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7050.0222 SPECIFIC WATER QUALITY STANDARDS FOR CLASS 2 WATERS OF THE STATE; AQUATIC LIFE AND RECREATION.

Subpart 1.

General.

A.

The numeric and narrative water quality standards in this part prescribe the qualities or properties of the waters of the state that are necessary for the aquatic life and recreation designated public uses and benefits. If the standards in this part are exceeded in waters of the state that have the Class 2 designation, it is considered indicative of a polluted condition which is actually or potentially deleterious, harmful, detrimental, or injurious with respect to the designated uses.

B.

Standards for metals are expressed as total metal in this part, but must be converted to dissolved metal standards for application to surface waters. Conversion factors for converting total to dissolved metal standards are listed in subpart 9. The conversion factor for metals not listed in subpart 9 is one. The dissolved metal standard equals the total metal standard times the conversion factor. Water quality-based effluent limits for metals are expressed as total metal.

C.

The tables of standards in this part include the following abbreviations and acronyms:

* an asterisk following the FAV and MS values or double dashes (--) means subpart 7, item E, applies
(c) means the chemical is assumed to be a human carcinogen
°C means degrees Celsius
CS means chronic standard, defined in part 7050.0218, subpart 3
-- double dashes means there is no standard
°F means degrees Fahrenheit
FAV means final acute value, defined in part 7050.0218, subpart 3
HH in the "basis" column means the standard is human health-based
MS means maximum standard, defined in part 7050.0218, subpart 3
NA means not applicable
su means standard unit. It is the reporting unit for pH
TH means total hardness in milligrams per liter, which is the sum of the calcium and magnesium concentrations expressed as CaCO3
Tox in the "basis" column means the standard is toxicity-based

D.

Important synonyms or acronyms for some chemicals are listed in parentheses below the primary name.

Subp. 2.

Class 2A waters; aquatic life and recreation.

The quality of Class 2A surface waters shall be such as to permit the propagation and maintenance of a healthy community of cold water sport or commercial fish and associated aquatic life, and their habitats. These waters shall be suitable for aquatic recreation of all kinds, including bathing, for which the waters may be usable. This class of surface waters is also protected as a source of drinking water. Abbreviations, acronyms, and symbols are explained in subpart 1.

Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Acenaphthene μg/L 20 HH 56 112 Tox
Acetochlor μg/L 3.6 Tox 86 173 Tox
Acrylonitrile (c) μg/L 0.38 HH 1,140* 2,281* Tox
Alachlor (c) μg/L 3.8 HH 800* 1,600* Tox
Aluminum, total μg/L 87 Tox 748 1,496 Tox
Ammonia un-ionized as N μg/L 16 Tox -- -- NA

The percent un-ionized ammonia can be calculated for any temperature and pH by using the following equation taken from Emerson, K., R.C. Russo, R.E. Lund, and R.V. Thurston, Aqueous ammonia equilibrium calculations; effect of pH and temperature. Journal of the Fisheries Research Board of Canada 32: 2379-2383 (1975):

1
f = _ x 100
(pka - pH)
10 + 1
where: f = the percent of total ammonia in the un-ionized state
pka= 0.09 + (2730/T) (dissociation constant for ammonia)
T = temperature in degrees Kelvin (273.16° Kelvin = 0° Celsius)
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Anthracene μg/L 0.035 Tox 0.32 0.63 Tox
Antimony, total μg/L 5.5 HH 90 180 Tox
Arsenic, total μg/L 2.0 HH 360 720 Tox
Atrazine (c) μg/L 3.4 HH 323 645 Tox
Benzene (c) μg/L 5.1 HH 4,487* 8,974* Tox
Bromoform μg/L 33 HH 2,900 5,800 Tox
Cadmium, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.7852[ln(total hardness mg/L)]-3.490)

The MS in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-3.828)

The FAV in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-3.1349)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total cadmium standards for five hardness values:

TH in mg/L 50 100 200 300 400
_
Cadmium, total
CS μg/L 0.66 1.1 2.0 2.7 3.4
MS μg/L 1.8 3.9 8.6 14 19
FAV μg/L 3.6 7.8 17 27 37
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Carbon tetrachloride (c) μg/L 1.9 HH 1750* 3500* Tox
Chlordane (c) ng/L 0.073 HH 1200* 2400* Tox
Chloride mg/L 230 Tox 860 1720 Tox
Chlorine, total residual μg/L 11 Tox 19 38 Tox

Chlorine standard applies to conditions of continuous exposure, where continuous exposure refers to chlorinated effluents that are discharged for more than a total of two hours in any 24-hour period.

