26.08.02.03-2

.03-2 Numerical Criteria for Toxic Substances in Surface Waters.

A. Numerical toxic substance criteria shall be applied:

(1) In intermittent streams, at the end of the discharge pipe; and

(2) In all other water bodies, at the edge of the mixing zones determined in accordance with Regulation .05C—E of this chapter.

B. Acceptable laboratory methods for the detection and measurement of toxic substances shall be specified by the Department.

C. Site-specific numerical toxic substance criteria may be developed on a site-specific basis. A person who wishes to develop a site-specific numerical toxic substance criterion shall:

(1) Do so in accordance with a scientifically defensible methodology approved by the Department; and​

(2) Notify the Department of their intent not later than the time specified in COMAR 26.08.04.01-1.

D. The toxicity of certain substances in Tables 1 and 4 of §G of this regulation is increased or decreased by hardness or pH. For these toxic substances:

(1) The Department may:

(a) Require the discharger to provide site-specific measurements; or

(b) Recalculate the aquatic life criteria based on available water quality data.

(2) The permittee may voluntarily provide site-specific information for the recalculation of the criteria. It is within the Department's discretion to determine the weight given this information.

(3) After reviewing the information provided in §D(1) or (2), the Department shall determine if one or more of these criteria should be modified at a particular location.

(4) For calculation of site-specific copper criteria, a discharger may use the Biotic Ligand Model in accordance with "Aquatic Life Ambient Freshwater Quality Criteria-Copper 2007 Revision (EPA-822-R-07-001, February 2007)" which is incorporated by reference.

E. In those cases where numerical toxic substance criteria for aquatic life protection and protection of human health both apply, the most restrictive of the criteria shall be used.

F. Acute and chronic numeric toxic substance criteria for fresh, estuarine, and salt water aquatic life protection and for human health protection are shown in Tables 1—4 of §G. For the instream application of the acute and chronic criteria for the protection of aquatic life in Tables 1—4 of §G of this regulation:

(1) The metals shall be measured as dissolved metal or as biologically available equivalence and may be translated to total recoverable measurements for waste load allocation to derive discharge permit limits using the procedures for the biological translator or chemical translator described in COMAR 26.08.04;

(2) The organic substances shall be measured directly or as biologically available equivalence and may be translated for waste load allocation to derive discharge permit limits using the procedures for the biological translator described in COMAR 26.08.04; and

(3) Cyanide shall be measured as either free cyanide or cyanide amenable to chlorination.

G. Tables of Ambient Water Quality Criteria.

(1) Table 1. Toxic Substances Criteria for Ambient Surface Waters — Inorganic Substances.

Substance CAS# Aquatic Life (μg/L) Human Health for
Consumption of:
Fresh Water Estuarine
Water		 Salt Water Drinking Water
+
Organism
(μg/L)		 Organism
Only
(μg/L)		 Drinking
Water
MCL
(mg/L)
Acute Chronic Acute Chronic Acute Chronic
Antimony 7440360 5.6 640 0.006
Arsenic 7440382 340 150 69 36 0.18d 1.4a,d 0.010
Asbestos 1332214 7 million fibers/L 7 million fibers/L
Barium 7440393 1,000 2
Beryllium 4 0.004
Cadmium1 7440439 1.8 0.72 33.13 7.9 5 0.005
Chlorine2 7782505 19 11 13 7.5
Chromium
(total) 		7440473 100 0.1
Chromium III1 16065831 570 74
Chromium VI 18540299 16 11 1100 50
Copper1 7440508 13 9 6.1 4.8 3.1 1,300d 1.3c
Cyanide 57125 22 5.2 1 1 140 140 0.2
Lead1 7439921 65 2.5 210 8.1 0.015c
Mercury 7439976 1.4 0.77 1.8 0.94 0.002
Methylmercuryb 22967926 0.3 mg/kg in fish tissue
Nickel1 7440020 470 52 74 8.2 610 4,600
Selenium 7782492 20 5 290 71 170 4,200 0.05
Silver1 7440224 3.2 1.9 0.10
Thallium 7440280 0.24 0.47 0.002
Zinc1 7440666 120 120 90 81 7,400 26,000

1 Refer to §D of this regulation.

2 The more stringent of these criteria or the discharge requirements in COMAR 26.08.03.06 shall be used as the basis for determining discharge permit limitations.

a This criterion will be applied against the actual measurement of inorganic arsenic (As+3) rather than total arsenic.

b Per EPA recommendation, total mercury concentrations, as opposed to methylmercury, will be used in MDE fish consumption risk-calculation. This approach is deemed to be most protective of human health and most cost-effective.

c Lead and Copper are regulated by a treatment technique that requires systems to control the corrosiveness of their water. If more than 10 percent of tap water samples exceed the action level, water systems must take additional steps. The values listed are technically action levels.

d Criterion is based on a carcinogenic risk level of 10-5.

* Drinking water MCLs apply to Public Water Supply designated waters only.

(2) Table 2. Coefficients Used to Adjust Applicable Numerical Toxic Substance Fresh Water Aquatic Life Criteria. *

Substance CAS# mA bA mC bC
Cadmium 7440439 0.9789 -3.866 0.7977 -3.909
Chromium III 16065831 0.8190 3.7256 0.8190 0.6848
Lead 7439921 1.273 -1.460 1.273 -4.705
Nickel 7440020 0.8460 2.255 0.8460 0.0584
Silver 7440224 1.72 -6.59 - -
Zinc 7440666 0.8473 0.884 0.8473 0.884

(3) Table 3. Conversion Factors Used to Adjust Applicable Numerical Toxic Substance Fresh Water Aquatic Life Criteria.

Substance CAS# Freshwater Acute Conversion Factor (CF) Freshwater Chronic Conversion Factor (CF)
Cadmium 7440439 1.136672-LN(Hardness)*0.041838 1.101672-LN(Hardness)*0.041838
Chromium III 16065831 0.316 0.86
Lead 7439921 1.46203-LN(Hardness)*0.145712 1.46203-LN(Hardness)*0.145712
Nickel 7440020 0.998 0.997
Silver 7440224 0.85 -
Zinc 7440666 0.978 0.986

*Hardness-dependent criteria may be calculated from the following:

Acute Criteria = emA *LN(hardness)+bA*CF

Chronic Criteria = emC *LN(hardness)+bC*CF

(4) Table 4. Toxic Substances for Ambient Water Quality Criteria — Organic Compounds.

