%20
Mustard%20AEL%205 2004.pdf; and int. MRL from 2003, in
ATSDR 2005, http://www.atsdr.cdc.gov/mrls/index.htm
Fate Notes
Produced by oxygen radical oxidation;
can hydrolyze to para-nitrophenol (above)
and dimethylphosphoric acid, and the two
compounds below
Hydrolysis product, can form in moist
air; hydroxyl radical oxidation half-life is
3-30 d
Can form in moist air; can persist as
terminal fate product

As for HD (pure version of H, is the
distilled form), oxidizes to sulfoxide and
then (in more oxidizing conditions)
sulfone; estimated half-life for hydroxyl
radical oxidation is 1 .4 d, and atmospheric
half-life is 2.1 d

Can persist in soil for months; subject to
wet/dry deposition


Can persist in soil for months; subject to
wet/dry deposition


More persistent than HD (>2 d); for the
HD fraction, see HD/H above
Can persist in soil for months; subject to
wet/dry deposition



-------
Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Mustard sulfone
Phorate
Hydrogen sulfide (H2S)
Hydrogen sulfate (H2SO4), or
sulfuric acid
Sulfate (SO2'4) (Cal/EPA CAS)
Formaldehyde
Carbon monoxide (CO)
Sarin (agent GB)
Hydrogen fluoride (HP)
CASRN
471-03-4
298-02-2
7783-06-4
7664-93-9
9-96-0
50-00-0
630-08-0
107-44-8
7664-39-3
Air Concn.
(figln?)
(0.02)
Basis
Protectively
represented by the
H/HD value above
(CDC, ATSDR)
Citation/Link for Risk-Based \alue
CDC 2004 (as above for HD),
http://www.cdc.gov/nceh/demil/files/Federal%20Redster%20Must
ard%20AEL%205 2004.pdf; and int. MRL from 2003, in ATSDR
2005, http://www.atsdr.cdc.gov/mrls/index.htm
No specific air benchmark found; this entry is included to introduce a fate product for which a benchmark
exists (note that for inhalation exposures, the EPA 2006 OPP Interim reregistration eligibility decision (IRED)
for Phorate considereda chronic oralNOAEL of 0.05 mg/kg-d, assumed full absorption; could suggest upper
boundtarget of 1.75 figlm1 with 100 for interspecies-intraspecies factors alane.)1his estimate is consistent with
the recommended chronic RfD of 0.0005 mgphoratelkg-d presented in Table 2, p. 10 of the OPP final Interim
Reregistration Eligibility Decision (see www. epa.govloppsrrdllreregistrationlREDslphorate ired.pdf)
2
1
25
0.08
10,000
0.001
14
RFC, 2 ug/m3
(EPA IRIS)
CREL
(Cal/EPA)
CREL
(Cal/EPA)
IUR, 0.000013 per
ug/m3 at 10'6 risk, for
a risk-specific level of
0.08 ug/m3
(EPA IRIS)
NAAQS for CO
(EPA OAQPS)
GPL
(CDC)
CREL,
(Cal/EPA)
EPA (2003), http://www.epa.gov/iris/subst/0061.htm; the CREL is
10 ug/m3, Cal/EPA 2005b (listed in 2000),
http://www.arb.ca.gov/toxics/healthval/contable.pdf;
note the draft intermediate MRL is 28 ug/m3 (see www.atsdr.cdc.
gov/mrls/index.html)

Cal/EPA 2005b (this CREL was listed in 2001),
http://www.arb.ca.gov/toxics/healthval/contable.pdf

Cal/EPA 2005b (this CREL was listed in 1992),
http://www.arb.ca.gov/toxics/healthval/contable.pdf

EPA (1991a), http://www.epa.gov/iris/subst/04l9.htm. for 10'6risk
level; chronic MRL of 0.008 ppm is 9.8 ug/m3 (from 1999), and the
CREL is 3 ug/m3 (from 2005), in Cal/EPA 2005a,
httD://www.oehha.ca.gov/air/chronic rels/Ddf/50000.Ddf

EPA 1 997b, http://www.epa.gov/air/criteria.html: note that this
standard (from 1990) is an 8-hr average annual ceiling value
CDC 2003 (Final Recommendations for Protecting Human Health
from Potential Adverse Effects of Exposure to Agents GA (Tabun),
GB (Sarin), and VX) http://a257.g.akamaitech.net/7/257/2422/
I4mar20010800/edocket.access.gpo.gov/2003/03-25583.htm

Cal/EPA 2003 (Adoption of Chronic Reference Exposure Levels for
Fluorides including Hydrogen Fluoride),
http://www.oehha.ca.gov/air/chronic rels/HvFluoCREL.html note
that the value for F (vs. HF) is 13 ug/m3 (also note that the ATSDR
acute MRL is 0.02 ppm or 16 ug/m3
Fate Notes
Can persist in soil for months;
subject to wet/dry deposition
Half-life for hydroxyl radical
oxidation is <1.5 hr, 30 min
for photolysis; in moist air, can
hydrolyze with a 30- to 60-d half-
life to the chemicals below
Hydrolysis product in moist air;
oxidizes to hydrogen sulfate
Oxidation product in moist air;
dissociates to sulfate
Terminal product can persist in air,
is subject to deposition
Hydrolysis product in moist air;
photolysis half-life is 4—6 hr; can
react with radicals to produce
formic acid and carbon monoxide
Can persist for several weeks; can
oxidize to CO
Photodegradation does not appear
significant; hydroxyl radical half-life
is 1 0 hr; half-life for hydrolysis in
moist air is 3 d, forming HF and
IMPA
Primary GB hydrolysis product in
moist air, with IMPA, which only
very slowly hydrolyzes to MPA and
isopropanol; subject to wet/dry
deposition

-------
Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Methylphosphonic acid (MPA)


Isopropanol (isopropyl alcohol)

Soman (agent GD)
Hydrogen fluoride (HP)

Methylphosphonic acid (MPA)

Tabun (agent GA)


Dimethylamine

Hydrogen cyanide (HCN)
Cyanide (CN~),jree
Phosphoric acid


CASRN
993-13-5


67-63-0

96-64-0
7664-39-3

993-13-5

77-81-6


124-40-3

74-90-8
57-12-5
7664-38-2


Air Concn
(pg/m3)
24


7,000

0.001
14

24

0.001


2

3
9
10


Basis
Estimated RFC
(Munro/CHPPM);
re-confirmed by
Talmage et. al.
(2007)
OREL
(Cal/EPA)

GPL
(Army Office of the
Assistant Secretary)
OREL, 14 ug/m3
(Cal/EPA)

Estimated RFC
(Munro/CHPPM);
reconfirmed by
Talmage et al (2007)
GPL
(CDC)


Early CREL (Cal/
EPA); DMA not
currently (2005)
listed as CREL
RFC
(EPA IRIS)
CREL
(Cal/EPA)
RFC, 0.01 mg/m3
(EPA/IRIS)

Citation/Link for Risk-Based Value
Munroetal. 1999,
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; and Talmage et al (2007)

Cal/EPA 2005b (level established in 2000),
http://www.arb.ca.gov/toxics/healthval/contable.pdf

DA (2004) . "Interim Guidance Policy for New Airborne Exposures
Limits for GB, GA, GD, GF, VX, H, HD and HT" Department
of the Army, Office of the Assistant Secretary (Installations and
Environment) .110 Army Pentagon, Washington, DC (1 8 Jun
2004).
Cal/EPA 2003 (as listed under sarin, above),
http://www.oehha.ca.gov/air/chronic rels/HvFluoCREL.html (for
further context, see entry for HF under sarin above)
Munro et al. 1999, http://ehp.niehs.nih.gov/members/1999/
107p933-974munro/munrotabl6B.GIF; and Talmage et al (2007)

CDC 2003 (Final Recommendations for Protecting Human
Health from Potential Adverse Effects of Exposure to Agents GA
(Tabun), GB (Sarin), and VX) as for agent GB, sarin above), at
http://a257.g.akamaitech.net/7/257/2422/ 1 4mar200 1 0800/
edocket.access.gpo.gov/2003/03-25583.htm

Early CREL, Cal/EPA (2000), http://www.oehha.ca.gov/risk/pdf/
APENDX-B.pdf

EPA (1994), http://www.epa.gov/iris/subst/0060.htm: based on
cyanide toxicity (see Table 6 entry for further fate products)
Cal/EPA 2005b for inorganic cyanide compounds (reviewed in
2000), http://www.arb.ca.gov/toxics/healthval/contable.pdf
RfC, 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/irish/subst/0697.htm; CREL is 7 microgram/m3 from Cal/
EPA 2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
Fate Notes
Forms very slowly from IMPA in
moist air (estimated 1,900 yr half-
life); is chemically stable

Residence time in air is 1—2 d;
hydroxyl radical oxidation forms
acetone, acetaldehyde
Hydroxyl radical half-life is 8 hr;
can hydrolyze in moist (alkaline) air,
within min-hr to pinacolyl MPA and
HF
Primary hydrolysis product of GD,
can form in moist air; subject to wet/
dry deposition
Forms very slowly in moist air
(estimated 1,900 yr half-life); is itself
chemically stable
Hydroxyl radical half-life is 5 hr; can
hydrolyze in moist air to compounds
below, with a half-life of 8 hr at 20°C
and pH 7.4, 14-28 hr at pH 7, 25°C


Hydrolysis product in moist air, as
is ethylphosphoryl cyanidate, which
forms HCN; the hydroxyl radical
half-life is 6 hr, faster in polluted air
From hydrolysis in moist air; subject
to wet/dry deposition; hydroxyl
radical half-life 1—3 yr
Dissociation product, coexists with
most as HCN in moist air
Can form in moist air, can persist as
terminal product


-------
Table 5  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Air
Chemical
Trimethyl phosphite (TMP)
Dimethyl phosphite (DMP orDMHP)
Methanol
Phosphoric acid
VX,or:
O-ethyl-5-[2-(diisopropylamino)ethyl]
methylphosphonothioate
S-[2-(diisopropylamino)ethyl]
methylphosphonothioic acid
(EA 2192)
Diisopropyl ethyl mercilptoilmine
(DESH)
O-ethyl methylphosphonic acid
(EMPA)
Methylphosphonic add (MPA)
2-Diisopropylaminoethanol
O-ethylmethylphosphonothioic
acid(EMPTA)
CASRN
121-45-9
868-85-9
67-56-1
7664-38-2
50782-69-9
73207-98-4
5842-07-9
1832-53-7
993-13-5
96-80-0
18005-40-8
Air Concn.
(mlrrf)
Basis
Citation/Link for Risk-Based Value
No specific air benchmark found;
this entry is included to introduce the fate product for which a benchmark exists
420
4,000
10
0.0006
0.0007
4.6
34
24
10
8.5
est. RFC, route-
extrapolated from
est. RfD (NAS-
NRC)
OREL
(Cal/EPA)
RFC, 0.01 mg/m3
(EPA/IRIS)
GPL
(CDC)
Estimated RFC
(Munro, Talmage/
CHPPM)
Estimated RFC
(Munro, Talmage/
CHPPM)
Estimated RFC
(Talmage/CHPPM)
Estimated RFC
(Munro, Talmage/
CHPPM)
Estimated RFC
(Munro, Talmage/
CHPPM)
Estimated RFC
(Munro, Talmage/
CHPPM)
NAS 2000a (provisional RFC From estimated RFD oF0.12 mg/kg-
d), http://books.nap.edu/catalog.phpPrecord id= 9841, reflects
conservative assumptions until more data are available
Cal/EPA 2005a (current list; this CREL established in 2000),
http://www.oehha.ca.aov/air/chronic rels/pdF/67561 .pdF
RFC, 0.01 me/m3 From EPA/IRIS, EPA (1995), http://www.epa.
gov/irish/subst/0697.htm; CREL is 7 microgram/m3 From Cal/
EPA 2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdF
CDC 2003 (Final Recommendations For Protecting Human
Health From Potential Adverse Effects oF Exposure to Agents
GA (Tabun), GB (Sarin), and VX) as For agent GB, sarin above,
athttp://a257.g.akamaitech.net/7/257/2422/l4mar20010800/
edocket.access.gpo.gov/2003/03-25583.htm

Munro et al. 1999 (solid compound and non- volatile),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; and Talmage et al (2007)

Munro et al. 1999, http://ehp.niehs.nih.gov/members/1999/
107p933-974munro/ munrotabl6B.GIF; and Talmage et al.
(2007)
Munro et al. 1999, http://ehp.niehs.nih.gov/members/1999/
107p933-974munro/ munrotabl6B.GIF; and Talmage et al.
(2007)
Munro etal. 1999,
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; and Talmage et al. (2007)
Munro et al. 1999, http://ehp.niehs.nih.gov/members/1999/
107p933-974munro/ munrotabl6B.GIF; and Talmage et al.
(2007)
Munro et al. 1999, http://ehp.niehs.nih.gov/members/1999/
107p933-974munro/ munrotabl6B.GIF; and Talmage et al.
(2007)
Fate Notes
Can Form methanol and DMP
in moist air, hydrolysis limited by
solubility, halF-liFe is 4-10 d
Can hydrolyze to phosphorous acid
and methanol in moist air; hydrolysis
halF-liFeislO-19d
Hydrolysis product can Form in moist
air; hydroxyl radical halF-liFe is 3—30 d
Can Form in moist air; can persist as
terminal Fate product
Moderately persistent at 2 d to 1 wk;
57-hr halF-liFe at neutral pH; in moist
air can Form EA 2192 and ethanol (ph
>7) or DESH and EMPA (pH <6);
3-hr hydroxyl radical halF-liFe
Primary hydrolysis product; From
distilled water tests (per moist air),
-halF Follows this pathway; resists
hydrolysis
Primary hydrolysis product; in
distilled water tests, about a third
Follows this pathway; is more
persistent than VX
Primary hydrolysis product; in
distilled water tests, about a third
Follows this pathway; hydrolyzes very
slowly to MPA and ethanol
Hydrolysis product oFEMPA, MPA
itselFis chemically stable
Primary hydrolysis product oF VX,
persistence expected to be similar to
DESH
Primary hydrolysis product oF VX, can
oxidize to EMPA

-------
              a Table 5 identifies risk-based criteria that address priority chemicals and key transformation products for which benchmarks were found; 3 of these threat chemicals are represented by their fate products -
          ethyldichloroarsine (ED), phorate, and trimethyl phosphite (TMP) — and no relevant benchmarks were found for tetraethyl pyrophosphate, (TEPP). Fate products are indented in italics, and only those with relevant
          benchmarks are shown. Some products common to more than one primary contaminant, while others are unique. For VX, associated impurities not in the NHSRC list or SAM report are not  included; for those other
          chemicals, see Munro et al. (1999) and Talmage et al. (2007).
              Except as indicated, these concentrations represent long-term (repeated or continuous) exposures. Parentheses identify derived concentrations, e.g., from values for related chemicals. Calculated values are rounded to two
          significant figures. MOE = margin of exposure. Under standard conditions, mg/n£ = (molecular weight/24.5) x ppm.
              EPA benchmarks are prioritized, with others included as further context; lower values shown in lighter font (green). The IRIS database was initially accessed in 2005 and checked again in September 2007 as this document
          was completed. Italicized dates shown in parentheses here and in subsequent tables represent when the benchmarks were established (or in some  cases further reviewed), so that time frame can be appreciated when comparing
          with other benchmarks established earlier or later.  For example, while the current set of CRELs is dated 2005, the years in which individual limits were formalized are also shown in these tables. Similarly, from the December
          2006 MRL list, the dates individual limits were established rather than that most recent overall publication date are presented in these tables.
              No direct chronic public benchmarks were found for the following chemicals in this review:  dicrotophos, ED, fenamiphos, mevinphos, nicotine, phorate, strychnine, TEPP, and TMP. Parentheses are used to distinguish
          preliminary indicators derived for dicrotophos and fenamiphos from information developed for long-term inhalation by the EPA Office of Prevention, Pesticides, and Toxic Substanes (OPPTS), notably the Office of Pesticide
          Programs (OPP), which suggests method validation targets could be further below those levels. Similarly, italicized values in parentheses for several fate products represent generally conservative preliminary indicators, as they
          reflect benchmarks for parent compounds that are considered more toxic.
              To further address gaps, acute exposure levels and data for similar chemicals were also checked for insights into possible bounding context and relative toxicity. As a note for ED, a 1 hr AEGL 2 of 29 ug/m3 is an interim
          inhalation value above (see EPA website http://www.epa.gov/oppt/aegl/pubs/restl36.html); thus it would be considered a very high bound, e.g.,  method validation to support final decontamination levels for chronic exposures
          would be expected to target a much lower concentration.
              Chemical Abstracts Service Registry Number [American Chemical Society] (CAS/RN)
IN)

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IN)
IN)
Table 6  Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Air
Chemical
Arsine (agent SA)

Arsenic, inorganic


Cyanogen chloride (agent CK)

Hydrogen chloride (HCl)
Ammonia (NH})

Cyclohexyl sarin (agent GF, or
cyclosarin)
Hydrogen fluoride (HP)

CASRN
7784-42-1

7440-38-2


506-77-4

7647-01-0
7664-41-7

329-99-7
7664-39-3

Air Concn.
(ftglrr?)
0.05

0.0002


9.0

20
100

0.001
14

Basis
RFC
(EPA IRIS)

Estimated air
concentration
resulting in 1 x 10~6
risk; IUR at 0.0043
per ug/m3, (EPA
IRIS)
CREL for inorganic
cyanide compounds,
9.0 ug/m3 (Cal/
EPA)
RFC, 0.02mg/m3
(EPA IRIS)
RFC, 0.1 mg/m3
(EPA IRIS)

GPL
(Army Office of the
Assistant Secretary)
CREL
(Cal/EPA)

Citation/Link for Risk-Based \alue
EPA (1994), http://www.epa.gov/iris/subst/0672.htm:
this is also the CREL (from 1996) in Cal/EPA 2005b,
http://www.arb.ca.gov/toxics/healthval/contable.pdf

No RfC for inorganic arsenic established by EPA; EPA (1998),
http://www.epa.gov/iris/subst/0278.htm
CREL is 0.03 ug/m3 (listed in 2001), evaluated in Cal/EPA
(2005b),
http://www.oehha.ca.gov/air/chronic rels/pdf/arsenics.pdf

The CREL for inorganic cyanide compounds is 9.0 ug/m3 (listedin
2000), in Cal/EPA 2005b,
http://www.oehha.ca.gov/air/chronic rels/pdf/7782505.pdf

EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value is lower, CREL 9 ug/m3 (2000) in Cal/EPA 2005b,
http://www.oehha.ca.2ov/air/chronic rels/pdf/7647010.pdf
EPA (199 la), http://www.epa.gov/iris/subst/0422.htm: a non-EPA
value is lower, the MRL of 0.1 ppm or 70 ug/m3, ATSDR 2005,
http://www.atsdr.cdc.2ov/mrls.html; ammonia CREL 200 u2/m3,
anhydrous-aqueous (listed 2000), Cal/EPA 2005b,
http://www.oehha.ca.gov/air/chronic rels/pdf/76644 1 7.pdf
DA (2004). "Implementation Guidance Policy for New
Airborne Exposures Limits for GB, GA, GD, GF, VX, H, HD
and HT." Department of the Army, Office of the Assistant
Secretary (Installations and Environment). 1 10 Army Pentagon,
Washington, D.C. (18 Jun 2004)
Cal/EPA 2003 (Adoption of Chronic Reference Exposure Levels for
Fluorides Including Hydrogen Fluoride),
http://www.oehha.ca.gov/air/chronic rels/HvFluoCREL.html note
that the value for F (versus HF) is 13 ug/m3 (also note that the
ATSDR acute MRL is 0.02 ppm or 16 ug/m3)
Fate Notes
Does not persist beyond min-hr;
decomposes in moist air and light to
deposit elemental arsenic; can explode
on contact with warm, dry air; can
hydrolyze to arsenic acids, hydrides;
can oxidize to trivalent, pentavalent
arsenic compounds that settle out
(deposit on surfaces)
Oxidation product; atmospheric
lifetime could be 5 to 1 5 d with loss
due to deposition

Persists only 1—10 min in air; reacts
with hydroxyl radicals to liberate
hydrogen; can hydrolyze in moist air to
form cyanic acid, HCl (half-life is
1 minat45°C, 10hrat5°C)
Hydrolysis product, would be
incorporated into moisture in air;
subject to wet/dry deposition
Formed from the cyanic acid (HOCN)
hydrolysis product, along with CO ;
the vapor can persist for about 1 wk

Hydroxyl radical reaction half-life is
2 d; this is also the hydrolysis half-life
in moist air at 25°C
Primary hydrolysis product of GF, can
form in moist air along with cyclohexyl
MPA; subject to wet/dry deposition


-------
     Table 6 Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Air
Chemical
Methylphosphonic add (MPA)
Ethyl sarin (agent GE)
Hydrogen cyanide
(HCN, agent AC)
Cyanide (CN), free
Nitrogen dioxide (NO2)

Nitric add (UNO 3)
Carbon monoxide (CO)
Mustard, nitrogen (HN-2)
Hydrogen chloride (HCl)
CASRN
993-13-5
1189-87-3
74-90-8
57-12-5
10102-44-0
7697-37-2
630-08-0
51-75-2
7647-01-0
Air Concn
(ftg/m3)
24
NA
3
9
100
(86); (acute
only)
10,000
Basis
Estimated RFC
(Munro/CHPPM);
re-confirmed by
Talmage et al (2007)
No specific values
found for GE.
RfC
(EPA IRIS)
OREL
(Cal/EPA)
NAAQSforNO2
(EPA OAQPS)
AREL
(Cal/EPA)
NAAQS for CO
(EPA OAQPS)
Citation/Link for Risk-Based Value
Munro et al. 1999, http://ehp.niehs.nih.gov/
members/1999/107p933-974munro/munrotabl6B.GIF;and
Talmage et al (2007)
No specific values found for GE. In the absence of any available
literature from which to draw a relative potency comparison
with any other nerve agent, it is recommended that no risk-based
criteria be provided at this time. If data or analyses can be made
available, this compound can be re-visited.
EPA 1994, http://www.epa.gov/iris/subst/0060.htm: based on
cyanide toxicity
Cal/EPA 2005b, for inorganic cyanide compounds (reviewed in
2000) http://www.arb.ca.gov/toxics/healthval/contable.pdf
EPA 1 997b, http://www.epa.gov/air/criteria.html; note that the air
quality standard (from 1990) is the annual arithmetic mean;
CREL is 470 ug/m3 (from 1992), in Cal/EPA 2005b,
http://www.arb.ca.gov/toxics/healthval/contable.pdf