Chlorobenzene (Monochlorobenzene) μg/L 20 HH 423 846 Tox
Chloroform (c) μg/L 53 HH 1,392 2,784 Tox
Chlorpyrifos μg/L 0.041 Tox 0.083 0.17 Tox
Chromium +3, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+1.561)

The MS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+3.688)

The FAV in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+4.380)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total chromium +3 standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Chromium +3, total
CS μg/L 117 207 365 509 644
MS μg/L 984 1,737 3,064 4,270 5,405
FAV μg/L 1,966 3,469 6,120 8,530 10,797
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Chromium +6, total μg/L 11 Tox 16 32 Tox
Cobalt, total μg/L 2.8 HH 436 872 Tox
Color value Pt/Co 30 NA -- -- NA
Copper, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.620[ln(total hardness mg/L)]-0.570)

The MS in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-1.464)

The FAV in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-0.7703)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total copper standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Copper, total
CS μg/L 6.4 9.8 15 19 23
MS μg/L 9.2 18 34 50 65
FAV μg/L 18 35 68 100 131
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Cyanide, free μg/L 5.2 Tox 22 45 Tox
DDT (c) ng/L 0.11 HH 550* 1100* Tox
1,2-Dichloroethane (c) μg/L 3.5 HH 45,050* 90,100* Tox
Dieldrin (c) ng/L 0.0065 HH 1,300* 2,500* Tox
Di-2-ethylhexyl phthalate (c) μg/L 1.9 HH --* --* NA
Di-n-octyl phthalate μg/L 30 Tox 825 1,650 Tox
Endosulfan μg/L 0.0076 HH 0.084 0.17 Tox
Endrin μg/L 0.0039 HH 0.090 0.18 Tox
Escherichia (E.) coli See
below
See
below
HH See
below
See
below
NA

Not to exceed 126 organisms per 100 milliliters as a geometric mean of not less than five samples representative of conditions within any calendar month, nor shall more than ten percent of all samples taken during any calendar month individually exceed 1,260 organisms per 100 milliliters. The standard applies only between April 1 and October 31.

Ethylbenzene μg/L 68 Tox 1,859 3,717 Tox
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_

Eutrophication standards for Class 2A lakes and reservoirs.

Designated lake trout lakes in all ecoregions (lake trout lakes support natural populations of lake trout, Salvelinus namaycush):

Phosphorus, total μg/L 12 NA -- -- NA
Chlorophyll-a μg/L 3 NA -- -- NA
Secchi disk transparency meters No less
than 4.8
NA -- -- NA

Designated trout lakes in all ecoregions, except lake trout lakes:

Phosphorus, total μg/L 20 NA -- -- NA
Chlorophyll-a μg/L 6 NA -- -- NA
Secchi disk transparency meters No less
than 2.5
NA -- -- NA

Additional narrative eutrophication standards for Class 2A lakes and reservoirs are found under subpart 2a.

Eutrophication standards for Class 2A rivers and streams.

North River Nutrient Region:
Phosphorus, total μg/L less than or equal to 50
Chlorophyll-a (seston) μg/L less than or equal to 7
Diel dissolved oxygen flux mg/L less than or equal to 3.0
Biochemical oxygen demand (BOD5) mg/L less than or equal to 1.5
Central River Nutrient Region:
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 18
Diel dissolved oxygen flux mg/L less than or equal to 3.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 2.0
South River Nutrient Region:
Phosphorus, total μg/L less than or equal to 150
Chlorophyll-a (seston) μg/L less than or equal to 35
Diel dissolved oxygen flux mg/L less than or equal to 4.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 3.0

Additional narrative eutrophication standards for Class 2A rivers and streams are found under subpart 2b.

Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Fluoranthene μg/L 1.9 Tox 3.5 6.9 Tox
Heptachlor (c) ng/L 0.10 HH 260* 520* Tox
Heptachlor epoxide (c) ng/L 0.12 HH 270* 530* Tox
Hexachlorobenzene (c) ng/L 0.061 HH --* --* Tox
Lead, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-4.705)

The MS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-1.460)

The FAV in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-0.7643)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total lead standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Lead, total
CS μg/L 1.3 3.2 7.7 13 19
MS μg/L 34 82 197 331 477
FAV μg/L 68 164 396 663 956
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Lindane (c) (Hexachlorocyclohexane, gamma-) μg/L 0.0087 HH 1.0* 2.0* Tox
Mercury, total in water ng/L 6.9 HH 2,400* 4,900* Tox
Mercury, total
in edible fish
mg/kg
ppm
0.2 HH NA NA NA
Methylene chloride (c) Dichloromethane) μg/L 45 HH 13,875* 27,749* Tox
Metolachlor μg/L 23 Tox 271 543 Tox
Naphthalene μg/L 65 HH 409 818 Tox
Nickel, total μg/L equation Tox/HH equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS shall not exceed the human health-based standard of 297 μg/L. For waters with total hardness values less than 212 mg/L, the CS in μg/L is toxicity-based and shall not exceed: exp.(0.846[ln(total hardness mg/L)]+1.1645)

The MS in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+3.3612)

The FAV in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+4.0543)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total nickel standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Nickel, total
CS μg/L 88 158 283 297 297
MS μg/L 789 1,418 2,549 3,592 4,582
FAV μg/L 1,578 2,836 5,098 7,185 9,164
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Oil μg/L 500 NA 5,000 10,000 NA
Oxygen, dissolved mg/L See
below
NA -- -- NA

7.0 mg/L as a daily minimum. This dissolved oxygen standard requires compliance with the standard 50 percent of the days at which the flow of the receiving water is equal to the 7Q10.

Parathion μg/L 0.013 Tox 0.07 0.13 Tox
Pentachlorophenol μg/L 0.93 HH equation equation Tox

The MS and FAV vary with pH and are calculated using the following equations:

The MS in μg/L shall not exceed: exp.(1.005[pH]-4.830)

The FAV in μg/L shall not exceed: exp.(1.005[pH]-4.1373)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For pH values less than 6.0, 6.0 shall be used to calculate the standard and for pH values greater than 9.0, 9.0 shall be used to calculate the standard.

Example of pentachlorophenol standards for five pH values:

pH su 6.5 7.0 7.5 8.0 8.5
_
Pentachlorophenol
CS μg/L 0.93 0.93 0.93 0.93 0.93
MS μg/L 5.5 9.1 15 25 41
FAV μg/L 11 18 30 50 82
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
pH, minimum su 6.5 NA -- -- NA
pH, maximum su 8.5 NA -- -- NA
Phenanthrene μg/L 3.6 Tox 32 64 Tox
Phenol μg/L 123 Tox 2,214 4,428 Tox
Polychlorinated biphenyls, total (c) ng/L 0.014 HH 1,000* 2,000* Tox
Radioactive materials NA See
below
NA See
below
See
below
NA

Not to exceed the lowest concentrations permitted to be discharged to an uncontrolled environment as permitted by the appropriate authority having control over their use.

Selenium, total μg/L 5.0 Tox 20 40 Tox
Silver, total μg/L 0.12 Tox equation equation Tox

The MS and FAV vary with total hardness and are calculated using the following equations:

The MS in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-7.2156)

The FAV in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-6.520)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of silver standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Silver, total
CS μg/L 0.12 0.12 0.12 0.12 0.12
MS μg/L 1.0 2.0 6.7 13 22
FAV μg/L 1.2 4.1 13 27 44
Substance,
Characteristic,
or Pollutant
(Class 2A)
Units CS Basis
for CS
MS FAV Basis
for MS,
FAV
_
Temperature °C or
°F
No
material
increase
NA -- -- NA
1,1,2,2-Tetrachloroethane (c) μg/L 1.1 HH 1,127* 2,253* Tox
Tetrachloroethylene (c) μg/L 3.8 HH 428* 857* Tox
Thallium, total μg/L 0.28 HH 64 128 Tox
Toluene μg/L 253 Tox 1,352 2,703 Tox
Toxaphene (c) ng/L 0.31 HH 730* 1,500* Tox
1,1,1-Trichloroethane μg/L 329 Tox 2,957 5,913 Tox
1,1,2-Trichloroethylene (c) μg/L 25 HH 6,988* 13,976* Tox
2,4,6-Trichlorophenol μg/L 2.0 HH 102 203 Tox
Total suspended solids (TSS) mg/L 10 NA -- -- NA
TSS standards for Class 2A may be exceeded for no more than ten percent of the time. This standard applies April 1 through September 30
Vinyl chloride (c) μg/L 0.17 HH --* --* NA
Xylene, total m,p,o μg/L 166 Tox 1,407 2,814 Tox
Zinc, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.7615)

The MS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.8604)

The FAV in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+1.5536

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of zinc standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Zinc, total
CS μg/L 59 106 191 269 343
MS μg/L 65 117 211 297 379
FAV μg/L 130 234 421 594 758

Subp. 2a.