Substance CAS# Aquatic Life (μg/L) Human Health for
Consumption of:
Fresh Water Salt Water Drinking Water
+
Organism
(μg/L)		 Organism
Only
(μg/L)		 Drinking
Water
MCL
(mg/L)
Acute Chronic Acute Chronic
1,1 Dichloroethylene (DCE) 75354 300 20000 0.007
1,1,1-Trichloroethane (TCA) 71556 200 0.2
1,1,2,2-Tetrachloroethane 79345 1.7a 40a
1,1,2-Trichloroethane 79005 5.9a 160a 0.005
1,2,4-Trichlorobenzene 120821 35a 70a 0.07
1,2,4,5-Tetrachlorobenzene 95943 0.03 0.03
1,2-Dichlorobenzene 95501 1000 3000 0.6
1,2-Dichloroethane 107062 99a 6500a 0.005
1,2-Dichloropropane 78875 5a 150a 0.005
1,2-Diphenylhydrazine 122667 0.3a 2a
1,2-Trans-Dichloroethylene 156605 100 4000 0.1
1,3-Dichlorobenzene 541731 320 960
1,3-Dichloropropene 542756 3.4a 210a
1,4-Dichlorobenzene 106467 300 900 0.075
2,4,5-Trichlorophenol 95954 300 600
2,4,6-Trichlorophenol 88062 14a 24a
2,4-Dichlorophenol 120832 77 290
2,4-Dimethylphenol 105679 100 3000
2,4-Dinitrotoluene 121142 1.1a 34a
2-Chloronapthalene 91587 800 1000
2-Chlorophenol 95578 81 150
2-Methyl-4,6-Dinitrophenol 534521 2 30
3,3'-Dichlorobenzidine 91941 0.49a 1.5a
3-Methyl-4-Chlorophenol 59507 500 2000
Acrolein 107028 3 3 6 9
Acrylonitrile 107131 0.61a 70a
Benzene 71432 22a 510a 0.005
Benzidine 92875 0.0014a 0.11a
Bis(2-Chloroethyl) Ether 111444 0.3a 22a
Bis2(Chloroisopropyl) Ether 108601 200
 4000
Bis(Chloromethyl) Ether 542881 0.0015a 0.17a
Bromoform1 75252 See
Trihalomethanes 		1400a
Carbon tetrachloride 56235 4a 50a 0.005
Chlorobenzene 108907 130 1600 0.1
Chlorodibromomethane1 124481 8a 210a
Chloroform1 67663 60 2000
Chlorophenoxy Herbicide (2,4-D) 94757 1300 12000
Chlorophenoxy Herbicide (2,4,5-TP) 93721 100 400
Dichlorobromomethane1 75274 See
Trihalomethanes 		170a
Dinitrophenols 25550587 10 1000
Ethylbenzene 100414 530 2100 0.7
Hexachlorobenzene 118741 0.00079a 0.00079a 0.001
Hexachlorobutadiene 87683 4.4a 180a
Hexachlorocyclopenta-diene 77474 4 4 0.05
Hexachloroethane 67721 14a 33a
Hexachlorocyclohexane (HCH)-Technical 608731 0.066a 0.1a
Isophorone 78591 340a 18000a
Methoxychlor 72435 0.02 0.02
Methyl bromide 74839 100 10000
Methylene chloride 75092 200a 10000a 0.005
Nitrobenzene 98953 10 600
N-Nitrosodimethylamine 62759 0.0069a 30 a
N-Nitrosodi-n-Propylamine 621647 0.05a 5.1a
N-Nitrosodiphenylamine 86306 33a 60a
Nonylphenol 84852153 28 6.6 7 1.7
Phenol 108952 4000 300000
Tetrachloroethylene 127184 100a 290a 0.005
Toluene 108883 1300 15000 1
Trichloroethylene (TCE) 79016 6a 70a 0.005
Trihalomethanes1 80 0.08
Vinyl chloride 75014 0.22a 16a 0.002

1 Four compounds (bromoform, chlorodibromomethane, chloroform, and dichlorobromomethane) are found in combination and comprise a category of contaminants called "trihalomethanes" formed as a result of drinking water disinfection. The concentration of any of these compounds individually, or all of them in sum, may not exceed 80 micrograms per liter. This criterion is equal to the Safe Drinking Water Act Maximum Contaminant Level.

a Criterion is based on a carcinogenic risk level of 10-5.

* Drinking water MCLs apply to Public Water Supply designated waters only.

(5) Table 5. Toxic Substances for Ambient Water Quality Criteria-Polycyclic Aromatic Hydrocarbons and Phthalates.

Substance CAS#
 Aquatic Life (μg/L) Human Health for
Consumption of:
Fresh Water Salt Water Drinking Water
+
Organism
(μg/L)		 Organism
Only
(μg/L)		 Drinking
Water
MCL
(mg/L)
Acute Chronic Acute Chronic
Acenaphthene 83329 70 90
Anthracene 120127 300 400
Benzo(a)Anthracene 56553 0.012a 0.013a
Benzo(a)Pyrene 50328 0.0012a 0.0013a 0.0002
Benzo(b)Fluoranthene 205992 0.012a 0.013a
Benzo(k)Fluoranthene 207089 0.12a 0.13a
Chrysene 218019 0.038a 0.18a
Dibenzo(a,h)Anthracene 53703 0.0012a 0.0013a
Fluoranthene 206440 20 20
Fluorene 86737 50 70
Ideno(1,2,3-cd)Pyrene 193395 0.012a 0.013a
Pyrene 129000 20 30
Bis(2-Ethylhexyl) Phthalate 117817 3.2a 3.7a 0.006
Butylbenzyl Phthalate 85687 1a 1a
Diethyl Phthalate 84662 600 600
Dimethyl Phthalate 131113 2000 2000
Di-n-Butyl Phthalate 84742 20 30

a Criterion is based on a carcinogenic risk level of 10-5.

* Drinking water MCLs apply to Public Water Supply designated waters only.

(6) Table 6. Toxic Substances for Ambient Water Quality Criteria — Pesticides and Chlorinated Compounds.