Cal/EPA (2000), only for acute, no chronic level found,
http://www.oehha.org/air/acute rels/allAcRELs.html
EPA 1 997b, http://www.epa.gov/air/criteria.html: note that this
standard (from 1990) is an 8-hr average annual ceiling value
No specific air benchmark found;
this entry is included to introduce the fate product for which a benchmark exists
20
RfC, 0.02 mg/m3
(EPA IRIS)
EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value is lower, CREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/pdf/7647010.pdf
Fate Notes
Hydrolysis product, forms very slowly
from cyclohexyl methyl-phosphonic
acid; MPA is stable
Not available. In the absence of
compound-specific fate data for agent
GE or documented comparison
with agent GB degradation, it is
recommended that no fate reactions
be presented at this time. When data
or analyses become available, this
compound can be re-visited.
Can disperse rapidly; resists
degradation, with atmospheric
residence time of 1—3 yr depending on
hydroxyl radical concentration
Dissociation product, coexists with
most as HCN in moist air
Hydroxyl radical oxidation of HCN
forms nitric oxide (NO), which rapidly
interconverts with NO2 in sunlight;
can form nitrous and nitric acids in
moist air
Product of NO2 reaction in moist air;
subject to wet/dry deposition
Can oxidize to CO ; can persist for
several weeks
Hydroxyl radical reaction half-life 5 hr
to 2 d; dimerizes; hydrolyzes to HCl
and N methyldiethanolamine with a
half-life of llhr
Hydrolysis product, is incorporated
into moisture in air; subject to wet/dry
deposition
IN)
CO

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      Table 6 Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Air
IN)
Chemical
Perfluoroisobutylene (PFIB)
Hydrogen fluoride (HP)

Red phosphorus (RP)
Phosphine
Phosphoric add

Tear gas (agent CS)


Titanium tetrachloride (FM)
CASRN
382-21-8
7664-39-3

7723-14-0
7803-51-2
7664-38-2

2698-41-1


7550-45-0
Air Concn.
(•pgln?)
(0.3)
14

(10)
0.3
10

(0.03)


0.1
Basis
Estimated as
approximately
equivalent to
phosgene RFC of 0.3
ug/m3 (EPA IRIS)
OREL
(Cal/EPA)

Related RFC for
phosphoric acid,
1 0 ug/m3 (from
RP combustion
products)
(EPA IRIS); NRC
(1997)
RfC, 0.0003 mg/m3
(EPA IRIS)
RfC, 0.01 mg/m3
(EPA IRIS)

Protectively
represented by the
RfC, 0.00003 mg/
m3 for the tear gas
form CN
(EPA IRIS)
Chronic MRL,
0.0001 mg/m3
(ATSDR)
Citation/Link for Risk-Based Value
EPA (2006f), http://www.epa.gov/iris/subst/0487.htm: estimated
as approximately equivalent to phosgene RfC based on comparison
of Provisional Advisory Level (PAL) concentrations for PFIB and
phosgene under current review by NHSRC
Cal/EPA 2003 (Adoption of Chronic Reference Exposure Levekfor
Fluorides Including Hydrogen Fluoride), http://www.oehha.ca.gov/
air/chronic rels/HvFluoCREL.html
(for further context, see entry for HF under agent GE above)
EPA (1995tt), http://www.epa.gov/iris/subst/0697.htm: note
that this RfC for phosphoric acid is based on RP combustion
products (likely exposure condition and consistent with NRC
[1997] appraisal that phosphoric acid is key toxic component of
RP fume), which include phosphorous and phosphoric acids.
The CREL for phosphoric acid is 7 microgram/m3 (Cal/EPA
2005b)(listed in 2000). For comparison, the CREL for phosphoric
acid is 7.0 micrograms/m3 and that for the more toxic white P
(WP) is 0.07 ug/m3, Cal/EPA 2005b (listed in 1991),
http://www.arb.ca.gov/toxics/healthval/contable.pdf
EPA (1995a), http://www.epa.gov/iris/subst/0090.htm; the CREL
is 0.8 ug/m3 (listed in 2002), in Cal/EPA 2005a,
http://www.oehha.ca.gov/air/chronic rels/pdf/78035 1 2.pdf
RfC of 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/iris/subst/0697.htm; CREL is 7 microgram/m3 from Cal/EPA
2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
EPA (1991 A) (this RfC is for the tear gas form CN, or
2-chloroacetophenone, CAS number 532-27-4),
http://www.epa.gov/iris/subst/0537.htm; tear gas form CS is less
toxic than tear gas form CN, per Rega et al. 2006,
http://www.emedicine.com/emerg/topic9l4.htm, and others

ATSDR 1997d, http://www.atsdr.cdc.gov/toxprofiles/tpl01.html
Fate Notes
Thermal by-product of Teflon synthesis
(same precursors); in moist air, can
hydrolyze to fluorophosgene, forms
CO2 and HF
Secondary hydrolysis product, can
form in moist air; subject to wet/dry
deposition

Highly flammable solid, reacts slowly
with water vapor and oxygen to
produce phosphine in air (estimated
half-life >3,500 yr), accelerated by
metals and oxidizers
Hydrolysis product, can form in moist
air; hydroxyl radical half-life is about
Id
Can form in moist air; can persist as a
terminal fate product

Can hydrolyze in moist air in
minutes, to 2-chlorobenzaldehyde and
malononitrile (relatively toxic); note:
in the body (but not in air), converts to
cyanide and thiocyanate

Disperses readily; in moist air can
hydrolyze to produce smoke of
HC1 and titanium oxychloride and
hydroxide, with half-life of hours

-------
         Table 6  Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Air
Chemical
Hydrogen chloride (HCl)
VG, Amiton, or:
O,O-diethyl-S [2 (diethylamino)
ethyl] phosphorothioate
Phosphoric acid
VM, or:
O-ethyl-5-[2-(diethylamino)ethyl]
methylphosphonothioate
Vx, or:
O-ethyl-5-[2-(dimethylamino)ethyl]
methylphosphonothioate
CASRN
7647-01-0
78-53-5
7664-38-2
21770-86-5
20820-80-8
Air Concn.
(ftglrr?)
20
Basis
RFC, 0.02 mg/m3
(EPA IRIS)
Citation/Link for Risk-Based Value
EPA (1995a), http://www.epa.gov/iris/subst/0396.htm: non-EPA
value lower, OREL 9 ug/m3 (2000) in Cal/EPA 2005a,
http://www.oehha.ca.aov/air/chronic rels/pdf/7647010.pdf
No specific air benchmark was found; this entry is included to introduce a fate product for which a specific
benchmark exists
10
RFC, 0.01 mg/m3
(EPA IRIS)
RFC of 0.01 mg/m3 from EPA/IRIS, EPA (1995), http://www.epa.
gov/iris/subst/0697.htm; CREL is 7 microgram/m3 from Cal/EPA
2005b, http://www.arb.ca.gov/toxics/healthval/contable.pdf
No compound-specific information is available, so an assumption cannot be made about toxicity.
No specific benchamark found.
"No toxicity estimates are recommended at this time because
data are lacking"; Dept. of the Army (2005), Potential Military
Chemical/Biological Agents and Compounds. FM 3-11 .9, US
Dept. of the Army, Pentagon, Washington, DC (approved for
public release, distribution unlimited)
Fate Notes
Hydrolysis product, is incorporated
into moisture in air; subject to wet/dry
deposition
Hydrolysis fate of Amiton (agent
VG) is not well-characterized and it
is unclear if data for nerve agent VX
represent a reasonable surrogate.
Potential fate product; can form in
moist air; can persist as a terminal fate
product
In the absence of specific degradation
information for VMs are not assessed.
In the absence of specific degradation
information for Vsubx, fate products
are not assessed.
             a This table identifies concentrations addressing additional chemical agents and key transformation products (indented, in italics); 2 are represented by potential fate products:  nitrogen mustard, and VG; no relevant benchmarks
         were identified for VE. Some fate products are common to more than one primary contaminant while others are unique. Unless otherwise noted, concentrations represent limits for long-term exposures. EPA benchmarks are
         prioritized, with others included as further context; lower values are shown in lighter font (green). Parentheses identify derived concentrations, from related chemicals. Calculated values are rounded to two significant figures. To convert
         concentrations under standard conditions: mg/m3 = (molecular weight/24.5) x ppm. For those without relevant public benchmarks, occupational limits were also assessed to provide initial context. For example, although no public
         guideline was found specifically for HN-2, the CDC identifies a workplace airborne exposure limit (AEL) of 3 ug/m3 for nitrogen mustard HN-1, and the acute toxicity of HN-2 is half that of HN-1 (from the Medical Management
         Guidelines for Blister Agents, Nitrogen Mustards, ATSDR 2006). Note that the AEL is
         "a maximum concentration of an agent in air that is safe for continuous exposure during an 8-hr work day" and is considered a general term indicating a level of exposure unlikely to result in adverse health effects (NAS 2000b).
IN)
Ul

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      Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Chloropicrin

Nitrate (NO }), as N


Nitrite (NO 2), as N


Dichlorvos

Dichloroacetic add



Methanol
Phosphoric add, phosphate
Dicrotophos (Bidrin)

CASRN
76-06-2

14797-55-8


14797-65-0


62-73-7

79-43-6



67-56-1
7664-38-2
141-66-2

Water
Concn.
(mIL)
50

10,000


1,000


0.28

60



18,000
12,000
3.5

Basis
Archived Action Level,
0.05mg/L
CA Dept of Health Services
MCL, lOmg/L
(EPA Office of Water)


MCL, 1 mg/L
(EPA Office of Water)


SF, 0.29 per mg/kg-d
(EPA IRIS)

Represented by toxicity of
Haloacetic acids,
MCL, 0.06 mg/L
(EPA Office of Water)


RfD, 0.5 mg/kg-d
(EPA IRIS)
Drinking water guideline,
12 ppm
(Maui Department of Water
Supply [DOWS])
RfD, 0.0001 mg/kg-d
(EPA IRIS)

Citation/Link for Risk-Based \alue
CA Department of Health Services (2007), http://www.dhs.
ca.gov/ps/ddwem/chemicals/ AL/PDFs/archive.pdf, archived
advisory level
EPA 2004a, 1992 MCL, 10 mg/L, http://www.epa.gov/
safewater/contaminants/index.html. EPA (1991a), http://www.
epa.gov/iris/subst/0076.htm, RfD is for an infant at 0.64 L/d
(70-kg adult, 2 L/d, would be 56,000 ug/L); this value is equal
to the 1992 MCL
EPA 2004a, 1992 MCL, 1 mg/L, http://www.epa.gov/
safewater/contaminants/index.html. EPA (1997), http://www.
epa.gov/iris/subst/0078.htm, for the 10-kg child (70-kg adult, 2
L/d, would be 3,500 ug/L); this value is equal to the 1992 MCL
EPA (1993), http://www.epa.gOv/iris/subst/0 1 5 1 .htm: RfD
is 9.0005 mg/kg-d (}8 ug/L), same as MRL; EPA (2006d),
Interim Reregistration Eligibility Decision for Dichlorvos
(DDVP), http://www.epa.gov/pesticides/reregistration/REDs/
ddvp ired.pdf is OPP RfD, with chronic NOAEL of 0.05 mg/
kg-dandUFoflOO
EPA 2004a, MCL, 0.06 mg/L, http://www.epa.gov/safewater/
contaminants/index.html. On this MCL website, EPA has a
footnote for Haloacetic acids that states the MCL is used for
all the compounds in this group. EPA (2003), http://www.
epa.gov/iris/subst/0654.htm; 95% upper bound for 10'6 risk,
central tendency 2.3 ug/L; RfD 0.004 mg/kg-d is 140 ug/L; the
DWELislOOug/L
EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Maui DOWS 2004 (based on 12 ppm 85% phosphoric acid
solution as health protective, from American National Standards
Institute [ANSI] and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
EPA (1989), http://www.epa.gov/iris/subst/021 1 .htm: in EPA
2002a (OPPTS drinking water level of comparison),
http://www.epa.gov/oppsrrdl/REDs/dicrotophos ired.pdf,
chronic general population DWLOC is 1 ppb, or 1 ug/L; the
chronic drinking water level of comparison (DWLOC) for ages
1-6 is 0.2 ppb, or 0.2 ug/L
Fate Notes
Little to slow hydrolysis, with a half-
life of 1 1 yr; photolysis half-life is 3
d (surface water), with volatilization
half-life 4 hr to 5 d
Photolysis product (e.g., in open
systems); nitrogen naturally cycles in
the environment

Photolysis product (e.g., in open
systems), from nitrate; nitrogen
naturally cycles in the environment

Hydrolysis half-life is 4 d at pH 7
(decreases with increasing pH);
volatilization half-life is on the order
of months

Hydrolysis product; the
environmental half-life of this
haloacetic acid (HAA) is < 100 hr


Hydrolysis product; volatilization
half-life of 5-52 d
Terminal hydrolysis product;
phosphates can persist
Hydrolysis half-life is 72 d at 25°C
and pH 7, faster in alkaline water

IN)

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      Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Acetone
Methanol
Phosphoric acid, phosphate
Dimethyl phosphite (DMP)
Methanol
Phosphoric acid, phosphate
Ethyldichloroarsine (agent ED)
Arsenic (inorganic)
Fenamiphos
CASRN
67-64-1
67-56-1
7664-38-2
868-85-9
67-56-1
7664-38-2
598-14-1
7440-38-2
22224-92-6
Water
Concn.
(mIL)
32,000
18,000
12,000
1,500
18,000
12,000
Basis
RfD, 0.9 mg/kg-d
(EPA IRIS)
RfD, 0.5 mg/kg-d
(EPA IRIS)
Drinking water guideline,
12 ppm
(Maui DOWS)
SF, 0.0054 per mg/kg-d
(NAS)
RfD, 0.5 mg/kg-d
(EPA IRIS)
Drinking water guideline,
12 ppm
(Maui DOWS)
Citation/Link for Risk-Based \folue
EPA (2003), http://www.epa.gov/iris/subst/0128.htm
EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Maui DOWS 2004 (based on 12 ppm 85% phosphoric acid
solution as health protective, from American National Standards
Institute [ANSI] and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
NAS 2000a (Organic Phosphonates, in Toxicological Risks of
Selected Flame-Retardant Chemicals),
http://www.nap.edu/books/0309070473/html/328.html; for a
risk level of 1 0'4, this translates to 1 ,500 ug/L; note that an RfD
was also identified, as 0.12 mg/kg-d, which translates to 4,200
Fg/L
EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Maui DOWS 2004 (based on 12 ppm 85% phosphoric acid
solution as health protective, from American National Standards
Institute [ANSI] and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
No specific drinking water benchmark found;
this entry is included to introduce the fate product for which a benchmark exists
10
8.8
MCL, 0.01 mg/L (EPA Office
ofWater)
RfD, 0.00025 mg/kg-d
(EPA IRIS)
EPA (2004a),The MCL is 10 ug/L (from 50 in 2001), http://
www.epa.gov/safewater/contaminants/index.html, as is the
DWEL; the IRIS drinking water unit risk (DWUR) is 0.00005
per ug/L, 0.02ug/L for 10-6 risk level, EPA (1998), http://www.
epa.gov/iris/subst/0278.htm; 1993 RfD of 0.0003 mg/kg-d
(also 2000 CaUEPA, 1995 draft HA, 2005 MRL) gives 1 1 ug/L
(rounded)
EPA (1990), http://www.epa.gov/iris/subst/0240.htm: the
earlier 1988 HA is 2 ug/L, DWEL is 9 ug/L (EPA 2004a);
OPPTS RfD of 0.0001 mg/kg-d gives 3.5 ug/L, in EPA 1999a,
OPPTS chronic DWLOC for general public is 4 ppb; 1 ppb
(ug/L) for child (most sensitive group), EPA 2002b, http://www.
epa.gov/pesticides/reregistration/REDs/fenamiphos ired.pdf
Fate Notes
Hydrolysis product; volatilization
half-life ranges from 8 hr to
14 d, readily biodegradable (1 d
for aerobic, 5 d for anaerobic),
adsorption not significant
Hydrolysis product; volatilization
half-life is 5-52 d
Terminal hydrolysis product;
phosphates can persist
Hydrolysis half-life 10 d at 25°C,
slower in cooler water and higher
pH; forms methanol and MP,
which hydrolyzes to methanol and
phosphorous acid, which oxidizes to
phosphoric acid
Hydrolysis product; volatilization
half-life is 5-52 d
Terminal oxidation product
following MP hydrolysis to
phosphorous acid; phosphates can
persist
Poorly soluble in water, persists
1—6 d at 5— 30°C; can react to form
persistent solids
Arsenoxides/inorganic arsenic can
persist for years and can settle out
within months (surface waters)
Half-life in surface water from
oxidation and photolysis is 1 .8 d,
much shorter with irradiation (<30
min); hydrolysis is slow, with a half-
life of 200-300 d at pH 7
IN)
Nl

-------
      Table 7 Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Fenamifhos sulfoxide
Fenamifhos sulfone

Phosphoric add, phosphate
Lewisite (Lewisite-1, agent L-l)
2-Chlorovinylarsonous add (CVAA)

Lewisite oxide

Arsenic (inorganic)


Lewisite (Lewisite-2, agent L-2)
Arsenic (inorganic)
CASRN
31972-43-7
31972-44-8

7664-38-2
541-25-3
85090-33-1

3088-37-7

7440-38-2


40334-69-8
7440-38-2
Water
Concn
(mIL)
(8.8)
(8.8)

12,000
3.5
(3.5)

(3.5)

10


(3.5)
10
Basis
Represented by IRIS RfD of
the parent, see previous entry
(EPA IRIS)

Drinking water guideline,
12 ppm
(Maui DOWS)
Estimated RfD, 0.0001 mg/
kg-d
(Army, NAS and Opresko et
al.)
Represented by toxicity of the
parent, as above
(Army, NAS and Opresko et
al.)

Represented by toxicity of
parent, as above
(Army, NAS and Opresko et
al.)
MCL, 0.01 mg/L (EPA Office
ofWater)


Protectively bounded by the
estimated RfD for L-l (above)
(Army, NAS and Opresko et
al.)
MCL, 0.01 mg/L (EPA Office
ofWater)
Citation/Link for Risk-Based \alue
EPA (1990), http://www.epa.gov/iris/subst/0240.htm. and
2002b (conservatively represented by above); based on same
excretion pattern, metabolites, from IPCS 1 997,
http://www.inchem.org/documents/impr/impmono/v097pr06.
htm: also note OPPTS child DWLOC of 1 ug/L above
Maui DOWS 2004 (based on 12 ppm 85% phosphoric acid
solution as health protective, from American National Standards
Institute [ANSI] and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
Opresko et al. 2001 . Chemical Warfare Agents: Current Status
of Oral Reference Doses. Rev Environ Contam Toxicol 172:65—
85. According to this source, the estimated RfD for Lewisite is
"appropriate when presence of L, CVAA, or Lewisite Oxide is
known", (note NAS considered a value 10 times lower)
Opresko et al. 2001 (as above), based on no appreciable
difference in toxicity between L-l and metabolite/LO
equilibrium mixture, Noblis 2005,
http://www.noblis.org/ChemistrvOfLLewisite.htm

Opresko et al. 2001, and per no appreciable toxicity difference,
Noblis (2005),
http://www.noblis.org/ChemistrvOfLLewisite.htm

EPA (2004a), New MCL is 10 ug/L (from 50 in 2001),
http://www.epa.gov/safewater/contaminants/index.html, as
is the DWEL; the IRIS DWUR is 0.00005 per ixg/L, 0.02
|jLg/L for 10'6 risk level, EPA (1998), http://www.epa.gov/iris/
subst/0278.htm; 1993 RfD of 0.0003 mg/kg-d (also 2000 Call
EPA, 1995 draft HA, 2005 MRL) gives 1 1 ug/L (rounded)
Opresko et al. 2001 (see L-l above; L-2 and L-3 are less toxic);
estimated RfD
EPA (2004a) New MCL is 10 ug/L (from 50 in 2001), http://
www.epa.gov/safewater/contaminants/index.html, as is the
DWEL; IRIS DWUR is 0.00005 per ug/L. 0.02 ug/L for 10'6
risk level, EPA (1998), http://www.epa.gov/iris/subst/0278.htm:
1993 RfD of 0.0003 mg/kg-d (also 2000 CalJEPA, 1995 draft
HA, 2005 MRL) gives 1 1 ug/L (rounded)
Fate Notes
Oxidation products; the sulfoxide
further oxidizes to the sulfone, and
persistence can be similar to the
parent

Terminal hydrolysis product;
phosphates can persist
Slightly soluble; hydrolyzes quickly
with a half-life of <2 min to
2-chlorovinylarsonous acid and HC1;
the volatilization half-life is 8 hr to
1 wk
Primary hydrolysis product of L-l;
undergoes dehydration to form
lewisite oxide (LO) and
LO polymers; slightly more
environmentally stable than the
parent lewisite, http://www.noblis.
org/ ChemistrvOfLLewisite.htm
Hydrolysis product of
2-chlorovinylarsonous acid, can
dehydrate to lewisite oxide polymer;
persists
Organic and inorganic products
convert to arsenite and arsenate, can
persist for years and settle out in
months (surface waters)

Hydrolyzes more slowly than L-l to
form HC1 and
bis(2-chlorovinyl)arsonous acid
Organic and inorganic products
convert to arsenite and arsenate, can
persist for years and settle out in
months (surface waters)
IN)
00

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Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Lewisite (Lewisite-3, agent L-3)
Methyl parathion



p-Nitrophenol
(or para-nitrophenol)


Methyl paraoxon
Methanol
Phosphoric acid, phosphate
Mevinphos

Methanol
Phosphoric acid, phosphate
CASRN
40334-70-1
298-00-0



100-02-7



950-35-6
67-56-1
7664-38-2
7786-34-7

67-56-1
7664-38-2
Water
Concn.
(mIL)
(3.5)
8.8



280



(0.88)
18,000
12,000
8.8

18,000
12,000
Basis
Protectively bounded by the
estimated RfD for L-l (above)
(Army, Opresko et al.)
RfD, 0.00025 mg/kg-d
(EPA IRIS)



RfD, 0.008 mg/kg-d
(EPA Region 6) HA, lifetime,
0.06 mg/L
(EPA Office of Water)

RfD for parathion above,
toxicity-scaled (*• 1 0)
(EPA IRIS)
RfD, 0.5 mg/kg-d
(EPA IRIS)
Drinking water guideline,
12 ppm
(Maui DOWS)
RfD, 0.00025 mg/kg-d
(EPA OPPTS)

