# United States Office of Water EPA-822-R-02-047

Environmental Protection Office of Science and Technology November 2002

Agency (4304T)



# National Recommended

Water Quality Criteria:

2002

# i 

# NOTICE

This document has been reviewed by the Health and Ecological Criteria Division, Office of

Science and Technology, U.S. Environmental Protection Agency, and approved for publication.

# ii 

# CONTENTS

NOTICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

I Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

II What is in this Updated Compilation? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

III What is the Relationship Between These Criteria and Your State or Tribal Water

Quality Standards? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

IV What is the Status of Existing Recommended Criteria While They Are Under Revision? . . 3

V What’s New in the Compilation? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Human Health Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Revised Human Health Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Methylmercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Dioxin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Aquatic Life Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Revised Definition of Total PCBs for Aquatic Life Criteria . . . . . . . . . . . . . . . . . 6

Saltwater Dissolved Oxygen (Cape Cod to Cape Hatteras) . . . . . . . . . . . . . . . . . 6

Freshwater Aquatic Life Criteria for Ammonia . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Cadmium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Guidance on the Calculation of Hardness-Dependent Metals Criteria . . . . . . . . . 7

National Guidance on the Applicability of Freshwater and Saltwater Criteria . . . 9

Nutrient Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

VI Comments on the December 10, 1998 National Recommended Water Quality

Criteria Compilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

VII Where Can I Find More Information About Water Quality Criteria and Water

Quality Standards? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

VIII What Are the National Recommended Water Quality Criteria? . . . . . . . . . . . . . . . . . . . . 11

General Notes: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Appendices: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Appendix A - Conversion Factors for Dissolved Metals . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Appendix B - Parameters for Calculating Freshwater Dissolved Metals Criteria

That Are Hardness-Dependent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Appendix C - Calculation of Freshwater Ammonia Criterion . . . . . . . . . . . . . . . . . . . . . . 33

# 1 

# I Introduction

The U.S. Environmental Protection Agency (EPA) is publishing an updated compilation of

its national recommended water quality criteria for 158 pollutants, developed pursuant to section

304(a) of the Clean Water Act (CWA or the Act). Section 304(a)(1) of the Act requires EPA to

develop and publish, and from time to time revise, criteria for water quality accurately reflecting

the latest scientific knowledge. Water quality criteria developed under section 304(a) are based

solely on data and scientific judgments on the relationship between pollutant concentrations and

environmental and human health effects. Section 304(a) criteria do not reflect consideration of

economic impacts or the technological feasibility of meeting the chemical concentrations in

ambient water.

The recommended water quality criteria contained in this document provide guidance for

states and tribes authorized to establish water quality standards under the CWA to protect human

health and aquatic life. Under the CWA, states and authorized tribes are to establish water

quality standards to protect designated uses. Such standards are used in implementing a number

of environmental programs, including setting discharge limits in National Pollutant Discharge

Elimination System (NPDES) permits. While this document constitutes the EPA’s guidance

regarding ambient concentrations for various pollutants, this document does not substitute for the

CWA or EPA’s regulations; nor is it a regulation itself. Thus, it cannot impose legally binding

requirements on the EPA, states, authorized tribes or the regulated community, and might not

apply to a particular situation based upon the circumstances. State and tribal decision-makers

retain the discretion to adopt approaches on a case-by-case basis that differ from this guidance

when appropriate. The EPA may change this guidance in the future.

II What is in this Updated Compilation?

EPA developed an updated compilation of its national recommended water quality criteria

(NRWQC) for pollutants. The criteria in this document supercede any Clean Water Act (CWA)

section 304(a) water quality criteria published in EPA’s previous criteria compilations including:

the “ Blue Book ,” “Red Book ,” “ Gold Book ” and EPA’s last compilation of national

recommended water quality criteria published on December 10, 1998 (63 FR 68354 or National

Recommended Water Quality Criteria– Correction , April 1999, EPA 822-Z-99-001). Many of

the human health criteria in this compilation have been revised based on EPA’s new

methodology for deriving human health criteria (See: Methodology for Deriving Ambient Water

Quality Criteria for the Protection of Human Health (2000), EPA-822-B-00-004, October 2000).

Water quality criteria contained in this document may be superceded by the publication of

section 304(a) water quality criteria subsequent to the publication of this document.

This compilation is presented as a summary table containing EPA’s water quality criteria

for 158 pollutants. For each set of criteria, EPA lists a Federal Register citation, EPA document

number or Integrated Risk Information System (IRIS) entry ( www.epa.gov/iris/index.html).

Information pertinent to the derivation of individual criteria may be found in the cited references

or footnotes. Still, these references may not be a single complete source of information for the

# 2 

# criteria derivation. You may need to refer to more than one document for complete information.

A calculation matrix that contains all of the components (e.g., cancer potency factors (q1*s),

reference doses (RfDs) and bioconcentration factors (BCFs)) and formulas used to derive the

human health criteria in the compilation is available at http://www.epa.gov/waterscience/criteria/

. EPA does not have national recommended water quality criteria for pollutants with no criteria

listed.

The national recommended water quality criteria include: previously published criteria that

are unchanged, criteria that have been recalculated from earlier criteria (63 FR68354,

12/10/1998) and newly calculated criteria base d on peer-reviewed assessments and data.

The Agency intends to revise this compilation of national recommended water quality

criteria from time to time to keep states and authorized tribes informed as to the most current

recommended section 304(a) water quality criteria.

III What is the Relationship Between These Criteria and Your State or Tribal Water

Quality Standards?

As part of the water quality standards triennial review process defined in Section 303(c)(1)

of the CWA, the states and authorized tribes are responsible for maintaining and revising water

quality standards. Water quality standards consist of designated uses, water quality criteria to

protect those uses, a policy for antidegradation, and general policies for application and

implementation. Section 303(c)(1) requires States and Tribes to review, and modify if

appropriate, their water quality standards at least once every three years.

States and authorized tribes must adopt water quality criteria that protect designated uses.

Protective criteria are based on a sound scientific rationale and contain sufficient parameters or

constituents to protect the designated uses. Criteria may be expressed in either narrative or

numeric form. States and authorized tribes have four options when adopting water quality

criteria for which EPA has published section 304(a) criteria. They can: (1) establish numerical

values based on recommended section 304(a) criteria; (2) adopt section 304(a) criteria modified

to reflect site-specific conditions; (3) adopt criteria derived using other scientifically defensible

methods; or (4) establish narrative criteria where numeric criteria cannot be determined (40 CFR

131.11).

Consistent with 40 CFR131.21 (See: EPA Review and Approval of State and Tribal Water

Quality Standards (65 FR 24641, April 27, 2000)), water quality criteria adopted by law or

regulation by States and Tribes prior to May 30, 2000, are in effect for CWA purposes unless

superseded by federal regulations (see, for example, the National Toxics Rule , 40 CFR 131.36;

Water Quality Standards for Idaho , 40 CFR 131.33). New or revised water quality criteria

adopted into law or regulation by States and Tribes on or after May 30, 2000 are in effect for

CWA purposes only after EPA approval.

# 3 

# IV What is the Status of Existing Recommended Criteria While They Are

Under Revision?

Water quality criteria published by EPA remain the Agency’s recommended water quality

criteria until EPA revises or withdraws the criteria. For example, while undertaking recent

reassessments of certain chemicals, EPA has consistently supported the use of the existing

section 304(a) criteria for these chemicals and considers them to be scientifically sound until the

Agency reevaluates the 304(a) criteria, subjects the criteria to appropriate peer review, and

subsequently publishes revised 304(a) criteria.

V What’s New in the Compilation?

Human Health Criteria

Revised Human Health Criteria

EPA revised the methodology it uses to develop water quality criteria for protection of

human health. The revised methodology entitled, Methodology for Deriving Ambient Water

Quality Criteria for the Protection of Human Health (2000) (EPA-822-B-00-004, October 2000)

and a Federal Register notice (65 FR 66443, 11/3/2000) both describe the Agency’s current

approach for deriving national recommended water quality criteria to protect human health.

EPA has revised many of the human health criteria in the compilation based on this new

methodology. By and large, these represent partial updates of the 304(a) criteria as described in

both the draft Methodology revisions and the Federal Register notice that accompanied the final

Methodology (65 FR 66443). EPA received much support for revising criteria based on partially

updated components of the criteria equations as a way of increasing the frequency of scientific

improvements to the nationally recommended criteria that currently available information would

allow. For a water quality criterion revision based on a partial update to be considered

acceptable to EPA, a component of the criterion (e.g., the toxicological risk assessment) would

need to be comprehensive (e.g., a new or revised RfD or cancer dose-response assessment, as

opposed to simply a new scaling factor), should stand alone and be based on new national or

local data. These recalculations of water quality criteria integrate an updated national default

freshwater/estuarine fish consumption rate (17.5 g/day) and, in some cases, previously

determined relative source contribution (RSC) values obtained from primary drinking water

standards as well as new cancer potency information from the Agency’s Integrated Risk

Information System (IRIS).

