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
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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.
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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
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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
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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 based 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.
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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
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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
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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 availability 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.
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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.
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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 availability 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 (CaCO3).

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 (CaCO3)

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
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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 CaCO3, 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
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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 will 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 still 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 Development 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 POLLUTAN

12

Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

1 Antimony 7440360 5.6 B 

2 Arsenic 7440382 340 A,D,K 150 A,D,K 69 A,D,bb 36 A,D,bb

0.018 C,M,S 

3 Beryllium 7440417 Z 4 Cadmium 7440439 2.0 D,E,K,bb 0.25

D,E,K,bb 40

D,bb 8.8 D,bb Z 

5a Chromium (III) 16065831 570 D,E,K 74 D,E,K Z Total 5b Chromium (VI) 18540299 16 D,K 11 D,K 1,100 D,bb 50 D,bb Z Total 6 Copper 7440508 13 D,E,K,cc 9.0 D,E,K,cc 4.8 D,cc,ff 3.1 D,cc,ff 1,300 U 7 Lead 7439921 65 D,E,bb,gg 2.5 D,E,bb,gg 210 D,bb 8.1 D,bb 8a8b

MercuryMethylmercury 

7439976

22967926

1.4 D,K,hh 0.77 D,K,hh 1.8 D,ee,hh 0.94 D,ee,hh 

9 Nickel 7440020 470 D,E,K 52 D,E,K 74 D,bb 8.2 D,bb 610 B 

10 Selenium 7782492 L,R,T

5.0 T 290 D,bb,dd 71 D,bb,dd

170 Z 

11 Silver 7440224 3.2 D,E,G 1.9 D,G 

12 Thallium 7440280 1.7 B 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

13

13 Zinc 7440666 120 D,E,K 120 D,E,K 90 D,bb 81 D,bb

7,400 U 

14 Cyanide 57125 22 K,Q 5.2 K,Q

1 Q,bb 1 Q,bb 700 B 

15 Asbestos 1332214 7 million

fibers/L I

16 2,3,7,8-TCDD (Dioxin) 1746016 5.0E-9 C 17 Acrolein 107028 190 18 Acrylonitrile 107131 0.051 B,C 19 Benzene 71432 2.2 B,C 

20 Bromoform 75252 4.3 B,C 

21 Carbon Tetrachloride 56235 0.23 B,C 22 Chlorobenzene 108907 680 B,Z,U, 23 Chlorodibromomethane 124481 0.40 B,C 24 Chloroethane 7500325 2-Chloroethylvinyl Ether 11075826 Chloroform 67663 5.7 C,P 27 Dichlorobromomethane 75274 0.55 B,C 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

14

28 1,1-Dichloroethane 7534329 1,2-Dichloroethane 107062 0.38 B,C 

30 1,1-Dichloroethylene 75354 0.057 C 31 1,2-Dichloropropane 78875 0.50 B,C 32 1,3-Dichloropropene 542756 10 33 Ethylbenzene 100414 3,100 B 34 Methyl Bromide 74839 47 B 35 Methyl Chloride 74873 36 Methylene Chloride 75092 4.6 B,C 37 1,1,2,2-Tetrachloroethane 79345 0.17 B,C 38 Tetrachloroethylene 127184 0.69 C 39 Toluene 108883 6,800 B,Z 40 1,2-Trans-Dichloroethylene 156605 700 B,Z 41 1,1,1-Trichloroethane 71556 Z 42 1,1,2-Trichloroethane 79005 0.59 B,C 43 Trichloroethylene 79016 2.5 C 44 Vinyl Chloride 75014 2.0 C 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

15

45 2-Chlorophenol 95578 81 B,U 

46 2,4-Dichlorophenol 120832 77 B,U 47 2,4-Dimethylphenol 105679 380 B 48 2-Methyl-4,6-Dinitrophenol 534521 13 49 2,4-Dinitrophenol 51285 69 B 50 2-Nitrophenol 8875551 4-Nitrophenol 10002752 3-Methyl-4-Chlorophenol 59507 U 

