26.08.02.03-02

.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 6 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—6 of §G. For the instream application of the acute and chronic criteria for the protection of aquatic life in Tables 1—6 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

0.18 d

1.4 a,d

0.010

Asbestos

1332214

7 million fibers/L

7 million fibers/L

Barium

7440393

1,000

2

Beryllium

4

0.004

Cadmium 1

7440439

1.8

0.72

33.13

7.9

5

0.005

Chlorine 2

7782505

19

11

13

7.5

Chromium
(total)

7440473

100

0.1

Chromium III 1

16065831

570

74

Chromium VI

18540299

16

11

1100

50

Copper 1

7440508

13

9

6.1

4.8

3.1

1,300 d

1.3 c

Cyanide

57125

22

5.2

1

1

140

140

0.2

Lead 1

7439921

65

2.5

210

8.1

0.015 c

Mercury

7439976

1.4

0.77

1.8

0.94

0.002

Methylmercury b

22967926

0.3 mg/kg in fish tissue

Nickel 1

7440020

470

52

74

8.2

610

4,600

Selenium

7782492

20

5

290

71

170

4,200

0.05

Silver 1

7440224

3.2

1.9

0.10

Thallium

7440280

0.24

0.47

0.002

Zinc 1

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 = e mA *LN(hardness)+bA *CF

Chronic Criteria = e mC *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

1.7 a

40 a

1,1,2-Trichloroethane

79005

5.9 a

160 a

0.005

1,2,4-Trichlorobenzene

120821

35 a

70 a

0.07

1,2,4,5-Tetrachlorobenzene

95943

0.03

0.03

1,2-Dichlorobenzene

95501

1000

3000

0.6

1,2-Dichloroethane

107062

99 a

6500 a

0.005

1,2-Dichloropropane

78875

5 a

150 a

0.005

1,2-Diphenylhydrazine

122667

0.3 a

2 a

1,2-Trans-Dichloroethylene

156605

100

4000

0.1

1,3-Dichlorobenzene

541731

320

960

1,3-Dichloropropene

542756

3.4 a

210 a

1,4-Dichlorobenzene

106467

300

900

0.075

2,4,5-Trichlorophenol

95954

300

600

2,4,6-Trichlorophenol

88062

14 a

24 a

2,4-Dichlorophenol

120832

77

290

2,4-Dimethylphenol

105679

100

3000

2,4-Dinitrotoluene

121142

1.1 a

34 a

2-Chloronapthalene

91587

800

1000

2-Chlorophenol

95578

81

150

2-Methyl-4,6-Dinitrophenol

534521

2

30

3,3'-Dichlorobenzidine

91941

0.49 a

1.5 a

3-Methyl-4-Chlorophenol

59507

500

2000

Acrolein

107028

3

3

6

9

Acrylonitrile

107131

0.61 a

70 a

Benzene

71432

22 a

510 a

0.005

Benzidine

92875

0.0014 a

0.11 a

Bis(2-Chloroethyl) Ether

111444

0.3 a

22 a

Bis2(Chloroisopropyl) Ether

108601

200

4000

Bis(Chloromethyl) Ether

542881

0.0015 a

0.17 a

Bromoform 1

75252

See
Trihalomethanes

1400 a

Carbon tetrachloride

56235

4 a

50 a

0.005

Chlorobenzene

108907

130

1600

0.1

Chlorodibromomethane 1

124481

8 a

210 a

Chloroform 1

67663

60

2000

Chlorophenoxy Herbicide (2,4-D)

94757

1300

12000

Chlorophenoxy Herbicide (2,4,5-TP)

93721

100

400

Dichlorobromomethane 1

75274

See
Trihalomethanes

170 a

Dinitrophenols

25550587

10

1000

Ethylbenzene

100414

530

2100

0.7

Hexachlorobenzene

118741

0.00079 a

0.00079 a

0.001

Hexachlorobutadiene

87683

4.4 a

180 a

Hexachlorocyclopenta-diene

77474

4

4

0.05

Hexachloroethane

67721

14 a

33 a

Hexachlorocyclohexane (HCH)-Technical

608731

0.066 a

0.1 a

Isophorone

78591

340 a

18000 a

Methoxychlor

72435

0.02

0.02

Methyl bromide

74839

100

10000

Methylene chloride

75092

200 a

10000 a

0.005

Nitrobenzene

98953

10

600

N-Nitrosodimethylamine

62759

0.0069 a

30 a

N-Nitrosodi-n-Propylamine

621647

0.05 a

5.1 a

N-Nitrosodiphenylamine

86306

33 a

60 a

Nonylphenol

84852153

28

6.6

7

1.7

Phenol

108952

4000

300000

Tetrachloroethylene

127184

100 a

290 a

0.005

Toluene

108883

1300

15000

1

Trichloroethylene (TCE)