Substance CAS#
 Aquatic Life (μg/L) Human Health for
Consumption of:
Fresh Water Salt Water Drinking Water
+
Organism
(μg/L)		 Organism
Only
(μg/L)		 Drinking
Water
MCL
(mg/L)
Acute Chronic Acute Chronic
2, 3, 7, 8-TCDD (Dioxin) 1746016 0.00000005a 0.00000051a 3 * 10-8
4,4'-DDD 72548 0.0012a 0.0012a
4,4'-DDE 72559 0.00018a 0.00018a
4,4'-DDT 50293 1.1 0.001 0.13 0.001 0.0003a 0.0003a
Aldrin 309002 3 1.3 0.0000077a 0.0000077a
alpha-BHC 319846 0.0036a 0.0039a
alpha-Endosulfan 959988 0.22 0.056 0.034 0.0087 20 30
Atrazine 1912249 3 0.003
beta-BHC 319857 0.08a 0.14a
beta-Endosulfan 33213659 0.22 0.056 0.034 0.0087 20 40
Carbaryl 63252 2.1 2.1 1.6        
Chlordane 57749 2.4 0.0043 0.09 0.004 0.0031a 0.0032a 0.002
Chlorpyrifos 2921882 0.083 0.041 0.011 0.0056
Diazinon 333415 0.17 0.17 0.82 0.82      
Dieldrin 60571 0.24 0.056 0.71 0.0019 0.000012a 0.000012a
Endosulfan Sulfate 1031078 20 40
Endrin 72208 0.086 0.036 0.037 0.0023 0.059 0.060 0.002
Endrin Aldehyde 7421934 1 1
gamma-BHC (Lindane) 58899 0.95 0.16 4.2 4.4 0.0002
Heptachlor 76448 0.52 0.0038 0.053 0.0036 0.000059a 0.000059a 0.0004
Heptachlor Epoxide 1024573 0.52 0.0038 0.053 0.0036 0.00032a 0.00032a 0.0002
Polychlorinated Biphenyls PCBs 0.014 0.03 0.00064a 0.00064a 0.0005
Toxaphene 8001352 0.73 0.002 0.21 0.002 0.007a 0.0071a 0.003
Tributyltin (TBT) 0.46 0.072 0.42 0.0074
Pentachlorobenzene 608935 0.1 0.1
Pentachlorophenol (PCP) 87865 19 15 13 7.9 2.7a 30a 0.001

a Criterion is based on a carcinogenic risk level of 10-5.

* Drinking water MCLs apply to Public Water Supply designated waters only.

H. Acute Numeric Toxic Substance Criteria for Ammonia for the Protection of Fresh Water Aquatic Life.

(1) The use of Tables 3 and 4 requires documentation acceptable to the Department of the absence of freshwater mussels using the methods outlined in the document "Procedures for Applying the Mussel-Absent Ammonia Criteria to Maryland Surface Waters", which is incorporated by reference.

(2) Presence of Salmonid Fish. In Class III, III-P, IV, and IV-P waters, the concentration of total ammonia (in milligrams of nitrogen per liter) may not exceed the acute criterion listed in Table 1.

(3) Absence of Salmonid Fish. In Class I and I-P waters, the concentration of total ammonia (in milligrams of nitrogen per liter) may not exceed the acute criterion listed in Table 2.

(4) Presence of Salmonid Fish and Absence of Freshwater Mussels. In Class III, III-P, IV, and IV-P waters, the concentration of total ammonia (in milligrams of nitrogen per liter) may not exceed the acute criterion listed in Table 3.

(5) Absence of Salmonid Fish and Absence of Freshwater Mussels. In Class I and I-P waters, the concentration of total ammonia (in milligrams of nitrogen per liter) may not exceed the acute criterion listed in Table 4.

(6) Table 1. Acute Water Quality Criteria for Freshwater Aquatic Life for Ammonia Where Salmonids May Be Present (milligrams of nitrogen per liter)1.

Temperature (oC)
pH 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 32.6 32.6 31.6 29.1 26.8 24.6 22.7 20.9 19.2 17.7 16.3 15.0 13.8 12.7 11.7 10.8 9.9
6.6 31.3 31.3 30.3 27.9 25.7 23.6 21.8 20.0 18.4 17.0 15.6 14.4 13.2 12.2 11.2 10.3 9.5
6.7 29.8 29.8 28.8 26.5 24.4 22.5 20.7 19.0 17.5 16.1 14.9 13.7 12.6 11.6 10.7 9.8 9.0
6.8 28.0 28.0 27.2 25.0 23.0 21.2 19.5 18.0 16.5 15.2 14.0 12.9 11.9 10.9 10.0 9.2 8.5
6.9 26.2 26.2 25.3 23.3 21.5 19.8 18.2 16.7 15.4 14.2 13.1 12.0 11.1 10.2 9.4 8.6 7.9
7.0 24.1 24.1 23.3 21.5 19.8 18.2 16.8 15.4 14.2 13.1 12.0 11.1 10.2 9.4 8.6 7.9 7.3
7.1 21.9 21.9 21.3 19.6 18.0 16.6 15.3 14.0 12.9 11.9 11.0 10.1 9.3 8.5 7.9 7.2 6.7
7.2 19.7 19.7 19.1 17.6 16.2 14.9 13.7 12.6 11.6 10.7 9.8 9.1 8.3 7.7 7.1 6.5 6.0
7.3 17.5 17.5 17.0 15.6 14.4 13.2 12.2 11.2 10.3 9.5 8.7 8.0 7.4 6.8 6.3 5.8 5.3
7.4 15.3 15.3 14.9 13.7 12.6 11.6 10.7 9.8 9.0 8.3 7.7 7.0 6.5 6.0 5.5 5.1 4.7
7.5 13.3 13.3 12.9 11.8 10.9 10.0 9.2 8.5 7.8 7.2 6.6 6.1 5.6 5.2 4.8 4.4 4.0
7.6 11.4 11.4 11.0 10.1 9.3 8.6 7.9 7.3 6.7 6.2 5.7 5.2 4.8 4.4 4.1 3.8 3.5
7.7 9.6 9.6 9.3 8.6 7.9 7.3 6.7 6.2 5.7 5.2 4.8 4.4 4.1 3.8 3.5 3.2 2.9
7.8 8.1 8.1 7.9 7.2 6.7 6.1 5.6 5.2 4.8 4.4 4.0 3.7 3.4 3.2 2.9 2.7 2.5
7.9 6.8 6.8 6.6 6.0 5.6 5.1 4.7 4.3 4.0 3.7 3.4 3.1 2.9 2.6 2.4 2.2 2.1
8.0 5.6 5.6 5.4 5.0 4.6 4.2 3.9 3.6 3.3 3.0 2.8 2.6 2.4 2.2 2.0 1.9 1.7
8.1 4.6 4.6 4.5 4.1 3.8 3.5 3.2 3.0 2.7 2.5 2.3 2.1 2.0 1.8 1.7 1.5 1.4
8.2 3.8 3.8 3.7 3.4 3.1 2.9 2.7 2.4 2.3 2.1 1.9 1.8 1.6 1.5 1.4 1.3 1.2
8.3 3.1 3.1 3.1 2.8 2.6 2.4 2.2 2.0 1.9 1.7 1.6 1.4 1.3 1.2 1.1 1.0 1.0
8.4 2.6 2.6 2.5 2.3 2.1 2.0 1.8 1.7 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8
8.5 2.1 2.1 2.1 1.9 1.8 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.8 0.7 0.6
8.6 1.8 1.8 1.7 1.6 1.5 1.3 1.2 1.1 1.0 1.0 0.9 0.8 0.7 0.7 0.6 0.6 0.5
8.7 1.5 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4
8.8 1.2 1.2 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4
8.9 1.0 1.0 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.3 0.3
9.0 0.9 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.3 0.3 0.3 0.3