RfD, 0.5 mg/kg-d
(EPA IRIS)
Drinking water guideline,
12 ppm
(Maui DOWS)
Citation/Link for Risk-Based \alue
Opresko et al. 2001 (see L-l above; L-2 and L-3 are less toxic);
estimated RfD
EPA (1991 a), http://www.epa.gov/iris/subst/0174.htm: EPA
2004a (same RfD, DWEL 9 ug/L, and 1988 HA 2 ug/L),
http://www.epa.gov/waterscience/criteria/drinking/standards/
dwstandards.pdf; MRL of 0.0003 mg/kg-d is 1 1 ug/L (10.5)
(from 2001); note EPA (OPPTS) 2003b, http://www.epa.
gov/oppsrrdl/REDs/methvlparathion ired.pdf, chronic RfD
of 0.0002 mg/kg-d, gives 7 ug/L; with safety factor 10, OPPTS
chronic population-adjusted dose is 0.7 ug/L and chronic child
DWLOC is 0.18 ug/L (1999)
EPA Region 6 (2007) http://www.epa.gov/earthlr6/6pd/rcra c/
pd-n/screenvalues.pdf; also a HA, established in 1992, of 0.06
mg/L, http://www.epa.gov/waterscience/criteria/drinking/
standards/dwstandards.pdf, report also lists RfD 0.008 mg/kg-d,
for 280 ug/L (no RfD is in IRIS), and DWEL of 300 ug/L
EPA 2004a (as above) and Cal/EPA 1999 (Scientific Review
Panel, Methyl Parathion), http://www.arb.ca.gov/srp/srp3.pdf:
judged 1 Ox more toxic than parent (inhalation, but per oral)
scaled from IRIS RfD
EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Maui DOWS 2004 (based on 12 ppm 85% phosphoric acid
solution as health protective, from American National Standards
Institute [ANSI] and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
EPA 2000b (chronic RfD, perNOAEL 0.025 mg/kg-d),
http://www.epa.gov/oppsrrdl/REDs/0250tred.pdf

EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Maui DOWS 2004 (health-based level for 85% phosphoric
acid solution, per ANSI and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
Fate Notes
Among agents, rated as persistent
at 1—3 d; resists hydrolysis but
volatilizes
Hydrolysis half-life can be <1
to 4 wk or more, depending
on temperature, pH, and other
system conditions; forms para-
nitrophenol (4-nitrophenol) and
dimethylphosphorothioic acid

Primary hydrolysis product, reduces
to p-aminophenol; photolysis half-
life in surface water is 6.7 d at pH 7

Oxidation product; hydrolyzes
within days at pH 8.5, much faster
than the parent methyl parathion
Hydrolysis product; volatilization
half-life is 5-52 d
Terminal hydrolysis product;
phosphates can persist
Hydrolysis half-life is 35 d at pH 7,
1 20 d at pH 6; hydrolyzes to methyl
acetoacetate, dimethyl phosphate,
and the two compounds below
Hydrolysis product; volatilization
half-life is 5-52 d
Terminal fate product; phosphates
can persist

-------
Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Mustard, sulfur (agents H and HD
[distilled H])
Thiodiglycol(TDG)
Mustard mlf oxide


Mustard sulfone


Divinyl sulfone



Mustard, sulfur, distilled, with T
(agent HT: Mixture of 60% HD,
40% T)
(same 4 fate products as H,
repeat from above)
CASRN
505-60-2
111-48-8
5819-08-9


471-03-4


77-77-0



Agent T =
CAS 6392-89-
8; Agent HD =
CAS 505-60-2
Water
Concn
(mIL)
0.25
14,000
(0.25)


(0.25)


(0.25)



0.25

Basis
Estimated RfDe, 0.000007
mg/kg-d
(Opresko et al./Army)
RfD, 400 ug/kg-d (Reddy et al.
2005 andTalmage et al., 2007)
Protectively represented by
estimate RfD for the parent H,
0.000007 mg/kg-d
(Opresko et al./Army)
Protectively represented by
estimated RfD for the parent
H, 0.000007 mg/kg-d
(Opresko et al./Army)
Protectively represented by the
estimated RfD for H above,
0.000007 mg/kg-d
(Opresko et al./Army)
Estimated RfD, 0.000007 mg/
kg-d (Opresko et al./CDC)

Citation/Link for Risk-Based \alue
Opresko et al. 2001 . Chemical Warfare Agents: Current Status
of Oral Reference Doses. Rev Environ Contam Toxicol 172:65-
85 estimated RfD; the intermediate MRL of 0.07 ug/kg-d, is lOx
higher (2003), from ATSDR 2005, http://www.atsdr.cdc.gov/
mrls.html
Reddy, G, AA Major and GJ Leach. 2005. Toxicity Assessment
of Thiodiglycol. Internal. J. Toxicol. 24:435^42; Talmage
et al. (2007). The Fate of Chemical Warfare Agents in the
Environment, p. 89—125, as cited in TC Marrs, RL Maynard
and F Sidell (eds.) ChemiallWarfare Agents: Toxicology and
Treatment (2nd Edition), http://www.wiley.com/WileyCDA/
WilevTitle/productCd-0470013591.html.
Opresko et al. 2001 (as for sulfur mustard above),
http://www.ncbi. nlm.nih.eov/entrez/querv.fcei?cmd=Retrieve&
db=PubMed&list uids=9597943&dopt=Abstract
(moderately toxic, rat/ mouse acute toxicity lower than H)
Opresko et al. 2001 (as for sulfur mustard above),
http://www.ncbi. nlm.nih.eov/entrez/querv.fcgi?cmd=Retrieve&
db=pubmed&dopt=Abstract&list uids=9597943&querv hl=l
(the sulfoxide is moderately toxic, with rat and mouse acute
toxicity lower than for H)
Opresko et al. 2001 (as above), http://www.ncbi.nlm.nih.gov/
entrez/querv.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract
&list uids=9597943&querv hl=l (rat oral LJX0 is half that for
H)
Opresko et al. 2001; CDC 2004, http://www.cdc.gov/nceh/
demil/files/Federal%20Reeister%20Mustard%20AEL%205
2004.pdf: CDC (2004) points out that "... toxicity data forT
are inadequate for setting exposure limits. . . . For sulfur mustard
and T mixtures, . . . monitoring for sulfur mustard alone should
be sufficient under most circumstances to prevent exposure to
it."
Fate Notes
Hydrolysis half-life is 4—8 min at
25°C in distilled water, decreases
with increasing temperature, is
limited by slow dissolution rate and a
freezing point of 14°C; volatilization
half-life is 2-20 d
Primary hydrolysis product of H (via
hemisulfur mustard intermediate),
along with HC1; hydrolysis half-life
is 6 wk
Oxidation product, notably in water
with chlorine/hypochlorite, persists
at least 1—2 d; resists hydrolysis in
natural systems
Formed by further oxidation of
mustard sulfoxide under more severe
conditions; persistence is as for the
sulfoxide, at least 1—2 d in highly
oxidizing conditions
Product of mustard sulfone
dehydrochlorination in weakly
alkaline solution; volatilizes from
surface water, half-life 1—10 d
For largest fraction (60%), same fate
as for H; see entries above forTDG,
sulfoxide, and sulfones;
T hydrolyzes to other compounds
for which no applicable chronic
public benchmarks were found

-------
      Table 7 Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water
Chemical
Nicotine




Phorate (Thimet)



Phorate sulfoxide

Phorate sulfone

Hydrogen sulfide (H2S)



Hydrogen mlfate (H2SO4)
as mlfate (CAS 14808 79 8)

Formaldehyde
Sarin (agent GB)
CASRN
54-11-5




298-02-2



2588-03-6

2588-04-7

7783-06-4



7664-93-9

50-00-0
107-44-8
Water
Concn.
(mIL)
(70)




7



6

6

200



250,000

7,000
0.7
Basis
Intake-adjusted from 2 ppm
tolerance for food residues
(EPA OPPTS)



RfD, 0.0002 mg/kg-d
(EPA HEAST)



RfD, 0.00017 mg/kg-d
(EPA OPP)

RfD, 0.00017 mg/kg-d
(EPA OPP)

Suggested drinking water limit
based on health effects,
0.2 ppm (MDCH)



SMCL for Sulfate, 250 mg/L
(EPA Office of Water)

RfD, 0.2 mg/kg-d (EPA IRIS)
Estimated RfD, 0.00002 mg/
kg-d (Army, Opresko et al
2001)
Citation/Link for Risk-Based \alue
EPA 2002c (40 CFR 180.167; cucumber, lettuce, tomato),
http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?YEAR=2002
&TITLE=40&PART= 1 80&SECTION= 1 67&SUBPART=&T
YPE=TEXT indicator using 52 g/d per capita intakes (assumed
taken in within 2 L ingested), from EPA 1997a, (Tables 9-25)
http://cfpub.epa.gov/ncea/cfm/recordisplav.cfm?deid= 1 2464

EPA (2007a) RfD on HEAST, http://epa-heast.ornl.gov/
Phorate.shtml; also DWLOC for child (chronic) in EPA 2001
(for the most sensitive group, child age 1—6), http ://www.epa.
gov/oppsrrdl/REDs/phorate ired.pdf; note the OPP RfD of
0.0005 mg/kg-d would give 18 ug/L, EPA 1999c (Human
Health Risk Assessment: Phorate), http://www.epa.gov/pesticides/
reregistration/phorate/; chronic population-adjusted dose gives
6 ug/L
EPA1998b;
http://www.ecologic-ipm.com/PDP/Table3 1 998.pdf

EPA1998b;
http://www.ecologic-ipm.com/PDP/Table3 1 998.pdf

Michigan Department of Community Health (MDCH)
(undated, accessed 2006), drinking water limit,
http://www.michigan.gov/documents/hvdrogensulfide
factsheet 6538 7.pdf (note that the EPA RfD of 0.003 mg/
kg-d that had translated to 105 ug/L was withdrawn in 2003,
http://www.epa.gov/IRIS/subst/0061.htm)

EPA 2004a, http://www.epa.gov/waterscience/criteria/drinking/
standards/dwstandards.pdf, listed in the Drinking Water
Advisory Table
EPA (1990), http://www.epa.gov/iris/subst/04l9.htm; this is
also the DWEL and the 1 999 MRL; the 1 993 draft HA is 1
mg/L, or 1,000 ug/L (EPA 2004a)
Opresko et al. 2001 (same reference as for Lewisite)
Fate Notes
Miscible in water but not expected
to hydrolyze (main change is from
biodegradation)



Oxidizes to the sulfoxide and
sulfone; hydrolysis half-life is
3—61 d; forms diethyldisulfide,
formaldehyde and hydrogen sulfide;
volatilization half life is 2—15 wk

Oxidation product; more persistent
than the phorate parent

Oxidation product, more persistent
than the phorate parent

Hydrolysis product, oxidizes to the
sulfate; hydrolysis half-life is 50 d at
25°C and pH 8



Terminal product, sulfate can persist

Hydrolysis product, can oxidize
slowly to formic acid, converts to
paraformaldehyde and polymers
(can biodegrade in a few days)
Hydrolysis half-life is 24 h at 25°C
and pH 7.5, faster at higher pH;
forms HP and IMPA, then MPA
and isopropanol; does not volatilize
from water
CO

-------
      Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water (Set 1)a
tO
IN)
Chemical
Hydrofluoric acid, HP, as F

Isopropyl methylphosphonic acid
(IMPA)

Methylphosphonic acid (MPA)


Soman (agent GD)
Hydrofluoric acid, HP, as F


Methylphosphonic Of id (MPA)



CASRN
7664-39-3

1832-54-8

993-13-5


96-64-0
7664-39-3


993-13-5



Water
Concn.
(mIL)
4,000

3,500

700


0.14
4,000


700



Basis
MCL, 4 mg/L (EPA Office of
Water) (for Fluoride)

RfD, 0.1 mg/kg-day
(EPA IRIS)

Estimated RfD,
0.020 mg/kg-d
(Munro et al./Army/Talmage et
al. 2007)
Estimated RfD, 0.000004 mg/
kg-d (Army, Opresko et al.
2001)
MCL, 4 mg/L (EPA Office of
Water) (for Fluoride)


Estimated RfD,
0.020 mg/kg-d (Munro et al./
Army/Talmage et al. 2007)


Citation/Link for Risk-Based \alue
EPA 2004a, MCL is 4 mg/L or 4,000 ug/L, http://www.epa.
gov/safewater/contaminants/index.html; IRIS RfD of 0.06 mg/
kg-d, EPA (1989), http://www.epa.gov/iris/subst/0053.htm. for
soluble F; more recent non-EPA value is lower, MRL 0.05 mg/
kg-d, for Sodium Fluoride, 1,800 ug/L, ATSDR 2003a,
http://www.atsdr.cdc.2ov/toxprofiles/tpl l-c2.pdf; Cal/
EPA2005b, RfD 0.04 mg/kg-d is 1,400 ug/L,
http://www.arb.ca.gov/toxics/healthval/contable.pdf
EPA (1993), http://www.epa.gov/iris/subst/0530.htm: Same
value also referenced in: Talmage et al (2007) . The Fate
of Chemical Warfare Agents in the Environment, p. 89-
125, as cited inTC Marrs, RL Maynard and F Sidell (eds.)
Chemical Warfare Agents: Toxicology and Treatment (2nd
Edition), http://www.wiley.com/WileyCDA/WileyTide/
productCd-0470013591.html. DWEL 4,000; 1992 HA 0.7
mg/L, 700 ug/L (EPA 2004a)
Munro et al. 1999 (RfD per structural similarity),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89—125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/DroductCd-0470013591.html.
Opresko et al. 2001 (same reference as for lewisite)
EPA 2004a, MCL is 4 mg/L or 4,000 ug/L, http://www.epa.
2ov/safewater/contaminants/index.html; IRIS RfD of 0.06 m2/
kg-d, EPA (1989), http://www.epa.gov/iris/subst/0053.htm. for
soluble F; more recent non-EPA value is lower, MRL 0.05 mg/
kg-d, , for Sodium Fluoride, 1,800 ug/L, ATSDR 2003a,
http://www.atsdr.cdc.gov/toxprofiles/tpl l-c2.pdf; Cal/EPA
2005b, RfD 0.04 mg/kg-d is 1,400 ug/L,
http://www.arb.ca.2ov/toxics/healthval/contable.pdf
Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.2ov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talma2e et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89—125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.

Fate Notes
Primary hydrolysis product of GB;
can form fluoride salts that can
persist, as well as an ion pair that is
unique to HF
(F-H*-OH2)

Primary hydrolysis product of GB;
predicted half-life >1,900 yr

Hydrolysis product, forms very
slowly from IMPA; chemically stable
in the environment

Hydrolysis can be 5x slower than GB
(e.g., half-life could be 5 d); forms
HF and pinacolyl MPA; half-life for
volatilization from water is 1 1—83 d
Primary hydrolysis product of GD;
can form fluoride salts that can
persist, as well as an ion pair that is
unique to HF
(F-H*-OH2)

Hydrolysis product, forms very
slowly from pinacolyl MPA; is
chemically stable in environment



-------
Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water (Set 1)a
Chemical
Strychnine
Tabun (agent GA)
Hydrogen cyanide (HCN)
Cyanide (CN),free
Ammonia (NH )
(same 2 fate products as
shown for chlaropicrin:
nitrate and nitrite;
repeat from above)
Phosphoric acid, phosphate
Tetraethyl pyrophosphate (TEPP)
Phosphoric acid, phosphate
Trimethyl phosphite (TMP)
Dimethyl phosphite (DMP)
Methanol
CASRN
57-24-9
77-81-6
74-90-8
57-12-5
7664-41-7
7664-38-2
107-49-3
7664-38-2
121-45-9
868-85-9
67-56-1
Water
Concn.
(mIL)
11
1.4
700
200
34,000
12,000
Basis
RfD, 0.0003 mg/kg-d
(EPA IRIS)
Estimated RfD, 0.00004 mg/
kg-d (Army, Opresko et al.
2001)
RfD, 0.02 mg/kg-day
(EPA IRIS)
MCL, 0.2 mg/L (EPA Office
ofWater)
RfD, 34 mg/L
(EPA HEAST)
Drinking water guideline,
12 ppm
(Maui DOWS)
Citation/Link for Risk-Based Value
EPA (1988), http://www.epa.gov/iris/subst/0103.htm
Opresko et al. 2001 (same reference as for lewisite)
EPA (1993), http://www.epa.gov/iris/subst/0060.htm: based on
cyanide toxicity
EPA (2004a) 1992 cyanide MCL is 0.2 mg/L, or 200 ug/L, from
http://www.epa.gov/safewater/contaminants/index.html; IRIS
RfD is 0.02 mg/kg-d, EPA (1993), http://www.epa.gov/iris/
subst/0031 .htm; the RfD is for cvanide; the DWEL is 800 ug/L
and lifetime HA is 200 ug/L, identified as under review in EPA
2004a (listed under cyanide with the CAS number 143-33-9 for
sodium cyanide)
EPA (2007a), HEAST online database, http ://epa-heast.ornl .gov/
Ammonia.shtml; also there is a HA of 30 mg/L from EPA (1992),
lifetime HA, listed in EPA 2004a
Maui DOWS 2004 (health-based level for phosphoric acid, from
ANSI and National Sanitation Foundation),
http://mauiwater.org/phosphates.html
No specific drinking water benchmark found;
this entry is included to introduce the fate product for which a benchmark exists
12,000
(1,500)
1,500
18,000
Drinking water guideline,
12 ppm (Maui DOWS)
Represented by DMP, from
oral SF per mg/kg-d
(NAS)
SF, 0.0054 per mg/kg-d
(NAS)
RfD, 0.5 mg/kg-d
(EPA IRIS)
Maui DOWS 2004 (as above under HCN entry),
http://mauiwater.org/phosphates.html
NAS 2000a (Organic Phosphonates, in Toxicolagical Risks
of Selected Flame-Retardant Chemicals),
http://www.nap.edu/books/0309070473/html/328.html
NAS 2000a (as described in main entry earlier in table),
http://www.nap.edu/books/0309070473/html/328.html
EPA (1993), http://www.epa.gov/iris/subst/0305.htm
Fate Notes
Poorly soluble, and essentially no
hydrolysis at pH 5, 7, 9; likely
removal process is adsorption
Hydrolysis half-life is 8.5 hr at pH
7; lower in acidic, basic water
Primary hydrolysis product; can
form free CN, as well as CK with
humic acid and chlorine residuals
Most will exist as HCN (>99%
at pH<7); hydrolyzes slowly to
formamide, then formic acid and
ammonia; much will volatilize
at pH <9.2, with half-lives of 22
and 1 10 hr for 25 and 200 ug/L,
respectively
Dissolves readily and forms the
ammonium ion (microbes can
convert to nitrate/nitrite, e.g., in
surface waters/reservoirs; see those
entries under chloropicrin above
and for CK, CN in Table 8)
Terminal product of GA
hydrolysis; phosphates can persist
Hydrolyzes to diethyl phosphate
with a 7-hr half-life, then to
ethanol and phosphoric acid
Terminal hydrolysis product,
phosphates can persist
Hydrolyzes to DMP, methanol
(<20 min half-life), then to MP,
methanol, and phosphorous acid
Hydrolyzes to methanol, MP,
phosphoric acid (see main entry)
Hydrolysis product of TMP, DMP,
and MP; volatilization half-life is
5-52 d

-------
Table 7  Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation Products in Water (Set 1)a
Chemical
Phosphoric add, phosphate
VX,or:
O-ethyl-S-[2-(diisopropylamino)ethyl]
methylphosphonothioate
S-[2-(diisopropylamino)ethyl]
methylphosphonothioate (EA 2192)



Diisopropyl ethyl mercaptoamine
(DESH)


O-ethyl methylphosphonic add
(EMPA)



Methylphosphonic acid (MPA)



CASRN
7664-38-2
50782-69-9
73207-98-4



5842-07-9


1832-53-7



993-13-5



Water
Concn
(mIL)
12,000
0.021
0.021



130


980



700



Basis
Drinking water guideline,
12ppm (MauiDOWS)
Estimated RfD, 0.0000006
mg/kg-d (Opresko et al. 2001)
Estimated RfD,
0.0006 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)


Estimated RfD,
3.8 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)

Estimated RfD,
28 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)


Estimated RfD,
20 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)


Citation/Link for Risk-Based \alue
Maui DOWS 2004 (as above under HCN entry),
http://mauiwater.org/phosphates.html
Opresko et al. 2001
Munro et al. 1 999 (per similar chemical; nearly as toxic at VX),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89-125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.

Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89-125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.
Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.2ov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89-125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.

Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89-125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.