EPA has not revised the human health criteria in today’s compilation to include

bioaccumulation factors (BAFs) based on the 2000 Methodology. The BAF component of

criteria development is comparatively time- and resource-intensive. As previously indicated,

EPA received support for partial updates rather than waiting a substantially longer period of time

for BAFs to be developed. EPA also received support for the idea of not automatically

developing BAFs for all of the currently published criteria, but rather revising criteria for

# 4 

# pollutants of high priority and national importance. EPA intends to focus its limited resources on

developing BAFs for pollutants that the Agency considers highest priority in terms of

toxicological concern, frequency of occurrence and bioaccumulation potential. EPA is in the

process of determining candidate pollutants for BAF derivations. The human health criteria were

developed with BCFs or field-measured BAFs previously developed using the 1980

Methodology. The BCFs used in deriving these criteria are consistent with BCFs used in

promulgating human health criteria for priority toxic pollutants in rules such as the 1992

National Toxics Rule and the 2000 California Toxics Rule

.

Not all of EPA’s national recommended water quality criteria for protection of human

health were revised in this compilation. Criteria currently undergoing major reassessments, such

as arsenic, chloroform and nickel, were not revised at this time. Water quality criteria that predate

EPA’s 1980 human health methodology were not revised for this effort. EPA believes revisions

for these criteria, which include barium, 2,4-D and 2,4,5-TP, iron, manganese, methoxychlor,

nitrates and solids (dissolved) and salinity may warrant major reassessments. Updated IRIS

information and/or RSC values are available for vinyl chloride, 1,1-dichloroethylene, 1,3-

dichloropropene, thallium, chlorobenzene, cyanide, ethylbenzene, toluene, 1,2-transdichloroethylene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, hexachlorocyclopentadiene, 1,2,4-

trichlorobenzene, Lindane and Endrin. Yet, EPA did not update the criteria for the preceeding 15

chemicals in this document. EPA intends to publish revisions for the aformentioned chemicals in

a separate Federal Register notice, soliciting scientific views regarding these revisions.

New IRIS information was available and incorporated for benzene. EPA revised the

criteria for benzene based on the new cancer slope factors, which are presented in IRIS as a

range. The set of risk estimates falling within this interval reflects both the inherent uncertainties

in the risk assessment of benzene and the limitations of the epidemiological studies in

determining dose-response and exposure data. EPA modeled the unit risk values for the

carcinogenicity of benzene from epidemiological data on occupationally exposed humans. The

unit risk is expressed as a range rather than a single value because in the case of this particular

pollutant there is no scientific basis for choosing a single result from various model estimates.

(See IRIS Benzene CASRN 71-43-2 (01/19/2000) at: www.epa.gov/iris/subst/0276.htm). The

resulting ranges of criteria for protection of human health from consumption of water and

organisms and consumption of organisms only are 0.61- 2.2 ug/L and 14- 51 ug/L, respectively.

The Agency calculated the criteria as ranges, but is recommending the use of the upper limits in

the criteria table. EPA considers any criterion in each range scientifically defensible, yet only the

upper limit of each range is presented to establish the upper bound of the average ambient

concentration that should not be exceeded.

For copper and asbestos, the Agency chose to base the section 304(a) water quality

criteria on the Agency’s drinking water maximum contaminant levels (MCLs) or action levels

which are established on drinking water regulation methodologies.

A notice of intent to revise or develop human health criteria for arsenic, methylmercury

and carbofuran was published in the Federal Register on October 12, 2000 (65 FR 60664). This

# 5 

# notice informed the public that EPA was in the process of revising or developing criteria for

these pollutants and solicited any significant scientific information the public may be aware of

that was not identified in EPA’s literature search. A human health criterion for methylmercury is

now available. Work is ongoing for arsenic and carbofuran.

Methylmercury

On January 8, 2001, EPA announced the availab ility of a recommended water quality

criterion for methylmercury (66 FR 1344). In the January 8, 2001 notice, EPA withdrew its

previous ambient human health water quality criteria for mercury (see 63 FR 68354, December

10, 1998; correction in 64 FR 19781, April 22, 1999) as the recommended section 304(a) water

quality criteria. This updated compilation contains the new methylmercury criterion. This new

water quality criterion describes the concentration of methylmercury in freshwater and estuarine

fish and shellfish tissue that should not be exceeded to protect consumers of fish and shellfish

among the general population. EPA expects the criterion recommendation to be used as

guidance by states, tribes, and EPA in establishing or updating water quality standards for waters

of the United States and in issuing fish and shellfish consumption advisories. This is the first

time EPA has issued a water quality criterion expressed as a fish and shellfish tissue value rather

than as a water column value. This approach is a direct consequence of the scientific consensus

that consumption of contaminated fish and shellfish is the primary human route of exposure to

methylmercury. EPA recognizes that this approach differs from traditional water column criteria,

and will pose implementation challenges. In the January 8, 2001 notice EPA provided suggested

approaches for relating the fish and shellfish tissue criterion to concentrations of methylmercury

in the water column. EPA also plans to develop more detailed guidance to assist states and

authorized tribes with implementation of the methylmercury criterion in water quality standards

and related programs.

Dioxin

The section 304(a) water quality criteria for dioxin contained in this compilation is

expressed in terms of 2,3,7,8-Tetrachloro-dibenzo-p-dioxin (2,3,7,8-TCDD) and should be used

in conjunction with the national/international convention of toxicity equivalence factors

(TEF/TEQs) to account for the additive effects of other dioxin-like compounds (dioxins). EPA

supports the use of either the 1989 interim procedures or the 1998 World Health Organization

(WHO) TEF scheme, but prefers the 1998 WHO TEF scheme because it is based on more recent

data and is internationally accepted. (See: Update to the Interim Procedures for Estimating Risks

Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-dioxins and -dibenzofurans

, EPA/625/3-89/016, March 1989 and Van den Berg M., 1998). By applying the TEF/TEQ

approach, the other highly toxic dioxins will be properly taken into account.

# 6 

# Aquatic Life Criteria

Revised Definition of Total PCBs for Aquatic Life Criteria

The aquatic life criteria for Polychlorinated Biphenyls (PCBs) in this compilation apply to

total PCBs. The definition of total PCBs is the sum of all homolog, all isomer, all congener, or

all Aroclor analyses. The aquatic life criteria contained in the previous publication of the

NRWQC (63 FR 68354, 12/10/1998) were based on total PCB concentrations, but the definition

of total PCBs only applied to the sum of seven particular Aroclors (1242, 1254, 1221, 1232,

1248, 1260 and 1016, CAS numbers 53469219, 11097691, 11104282, 11141165, 12672296,

11096825, and 12674112, respectively). This revision of the aquatic life criteria harmonizes the

total PCB definition with that used for EPA’s human health criteria for PCBs.

Saltwater Dissolved Oxygen (Cape Cod to Cape Hatteras)

This new compilation of NRWQC contains saltwater criteria for dissolved oxygen (D.O.).

EPA’s new water quality criteria are the result of a 10-year research effort to produce sufficient

information to support their development. The water quality criteria presented today represent

EPA's best estimates, based on the data available, of D.O. concentrations necessary to protect

aquatic life and uses associated with aquatic life.

EPA published saltwater criteria for dissolved oxygen because hypoxia (low dissolved

oxygen) is a significant problem for certain coastal waters that receive runoff containing nutrients

(e.g., nitrogen, phosphorous) and other oxygen demanding biological wastes. Excessive amounts

of nutrients in aquatic systems stimulate algal growth which can deplete available dissolved

oxygen required to maintain healthy fish and shellfish populations. EPA's Environmental

Monitoring and Assessment Program (EMAP) for the estuaries in the Virginian Province

(defined as Cape Cod to Cape Hatteras) has shown that 25% of the area of the Virginian Province

exhibits dissolved oxygen concentrations of less than 5 mg/L. For many fish and shellfish,

extended periods of D.O. below 5 mg/L can cause adverse effects to larval life stages. EMAP

also has generated field observations that correlate many of the biologically degraded benthic

areas with low dissolved oxygen in the lower water column. These two reports emphasize that

hypoxia is a major concern within the Virginian Province, among other coastal locations of the

United States.