1 The acute water quality criteria for total ammonia where salmonids may be present was calculated using the following equation, which may also be used to calculate unlisted values: Acute water quality criteria for ammonia (salmonids present) =

 

Where MIN indicates the lesser of the two values separated by a comma.

(7) Table 2. Acute Water Quality Criteria for Freshwater Aquatic Life for Ammonia Where Salmonids Are Absent (milligrams of nitrogen per liter)1.

Temperature (℃)
pH 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 50.9 47.8 44.0 40.5 37.3 34.3 31.6 29.1 26.8 24.6 22.7 20.9 19.2 17.7 16.3 15.0 13.8 12.7 11.7 10.8 9.9
6.6 48.9 45.9 42.2 38.9 35.8 32.9 30.3 27.9 25.7 23.6 21.8 20.0 18.4 17.0 15.6 14.4 13.2 12.2 11.2 10.3 9.5
6.7 46.5 43.6 40.2 37.0 34.0 31.3 28.8 26.5 24.4 22.5 20.7 19.0 17.5 16.1 14.9 13.7 12.6 11.6 10.7 9.8 9.0
6.8 43.8 41.1 37.9 34.8 32.1 29.5 27.2 25.0 23.0 21.2 19.5 18.0 16.5 15.2 14.0 12.9 11.9 10.9 10.0 9.2 8.5
6.9 40.8 38.3 35.3 32.5 29.9 27.5 25.3 23.3 21.5 19.8 18.2 16.7 15.4 14.2 13.1 12.0 11.1 10.2 9.4 8.6 7.9
7.0 37.6 35.3 32.5 29.9 27.6 25.4 23.3 21.5 19.8 18.2 16.8 15.4 14.2 13.1 12.0 11.1 10.2 9.4 8.6 7.9 7.3
7.1 34.3 32.2 29.6 27.3 25.1 23.1 21.3 19.6 18.0 16.6 15.3 14.0 12.9 11.9 11.0 10.1 9.3 8.5 7.9 7.2 6.7
7.2 30.8 28.9 26.6 24.5 22.6 20.8 19.1 17.6 16.2 14.9 13.7 12.6 11.6 10.7 9.8 9.1 8.3 7.7 7.1 6.5 6.0
7.3 27.3 25.7 23.6 21.7 20.0 18.4 17.0 15.6 14.4 13.2 12.2 11.2 10.3 9.5 8.7 8.0 7.4 6.8 6.3 5.8 5.3
7.4 24.0 22.5 20.7 19.1 17.5 16.1 14.9 13.7 12.6 11.6 10.7 9.8 9.0 8.3 7.7 7.0 6.5 6.0 5.5 5.1 4.7
7.5 20.7 19.5 17.9 16.5 15.2 14.0 12.9 11.8 10.9 10.0 9.2 8.5 7.8 7.2 6.6 6.1 5.6 5.2 4.8 4.4 4.0
7.6 17.8 16.7 15.4 14.1 13.0 12.0 11.0 10.1 9.3 8.6 7.9 7.3 6.7 6.2 5.7 5.2 4.8 4.4 4.1 3.8 3.5
7.7 15.1 14.1 13.0 12.0 11.0 10.1 9.3 8.6 7.9 7.3 6.7 6.2 5.7 5.2 4.8 4.4 4.1 3.8 3.5 3.2 2.9
7.8 12.7 11.9 10.9 10.1 9.3 8.5 7.9 7.2 6.7 6.1 5.6 5.2 4.8 4.4 4.0 3.7 3.4 3.2 2.9 2.7 2.5
7.9 10.6 9.9 9.1 8.4 7.7 7.1 6.6 6.0 5.6 5.1 4.7 4.3 4.0 3.7 3.4 3.1 2.9 2.6 2.4 2.2 2.1
8.0 8.8 8.2 7.6 7.0 6.4 5.9 5.4 5.0 4.6 4.2 3.9 3.6 3.3 3.0 2.8 2.6 2.4 2.2 2.0 1.9 1.7
8.1 7.2 6.8 6.3 5.8 5.3 4.9 4.5 4.1 3.8 3.5 3.2 3.0 2.7 2.5 2.3 2.1 2.0 1.8 1.7 1.5 1.4
8.2 6.0 5.6 5.2 4.8 4.4 4.0 3.7 3.4 3.1 2.9 2.7 2.4 2.3 2.1 1.9 1.8 1.6 1.5 1.4 1.3 1.2
8.3 4.9 4.6 4.2 3.9 3.6 3.3 3.1 2.8 2.6 2.4 2.2 2.0 1.9 1.7 1.6 1.4 1.3 1.2 1.1 1.0 1.0
8.4 4.1 3.8 3.5 3.2 3.0 2.7 2.5 2.3 2.1 2.0 1.8 1.7 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8
8.5 3.3 3.1 2.9 2.7 2.4 2.3 2.1 1.9 1.8 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.8 0.7 0.6
8.6 2.8 2.6 2.4 2.2 2.0 1.9 1.7 1.6 1.5 1.3 1.2 1.1 1.0 1.0 0.9 0.8 0.7 0.7 0.6 0.6 0.5
8.7 2.3 2.2 2.0 1.8 1.7 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4
8.8 1.9 1.8 1.7 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4
8.9 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.3 0.3
9.0 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.3 0.3 0.3 0.3

1 The acute water quality criteria for total ammonia where salmonids are absent were calculated using the following equation, which may also be used to calculate unlisted values: Acute water quality criteria for ammonia (salmonids absent) =

 

Where MIN indicates the lesser of the two values separated by a comma.

