National Recommended Water Quality Criteria - Aquatic Life 

Criteria Table

Aquatic life criteria for toxic chemicals are the highest concentration of specific pollutants or parameters in water that are not expected to pose 

a significant risk to the majority of species in a given environment or a narrative description of the desired conditions of a water body being 

"free from" certain negative conditions. The table below lists EPA's recommended aquatic life criteria. State and tribal governments may use 

these criteria or use them as guidance in developing their own.

On this page:

• National Recommended Aquatic Life Criteria Table

• Appendix A - Conversion Factors for Dissolved Metals

• Appendix B - Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Dependent

National Recommended Aquatic Life Criteria table

Aquatic Life Criteria

Pollutant

(P = Priority 

Pollutant)

CAS (Chemical 

Abstracts 

Service) Number

Freshwater 

CMC (Criteria 

Maximum 

Concentration)

1

(acute)

(μg/L)

Freshwater 

CCC

(Criterion 

Continuous 

Concentration)

2

(chronic)

(μg/L)

Saltwater 

CMC (Criteria 

Maximum 

Concentration)

1

(acute)

(μg/L)

Saltwater 

CCC

(Criterion 

Continuous 

Concentration)

2

(chronic)

(μg/L)

Publication 

Year Notes

Acrolein (P) 107028 3ug/L 3ug/L — — 2009

Aesthetic Qualities — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narrative statement.

Aldrin (P) 309002 3.0 — 1.3 — 1980

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from the 

1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

Alkalinity — — 20000 — — 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

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alpha-Endosulfan (P) 959988 0.22 0.056 0.034 0.0087 1980

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from 

the 1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

This value was derived 

from data for 

endosulfan and is most 

appropriately applied 

to the sum of alphaendosulfan and betaendosulfan.

Aluminum pH 6.5 – 

9.0 7429905 750 87 — — 1988

This value for 

aluminum is expressed 

in terms of total 

recoverable metal in 

the water column.

Ammonia 7664417 — — — —

2013 

(Freshwater),

1989 

(Saltwater)

Freshwater criteria are 

ph, temperature and 

life-stage dependent. 

Saltwater criteria are 

pH and temperature 

dependent. 

Arsenic 7440382 340 150 69 36 1995

This recommended 

water quality criterion 

was derived from data 

for arsenic (III), but is 

applied here to total 

arsenic.

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

Atrazine 1912249

Bacteria — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

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beta-Endosulfan (P) 33213659 0.22 0.056 0.034 0.0087 1980

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from 

the 1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

This value was derived 

from data for 

endosulfan and is most 

appropriately applied 

to the sum of alphaendosulfan and betaendosulfan.

Boron — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Carbaryl 63252 2.1 2.1 1.6 — 2012

Cadmium (P) 7440439 2.0 0.25 40 8.8 2001

The freshwater 

criterion for this metal 

is expressed as a 

function of hardness 

(mg/L). The value 

given here corresponds 

to a hardness of 100 

mg/L. 

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

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Chlordane (P) 57749 2.4 0.0043 0.09 0.004 1980

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from 

the 1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

Chloride 16887006 860000 230000 — — 1986

Chlorine 7782505 19 11 13 7.5 1986

Chloropyrifos 2921882 0.083 0.041 0.011 0.0056 1986

Chromium (III) (P) 16065831 570 74 — — 1995

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

The freshwater 

criterion for this metal 

is expressed as a 

function of hardness 

(mg/L). The value 

given here corresponds 

to a hardness of 100 

mg/L. 

Chromium (VI) (P) 18540299 16 11 1,100 50 1995

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

Color — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

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Copper (P) 7440508 — — 4.8 3.1 2007

Freshwater criteria 

calculated using the 

Biotic Ligand Model. 

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

Cyanide (P) 57125 22 5.2 1 1 1985

These recommended 

water quality criteria 

are expressed as ug 

free cyanide (CN/L).