53 Pentachlorophenol 87865 19 F,K 15 F,K 13 bb 7.9 bb

0.27 B,C 

54 Phenol 108952 21,000 B,U 55 2,4,6-Trichlorophenol 88062 1.4 B,C 56 Acenaphthene 83329 670 B,U 57 Acenaphthylene 20896858 Anthracene 120127 8,300 B 59 Benzidine 92875 0.000086 B,C 60 Benzo(a)Anthracene 56553 0.0038 B,C 61 Benzo(a)Pyrene 50328 0.0038 B,C 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

16

62 Benzo(b)Fluoranthene 205992 0.0038 B,C 

63 Benzo(ghi)Perylene 19124264 Benzo(k)Fluoranthene 207089 0.0038 B,C 65 Bis(2-

Chloroethoxy)Methane

111911

66 Bis(2-Chloroethyl)Ether 111444 0.030 B,C 

67 Bis(2-Chloroisopropyl)Ether 108601 1,400 B 68 Bis(2-Ethylhexyl)PhthalateX 117817 1.2 B,C 69 4-Bromophenyl Phenyl Ether 10155370 Butylbenzyl PhthalateW 85687 1,500 B 71 2-Chloronaphthalene 91587 1,000 B 72 4-Chlorophenyl Phenyl Ether 700572373 Chrysene 218019 0.0038 B,C 74 Dibenzo(a,h)Anthracene 53703 0.0038 B,C 75 1,2-Dichlorobenzene 95501 2,700 B 76 1,3-Dichlorobenzene 541731 320 77 1,4-Dichlorobenzene 106467 400 Z 

78 3,3'-Dichlorobenzidine 91941 0.021 B,C 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

17

79 Diethyl PhthalateW 84662 17,000 B 

80 Dimethyl PhthalateW 131113 270,000 

81 Di-n-Butyl PhthalateW 84742 2,000 B 

82 2,4-Dinitrotoluene 121142 0.11 C 83 2,6-Dinitrotoluene 60620284 Di-n-Octyl Phthalate 11784085 1,2-Diphenylhydrazine 122667 0.036 B,C 86 Fluoranthene 206440 130 B 87 Fluorene 86737 1,100 B 88 Hexachlorobenzene 118741 0.00028 B,C 89 Hexachlorobutadiene 87683 0.44 B,C 90 Hexachlorocyclopentadiene 77474 240 U,Z 91 Hexachloroethane 67721 1.4 B,C 92 Ideno(1,2,3-cd)Pyrene 193395 0.0038 B,C 93 Isophorone 78591 35 B,C 

94 Naphthalene 9120395 Nitrobenzene 98953 17 B 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

18

96 N-Nitrosodimethylamine 62759 0.00069 B,C 

97 N-Nitrosodi-n-Propylamine 621647 0.0050 B,C 98 N-Nitrosodiphenylamine 86306 3.3 B,C 99 Phenanthrene 85018100 Pyrene 129000 830 B 101 1,2,4-Trichlorobenzene 120821 260 102 Aldrin 309002 3.0 G 1.3 G

0.000049 B,C 

103 alpha-BHC 319846 0.0026 B,C 104 beta-BHC 319857 0.0091 B,C 105 gamma-BHC (Lindane) 58899 0.95 K 0.16 G

0.019 C 

106 delta-BHC 319868107 Chlordane 57749 2.4 G 0.0043 G,aa 0.09 G 0.004 G,aa

0.00080 B,C 

108 4,4'-DDT 50293 1.1 G,ii 0.001 G,aa,ii 0.13 G,ii 0.001 G,aa,ii

0.00022 B,C 

109 4,4'-DDE 72559 0.00022 B,C 110 4,4'-DDD 72548 0.00031 B,C 
Priority Pollutant

CASNumber

 Freshwater

 CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

 Human H For ConsumWater + OOrganism  (μg/L) 

19

111 Dieldrin 60571 0.24 K 0.056 K,O 0.71 G 0.0019 G,aa

0.000052 B,C 

112 alpha-Endosulfan 959988 0.22 G,Y 0.056 G,Y 0.034 G,Y 0.0087 G,Y

62 B 

113 beta-Endosulfan 33213659 0.22 G,Y 0.056 G,Y 0.034 G,Y 0.0087 G,Y

62 B 

114 Endosulfan Sulfate 1031078 62 B 115 Endrin 72208 0.086 K 0.036 K,O 0.037 G 0.0023 G,aa 0.76 B 116 Endrin Aldehyde 7421934 0.29 B 117 Heptachlor 76448 0.52 G 0.0038 G,aa 0.053 G 0.0036 G,aa

