National Recommended

Water Quality Criteria

View this document online at http://water.epa.gov/scitech/swguidance/standards/current/

Envi

Age

United States Office of Water 

ronmental Protection 

ncy

Office of Science and Technology 

(4304T) 

2009 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

1

Priority Pollutants

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

1 Antimony 7440360 5.6 

B 

640 

B 

2

65 FR 66443 

Arsenic 7440382 340 

A,D,K 

150 

A,D,K 

69 

A,D,bb 

36 

A,D,bb 

0.018 

C,M,S 

0.14 

C,M,S 

65 FR 31682

57 FR 60848

3 Beryllium 7440417 Z 

4

65 FR 31682 

Cadmium 7440439 2.0 

D,E,K,bb 

0.25 

D,E,K,bb 

40 

D,bb 

8.8 

D,bb 

Z EPA 822R-01-001 

65 FR 31682 

5a Chromium (III) 16065831 570 

D,E,K 

74 

D,E,K 

Z Total EPA 820B-96-001 

65 FR 31682 

5b Chromium (VI) 18540299 16 

D,K 

11 

D,K 

1,100 

D,bb 

50 

D,bb 

Z Total 

6

65 FR 31682 

Copper 7440508 Freshwater criteria 

calculated using the 

BLM mm - See 

Document

(epa.gov/waterscience/c

riteria/copper/)