Fate Notes
Oxidation product of phosphorous
acid; phosphates can persist
Dissolves rapidly; can slowly
decompose through ion-catalyzed
hydrolysis (to EA 2192), with a
half-life of 17^2 d at pH 7, 25°C
Primary hydrolysis product,
about half follows this pathway in
distilled water; hydrolysis half-life
is >1,000 hr; is more stable than
VX

Primary hydrolysis product;
in distilled water about a third
follows this pathway; is more
stable than VX
Primary hydrolysis product, as
for DESH; estimated hydrolysis
half-life is >330,000 yr (assuming
first-order kinetics)

Hydrolysis product forms very
slowly from EMPA; MPA itself is
chemically stable



-------
         Table 7   Risk-Based Criteria for the Initial Priority Chemicals and Their Key Transformation  Products in Water  (Set  1)a
                      Chemical
CASRN
Water
Concn
 (mIL)
           Basis
        Citation/Link for Risk-Based Value
         Fate Notes
               Methylphosphonic acid (MPA)
 993-13-5
   700
Estimated RfD,
20 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)
Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
                                                                                                       munrotabl6B.GIF: Talmage et al (2007). The Fate of Chemical
                                                                                                       Warfare Agents in the Environment, p. 89-125, as cited in TC
                                                                                                       Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfareAgents:
                                                                                                       Toxicology and Treatment (2nd Edition), http://www.wiley.com/
                                                                                                       WileyCDA/WileyTitle/productCd-0470013591.html.
Hydrolysis product forms very
slowly from EMPA; MPA itself is
chemically stable
            2-Diisofrofylaminoethanol
  96-80-0
  290
Estimated RfD,
8.4 ug/kg-d (Munro et al./
Army/Talmage et al. 2007)
Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89-125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WileyCDA/WileyTitle/productCd-0470013591.html.
Primary hydrolysis product of VX,
stability expected to be similar to
DESH
             O-ethylmethylphosphonothioic acid
            (EMPTA)
18005-40-8
  250
Estimated RfD,
7 ug/kg-d (Munro et al./Army/
Talmage et al. 2007)
Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF: Talmage et al. (2007). The Fate of Chemical
Warfare Agents in the Environment, p. 89—125, as cited in TC
Marrs, RL Maynard and F Sidell (eds.) ChemicalWarfare Agents:
Toxicology and Treatment (2nd Edition), http://www.wiley.com/
WilevCDA/WilevTitle/productCd-0470013591.html.
Primary hydrolysis product of VX,
stability expected to be similar to
DESH
            a This table summarizes risk-based criteria relevant to the 23 initial priority chemicals and their key transformation products (indented in italics), including fate products repeated for several threat contaminants. Two of the primary
         chemicals — ED and TEPP — are represented by fate products, and the value for a third (nicotine) was derived from an oral benchmark for residues. Some fate products are common to more than one threat contaminant, while other
         concentrations are unique.
            Parentheses indicate values determined from other chemicals, including as scaled from parent compounds. Calculated values are rounded to two significant figures.
            Unless otherwise noted, concentrations represent limits for long-term exposures. EPA benchmarks are prioritized, with others included as further context; lower values shown in lighter font (green). For chemicals with both a cancer
         and noncancer toxicity value in IRIS for a given route, the lower corresponding concentration is used. For example, the arsenic RfD of 0.0003 mg/kg-d translates to 10.5 ug/L (rounded to 11), while the concentration corresponding to
         the 10'6 risk level is lower (0.02 ug/L), so that value is listed above. Limits based only on aesthetics and not health are not presented here (e.g., secondary maximum contaminant levels based on taste, such as 250,000 ug/L for chloride,
         which would have applied to the common fate product hydrogen chloride if it were health-based).
            For hydrogen sulfide, 0.2 ppm is the limit suggested by the State of Michigan based on health effects (from MDCH, accessed 2006). Note for TEPP, the value based on a preliminary internal evaluation of limited data could be
         somewhat below 9 ug/L. For nicotine, the 2 ppm tolerance for residue on cucumbers, lettuce, and tomatoes was combined with information on the average intakes of these foods (52 g/d, from 5.2, 16.3, and 30.2 g/d, respectively;
         EPA 1997a). Assuming no hydrolysis, scaling this amount to an ingestion rate of 2 L/d would translate to 52 ug/L as a possible indicator (to be refined in further evaluations, e.g., to also consider relative oral bioavailability).
CO

-------
J{J    Table 8 Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Water
Chemical
Arsine (agent SA)
Arsenic (inorganic)
Cyanogen chloride (agent CK)
Ammonia (NH )
Nitrate (NO }), as N
Nitrite (NO;), as N
CAS RN
7784-42-1
7440-38-2
506-77-4
7664-41-7
14797-55-8
14797-65-0
Water
Concn.
(mIL)
Basis
Citation/Link for Risk-Based Value
No specific drinking water benchmark found; converts quickly in water;
this entry is included to introduce the fate product for which a benchmark exists
10
1,800
34,000
10,000
1,000
MCL, 0.01 mg/L
(EPA Office of
Water)
RfD, 0.05 mg/kg-d
(EPA IRIS)
RfD, 34 mg/L
(EPA HEAST)
MCL, lOmg/L
(EPA Office of
Water)
MCL, 1 mg/L
(EPA Office of
Water)
EPA (2004a),Thc MCL is 10 ug/L (from 50 ug/L in 2001),
http://www.epa.gov/safewater/contaminants/index.html,
as is the DWEL; the IRIS DWUR is 0.00005 per ug/L,
0.02ug/L for 10-6 risk level, EPA (1998), http://www.
epa.gov/iris/subst/0278.htm; 1993 RfD of 0.0003 mg/
kg-d (also 2000 CalJEPA, 1995 draft HA, 2005 MRL) gives
1 1 ug/L (rounded)
EPA (1995a) http://www.epa.gov/IRIS/subst/0024.
htm: Additional toxicity values include 0.03 mg/kg-d
from Opresko et al. (1998), http://chppm-www.apgea.
armv.mil/chemicalagent/PDFFiles/Opreskoetall998
EstimatingCWRfDs RECT.pdf; there is also a HA RfD
of 0.05 mg/kg-d, which is the same as the IRIS RfD, EPA
2004a (Drinking Water Standards and Health Advisories,
under review; note DWEL is 2,000 ug/L), http://www.epa.
gov/waterscience/criteria/drinking/standards/dwstandards.
pdf: CHPPM RfD (ingestion) is 0.750 mg/L, or 750 ug/L,
in CHPPM 1998, http://chppm-www.apgea.army.mil/dts/
docs/detck.pdf

EPA (2007a), HEAST online database, http://epa-heast.
ornl.gov/Ammonia.shtml; also there is a HA of 30 mg/L
from EPA (1992) lifetime HA, EPA 2004a
EPA 2004a, 1992 MCL, 10 mg/L, http://www.epa.gov/
safewater/contaminants/index.html. EPA (1997), http://
www.epa.gov/iris/subst/0078.htm, for 10-kg child (70-kg
adult, 2 L/d, is 56,000 ug/L)
EPA 2004a, 1992 MCL, 1 mg/L, http://www.epa.gov/
safewater/contaminants/index.html. EPA (1997). http://
www.epa.gov/iris/subst/0078.htm, for the 10-kg child
(70-kg adult, 2 L/d, would be 3,500 ug/L)
Fate Notes
Hydrolyzes rapidly in light, to elemental
arsenic; oxidizes to arsenite, arsenate (note
that in the dark with no air at 15.5 °C, 1/3
hydrolyzes within 5 hr and 2/3 within 1 d)
Hydrolysis products; arsenic compounds can
persist for years, can settle out within months
(e.g., in surface waters)
Significant hydrolysis to cyanic and
hydrochloric acids, 5-hr half-life at pH 8.6,
20°C; slower in neutral to acid pH; cyanic acid
hydrolyzes to CO2 and ammonium chloride/
NH ; note CK converts to cyanide in the body,
but not via hydrolysis in water
Dissolves readily and forms the ammonium ion
(microbes can convert to nitrate/nitrite, e.g., in
surface waters/reservoirs)
Oxidation product of ammonia, nitrogen
naturally cycles in the environment
Oxidation product of ammonia, nitrogen
naturally cycles in the environment

-------
        Table 8  Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Water
                    Chemical
CASRN
Water
Concn
 (mIL)
     Basis
    Citation/Link for Risk-Based Value
              Fate Notes
         Cyclohexyl sarin (agent GF, or
         cyclosarin)
 329-99-7
                 0.14
           Estimated RfD,
           0.000004 ug/kg-d
           (Army CHPPM)
                  CHPPM (2006), Chemical Warfare Agent Criteria,
                  Summary Information, March 2006, http://
                  usachppm.apgea.armv.mil/chemicalagent/PDFFiles/
                                                   Hydrolysis half-life 42 hr at 25°C (distilled
                                                   water); forms HF and cyclohexyl MPA, then
                                                   MPA and cyclohexanol (like GB)
                                                                                        ChemicalWarfareAgentCriteria SummaryMar2006.pdf,
                                                                                        GD and GF should have the same toxicity value, 4E-6
                                                                                        mg/kg-d.
           Hydrofluoric acid, HF, as F
 7664-39-3
  4,000
MCL, 4 mg/L (EPA
Office of Water) (for
Fluoride)
EPA 2004a, MCL is 4 mg/L or 4,000 ug/L,  http://www.
epa.gov/safewater/contaminants/index.html: IRIS RfD
of 0.06 mg/kg-d, EPA (1989), http://www.epa.gov/iris/
subst/0053.htm, for soluble F; a more recent non-EPA
value is lower, the 2003 MRL of 0.05 mg/kg-d, for Sodium
Fluoride, (gives 1,800 ug/L), in ATSDR2005, http://-
Primary hydrolysis product of GF; can form
fluoride salts that can persist, as well as an ion
pair that is unique to HF
                                                                                        atsdr.cdc.gov/mrllist 12 05.pdf; Cal/EPA, RfD 0.04 mg/
                                                                                        kg-d is 1,400 ug/L, 2005b, http://www.arb.ca.gov/toxics/
                                                                                        healthval/contable.pdf
           Methylphosphonic acid (MPA)
 993-13-5
   700
Estimated RfD,
20 ug/kg-d
(Army CHPPM/
Munro et al./
Talmage et al. 2007)
CHPPM (1999), Suggested Interim Estimates of the
Reference Dose (RfD) and Reference Concentration (RfC)
for Certain Key Breakdown Products of Chemical Agents,
as cited in Derivation of HBESLs for CWA, Appendix F,
March 1999; Munro et al. 1999 (per similar chemical),
http://ehp.niehs.nih.gov/members/1999/107p933-
974munro/munrotabl6B.GIF: Talmage et al (2007). The
Fate of Chemical Warfare Agents in the Environment, p.
89-125, as cited inTC Marrs, RL Maynard and F Sidell
(eds.) Chemical Warfare Agents: Toxicology and Treatment
(2nd Edition), http://www.wiley.com/WileyCDA/
WilevTitle/productCd-0470013591.html.
Hydrolysis product forms very slowly from
cyclohexyl MPA; chemically stable in the
                                                                                                                                           environment
         Ethyl sarin (agent GE)
 1189-87-3
  (0.7)
Represented by
Estimated RfD
for sarin, 0.00002
mg/kg-d
(Army, Opresko et
al. 2001)
Opresko et al 2001 (taken to be represented by the RfD
forGB
Similar to GB but somewhat slower hydrolysis;
forms HF and EMPA, then MPA and ethanol
(analogous to GB)
           Hydrofluoric acid, HF, as F
 7664-39-3
  4,000
CO
Nl
MCL, 4 mg/L (EPA
Office of Water)
(for Fluoride)
EPA 2004a, MCL is 4 mg/L or 4,000 ug/L, http://www.
epa.gov/safewater/contaminants/index.html: IRIS RfD
                                            of 0.06 mg/kg-d, EPA (1989), http://www.epa.gov/iris/
                                            subst/0053.htm, for soluble F; see entry under GF above
Primary hydrolysis product of GE; can form
fluoride salts that can persist, and an ion pair
that is unique to HF (F~H*-OH2)
                                                                                        (MRL of 1,800 ug/L, for Sodium Fluoride, Cal/EPA RfD
                                                                                        gives 1,400 ug/L)

-------
     Table 8  Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Water
CO
oo
Chemical
O-ethyl methylphosphonic acid
(EMPA)


Methylphosphonic acid (MPA)



Hydrogen cyanide
(HCN, agent AC)
Cyanide (CN),free


Ammonia (NH})

Nitrate (NO- 3), as N


Nitrite (NO-), as N


CASRN
7*32-53-7


593-73-5



74-90-8
57-12-5


7664-41-7

14797-55-8


14797-65-9


Water
Concn
(mIL)
980


700



700
200


34,000

10,000


1,000


Basis

Estimated RfD,
0.028 mg/kg-d
(Munro et al./
Army/Talmage et al.
2007)

Estimated RfD,
0.020 mg/kg-d
(Munro et al./
Army/Talmage et al.
2007)

RfD, 0.02 mg/kg-d
(EPA IRIS)
MCL, 0.2 mg/L
(EPA Office of
Water)


RfD, 34 mg/L
(EPA HEAST)

MCL, lOmg/L
(EPA Office of
Water)

MCL, 1 mg/L
(EPA Office of
Water)

Citation/Link for Risk-Based \alue
Munro et al. 1999 (per similar chemical), http://ehp.
niehs.nih.aov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al. (2007). The Fate of
Chemical Warfare Agents in the Environment, p. 89—125,
as cited in TC Marrs, RL Maynard and F Sidell (eds.)
Chemical Warfare Agents: Toxicology and Treatment (2nd
Edition), http://www.wiley.com/WileyCDA/WileyTitle/
productCd-0470013591.html.
Munro et al. 1999 (per similar chemical), http://ehp.
niehs.nih.gov/members/1999/107p933-974munro/
munrotabl6B.GIF; Talmage et al. (2007). The Fate of
Chemical Warfare Agents in the Environment, p. 89—125,
as cited in TC Marrs, RL Maynard and F Sidell (eds.)
Chemical Warfare Agents: Toxicology and Treatment (2nd
Edition), http://www.wiley.com/WileyCDA/WileyTitle/
productCd-0470013591.html.

EPA (1993), http://www.epa.gov/iris/subst/0060.htm:
based on cyanide toxicity
EPA (2004a) 1992 cyanide MCL is 0.2 mg/L, or 200
ug/L, from http://www.epa.gov/safewater/contaminants/
index.html; IRIS RfD is 0.02 mg/kg-d, EPA (1993)
http://www.epa.gov/iris/subst/0031.htm, the RfD is for
cyanide; DWEL is 800 ug/L, lifetime HA is 200 ug/L
(under review per EPA 2004a; as cyanide with CAS for
sodium CN)
EPA (2007a), HEAST online database, http://epa-heast.
ornl.gov/Ammonia.shtml; also there is a HA of 30 mg/L
from EPA (1992) lifetime HA, EPA 2004a
EPA 2004a, 1992 MCL, 10 mg/L, http://www.epa.gov/
safewater/contaminants/index.html. EPA (1997), http://
www.epa.gov/iris/subst/0078.htm, for 10-kg child (70-kg
adult, 2 L/d, would be 56,000 ug/L)
EPA2004a, 1992 MCL, 1 mg/L. http://www.epa.gov/
safewater/contaminants/index.html. EPA (1997), http://
www.epa.gov/iris/subst/0078.htm, for the 10-kg child
(70-kg adult, 2 L/d, is 3,500 ug/L)
Fate Notes


Primary hydrolysis product of GE; estimated
hydrolysis half-life >330,000 yr (assuming first-
order kinetics)


Hydrolysis product forms very slowly from
EMPA; MPA itself is chemically stable in the
environment

Much volatilizes at pH <9.2, half-life of
22-1 10 hr for solutions with 25-200 ug/L;
hydrolyzes to formamide, then formic acid and
ammonia; slower hydrolysis at pH <7
Most will exist as HCN (>99% at pH<7);
hydrolyzes slowly to formamide, then formic
acid and ammonia; much will volatilize at
pH <9.2, with half-lives of 22 and 1 10 hr for
25 and 200 ug/L, respectively
Dissolves readily and forms the ammonium ion
(microbes can convert to nitrate/nitrite, e.g., in
surface waters/reservoirs)
Oxidation product of ammonia, nitrogen
naturally cycles in the environment


Oxidation product of ammonia, nitrogen
naturally cycles in the environment



-------
Table 8 Risk-Based Criteria for Additional Chemical Agents and Their Key Transformation Products in Water
Chemical
Perfluoroisobutylene (PFIB)
Hydrofluoric add, HP, as F
Red phosphorus (RP)
Phosphine
Phosphoric acid, phosphate
VG, Amiton, or:
O, O-diethyl-S-[2-(diethyl-
amino)ethyl] phosphorothioate
VM, or:
O-ethyl-S-[2-(diethylamino)ethyl]
methylphosphonothioate
CASRN
382-21-8
7664-39-3
7723-14-0
7803-51-2
7664-38-2
78-53-5
21770-86-5
Water
Concn
(mIL)
Basis
Citation/Link for Risk-Based \folue
No specific drinking water benchmark found;
this entry is included to introduce a fate product for which a benchmark exists
4,000
(0.7)
11
12,000
MCL, 4 mg/L (EPA
Office of Water) (for
Fluoride)
Protectively
represented by
RfD for white P,
0.00002 mg/kg-d
(EPA IRIS)
RfD, 0.0003 mg/
kg-d
(EPA IRIS)
Drinking water
guideline, 1 2 ppm
(Maui DOWS)
EPA 2004a, MCL is 4 mg/L or 4,000 ue/L, http://www.
epa.gov/safewater/contaminants/index.html; IRIS RfD
of 0.06 mg/kg-d, EPA (1989), http://www.epa.gov/iris/
subst/0053.htm, for soluble F; a more recent non-EPA
value is lower, the MRL of 0.05 mg/kg-d, for Sodium
Fluoride, gives 1,800 ug/L, ATSDR 2005a, http://www.
atsdr.cdc.gov/mrllist 12 05.pdf; Cal/EPA 2005b, RfD
0.04 mg/kg-d is 1,400 ug/L,
http://www.arb.ca.gov/toxics/healthval/contable.pdf

EPA (1993) (white P has the same CAS, is more toxic),
http://www.epa.gov/iris/subst/0460.htm, as a conservative
indicator for RP; other values for white P are the
earlier 1990 HA of 0.1 ug/L, and DWEL of 0.5 ug/L
(EPA 2004a); and from 1997 intermediate MKL in
ATSDR 2005, http://atsdr.cdc.gov/mrls/pdfs/mrllist 1 2
06.pdf 0.0002 mg/kg-d for white P gives 7 ug/L for that
shorter duration
EPA (1993), http://www.epa.gov/iris/subst/0090.htm:
There is also a RfD established by EPA OPP, 0.01 13
mg/kg-d, according to http://www.epa.gov/fedrgstr/EPA-
PEST/1999/Tune/Dav-09/pl4069.htm. Application of
this RfD would yield a water concentration value of 400;
therefore the IRIS RfD is the most protective value.
Maui DOWS 2004 (health-based level for phosphoric acid
from ANSI and National Sanitation Foundation),
http://mauiwater.org/phosphates.html

No direct benchmark was found. No compound-specific toxicity information for this compound is
available, so assumptions cannot be made about toxicity of Amiton relative to that of nerve agent VX.
Further, the fate and degradation of of Amiton is not well characterized; as a consequence, VGfate
product entries are not listed.
No direct benchmark was found. No compound-specific toxicity information for this compound is
available, so assumptions cannot be made about toxicity of agent VM relative to that of nerve agent
VX. Further, the fate and degradation of of agent VM is not well characterized; as a consequence,
VM fate product entries are not listed.
Fate Notes
Hydrolyzes to fluorophosgene, then HF and
C02
Hydrolysis product, forms rapidly from
fluorophosgene; can form fluoride salts that can
persist, as well as an ion pair that is unique to
HF (F-H*-OH2)
RP slowly disproportionates, hydrolyzes, and
oxidizes; forms phosphine and phosphoric
acid; reaction half-life estimated at >350 yr to
>3,500yr
Product of RP reaction with water and oxygen;
forms very slowly, limited by solubility
Oxidation product of RP; phosphates can
persist
Degradation and hydrolysis fate of VG is not
well characterized.
In the absence of specific degradation
information for agent VM, fate products are
not assessed.

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Table  8  Risk-Based Criteria for Additional Chemical Agents  and Their  Key Transformation Products in Water
             Chemical
CASRN
Water
Concn
 (mIL)
Basis
Citation/Link for Risk-Based Value
Fate Notes
 Vx, or:
  O-ethyl-5-[2-(dimethylamino) ethyl]
  methylphosphonothioate
20820-80-8  I     No specific benchmark found.
                               No compound-specific information for agent Vx is
                               available, so an assumption cannot be made about Vx
                               toxicity relative to that of agent VX. Based on liquid skin
                               exposure, Vx is less toxic than VX; Vx ingestion/absorption
                               is not readily known [Dept of Army, 2005, Potential
                               Military Chemical/Biological Agents and Compounds,
                               FM 3-11.9, US Dept. of Army, The Pentagon,
                               Washington, DC (approved for public release, distribution
                               unlimited)]. No Vx toxicity estimates are recommended at
                               this time because data are lacking. Further, in the absence
                               of specific degradation information for Vx, fate product
                               entries are not listed.
                                                                  In the absence of specific degradation
                                                                  information for agent Vx, fate products are not
    a This table identifies risk-based chronic exposure criteria relevant to additional chemical agents and their key transformation products (indented, in italics). Some agents are represented by their fate products: arsine, and PFIB.
Some fate products are common to more than one primary contaminant, while others are unique. Parentheses indicate derived concentrations, e.g., from values for other chemicals. Calculated values are rounded to two significant
figures. Unless otherwise noted, concentrations represent limits for long-term exposures. EPA benchmarks are prioritized, with others included as further context; lower values are in lighter font (green).
   For chemicals with both a cancer and noncancer toxicity value, the value corresponding to the lower concentration is shown.
   No direct chronic public benchmarks were found for additional agents beyond those represented above: nitrogen mustard, red phosphorus, tear gas, and VE. Several convert quickly to other compounds in water, so chronic
benchmarks would not be relevant. For example, tear gas can hydrolyze in minutes to 2-chlorobenzaldehyde and malononitrile (relatively toxic). Note that after being taken into the body (but not in water), tear gas is converted to
cyanide and thiocyanate.

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Table 9  Risk-Based Criteria for Additional  Industrial Chemicals and  Products in Water and Air
             Chemical
CASRN
 Water \                        Basis
Concn. i   (Priority: EPA benchmark with most recent analysis;
  (figlL)  \       MCL, then others also indicated for context)
                                                        Air  i                       Basis
                                                     Concn.!   (Priority: EPA benchmark with most recent analysis;
                                                      (figlnf) \            others also indicated for context)
Aldicarb (Temik)
 116-06-3
   35
;IRIS RfD, 0.001 mg/kg-d (1993); the DWEL is 40 ug/L;
ithe MCL of 3 ug/L has been stayed
Aldicarb sulfone (from aldicarb)
 1646-88-4
                35
         ! IRIS RfD, 0.001 mg/kg-d (1993); the DWEL is 40 ug/L;
         ithe MCL of 2 ug/L has been stayed
Aldicarb sulfoxide (from aldicarb)
 1646-87-3
         I RfD, 0.001 mg/kg-d (in EPA 2006d, 2006 Edition of the
         i Drinking Water Standards and Health Advisories (Summer
   35    12006), EPA 822-R-06-013, Office of Water, Washington,
         ;DC; http://www.epa.gov/waterscience/criteria/drinking/
         I dwstandards.pdf) and the DWEL is 40 ug/L.
Allyl alcohol
 107-18-6
   180   i IRIS RfD, 0.005 mg/kg-d (1989)
Asbestos (various forms)
 1332-21-4
         |MCL, 7 million fibers (Mf)/L (fibers >10 urn) (1991);
 7 M f/L, i is also the HA; using qualified conversion of 30 ug/m3
   (est.   iper fiber (f)/mL (or 0.00003 ug/f) from IRIS (1993) this
210ftg/L) ; translates to 210 ug/L (note that EPA 2004a indicates a
         ! concentration of 7 Mf/L for 10'6 risk)
                                                              ! IRIS IUR, 0.23 per f/mL, 0.000004 f/mL for 10'6 risk
                                                      400 f/m3, ! (1993); HA for 10'4 risk based on inhalation is 7 M f/L
                                                      (est. 0.012 i (EPA 2006b); converting the 400 f/m3 from the IUR as
                                                              j indicated at left gives 0.012 ug/m3; the Cal/EPA IUR of
                                                              i 0.063 per ug/m3 is 0.000016 for 10'6 risk (2005)
 Benzene (gasoline range organics)
  71-43-2
         IMCL, 0.005 mg/L (1987); IRIS DWUR, 1-10 ug/L for
         |lO'6 risk (2000); IRIS RfD of 0.004 mg/kg-d gives 140 ug/L
         \(2003); DWEL is also 100 ug/L (in the 2006 Edition of the
         jDrinking Water Standards and Health Advisories [EPA 822-
         IR-06-013])
                                                              !IRIS IUR, range 0.13 to 0.45 ug/m3 for 10'6 risk (2000);
                                                              I IRIS RfC is 30 ug/m3 (2003); CREL is 60 ug/m3 (2000);
                                                        0.13   ! draft MRL is 10 ug/m3, from 0.003 ppm (2005); earlier
                                                              | Cal/EPA IUR of 0.000029 per ug/m3 is 0.03 ug/m3 for
 Boric acid
10043-35-3
         |NRC (2000), RfD of 0.3 mg/kg-d, Toxicological Risks of
         i Selected Flame-retardant Chemicals, National Research
         ! Council, http://books.nap.edu/openbook.phpPrecord
 10,500  iid=984l&page=180: IRIS RfD, 0.2 mg/kg-d as B (2004)
         \ (water concentration value would be 40,000, using
         i molecular weight conversion of 61.84 mg boric acid/10.81
         i mg boron, as boric acid)
 Boron trichloride (B in water)
10294-34-5
  7,000
i IRIS RfD, 0.2 mg/kg-d as B (2004), water concentration is
i76,000, using molecular weight conversion of 117.17 mg
i boron trichloride/10.81 mg boron, as B trichloride; DWEL
!is 7 mg/L (2006 Edition of the Drinking Water Standards
land Health Advisories, http://www.epa.gov/waterscience/
icriteria/drinking/dwstandards.pdf)
 Boron trifluoride (F in water)
7637-07-2
         ! IRIS RfD, 0.06 mg/kg-d F (1989), water concentration
         iis 3800, using molecular weight conversion of 67.81 mg
 (2,100)  I boron trifluoride/37.00 mg fluorine, as BF3; Cal/EPA RfD
         iO.04 mg/kg-d for Fluorides gives 1,400 (http://www.arb.
         \ca.epvltoxicslhealthvallcontable.pdf, 2003)
                                                        0.7
                                                                                                                            jHEAST RfC, 0.0007 mg/m3 (1986), http://epa-heast.