0.000079 B,C 

118 Heptachlor Epoxide 1024573 0.52 G,V 0.0038 G,V,aa 0.053 G,V 0.0036 G,V,aa

0.000039 B,C 

119 Polychlorinated Biphenyls

PCBs:

0.014 N,aa 0.03 N,aa

0.000064 B,C,N 

120 Toxaphene 8001352 0.73 0.0002 aa 0.21 0.0002 aa

0.00028 B,C 

Footnotes:A This recommended water quality criterion was derived from data for arsenic (III), but is applied here to total arsenic, which might imply 

arsenic (V) are equally toxic to aquatic life and that their toxicities are additive. In the arsenic criteria document (EPA 440/5-84-033, J

Mean Acute Values are given for both arsenic (III) and arsenic (V) for five species and the ratios of the SMAVs for each species range f
20

Chronic values are available for both arsenic (III) and arsenic (V) for one species; for the fathead minnow, the chronic value for arsenic chronic value for arsenic (III). No data are known to be available concerning whether the toxicities of the forms of arsenic to aquatic org

B This criterion has been revised to reflect The Environmental Protection Agency’s q1* or RfD, as contained in the Integrated Risk Inform

as of May 17, 2002. The fish tissue bioconcentration factor (BCF) from the 1980 Ambient Water Quality Criteria document was retaine

C This criterion is based on carcinogenicity of 10-6 risk. Alternate risk levels may be obtained by moving the decimal point (e.g., for a risk 

 the 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 in the water column. The recommended water 

 value was calculated by using the previous 304(a) aquatic life criteria expressed in terms of total recoverable metal, and multiplying it b (CF). The term "Conversion Factor" (CF) represents the recommended conversion factor for converting a metal criterion expressed as fraction in the water column to a criterion expressed as the dissolved fraction in the water column. (Conversion Factors for saltwater CCavailable. Conversion factors derived for saltwater CMCs have been used for both saltwater CMCs and CCCs). See "Office of Water PGuidance on Interpretation and Implementation of Aquatic Life Metals Criteria,” October 1, 1993, by Martha G. Prothro, Acting AssistWater, available from the Water Resource center, USEPA, 401 M St., SW, mail code RC4100, Washington, DC 20460; and 40CFR§13Conversion 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 correspo

100 mg/L. Criteria values for other hardness may be calculated from the following: CMC (dissolved) = exp{mA [ln(hardness)]+ bA} (C

(dissolved) = exp{mC [ln (hardness)]+ bC} (CF) and the parameters specified in Appendix B- Parameters for Calculating Freshwater Di

Criteria 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(1.00

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/Dieldri

019), Chlordane (EPA 440/5-80-027), DDT (EPA 440/5-80-038), Endosulfan (EPA 440/5-80-046), Endrin (EPA 440/5-80-047), He

80-052), Hexachlorocyclohexane (EPA 440/5-80-054), Silver (EPA 440/5-80-071). The Minimum Data Requirements and derivation 

different in the 1980 Guidelines than in the 1985 Guidelines. For example, a “CMC” derived using the 1980 Guidelines was derived to instantaneous maximum. If assessment is to be done using an averaging period, the values given should be divided by 2 to obtain a valucomparable 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 d

1986 Quality Criteria for Water. Nevertheless, sufficient information was presented in the 1980 document to allow the calculation of a 

though 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).J This fish tissue residue criterion for methylmercury is based on a total fish consumption rate of 0.0175 kg/day.

K This recommended criterion is based on a 304(a) aquatic life criterion that was issued in the 1995 Updates: Water Quality Criteria Doc

Protection of Aquatic Life in Ambient Water, (EPA-820-B-96-001, September 1996). This value was derived using the GLI Guideline

March 23, 1995; 40CFR132 Appendix A); the difference between the 1985 Guidelines and the GLI Guidelines are explained on page iv None of the decisions concerning the derivation of this criterion were affected by any considerations that are specific to the Great Lakes. 
21

L The CMC = 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, resp

and 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  upper 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 Regula

Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) is completed, since public comment on the relative source contribution chloroform 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 

on 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 scienti

use the conversion factor (0.996- CMC or 0.922- CCC) that was used in the GLI to convert this to a value that is expressed in terms of 

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 relative toxicities of 

heptachlor epoxide.