(8) Table 3. Acute Water Quality Criteria for Freshwater Aquatic Life for Ammonia Where Salmonids May Be Present and Freshwater Mussels Are Absent (milligrams of nitrogen per liter)1.

Temperature (o C)
pH 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 31.4 28.9 26.6
6.6 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 31.3 30.1 27.7 25.5
6.7 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 29.8 28.7 26.4 24.3
6.8 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 28.0 27.0 24.9 22.9
6.9 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 26.2 25.2 23.2 21.3
7.0 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 23.2 21.4 19.7
7.1 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.9 21.1 19.5 17.9
7.2 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.7 19.0 17.5 16.1
7.3 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 16.9 15.5 14.3
7.4 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 15.3 14.8 13.6 12.5
7.5 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 12.8 11.8 10.8
7.6 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.4 11.0 10.1 9.3
7.7 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.3 8.5 7.9
7.8 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 8.1 7.8 7.2 6.6
7.9 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.5 6.0 5.5
8.0 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.6 5.4 5.0 4.6
8.1 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.6 4.5 4.1 3.8
8.2 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.7 3.4 3.1
8.3 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.1 3.0 2.8 2.6
8.4 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.5 2.3 2.1
8.5 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 1.9 1.7
8.6 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.7 1.6 1.4
8.7 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.4 1.3 1.2
8.8 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.1 1.0
8.9 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.9 0.8
9.0 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.7

1 The acute water quality criteria for total ammonia where salmonids are present and freshwater mussels are absent were calculated using the following equation, which may also be used to calculate unlisted values: Acute water quality criteria for ammonia (salmonids present and freshwater mussels absent) =CMC=

 

Where MIN indicates the lesser of the two values separated by a comma.

(9) Table 4. Acute Water Quality Criteria for Freshwater Aquatic Life for Ammonia Where Salmonids Are Absent and Freshwater Mussels Are Absent (milligrams of nitrogen per liter)1.

Temperature (o C)
pH 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 50.9 50.9 50.9 50.9 50.9 50.9 50.9 50.9 50.9 47.5 43.8 40.3 37.1 34.1 31.4 28.9 26.6
6.6 48.9 48.9 48.9 48.9 48.9 48.9 48.9 48.9 48.9 45.6 42.0 38.6 35.6 32.7 30.1 27.7 25.5
6.7 46.5 46.5 46.5 46.5 46.5 46.5 46.5 46.5 46.5 43.4 39.9 36.8 33.8 31.1 28.7 26.4 24.3
6.8 43.8 43.8 43.8 43.8 43.8 43.8 43.8 43.8 43.8 40.9 37.6 34.6 31.9 29.3 27.0 24.9 22.9
6.9 40.8 40.8 40.8 40.8 40.8 40.8 40.8 40.8 40.8 38.1 35.1 32.3 29.7 27.4 25.2 23.2 21.3
7.0 37.6 37.6 37.6 37.6 37.6 37.6 37.6 37.6 37.6 35.1 32.3 29.8 27.4 25.2 23.2 21.4 19.7
7.1 34.3 34.3 34.3 34.3 34.3 34.3 34.3 34.3 34.3 32.0 29.4 27.1 24.9 23.0 21.1 19.5 17.9
7.2 30.8 30.8 30.8 30.8 30.8 30.8 30.8 30.8 30.8 28.8 26.5 24.4 22.4 20.6 19.0 17.5 16.1
7.3 27.3 27.3 27.3 27.3 27.3 27.3 27.3 27.3 27.3 25.5 23.5 21.6 19.9 18.3 16.9 15.5 14.3
7.4 24.0 24.0 24.0 24.0 24.0 24.0 24.0 24.0 24.0 22.4 20.6 18.9 17.4 16.1 14.8 13.6 12.5
7.5 20.7 20.7 20.7 20.7 20.7 20.7 20.7 20.7 20.7 19.4 17.8 16.4 15.1 13.9 12.8 11.8 10.8
7.6 17.8 17.8 17.8 17.8 17.8 17.8 17.8 17.8 17.8 16.6 15.3 14.0 12.9 11.9 11.0 10.1 9.3
7.7 15.1 15.1 15.1 15.1 15.1 15.1 15.1 15.1 15.1 14.1 12.9 11.9 11.0 10.1 9.3 8.5 7.9
7.8 12.7 12.7 12.7 12.7 12.7 12.7 12.7 12.7 12.7 11.8 10.9 10.0 9.2 8.5 7.8 7.2 6.6
7.9 10.6 10.6 10.6 10.6 10.6 10.6 10.6 10.6 10.6 9.9 9.1 8.4 7.7 7.1 6.5 6.0 5.5
8.0 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.2 7.5 6.9 6.4 5.9 5.4 5.0 4.6
8.1 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 6.8 6.2 5.7 5.3 4.9 4.5 4.1 3.8
8.2 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 5.6 5.1 4.7 4.3 4.0 3.7 3.4 3.1
8.3 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.6 4.2 3.9 3.6 3.3 3.0 2.8 2.6
8.4 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 3.8 3.5 3.2 2.9 2.7 2.5 2.3 2.1
8.5 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.1 2.9 2.6 2.4 2.2 2.1 1.9 1.7
8.6 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.6 2.4 2.2 2.0 1.9 1.7 1.6 1.4
8.7 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.1 2.0 1.8 1.7 1.5 1.4 1.3 1.2
8.8 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.8 1.7 1.5 1.4 1.3 1.2 1.1 1.0
8.9 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8
9.0 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.3 1.2 1.1 1.0 0.9 0.9 0.8 0.7

1 The acute water quality criteria for total ammonia where salmonids are absent and freshwater mussels are absent were calculated using the following equation, which may also be used to calculate unlisted values: Acute water quality criteria for ammonia (salmonids absent and freshwater mussels absent) = CMC=

​

Where MIN indicates the lesser of the two values separated by a comma.