Demeton 8065483 — 0.1 — 0.1 1985

Diazinon 333415 0.17ug/L 0.17ug/L 0.82ug/L 0.82ug/L 2005

Dieldrin (P) 60571 0.24 0.056 0.71 0.0019 1995

The freshwater 

CCC criterion and 

both Saltwater criteria 

are based are based on 

the 1980 criteria which 

used different 

Minimum Data 

Requirements and 

derivation procedures 

from the 1985 

Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

Endrin (P) 72208 0.086 0.036 0.037 0.0023 1995

The derivation of the 

CCC for this pollutant 

did not consider 

exposure through the 

diet, which is probably 

important for aquatic 

life occupying upper 

trophic levels.

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gamma-BHC 

(Lindane) (P) 58899 0.95 — 0.16 — 1995

The Saltwater CCC 

criterion is based on 

the 1980 criteria which 

used different 

Minimum Data 

Requirements and 

derivation procedures 

from the 1985 

Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

Gases, Total 

Dissolved — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Guthion 86500 — 0.01 — 0.01 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

Hardness — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Heptachlor (P) 76448 0.52 0.0038 0.053 0.0036 1980

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from 

the 1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

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Heptachlor 

Epoxide (P) 1024573 0.52 0.0038 0.053 0.0036 1981

These criteria are 

based on the 1980 

criteria which used 

different Minimum 

Data Requirements 

and derivation 

procedures from 

the 1985 Guidelines. If 

evaluation is to be 

done using an 

averaging period, the 

acute criteria values 

given should be 

divided by 2 to obtain 

a value that is more 

comparable to a CMC 

derived using the 1985 

Guidelines.

This value was derived 

from data for 

heptachlor andthere 

was insufficient data to 

determine relative 

toxicities of heptachlor 

and heptachlor 

epoxide.

Iron 7439896 — 1000 — — 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

Lead (P) 7439921 65 2.5 210 8.1 1980

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

The freshwater 

criterion for this metal 

is expressed as a 

function of hardness 

(mg/L). The value 

given here corresponds 

to a hardness of 100 

mg/L. 

Malathion 121755 — 0.1 — 0.1 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

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Mercury 

Methylmercury (P)

7439976 

22967926 1.4 0.77 1.8 0.94 1995

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

Methoxychlor 72435 — 0.03 — 0.03 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

Methyl Tertiary-Butyl 

Ether (MTBE)

Mirex 2385855 — 0.001 — 0.001 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

Nickel (P) 7440020 470 52 74 8.2 1995

Freshwater and 

saltwater criteria for 

metals are expressed in 

terms of the dissolved 

metal in the water 

column. See Office of 

Water Policy and 

Technical Guidance on 

Interpretation and 

Implementation of 

Aquatic Life Metals 

Criteria.

The freshwater 

criterion for this metal 

is expressed as a 

function of hardness 

(mg/L). The value 

given here corresponds 

to a hardness of 100 

mg/L. 

Nonylphenol 84852153 28 ug/L 6.6 ug/L 7 ug/L 1.7 ug/L 2005

Nutrients — — — — — —

See EPA's Ecoregional 

criteria for Total 

Phosphorus, Total 

Nitrogen, 

Chlorophyll a and 

Water Clarity (Secchi 

depth for lakes; 

turbidity for streams 

and rivers) (& Level 

III Ecoregional 

criteria)

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Oil and Grease — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Oxygen, Dissolved 

Freshwater

Oxygen, Dissolved 

Saltwater

7782447 — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

freshwater. For 

saltwater, see Aquatic 

Life Criteria for 

Dissolved 

Oxygen (Saltwater) 

Cape Cod to Cape 

Hatteras.