4.8 

D,cc,ff 

3.1 

D,cc,ff 

1,300 

U 

EPA-822-R-07-001

65 FR 31682 

72 FR 7983 

7 Lead 7439921 65 

D,E,bb,gg 

2.5 

D,E,bb,gg 

210 

D,bb 

8.1 

D,bb 

8a

65 FR 31682 

8b

Mercury

Methylmercury 

7439976

22967926 

1.4 

D,K,hh 

0.77

D,K,hh 

1.8

D,ee,hh 

0.94

D,ee,hh 

0.3 mg/kg 

J 

62 FR 42160 

EPA 823R-01-001 

9 Nickel 7440020 470

D,E,K 

52 

D,E,K 

74 

D,bb 

8.2 

D,bb 

610

B 

4,600

B 

10

65 FR 31682 

Selenium 7782492 L,R,T 5.0 

T 

290

D,bb,dd 

71

D,bb,dd 

170 

Z 

4200 62 FR 42160 

65 FR 31682 

65 FR 66443 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

2

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

11 Silver 7440224 3.2 

D,E,G 

1.9 

D,G 

12

65 FR 31682 

Thallium 7440280 0.24 0.47 

13

68 FR 75510 

Zinc 7440666 120 

D,E,K 

120 

D,E,K 

90 

D,bb 

81 

D,bb 

7,400

U 

26,000 

U 

65 FR 31682 

65 FR 66443 

14 Cyanide 57125 22

K,Q 

5.2

K,Q 

1

Q,bb 

1 

Q,bb 

140

jj 

140

jj 

EPA 820B-96001 

57 FR 60848 

68 FR 75510 

15 Asbestos 1332214 7 million 

fibers/L 

I 

57 FR 60848

16 2,3,7,8-TCDD (Dioxin) 1746016 5.0E-9

C 

5.1E-9

C 

17

65 FR 66443 

Acrolein 107028 3ug/L 3ug/L 6

ll 

9 

ll 

74 FR 27535 

74 FR 46587 

18 Acrylonitrile 107131 0.051 

B,C 

0.25 

B,C 

65 FR 66443 

19 Benzene 71432 2.2 

B,C 

51 

B,C 

IRIS 01/19/00 

65 FR 66443 

20

Bromoform 75252 4.3 

B,C 

140 

B,C 

65 FR 66443 

21 Carbon Tetrachloride 56235 0.23 

B,C 

1.6

B,C 

65 FR 66443 

22 Chlorobenzene 108907 130 

Z,U 

1,600 

U 

68 FR 75510 

23 Chlorodibromomethane 124481 0.40 

B,C 

13

B,C 

65 FR 66443 

24 Chloroethane 75003 

25 2-Chloroethylvinyl Ether 110758 

26 Chloroform 67663 5.7 

C,P 

470 

C,P 

62 FR 42160 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

3

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

27 Dichlorobromomethane 75274 0.55

B,C 

17

B,C 

28

65 FR 66443 

1,1-Dichloroethane 75343 

29 1,2-Dichloroethane 107062 0.38 

B,C 

37 

B,C 

30

65 FR 66443 

1,1-Dichloroethylene 75354 330 7,100 

31

68 FR 75510 

1,2-Dichloropropane 78875 0.50

B,C 

15 

B,C 

32

65 FR 66443 

1,3-Dichloropropene 542756 0.34 

C 

21 

C 

33

68 FR 75510 

Ethylbenzene 100414 530 2,100 

34

68 FR 75510 

Methyl Bromide 74839 47 

B 

1,500 

B 

35

65 FR 66443 

Methyl Chloride 74873 

36

65 FR 31682 

Methylene Chloride 75092 4.6 

B,C 

590 

B,C 

37

65 FR 66443 

1,1,2,2-Tetrachloroethane 79345 0.17 

B,C 

4.0 

B,C 

38

65 FR 66443 

Tetrachloroethylene 127184 0.69 

C 

3.3 

C 

39

65 FR 66443 

Toluene 108883 1,300 Z 15,000 

40

68 FR 75510 

1,2-Trans-Dichloroethylene 156605 140 Z 10,000 

41

68 FR 75510 

1,1,1-Trichloroethane 71556 Z 

42

65 FR 31682 

1,1,2-Trichloroethane 79005 0.59 

B,C 

16 

B,C 

43

65 FR 66443 

Trichloroethylene 79016 2.5 

C 

30 

C 

44

65 FR 66443 

Vinyl Chloride 75014 0.025 

C,kk 

2.4 

C,kk 

45

68 FR 75510 

2-Chlorophenol 95578 81 

B,U 

150 

B,U 

65 FR 66443
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

4

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

46 2,4-Dichlorophenol 120832 77 

B,U 

290 

B,U 

47

65 FR 66443 

2,4-Dimethylphenol 105679 380 

B

850 B,U 

48

65 FR 66443 

2-Methyl-4,6Dinitrophenol 534521 13 280

49

65 FR 66443 

2,4-Dinitrophenol 51285 69 B 5,300 B

50

65 FR 66443 

2-Nitrophenol 88755 

51 4-Nitrophenol 100027 

52 3-Methyl-4-Chlorophenol 59507 U U

53 Pentachlorophenol 87865 19 F,K 15

F,K

13 bb 7.9

bb

0.27

B,C 

3.0 

B,C,H

54

65 FR 31682 

Phenol 108952 10,000

ll,U

860,000 

ll,U

55

74 FR 27535

2,4,6-Trichlorophenol 88062 1.4

B,C

2.4 

B,C,U

56

65 FR 66443 

Acenaphthene 83329 670 

B,U

990 

B,U 

57

65 FR 66443 

Acenaphthylene 208968 

58

65 FR 66443 

Anthracene 120127 8,300 

B 

40,000 B

59

65 FR 66443 

Benzidine 92875 0.000086 

B,C

0.00020 

B,C

60

65 FR 66443 

Benzo(a) Anthracene 56553 0.0038 

B,C 

 0.018 

B,C

61

65 FR 66443 

Benzo(a) Pyrene 50328 0.0038 

B,C

0.018 

B,C 

62

65 FR 66443 

Benzo(b) Fluoranthene 205992 0.0038 

B,C

0.018 

B,C 

63

65 FR 66443 

Benzo(ghi) Perylene 191242 

64

65 FR 66443 

Benzo(k) Fluoranthene 207089 0.0038 

B,C

0.018 

B,C

65 FR 66443 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

5

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

65 Bis(2-Chloroethoxy) 

Methane 

111911 

66 Bis(2-Chloroethyl) Ether 111444 0.030 

B,C 

0.53 

B,C 

67

65 FR 66443 

Bis(2-Chloroisopropyl) 

Ether 

108601 1,400 

B

65,000 

B

68

65 FR 66443 

Bis(2-Ethylhexyl) 