W Although EPA has not published a completed criteria document for butylbenzyl phthalate it is EPA’s understanding that sufficient data e

calculation of aquatic criteria. It is anticipated that industry intends to publish in the peer reviewed literature draft aquatic life criteria geaccordance with EPA Guidelines. EPA will review such criteria for possible issuance as national WQC.

X There is a full set of aquatic life toxicity data 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 (1-8

 values.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: Aldr

440/5-80-019), Chlordane (EPA 440/5-80-027), DDT (EPA 440/5-80-038), Endrin (EPA 440/5-80-047), Heptachlor (EPA 440/5-80-biphenyls (EPA 440/5-80-068), Toxaphene (EPA 440/5-86-006). This CCC is currently based on the Final Residue Value (FRV) proce

publication of the Great Lakes Aquatic Life Criteria Guidelines in 1995 (60FR15393-15399, March 23, 1995), the Agency no longer usValue procedure for deriving CCCs for new or revised 304(a) aquatic life criteria. Therefore, the Agency anticipates that future revision

not be based on the FRV procedure. 

bb This water quality criterion is based on a 304(a) aquatic life criterion that was derived using the 1985 Guidelines (Guidelines for Derivi

National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses, PB85-227049, January 1985) and was issuefollowing criteria documents: Arsenic (EPA 440/5-84-033), Cadmium (EPA 882-R-01-001), Chromium (EPA 440/5-84-029), Copper Cyanide (EPA 440/5- 84-028), Lead (EPA 440/5-84-027), Nickel (EPA 440/5-86-004), Pentachlorophenol (EPA 440/5-86-009), Tox

86-006), Zinc (EPA 440/5-87- 003). 
22

cc When the concentration of dissolved organic carbon is elevated, copper is substantially less toxic and use of Water-Effect Ratios might bdd The selenium criteria document (EPA 440/5-87-006, September 1987) provides that if selenium is as toxic to saltwater fishes in the fiel

fishes in the field, the status of the fish community should be monitored whenever the concentration of selenium exceeds 5.0 μg/L in salt 

saltwater CCC does not take into account uptake via the food chain.

ee This recommended water quality criterion was derived on page 43 of the mercury criteria document (EPA 440/5-84-026, January 1985)

of 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 thGreat Lakes Aquatic Life Criteria Guidelines in 1995 (60FR15393-15399, March 23, 1995), the Agency no longer uses the Final Residfor deriving CCCs for new or revised 304(a) aquatic life criteria.

ff This recommended water quality criterion was derived in Ambient Water Quality Criteria Saltwater Copper Addendum (Draft, April 14

promulgated 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 was derived from data for inorganic mercury (II), but is applied here to total mercury. If a sub

the mercury in the water column is methylmercury, this criterion will probably be under protective. In addition, even though inorganic m

to methylmercury and methylmercury bioaccumulates to a great extent, this criterion does not account for uptake via the food chain beca

were not available when the criterion was derived.

ii This criterion applies to DDT and its metabolites (i.e., the total concentration of DDT and its metabolites should not exceed this value).
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANT

23

Non Priority Pollutant

CASNumber

Freshwater

CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

Human Health

 For Consumption of

 Water + OrganismOrganism (μg/L) Only (μ

1 Alkalinity -- 20000 F 

2 Aluminum pH 6.5 - 9.0 7429905 750 G,I 87 G,I,L 

3 Ammonia 7664417 FRESHWATER CRITERIA ARE pH, Temperature and Life-stage DEPENDENT -- S

DOCUMENT 

D

SALTWATER CRITERIA ARE pH AND TEMPERATURE DEPENDENT

4 Aesthetic Qualities -- NARRATIVE STATEMENT-- SEE DOCUMENT 5 Bacteria -- FOR PRIMARY RECREATION AND SHELLFISH USES -- SEE DOCUMENT 6 Barium 7440393 1,000 