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Table 9  Risk-Based Criteria for Additional Industrial Chemicals and Products in Water and Air
Chemical | CASRN
Bromadiolone j 28772-56-7
Cadmium ! 7440-43-9
Carbofuran 1 1563-66-2
Carbon disulfide 1 75-15-0
Chlorine j 7782-50-5
2-Chloroethanol 1 107-07-3
Cyanide salts as sodium salt (NaCN) I 143-33-9
1,2-Dichloroethane i 1r.vnro
/ i i j. i i . j \ '• 107-06-2
(etnylene dicnloride) i
Diesel engine exhaust (mixture) 1 (9-91-1)
1,2-Diisopropyl methylphosphonate i ..
(DIMP) I
1,4-Dithiane (diethylene disulfide) j 505-29-3
Water I Basis
Concn. I (Priority: EPA MCL, then benchmark with most recent
(•/tg/L) \ analysis; others also indicated for context)
\ OPP chronic NOEL, 0.002 mg/kg-d (1998a); with inter/
1 intraspecies factors (100), suggests indicator 0.7
IMCL is 0.005 mg/L (1991), as is the lifetime HA (1987);
| IRIS RfD, 0.0005 mg/kg-d (1994); DWEL is 20 ug/L;
jwater concentration based on MRL would be 7 ug/L, from
i 0.0002 mg/kg-d (1999)
IMCL, 0.04 mg/L (1991); with IRIS RfD, 0.005 mg/kg-d,
jthe water concentration value would be 175 (1987)
3,500 JRfD, 0.1 mg/kg-d (1990)
;MCL, 4 mg/L (1998), same as the lifetime HA; IRIS RfD,
4000 1 0. 1 mg/kg-d (1994); the same RfD is listed in the OPP
ireregistration eligibility document (RED) (EPA 1999)
;No compound-specific toxicity information for this
i compound is available, so assumptions cannot be made
i about toxicity relative to that of another compound.
! IRIS RfD, 0.04 mg/kg-d (1996) (1992 MCL for this CAS
i number as foe CNis 200 ug/L, also the 1987 HA, DWEL
1,400 Ifor free CN is 800 ug/L); intermediate MRL 0.05 mg/kg-d
I would translate to a water concentration value of 1,800 ug/L
| (rounded) (2006)
IMCL (1989); IRIS DWUR, 0.0000026 per ug /L as risk-
I specific concentration for 1 0'6 risk level (1991); archived
5 i PPRTV RfD of .02 mg/kg-d (2002); the intermediate MRL
jof 0.2 mg/kg-d would give a water concentration value of
|7,000 ug/L (2001)
i Values exist for various constituents but not the mixture
|IRIS RfD 0.08 mg/kg-d (1993); DWEL is 3,000; the water
2,800 i concentration value for the MRLof 0.6 mg/kg-d would be
121,000 ug/L (1998); HA, 600 ug/L (1989)
! IRIS RfD, 0.01 mg/kg-d (1993); DWEL is 400 ug/L; HA is
|80ug/L(75>92j
Air | Basis
Concn. I (Priority: EPA benchmark with most recent analysis;
(fig/m?) \ others also indicated for context)

JIRIS IUR, 0.0018 per ug/m3 for 10'6 risk level, for
0.0006 1 concentrations not exceeding 6 \ig/tn?(1992); CREL is
j 0.02 ug/m3 (2000J

JIRIS RfC (1995); CREL is 800 ug/m3 (2001); MRL of 0.3
700 I ppm would give an air concentration value of 930 ug/m3
1(1996)
0.2 ICREL (2000)

| CREL for HCN
9 j
! IRIS IUR, 0.000026 per ug/m3 for 10'6 risk (1991); CREL
1400 ug/m3 (2001); prior Cal/EPA IUR 0.000021 per
0.04 iug/m3is 0.05 ug/m3 at 10'6 (1985); MRL is 0.6 ppm or
1 2,400 ug/m3 (2001)
JIRIS RfC (2003), no CAS; same CREL for CAS shown
5 i (as particulates); Cal/EPA IUR, of 0.003 per ug/m3 is 0.33
| ug/m3 at 10'4 (1998)



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Table 9  Risk-Based Criteria for Additional Industrial Chemicals and Products in Water and Air
Chemical | CASRN
Ethylbenzene (gasoline range organics) 1 100-41-4
Ethylene glycol (from ethylene oxide) \ 107-21-1
Ethylene oxide (Oxirane) j 75-21-8
Fluorine (as P in water, HP in air) \ 7782-41-4
Furan | 110-00-9
Gasoline (in air: as vapors) !
(in water: see representative chemicals) i
n-Hexane (gasoline range organics) j 110-54-3
Kerosene (C9 to C16 hydrocarbons) | 8008-20-6
Mercuric chloride, as mercury j 7487-94-7
Methyl isocyanate j 624-83-9
Oxamyl (Vydate) I 23135-22-0
Paraquat (dichloride form) I 1910-42-5
Water \ Basis
Concn. i (Priority: EPA MCL, then benchmark with most recent
(figlL) \ analysis; others also indicated for context)
IMCL (1992), also the HA (1987); IRIS RfD of 0.1 mg/
700 ikg-d would give a water concentration value of 3,500 ug/L
1(1991); DWEL is 3,000 ug/L
| IRIS RfD, 2 mg/kg-d (1989; also the 1997MRL); DWEL is
1 also 70,000; while HA is 14,000 ug/L (1987)
\ HEAST oral SF of 1 .02 per mg/kg-d (1985)
8 !
|MCL is 4 mg/L as Fluoride (1986); IRIS RfD, 0.06 mg/
;kg-d (1989) using Fluoride data; MRL of 0.05 mg/kg-d for
! Sodium Fluoride would give a water concentration value
' 1 of 1,800 ug/L (2003); the Cal/EPA RfD of 0.04 mg/kg-d
ifor Fluorides would give a water concentration value of
1 1,400 ug/L (2003)
35 jIRISRfD, 0.001 mg/kg-d (1989)
i See 5 example constituents: BTEX and n-hexane
| HEAST RfD of 0.06 mg/kg-d (1989); the provisional RfD
	 ifrom EPA is also 0.06 mg/kg-d (www.epa.gov/ttn/hlthef/
ihexane.html): HA of 4000 ug/L (1987) (only as a 10-dHA,
ifor a 10-kg child, IL/d)
i Values exist for various constituents but not the mixture
1 IRIS RfD, 0.0003 mg/kg-d (1995); int. MRL 0.002 mg/
ikg-d would yield a water concentration value of 70 ug/L
! (1999); DWEL of 1 0 ug/L for Hg; MCL of 2 ug/L for Hg
| (inorganic) (1992; also 1987 HA)
i Forms methylamine, CO2, others; no public benchmark
1 MCL (1994); HA of 1 0 ug/L, child, 1 d and 1 0 d (2005);
IIRIS RfD 0.025 mg/kg-d would yield a water concentration
200 lvalue of 880 ug/L (1991); DWEL is 35 ug/L; of 0.001 mg/
jkg-d gives a water concentration value of 35 ug/L OPPTS
Ichronic RfD (EPA 2000d)
1 IRIS RfD, 0.0045 mg/kg-d (1991); DWEL is 200
Air | Basis
Concn. j (Priority: EPA benchmark with most recent analysis;
(figlm?) \ others also indicated for context)
JIRIS RfC (1991); CREL is 2,000 ug/m3; int. MRL is
1,000 14,300 (1999)
400 | CREL (2000
j CREL (2001); intermediate MRL of 0.09 ppm is 1 60 ug/
30 1 m3 (1990); earlier Cal/EPA IUR of 0.000088 per ug/m3 is
1 1.1 ug/m3 at 10'4 risk (1987)
\ CREL for HF is 14 ug/m3, 1 3 ug/m3 as F' (2003)
(14)

i CREL (1991); Wl-suggested 6 ppm for homes (per work
2,100 i level) (Wisconsin Department of Health and Family Services
\[WIDHFS] 2004) or 18,000-27,000 ug/m3
JIRIS RfC (2005); MRL of 0.6 ppm is 2,100 ug/m3 (1999);
70Q | CREL 7,000 (2005)
1 0 j MRL, intermediate (for 1 5-364 d of exposure) (1995)
i CREL, for inorganic Hg (2000); intermediate MRL for
Q og \ mercury is 0.2 ug/m3 (1999)
1 | CREL (2005;

i OPPTS (1997c) indicates short-term inhalation NOEL
10.01 ug/L; UF 1,000 suggests indicator of 0.01 ug/m3

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Table 9   Risk-Based Criteria  for  Additional Industrial  Chemicals and Products in Water and Air
Chemical CAS RN
Phenol 108-95-2
Polychlorinated biphenyls (PCBs) 1336-36-3
Propylene oxide 75-56-9
Sodium fluoroacetate (the example salt) 62-74-8
Sulfur dioxide 7446-09-5

Toluene (gasoline range organics) 1 08-88-3
Xylenes (gasoline range organics) 1 330-20-7
Water \ Basis
Concn. ! (Priority: EPA MCL, then benchmark with most recent
(ftg/L) I analysis; others also indicated for context)
;IRIS RfD, 0.3 mg/kg-d (2002); this is also the DWEL; the
' I draft HA is 2,000 ug/L (1992)
JMCL (1992); IRIS DWURof 0.1 ug/L, 10'6risk, if
!<1,000 ug/L (1997); water concentration value for MRL is
0.5 J0.7 ug/L, from 0.02 ug/kg-d Aroclor 1254 (2000); Cal/EPA
i RfD of 0.02 ug/kg-d would give a water concentration value
;of 0.7 ug/L (1996)
JIRIS DWUR, 10'6 risk (1994), IRIS oral SF is 0.24 per mg/
0.1 |kg-d; OPPTS RfD of 0.001 mg/kg-d would give a water
iconcentration value of 35 ug/L (see EPA 2005c)
0.7 | IRIS RfD, 0.00002 mg/kg-d (1993), same for OPP (1995)
|EPA (2006b) health-based value, 2006 Edition of the
! Drinking Water Standards and Health Advisories table,
ihttp://www.epa.gov/waterscience/criteria/drinking/
idwstandards.pdf (For SO, that would form in water)

!MCL(1992); IRIS RfD of 0.08 mg/kg-d (2005); DWEL is
' |3000 ug/L
|MCL (1992); IRIS RfD, 0.2 mg/kg-d (2003); DWEL
1 0,000 I (7,000 ug/L); the draft MRL, 0.6 mg/kg-d, would yield a
1 water concentration value of 21,000 ug/L (2005)
Air | Basis
Concn. ! (Priority: EPA benchmark with most recent analysis;
(fig/m?) \ others also indicated for context)
20Q JCREL (2000)
I IRIS ILIR-based level for 1 0'6 risk, when < 1 00 ug/m3
i (1997); OREL 1 .2 ug/m3, while Cal/EPA IUR of 0.00057
0.01 ;per ug/m3 is 0.0018 ug/m3 for 10'6 risk (1991)
ilRIS IUR, (1994); IRIS RFC of 30 ug/m3 (1990); OREL of
0.3 1 30 ug/m3 (2000); prior Cal/EPA IUR is 3.7E-6, 27 ug/m3
1 for 10'6 risk (1999)

iNAAQS, 0.03 ppm (1990, an. av); OREL 660 (1992)
79 |

I IRIS RfC (2005); MRL 0.08 ppm (2000) is the OREL,
' i 300 ug/m3 (2000)
! IRIS RfC (2003); MRL 0.05 ppm is 650 ug/m3 (2005);
100 i the OREL is 700 ug/m3 (2000)
    aThis table identifies risk-based chronic exposure criteria in water and air for industrial contaminants, including four mixtures and several fate products. A number of NHSRC list chemicals are fate products of others addressed in
other tables within this document, so those are not repeated here (see Table 2 note). Fate products of chemicals are italicized in this list, with parents in parentheses. Chemicals only from the SAM report (not on the NHSRC list or their
fate products) are in lighter font (blue). More than half (23) have values for both air and water. Note for sulfur dioxide in air, an. av represents annual average.

    The toxicity value dates indicate when the value was established, reassessed, or updated. The EPA sources include:  IRIS (accessed 2007), MCL list (2006 table), drinking water advisories including HAs (2006 tables), NAAQS (2005
list, from 1990 and updates), and OPPTS (which includes various studies from the OPP, and Office of Pollution Prevention and Toxics, OPPT); non-EPA sources include: ATSDR:  MRLs (2006 list); NZ maximum residue limit
(MResL) Food Standards Australia New Zealand (FSANZ); and states, including Cal/EPA: CREL, AREL, IUR, RfD (2005a, b, c, d); and Wisconsin and Michigan limits for air and water (WIDHFS 2004, MDCH 2006).

    Concentrations from a UR or SF correspond to a risk of 10'6. Calculated values are rounded to 2 significant figures (e.g., for mercuric chloride and paraquat in water, and SO2 in air). Note for ATSDR MRLs, intmd = intermediate
(benchmarks for shorter durations such as intermediate MRLs that cover exposures of 15—364 days can be useful, considering discrete releases to dynamic systems, especially for nonpersistent chemicals). Parentheses are used to identify
values that are (1) from draft benchmarks; (2) derived from related benchmarks, including for fate products or surrogates; and (3) from benchmarks for shorter durations, when no applicable chronic limits were found—such as the
intermediate MRLs and the 10-d child HA for n-hexane.
    For water values, the MCL is the priority source while IRIS is the primary source for air values. Where multiple benchmarks exist, others are also shown to offer further context for framing the method validation (for example, if a
release occurred in California, Cal/EPA values would also likely be addressed). Values reflecting the most recent evaluation are preferred, and final values are preferred over drafts or those under review. As an example, although the EPA HA
for boron (600 ug/L) is less than one-tenth the concentration calculated from the IRIS RfD, that RfD is from 2004 while the HA is from a 1992 draft document that is under review. When a non-EPA benchmark is lower than an EPA
value, those other values are indicated in lighter font (green). For example, the concentration identified as both the MRL and Cal/EPA CREL for toluene (300 ug/m3) is about 17 times lower than the EPA RfC, but they were established
in 2000 while the RfC is from 2005.
    For aldicarb and its sulfoxide and sulfone, the 1995 health advisories (given in EPA 2006) indicate that the combined concentration should not exceed 7 ug/L, but the MCLs reflected in that statement (3, 4, and 2 ug/L, respectively)

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          have been stayed. For ammonia, no health-based benchmark was found. The EPA (2005c) considers the taste threshold of about 35,000 ug/L a conservative (low) surrogate for a health-based level because it is below the NOAEL.

              For asbestos, the 1993 IRIS IUR is based on phase contrast microscopy (PCM) counts for fibrous material, not asbestos-specific; the correlation between PCM data and specific fiber (f) count or mass measurements by transmission
          electron micrsoscopy (TEM) is described as very poor. Although a conversion factor of 30 ug/m3 per f/mL was adopted (same as Cal/EPA conversion of 100 PCM f/0.003 ug, 0.00003 ug/f), IRIS acknowledges this is highly uncertain
          (www.epa.gov/iris/substy0371.htm); the Cal/EPA (2005d) IUR is 0.063 per ug/m3, and the potency factor is 220 per mg/kg-d.
              For boron trichloride in water, the toxicity of boric acid as boron (CAS 7440-42-8) is limiting. In contrast, for boron trifluoride in water the fluoride is limiting. Analytical methods for water are often based on boron equivalents, so
          that is the main concentration provided; molecular-weight-scaled concentrations are also provided for the full compound (molecular weight for boron is 11). Note that the earlier OPP RED report indicated an  RfD of 0.09 mg/kg-d,
          which would be 3,200 ug/L (EPA 1994).
              For bromadiolone, the indicator of 0.7 ug/L is derived from the OPP chronic level. For comparison, the New Zealand MResL is 0.001 mg/kg (noted as being set at or about the analytical quantification limit). As a crop rodenticide,
          considering the mean per capita U.S. intakes of vegetables (4.3), fruit (3.4), and grain (4.1), which total 11.8 g/kg-d (EPA 1997a): if the residue were at its limit, a 70-kg adult would take in 0.8 ug/d; if that amount were taken in from
          2 L water instead, the equivalent concentration would be 0.4 ug/L.
              Cyanide salts are conservatively represented by sodium cyanide because it is most toxic (its IRIS RfD is lowest); the range across various salts extends to 1,000 ug/L, as molecular-weight-scaled from the CN value. Note that
          the molecular weight ratio of NaCN/CN is 49/26 (1.9) and the NaCN RfD is double that for CN and HCN, 0.02 mg/kg-d, which correspond to 700 ug/L. The 1987 HA for cyanide is 0.2 mg/L (listed with the sodium cyanide
          CAS number). (Note that the current MCL from 1992 for free cyanide is 0.2 mg/L or 200 ug/L; for context, typically only about 10% of HCN in water is as free cyanide.)

              Diesel exhaust constituents include polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides, and particulates, such as carbon black. For gasoline range organics, automotive gasoline contains up to 150 chemicals, including the five
          listed above (ATSDR 1995): benzene (comprising 2%), toluene, ethylbenzene, and xylenes (BTEX), and n-hexane. The odor threshold is 0.25 ppm, and a state-recommended limit for air in homes is 6 ppm (WIDHFS 2000); with a
          conversion of 3-4.5 mg/m3 (see Table A2 notes), that is 18,000-27,000 ug/m3.

              For propylene oxide, the OPP chronic oral RfD of 0.001 mg/kg-d could indicate 35 ug/L, depending on bioavailability (EPA 2005c).
              Non-EPA sources include: New Zealand Food Authority (ETO and 2-chloroethanol in water), State of Michigan (H2S in water), ATSDR (ammonia, ETO, kerosene, mercury in air), and Cal/EPA (chlorine, ethylene oxide, fluorine,
          HF, methyl isocyanate, and phenol). Applicable chronic public benchmarks were not found for 21 chemicals from NHSRC and SAM (see Table 12 footnote).
Ul

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                               Information for radionuclides is provided in:
                               • Table 10 — Nuclear Decay Data for Primary Radionuclides and Potentially
                                   Important Radioactive Progeny (Set 4)
                               • Table 11 — Risk-Based Criteria for Primary Radionuclides in Water and Air (Set 4)
                               The persistence of radionuclides in water and air is determined by environmental
                           processes and by the rate of physical decay of the radionuclides to stable elements or to
                           other radionuclides. The decaying radionuclide is referred to as the parent radionuclide.
                           A radionuclide that arises from physical decay of a parent radionuclide is referred to as
                           a daughter radionuclide or radioactive progeny A parent radionuclide together with a
                           series of radioactive progeny originating with the parent is referred to as a decay chain.
                               The rate of physical decay of a radionuclide is described by its half-life, which is the
                           length of time for a given amount of a radionuclide to decrease to half that amount. The
                           amount of a radionuclide present in a given volume of material is typically measured
                           in terms of activity, defined as the number of physical decays of the radionuclide per
                           unit time. The International System of Units (SI) unit of activity is the becquerel (Bq),
                           defined as one disintegration per second. In this report, activity is given in conventional
                           units  of curie (Ci) or picocurie (pCi) because these units are still commonly used in the
                           US. SI and conventional units for activity are related as follows: 1 Ci - 3-7 x 1010 Bq, 1
                           pCi = 10'12 Ci, and 1 Bq - 27 pCi.
                               Basic nuclear decay data for the 15 primary radionuclides addressed in this report
                           and their potentially important  radioactive progeny are summarized in Table 10. The
                           listed data include half-lives, decay modes, and energies of different types of radiation
                           emissions. Radiation energies listed for a radionuclide include its total alpha energy
                           (if any), the prominent alpha energy and its yield (i.e., the percentage of decays of the
                           radionuclide giving rise to the prominent alpha energy), the total photon energy (if any),
                           the prominent photon energy and its yield, and the total energy of electron  emissions.
                           The total energy of electron emissions represents the sum of the continuous electron
                           spectrum  (beta spectrum) and discrete mono-energetic electrons.
                               The specific activity (activity per unit mass)  of each of the 15 primary radionuclides
                           is listed in Table 11 in units of curies per gram (Ci/g). These specific activities were used
                           to convert risk-based activity criteria (columns 3 and 5 of Table 11) to risk-based mass
                           criteria (columns 4 and 6, respectively). As discussed below, the specific activity indicated
                           for uranium-238 represents a mixture of uranium-238, uranium-235 and uranium-234.
                               Risk-based activity criteria for water and air were based on risk coefficients
                           given in Federal Guidance Report No. 13 (FGR 13), "Cancer Risk Coefficients for
                           Environmental Exposure to Radionuclides" (EPA 1999). A risk coefficient for ingestion
                           or inhalation of a radionuclide is an estimate of the probability of radiogenic cancer
                           mortality  (or morbidity) per unit activity (Bq"1) of that radionuclide taken into the body.
                           The risk coefficients in FGR13 were derived for a hypothetical stationary population
                           whose demographics,  cancer rates, and age- and gender-specific usage of environmental
                           media other than air were based on data for the U.S. population circa 1990 (Ershow
                           and Cantor 1989; NCHS 1992, 1993a, 1993b, 1997; McDowell et al. 1994). Age- and
                           gender-specific air intake rates were based on reference values recommended by the
                           International Commission on Radiological Protection (ICRP 1994).
                               For each of the 15 primary radionuclides addressed in the present report, separate
                           risk coefficients for inhalation are provided in FGR 13 for different "absorption types"
                           as defined by the ICRP (1994). An absorption type for a radionuclide carried in air as a
46

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particulate aerosol represents a specified level of solubility of the aerosol in the respiratory
tract and an associated rate of absorption of the carried radionuclide to blood. The following
absorption types are defined in ICRP Publication 66 (1994) and addressed in FGR 13:
    •   Type F, representing fast dissolution and a high level of absorption to blood;
    •   Type M, representing a moderate rate of dissolution and an intermediate level of
        absorption to blood; and
    •   Type S, representing slow dissolution and a low level of absorption to blood.