PhthalateX

117817 1.2 

B,C

2.2 

B,C

69

65 FR 66443 

4-Bromophenyl Phenyl 

Ether 

101553 

70

Butylbenzyl PhthalateW 85687 1,500 

B 

1,900 

B 

71

65 FR 66443 

2-Chloronaphthalene 91587 1,000 

B 

1,600 

B 

72

65 FR 66443 

4-Chlorophenyl Phenyl 

Ether 

7005723 

73 Chrysene 218019 0.0038

B,C 

0.018

B,C 

74

65 FR 66443 

Dibenzo(a,h)Anthracene 53703 0.0038 

B,C 

0.018 

B,C 

75

65 FR 66443 

1,2-Dichlorobenzene 95501 420 1,300 

76

68 FR 75510 

1,3-Dichlorobenzene 541731 320 960 

77

65 FR 66443 

1,4-Dichlorobenzene 106467 63 190 

78

68 FR 75510 

3,3'-Dichlorobenzidine 91941 0.021 

B,C 

0.028 

B,C 

79

65 FR 66443 

Diethyl PhthalateW 84662 17,000 

B 

44,000 

B 

80

65 FR 66443 

Dimethyl PhthalateW 131113 270,000 1,100,000 

81

65 FR 66443 

Di-n-Butyl PhthalateW 84742 2,000 

B 

4,500 

B 

82

65 FR 66443 

2,4-Dinitrotoluene 121142 0.11 

C 

3.4 

C 

83

65 FR 66443 

2,6-Dinitrotoluene 606202 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

6

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

84 Di-n-Octyl Phthalate 117840 

85 1,2-Diphenylhydrazine 122667 0.036 

B,C 

0.20 

B,C 

86

65 FR 66443 

Fluoranthene 206440 130 

B 

140 

B 

87

65 FR 66443 

Fluorene 86737 1,100

B 

5,300

B 

88

65 FR 66443 

Hexachlorobenzene 118741 0.00028 

B,C 

0.00029 

B,C 

89

65 FR 66443 

Hexachlorobutadiene 87683 0.44 

B,C 

18 

B,C 

90

65 FR 66443 

Hexachlorocyclopentadiene 77474 40

U 

1,100 

U 

91

68 FR 75510 

Hexachloroethane 67721 1.4 

B,C 

3.3 

B,C 

92

65 FR 66443 

Ideno(1,2,3-cd)Pyrene 193395 0.0038

B,C 

0.018

B,C 

93

65 FR 66443 

Isophorone 78591 35 

B,C 

960

B,C 

94

65 FR 66443 

Naphthalene 91203 

95

Nitrobenzene 98953 17 

B 

690 

B,H,U 

96

65 FR 66443 

N-Nitrosodimethylamine 62759 0.00069

B,C 

3.0 

B,C 

97

65 FR 66443 

N-Nitrosodi-n-Propylamine 621647 0.0050 

B,C 

0.51 

B,C 

98

65 FR 66443 

N-Nitrosodiphenylamine 86306 3.3

B,C 

6.0

B,C 

99

65 FR 66443 

Phenanthrene 85018 

100 Pyrene 129000 830 

B 

4,000 

B 

101

65 FR 66443 

1,2,4-Trichlorobenzene 120821 35 70 68 FR 75510 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

7

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

102 Aldrin 309002 3.0 

G 

1.3 

G 

0.000049

B,C 

0.000050 

B,C 

65 FR 31682 

65 FR 66443 

103 alpha-BHC 319846 0.0026 

B,C 

0.0049

B,C 

104

65 FR 66443 

beta-BHC 319857 0.0091

B,C 

0.017

B,C 

105

65 FR 66443 

gamma-BHC (Lindane) 58899 0.95 

K 

0.16 G 0.98 1.8 65 FR 31682 

68 FR 75510 

106 delta-BHC 319868 

107 Chlordane 57749 2.4 

G 

0.0043

G,aa 

0.09 

G 

0.004 

G,aa 

0.00080 

B,C 

0.00081 

B,C 

65 FR 31682 

65 FR 66443 

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 

0.00022 

B,C 

65 FR 31682 

65 FR 66443 

109 4,4'-DDE 72559 0.00022

B,C 

0.00022 

B,C 

110

65 FR 66443 

4,4'-DDD 72548 0.00031 

B,C 

0.00031 

B,C 

111

65 FR 66443 

Dieldrin 60571 0.24 

K 

0.056 

K,O 

0.71 

G 

0.0019 

G,aa 

0.000052 

B,C 

0.000054 

B,C 

65 FR 31682 

65 FR 66443 

112 alpha-Endosulfan 959988 0.22 

G,Y 

0.056 

G,Y 

0.034

G,Y 

0.0087 

G,Y 

62 

B 

89

B 

65 FR 31682 

65 FR 66443 

113 beta-Endosulfan 33213659 0.22 

G,Y 

0.056 

G,Y 

0.034 

G,Y 

0.0087

G,Y 

62

B 

89

B 

65 FR 31682 

65 FR 66443 

114 Endosulfan Sulfate 1031078 62 

B 

89

B 

115

65 FR 66443 

Endrin 72208 0.086 

K 

0.036 

K,O 

0.037

G 

0.0023 

G,aa 

0.059 0.060 65 FR 31682 

68 FR 75510 

116 Endrin Aldehyde 7421934 0.29 

B 

0.30 

B,H 

65 FR 66443 

117 Heptachlor 76448 0.52 

G 

0.0038 

G,aa 

0.053 

G 

0.0036

G,aa 

0.000079 

B,C 

0.000079 

B,C 

65 FR 31682 

65 FR 66443 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

8

Freshwater Saltwater Human Health for the 

consumption of

Priority Pollutant CAS

Number

CMC 1 

(acute)