Parathion 56382 0.065 0.013 — — 1995

Pentachlorophenol (P)87865 19 15 13 7.9 1995

Freshwater aquatic life 

values for 

pentachlorophenol are 

expressed as a function 

of pH and values 

displayed in table 

correspond to a pH of 

7.8.

pH — — 6.5 – 9 — 6.5 – 8.5 1986

The CCC of 20mg/L is 

a minimum value 

except where 

alkalinity is naturally 

lower, in which case 

the criterion cannot be 

lower than 25% of the 

natural level.

For open ocean waters 

where the depth is 

substantially greater 

than the euphotic zone, 

the pH should not be 

changed more than 0.2 

units from the 

naturally occurring 

variation or any case 

outside the range of 

6.5 to 8.5. For shallow, 

highly productive 

coastal and estuarine 

areas where naturally 

occurring pH 

variations approach 

the lethal limits of 

some species, changes 

in pH should be 

avoided but in any 

case should not exceed 

the limits established 

for fresh water, i.e., 

6.5-9.0.

Phosphorus 

Elemental 7723140 — — — — 1986

Polychlorinated 

Biphenyls (PCBs) (P) — — 0.014 — 0.03 —

This criterion applies 

to total PCBs, (e.g., 

the sum of all 

congener or all isomer 

or homolog or Aroclor 

analyses.)

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Selenium (P) 7782492 — 5.0 290 71 1999

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 

CMC1 and CMC2 are 

185.9 ug/l and 12.82 

ug/l, respectively. 

However, based on 

findings from a 

February 2009 SETAC 

Pellston Workshop on 

Ecological Assessment 

of Selenium in the 

Aquatic Environment, 

diet is the primary 

pathway of selenium 

exposure to aquatic 

life, and traditional 

methods for predicting 

toxicity on the basis of 

exposure to dissolved 

concentrations are not 

appropriate for 

selenium. 

Silver (P) 7440224 3.2 — 1.9 — 1980

Solids Suspended and 

Turbidity — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Sulfide-Hydrogen 

Sulfide 7783064 — 2.0 — 2.0 1986

Tainting Substances — — — — — 1986

See Quality Criteria 

for Water, 1986 

("Gold Book") for 

narative statement.

Temperature — — — — — 1986

Criteria is species 

dependant. See Quality 

Criteria 

for Water, 1986 

("Gold Book").

Toxaphene (P) 8001352 0.73 0.0002 0.21 0.0002 1986

Tributyltin (TBT) — 0.46 0.072 0.42 0.0074 2004

Zinc (P) 7440666 120 120 90 81 1995

4,4'-DDT (P) 50293 1.1 0.001 0.13 0.001 1980

Appendix A

Conversion Factors for Dissolved Metals

Metal Freshwater CMC Freshwater CCC Saltwater CMCSaltwater CCC

Arsenic 1.000 1.000 1.000 1.000

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

Chromium III 0.316 0.860 — —

Chromium VI0.982 0.962 0.993 0.993

Copper 0.960 0.960 0.83 0.83

Lead 1.46203-[(ln hardness)(0.145712)] 1.46203-[(ln hardness)(0.145712)] 0.951 0.951

Mercury 0.85 0.85 0.85 0.85

Nickel 0.998 0.997 0.990 0.990

Selenium — — 0.998 0.998

Silver 0.85 — 0.85 —

Zinc 0.978 0.986 0.946 0.946

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Last updated on January 25, 2016

Appendix B

Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Dependent

Chemical mA bA mC bC Freshwater Conversion Factors (CF)

CMC CCC

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

Chromium III0.81903.72560.81900.68480.316 0.860

Copper 0.9422-1.700 0.8545-1.702 0.960 0.960

Lead 1.273 -1.460 1.273 -4.705 1.46203-[(lnhardness)(0.145712)] 1.46203-[(lnhardness)(0.145712)]

Nickel 0.84602.255 0.84600.05840.998 0.997

Silver 1.72 -6.59 — — 0.85 —

Zinc 0.84730.884 0.84730.884 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)

1/ CMC: Criterion Maximum Concentration

2/ CCC: Criterion Continuous Concentration

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