The geographic scope of the saltwater dissolved oxygen water quality criteria are limited

to coastal saltwaters of the Virginian Province of the Atlantic coast of the United States (i.e.,

southern Cape Cod, MA, to Cape Hatteras, NC). However, the saltwater dissolved oxygen

criteria can be applied elsewhere if the species and data used to derive the criteria for the Virginia

Province are applicable to location-specific biological, physical, and water quality conditions.

EPA believes that the overall approach for deriving marine water quality criteria for D.O.

contained in Ambient Water Quality Criteria for Dissolved Oxygen (Saltwater): Cape Cod to

Cape Hatteras is applicable to regions outside the Virginian Province.

# 7 

# For additional information see: Ambient Water Quality Criteria for Dissolved Oxygen

(Saltwater): Cape Cod to Cape Hatteras (EPA-822R-00-012).

Freshwater Aquatic Life Criteria for Ammonia

This compilation includes EPA’s latest revision ( 1999 ) of the freshwater aquatic life

criteria for ammonia. The new water quality criteria reflect research and data since 1984,

including the pH and temperature relationship of the acute and chronic criteria and the averaging

period of the chronic criterion. The revised acute criterion for ammonia is now dependent on pH

and fish species, and the chronic criterion is dependent on pH and temperature. At lower

temperatures, the chronic criterion incorporates the presence or absence of early life stages of

fish. The temperature dependency results in a gradual increase in the criterion as temperature

decreases. At temperatures below 15 °C the criterion is more stringent, when early life stages of

fish are expected to be present. EPA's recommendations in the 1999 criteria represent a change

from both the 1984 chronic ammonia criterion, which was dependent mainly on pH, and from the

1998 ammonia criteria, in which the chronic criterion was dependent on pH and the presence of

early life stages of fish.

For additional information see: 1999 Update of Ambient Water Quality Criteria for

Ammonia (EPA-822-R-99-014).

Cadmium

EPA revised its aquatic life criteria for cadmium. A notice was published in the Federal

Register (65 FR 50201, 8/17/2000) announcing the availab ility of the peer review draft and

soliciting any significant scientific input from the public. EPA has addressed the peer review

comments and significant issues raised by the public. A notice of availability for the completed

document, entitled 2001 Update of Ambient Water Quality Criteria for Cadmium (EPA-822-R01-001) was published in the Federal Register on April 12, 2001 (66 FR18935).

Guidance on the Calculation of Hardness-Dependent Metals Criteria

Freshwater aquatic life criteria for certain metals are expressed as a function of hardness

because hardness can affect the toxicities of these metals. Hardness is used as a surrogate for a

number of water quality characteristics which affect the toxicity of metals. Increasing hardness

has the effect of decreasing the toxicity of metals. Water quality criteria to protect aquatic life

may be calculated at different concentrations of hardness measured in milligrams per liter (mg/L)

as calcium carbonate (CaCO

3 

# ).

Appendix B of this document presents the hardness-dependent equations for freshwater

metals criteria. The specific values in the table are calculated at a hardness of 100 mg/L (CaCO

3 

# )

for illustrative purposes only. The hardness equations included in this compilation were

developed based on results from laboratory toxicity tests that were conducted in fresh waters

encompassing a range of hardness values. Although the amount of data and the strength of the

# 8 

# relationship vary for different metals, almost all data for hardness and toxicity are in the 20 to

400 mg/L hardness range.

In the past, EPA recommended that when the hardness of fresh surface water is less than

25 mg/L, 304(a) criteria concentrations be calculated as if the hardness is 25 mg/L. Available

toxicity data in this range for copper, zinc and cadmium (EPA 440/5-84-031, EPA 440/5-87-

003,and EPA-822-R-01-001) are somewhat limited, and are quite limited for silver, lead,

chromium III and nickel (EPA 440/5-80-071, EPA 440/5-84-027,EPA 440/5-84-029 and EPA

440/5-86-004). Even fewer data are available below 20 mg/L hardness for copper, zinc and

cadmium and none are available for silver, lead, chromium III and nickel. EPA evaluated these

limited data, available in the current metals’ criteria documents, and determined that they are

inconclusive. Capping hardness at 25 mg/L without additional data or justification may result in

criteria that provide less protection than that intended by EPA’s Guidelines for Deriving

Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their

Uses (EPA 822/R-85-100) or “the Guidelines.” Therefore, EPA now recommends that hardness

not be capped at 25 mg/L, or any other hardness on the low end. If there is a state or tribal

regulatory requirement that hardness be capped at 25 mg/L, or if there are any situation-specific

questions about the applicability of the hardness-toxicity relationship, a Water Effect Ratio

(WER) procedure should be used to provide the level of protection intended by the Guidelines.

When an ambient hardness of less than 25 mg/L is used to establish criteria for lead or cadmium,

the hardness dependent Conversion Factor (CF) should not exceed one.

For hardness over 400 mg/L, EPA recommends two options: (1) calculate the criterion

using a default WER of 1.0 and using a hardness of 400 mg/L in the hardness equation; or (2)

calculate the criterion using a WER and the actual ambient hardness of the surface water in the

equation. The second option is expected to result in the level of protection intended in the

Guidelines whereas the first option is thought to result in an even more protective aquatic life

criterion. At high hardness there is an indication that hardness and related inorganic water

quality characteristics do not have as much of an effect on toxicity of metals as they do at lower

hardnesses. Related water quality characteristics do not correlate as well at higher hardnesses as

they do at lower hardnesses. There is also increased uncertainty in this range because very limited

data are available to clearly quantify the relationship between hardness and toxicity. Therefore, if

hardness is over 400 mg/L as CaCO

3 

# , EPA continues to recommend that a hardness of 400 mg/L

be used with a default WER of 1.0; alternatively, the WER and actual hardness of the surface

water may be used.

Where applicable water quality standards require the use of a default hardness (e.g., 25

mg/L) to calculate a criterion, states and authorized tribes should use the WER procedure to

adjust that criterion so that it provides the level of protection intended by the Guidelines. As the

WER is inherently a site-specific procedure, any WER developed for a given site would be

applicable only for that site unless its applicability at other sites is demonstrated. In any case,

states and authorized tribes electing to use the WER Guidance should ensure that their water

quality standards provide for them. Consistent with the “Performance-Based Approach”

discussed in detail in EPA’s recent modification of its implementing regulations at 40 CFR

# 9 

# 131.21 (See 65 FR 24641, April 27, 2000), EPA encourages states and authorized tribes to

identify all opportunities for adoption, and EPA approval of, such site-specific criteria. A

performance-based approach relies on the adoption of a standard method or process (e.g., WER

procedures) into state or tribal water quality standards, rather than adoption of a specific outcome

(e.g., a site-specific criterion). When such an approach is sufficiently detailed and has suitable

safeguards to ensure predictable, repeatable outcomes, EPA approval of the approach can serve

as approval of the outcomes as well.

National Guidance on the Applicability of Freshwater and Saltwater Criteria

EPA recommends that the aquatic life criteria in this compilation apply as follows:

(1) For water in which the salinity is equal to or less than 1 part per thousand 95% or

more of the time, the applicable criteria are the freshwater criteria.

(2) For water in which the salinity is equal to or greater than 10 parts per thousand

95% or more of the time, the applicable criteria are the saltwater criteria in

Column C; and

(3) For water in which the salinity is between 1 and 10 parts per thousand the

applicable criteria are the more stringent of the freshwater or saltwater criteria, as

described in items (1) and (2) of this section. However, an alternative freshwater

or saltwater criteria may be used if scientifically defensible information and data

demonstrate that on a site-specific basis the biology of the water body is

dominated by freshwater aquatic life and that freshwater criteria are more

appropriate; or conversely, the biology of the water body is dominated by

saltwater aquatic life and that saltwater criteria are more appropriate.

Nutrient Criteria

EPA recently developed section 304(a) water quality criteria for nutrients because

excessive levels of nutrients are a major cause of the nonattainment of designated uses and more

scientific information is needed to evaluate and address these conditions. Availability of these

nutrient criteria recommendations was announced in the Federal Register on January 9, 2001

(66 FR1671). EPA’s nutrient criteria w ill cover four major types of waterbodies: lakes and

reservoirs, rivers and streams, estuarine and coastal areas, and wetlands across 14 major

ecoregions of the United States. EPA’s section 304(a) criteria are intended to provide for the

protection and propagation of aquatic life and recreation. To support the development of the

nutrient criteria, EPA published Technical Guidance Manuals that describe a process for

assessing nutrient conditions in the four waterbody types. (For example See: Nutrient Criteria

Technical Guidance Manual: Lakes and Reservoirs , April 2000; Nutrient Criteria Technical

Guidance Manual; Rivers and Streams , July 2000; Nutrient Criteria Technical Guidance

Manual: Estuarine and Coastal Marine Waters , October 2001). This information is intended to

serve as a starting point for the states, authorized tribes and others to develop more refined

# 10 

# nutrient criteria, as appropriate, using EPA waterbody-specific technical guidance manuals and

other scientifically defensible approaches.