    In many cases a default absorption type and hence a default risk coefficient for
inhalation of a given  radionuclide is indicated in FGR 13 for use when no information is
available on the physical or chemical form of the inhaled material. The default type for a
radionuclide is based on recommendations given in ICRP Publication 72 (ICRP, 1996),
which reflect available information on the solubility of commonly encountered forms of
the radionuclide. In the present report, the risk-based criterion for a radionuclide in air
is based on its default risk coefficient if a default value is indicated in FGR 13- In each of
the remaining cases (identified in footnote d  to Table  11), the risk-based criterion for air is
based on the maximum of the risk coefficients for inhalation of Type F, Type M, and Type S
material.
    Separate risk coefficients are provided in FGR 13 for ingestion of inorganic and organic
forms of polonium-210 in tap water. The risk coefficient for inorganic polonium-210 was
used to  derive a risk-based criterion for polonium-210 in water because this is presumed to
be the more likely form of this radionuclide in drinking water.
    Use of a risk coefficient to derive a risk-based criterion for a radionuclide requires a
reference risk, i.e., a limiting value for the projected cancer mortality risk resulting from
intake of the radionuclide in water or air. For the purpose of deriving Risk-Based Criteria
for radionuclides in water and air, a reference risk was chosen for consistency with excess
cancer mortality risks implied by current EPA standards for radionuclides in water or air.
Current standards for drinking water (EPA 2006) include a concentration limit of 15
pCi L"1  for alpha emitters,  an annual dose limit for beta and photon emitters of 4 mrem
to the total body or any organ, a concentration limit of 5 pCi L"1 for radium-226 and
radium-228 combined, a concentration limit of 8 pCi L"1 for Sr-90, and a concentration
limit of 30 ug L"1 for uranium. EPA National Emission Standards for Hazardous Air
Pollutants (NESHAPs) specify an annual dose limit of 10 mrem effective dose equivalent
for any  member of the public from emissions of radionuclides  to the ambient air (EPA
1991, 2004). These standards for water and air were developed over a period of decades
for regulatory purposes and represent a range of projected risks when converted to cancer
mortality risks on the basis of FGR 13- The implied excess cancer mortality risks are
centered at about 10"6 y"1 and  for most radionuclides,  fall in the range 10"7 y"1 - 10"5
y"1, where "y"1" refers  to intake over a one-year period. For example, for the 15 primary
radionuclides addressed in the present report, these standards correspond to projected
excess cancer mortality risks ranging from 3x10"7 y"1 to 7x10"6 y"1 with a median value of
about 10-6 y"1. Thus, the value 10"6 y"1 appears to be a representative value for excess cancer
mortality risks implied by current EPA standards for water and air. This value was used as
the reference risk for  the purpose of deriving  Risk-Based Criteria for radionuclides. That is,
the risk-based criterion for a radionuclide in water or air is the  activity concentration,  or the
equivalent mass concentration, projected to result in an excess  cancer mortality risk of 10"6
due to intake over a one-year period.
                                                                                                          47

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                               Risk-Based Criteria for water are based on intake of 2 L d"1, a value commonly used
                           by EPA in development of guidance concerning consumption of water (EPA 1996,
                           EPA 2000). Risk-Based Criteria for air are based on intake of 17-8 m3 d"1, which is the
                           population-averaged air intake rate estimated in FGR 13-
                               Risk-Based Criteria for uranium-238 were based on the assumption that uranium
                           238 is accompanied by uranium-234 and uranium-235 in water and air. For any
                           mixture of these three uranium isotopes, the derived risk-based activity criterion
                           for water is in the range 30-33 pCi L"1, and the derived risk-based activity criterion
                           for air is in the range 0.014-0.017 pCi m"3. The weak dependence of the risk-based
                           activity criteria on the isotopic ratio results from the fact that the risk coefficients for
                           uranium-238, uranium-235, and uranium-234, which are given in FGR 13 as risk
                           per unit activity taken into the body, differ little from one another for a given mode of
                           intake. On the other hand, the risk-based mass criterion of uranium-238 in water or
                           air depends strongly on the relative activities of these three uranium isotopes because
                           the three isotopes have considerably different specific activities. The specific activity of
                           uranium-234 is almost 20,000 times that of uranium-238 and almost 3000 times that
                           of uranium-235. The risk-based mass criterion is a particularly important consideration
                           for uranium because uranium presents a chemical hazard (nephrotoxicity) as well as a
                           radiological hazard, and the chemical hazard generally is measured in terms of the mass
                           of uranium taken into the body or the mass that accumulates in the kidneys.
                               The specific activity of a mixture of uranium-238, uranium-235, and uranium-234
                           is at least 0.34 pCi ug"1 (the specific activity of uranium-238) and may be higher by an
                           order of magnitude or more for uranium enriched in uranium-235. The specific activity
                           of natural uranium, which is approximately 99-27% uranium-238, 0.72% uranium-235,
                           and 0.0057% uranium-234 by mass, is 0.67 pCi ug"1.  The specific activity of uranium
                           in drinking water generally is higher than that of natural uranium due to an elevated
                           concentration of uranium-234 in drinking water relative to natural uranium (Karpas
                           et al. 2005). Typical values for the specific activity of uranium  in drinking water in the
                           range 0.8-1.3 pCi ug"1 have been estimated from isotopic compositions of uranium
                           found in public water systems (Federal Register 56, July 18,  1991; Wong et al. 1999;
                           EPA 2007b). In the present report, a rounded central estimate of 1 pCi ug"1 is used as
                           the specific activity of uranium in drinking water and for consistency is also applied to
                           air. Risk coefficients for uranium-234, which are slightly higher than those for uranium
                           238 and uranium-235, are applied in the derivations of risk-based activity criteria for
                           uranium-238 in water or air. The resulting risk-based activity criterion and risk-based
                           mass criterion for uranium-238 in water are 30 pCi L"1 and 30 ug L"1, respectively. These
                           values are consistent with the current EPA standard for uranium in drinking water, as
                           summarized in the following EPA Memorandum (EPA 2007b):
                                   "The 2000 MCL  [Maximum Contaminant Level] rule established an MCL
                               for uranium of 30 micrograms per liter (ug/L). For the MCL rulemaking, EPA
                               assumed a typical conversion factor of 0.9 pCi/ug for the mix of uranium isotopes
                               found at public water systems, which means that an MCL of 30 ug/L will typically
                               correspond to 27 pCi/L. EPA considered the 30 ug/L level (which corresponds to
                               a 27 pCi/L level) to be appropriate since it is protective for both kidney toxicity
                               and cancer. However, the relationship between mass concentration (ug/L) and
                               activity (pCi/L) is dependent upon the relative mix of the radioactive isotopes
                               (e.g., uranium-234, uranium-235, uranium-238)  that comprise the uranium at
48

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    a particular drinking water source. In circumstances with more extreme conversion
    factors (> 1.5 pCi/ug), uranium activity levels may exceed 40 pCi/L. In these
    circumstances, EPA recommends in the 2000 MCL rule that drinking water systems
    mitigate uranium levels to 30 pCi/L or less, to provide greater assurance that adequate
    protection from cancer health effects is being afforded.

    The derived risk-based activity criterion for uranium-238 in air, 0.014 pCi m~3, was
based on the risk coefficient for inhalation of a moderately soluble form of uranium-234
(Type M) because this is the default absorption type identified in FGR 13 for uranium
isotopes. The corresponding risk-based mass criterion is 0.014 ug m~3. Based on the
biokinetic model for uranium applied in FGR 13, the projected kidney concentration
from long-term exposure to this concentration of uranium in air would remain below
0.001 ug g"1, regardless of the inhaled form of uranium. Renal effects of uranium have not
been observed below estimated kidney concentrations of a few tenths of a microgram
per gram.
    As explained below, the Risk-Based Criteria for the primary radionuclides other than
uranium-238 were derived under the assumption that there is no intake of accompanying
radioactive progeny. However, each of the risk coefficients used to derive the risk-based
criteria in Table 11 reflects the contribution of potentially significant radioactive progeny
(those listed in Table 10) produced in  the body after intake of the parent radionuclide. The
contributions of the radioactive progeny to these risk coefficients are particularly important
for four of the primary radionuclides:  cesium-137, ruthenium-106, radium-226, and
strontium-90.
    Four of the 15 primary radionuclides, cobalt-60, europium-154, iridium-192, and
polonium-210, have no radioactive progeny. No  radioactive progeny are listed in Table
10 for five other primary radionuclides, americium-24l, californium-252, curium-244,
plutonium-238, and plutonium-239,  because the progeny grow in only slowly and would
present little risk compared with the parent over the first century after release of the parent
into the environment.
    Relative activities of members of the radium-226 chain in water or air are difficult to
predict due to the high mobility of the first daughter in the decay chain, the inert gas radon-
222. The derived Risk-Based Criteria for radium-226 listed in Table 11 would change little
if it were assumed that radium-226 is in equilibrium with its relatively short-lived daughters,
meaning the decay chain members down to, but not including, lead-210. The presence of
significant activities of lead-210 and subsequent members of the chain relative to the activity
of radium-226 over an extended exposure period seems unlikely. Lead-210 would grow in
only slowly and would not be  expected to remain with the higher chain members in air or
water for an extended period even if the radium-226 decay chain were in equilibrium when
the original release occurred.
    Each of the primary radionuclides cesium-137, ruthenium-103, ruthenium-106,
and strontium-90 gives rise to a short-lived daughter that quickly comes into equilibrium
with the parent and is expected to have an activity concentration similar to that of the
parent radionuclide in water or air. For each of these four primary radionuclides, however,
intake of the daughter in water or air can be neglected because the projected tissue doses
and cancer risk are negligible compared with the  projected doses and risk from intake of
the parent. This is illustrated by intake of ruthenium-106 and its daughter rhodium-106
in drinking water. As indicated in Table 10, the radiological half-life of ruthenium-106 is
                                                                                                        49

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                          about 1 year, the radiological half-life of rhodium-106 is about 30 seconds, and decay
                          of a rhodium-106 atom results in considerably greater release of energy than decay
                          of a ruthenium-106 atom. Decay of a ruthenium-106 atom gives rise to an atom of
                          rhodium-106, which soon decays due to the short half-life of rhodium-106. This means
                          that these two radionuclides quickly come into equilibrium, that is, their activities
                          (decays per unit time) are expected to be about the same in drinking water, although the
                          number of ruthenium-106 atoms would remain about six orders of magnitude higher
                          than the number of rhodium-106 atoms due to the difference in half-lives. Intake of
                          drinking water would result in intake of about one million atoms of ruthenium-106 for
                          each atom of rhodium-106 taken into the body, so that the dose and risk from intake of
                          rhodium-106 would be trivial compared with that from intake of ruthenium-106 despite
                          the much higher energy per decay represented by rhodium-106.
                             Some of the radioactive progeny that represent little additional dose or risk due to
                          their intake in water or air may represent important or even dominant sources of dose
                          and risk after intake of the parent due to production and decay of the progeny in the
                          human body. As  an illustration, again consider the parent-daughter pair ruthenium-106
                          and its daughter  rhodium-106. Each decay of ruthenium-106 in the body gives rise to  a
                          rhodium-106 atom that quickly decays and deposits considerably more energy in body
                          tissues than was deposited by the preceding decay of ruthenium-106. Due to the much
                          higher energy associated with rhodium-106 decay than with ruthenium-106 decay,
                          rhodium-106 produced in the  body is estimated to represent more than 99% of the dose
                          and risk resulting from intake of ruthenium-106. Thus, although intake of rhodium-106
                          accompanying ruthenium-106 in drinking water or air is unimportant compared with
                          intake of ruthenium-106, the production and decay of rhodium-106 in the body is by
                          far the dominant source of risk from ingested or inhaled ruthenium-106.
Table 10 Nuclear Decay Data3 for Primary Radionuclides and  Potentially
           Important Radioactive Progeny

Radionuclidec
Americium-24 1
Californium-252
Cesium-137
Barium-12i7ni
Cobalt-60
Curium-244
Europium-154
Iridium-192
Plutonium-238
Plutonium-239
Polonium-210
Half-life
432 y
2.65 y
30.2 y
2.55m
5.27 y
18.1 y
8.59 y
73.8 d
87.7 y
24,000 y
138.4d
Decay
modeb
a
aSF
P-
IT
P-
a SF
P-EC
(3-EC
aSF
a
a
Total
alpha
5.48
5.92
-
-
-
5.79
-
-
5.49
5.15
5.3
Energy (MeVper nuclear transformation)
Prominent alpha
Yield
(%)
84.7
81.5
-
-
-
76.4
-
-
70.9
70.7
100
Energy
5.49
6.12
-
-
-
5.8
-
-
5.5
5.16
5.3
Total
photon
0.029
<0.01
<0.01
0.596
2.504
<0.01
1.249
0.816
<0.01
<0.01
<0.01
Prominent photon
Yield
(%)
35.9
2.32
<0.01
89.74
99.98
3.19
40.56
82.71
3.94
1.6
<0.01
Energy
0.06
0.02
0.283
0.662
1.332
0.018
0.123
0.317
0.017
0.014
0.803
Total
electron11
0.037
0.006
0.188
0.065
0.097
0.008
0.273
0.218
0.011
0.007
<0.001
50

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Radionuclidec
Radium-226
Radon-222
Polanium-218
Lead-214
Astatine-218
Bismuth-214
Polanium-214
Thallium-210
Lead-210
Bismuth-210
Polonium-210
Mercury-206
ThaU.ium-206
Ruthenium-1 03
PJ}odium-103m
Ruthenium-1 06
Rhodium-106
Strontium-90
Yttrium-90
Uranium-238
Thorium-234
Protactinium-234m
Protactinium-234
Uranium-234
Thorium-230
Radium-226'
Half-life
1600y
3.82 d
3.10m
26.8m
1.5s
19.9m
0.00016s
1.3m
22.2y
5.0d
138.4 d
8.15m
4.2m
39.3d
56.1 m
373.6 d
29.8s
28.8 y
64. Ih
4.5xl09y
24. Id
1.17m
6.7 Oh
250,000 y
75,000 y
1600y
Decay
modeb
a
a
a p-
P-
a p-
13- a
a
P-
/3-a
ft- a
a
P-
P-
P-
IT
P-
P-
P-
P-
aSF
P-
P-IT
ft-
a
a
a
Total
alpha
4.77
5.49
6
-
6.68
<0.1
7.69
-
<0.1
<0.1
5.3
-
-
-
-
-
-
-
-
4.19
-
-
-
4.76
4.67
4.77
Energy (MeVper nuclear transformation)
Prominent alpha
Yield
(%)
94.4
99.9
100
-
89.9
0
100
-
<0.01
<0.01
100
-
-
-
-
-
-
-
-
79
-
-
-
71.4
76.4
94.4
Energy
4.78
5.49
6
-
6.69
5.45
7.69
-
3.72
4.64
5.3
-
-
-
-
-
-
-
-
4.2
-
-
-
4.78
4.69
4.78
Total
photon
<0.01
<0.01
-
0.253
-
1.479
<0.01
2.763
<0.01
<0.01
<0.01
0.122
<0.01
0.496
<0.01
-
0.206
-
<0.01
<0.01
0.011
0.016
1.472
<0.01
<0.01
<0.01
Prominent photon
Yield
(%)
3.59
0.08
-
37.6
-
46.1
0.01
98.96
10.11
<0.01
<0.01
31
0.04
91
4.02
-
20.4
-
<0.01
3.04
4.84
0.84
33.41
4.18
3.32
3.59
Energy
0.186
0.51
-
0.352
-
0.609
0.8
0.8
0.011
0.304
0.803
0.305
0.075
0.497
0.02
-
0.512
-
0.016
0.016
0.063
1.001
0.014
0.016
0.015
0.186
Total
electron11
0.004
< 0.007
<0.001
0.295
0.001
0.663
< 0.001
1.27
0.04
0.389
< 0.001
0.421
0.54
0.066
0.038
0.01
1.411
0.196
0.933
0.009
0.062
0.817
0.404
0.014
0.015
0.004
y = year, d = day m = minute, s = seconds, MeV = million electron volts
aData from compilation by Endo et al. (2005).

b a= alpha emission, (3- = beta-negative emission, SF = spontaneous fission (nuclear fission occurring without the striking of the atom by a neutron or other
 particle), IT = isomeric transition (process in which energy is released by emission of a photon, resulting in an atom with the same mass number and atomic
 number but with a more stable configuration), EC = electron capture (process in which an electron in an atoms inner shell is drawn into the nucleus and
 combines with a proton, forming a neutron and a neutrino; the neutrino is ejected from the atoms nucleus).
Italicized radionuclides following a primary radionuclide are its decay chain members (radioactive progeny). Cobalt-60, europium-154, iridium-192, and
 polonium-210 have no radioactive progeny.  Radioactive progeny of americium-24l, californium 252, curium-244, plutonium-238, and plutonium-239 are
 not listed because their activity is insignificant compared with that of the parent for  decades after entry of the parent into the environment or the human body.
dContinuous electron spectrum (beta spectrum) plus discrete mono-energetic electrons.

"Uranium-238 chain continues with radium-226 progeny shown earlier in table.
                                                                                                                                          51

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Table 11   Risk-Based Criteria for  Primary Radionuclides in Water and Air
Radionuclide
Americium-24 1
Californium-2526''
Cesium- 137
Cobalt-60
Curium-244
Europium- 154d
[ridium-192d
Plutonium-238
Plutonium-239
Polonium-210
Radium-226
R.uthenium-1 03
R.uthenium-1 06
Strontium-90
Uranium-238e
Specific
Activity
(dig)
3.4
540
86
1,100
81
270
9,200
17
0.062
4,500
1.0
32,000
3,300
140
10'6
Water1
(pCi/L) (jtg/L)
18 5.3 x 10'6
16 3.0 x 10'8
65 7.6 x 10'7
130 1.2 xlO7
23 2.8 x 107
230 8.5 x lO7
330 3.6 x 10'8
13 7.6 x 10'7
13 2.1 x 10'4
5.0 1.1 xlO's
5.2 5.2 xlO6
630 2.0 x la8
57 1.7 xlO8
28 2.0 x 10'7
30 30
Aii*
(pCilnf) fygln?)
0.0063 1.9xlO'9
0.0036 6.7 xlO'12
19 2.2 xlO'7
5.2 4.7x10-'
0.0068 8.4 x 10-"
0.89 3.3 x 10-'
7.2 7.8 x lO'10
0.0052 3.1 x lO'10
0.0052 8.4 x lO'8
0.015 3.3 xlO'12
0.014 1.4 xlO-8
20 6.3 x lO'10
1.7 5.2 xlO-10
1.6 1.1 x lO'8
0.014 1.4 xlO'2
   'Based on a reference risk of 10^ y1 and water intake of 2 L d'1.

   bBased on a reference risk of 10's y1 and air intake of 17.8 m3 d'1.

   GCalifornium-252 is not addressed in FGR 13 (EPA 1999). Risk coefficients for californium-252 for use in the present report were derived using the methods
    of FGR 13 and the current biokinetic and dosimetric models of the ICRP as summarized in ICRP Publication 72 (ICRP 1996). The derived risk coefficients
    for ingestion and inhalation are 2.30  X 10'9 Bq'1 (8.52 X 10'11 pCi'1) and 1.15 X 10's Bq'1 (4.26 X 10'8 pCi'1), respectively.

   dNo default absorption type for this radionuclide is identified in FGR 13 (EPA 1999) or ICRP Publication 72 (1996). The risk-based criterion for air is based
    on the maximum of the risk coefficients for inhalation of Type F, Type M, and Type S material.

   ^The specific activity of uranium-238 is 3.4 X 10'7 Ci/g. It was assumed in the derivation of risk-based chronic exposure criteria for uranium-238 in water
    and air that uranium-238 is accompanied by uranium-235 and uranium-234. The specific activity of the mixture of the three uranium isotopes is assumed
    to be 10's Ci/g (1 pCi/ug). The risk-based chronic exposure criteria listed for uranium-238 are intended for application to any mixture of uranium-238,
    uranium-235, and uranium-234.
52

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            Summary  and  Discussion
Water and air were reviewed for more than approximately 100 contaminants identified in
the NHSRC list and SAM report combined. Chronic public benchmarks were emphasized,
to support validation of analytical methods. These evaluations were phased, beginning with
the set of 23 chemicals identified as validation priorities. Companion fate analyses were
conducted to identify associated products expected to form in air and water over different
intervals. Benchmarks were then further reviewed for those products.
    After completing the evaluation for the initial priority set, this benchmark assessment
was extended to the entire NHSRC list and SAM report to pursue full coverage for method
validation. In concert, physical-chemical fates were analyzed for all the industrial chemicals
and agents, and physical fate was assessed for the radionuclides. Benchmarks were then
reviewed for these further sets and also for the biological contaminants. Following thousands
of checks to assess hundreds of contaminants and fate products combined across a dozen
benchmarks, more than 200 distinct risk-based criteria were identified as validation targets.
These concentrations are summarized in Table 12. The majority are from EPA benchmarks,
with most based on environmental exposures that are assumed to continue for decades.
Where multiple relevant benchmarks exist, EPA values are prioritized; the emphasis is on
values that reflect most recent evaluations.