A 

7 Boron -- NARRATIVE STATEMENT-- SEE DOCUMENT 8 Chloride 16887006 860,000 

G 230,000 

G 

9 Chlorine 7782505 19 11 13 7.5 C 

10 Chlorophenoxy Herbicide

(2,4,5,-TP)

93721 10 A 

11 Chlorophenoxy Herbicide

(2,4-D)

94757 100 A,C 

12 Chloropyrifos 2921882 0.083 

G 0.041 

G 0.011 

G 0.0056 

G 

13 Color -- NARRATIVE STATEMENT-- SEE DOCUMENT F 14 Demeton 8065483 0.1 F 0.1 F 15 Ether, Bis( Chloromethyl) 542881 0.00010 E, H 0.00029 
Non Priority Pollutant

CASNumber

Freshwater

CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

Human Health

 For Consumption of

 Water + OrganismOrganism (μg/L) Only (μ

24

16 Gases, Total Dissolved -- NARRATIVE STATEMENT -- SEE DOCUMENT F 

17 Guthion 86500 0.01 F 0.01 F 18 Hardness -- NARRATIVE STATEMENT-- SEE DOCUMENT 19 Hexachlorocyclo-hexaneTechnical 319868 0.0123 0.0414 

20 Iron 7439896 1,000 F 300 A 

21 Malathion 121755 0.1 F 0.1 F 22 Manganese 7439965 50 A,O 100 A 23 Methoxychlor 72435 0.03 F 0.03 F 100 A,C 24 Mirex 2385855 0.001 F 0.001 F 

25 Nitrates 14797558 10,000 A 

26 Nitrosamines -- 0.0008 1.24 27 Dinitrophenols 25550587 69 5300 28 Nitrosodibutylamine,N 924163 0.0063 A,H 0.22 A

29 Nitrosodiethylamine,N 55185 0.0008 A,H 1.24 A

30 Nitrosopyrrolidine,N 930552 0.016 H 34 H 

31 Oil and Grease -- NARRATIVE STATEMENT -- SEE DOCUMENT F 
Non Priority Pollutant

CASNumber

Freshwater

CMC CCC

 (μg/L) (μg/L) 

 Saltwater CMC CCC (μg/L) (μg/L) 

Human Health

 For Consumption of

 Water + OrganismOrganism (μg/L) Only (μ

25

32 Oxygen, Dissolved

FreshwaterOxygen, DissolvedSaltwater

7782447 WARMWATER AND COLDWATER MATRIX -- SEE DOCUMENT N

SALTWATER – SEE DOCUMENT 

33 Parathion 56382 0.065 J 0.013 J 

34 Pentachlorobenzene 608935 1.4 E 1.5 E 

35 pH -- 6.5 - 9 F 6.5 - 8.5 F,K 5 - 9 

36 Phosphorus Elemental 7723140 0.1 F,K 

37 Nutrients -- See EPA’s Ecoregional criteria for Total Phosphorus, Total Nitrogen, Chlorophyll a a

Water Clarity (Secchi depth for lakes; turbidity for streams and rivers) (& Level III

Ecoregional criteria) 

38 Solids Dissolved and Salinity -- 250,000 A 

39 Solids Suspended and

Turbidity

-- NARRATIVE STATEMENT -- SEE DOCUMENT F 

40 Sulfide-Hydrogen Sulfide 7783064 2.0 F 2.0 F 41 Tainting Substances -- NARRATIVE STATEMENT-- SEE DOCUMENT 42 Temperature -- SPECIES DEPENDENT CRITERIA -- SEE DOCUMENT M 43 Tetrachlorobenzene,1,2,4,5- 95943 0.97 E 1.1 E 

44 Tributyltin (TBT) -- 0.46 Q 0.063 Q 0.37 Q 0.010 Q 

45 Trichlorophenol,2,4,5- 95954 1,800 B,E 3,600 B
26

Footnotes:A This human health criterion is the same as originally published in the Red Book which predates the 1980 methodology and did not utiliz

BCF 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 drinking w

40CFR141 or Safe Drinking Water Hotline (1-800-426-4791) for values. 