In cases where no new ecoregional nutrient criteria are available, the phosphate

phosphorus information presented in the Gold Book ( Quality Criteria for Water:1986 , EPA

440/5-86-001) may st ill be applicable. The phosphate phosphorus information in the Gold Book

address eutrophication in freshwater systems on a national basis without any consideration of

regional differences that may occur. The new ecoregional nutrient criteria recommendations

reflect regional differences in eutrophication for different water body types and ecological

conditions. The criteria in the compilation for elemental phosphorus is based on the toxic effects

of phosphorus to aquatic organisms and is not intended to prevent eutrophication.

VI Comments on the December 10, 1998 National Recommended Water Quality

Criteria Compilation

When the national recommended water quality criteria compilation was published in

1998, the Agency requested comment and observations on the compilation format and on the

revised criteria development process. No comments were received on the format or process.

Comments were, however, received on specific criteria and errors in formulas. The comments

stated that certain criteria did not reflect the latest scientific knowledge and also that some

criteria were derived based on data where an improper form of chemical was tested because of

bioavailability issues. The errors in the formulas have been corrected. EPA does not agree that

an improper form of the specified chemicals was tested.

VII Where Can I Find More Information About Water Quality Criteria and Water

Quality Standards?

For more information about water quality criteria and Water Quality Standards refer to

the following: Water Quality Standards Handbook (EPA 823-B94-005a); Advanced Notice of

Proposed Rule Making (ANPRM) , (63FR36742); Draft Strategy for Water Quality Standards and

Criteria: Strengthening the Foundation of Programs to Protect and Restore the Nation’s Water

(EPA-823-R-02-001, May 2002); Water Quality Criteria and Standards Plan

-- Priorities for the

Future (EPA 822-R-98-003); Guidelines and Methodologies Used in the Preparation of Health

Effects Assessment Chapters of the Consent Decree Water Criteria Documents (45FR79347);

Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health

(2000), EPA-822-B-00-004, October 2000); Guidelines for Deriving Numerical National Water

Quality Criteria for the Protection of Aquatic Organisms and Their Uses (EPA 822/R-85-100);

National Strategy for the Developm ent of Regional Nutrient Criteria (EPA 822-R-98-002); and

EPA Review and Approval of State and Tribal Water Quality Standards (65FR24641).

These publications may also be accessed through EPA’s National Service Center for

Environmental Publications (NSCEP, previously NCEPI) or on the Office of Science and

Technology’s Homepage ( www.epa.gov/OST).

# 11 

# VIII What Are the National Recommended Water Quality Criteria?

The following compilation and its associated footnotes and notes presents the EPA’s