5.1  Fate  Products
Fate analyses provide essential input to method validation; some of these associated
chemicals can accompany the primary contaminants when released (e.g., chemical
agents), depending on the synthesis and release methods. This fate overview emphasizes
key products. It is noted that the yields, stability and toxicity of numerous agent fate
compounds indicate that many are of little to no significant health concern, especially when
compared to characteristics of the parent  compound (Talmage et al 2007).
                                                                                                   53

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Table 12  Summary of Risk-Based Criteria as Analytical Method Validation Targets for Water and Air
Contaminant
CASRN
Concn.
in Water
(mIL)
Concn.
in Air
(ftglrr?)
Chemicals
Acetone
Aldicarb (Temik)
Aldicarb sulfone
Aldicarb sulfoxide
Allyl alcohol
Ammonia, anhydrous ammonia
Arsenic, inorganic (including trivalent)
Arsine (agent SA, arsenic hydride)
Asbestos (can exist in various forms)
Benzene (gasoline range organics)
Boric acid (as B equivalents in water)
Boron trichloride (as If in water)
Boron trifluoride (as P1 in water)
Bromadiolone
Cadmium
Carbofuran
Carbon disulfide
Carbon monoxide
Chlorine
2-Chloroethanol (ethylene chlorohydrin)
Chloropicrin (formerly agent PS)
2-Chlorovinylarsonous acid (CVAA)
Cyanide (OSF), free
Cyanide salts, as sodium cyanide for water, as
CN compounds in air (Cal/EPA, CAS 1-07-3)
Cyanogen chloride (agent CK)
Cyclohexyl sarin (agent GF, cyclosarin)
Dichloroacetic acid
1,2-Dichloroethane (ethylene dichloride)
Dichlorvos
67-64-1
116-06-3
1646-88-4
1646-87-3
107-18-6
7664-41-7
7440-38-2
7784-42-1
1332-21-4
71-43-2
10043-35-3
10294-34-5
7637-07-2
28772-56-7
7440-43-9
1563-66-2
75-15-0
630-08-0
7782-50-5
107-07-3
76-06-2
85090-33-1
57-12-5
143-33-9
506-77-4
329-99-7
79-43-6
107-06-2
62-73-7
32,000
35
35
35
180
34,000
10

(210)
7MF/L
5
10,500
(7,000)
(2,100) (1,400)
(0.7)
5
40
3,500

4,000

50
(3.5)
200
1,400
1,800 (750)
0.14
60
5
0.28





100 (70)
0.0002
0.05
(0.012)
400 f/m3
0.13


0.7

0.0006

700
10,000
0.2

0.4
0.11
9
9
9.0
0.001

0.04
0.5
Contaminant
Dicrotophos (Bidrin)
NA Diesel engine exhaust (mixture)
CAS, Cal/EPA
2-Diisopropylaminoethanol
S-[2-(diisopropylamino)ethyl]MPTA (EA 2192)
Diisopropyl ethyl mercaptoamine (DESH)
1 ,2-Diisopropyl methylphosphonate (DIMP)
Dimethyl phosphite (DMP or DMHP)
Dimethylamine
1,4-Dithiane (diethylene disulfide)
Divinyl sulfone
Ethyl sarin (agent GE)
Ethylbenzene (gasoline range organics)
Ethylene glycol
Ethylene oxide (Oxirane)
O-ethyl methylphosphonic acid (EMPA)
O-ethyl methylphosphonothioic add (EMPTA)
Fenamiphos
Fenamiphos sulfone
Fenamiphos sulfoxide
Fluorine (as soluble P in water, HP in air)
Formaldehyde
Furan
Gasoline (CAS number is for gasoline vapors)
n-Hexane (gasoline range organics)
Hydrogen chloride (HC1)
Hydrogen cyanide (HCN, agent AC)
Hydrogen fluoride (HF) (as F" in water)
Hydrogen sulfide
Isopropanol
Isopropyl methylphosphonic acid (IMPA)
Kerosene
Lewisite-1 (agent L-l)
CASRN
141-66-2
(9-91-1)
96-80-0
73207-98-4
5842-07-9
1445-75-6
868-85-9
124-40-3
505-29-3
77-77-0
1189-87-3
100-41-4
107-21-1
75-21-8
1832-53-7
18005-40-8
22224-92-6
31972-44-8
31972-43-7
7782-41-4
50-00-0
110-00-9
1-11-0
110-54-3
7647-01-0
74-90-8
7664-39-3
7783-06-4
67-63-0
1832-54-8
8008-20-6
541-25-3
Concn.
in Water
(mIL)
3.5 (0.2)

290
0.021
130
2,800 (600)
1,500

350 (80)
(0.25)
(0.7)
700
70,000 (14,000)
8
980
250
8.8 (1)
(8.8) (1)
(8.8) (1)
4,000
7,000 (1,000)
35

2,100

700
4,000
200

3,500 (700)

3.5
Concn.
in Air
(ftg/m3)
NA
5 (0.33)
10
0.0007
4.6

420
2


NA
1,000
400
30 (1.1)
34
8.5
(1.4)
(1.4)
(1.4)
(14)
0.08

2,100
700
20 (9)
3
14
2
7,000

10
3

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Table 12  Summary of Risk-Based Criteria as Analytical Method Validation Targets for Water and Air
Contaminant
Lewisite-2 (agent L-2)
Lewisite-3 (agent L-3)
Lewisite oxide
Mercuric chloride, as mercury (inorganic)
Methanol
Methyl isocyanate
Methyl paraoxon
Methyl parathion
Methylphosphonic acid (MPA)
Mevinphos (Phosdrin)
Mustard, sulfur (agent H) and distilled agent HD
Mustard HT (agent HT: 60% HD, 40% T)
Mustard sulfone
Mustard sulfoxide
Nicotine
Nitrate (NO3~)
Nitric acid (fuming, FNA) (as nitrate in water)
Nitrogen oxides (as NO ; nitrite in water)
p-Nitrophenol (para- or 4-nitrophenol)
Oxamyl (Vydate)
Ozone (Oj)
Paraquat (dichloride)
Perfluoroisobutylene (PFIB)
Phenol
Phorate (Thimet)
Phorate sulfone
Phorate sulfoxide
Phosgene
Phosphine
Phosphoric acid
Polychlorinated biphenyls (PCBs)
Propylene oxide
CASRN
40334-69-8
40334-70-1
3088-37-7
7487-94-7
67-56-1
624-83-9
950-35-6
298-00-0
993-13-5
7786-34-7
505-60-2
HD: 505-60-2
T: 63918-89-8
471-03-4
5819-08-9
54-11-5
14797-55-8
7697-37-2
10102-44-0
100-02-7
23135-22-0
10028-15-6
1910-42-5
382-21-8
108-95-2
298-02-2
2588-04-7
2588-03-6
75-44-5
7803-51-2
7664-38-2
1336-36-3
75-56-9
Water
Concn
(mIL)
(3.5)
(3.5)
(3.5)
11 (2)
18,000

(Q.SS)(0.2/0.018)
8.8 (2/0.18)
700
8.8
0.25
0.25
(0.25)
(0.25)
70
10,000
(10,000)
(1,000)
280
200

160 (30)

11,000
(2,000)
7
6
6

11
12,000
0.5
0.1
Air
Concn
(ftg/n?)
(3)
(3)
0.11
0.09
4,000
1
0.01
0.01
24

0.02
0.02
(0.02)
(0.02)


(86)
100
0.1

160
(0.01)
(0.3)
200



0.3
0.3
10
0.01
0.3
Contaminant
Red phosphorous (RP)
Sarin (agent GB)
Sodium fluoroacetate (for fluoroacetate salts)
Soman (agent GD)
Strychnine
Sulfate (for air, Cal/EPA lists as CAS 9-96-0)
Sulfur dioxide (as sulfate in water, see above)
Sulfuric acid (as sulfate in water)
Tabun (agent GA)
Tear gas (agent CS, per form CN, 532-27-4)
Thiodiglycol (TDG)
Titanium tetrachloride (agent FM)
Toluene (gasoline range organics)
Trimethyl phosphite (TMP)
VX
Xylenes (gasoline range organics)
Radionuclides
Americium-241 (7440-35-9)
Californium-252 (7440-71-3)
Cesium-137 (7440-46-2)
Cobalt-60 (7440-48-4)
Curium-244 (7440-51-9)
Europium- 154
Iridium-192
Plutonium-238 (7440-07-5)
Plutonium-239 (7440-07-5)
Polonium-210 (7440-08-6)
Radium-226 (7440-14-4)
Ruthenium-1 03
Ruthenium-1 06
Strontium-90 (7440-24-6)
Uranium-238 (7440-61-1)
CASRN
7723-14-0
107-44-8
62-74-8
96-64-0
57-24-9
9-96-0
7446-09-5
7664-93-9
77-81-6
2698-41-1
111-48-8
7550-45-0
108-88-3
121-45-9
50782-69-9
1330-20-7

14596-10-2
13981-17-4
10045-97-3
10198-40-0
13981-15-2
15585-10-1
14694-69-0
13981-16-3
15177-48-3
13981-52-7
13982-63-3
13968-53-1
13967-48-1
10098-97-2
7440-61-1
Water
Concn
(mIL)
(0.7) (0.1)
0.7
0.7
0.14
11
500,000
(500,000)
(250,000)
1.4

14,000

1,000
(1,500)
0.021
10,000

5.3 xlO'6
3.0 x 10'8
7.6 x 10'7
1.2 xlO'7
2.8 x 10'7
8.5 x 10'7
3.6 x 10'8
7.6 x 10'7
2.1 x 10'4
1.1 X 10'9
5.2 x 10'6
2.0 x 10'8
1.7 xlO'8
2.0 x 10'7
30
Air
Concn
(itgln?)
(10)
0.001

0.001

25
79
1
0.001
(0.03)

0.1
5,000 (300)

0.0006
100

1.9 xlO'9
6.7 xlO'12
2.2 x 10'7
4.7 xlO'9
8.4 x 10'11
3.3 x 10'9
7.8 x 10'10
3.1 x 10'10
8.4 x 10'8
3.3 x 10'12
1.4 x 10'8
6.3 x 10'10
5.2 xlO'10
1.1 x 10'8
1.4 x 10'2

-------
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-------
    Fate products of priority chemical contaminants and additional chemical agents with
health-based benchmarks are italicized in the individual results Tables 5 to 8 (Chapter 4).
For the radionuclides, radioactive progeny of potential dosimetric importance are listed
in Table 10. With the exception of certain members of the uranium-238 decay chain, it
was concluded that intake of accompanying radioactive progeny in water or air typically
would not add significantly to the radiation dose resulting from intake of the primary
radio nuclide.
    Of the primary contaminants and fate products assessed, many are volatile or
SVOCs. These can be lost from air via three primary mechanisms:  (1) reaction with
the hydroxyl radical or other reactive species such as ozone and nitrate radicals; (2) wet
deposition, or washout; and (3) dry deposition, or gravitational settling. The atmospheric
lifetime of volatile organic compounds (VOCs) is generally determined by their chemical
reactivity with the hydroxyl radical in the atmosphere. Highly reactive compounds such
as alkenes, or olefins (e.g., allyl alcohol), react rapidly with this radical, so atmospheric
lifetimes are on the order of hours to a day. The reaction rates for more stable alkane
compounds such as ethane and propane are a function of the length of the carbon chain.
For example,  decane (with ten carbons, which typically constitutes  20% of kerosene, a
contaminant  from the SAM report) would react with a lifetime of less than a day, while
ethane (with two carbons) would react much more slowly, with a lifetime on the order
of a month. Thus, VOCs exhibit a range of atmospheric lifetimes that can extend from
hours to months.
    SVOCs will also react with hydroxyl radicals in the atmosphere but at a much
slower rate. Primary loss for these compounds is due to their partitioning from the gas
to the particle phase in the atmosphere. The tendency to partition into the gas phase is
a function of temperature, with more of the compound in the particle phase at colder
temperatures. Once in that phase, contaminants would be removed from the atmosphere
at the same rate as the particle washout rate, which generally ranges from a week to a
month depending on  geographical location. However, certain semivolatile compounds
can persist in the atmosphere for a long time, in some cases for more than a year;  this
has led that group of chemicals to  be referred to as persistent organic pollutants. Their
atmospheric persistence is thought to result from the distillation effect, which reflects the
tendency of gases to re-evaporate in warmer seasons after being deposited onto surfaces,
then repartition into the particle phase during the next cold spell. This process has
generally resulted in these pollutants migrating north toward cold polar regions.
    This discussion is relevant to the portion of a given compound such as a
pesticide that is in the vapor phase and hence transportable in air. As a practical matter,
if SVOCs were sprayed (e.g., from an airplane or mechanical sprayer), not all of the
chemical would be expected to exist in the gas phase. Under those conditions, small
droplets or aerosols would likely exist, which would stick to earth or plant surfaces
relatively quickly due to gravitational settling. Thus, this aerosolization mechanism
(with some portion of a sprayed pesticide naturally vaporized during application) could
enhance the adherence of pesticides to such surfaces. Note that atmospheric lifetime here
represents how long a species typically resides in the atmosphere before being removed; it
is mathematically defined as the time it takes the initial concentration of the given species
to decrease by a factor of l/e (or 1/2.72), e.g., following a discrete release. For example,
if 100 g/m3 of a chemical were released to  air all at once, then its atmospheric lifetime
would be the time it takes that amount to be reduced to 37 g/m3.
                                                                                                          57

-------
                               A more extensive fate overview was developed to reflect characteristics of the
                           chemical in that medium, not the basic properties of a pure liquid as reported in
                           common data sources. When quantitative data were not readily available, descriptors
                           of low, medium, or high were estimated from chemical structures using the general
                           categories in Box 5-
Solubility and Volatility Indicators for Chemicals in Water (Box 5)
Property
Solubility
Volatility
Low
1,000 mol/L atmosphere (atm)
Medium \
1,000 to 10,000 ppm ;
1 to 1,000 mol/L atm j
High
> 10,000 ppm
<1 mol/L atm
                               The volatility descriptor was determined by considering the general magnitude of
                           Henry's Law constant (KH) for each chemical. This constant describes the equilibrium
                           concentrations in water and overlying air in a closed system. It is useful for evaluating
                           both water solubility and volatility in air, i.e., the vapor pressure or expected vapor
                           pressure of the pure substance. For example, the volatility of chlorine gas (C12) from
                           drinking water would be categorized as high because of its limited water solubility and
                           high vapor pressure, as would the volatility of other similar chemicals that are gases or
                           vapors at typical drinking water temperatures. To estimate the solubility descriptor,
                           the ionization state of the chemical at neutral pH was considered together with the
                           chemical structure. Substances that are ionic at neutral pH were categorized as having
                           high solubility. For example, phosphoric acid, a degradation product of a number of
                           study chemicals, falls in this category because at neutral pH it would primarily exist
                           as the dissociated anion (or in this case, anions). For nonionic chemicals, the presence
                           of particular functional groups was considered in determining the solubility indicator.
                           Solubility was considered high for chemicals with phenolic  (OH), carboxylic acid
                           (COOH), or amino (NH ) groups due to their ability to participate in hydrogen
                           bonding with water. The presence of carbonyl (C=O), ether (C-O-C), or heterocyclic O
                           or N groups was associated with medium solubility. The absence of any of these or other
                           polar groups was associated with low water solubility. Molecular weight was considered a
                           modifying factor, with solubility generally decreasing with increasing molecular weight.
                               These physical-chemical properties are used to assess whether a chemical in water
                           could be an inhalation threat. With the KH indicating the ratio of a chemical's volatility
                           to its solubility, it can be used to evaluate the significance of volatilization from water in
                           the following way. Chemicals with a KH less than 1 x 10"5 atm-m3/mole and a molecular
                           weight (MW) above 200 g/mole are unlikely to pose an inhalation hazard as a result
                           of volatilization from drinking water in a residential setting  (EPA 2004d). To illustrate,
                           consider methyl parathion with a MW of 263 g/mole and a KH of 1 x 10"7 atm-m3/
                           mole. If this chemical were released to a drinking water supply, it would not be expected
                           to pose an inhalation hazard.  The compound would stay in solution with very little
                           partitioning to air.
                               This study focuses on low validation targets to support  final decontamination.
                           Nevertheless, fate information is also used to indicate what contaminants could
                           best guide the assessment of performance for health protection across response
                           phases, beginning with the release and extending through interim measures to final
                           decontamination. A sentinel or companion "check-contaminant" can also be useful,
58

-------
especially when it can be detected relatively easily and inexpensively In addition to
those readily measured, validation efforts can focus on a core set of contaminants by
considering the relative amounts formed. Data on structures and illustrative equations
that include molar ratios can be used to indicate those amounts.
    Combining fate information with other context, including threat and relative
toxicity, can help prioritize validation efforts on those contaminants that matter most for
health protection. This approach is straightforward when detection capabilities relative
to the target concentrations are similar across persistent chemicals, so assuring baseline
validation below health-based levels for those contaminants is key. Fate information also
helps identify supporting candidates such as generally benign chemicals that would not
pose a health threat to those conducting the analyses.
    Certain fate products are associated with a number of threat contaminants, and for
these, fate/persistence data can be combined with toxicity data to focus on key surrogates
and indicators.
    For example, multiple threat chemicals introduced to water would produce
hydrogen chloride (HC1) with a relatively short half-life of hours to days. Thus, HC1
would be a useful detection indicator as well as a practical surrogate because it would
lower the pH of the water, which could be readily detected via  in-stream monitoring.
Two other highly stable chemicals are fate products for several contaminants:
methylphosphonic acid (MPA) and phosphoric acid. These two would also be candidates
for broad detection strategies designed  to monitor water for potential releases.
    In summary, fate information is crucial to effective method validation, in order
to understand the type and timing of other contaminants expected to form in water
and air after an original chemical is released. It is particularly important for short-lived
contaminants, to assure the identification of associated products that could drive health
concerns and cleanup issues. The initial fate overview in this report can also be used to
frame streamlining and prioritization activities for method validation. Joint consideration
of relative toxicity (discussed next) is important for those analyses.

5.2  Benchmark and  Method Coverage
With the aim of providing some context for method validation for all chemicals
and radionuclides, this report provides risk-based criteria from  benchmarks for
numerous threat contaminants and fate products. These concentrations cover the
majority of the  contaminants from the NHSRC list.
      This report focuses on chronic benchmarks, so a number of coverage "gaps" are
actually appropriate. In contrast, coverage is complete across all radionuclides that
would persist with half-lives of more than a month (ruthenium-103) to several billion
years  (uranium-238). Values are identified for each isotope in both media, with most
calculated from standard EPA dose limits.
    Gaps are primarily due to incomplete coverage of chemical agents (water and air)
and pesticides (air). The same pattern is seen across agents and  industrial chemicals in the
other contaminant sets.
    Of the main threat contaminants with at least one risk-based criteria, most have
values for drinking water, and many have values for air. The bulk of the total values
identified for the primary contaminants are from directly relevant benchmarks.
    For the rest, some are represented by analogues and others are represented by fate
products, notably for chemicals that do not persist, such as arsine, nitrogen mustard, and
                                                                                                         59

-------
                           tear gas in water; a few are derived from route-related limits, such as oral tolerances for
                           pesticide residues for bromadiolone, ethylene oxide, and nicotine.
                               The basic principle of this effort is that when a chronic public benchmark was not
                           found, further sources were evaluated in an effort to provide at least preliminary context
                           for validation targets for all the threat contaminants identified in the NHSRC list and
                           SAM report. This approach provides a basic guide for future research and development.
                               Part of the further evaluation for chemicals without chronic public benchmarks
                           involved checking occupational levels from OSHA, NIOSH, and ACGIH for workplace
                           air. These limits address exposures of 8 or 10 hours a day and 5 days a week over a
                           working lifetime, which aligns with the chronic duration of interest for this study.
                           Military exposure guidelines for air and water and additional airborne exposure limits for
                           deployed personnel are the primary sources for chemical agents. In contrast to the split
                           for chronic public benchmarks, most (above 80%) are for air. Many address common
                           environmental contaminants for which EPA limits also exist.
                               This report focuses on chronic public benchmarks. Reviewing occupational
                           benchmarks can support insights regarding other analyses that have been conducted,
                           with an emphasis on limits that are explicitly health-based, such as the TLVs and
                           many (not all) RELs and PELs, and also extending to the German limit, maximale
                           arbeitsplatzkonzentration (MAK). Furthermore, analogues or other surrogates can be
                           considered for insights into relative toxicity.
                               That information can be combined with emergency response levels for acute
                           exposures such as AEGLs and temporary  emergency exposure limits (TEELs) to
                           determine whether integrated comparisons may support bounding context for method
                           validation. Through these further reviews, preliminary information is available as initial
                           support  for method  validation for at least one medium for all the threat chemicals.
                               In summary, combining the validation targets developed in this report with the
                           analytical limits from the SAM report highlights opportunities for filling key gaps
                           in both method and benchmark coverage. Follow-on evaluations would be expected
                           to consider three areas: (1) sufficiency of method  coverage, for example considering
                           screening and definitive methods and both primary and backup options; (2) more
                           detail regarding analytical limits for individual contaminants, rather than broad ranges,
                           to assure that health-based targets can be adequately measured; and (3) refinement of
                           certain benchmark bases, including to address conservatism (some risk-based criteria
                           are represented by benchmarks for related chemicals, including more toxic parent
                           compounds).
60

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This integrated evaluation of chronic public benchmarks and contaminant fate
has identified more than 200 risk-based criteria as method validation targets across
numerous contaminants and fate products in drinking water and air combined. The gap
in directly applicable values is considerable across the full set of threat contaminants, so
preliminary indicators were developed from other well-documented benchmarks to serve
as a starting point for validation efforts. By this approach, at least preliminary context is
available for water or air, and sometimes both, for all chemicals on the NHSRC list that
was provided for this evaluation. This means that a number of concentrations presented
in this report represent indirect measures derived from related benchmarks or surrogate
chemicals, as described within the results tables.
    The main findings of this evaluation to identify risk-based method validation
targets are as follows:
    1.  Chronic benchmarks provide a useful basis for some low risk-based targets for
        analytical methods. Directly applicable,  contaminant-specific public benchmarks
        for drinking water and air are somewhat limited across the entire suite of
        contaminants.  Coverage is complete for the 15 radionuclides and about half the
        chemicals.
    2.  This report provides benchmarks for surrogates or fate products, as well as route-
        related benchmarks. Food residue limits for several pesticides and safety levels
        for biological contaminants  in foods contribute to further coverage. A risk-based
        chronic exposure concentration is available in at least one medium for a majority
        of the threat contaminants. The same split applies as for  the direct benchmarks,
        with more targets available for water than for air.
    3-  A fate analysis is essential to understanding the identity and timing of relevant
        degradation products that would form in water and air, so validation targets can
        also be identified for those compounds posing legitimate concern.
    4.  For chemicals lacking chronic public benchmarks, workplace limits for long-
        term exposures can be considered for context, prioritizing those that are explicitly
        health-based.
    5.  For chemicals lacking both chronic public and occupational benchmarks,
        depending on the contaminant and data available, information from acute
        exposure guidelines (usually derived from a level of health effect) can be
        compared with other guides and relative toxicity information to develop
        bounding context for method validation.
    6.  Preliminary context is provided for method validation in at  least one medium
        for all threat chemicals in the NHSRC list, by integrating information on
                                                                                                          61

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                                   related benchmarks, relative toxicity, and fate. One step that can be taken
                                   to address benchmark gaps across media is to evaluate the toxicity data for
                                   these contaminants, including the data underlying existing benchmarks.
                                   Contributions from other routes including dermal exposures also need to be
                                   specified where those data exist.
                                7-  A key gap for fate information is the identification of radical oxidation products
                                   in air. Although half-lives have been measured or can be generally estimated,
                                   specific identities are often missing. This gap limits the determination of
                                   benchmarks for a number of specific fate products in air that might pose health
                                   concerns.
                                8.  For toxicity gaps, no-observed-adverse-effect levels to support chronic
                                   benchmarks are lacking for a number of chemicals, as are quantitative
                                   considerations of sensitive subgroups within many existing benchmarks. To fill
                                   such gaps, downward adjustments can be applied to account for uncertainty.
                                9-  This report provides information useful in streamlining and prioritizing method
                                   validation and health-based evaluations. Fate, relative toxicity, and method limits
                                   are considered.