D According to the procedures described in the Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of 

and Their Uses, except possibly where a very sensitive species is important at a site, freshwater aquatic life should be protected if both 

in 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) as of May 17

tissue 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 (EPA 440/9-76-023, 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 Na

Criteria for the Protection of Aquatic Organisms and Their Uses, PB85-227049, January 1985) and was issued in one of the following 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 10-6 risk. Alternate risk levels may be obtained by moving the decimal point (e.g., for a risk 

 the decimal point in the recommended criterion one place to the right).

I This value for aluminum is expressed in terms of total recoverable metal in the water column.J This value is based on a 304(a) aquatic life criterion that was issued in the 1995 Updates: Water Quality Criteria Documents for the Pr

Life in Ambient Water (EPA-820-B-96-001). This value was derived using the GLI Guidelines (60FR15393-15399, March 23, 1995; 4A); the differences between the 1985 Guidelines and the GLI Guidelines are explained on page iv of the 1995 Updates. No decision conwas 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 the euphotic zone, the pH should not be changed more than 0.2 

naturally occurring variation or any case outside the range of 6.5 to 8.5. For shallow, highly productive coastal and estuarine areas occurring pH variations approach the lethal limits of some species, changes in pH should be avoided but in any case should not exestablished 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 a toxicity t

bass 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, MVirginia” (May 1994) indicate that aluminum is substantially less toxic at higher pH and hardness, but the effects of pH and hardness are at this time. (2) In tests with the brook trout at low pH and hardness, effects increased with increasing concentrations of total aluminum concentration of dissolved aluminum was constant, indicating that total recoverable is a more appropriate measurement than dissolved, aparticulate aluminum is primarily aluminum hydroxide particles. In surface waters, however, the total recoverable procedure might meaassociated with clay particles, which might be less toxic than aluminum associated with aluminum hydroxide. (3) EPA is aware of field 

many 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 Criteria 1972. EPA-R3-73-033. National Technical Information Service, Springfield, VA.; U.S. EP

Criteria for Freshwater Fish: Protocol and Procedures. EPA-600/3-77-061. National Technical Information Service, Springfield, VA. 
27

N U.S. EPA. 1986. Ambient Water Quality Criteria for Dissolved Oxygen. EPA 440/5-86-003. National Technical Information Service

O This criterion for manganese is not based on toxic effects, but rather is intended to minimize objectionable qualities such as laundry stain

 objectionable tastes in beverages.P Lakes and Reservoirs in Nutrient Ecoregion: II EPA 822-B-00-007, III EPA 822-B-01-008, IV EPA 822-B-01-009, V EPA 822-B-01-

00-008 , VII EPA 822-B-00-009, VIII EPA 822-B-01-015, IX EPA 822-B-00-011, XI EPA 822-B-00-012, XII EPA 822-B-00-013, X

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 EPA 822-B-00-0

013, V EPA 822-B-01-014, VI EPA 822-B-00-017, VII EPA 822-B-00-018, VIII EPA 822-B-01-015, IX EPA 822-B-00-019, X EPA 

EPA 822-B-00-020, XII EPA 822-B-00-021, XIV EPA 822-B-00-022; and Wetlands in Nutrient Ecoregion XIII EPA 822-B-00-023.

Q EPA announced the availability of a draft updated tributyltin (TBT) document on August 7, 1997 (62FR42554). The Agency has reeval

and anticipates releasing an updated document for public comment in the near future.
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NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR ORGANOLEPTIC EFFECTS

 Pollutant CAS Number Organoleptic Effect Criteria (μg/L) FR Ci

1 Acenaphthene 83329 20 Gold Book2 Monochlorobenzene 108907 20 Gold Book3 3-Chlorophenol -- 0.1 Gold Book4 4-Chlorophenol 106489 0.1 Gold Book5 2,3-Dichlorophenol -- 0.04 Gold Book6 2,5-Dichlorophenol -- 0.5 Gold Book7 2,6-Dichlorophenol -- 0.2 Gold Book8 3,4-Dichlorophenol -- 0.3 Gold Book9 2,4,5-Trichlorophenol 95954 1 Gold Book10 2,4,6-Trichloropehnol 88062 2 Gold Book11 2,3,4,6-Tetrachlorophenol -- 1 Gold Book12 2-Methyl-4-Chlorophenol -- 1,800 Gold Book13 3-Methyl-4-Chlorophenol 59507 3,000 Gold Book14 3-Methyl-6-Chlorophenol -- 20 Gold Book15 2-Chlorophenol 95578 0.1 Gold Book16 Copper 7440508 1,000 Gold Book17 2,4-Dichlorophenol 120832 0.3 Gold Book18 2,4-Dimethylpehnol 105679 400 Gold Book19 Hexachlorocyclopentadiene 77474 1 Gold Book20 Nitrobenzene 98953 30 Gold Book
 Pollutant CAS Number Organoleptic Effect Criteria (μg/L) FR Ci