latest national recommended water quality criteria.NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY TOXIC POLLUTANTS12Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1 Antimony74403605.6B640B65FR664432 Arsenic7440382 340A,D,K150A,D,K69A,D,bb36A,D,bb0.018C,M,S0.14C,M,S65FR3168257FR608483 Beryllium7440417Z65FR316824Cadmium74404392.0D,E,K,bb0.25D,E,K,bb40D,bb8.8D,bbZEPA-822-R-01-00165FR316825a Chromium (III)16065831 570D,E,K74D,E,KZ TotalEPA820/B-96-00165FR316825b Chromium (VI)18540299 16D,K11D,K1,100D,bb50D,bbZ Total65FR316826 Copper7440508 13D,E,K,cc9.0D,E,K,cc4.8D,cc,ff3.1D,cc,ff1,300 U65FR316827 Lead 7439921 65D,E,bb,gg2.5D,E,bb,gg210D,bb8.1D,bb65FR316828a8bMercuryMethylmercury7439976229679261.4D,K,hh0.77D,K,hh1.8D,ee,hh0.94D,ee,hh0.3 mg/kgJ62FR42160EPA823-R-01-0019 Nickel7440020 470D,E,K52D,E,K74D,bb8.2D,bb610B4,600B65FR3168210 Selenium7782492L,R,T5.0T290D,bb,dd71D,bb,dd170Z420062FR4216065FR3168265FR6644311 Silver 7440224 3.2D,E,G1.9D,G65FR3168212 Thallium74402801.7B6.3B65FR31682Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1313 Zinc7440666 120D,E,K120D,E,K90D,bb81D,bb7,400U26,000U65FR3168265FR6644314 Cyanide57125 22K,Q5.2K,Q1Q,bb1Q,bb700B220,000 B,HEPA820/B-96-00157FR6084815 Asbestos 1332214 7 millionfibers/LI57FR6084816 2,3,7,8-TCDD (Dioxin) 1746016 5.0E-9C5.1E-9C65FR6644317 Acrolein107028190 290 65FR6644318 Acrylonitrile1071310.051B,C0.25B,C65FR6644319 Benzene714322.2B,C51B,CIRIS 01/19/00&65FR6644320 Bromoform752524.3B,C140B,C65FR6644321 Carbon Tetrachloride 56235 0.23B,C1.6B,C65FR6644322 Chlorobenzene108907680B,Z,U,21,000B,H,U65FR3168223 Chlorodibromomethane 124481 0.40B,C13B,C65FR6644324 Chloroethane7500325 2-Chloroethylvinyl Ether 11075826 Chloroform676635.7C,P470C,P62FR4216027 Dichlorobromomethane752740.55B,C17B,C65FR66443Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1428 1,1-Dichloroethane7534329 1,2-Dichloroethane1070620.38B,C37B,C65FR6644330 1,1-Dichloroethylene753540.057C3.2C65FR6644331 1,2-Dichloropropane788750.50B,C15B,C65FR6644332 1,3-Dichloropropene54275610 1,700 57FR6084833 Ethylbenzene1004143,100B29,000B65FR3168234 Methyl Bromide7483947B1,500B65FR6644335 Methyl Chloride7487365FR3168236 Methylene Chloride750924.6B,C590B,C65FR6644337 1,1,2,2-Tetrachloroethane 793450.17B,C4.0B,C65FR6644338 Tetrachloroethylene 127184 0.69C3.3C65FR6644339 Toluene1088836,800B,Z200,000B65FR3168240 1,2-Trans-Dichloroethylene 156605700B,Z140,000B65FR3168241 1,1,1-Trichloroethane71556Z65FR3168242 1,1,2-Trichloroethane 79005 0.59B,C16B,C65FR6644343 Trichloroethylene790162.5C30C65FR6644344 Vinyl Chloride750142.0C530C57FR60848Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1545 2-Chlorophenol9557881B,U150B,U65FR6644346 2,4-Dichlorophenol12083277B,U290B,U65FR6644347 2,4-Dimethylphenol105679380B850B,U65FR6644348 2-Methyl-4,6-Dinitrophenol 53452113 280 65FR6644349 2,4-Dinitrophenol5128569B5,300B65FR6644350 2-Nitrophenol8875551 4-Nitrophenol10002752 3-Methyl-4-Chlorophenol 59507U U53 Pentachlorophenol87865 19F,K15F,K13bb7.9bb0.27B,C3.0B,C,H65FR3168265FR6644354 Phenol 108952 21,000B,U1,700,000B,U65FR6644355 2,4,6-Trichlorophenol880621.4B,C2.4B,C,U65FR6644356 Acenaphthene 83329 670B,U990B,U65FR6644357 Acenaphthylene20896858 Anthracene1201278,300B40,000B65FR6644359 Benzidine 928750.000086B,C0.00020B,C65FR6644360 Benzo(a)Anthracene565530.0038B,C0.018B,C65FR6644361 Benzo(a)Pyrene503280.0038B,C0.018B,C65FR66443Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1662 Benzo(b)Fluoranthene2059920.0038B,C0.018B,C65FR6644363 Benzo(ghi)Perylene19124264 Benzo(k)Fluoranthene2070890.0038B,C0.018B,C65FR6644365 Bis(2-Chloroethoxy)Methane11191166 Bis(2-Chloroethyl)Ether 111444 0.030B,C0.53B,C65FR6644367 Bis(2-Chloroisopropyl)Ether 1086011,400B65,000B65FR6644368 Bis(2-Ethylhexyl)PhthalateX1178171.2B,C2.2B,C65FR6644369 4-Bromophenyl Phenyl Ether 10155370 Butylbenzyl PhthalateW856871,500B1,900B65FR6644371 2-Chloronaphthalene 91587 1,000B1,600B65FR6644372 4-Chlorophenyl Phenyl Ether 700572373 Chrysene2180190.0038B,C0.018B,C65FR6644374 Dibenzo(a,h)Anthracene537030.0038B,C0.018B,C65FR6644375 1,2-Dichlorobenzene955012,700B17,000B65FR3168276 1,3-Dichlorobenzene 541731 320 960 65FR6644377 1,4-Dichlorobenzene 106467 400Z2,600 65FR3168278 3,3'-Dichlorobenzidine919410.021B,C0.028B,C65FR66443Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1779 Diethyl PhthalateW8466217,000B44,000B65FR6644380 Dimethyl PhthalateW131113270,000 1,100,000 65FR6644381 Di-n-Butyl PhthalateW847422,000B4,500B65FR6644382 2,4-Dinitrotoluene1211420.11C3.4C65FR6644383 2,6-Dinitrotoluene60620284 Di-n-Octyl Phthalate11784085 1,2-Diphenylhydrazine1226670.036B,C0.20B,C65FR6644386 Fluoranthene206440130B140B65FR6644387 Fluorene867371,100B5,300B65FR6644388 Hexachlorobenzene1187410.00028B,C0.00029B,C65FR6644389 Hexachlorobutadiene 87683 0.44B,C18B,C65FR6644390 Hexachlorocyclopentadiene 77474240U,Z17,000H,U57FR6084891 Hexachloroethane677211.4B,C3.3B,C65FR6644392 Ideno(1,2,3-cd)Pyrene1933950.0038B,C0.018B,C65FR6644393 Isophorone 78591 35B,C960B,C65FR6644394 Naphthalene9120395 Nitrobenzene9895317B690B,H,U65FR66443Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source1896 N-Nitrosodimethylamine627590.00069B,C3.0B,C65FR6644397 N-Nitrosodi-n-Propylamine 6216470.0050B,C0.51B,C65FR6644398 N-Nitrosodiphenylamine863063.3B,C6.0B,C65FR6644399 Phenanthrene85018100 Pyrene129000830B4,000B65FR66443101 1,2,4-Trichlorobenzene120821260 940 IRIS11/01/96102 Aldrin309002 3.0G1.3G0.000049 B,C 0.000050 B,C65FR3168265FR66443103 alpha-BHC3198460.0026B,C0.0049B,C65FR66443104 beta-BHC3198570.0091B,C0.017B,C65FR66443105 gamma-BHC (Lindane) 58899 0.95K0.16G0.019C0.063C65FR3168265FR66443106 delta-BHC319868107 Chlordane57749 2.4G0.0043G,aa0.09G0.004G,aa0.00080B,C0.00081B,C65FR3168265FR66443108 4,4'-DDT 50293 1.1G,ii0.001G,aa,ii0.13G,ii0.001G,aa,ii0.00022B,C0.00022B,C65FR3168265FR66443109 4,4'-DDE725590.00022B,C0.00022B,C65FR66443110 4,4'-DDD725480.00031B,C0.00031B,C65FR66443Priority PollutantCASNumberFreshwaterCMC CCC(μg/L)(μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism Only(μg/L) (μg/L)FR Cite/Source19111 Dieldrin60571 0.24K0.056K,O0.71G0.0019G,aa0.000052B,C0.000054B,C65FR3168265FR66443112 alpha-Endosulfan959988 0.22G,Y0.056G,Y0.034G,Y0.0087G,Y62B89B65FR3168265FR66443113 beta-Endosulfan33213659 0.22G,Y0.056G,Y0.034G,Y0.0087G,Y62B89B65FR3168265FR66443114 Endosulfan Sulfate1031078 62B89B65FR66443115 Endrin72208 0.086K0.036K,O0.037G0.0023G,aa0.76B0.81B,H65FR31682116 Endrin Aldehyde74219340.29B0.30B,H65FR66443117 Heptachlor76448 0.52G0.0038G,aa0.053G0.0036G,aa0.000079B,C0.000079B,C65FR3168265FR66443118 Heptachlor Epoxide1024573 0.52G,V0.0038G,V,aa0.053G,V0.0036G,V,aa0.000039B,C0.000039B,C65FR3168265FR66443119 Polychlorinated BiphenylsPCBs:0.014N,aa0.03N,aa0.000064 B,C,N 0.000064 B,C,N65FR3168265FR66443120 Toxaphene 8001352 0.73 0.0002aa0.21 0.0002aa0.00028B,C0.00028B,C65FR3168265FR66443Footnotes:A This recommended water quality criterion was derived from data for arsenic (III), but is applied here to total arsenic, whichmight imply that arsenic (III) andarsenic (V) are equally toxic to aquaticlife and that their toxicities are additive.In the arsenic criteria document (EPA 440/5-84-033, January 1985), SpeciesMean Acute Values are given for both arsenic (III) and arsenic (V) for five species and the ratios of the SMAVs foreach species range from 0.6 to 1.7.20Chronic values are available for both arsenic (III) and arsenic (V) for one species; for the fathead minnow, the chronic valuefor arsenic (V) is 0.29 times thechronic value for arsenic (III). No data are known to be available concerning whether the toxicities of the forms of arsenic to aquatic organisms are additive.B This criterion has been revised to reflect The Environmental Protection Agency’s q1* or RfD, as contained in the Integrated Risk Information System (IRIS)as of May 17, 2002. The fish tissue bioconcentration factor (BCF) from the 1980 Ambient Water Quality Criteria document was retained in each case.C This criterion is based on carcinogenicity of 10-6risk. Alternate risk levels may be obtained bymoving the decimal point (e.g., for a risk level of 10-5, movethe decimal point in the recommended criterion one place to the right).D Freshwater and saltwater criteria for metals are expressed in terms of the dissolved metal inthe water column. The recommended water quality criteriavalue was calculated by using the previous 304(a) aquatic life criteria expressed in terms of total recoverable metal, and multiplying it by a conversion factor(CF). The term "Conversion Factor" (CF) represents the recommended conversion factor for converting a metal criterion expressed as the total recoverablefraction in the water column to a criterion expressed as the dissolved fraction in the water column. (Conversion Factors for saltwater CCCs are not currentlyavailable. Conversion factors derived for saltwater CMCs have been used for both saltwater CMCs and CCCs). See "Office of Water Policy and TechnicalGuidance on Interpretation and Implementation of Aquatic Life Metals Criteria,” October 1, 1993, by Martha G. Prothro, ActingAssistant Administrator forWater, available from the Water Resource center, USEPA, 401 M St., SW, mail code