(μg/L)

CCC 1 

(chronic) 

(μg/L)

CMC 1 

(acute) 

(μg/L)

CCC 1 

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organism 

Only 

(μg/L)

FR Cite / Source

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 

0.000039 

B,C 

65 FR 31682 

65 FR 66443 

119 Polychlorinated Biphenyls 

(PCBs) 

0.014

N,aa 

0.03 

N,aa 

0.000064 

B,C,N 

0.000064 

B,C,N 

65 FR 31682 

65 FR 66443 

120 Toxaphene 8001352 0.73 0.0002 

aa 

0.21 0.0002 

aa 

0.00028 

B,C 

0.00028 

B,C 

65 FR 31682 

65 FR 66443 

Footnotes 

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

and arsenic (V) are equally toxic to aquatic life and that their toxicities are additive. In the arsenic criteria document (PDF) (74 pp., 3.2 MB) (EPA 440/5-84-033, 

January 1985), Species 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 

from 0.6 to 

1.7. Chronic values are available for both arsenic (III) and arsenic (V) for one species; for the fathead minnow, the chronic value for arsenic (V) is 

0.29 times the chronic 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 10-6 risk. Alternate risk levels may be obtained by moving the decimal point (e.g., for a risk level of 10-5

D Freshwater and saltwater criteria for metals are expressed in terms of the dissolved metal in the water column. The recommended water quality criteria 

value 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 recoverable 

fraction in the water column to a criterion expressed as the dissolved fraction in the water column. (Conversion Factors for saltwater CCCs are not currently 

available. Conversion factors derived for saltwater CMCs have been used for both saltwater CMCs and CCCs). See "

, move 

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

Office of Water Policy and Technical 

Guidance on Interpretation and Implementation of Aquatic Life Metals Criteria (PDF)," (49 pp., 3MB) October 1, 1993, by Martha G. Prothro, Acting Assistant 

Administrator for Water, available from the Water Resource center 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. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

9

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 

of 100 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

and the parameters specified in Appendix B-Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Dependent. 

} (CF) 

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 (PDF) (153 pp., 7.3 

MB) (EPA 440/5-80-019), Chlordane (PDF) (68 pp., 3.1 MB) (EPA 440/5-80-027), DDT (PDF) (175 pp., 8.3 MB) (EPA 440/5-80-038), Endosulfan (PDF) (155 pp., 7.3 

MB) (EPA 440/5-80-046), Endrin (PDF) (103 pp., 4.6 MB) (EPA 440/5-80-047), Heptachlor (PDF) (114 pp., 5.4 MB) (EPA 440/5-80-052), Hexachlorocyclohexane 

(PDF) (109 pp., 4.8 MB) (EPA 440/5-80-054), Silver (EPA 440/5-80-071). The Minimum Data Requirements and derivation procedures were different in the 1980 

Guidelines than in the 1985 Guidelines (PDF) (104 pp., 3.3 MB) . For example, a "CMC" derived using the 1980 Guidelines was derived to be used as an 

instantaneous 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 more 

comparable 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 the 

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

Protection of Aquatic Life in Ambient Water

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, respectively, and 

CMC1 and CMC2 are 185.9 g/l and 12.82 g/l, respectively. 

, (EPA 820-B-96-001, September 1996). This value was derived using the GLI Guidelines (60 FR 15393-15399, 

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 the Great Lakes. 

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 occupying 

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 Regulations: Stage 2 

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

anticipated. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

10

Q This recommended water quality criterion is expressed as g free cyanide (as CN)/L. 

R This value for selenium was announced (61 FR 58444-58449, November 14, 1996) as a proposed GLI 303(c) aquatic life criterion. EPA is currently 

working 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 scientifically acceptable to 

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 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 relative toxicities of heptachlor and 

heptachlor epoxide. 