I. Chronic Numeric Toxic Substance Criteria for Ammonia, Expressed as a 30-day Average, for the Protection of Fresh Water Aquatic Life.

(1) Averaging Period. The concentration of total ammonia nitrogen (in milligrams of nitrogen per liter) expressed as a 30-day average may not exceed the chronic criterion listed in Tables 1, 2 or 3.

(2) The use of Table 3 requires documentation acceptable to the Department of the absence of fish early life stages.

(3) The use of Table 2 or 3 requires documentation acceptable to the Department of the absence of freshwater mussels using the methods outlined in the document Procedures for Applying Mussel-Absent Ammonia Criteria to Maryland Surface Waters.

(4) In addition, the highest 4-day average within the 30-day period may not exceed 2.5 times the chronic criterion.

(5) Table 1. Chronic Ammonia Criteria for Waters Where Freshwater Fish Early Life Stages May Be Present (milligrams of nitrogen per liter).1

​ Temperature (℃)
pH 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 4.9
 4.6
 4.3 4.0 3.8 3.6 3.3 3.1 2.9 2.8 2.6 2.4 2.3 2.1 2.0 1.9 1.8 1.6 1.5 1.4 1.4 1.3 1.2 1.1
6.6 4.8
 4.5
 4.3 4.0 3.7 3.5 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 2.0 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1
6.7 4.7
 4.4
 4.2 3.9 3.7 3.4 3.2 3.0 2.8 2.7 2.5 2.3 2.2 2.1 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1
6.8 4.6
 4.3
 4.1 3.8 3.6 3.4 3.1 3.0 2.8 2.6 2.4 2.3 2.1 2.0 1.9 1.8 1.7 1.5 1.5 1.4 1.3 1.2 1.1 1.1
6.9 4.5
 4.2​
 4.0 3.7 3.5 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1 1.0
7 4.3
 4.1
 3.8 3.6 3.4 3.1 2.9 2.8 2.6 2.4 2.3 2.1 2.0 1.9 1.8 1.7 1.5 1.5 1.4 1.3 1.2 1.1 1.1 1.0
7.1 4.2
 3.9
 3.7 3.4 3.2 3.0 2.8 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9
7.2 3.9
 3.7
 3.5 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9
7.3 3.7
 3.5
 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9 0.8
7.4 3.5
 3.2
 3.0 2.8 2.7 2.5 2.3 2.2 2.1 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9 0.8 0.8
7.5 3.2
 3.0
 2.8 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7
7.6 2.9
 2.7
 2.5 2.4 2.2 2.1 2.0 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9 0.8 0.8 0.7 0.7 0.7
7.7 2.6
 2.4
 2.3 2.1 2.0 1.9 1.8 1.6 1.5 1.4 1.4 1.3 1.2 1.1 1.0 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6
7.8 2.3
 2.1
 2.0 1.9 1.8 1.7 1.5 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5
7.9 2.0
 1.9
 1.7 1.6 1.5 1.4 1.4 1.3 1.2 1.1 1.0 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.5
8 1.7
 1.6
 1.5 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9 0.8 0.8 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4
8.1 1.5
 1.4
 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3
8.2 1.2
 1.2
 1.1 1.0 1.0 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3
8.3 1.0
 1.0
 0.9 0.8 0.8 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.2 0.2
8.4 0.9
 0.8
 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.2
8.5 0.7
 0.7
 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
8.6 0.6
 0.5
 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1
8.7 0.5
 0.4
 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1
8.8 0.4
 0.4
 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
8.9 0.3
 0.3
 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
9 0.2
 0.2
 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

1 The freshwater chronic water quality criteria for total ammonia where fish early life stages may be present were calculated using the following equation, which may also be used to calculate unlisted values:

Freshwater chronic water quality criterion for ammonia (fish early life stages present) =


Where MIN indicates the lesser of the two values separated by a comma.

(6) Table 2. Chronic Ammonia Criteria for Waters Where Freshwater Fish Early Life Stages Are Present and Freshwater mussels are absent (milligrams of nitrogen per liter).1

Temperature(℃)
pH

 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.0 6.6 6.2 5.8 5.4 5.1 4.8 4.5 4.2
6.6 7.2 7.2 7.2 7.2 7.2 7.2 7.2 7.2 6.9 6.5 6.1 5.7 5.3 5.0 4.7 4.4 4.1
6.7 7.1 7.1 7.1 7.1 7.1 7.1 7.1 7.1 6.8 6.4 6.0 5.6 5.2 4.9 4.6 4.3 4.1
6.8 6.9 6.9 6.9 6.9 6.9 6.9 6.9 6.9 6.6 6.2 5.8 5.5 5.1 4.8 4.5 4.2 4.0
6.9 6.7 6.7 6.7 6.7 6.7 6.7 6.7 6.7 6.4 6.0 5.7 5.3 5.0 4.7 4.4 4.1 3.8
7 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.2 5.8 5.5 5.1 4.8 4.5 4.2 4.0 3.7
7.1 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 5.9 5.6 5.2 4.9 4.6 4.3 4.0 3.8 3.6
7.2 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.6 5.3 5.0 4.7 4.4 4.1 3.8 3.6 3.4
7.3 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.3 5.0 4.7 4.4 4.1 3.8 3.6 3.4 3.2
7.4 5.2 5.2 5.2 5.2 5.2 5.2 5.2 5.2 4.9 4.6 4.3 4.1 3.8 3.6 3.4 3.1 2.9
7.5 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.5 4.3 4.0 3.7 3.5 3.3 3.1 2.9 2.7
7.6 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.1 3.9 3.6 3.4 3.2 3.0 2.8 2.6 2.5
7.7 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.7 3.5 3.2 3.0 2.9 2.7 2.5 2.3 2.2
7.8 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 1.9
7.9 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 2.8 2.7 2.5 2.3 2.2 2.1 1.9 1.8 1.7
8 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5
8.1 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.1 2.0 1.8 1.7 1.6 1.5 1.4 1.3 1.2
8.2 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.7 1.5 1.5 1.4 1.3 1.2 1.1 1.1
8.3 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9
8.4 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7
8.5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6
8.6 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5 0.5
8.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.5 0.4 0.4
8.8 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3
8.9 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3
9 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2

1The freshwater chronic water quality criteria for total ammonia where fish early life stages are present but freshwater mussels are absent were calculated using the following equation, which may also be used to calculate unlisted values:

Freshwater chronic water quality criterion for ammonia (fish early life stages present and freshwater mussels absent) = CCC=​


Where MIN indicates the lesser of the two values separated by a comma.