RC4100, Washington, DC 20460; and 40CFR§131.36(b)(1).Conversion Factors applied in the table can be found in Appendix A to the Preamble- Conversion Factors for Dissolved Metals.E The freshwater criterion for this metal is expressed as a function of hardness (mg/L) in the water column. The value given here corresponds to a hardness of100 mg/L. Criteria values for other hardness may be calculated from the following: CMC (dissolved) = exp{mA[ln(hardness)]+ bA} (CF), or CCC(dissolved) = exp{mC[ln (hardness)]+ bC} (CF) and the parameters specified in Appendix B- Parameters for Calculating Freshwater Dissolved MetalsCriteria That Are Hardness-Dependent.F Freshwater aquatic life values for pentachlorophenol are expressed as a function of pH, and are calculated as follows: CMC =exp(1.005(pH)-4.869);CCC = exp(1.005(pH)-5.134). Values displayed in table correspond to a pH of 7.8.G This Criterion is based on 304(a) aquatic life criterion issued in 1980, and was issued in one of the following documents: Aldrin/Dieldrin (EPA 440/5-80-019), Chlordane (EPA 440/5-80-027), DDT (EPA 440/5-80-038), Endosulfan (EPA440/5-80-046), Endrin (EPA 440/5-80-047), Heptachlor (EPA 440/5-80-052), Hexachlorocyclohexane (EPA 440/5-80-054), Silver (EPA 440/5-80-071). The Minimum Data Requirements and derivation procedures weredifferent in the 1980 Guidelines than in the 1985 Guidelines. For example, a “CMC” derived using the 1980 Guidelines was derived to be used as aninstantaneous maximum. If assessment is to be done using an averaging period, the values given should be divided by 2 to obtain a value that is morecomparable to a CMC derived using the 1985 Guidelines.H No criterion for protection of human health from consumption of aquatic organisms excluding water was presented in the 1980 criteria document or in the1986 Quality Criteria for Water. Nevertheless, sufficient information was presented in the 1980 document to allow the calculation of a criterion, eventhough the results of such a calculation were not shown in the document.I This criterion for asbestos is the Maximum Contaminant Level (MCL) developed under the Safe Drinking Water Act (SDWA).JThisfishtissueresiduecriterionformethylmercuryisbasedonatotalfishconsumptionrateof0.0175kg/day.K This recommended criterion is based on a 304(a) aquatic life criterion that was issued in the1995 Updates: Water Quality Criteria Documents for theProtection ofAquatic Life in Ambient Water, (EPA-820-B-96-001, September 1996). This value was derived using the GLI Guidelines (60FR15393-15399,March 23, 1995; 40CFR132 Appendix A); the difference between the 1985 Guidelines and the GLI Guidelines are explained on page iv of the 1995 Updates.None of the decisions concerning the derivation of this criterion were affected by any considerations that are specific to theGreat Lakes.21L The CMC = 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and CMC1and CMC2 are 185.9 μg/l and 12.82 μg/l, respectively.M EPA is currently reassessing the criteria for arsenic.N This criterion applies to total pcbs, (e.g., the sum of all congener or all isomer or homolog or Aroclor analyses.)O The derivation of the CCC for this pollutant (Endrin) did not consider exposure through the diet, which is probably important for aquatic life occupyingupper trophic levels.P Although a new RfD is available in IRIS, the surface water criteria will not be revised until the National Primary Drinking Water Regulations: Stage 2Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) is completed, since public comment on the relative source contribution (RSC) forchloroform is anticipated.Q This recommended water quality criterion is expressed as μg free cyanide (as CN)/L.R This value for selenium was announced (61FR58444-58449, November 14, 1996) as a proposed GLI 303(c) aquatic life criterion. EPA is currently workingon this criterion and so this value might change substantially in the near future.S This recommended water quality criterion for arsenic refers to the inorganic form only.T This recommended water quality criterion for selenium is expressed in terms of total recoverable metal in the water column. It is scientifically acceptable touse the conversion factor (0.996- CMC or 0.922-CCC) that was used in the GLI to convert this to avalue that is expressed in terms of dissolved metal.U The organoleptic effect criterion is more stringent than the value for priority toxic pollutants.V This value was derived from data for heptachlor and the criteria document provides insufficient data to estimate the relativetoxicities of heptachlor andheptachlor epoxide.W Although EPA has not published a completed criteria document for butylbenzyl phthalate it is EPA’s understanding that sufficient data exist to allowcalculation of aquatic criteria. It is anticipated that industry intends to publish in the peer reviewed literature draft aquatic life criteria generated inaccordance with EPA Guidelines. EPA will review such criteria for possible issuance as national WQC.X There is a full set of aquatic life toxicitydata that show that DEHP is not toxic to aquatic organisms at or below its solubility limit.Y This value was derived from data for endosulfan and is most appropriately applied to the sum of alpha-endosulfan and beta-endosulfan.Z A more stringent MCL has been issued by EPA. Refer to drinking water regulations (40 CFR 141) or Safe Drinking Water Hotline (1-800-426-4791) forvalues.aa This criterion is based on a 304(a) aquatic life criterion issued in 1980 or 1986, and was issued in one of the following documents: Aldrin/Dieldrin (EPA440/5-80-019), Chlordane (EPA 440/5-80-027), DDT (EPA 440/5-80-038), Endrin (EPA 440/5-80-047), Heptachlor (EPA 440/5-80-052),Polychlorinatedbiphenyls (EPA 440/5-80-068), Toxaphene (EPA 440/5-86-006). ThisCCC is currently based on the Final ResidueValue (FRV) procedure. Since thepublication of the Great Lakes Aquatic Life Criteria Guidelines in 1995 (60FR15393-15399, March 23, 1995), the Agency no longer uses the Final ResidueValue procedure for deriving CCCs for new or revised304(a) aquatic life criteria. Therefore, the Agency anticipates that future revisions of thisCCC willnot be based on the FRV procedure.bb This water quality criterion is based on a304(a) aquatic life criterion that was derived using the 1985 Guidelines (Guidelines for Deriving NumericalNationalWater Quality Criteria for the Protection of Aquatic Organisms and Their Uses, PB85-227049, January 1985) and was issued in one of thefollowingcriteriadocuments:Arsenic(EPA440/5-84-033),Cadmium(EPA882-R-01-001),Chromium(EPA440/5-84-029),Copper (EPA440/5-84-031),Cyanide (EPA 440/5- 84-028), Lead (EPA 440/5-84-027), Nickel (EPA 440/5-86-004), Pentachlorophenol (EPA 440/5-86-009), Toxaphene, (EPA 440/5-86-006), Zinc (EPA 440/5-87- 003).22cc When the concentration of dissolved organic carbon is elevated, copper is substantially less toxic and use of Water-Effect Ratios might be appropriate.dd The selenium criteria document (EPA 440/5-87-006, September 1987) provides that if selenium is as toxic to saltwater fishes in the field as it is to freshwaterfishes in the field, the status of the fish community should be monitored wheneverthe concentration of selenium exceeds 5.0 μg/L in salt water because thesaltwater CCC does not take intoaccount uptake via the food chain.ee This recommended water quality criterion was derived on page 43 of the mercury criteria document (EPA440/5-84-026, January 1985). The saltwater CCCof 0.025 ug/L given on page 23 of the criteria document is based on the Final Residue Value procedure in the 1985 Guidelines.Since the publication of theGreat Lakes Aquatic Life Criteria Guidelines in 1995 (60FR15393-15399, March 23, 1995), the Agency no longer uses the Final Residue Value procedurefor deriving CCCs for new or revised304(a) aquatic life criteria.ff This recommended water quality criterion was derived inAmbient Water Quality Criteria Saltwater Copper Addendum(Draft, April 14, 1995) and waspromulgated in the Interim final National Toxics Rule (60FR22228-222237, May 4, 1995).gg EPA is actively working on this criterion and so this recommended water quality criterion may change substantially in the near future.hh This recommended water quality criterion wasderived from data for inorganic mercury (II), but isapplied here to total mercury. If a substantial portion ofthe mercury in the water column is methylmercury, this criterion will probably be under protective. In addition, even though inorganic mercury is convertedto methylmercury and methylmercury bioaccumulates to a greatextent, this criterion does not account for uptake via the food chain because sufficient datawere not available when the criterion was derived.ii This criterion applies to DDT and itsmetabolites (i.e., the total concentration of DDT and its metabolites should not exceedthis value).NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS23Non Priority PollutantCASNumberFreshwaterCMC CCC(μg/L) (μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism (μg/L) Only (μg/L)FRCite/Source1 Alkalinity--20000FGold Book2 Aluminum pH 6.5 - 9.0 7429905 750G,I87G,I,L53FR331783 Ammonia7664417 