W Although EPA has not published a completed criteria document for butylbenzyl phthalate it is EPA's understanding that sufficient data exist to allow 

calculation of aquatic criteria. It is anticipated that industry intends to publish in the peer reviewed literature draft aquatic life criteria generated in 

accordance 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 (1-800-426-4791) for 

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: Aldrin/Dieldrin (PDF) 

(153 pp., 7.3 MB) (EPA 440/5-80-019), Chlordane (PDF) (68 pp., 3.1 MB) (EPA 440/5-80027), DDT (PDF) (175 pp., 8.3 MB) (EPA 440/5-80-038), Endrin (PDF) (103 pp., 

4.6 MB) (EPA 440/5-80-047), Heptachlor (PDF) 

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

(114 pp., 5.4 MB) (EPA 440/5-80-052), Polychlorinated biphenyls (EPA 440/5-80-068), Toxaphene (EPA 440/5-86-

006). This CCC is currently based on the Final Residue Value (FRV) procedure. Since the publication of the Great Lakes Aquatic Life Criteria Guidelines in 1995 

(60 FR 15393-15399, March 23, 1995), the Agency no longer uses the Final Residue Value procedure for deriving CCCs for new or revised 304(a) aquatic life 

criteria. Therefore, the Agency anticipates that future revisions of this CCC will not be based on the FRV procedure. 

1985 Guidelines (PDF) (104 pp., 3.3 MB) (Guidelines for 

Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses, PB85-227049, January 1985) and was issued in one 

of the following criteria documents: Arsenic (PDF) (74 pp., 3.2 MB) (EPA 440/5-84-033), Cadmium (EPA 822-R-01-001), Chromium (EPA 440/5-84-029), Copper 

(PDF) (150 pp., 6.2 MB) (EPA 440/5-84-031), Cyanide (PDF) (67 pp., 2.7 MB) (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). 

cc When the concentration of dissolved organic carbon is elevated, copper is substantially less toxic and use of Water-Effect Ratios might be appropriate. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR PRIORITY POLLUTANTS

11

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 

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

because the 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 (PDF) (144 pp., 6.4 MB) (EPA 440/5-84-026, January 

1985). The saltwater CCC 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 the publication of the Great Lakes Aquatic Life Criteria Guidelines in 1995 (60 FR 15393-15399, March 23, 1995), the Agency no longer uses the Final 

Residue Value procedure for 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, 1995) and was 

promulgated in the Interim final National Toxics Rule (60 FR 22228-222237, 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 substantial portion of 

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

methylmercury and methylmercury bioaccumulates to a great extent, this criterion does not account for uptake via the food chain because sufficient data 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). 

jj This recommended water quality criterion is expressed as total cyanide, even though the IRIS RFD we used to derive the criterion is based on free cyanide. 

The multiple forms of cyanide that are present in ambient water have significant differences in toxicity due to their differing abilities to liberate the CNmoiety. Some complex cyanides require even more extreme conditions than refluxing with sulfuric acid to liberate the CN-moiety. Thus, these complex 

cyanides are expected to have little or no 'bioavailability' to humans. If a substantial fraction of the cyanide present in a water body is present in a complexed 

form (e.g., Fe4[Fe(CN) 6] 3

kk This recommended water quality criterion was derived using the cancer slope factor of 1.4 (LMS exposure from birth). 

), this criterion may be over conservative. 

ll This criterion has been revised to reflect the Environmental Protection Agency's cancer slope factor (CSF) or reference dose (RfD), as contained in the 

Integrated Risk Information System (IRIS) as of (Final FR Notice June 10, 2009). The fish tissue bioconcentration factor (BCF) from the 1980 Ambient Water 

Quality Criteria document was retained in each case. 

mm The available toxicity data, when evaluated using the procedures described in the “Guidelines for Deriving Numerical National Water Quality Criteria for 

the Protection of Aquatic Organisms and Their Uses” indicate that freshwater aquatic life should be protected if the 24-hour average and four-day average 

concentrations do not respectively exceed the acute and chronic criteria concentrations calculated by the Biotic Ligand Model.
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS

12

Non Priority Pollutants

Freshwater Saltwater Human Health for the 

consumption of

Non Priority Pollutant CAS

Number

CMC

(acut

e)

(μg/L

)

CCC

(chronic) 

(μg/L)

CMC

(acute) 

(μg/L)

CCC

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organis

m Only 

(μg/L)

FR Cite / Source

1 Alkalinity — 20000 

F 

Gold Book

2 Aluminum pH 6.5 – 9.0 7429905 750 

G,I 

87 

G,I,L 

53 FR 33178

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

SEE DOCUMENT D

SALTWATER CRITERIA ARE pH AND TEMPERATURE DEPENDENT 

EPA 822-R99-014

EPA 440-588-004

4 Aesthetic Qualities — NARRATIVE STATEMENT — SEE DOCUMENT Gold Book

5 Bacteria — FOR PRIMARY RECREATION AND SHELLFISH USES — SEE DOCUMENT Gold Book

6 Barium 7440393 1,000

A 

Gold Book

7 Boron — NARRATIVE STATEMENT — SEE DOCUMENT Gold Book

8 Chloride 16887006 86000

0 

G 

230000

G 

53 FR 19028

9 Chlorine 7782505 19 11 13 7.5 C Gold Book

10 Chlorophenoxy Herbicide 

(2,4,5,-TP) 