(7) Table 3. Chronic Ammonia Criteria for Waters Where Freshwater Fish Early Life Stages Are Absent and Freshwater Mussels Are Absent (milligrams of nitrogen per liter).1

Temperature (oC)
pH 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
6.5 18.5 17.3 16.2 15.2 14.3 13.4 12.6 11.8 11.0 10.3 9.7 9.1 8.5 8.0 7.5 7.0 6.6 6.2 5.8 5.4 5.1 4.8 4.5 4.2
6.6 18.2 17.1 16.0 15.0 14.1 13.2 12.4 11.6 10.9 10.2 9.6 9.0 8.4 7.9 7.4 6.9 6.5 6.1 5.7 5.3 5.0 4.7 4.4 4.1
6.7 17.8 16.7 15.7 14.7 13.8 12.9 12.1 11.4 10.7 10.0 9.4 8.8 8.2 7.7 7.2 6.8 6.4 6.0 5.6 5.2 4.9 4.6 4.3 4.1
6.8 17.4 16.3 15.3 14.4 13.5 12.6 11.8 11.1 10.4 9.8 9.1 8.6 8.0 7.5 7.1 6.6 6.2 5.8 5.5 5.1 4.8 4.5 4.2 4.0
6.9 16.9 15.9 14.9 13.9 13.1 12.3 11.5 10.8 10.1 9.5 8.9 8.3 7.8 7.3 6.9 6.4 6.0 5.7 5.3 5.0 4.7 4.4 4.1 3.8
7 16.3 15.3 14.4 13.5 12.6 11.8 11.1 10.4 9.8 9.1 8.6 8.0 7.5 7.1 6.6 6.2 5.8 5.5 5.1 4.8 4.5 4.2 4.0 3.7
7.1 15.6 14.7 13.8 12.9 12.1 11.3 10.6 10.0 9.3 8.8 8.2 7.7 7.2 6.8 6.3 5.9 5.6 5.2 4.9 4.6 4.3 4.0 3.8 3.6
7.2 14.9 13.9 13.1 12.2 11.5 10.8 10.1 9.5 8.9 8.3 7.8 7.3 6.9 6.4 6.0 5.6 5.3 5.0 4.7 4.4 4.1 3.8 3.6 3.4
7.3 14.0 13.1 12.3 11.5 10.8 10.1 9.5 8.9 8.3 7.8 7.3 6.9 6.4 6.0 5.7 5.3 5.0 4.7 4.4 4.1 3.8 3.6 3.4 3.2
7.4 13.0 12.2 11.4 10.7 10.0 9.4 8.8 8.3 7.8 7.3 6.8 6.4 6.0 5.6 5.3 4.9 4.6 4.3 4.1 3.8 3.6 3.4 3.1 2.9
7.5 11.9 11.2 10.5 9.8 9.2 8.6 8.1 7.6 7.1 6.7 6.3 5.9 5.5 5.2 4.8 4.5 4.3 4.0 3.7 3.5 3.3 3.1 2.9 2.7
7.6 10.8 10.2 9.5 8.9 8.4 7.8 7.4 6.9 6.5 6.1 5.7 5.3 5.0 4.7 4.4 4.1 3.9 3.6 3.4 3.2 3.0 2.8 2.6 2.5
7.7 9.7 9.1 8.5 8.0 7.5 7.0 6.6 6.2 5.8 5.4 5.1 4.8 4.5 4.2 3.9 3.7 3.5 3.2 3.0 2.9 2.7 2.5 2.3 2.2
7.8 8.6 8.0 7.5 7.1 6.6 6.2 5.8 5.5 5.1 4.8 4.5 4.2 4.0 3.7 3.5 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 1.9
7.9 7.5 7.0 6.6 6.2 5.8 5.4 5.1 4.8 4.5 4.2 3.9 3.7 3.5 3.2 3.0 2.8 2.7 2.5 2.3 2.2 2.1 1.9 1.8 1.7
8 6.5 6.0 5.7 5.3 5.0 4.7 4.4 4.1 3.9 3.6 3.4 3.2 3.0 2.8 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5
8.1 5.5 5.2 4.8 4.5 4.2 4.0 3.7 3.5 3.3 3.1 2.9 2.7 2.5 2.4 2.2 2.1 2.0 1.8 1.7 1.6 1.5 1.4 1.3 1.2
8.2 4.6 4.3 4.1 3.8 3.6 3.4 3.1 2.9 2.8 2.6 2.4 2.3 2.1 2.0 1.9 1.8 1.7 1.5 1.5 1.4 1.3 1.2 1.1 1.1
8.3 3.9 3.6 3.4 3.2 3.0 2.8 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9
8.4 3.2 3.0 2.8 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7
8.5 2.6 2.5 2.3 2.2 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6
8.6 2.1 2.0 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5 0.5
8.7 1.7 1.6 1.5 1.4 1.3 1.3 1.2 1.1 1.0 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.5 0.4 0.4
8.8 1.4 1.3 1.2 1.2 1.1 1.0 1.0 0.9 0.8 0.8 0.7 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3
8.9 1.1 1.1 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.6 0.5 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3
9 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 0.5 0.5 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.2

1 The freshwater chronic water quality criteria for total ammonia where fish early life stages are absent and​ freshwater mussels are absent were calculated using the following equation, which may also be used to calculate unlisted values:

​Freshwater chronic water quality criterion for ammonia (fish early life stages absent​ and freshwater mussels absent)= CCC=


Where MAX indicates the greater of the two values separated by a comma.

J. Saltwater and Estuarine Acute Criteria for Ammonia. Acute numeric toxic substance criteria for ammonia to protect marine and estuarine life are shown in Table 1. In estuarine and saltwaters, the concentration of total ammonia (in milligrams/liter) may not exceed the acute criterion listed in Table 1. Milligrams per liter total ammonia in saltwater (Table 1) may be converted to milligrams of ammonia nitrogen per liter (as used in §§H and I of this regulation) by multiplying the criteria values in Table 1 by 14/17 (or 0.82353) to result in total ammonia nitrogen.