FRESHWATER CRITERIA ARE pH, Temperature and Life-stage DEPENDENT -- SEEDOCUMENTDSALTWATER CRITERIA ARE pH AND TEMPERATURE DEPENDENTEPA822-R-99-014EPA440/5-88-0044 Aesthetic Qualities--NARRATIVE STATEMENT-- SEE DOCUMENTGold Book5 Bacteria--FOR PRIMARY RECREATION AND SHELLFISH USES -- SEE DOCUMENT Gold Book6 Barium74403931,000AGoldBook7 Boron--NARRATIVE STATEMENT-- SEE DOCUMENTGold Book8 Chloride16887006 860,000G230,000G53FR190289 Chlorine 7782505 19 11 13 7.5CGold Book10 Chlorophenoxy Herbicide(2,4,5,-TP)9372110AGold Book11 Chlorophenoxy Herbicide(2,4-D)94757 100A,CGold Book12 Chloropyrifos2921882 0.083G0.041G0.011G0.0056GGold Book13 Color--NARRATIVE STATEMENT-- SEE DOCUMENTFGold Book14 Demeton80654830.1F0.1FGold Book15 Ether, Bis( Chloromethyl) 5428810.00010E, H0.00029E,H65FR66443Non Priority PollutantCASNumberFreshwaterCMC CCC(μg/L) (μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism (μg/L) Only (μg/L)FRCite/Source2416 Gases, Total Dissolved--NARRATIVE STATEMENT -- SEE DOCUMENTFGold Book17 Guthion865000.01F0.01FGold Book18 Hardness--NARRATIVE STATEMENT-- SEE DOCUMENTGold Book19 Hexachlorocyclo-hexaneTechnical3198680.0123 0.0414 Gold Book20 Iron74398961,000F300AGold Book21 Malathion1217550.1F0.1FGold Book22 Manganese743996550A,O100AGold Book23 Methoxychlor724350.03F0.03 F 100A,CGold Book24 Mirex23858550.001F0.001 FGold Book25 Nitrates1479755810,000AGold Book26 Nitrosamines--0.00081.24 Gold Book27 Dinitrophenols25550587695300 65FR6644328 Nitrosodibutylamine,N9241630.0063A,H0.22A,H65FR6644329 Nitrosodiethylamine,N551850.0008A,H1.24A,HGold Book30 Nitrosopyrrolidine,N9305520.016H34H65FR6644331 Oil and Grease--NARRATIVE STATEMENT -- SEE DOCUMENTFGold BookNon Priority PollutantCASNumberFreshwaterCMC CCC(μg/L) (μg/L)SaltwaterCMC CCC(μg/L)(μg/L)Human HealthFor Consumption of:Water + OrganismOrganism (μg/L) Only (μg/L)FRCite/Source2532 Oxygen, DissolvedFreshwaterOxygen, DissolvedSaltwater7782447 WARMWATER AND COLDWATER MATRIX -- SEE DOCUMENTNSALTWATER – SEE DOCUMENTGold BookEPA-822R-00-01233 Parathion56382 0.065 J 0.013JGold Book34 Pentachlorobenzene6089351.4E1.5E65FR6644335 pH--6.5 - 9F6.5 - 8.5F,K5 - 9Gold Book36 Phosphorus Elemental77231400.1F,KGold Book37 Nutrients-- See EPA’s Ecoregional criteria forTotal Phosphorus, Total Nitrogen, ChlorophyllaandWater Clarity (Secchi depth for lakes; turbidity for streams and rivers) (& Level IIIEcoregional criteria)P38 Solids Dissolved and Salinity --250,000AGold Book39 Solids Suspended andTurbidity--NARRATIVE STATEMENT -- SEE DOCUMENTFGold Book40 Sulfide-Hydrogen Sulfide 77830642.0F2.0FGold Book41 Tainting Substances--NARRATIVE STATEMENT-- SEE DOCUMENTGold Book42 Temperature--SPECIES DEPENDENT CRITERIA -- SEE DOCUMENTMGold Book43 Tetrachlorobenzene,1,2,4,5- 959430.97E1.1E65FR6644344 Tributyltin (TBT) -- 0.46Q0.063Q0.37Q0.010QEPA 822-F-00-00845Trichlorophenol,2,4,5-959541,800B,E3,600B,E65FR6644326Footnotes:A This human health criterion is the same as originally published in the Red Book which predates the1980 methodology and did not utilize the fish ingestionBCF approach. This same criterion value is now published in the Gold Book.B The organoleptic effect criterion is more stringent than the value presented in the non priority pollutants table.C A more stringent Maximum Contaminant Level (MCL) has been issued by EPA under the Safe Drinking Water Act. Refer to drinkingwater regulations40CFR141 or Safe Drinking Water Hotline (1-800-426-4791) for values.D According to the procedures described in theGuidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organismsand Their Uses, except possibly where a very sensitive species is important at a site, freshwater aquatic life should be protected if both conditions specifiedin Appendix C to the Preamble- Calculation of Freshwater Ammonia Criterion are satisfied.E This criterion has been revised to reflect EPA’s q1* or RfD, as contained in the Integrated Risk Information System (IRIS) asof May 17, 2002. The fishtissue bioconcentration factor (BCF) used to derive the original criterion was retained in each case.F The derivation of this value is presented in the Red Book (EPA440/9-76-023, July, 1976).G This value is based on a 304(a) aquatic life criterion that was derived using the 1985 Guidelines (Guidelines for Deriving Numerical National Water QualityCriteria for the Protection of Aquatic Organisms and Their Uses, PB85-227049, January 1985) and was issued in one of the following criteria documents:Aluminum (EPA 440/5-86-008); Chloride (EPA 440/5-88-001); Chloropyrifos (EPA 440/5-86-005).H This criterion is based on carcinogenicity of 10-6risk. Alternate risk levels may be obtained bymoving the decimal point (e.g., for a risk level of 10-5, movethe decimal point in the recommended criterion one place to the right).I This value for aluminum is expressed in termsof total recoverable metal in the water column.J This value is based on a 304(a)aquatic life criterion that was issued in the1995 Updates: Water Quality Criteria Documents for the Protection of AquaticLife in Ambient Water(EPA-820-B-96-001). This value was derived using the GLI Guidelines (60FR15393-15399, March 23, 1995; 40CFR132 AppendixA); the differences between the 1985 Guidelines and the GLI Guidelines are explained on page iv of the 1995 Updates. No decision concerning this criterionwas affected by any considerations that are specific to the Great Lakes.K According to page 181 of the Red Book:For open ocean waters where the depth is substantially greater than theeuphotic zone, the pH shouldnot be changed more than 0.2 units from thenaturally occurring variation or any case outside the range of 6.5 to 8.5. For shallow, highly productive coastal and estuarine areas where naturallyoccurring pH variations approach the lethal limits of some species, changes in pH should be avoided but in any case should notexceed the limitsestablished for fresh water, i.e., 6.5-9.0.L There are three major reasons why the use of Water-Effect Ratios might be appropriate. (1) The value of 87 μg/l is based on atoxicity test with the stripedbass in water with pH= 6.5-6.6 and hardness <10 mg/L. Data in“Aluminum Water-Effect Ratio for the 3M Plant Effluent Discharge, Middleway, WestVirginia” (May 1994) indicate that aluminum is substantially less toxic at higher pH and hardness, but the effects of pH and hardness are not well quantifiedat this time. (2) In tests with the brook trout at low pH and hardness, effects increased with increasing concentrations of total aluminum even though theconcentration of dissolved aluminum was constant, indicating that total recoverable is a more appropriate measurement than dissolved, at least whenparticulate aluminum is primarily aluminum hydroxide particles. In surface waters, however, the total recoverable procedure might measure aluminumassociated with clay particles, which might be less toxic than aluminum associated with aluminum hydroxide. (3) EPA is aware of field data indicating thatmany high quality waters in the U.S. contain more than 87 μg aluminum/L, when either total recoverable or dissolved is measured.M U.S. EPA. 1973. Water Quality Criteria1972. EPA-R3-73-033. National Technical Information Service, Springfield, VA.; U.S. EPA. 1977. TemperatureCriteria for Freshwater Fish: Protocol and Procedures. EPA-600/3-77-061. National Technical Information Service, Springfield,VA.27N U.S. EPA. 1986. Ambient Water Quality Criteria for Dissolved Oxygen. EPA440/5-86-003. National Technical Information Service, Springfield, VA.O This criterion for manganese is not based on toxic effects, but rather is intended to minimize objectionable qualities suchas laundry stains andobjectionable tastes in beverages.P Lakes and Reservoirs in Nutrient Ecoregion: II EPA 822-B-00-007,III EPA822-B-01-008, IV EPA 822-B-01-009, V EPA 822-B-01-010, VI EPA 822-B00-008 , VII EPA 822-B-00-009, VIII EPA822-B-01-015, IX EPA 822-B-00-011, XI EPA 822-B-00-012, XII EPA 822-B-00-013, XIII EPA822-B-00-014,XIV EPA 822-B-01-011; Rivers and Streams in Nutrient Ecoregion: I EPA 822-B-01-012, II EPA 822-B-00-015,III EPA822-B-00-016, IV EPA 822-B-01-013, V EPA 822-B-01-014, VI EPA 822-B-00-017, VII EPA 822-B-00-018, VIII EPA822-B-01-015, IX EPA 822-B-00-019, X EPA 822-B-01-016, XIEPA 822-B-00-020, XII EPA 822-B-00-021, XIV EPA 822-B-00-022; and Wetlands in Nutrient Ecoregion XIII EPA822-B-00-023.Q EPA announced the availability of a draft updated tributyltin (TBT) document on August 7,1997 (62FR42554). The Agency has reevaluated this documentand anticipates releasing an updated document for public comment in the near future.28NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR ORGANOLEPTIC EFFECTSPollutantCAS NumberOrganoleptic Effect Criteria(μg/L) FR Cite/Source1 Acenaphthene8332920Gold Book2 Monochlorobenzene10890720Gold Book3 3-Chlorophenol--0.1Gold Book4 4-Chlorophenol1064890.1Gold Book5 2,3-Dichlorophenol--0.04Gold Book6 2,5-Dichlorophenol--0.5Gold Book7 2,6-Dichlorophenol--0.2Gold Book8 3,4-Dichlorophenol--0.3Gold Book9 2,4,5-Trichlorophenol959541Gold Book10 2,4,6-Trichloropehnol880622Gold Book11 2,3,4,6-Tetrachlorophenol--1Gold Book12 2-Methyl-4-Chlorophenol--1,800Gold Book13 