                                Taken together, this information can be used to guide effective method validation for
                            all the threat contaminants on the NHSRC list.
                                Other areas that may be considered for further research are as follows:
                                1. Combine fate, benchmark, and validation data to target the development  of
                                   quick-turnaround methods for short-lived, relatively toxic contaminants  that are
                                   considered priority threats per ongoing threat and vulnerability assessments to
                                   ensure faster detection  (and support faster implementation of exposure controls).
                                2.  Consider whether additional analyses are warranted, particularly for
                                   nonpersistent compounds, when detection limits are  higher than or close to
                                   chronic benchmark concentrations.
                                3-  Address other exposure routes, including dermal absorption, to support route-
                                   specific validation targets and route-integrated targets for joint exposures  to water
                                   and air; include fate/partitioning analyses in addressing multi-route contributions
                                   to those combined concentration targets.
                                4.  Assess benchmarks for  other durations  (subchronic, short-term, and acute) to
                                   identify validation targets for initial and intermediate response intervals.
                                5.  Integrate these data to identify broad indicator contaminants for sentinel
                                   detection, surrogates, and primary and  check contaminants for streamlined
                                   validation.
                                6.  Prioritize contaminants with the most significant gaps by overlaying benchmark
                                   gaps with fate and toxicity data (and results of ongoing threat and vulnerability
                                   assessments); assess other occupational limits (including MAKs), and incorporate
                                   context from those and other advisories to refine targets as indicated and
                                   determine where few data are available  to guide health-based detection (and
                                   response).
                                7-  As needed, pursue focused laboratory research to fill gaps in fate product
                                   identities (notably from radical oxidation reactions in air)  and their persistence,
62

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        so analytical methods can be assessed or developed and specific toxicities can be
        addressed, including via extrapolation approaches.
    8.  As needed, pursue focused laboratory research and coordinate with ongoing
        studies to fill gaps in toxicity knowledge; these range from basic toxicity studies
        to the development of tailored extrapolation methods that incorporate physical,
        chemical, and toxicological properties through quantitative structure-activity
        relationships, benchmark dose/concentration analyses, neural networks, and
        uncertainty analyses with Bayesian belief networks. With this information,
        analytical methods  can be assessed or developed to align with health-based levels.

    In summary, health-based information provides a crucial foundation for validation
of analytical methods. Gaps identified in this study can help  frame research and
development for analytical methods as well as related fate and toxicity analyses.
Combining information on fate, benchmarks, toxicity, and analytical methods
strengthens the validation effort as well as other ongoing health-related research within
NHSRC.
                                                                                                           63

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64

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                                                                                                        65

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66

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                                                                                                     67

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                          DoD, 2002, Technical Report, Modeling and Risk Characterization of U.S. Demolition
                          Operations at the Khamisiyah Pit, Washington, DC (April 16); Appendix B III;
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                          for Chemicals of Concern, Office of Environment, Safety, and Health, Washington, DC
                          (Oct.); http://www.eh.doe.gov/chem safety/ teel.html.

                          Elliot, S., G.E. Streit, J.  Gaffney, J.E. Bossert, M. Brown, J. Reisner, and L.A McNair,
                          1988, Pathways for the Oxidation of(Sarin) in Urban Atmospheres, LA-13501-MS,
                          UC-700, prepared by Los Alamos Laboratory, Los Alamos, NM (Sept.);
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                          Elliot, S., G.E. Streit, J.  Gaffney, J.E. Bossert, M. Brown, J. Reisner, and L.A. McNair,
                          1989, "Pathways for the Oxidation of Sarin in Urban Atmospheres," Environmental
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                          Endo, A, Y. Yamaguchi, and K. E Eckerman, 2005, Nuclear Decay Data for Dosimetry
                          Calculations — Revised Data oflCRP Publication 38, Japan Atomic Energy Research
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                          EPA 1988, Available online at http://www.epa.gov/iris/subst/0103.htm.

                          EPA (U.S. Environmental Protection Agency), 1989, Risk Assessment Guidance for
                          Superfund:  Volume 1, Human Health Evaluation Manual (Pan A), EPA/540/1-89/002,
                          Office of Emergency and Remedial Response, Washington, DC;
                          http://www.epa.gov/oswer/riskassessment/ ragsa/index.htm.

                          EPA, 1990, Available online at http://www.epa.gov/iris for the following entries:
                          Fenamiphos, Fenamiphos sulfoxide, and Formaldehyde.

                          EPA, 199la, Reregistration Eligibility Document (RED), Carbon and Carbon Dioxide,
                          Office of Pesticide Programs (Sept.); http://www.epa.gov/oppsrrdl/REDs/4019red.pdf.

                          EPA, 1991b, Guidance  on implementing the radionuclide NESHAPS. USEPA Office of
                          Radiation Programs. July 1991. Available online at http://www.epa.gov/rpdwebOO/docs/
                          neshaps/nesh implement 07 91.pdf

                          EPA, 1993, Available online at http: //www. ep a. gov/iris for the following entries:
                          Dichlorvos, Methanol, Hydrogen cyanide, Red phosphorus, Phosphine, and Isopropyl
                          methylphosphonic acid.

                          EPA, 1994, Reregistration Eligibility Document, Boric Acid and Its Sodium Salts, List A,
                          Case 0024, Office of Pesticide Programs, Washington, DC (Feb. 16);
                          http://www.epa.gov/oppsrrdl/REDs/old reds/boric acid salts.pdf
68

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EPA, 1995a, Registration Eligibility Decision (RED), Sodium Fluoroacetate, List C,
Case 3073, EPA738-R-95-025, Office of Prevention, Pesticides and Toxic Substances,
Washington, DC (Sept);
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EPA, 1995b, Available online at http://www.epa.gov/IRIS/subst/0024.htm.

EPA, 1996, National Toxics Rule: Remand of Water Quality Criteria for Dioxin and
Pentachlorophenol to EPA for Response to Comments. Federal Register Environmental
Documents. Federal Register. December 11, 1996 (Volume 61, Number 239)
http://www.epa.gov/fedrgstr/EPA-WATER/1996/December/Day-11 /pr-21087.html.

EPA, 1997a, Exposure Factors Handbook, EPA/600/P-95/002F, Office of Research and
Development, Washington, DC (Aug.); http://www.epa.gov/ncea/exposfac.htm.

EPA, 1997b, National Ambient Air Quality Standards (NAAQS), Office of Air and
Radiation, Washington, DC; http://www.epa.gov/air/criteria.html.

EPA, 1997c, Registration Eligibility Decision (RED), Paraquat Dichloride,
EPA738-F-96-018, Office of Prevention, Pesticides and Toxic Substances, Washington,
DC (Aug.); http://www.epa.gov/oppsrrdl/REDs/0262red.pdf

EPA, 1998a, Registration Eligibility Decision (RED), Rodenticide Cluster,
EPA738-R-98-007, Office of Prevention, Pesticides and Toxic Substances, Washington,
DC (July); http://www.epa.gov/oppsrrdl/REDs/2100red.pdf

EPA, 1998b, Table 3, Chronic Toxicity of Pesticides Detected by the U.S. Department of
Agriculture (USDA) Pesticide Data Program, 1994 - 1998. http://ecologic-ipm.com/
PDP/Table3  1998.pdf

EPA, 1999a, Human Health Risk Assessment, Fenamiphos, Health Effects Division
(7509C), Office of Pesticide Programs, Washington, DC (Sept. 2);
http://www.epa.gov/pesticides/op/ fenamiphos/hedsep99.pdf

EPA, 1999b, Cancer risk coefficients for environmental exposure to radionuclides.
Federal Guidance Report No. 13,  EPA 402-R -99-001. Prepared by Eckerman, K. F;
Leggett, R. W; Nelson, C.  B.; Puskin, J. S.; Richardson, A. C.  B.

EPA, 2000b, Report on FQPA Tolerance Reassessment Progress and Interim Risk
Management Decision, Mevinphos, EPA738-R-00-014, Office of Prevention, Pesticides
and Toxic Substances, Washington, DC (Sept.);
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EPA, 2000c, Oxamyl (103801) Registration Case No. 0253; Revised Anticipated Residue
and Acute and Chronic Dietary Exposure Estimates, memorandum from J.S. Punzi to  C.
Jarvis, Health Effects Division, Office of Prevention, Pesticides and Toxic Substances,
Washington, DC (March 9th);
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                                                                                                      69

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                          EPA, 2000d, IRED, Oxamyl, EPA738-R-00-015, Health Effects Division (7508C),
                          Office of Prevention, Pesticides and Toxic Substances, Washington, DC (Oct.);
                          http://www.epa.gov/oppsrrdl/REDs/0253ired.pdf.

                          EPA, 2000e, Phosgene Hazard Summary — Created in April 1992; Revised in January
                          2000, Fact Sheet on EPA's Technology Transfer Network Air Toxics Web site,
                          Washington, DC (Jan.); http://www.epa.gov/ttn/atw/hlthef/phosgene.html.

                          EPA, 2000f, Report on FQPA Tolerance Reassessment Progress and Interim Risk
                          Management Decision, Mevinphos, Office of Prevention, Pesticides and Toxic
                          Substances, Washington, DC (Sept.); http://www.epa.gov/pesticides/reregistration/
                          REDs/0250tred.pdf.

                          EPA, 2000g, National Primary Drinking Water Regulations; Radionuclides; Final Rule.
                          Federal Register: December 7, 2000 (Volume 65, Number 236). 40 CFR Part 141 (65
                          FR 76708)  Federal Register Environmental Documents.

                          EPA, 2001, IRED for Phomte, ListB, Case 0103, Office of Prevention, Pesticides and
                          Toxic Substances, Washington, DC;
                          http://www.epa.gov/oppsrrdl/REDs/phorate ired.pdf

                          EPA, 2002b, IRED, Fenamiphos, EPA738-R-02-004, Office of Prevention, Pesticides
                          and Toxic Substances, Washington, DC (May); http://www.epa.gov/oppsrrd 1 /REDs/
                          fenamiphos ired.pdf.

                          EPA, 2002c, Nicotine; Tolerance Revocations, Final Rule (40 Code of Federal Regulations
                          Part 180), Federal Register 67(99):359U-35915. July 1, Vol. 20;
                          http://www.epa.gov/fedrgstr/EPA-PEST/2002/May/Day-22/pl2423.htm.

                          EPA, 2003a, Human Health Toxicity Values in Superfund Risk Assessments, OSWER
                          Directive 9285-7-53, Office of Solid Waste and Emergency Response, Washington, DC
                          (Dec. 5); http://www.epa.gov/oswer/riskassessment/pdf/hhmemo.pdf.

                          EPA, 2003b, IRED for Methyl Parathion, Case No. 0153, Office of Prevention, Pesticides
                          and Toxic Substances, Washington, DC (IRED signed May); http://www.epa.gov/
                          oppsrrdl/REDs/methylparathion  ired.pdf.

                          EPA, 2004a, 2004 Edition of the Drinking Water Standards and Health Advisories (Winter
                          2004), EPA 822-R-04-005, Office of Water, Washington, DC;
                          http://www.epa.gov/waterscience/criteria/drinking/standards/dwstandards.pdf.

                          EPA, 2004b, Drinking Water Health Advisory for Oxamyl, EPA-822-B-04-002, Health
                          and Ecological Criteria Division, Office of Science and Technology, Office of Water,
                          Washington, DC (Sept.);
                          http://www.epa.gov/waterscience/criteria/drinking/oxamyl-dw-ha.pdf.
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EPA, 2004c, Guidelines Establishing Test Procedures for the Analysis of Pollutants; Procedures
for Detection and Quantitation, 40 CFR Part 136; Office of Science and Technology;
Office of Water; Washington, DC; Federal Register, 69(215):64704-7 (Nov. 8);
http://www.epa.gov/fedrgstr/EPA-WATER/2004/November/Day-08/w24824.htm.

EPA, 2004d, Users' Guide and Technical Background Document for U.S. EPA Region 9's
Preliminary Remediation Goals (PRG) Table, Region 9: Superfund (Dec. revision);
http://www.epa.gov/region09/waste/sfund/prg/files/04usersguide.pdf.

EPA, 2004e, Drinking Water; National Primary Drinking Water Regulations — Sulfate;
National Primary Drinking Water Regulation Implementation, Federal Register (Dec. 20);
http://www.epa.gov/fedrgstr/EPA-WATER/1994/December/Day-20/pr-32DIR/fulltext.
html.

EPA, 2004f, National Emission Standards for Hazardous Air Pollutants; National
Emission Standards for Emissions of Radionuclides Other Than Radon from
Department of Energy Facilities; National Emission Standards for Radionuclide
Emissions from Federal Facilities Other Than Nuclear Regulatory Commission Licensees
and Not Covered by Subpart H; Final Amendment—Correction. Federal Register. June
17, 2004 (Volume 69, Number 116). Federal Register Environmental Documents.
http://www.epa.gov/fedrgstr/EPA-AIR/2004/June/Day-17/al3679.htm.

EPA, 2005a, Standardized Analytical Methods for Use During Homeland Security Events,
Revision 2, Office of Research and Development, National Homeland Security Research
Center, Cincinnati,  OH (Sept.); http://www.epa.gov/nhsrc/pubs/reportSAM092905.pdf.

EPA, 2005b, Provisional Peer-Reviewed Toxicity Values for Ammonia (CAS RN 7664-41-7),
Superfund Health Risk Technical Support Center, Office of Research and Development,
National Center for Environmental Assessment, Cincinnati,  OH; 2-2-05 (accessed
electronically Nov.); http://hhpprtv.ornl.gov/ pprtv  papers.html.

EPA, 2005c, Propylene Oxide — Revised HED Risk Assessment for Reregistration Eligibility
Decision (RED) , PC Code: 042501, DP Barcode: D321759, Office of Prevention,
Pesticides, and Toxic Substances, Washington, DC (Sept. 26);
http://cfpub.epa.gov/oppref/rereg/ status.cfm?show=rereg.

EPA, 2006a, Envirofacts Master Chemical Integrator, Chemical References Complete
Index (accessed July 2006);
http://www.epa.gov/enviro/html/emci/chemref/complete  index.html.

EPA, 2006b, Integrated Risk Information System, online database, Office of Research
and Development, Washington, DC; http://www.epa.gov/iris. Note: IRIS was accessed
in November 2005 (with selected rechecks in January and July 2006), so the reference is
presented here as 2006. However, dates in the tables represent when the chemkal-specific
toxicity values were placed online (or in some cases further reviewed), so that time frame can be
appreciated when comparing with other benchmarks that may have been established earlier or
later.
                                                                                                       71

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                          EPA, 2006c, Acute Exposure Guideline Levels for Ethyldichloroarsine, OPPTS,
                          OPPT, Washington, DC (March.); http://www.epa.gov/oppt/aegl/restl36.htm.

                          EPA, 2006d, IREDfor Dicrotophos, (DDVP), Health Effects Division, Office of
                          Prevention, Pesticides and Toxic Substances, Washington, DC (June);
                          http://www.epa.gov/pesticides/reregistration/REDs/ddvp-ired.pdf.

                          EPA, 2006e, Finalization of IREDfor Phomte. OPPTS, OPPT. Washington, DC Quly);
                          http://www.epa.gov/oppirdl/reregistration/REDs/phorate.ired.pdf.

                          EPA, 2006f, Drinking water contaminants.
                          http://www.epa.gov/safewater/contaminants/index.html.

                          EPA, 2006g, IRED for Dicrotophos, Case No. 0145, Office of Prevention, Pesticides and
                          Toxic Substances, Washington, DC (July 31); http://www.epa.gov/oppsrrdl/REDs/
                          dicrotophos ired.pdf."

                          EPA, 2007a, Standardized Analytical Methods for Environmental Restoration following
                          Homeland Security Events. Revision 3-0. Office of Research and Development, National
                          Homeland Security Research Center, Cincinnati, OH.

                          EPA, 2007b, Memorandum: Use of Uranium Drinking Water Standards under 40 CFR
                          141 and 40 CFR 192 as Remediation Goals for Groundwater at CERCLA sites. From
                          Elaine F. Davies, Acting Director, Office of Emergency and Remedial Response (OERR),
                          and Stephen D. Page, Director, Office of Radiation and Indoor Air (ORIA), Office of
                          Air and Radiation. Last updated on Friday, March 23rd, 2007-
                          http://www.epa.gov/swerffrr/documents/uranium drinking water  standards.htm.

                          EPA Region 6, 2007,  Region 6 Human Health Medium-Specific Screening Levels.
                          Available online at http://www.epa.gov/earthlr6/6pd/rcra c/pd-n/screenvalues.pdf.

                          Ershow, A. G., and K. P Cantor, 1989,  Total Water and Tap Water Intake in the United
                          States: Population Based Estimates of Quantities and Sources, Order No. 263-MD-810264
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o
          Appendix A: Supporting  Details for
          Overall Approach and  Key Benchmarks

This appendix includes two figures (Al and A2) that illustrate a general process for
identifying risk-based target concentrations to help guide detection validation. One table
is also provided to support the analyses in the main body of this report, as described
below.

    Table Al: Illustrates further details for eight types of drinking water benchmarks,
           six based on concentrations and two on dose values. (This table is
           adapted from the summary in the recent standards and guidelines
           report for the NHSRC-ANL pilot drinking water study.) This
           information provides background context for the applicability of various
           benchmarks to support target concentrations for detection validation.
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Nl
00
Figure A1 Fate Evaluation to Identify Associated Chemicals for Detection Consideration, and Overview Benchmark Check
Assess
atmospheric fate
(persistence,
reactivity,
atmospheric half-life)
^
r
         Identify fate products
         (hydrolysis, oxidation,
         other transformation)
                                                                 What happens
                                                              when the chemical is
                                                                released to air or
                                                                drinking water?
                                                 Does it
                                           form other chemicals
                                                 in air?
                                                                                Does it
                                                                          form other chemicals
                                                                               in water ?
                                                                                                            Consider typical
                                                                                                       conditions for drinking water
                                                                                                            from surface and
                                                                                                          ground water sources
                                                                                                            (5-25°C, pH6-9,
                                                                                                           chlorine residuals)
                                                        Check for applicable
                                                      benchmarks in air, water
                                                        (concentration limits
                                                      and toxicity/dose values)
                      Consider OELs
                     for initial insights
                  (e.g. possible high bound)
                                                              Does an
                                                        applicable benchmark
                                                        exist? (general public,
                                                      chronic/repeat exposures,
                                                      nationally peer-reviewed)
Assess aquatic fate
(solubility,
persistence,
volatility,
hydrolysis half-life)
i
r
            Identify fate products
            (hydrolysis, oxidation,
            other transformation)
  See Figure A2:
check, adopt/adjust

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Figure A2 Example Evaluation Process for Chronic Concentrations
                   Does an
                  applicable
            concentration limit exist
          for air? For drinking water?
                (general public,
            chronic/repeat exposure,
                nationally peer-
                  reviewed)
                                                          For only one
                                                       effect endpoint per
                                                        route? (cancer or
                                                           noncancer)
               Does a standard
              toxicity value exist?
                (IRIS or PPRTV,
                   chronic)
                                                         For both routes?
                                                            (oral and
                                                            inhalation)
                                                    Consider route extrapolation ,
                                                    for possible insight; target
                                                    research to fill critical gaps
                                                                                   Determine
                                                                                 concentration
                                                                                  (e.g., 30-year
                                                                               exposure, 10~6risk)
                                                                                   Determine
                                                                             concentration for each
                                                                               endpoint and select
                                                                                 the lower value
        Defer to
   toxicity evaluations
to support development of
   provisional advisory
     levels (PALs) for
   homeland security
                                                                                   Determine
                                                                             concentration for each
                                                                              (assumptions above)
  Preliminary
 health-based
    target
concentrations
  for testing
   detector
  techniques

  (Can these
    levels
  be reliably
  measured?)
   Refine to
 reflect further
 toxicological
data evaluation

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00
o
Table A1 Overview Description of Exposure Criteria and Dose Benchmarks for Drinking Water3
Standard/Guideline and
Organization
Maximum contaminant level (MCL)
EPA Office of Water
Minimal risk level (MRL)
Agency for Toxic Substances and
Disease Registry
Drinking water equivalent level
(DWEL)
EPA Office of Water
Health advisory (HA)
EPA Office of Water
Drinking water level of comparison
(DWLOC)
EPA OFF
OralRfD
EPA ORD (IRIS)
Cancer slope factor (SF) and UR
PA ORD (IRIS)
Military exposure guideline (MEG)
US. Army CHPPM
Summary
Description
Enforceable concentration for public
water supplies, aims to protect the
population
Dose level based on NOAEL for
noncancer effects (MRLs also exist
for shorter exposure durations)
No-effect concentration from
multiplying the oral RfD by an adult
body weight and dividing by the
daily intake
Concentration in drinking water to
not produce any adverse noncancer
effects
Concentration as portion of pesticide
exposure from drinking water to not
cause any adverse noncancer effects
Estimate of daily oral exposure (dose)
likely to be without appreciable risk
of adverse noncancer effect over a
lifetime (including for susceptible
subgroups)
Plausible upper-bound probability
individual will develop cancer as a
result of exposure (dose) over lifetime
Operational concentration for
moderate and arid climates to
produce minimal to no adverse
effects, can adjust for public
Target
Group
General
public
General
public
General
public
General
public
General
public
General
public
General
public
Deployed
military
personnel
Exposure Parameters Assumed
Duration BodyWeight/ Intake
Chronic/lifetime I 70-kg adult I 2 L/d
Acute (1-14 d) | |
Intermediate (1 5-364 d) ! 70-kg adult ! 2 L/d
Chronic (>1 yr) 1 1
Chronic/lifetime j 70-kg adult j 2 L/d
Acute (Id, 10 d) | 10-kg child | IL/d
Chronic/lifetime j 70-kg adult j 2 L/d
Acute (Id), 1 10-kg infant, child 1 1 L/d
short-term (to 7 d), intermediate ! i
(3 month [mo]), I 60-kg adult female, j 2 ^
chronic (lifetime) j 70-kg adult male j
Chronic/lifetime I 70-kg adult I 2 L/d
Chronic/lifetime I 70-kg adult I 2 L/d
<7d,7-l4d ! !
j ! 5,151V
i /U-kg adult | .
lyr
Example of Chemicals
Covered
Arsenic, asbestos, carbofuran,
cyanide, fluoride, mercury
Arsenic, cyanide, dichlorvos,
DIMP, formaldehyde, methyl
parathion
Arsenic, carbofuran, cyanide,
cyanogen chloride, DIMP,
methyl parathion
Ammonia, cyanide, IMPA,
methyl parathion, oxamyl
Dicrotophos, fenamiphos,
methyl parathion
Aldicarb, carbofuran, carbon
disulfide, dicrotophos, furan,
methyl parathion, paraquat,
phenol, phosphine, strychnine
Arsenic, benzene,
1,2-dichloroethane, dichlorvos,
PCBs, propylene oxide
Carbofuran, carbon disulfide,
cyanide, methyl parathion,
oxamyl, paraquat
           a Examples illustrate several chemicals for which these benchmarks exist. Note that the levels identified for chronic (lifetime) exposures for the general public (e.g., MCL, RfD, and SF) incorporate consideration of children.

        DIMP = diisopropyl methylphosphonate; IMPA = isopropyl methylphosphonic acid; PCBs = polychlorinated biphenyls.

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