93721 10 

A 

Gold Book

11 Chlorophenoxy Herbicide 

(2,4-D) 

94757 100

A,C 

Gold Book

12 Chloropyrifos 2921882 0.083

G 

0.041

G 

0.011

G 

0.0056

G 

Gold Book

13 Color — NARRATIVE STATEMENT — SEE DOCUMENT F Gold Book

14 Demeton 8065483 0.1 F 0.1 F Gold Book

15 Ether, Bis( Chloromethyl) 542881 0.00010 

E,H 

0.00029 

E,H 

16

65 FR 66443 

Gases, Total Dissolved — NARRATIVE STATEMENT — SEE DOCUMENT F Gold Book
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS

13

Freshwater Saltwater Human Health for the 

consumption of

Non Priority Pollutant CAS

Number

CMC

(acut

e)

(μg/L

)

CCC

(chronic) 

(μg/L)

CMC

(acute) 

(μg/L)

CCC

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organis

m Only 

(μg/L)

FR Cite / Source

17 Guthion 86500 0.01

F 

0.01 

F

Gold Book

18 Hardness — NARRATIVE STATEMENT — SEE DOCUMENT Gold Book

19 Hexachlorocyclo-hexaneTechnical 608731 0.0123 

H 

0.0414

H 

EPA 440/5-80-054

20 Iron 7439896 1000 

F 

300 

A 

Gold Book

21 Malathion 121755 0.1 

F 

0.1 

F 

Gold Book

22 Manganese 7439965 50 

A,O 

100

A 

Gold Book

23 Methoxychlor 72435 0.03 

F

0.03 

F 

100 

A,C 

Gold Book

24 Mirex 2385855 0.001

F 

0.001 

F 

Gold Book

25 Nitrates 14797558 10,000 

A 

Gold Book

26 Nitrosamines — 0.0008 1.24 Gold Book

27 Dinitrophenols 25550587 69 5300 

28

65 FR 66443 

Nonylphenol 84852153 28ug/L 28ug/L 7ug/L 7ug/L 

29

71 FR 9337 

Nitrosodibutylamine, N 924163 0.0063 

A,H 

0.22 

A,H 

30

65 FR 66443 

Nitrosodiethylamine, N 55185 0.0008

A,H 

1.24 

A,H 

Gold Book

31 Nitrosopyrrolidine, N 930552 0.016

H 

34 

H 

32

65 FR 66443 

Oil and Grease — NARRATIVE STATEMENT — SEE DOCUMENT F Gold Book

33 Oxygen, Dissolved 

Freshwater Oxygen, 

Dissolved Saltwater 

7782447 WARMWATER AND COLDWATER MATRIX — SEE DOCUMENT N 

SALTWATER — SEE DOCUMENT 

Gold Book

EPA 822-R00-012

34 Diazinon 333415 0.17ug/L 0.17ug/L 0.82ug/L 0.82ug/L 71 FR 9336 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS

14

Freshwater Saltwater Human Health for the 

consumption of

Non Priority Pollutant CAS

Number

CMC

(acut

e)

(μg/L

)

CCC

(chronic) 

(μg/L)

CMC

(acute) 

(μg/L)

CCC

(chronic) 

(μg/L)

Water + 

Organism 

(μg/L)

Organis

m Only 

(μg/L)

FR Cite / Source

35 Parathion 56382 0.065 

J 

0.013 

J 

Gold Book

36 Pentachlorobenzene 608935 1.4 

E 

1.5 

E

37

65 FR 66443 

pH — 6.5 – 9 

F 

6.5 – 8.5

F,K 

5 – 9 Gold Book

38 Phosphorus Elemental 7723140 0.1

F,K 

Gold Book

39 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)

P

40 Solids Dissolved and 

Salinity 

— 250,000 

A 

Gold Book

41 Solids Suspended and

Turbidity 

— NARRATIVE STATEMENT—SEE DOCUMENT F Gold Book

42 Sulfide-Hydrogen Sulfide 7783064 2.0 

F 

2.0 

F 

Gold Book

43 Tainting Substances — NARRATIVE STATEMENT—SEE DOCUMENT Gold Book

44 Temperature — SPECIES DEPENDENT CRITERIA—SEE DOCUMENT M Gold Book

45 Tetrachlorobenzene,1,2,4,5 95943 0.97 

E 

1.1

E 

46

65 FR 66443 

Tributyltin (TBT) — 0.46 

Q 

0.072 

Q 

0.42 

Q 

0.0074 

Q 

47

69 FR 342 

Trichlorophenol,2,4,5 95954 1,800

B,E 

3,600 

B,E 

Footnotes

65 FR 66443 

A This human health criterion is the same as originally published in the Red Book (EPA 440/9-76-023, July, 1976) which predates the 1980 methodology and 

did not utilize the fish ingestion BCF approach. This same criterion value is now published in the Gold Book (Quality Criteria for Water: 1986. EPA 440/5-86-001).