3-Methyl-4-Chlorophenol595073,000Gold Book14 3-Methyl-6-Chlorophenol--20Gold Book15 2-Chlorophenol955780.1Gold Book16 Copper74405081,000Gold Book17 2,4-Dichlorophenol1208320.3Gold Book18 2,4-Dimethylpehnol105679400Gold Book19 Hexachlorocyclopentadiene774741Gold Book20 Nitrobenzene9895330Gold BookPollutantCAS NumberOrganoleptic Effect Criteria(μg/L) FR Cite/Source2921 Pentachlorophenol8786530Gold Book22 Phenol108952300Gold Book23 Zinc74406665,00045 FR79341General Notes:1. These criteria are based on organoleptic (taste and odor) effects.Because of variations in chemical nomenclature systems, this listing of pollutants does notduplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service (CAS) registry numbers,which provide a uniqueidentification for each chemical.NATIONAL RECOMMENDED WATER QUALITY CRITERIAAdditional Notes:1. Criteria Maximum Concentration and Criterion Continuous ConcentrationThe Criteria Maximum Concentration (CMC) is an estimate of the highest concentration of a material in surface water to whichan aquatic community can beexposed briefly without resulting in an unacceptable effect. The Criterion Continuous Concentration (CCC) is an estimate of the highest concentration of amaterial in surface water to which an aquatic community can be exposed indefinitelywithout resulting in an unacceptable effect. The CMC and CCC are justtwo of the six parts of an aquatic life criterion; the other four parts are the acute averaging period, chronic averaging period, acute frequency of allowedexceedence, and chronic frequency of allowed exceedence. Because304(a) aquatic life criteria are national guidance, they are intended to be protective of thevast majority of the aquaticcommunities in the United States.2. Criteria Recommendations for Priority Pollutants, Non Priority Pollutants and Organoleptic EffectsThis compilation lists all priority toxic pollutants and some non priority toxic pollutants, and both human health effect and organoleptic effect criteria issuedpursuant to CWA §304(a). Blank spaces indicate that EPA has no CWA §304(a) criteria recommendations. For a number ofnon-priority toxic pollutants notlisted, CWA §304(a) “water + organism” human health criteria are not available, but EPA has published MCLsunder the SDWA that may be used inestablishing water quality standards to protect water supply designated uses. Because of variations in chemical nomenclature systems, this listing of toxicpollutants does not duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service CASregistry numbers, whichprovide a unique identification for each chemical.3. Human Health RiskThe human health criteria for the priority and non priority pollutants are based on carcinogenicity of 10-6risk. Alternate risk levels may be obtained bymoving the decimal point (e.g., for a risk level of 10-5, move the decimal point in the recommended criterion one place to the right).4. Water Quality Criteria published pursuant to Section 304(a) or Section 303(c) of the CWAMany of the values in the compilation were published in the California Toxics Rule. Although such values were published pursuant to Section 303(c) of theCWA, they represent the Agency’s most recent calculation of water quality criteria and are thus the Agency’s304(a) criteria.305. Calculation of Dissolved Metals CriteriaThe 304(a) criteria for metals, shown as dissolved metals, are calculated in one of two ways. For freshwater metals criteria that are hardness-dependent, thedissolved metal criteria were calculated using a hardness of 100 mg/l as CaCO3for illustrative purposes only. Saltwater and freshwater metals’ criteria that arenot hardness-dependent are calculated by multiplying the total recoverable criteria before rounding by the appropriate conversion factors. The final dissolvedmetals’ criteria in the table are rounded to two significant figures. Information regarding the calculation of hardness dependent conversion factors are includedin the footnotes.6. Maximum Contaminant LevelsThe compilation includes footnotes for pollutants with Maximum Contaminant Levels (MCLs) more stringent than the recommended water quality criteria inthe compilation. MCLs for these pollutants are not included in the compilation, but can be found in the appropriate drinking water regulations (40 CFR 141.11-16 and 141.60-63), or can beaccessed through the Safe Drinking Water Hotline (800-426-4791) or the Internet(http://www.epa.gov/waterscience/drinking/standards/dwstandards.pdf).7. Organoleptic EffectsThe compilation contains 304(a) criteria for pollutants with toxicity-based criteria as well asnon-toxicity based criteria. The basis for the non-toxicity basedcriteria are organoleptic effects (e.g., taste and odor) which would make water and edible aquatic life unpalatable but not toxic to humans. The table includescriteria for organoleptic effects for 23 pollutants. Pollutants with organoleptic effect criteria more stringent than the criteria based on toxicity (e.g., included inboth the priority and non-priority pollutant tables) are footnoted as such.8. Gold BookThe “Gold Book” is Quality Criteria for Water:1986. EPA 440/5-86-001.9. Correction of Chemical Abstract Services NumberThe Chemical Abstract Services number (CAS) for Bis(2-Chlorisoprpyl) Ether, has been revised in IRIS and in the table. The correct CAS number for thischemical is 108-60-1. The previous CAS number for this pollutant was 39638-32-9.10. Contaminants with BlanksEPA has not calculated criteria for contaminants with blanks. However, permit authorities should address these contaminants inNPDES permit actions usingthe States’ existing narrative criteria for toxics.11. Specific Chemical CalculationsA. SeleniumAquatic LifeThis compilation contains aquatic life criteria for selenium that are the same as those published in the proposed CTR. In theCTR, EPA proposed an acutecriterion for selenium based on the criterion proposed for seleniumin the Water Quality Guidancefor the Great Lakes System (61 FR 58444). The GLI andCTR proposals take into account data showing that selenium’s two prevalent oxidation states in water, selenite and selenate, present differing potentials foraquatic toxicity, as well as new data indicating that various forms of selenium are additive. The new approach produces a different selenium acute criterionconcentration, or CMC, depending upon the relative proportions of selenite, selenate, and other forms of selenium that are present.EPA is currently undertaking a reassessment of selenium, and expects the304(a) criteria for selenium will be revised based on the final reassessment(63FR26186). However, until such time as revised water quality criteria for selenium are published by the Agency, the recommended water quality criteria inthis compilation are EPA’s current 304(a) criteria.31Appendices:Appendix A - Conversion Factors for Dissolved MetalsMetalConversion Factorfreshwater CMCConversion Factorfreshwater CCCConversion Factorsaltwater CMCConversion Factorsaltwater CCC1Arsenic1.0001.0001.0001.000Cadmium1.136672-[(lnhardness)(0.041838)]1.101672-[(lnhardness)(0.041838)]0.9940.994Chromium III0.3160.860----Chromium VI0.9820.9620.9930.993Copper0.9600.9600.830.83Lead1.46203-[(lnhardness)(0.145712)]1.46203-[(lnhardness)(0.145712)]0.9510.951Mercury0.850.850.850.85Nickel0.9980.9970.9900.990Selenium----0.9980.998Silver0.85--0.85--Zinc0.9780.9860.9460.94632Appendix B - Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-DependentChemical mAbAmCbCFreshwater Conversion Factors (CF)CMCCCCCadmium 1.0166 -3.924 0.7409 -4.7191.136672-[(lnhardness)(0.041838)]1.101672-[(lnhardness)(0.041838)]Chromium III 0.8190 3.7256 0.8190 0.68480.3160.860Copper0.9422 -1.700 0.8545 -1.7020.9600.960Lead1.273 -1.460 1.273 -4.7051.46203-[(lnhardness)(0.145712)]1.46203-[(lnhardness)(0.145712)]Nickel0.8460 2.255 0.8460 0.05840.9980.997Silver1.72 -6.59 -- --0.85--Zinc0.8473 0.884 0.8473 0.8840.9780.986Hardness-dependant metals’ criteria may be calculated from the following:CMC (dissolved) = exp{mA[ln(hardness)]+ bA} (CF)CCC (dissolved) = exp{mC[ln(hardness)]+ bC} (CF)33Appendix C - Calculation of Freshwater Ammonia Criterion1. The one-hour average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three yearson the average,the CMC (acute criterion) calculated using the following equations.Where salmonid fish are present:0.275 39.0CMC = -------------------- + ------------------------1 + 107.204-pH1 + 10pH-7.204Or where salmonid fish are not present:0.411 58.4CMC = -------------------- + ------------------------1 + 107.204-pH1 + 10pH-7.2042A The thirty-day average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three years on theaverage, the CCC (chronic criterion) calculated using the following equations.When fish early life stages are present:0.0577 2.487CCC =‰-------------------- + ------------------------CMIN (2.85, 1.45@100.028@(25-T))1 + 107.688-pH1 + 10pH-7.688When fish early life stages are absent:0.0577 2.487CCC =‰-------------------- + ------------------------C1.45@100.028@(25-MAX (T,7))1 + 107.688-pH1 + 10pH-7.6882B. In addition, the highest four-day average within the 30-day period should not exceed 2.5 times the CCC.