79016

6 a

70 a

0.005

Trihalomethanes 1

80

0.08

Vinyl chloride

75014

0.22 a

16 a

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

0.012 a

0.013 a

Benzo(a)Pyrene

50328

0.0012 a

0.0013 a

0.0002

Benzo(b)Fluoranthene

205992

0.012 a

0.013 a

Benzo(k)Fluoranthene

207089

0.12 a

0.13 a

Chrysene

218019

0.038 a

0.18 a

Dibenzo(a,h)Anthracene

53703

0.0012 a

0.0013 a

Fluoranthene

206440

20

20

Fluorene

86737

50

70

Ideno(1,2,3-cd)Pyrene

193395

0.012 a

0.013 a

Pyrene

129000

20

30

Bis(2-Ethylhexyl) Phthalate

117817

3.2 a

3.7 a

0.006

Butylbenzyl Phthalate

85687

1 a

1 a

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

0.00000005 a

0.00000051 a

3 X 10 -8

4,4'-DDD

72548

0.0012 a

0.0012 a

4,4'-DDE

72559

0.0018 a

0.0018 a

4,4'-DDT

50293

1.1

0.001

0.13

0.001

0.0003 a

0.0003 a

Aldrin

309002

3

1.3

0.0000077 a

0.0000077 a

alpha-BHC

319846

0.036 a

0.039 a

alpha-Endosulfan

959988

0.22

0.056

0.034

0.0087

20

30

Atrazine

1912249

3

0.003

beta-BHC

319857

0.08 a

0.14 a

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

0.0031 a

0.0032 a

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

0.000012 a

0.000012 a

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

0.000059 a

0.000059 a

0.0004

Heptachlor Epoxide

1024573

0.52

0.0038

0.053

0.0036

0.00032 a

0.00032 a

0.0002

Polychlorinated Biphenyls PCBs

0.014

0.03

0.00064 a

0.00064 a

0.0005

Toxaphene

8001352

0.73

0.002

0.21

0.002

0.007 a

0.0071 a

0.003

Tributyltin (TBT)

0.46

0.072

0.42

0.0074

Pentachlorobenzene

608935

0.1

0.1

Pentachlorophenol (PCP) 1

87865

19

15

13

7.9

2.7 a

30 a

0.001

1 The freshwater aquatic life criteria for PCP are expressed as a function of pH. Refer to §D of this regulation.

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 ( 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

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 .

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 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) =

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 1/2 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