29

21 Pentachlorophenol 87865 30 Gold Book22 Phenol 108952 300 Gold Book23 Zinc 7440666 5,000 45 FR79341

General Notes:1. These criteria are based on organoleptic (taste and odor) effects. Because of variations in chemical nomenclature systems, this listing of 

duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service (CAS) registry numbers, which identification for each chemical.

NATIONAL RECOMMENDED WATER QUALITY CRITERIAAdditional Notes:1. Criteria Maximum Concentration and Criterion Continuous Concentration The Criteria Maximum Concentration (CMC) is an estimate of the highest concentration of a material in surface water to which an aquat

exposed briefly without resulting in an unacceptable effect. The Criterion Continuous Concentration (CCC) is an estimate of the highest con

material in surface water to which an aquatic community can be exposed indefinitely without resulting in an unacceptable effect. The CMC 

two of the six parts of an aquatic life criterion; the other four parts are the acute averaging period, chronic averaging period, acute frequency exceedence, and chronic frequency of allowed exceedence. Because 304(a) aquatic life criteria are national guidance, they are intended to bvast majority of the aquatic communities in the United States.2. Criteria Recommendations for Priority Pollutants, Non Priority Pollutants and Organoleptic Effects

This compilation lists all priority toxic pollutants and some non priority toxic pollutants, and both human health effect and organoleptic e

pursuant to CWA §304(a). Blank spaces indicate that EPA has no CWA §304(a) criteria recommendations. For a number of non-priority t

listed, CWA §304(a) “water + organism” human health criteria are not available, but EPA has published MCLs under the SDWA that may bestablishing water quality standards to protect water supply designated uses. Because of variations in chemical nomenclature systems, this lpollutants does not duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service CAS registry nuprovide a unique identification for each chemical.3. Human Health Risk The human health criteria for the priority and non priority pollutants are based on carcinogenicity of 10-6 risk. Alternate risk levels may 

moving 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 CWA

Many of the values in the compilation were published in the California Toxics Rule. Although such values were published pursuant to S

CWA, they represent the Agency’s most recent calculation of water quality criteria and are thus the Agency’s 304(a) criteria. 
30

5. Calculation of Dissolved Metals Criteria

The 304(a) criteria for metals, shown as dissolved metals, are calculated in one of two ways. For freshwater metals criteria that are hard

dissolved metal criteria were calculated using a hardness of 100 mg/l as CaCO3 for illustrative purposes only. Saltwater and freshwater met

not hardness-dependent are calculated by multiplying the total recoverable criteria before rounding by the appropriate conversion factors. Tmetals’ criteria in the table are rounded to two significant figures. Information regarding the calculation of hardness dependent conversion fin the footnotes.6. Maximum Contaminant Levels

The compilation includes footnotes for pollutants with Maximum Contaminant Levels (MCLs) more stringent than the recommended wa

the compilation. MCLs for these pollutants are not included in the compilation, but can be found in the appropriate drinking water regulatio16 and 141.60-63), or can be accessed through the Safe Drinking Water Hotline (800-426-4791) or the Internet

(http://www.epa.gov/waterscience/drinking/standards/dwstandards.pdf).7. Organoleptic Effects

The compilation contains 304(a) criteria for pollutants with toxicity-based criteria as well as non-toxicity based criteria. The basis for th

criteria are organoleptic effects (e.g., taste and odor) which would make water and edible aquatic life unpalatable but not toxic to humans. Tcriteria for organoleptic effects for 23 pollutants. Pollutants with organoleptic effect criteria more stringent than the criteria based on toxicit

both the priority and non-priority pollutant tables) are footnoted as such.8. Gold Book

The “Gold Book” is Quality Criteria for Water: 1986. EPA 440/5-86-001.