B The organoleptic effect criterion is more stringent than the value presented in the non priority pollutants table. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS

15

C A more stringent Maximum Contaminant Level (MCL) has been issued by EPA under the Safe Drinking Water Act. Refer to drinking water regulations 

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 Aquatic Organisms and 

Their Uses, except possibly where a very sensitive species is important at a site, freshwater aquatic life should be protected if both conditions specified 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, 2002. The fish 

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 National Water Quality 

Criteria 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 440/5-88001); 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 level of 10-5, move 

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 Protection of Aquatic Life 

in Ambient Water (EPA 820-B-96-001). This value was derived using the GLI Guidelines (60 FR 15393-15399, March 23, 1995; 40CFR132 Appendix A); the 

differences between the 1985 Guidelines and the GLI Guidelines are explained on page iv of the 1995 Updates. No decision concerning this criterion was 

affected by any considerations that are specific to the Great Lakes. 

K According to page 181 of the Red Book (EPA 440/9-76-023, July, 1976): 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. 

L There are three major reasons why the use of Water-Effect Ratios might be appropriate. 

The value of 87 μg/l is based on a toxicity test with the striped 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, Middleway, West Virginia" (May 1994) indicate that aluminum is substantially less toxic at higher pH and hardness, 

but the effects of pH and hardness are not well quantified at this time. 

In tests with the brook trout at low pH and hardness, effects increased with increasing concentrations of total aluminum even though the concentration of 

dissolved aluminum was constant, indicating that total recoverable is a more appropriate measurement than dissolved, at least when particulate aluminum is 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS

16

primarily aluminum hydroxide particles. In surface waters, however, the total recoverable procedure might measure aluminum associated with clay particles, 

which might be less toxic than aluminum associated with aluminum hydroxide. 

EPA is aware of field data indicating that many high quality waters in the U.S. contain more than 87 g 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. EPA. 1977. Temperature 

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

N U.S. EPA. 1986. Ambient Water Quality Criteria for Dissolved Oxygen. EPA 440/5-86-003. 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 such as laundry stains and 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-01-010, VI EPA 822-B-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, XIII EPA 822-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 EPA 822-B-00-016, IV EPA 822-B-01-013, V EPA 822-B01-014, 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 822-B-01-016, XI EPA 822-B-00-020, XII EPA 

822-B-00-021, XIV EPA 822-B-00-022; and Wetlands in Nutrient Ecoregion (PDF) (77 pp., 257 K) XIII EPA 822-B-00-023. 

Q EPA announced the availability of a draft updated tributyltin (TBT) document on August 7, 1997 (62 FR 42554). The Agency has reevaluated this document 

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

17

Organoleptic Effects (e.g., taste and odor)

Pollutant CAS Number Organoleptic Effect Criteria

(μg/L) FR Cite/ Source

1 Acenaphthene 83329 20 Gold Book

2 Monochlorobenzene 108907 20 Gold Book

3 3-Chlorophenol — 0.1 Gold Book

4 4-Chlorophenol 106489 0.1 Gold Book

5 2,3-Dichlorophenol — 0.04 Gold Book

6 2,5-Dichlorophenol — 0.5 Gold Book

7 2,6-Dichlorophenol — 0.2 Gold Book

8 3,4-Dichlorophenol — 0.3 Gold Book

9 2,4,5-Trichlorophenol 95954 1 Gold Book

10 2,4,6-Trichlorophenol 88062 2 Gold Book

11 2,3,4,6-Tetrachlorophenol — 1 Gold Book

12 2-Methyl-4-Chlorophenol — 1800 Gold Book

13 3-Methyl-4-Chlorophenol 59507 3000 Gold Book

14 3-Methyl-6-Chlorophenol — 20 Gold Book

15 2-Chlorophenol 95578 0.1 Gold Book

16 Copper 7440508 1000 Gold Book

17 2,4-Dichlorophenol 120832 0.3 Gold Book

18 2,4-Dimethylphenol 105679 400 Gold Book

19 Hexachlorocyclopentadiene 77474 1 Gold Book

20 Nitrobenzene 98953 30 Gold Book

21 Pentachlorophenol 87865 30 Gold Book

22 Phenol 108952 300 Gold Book

23 Zinc 7440666 5000 45 FR79341

Notes

1. These criteria are based on organoleptic (taste and odor) effects. Because of variations in chemical nomenclature systems, this listing of pollutants does not 

duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service (CAS) registry numbers, which provide a unique 

identification for each chemical. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA

18

Additional 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 aquatic community 

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

concentration of a material in surface water to which an aquatic community can be exposed indefinitely without resulting in an unacceptable effect. 

The CMC and CCC are just two of the six parts of an aquatic life criterion; the other four parts are the acute averaging period, chronic averaging 

period, acute frequency of allowed exceedence, and chronic frequency of allowed exceedence. Because 304(a) aquatic life criteria are national 

guidance, they are intended to be protective of the vast 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 effect criteria 

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

pollutants not listed, CWA §304(a) "water + organism" human health criteria are not available, but EPA has published MCLs under the SDWA that 

may be used in establishing water quality standards to protect water supply designated uses. Because of variations in chemical nomenclature 

systems, this listing of toxic pollutants does not duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service 

CAS registry numbers, which provide 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 be obtained 

by 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 Section 303(c) 

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

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

freshwater metals' criteria that are not hardness-dependent are calculated by multiplying the total recoverable criteria before rounding by the 

appropriate conversion factors. The final dissolved metals' criteria in the table are rounded to two significant figures. Information regarding the 

calculation of hardness dependent conversion factors are included in the footnotes. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA

19

6. Maximum Contaminant Levels 

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

criteria in the 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 be accessed through the Safe Drinking Water Hotline (800-426-4791) or online. 

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 the non-toxicity 

based criteria are organoleptic effects (e.g., taste and odor) which would make water and edible aquatic life unpalatable but not toxic to humans. 

The table includes criteria for organoleptic effects for 23 pollutants. Pollutants with organoleptic effect criteria more stringent than the criteria based 

on toxicity (e.g., included in 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 CAS number for 

this 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 permit 

actions using the States' existing narrative criteria for toxics. 

11. Specific Chemical Calculations 

Selenium — Aquatic Life This compilation contains aquatic life criteria for selenium that are the same as those published in the proposed CTR. In the 

CTR, EPA proposed an acute criterion for selenium based on the criterion proposed for selenium in the Water Quality Guidance for the Great Lakes 

System (61 FR 58444). The GLI and CTR proposals take into account data showing that selenium's two prevalent oxidation states in water, selenite 

and selenate, present differing potentials for aquatic toxicity, as well as new data indicating that various forms of selenium are additive. The new 

approach produces a different selenium acute criterion 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 reassessment (63 FR 26186). However, until such time as revised water quality criteria for selenium are published by 

the Agency, the recommended water quality criteria in this compilation are EPA's current 304(a) criteria. 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA

20

Appendices

Appendix A — Conversion Factors for Dissolved Metals 

Metal

Conversion Factor

freshwater CMC freshwater CCC saltwater 

CMC

saltwater 

CCC1

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 VI 0.982 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 

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 

III 

0.8190 3.7256 0.8190 0.6848 0.316 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 0.8460 2.255 0.8460 0.0584 0.998 0.997 

Silver 1.72 -6.59 — — 0.85 —

Zinc 0.8473 0.884 0.8473 0.884 0.978 0.986 
NATIONAL RECOMMENDED WATER QUALITY CRITERIA

21

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)

Appendix C — Calculation of Freshwater Ammonia Criterion 

1. The one-hour average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three years on the average, the 

CMC (acute criterion) calculated using the following equations: 

• Where salmonid fish are present: 

CMC = (0.275/(1 + 107.204-pH)) + (39.0/(1 + 10pH-7.204)) 

• Or where salmonid fish are not present: 

CMC = (0.411/(1 + 107.204-pH)) + (58.4/(1 + 10pH-7.204)) 

2. A. 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: 

• CCC = ((0.0577/(1 + 107.688-pH)) + (2.487/(1 + 10pH-7.688))) x MIN (2.85, 1.45•100.028•(25-T)) 

• When fish early life stages are absent: 

• CCC = ((0.0577/(1 + 107.688-pH)) + (2.487/(1 + 10pH-7.688))) x 1.45•100.028•(25-MAX(T,7)) 

B. In addition, the highest four-day average within the 30-day period should not exceed 2.5 times the CCC.