4.92

4.61

4.33

4.06

3.80

3.57

3.34

3.13

2.94

2.75

2.58

2.42

2.27

2.13

2.00

1.87

1.75

1.64

1.54

1.45

1.36

1.27

1.19

1.12

6.6

4.85

4.54

4.26

3.99

3.75

3.51

3.29

3.09

2.89

2.71

2.54

2.38

2.24

2.10

1.97

1.84

1.73

1.62

1.52

1.42

1.33

1.25

1.17

1.10

6.7

4.76

4.46

4.18

3.92

3.68

3.45

3.23

3.03

2.84

2.66

2.50

2.34

2.19

2.06

1.93

1.81

1.70

1.59

1.49

1.40

1.31

1.23

1.15

1.08

6.8

4.65

4.36

4.08

3.83

3.59

3.37

3.16

2.96

2.77

2.60

2.44

2.29

2.14

2.01

1.88

1.77

1.66

1.55

1.46

1.37

1.28

1.20

1.13

1.05

6.9

4.52

4.23

3.97

3.72

3.49

3.27

3.07

2.88

2.70

2.53

2.37

2.22

2.08

1.95

1.83

1.72

1.61

1.51

1.42

1.33

1.24

1.17

1.09

1.03

7

4.36

4.09

3.84

3.60

3.37

3.16

2.96

2.78

2.60

2.44

2.29

2.15

2.01

1.89

1.77

1.66

1.56

1.46

1.37

1.28

1.20

1.13

1.06

0.99

7.1

4.18

3.92

3.68

3.45

3.23

3.03

2.84

2.66

2.50

2.34

2.20

2.06

1.93

1.81

1.70

1.59

1.49

1.40

1.31

1.23

1.15

1.08

1.01

0.95

7.2

3.98

3.73

3.50

3.28

3.07

2.88

2.70

2.53

2.38

2.23

2.09

1.96

1.84

1.72

1.61

1.51

1.42

1.33

1.25

1.17

1.10

1.03

0.96

0.90

7.3

3.75

3.51

3.29

3.09

2.90

2.72

2.55

2.39

2.24

2.10

1.97

1.84

1.73

1.62

1.52

1.43

1.34

1.25

1.17

1.10

1.03

0.97

0.91

0.85

7.4

3.49

3.28

3.07

2.88

2.70

2.53

2.37

2.23

2.09

1.96

1.83

1.72

1.61

1.51

1.42

1.33

1.25

1.17

1.10

1.03

0.96

0.90

0.85

0.79

7.5

3.22

3.02

2.83

2.66

2.49

2.33

2.19

2.05

1.92

1.80

1.69

1.59

1.49

1.39

1.31

1.22

1.15

1.08

1.01

0.95

0.89

0.83

0.78

0.73

7.6

2.94

2.75

2.58

2.42

2.27

2.13

1.99

1.87

1.75

1.64

1.54

1.44

1.35

1.27

1.19

1.12

1.05

0.98

0.92

0.86

0.81

0.76

0.71

0.67

7.7

2.64

2.48

2.32

2.18

2.04

1.91

1.79

1.68

1.58

1.48

1.39

1.30

1.22

1.14

1.07

1.00

0.94

0.88

0.83

0.78

0.73

0.68

0.64

0.60

7.8

2.35

2.20

2.07

1.94

1.82

1.70

1.60

1.50

1.40

1.32

1.23

1.16

1.08

1.02

0.95

0.89

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.53

7.9

2.07

1.94

1.82

1.70

1.60

1.50

1.40

1.32

1.23

1.16

1.08

1.02

0.95

0.89

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.53

0.50

0.47

8

1.80

1.68

1.58

1.48

1.39

1.30

1.22

1.14

1.07

1.01

0.94

0.88

0.83

0.78

0.73

0.68

0.64

0.60

0.56

0.53

0.49

0.46

0.43

0.41

8.1

1.55

1.45

1.36

1.28

1.20

1.12

1.05

0.99

0.92

0.87

0.81

0.76

0.71

0.67

0.63

0.59

0.55

0.52

0.49

0.45

0.43

0.40

0.37

0.35

8.2

1.32

1.24

1.16

1.09

1.02

0.96

0.90

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.54

0.50

0.47

0.44

0.41

0.39

0.36

0.34

0.32

0.30

8.3

1.13

1.05

0.99

0.93

0.87

0.82

0.76

0.72

0.67

0.63

0.59

0.55

0.52

0.49

0.46

0.43

0.40

0.38

0.35

0.33

0.31

0.29

0.27

0.26

8.4

0.95

0.89

0.84

0.78

0.74

0.69

0.65

0.61

0.57

0.53

0.50

0.47

0.44

0.41

0.39

0.36

0.34

0.32

0.30

0.28

0.26

0.25

0.23

0.22

8.5

0.80

0.75

0.71

0.66

0.62

0.58

0.55

0.51

0.48

0.45

0.42

0.40

0.37

0.35

0.33

0.31

0.29

0.27

0.25

0.24

0.22

0.21

0.19

0.18

8.6

0.68

0.64

0.60

0.56

0.52

0.49

0.46

0.43

0.41

0.38

0.36

0.33

0.31

0.29

0.28

0.26

0.24

0.23

0.21

0.20

0.19

0.18

0.16

0.15

8.7

0.57

0.54

0.50

0.47

0.44

0.42

0.39

0.37

0.34

0.32

0.30

0.28

0.27

0.25

0.23

0.22

0.20

0.19

0.18

0.17

0.16

0.15

0.14

0.13

8.8

0.49

0.46

0.43

0.40

0.38

0.35

0.33

0.31

0.29

0.27

0.26

0.24

0.23

0.21

0.20

0.19

0.17

0.16

0.15

0.14

0.13

0.13

0.12

0.11

8.9

0.42

0.39

0.37

0.34

0.32

0.30

0.28

0.27

0.25

0.23

0.22

0.21

0.19

0.18

0.17

0.16

0.15

0.14

0.13

0.12

0.11

0.11

0.10

0.09

9

0.36

0.34

0.32

0.30

0.28

0.26

0.24

0.23

0.21

0.20

0.19

0.18

0.17

0.16

0.15

0.14

0.13

0.12

0.11

0.11

0.10

0.09

0.09

0.08

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 MAX indicates the greater 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

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

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.34

7.04

6.60

6.19

5.80

5.44

5.10

4.78

4.48

4.20

6.6

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

7.23

6.93

6.50

6.09

5.71

5.36

5.02

4.71

4.41

4.14

6.7

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

7.10

6.80

6.38

5.98

5.61

5.26

4.93

4.62

4.33

4.06

6.8

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.93

6.65

6.23

5.84

5.48

5.14

4.81

4.51

4.23

3.97

6.9

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.74

6.46