Table 1 Acute Water Quality Criteria for Saltwater Aquatic Life (milligrams per liter total ammonia).

Temperature (°C)
0 5 10 15 20 25 30 35
pH Salinity = 10 parts per thousand
7.0 270 191 131 92 62 44 29 21
7.2 175 121 83 58 40 27 19 13
7.4 110 77 52 35 25 17 12 8.3
7.6 69 48 33 23 16 11 7.7 5.6
7.8 44 31 21 15 10 7.1 5.0 3.5
8.0 27 19 13 9.4 6.4 4.6 3.1 2.3
8.2 18 12 8.5 5.8 4.2 2.9 2.1 1.5
8.4 11 7.9 5.4 3.7 2.7 1.9 1.4 1.0
8.6 7.3 5.0 3.5 2.5 1.8 1.3 0.98 0.75
8.8 4.6 3.3 2.3 1.7 1.2 0.92 0.71 0.56
9.0 2.9 2.1 1.5 1.1 0.85 0.67 0.52 0.44
pH Salinity = 20 parts per thousand
7.0 291 200 137 96 64 44 31 21
7.2 183 125 87 60 42 29 20 14
7.4 116 79 54 37 27 18 12 8.7
7.6 73 50 35 23 17 11 7.9 5.6
7.8 46 31 23 15 11 7.5 5.2 3.5
8.0 29 20 14 9.8 6.7 4.8 3.3 2.3
8.2 19 13 8.9 6.2 4.4 3.1 2.1 1.6
8.4 12 8.1 5.6 4.0 2.9 2.0 1.5 1.1
8.6 7.5 5.2 3.7 2.7 1.9 1.4 1.0 0.77
8.8 4.8 3.3 2.5 1.7 1.3 0.94 0.73 0.56
9.0 3.1 2.3 1.6 1.2 0.87 0.69 0.54 0.44
pH Salinity = 30 parts per thousand
7.0 312 208 148 102 71 48 33 23
7.2 196 135 94 64 44 31 21 15
7.4 125 85 58 40 27 19 13 9.4
7.6 79 54 37 25 21 12 8.5 6.0
7.8 50 33 23 16 11 7.9 5.4 3.7
8.0 31 21 15 10 7.3 5.0 3.5 2.5
8.2 20 14 9.6 6.7 4.6 3.3 2.3 1.7
8.4 12.7 8.7 6.0 4.2 2.9 2.1 1.6 1.1
8.6 8.1 5.6 4.0 2.7 2.0 1.4 1.1 0.81
8.8 5.2 3.5 2.5 1.8 1.3 1.0 0.75 0.58
9.0 3.3 2.3 1.7 1.2 0.94 0.71 0.56 0.46

K. Saltwater and Estuarine Chronic Criteria for Ammonia.

(1) Chronic numeric toxic substance criteria for ammonia to protect marine and estuarine life are shown in Table 1.

(2) Averaging Period. The concentration of total ammonia (in milligrams/liter) expressed as a 30-day average may not exceed the chronic criterion listed in Table 1.

(3) Milligrams per liter total ammonia in saltwater (Table 1) may be converted to milligrams of ammonia nitrogen per liter (as used in §§H and I of this regulation) by multiplying the criteria values in Table 1 by 14/17 (or 0.82353) to result in total ammonia nitrogen.

Table 1 Chronic Water Quality Criteria for Saltwater Aquatic Life (milligrams/liter total ammonia).

Temperature (°C)
0 5 10 15 20 25 30 35
pH Salinity = 10 parts per thousand
7.0 41 29 20 14 9.4 6.6 4.4 3.1
7.2 26 18 12 8.7 5.9 4.1 2.8 2.0
7.4 17 12 7.8 5.3 3.7 2.6 1.8 1.2
7.6 10 7.2 5.0 3.4 2.4 1.7 1.2 0.84
7.8 6.6 4.7 3.1 2.2 1.5 1.1 0.75 0.53
8.0 4.1 2.9 2.0 1.40 0.97 0.69 0.47 0.34
8.2 2.7 1.8 1.3 0.87 0.62 0.44 0.31 0.23
8.4 1.7 1.2 0.81 0.56 0.41 0.29 0.21 0.16
8.6 1.1 0.75 0.53 0.37 0.27 0.20 0.15 0.11
8.8 0.69 0.50 0.34 0.25 0.18 0.14 0.11 0.08
9.0 0.44 0.31 0.23 0.17 0.13 0.10 0.08 0.07
pH Salinity = 20 parts per thousand
7.0 44 30 21 14 9.7 6.6 4.7 3.1
7.2 27 19 13 9.0 602 4.4 3.0 2.1
7.4 18 12 8.1 5.6 4.1 2.7 1.9 1.3
7.6 11 7.5 5.3 3.4 2.5 1.7 1.2 0.84
7.8 6.9 4.7 3.4 2.3 1.6 1.1 0.78 0.53
8.0 4.4 3.0 2.1 1.5 1.0 0.72 0.50 0.34
8.2 2.8 1.9 1.3 0.94 0.66 0.47 0.31 0.24
8.4 1.8 1.2 0.84 0.59 0.44 0.30 0.22 0.16
8.6 1.1 0.78 0.56 0.41 0.28 0.20 0.15 0.12
8.8 0.72 0.50 0.37 0.26 0.19 0.14 0.11 0.08
9.0 0.47 0.34 0.24 0.18 0.13 0.10 0.08 0.07
pH Salinity = 30 parts per thousand
7.0 47 31 22 15 11 7.2 5.0 3.4
7.2 29 20 14 9.7 6.6 4.7 3.1 2.2
7.4 19 13 8.7 5.9 4.1 2.9 2.0 1.4
7.6 12 8.1 5.6 3.7 3.1 1.8 1.3 0.90
7.8 7.5 5.0 3.4 2.4 1.7 1.2 0.81 0.56
8.0 4.7 3.1 2.2 1.6 1.1 0.75 0.53 0.37
8.2 3.0 2.1 1.4 1.0 0.69 0.50 0.34 0.25
8.4 1.9 1.3 0.90 0.62 0.44 0.31 0.23 0.17
8.6 1.2 0.84 0.59 0.41 0.30 0.22 0.16 0.12
8.8 0.78 0.53 0.37 0.27 0.20 0.15 0.11 0.09
9.​0 0.50 0.3​4 0.26 0.19 0.14 0.11 0.08 0.07​