9. Correction of Chemical Abstract Services Number

The Chemical Abstract Services number (CAS) for Bis(2-Chlorisoprpyl) Ether, has been revised in IRIS and in the table. The correct C

chemical is 108-60-1. The previous CAS number for this pollutant was 39638-32-9.10. Contaminants with Blanks

EPA has not calculated criteria for contaminants with blanks. However, permit authorities should address these contaminants in NPDES 

the States’ existing narrative criteria for toxics.11. Specific Chemical Calculations

A. SeleniumAquatic Life

 This compilation contains aquatic life criteria for selenium that are the same as those published in the proposed CTR. In the CTR, EPA 

criterion for selenium based on the criterion proposed for selenium in the Water Quality Guidance for the Great Lakes System (61 FR 58444

CTR proposals take into account data showing that selenium’s two prevalent oxidation states in water, selenite and selenate, present differinaquatic toxicity, as well as new data indicating that various forms of selenium are additive. The new approach produces a different selenium concentration, 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 the 304(a) criteria for selenium will be revised based on the final 

(63FR26186). However, until such time as revised water quality criteria for selenium are published by the Agency, the recommended water 

this compilation are EPA’s current 304(a) criteria.
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Appendices:Appendix A - Conversion Factors for Dissolved Metals

Metal Conversion Factor freshwater CMC Conversion Factor freshwater CCC Conversion Factor saltwater CMC Conversion Fac

saltwater CCC

Arsenic 1.000 1.000 1.000 1.000Cadmium 1.136672-[(ln hardness)(0.041838)] 1.101672-[(ln hardness)(0.041838)] 0.994 0.994

Chromium III 0.316 0.860 -- --Chromium VI 0.982 0.962 0.993 0.993Copper 0.960 0.960 0.83 0.83Lead 1.46203-[(ln hardness)(0.145712)] 1.46203-[(ln hardness)(0.145712)] 0.951 0.951Mercury 0.85 0.85 0.85 0.85Nickel 0.998 0.997 0.990 0.990Selenium -- -- 0.998 0.998Silver 0.85 -- 0.85 --Zinc 0.978 0.986 0.946 0.946
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Appendix B - Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Depen

Chemical mA bA mC bC

Freshwater Conversion Factors (CF)

CMC CCC

Cadmium 1.0166 -3.924 0.7409 -4.719 1.136672-[(ln hardness)(0.041838)] 1.101672-[(ln hardness)(0.041838

Chromium III 0.8190 3.7256 0.8190 0.6848 0.316 0.860Copper 0.9422 -1.700 0.8545 -1.702 0.960 0.960Lead 1.273 -1.460 1.273 -4.705 1.46203-[(ln hardness)(0.145712)] 1.46203-[(ln hardness)(0.145712

Nickel 0.8460 2.255 0.8460 0.0584 0.998 0.997Silver 1.72 -6.59 -- -- 0.85 --Zinc 0.8473 0.884 0.8473 0.884 0.978 0.986

 Hardness-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)
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Appendix 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 ythe CMC (acute criterion) calculated using the following equations. 

Where salmonid fish are present:

 0.275 39.0

CMC = -------------------- + ------------------------

 1 + 107.204-pH 1 + 10pH-7.204

 Or where salmonid fish are not present:

 0.411 58.4

CMC = -------------------- + ------------------------

 1 + 107.204-pH 1 + 10pH-7.204

2A The thirty-day average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three average, the CCC (chronic criterion) calculated using the following equations.

When fish early life stages are present:

 0.0577 2.487

CCC = ‰ -------------------- + ------------------------  C MIN (2.85, 1.45 @100.028@(25-T))

 1 + 107.688-pH 1 + 10pH-7.688

When fish early life stages are absent:

 0.0577 2.487CCC = ‰ -------------------- + ------------------------  C 1.45 @100.028@(25-MAX (T,7))

 1 + 107.688-pH 1 + 10pH-7.6882B. In addition, the highest four-day average within the 30-day period should not exceed 2.5 times the CCC.