Narrative eutrophication standards for lakes and reservoirs.

A.

Eutrophication standards for lakes and reservoirs are compared to summer-average data. Exceedance of the total phosphorus and either the chlorophyll-a or Secchi disk transparency standard is required to indicate a polluted condition.

B.

It is the policy of the agency to protect all lakes and reservoirs from the undesirable effects of cultural eutrophication. Lakes and reservoirs with a baseline quality better than the numeric eutrophication standards in subpart 2 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources, and the protection of lake or reservoir resources, including, but not limited to:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

C.

Lakes and reservoirs with a baseline quality that is poorer than the numeric eutrophication standards in subpart 2 must be considered to be in compliance with the standards if the baseline quality is the result of natural causes. The commissioner shall determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

D.

When applied to reservoirs, the eutrophication standards in this subpart and subpart 2 may be modified on a site-specific basis to account for characteristics unique to reservoirs that can affect trophic status, such as water temperature, variations in hydraulic residence time, watershed size, and the fact that reservoirs may receive drainage from more than one ecoregion. Information supporting a site-specific standard can be provided by the commissioner or by any person outside the agency. The commissioner shall evaluate all data in support of a modified standard and determine whether a change in the standard for a specific reservoir is justified. Any total phosphorus effluent limit determined to be necessary based on a modified standard shall only be required after the discharger has been given notice of the specific proposed effluent limits and an opportunity to request a hearing as provided in part 7000.1800.

E.

Eutrophication standards applicable to lakes and reservoirs that lie on the border between two ecoregions or that are in the Red River Valley (also referred to as Lake Agassiz Plains), Northern Minnesota Wetlands, or Driftless Area Ecoregion must be applied on a case-by-case basis. The commissioner shall use the standards applicable to adjacent ecoregions as a guide.

Subp. 2b.

Narrative eutrophication standards for rivers and streams.

A.

Eutrophication standards for rivers and streams are compared to summer-average data or as specified in subpart 2. Exceedance of the total phosphorus levels and chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels is required to indicate a polluted condition.

B.

Rivers and streams that exceed the phosphorus levels but do not exceed the chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels meet the eutrophication standard.

C.

For chlorophyll-a (periphyton), the standard is exceeded if concentrations exceed 150 mg/m2 more than one year in ten.

D.

It is the policy of the agency to protect all rivers and streams from the undesirable effects of cultural eutrophication. Rivers and streams with a baseline quality better than the numeric eutrophication standards in subpart 3 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources, including:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable, in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

E.

Rivers and streams with a baseline quality that does not meet the numeric eutrophication standards in part 7050.0150, subpart 5b, are in compliance with the standards if the baseline quality is the result of natural causes. The commissioner must determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

Subp. 3.

Class 2Bd waters.

The quality of Class 2Bd surface waters shall be such as to permit the propagation and maintenance of a healthy community of cool or warm water sport or commercial fish and associated aquatic life and their habitats. These waters shall be suitable for aquatic recreation of all kinds, including bathing, for which the waters may be usable. This class of surface waters is also protected as a source of drinking water. The applicable standards are given below. Abbreviations, acronyms, and symbols are explained in subpart 1.

Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Acenaphthene μg/L 20 HH 56 112 Tox
Acetochlor μg/L 3.6 Tox 86 173 Tox
Acrylonitrile (c) μg/L 0.38 HH 1,140* 2,281* Tox
Alachlor (c) μg/L 4.2 HH 800* 1,600* Tox
Aluminum, total μg/L 125 Tox 1,072 2,145 Tox
Ammonia un-ionized as N μg/L 40 Tox -- -- NA

The percent un-ionized ammonia can be calculated for any temperature and pH by using the following equation taken from Emerson, K., R.C. Russo, R.E. Lund, and R.V. Thurston, Aqueous ammonia equilibrium calculations; effect of pH and temperature. Journal of the Fisheries Research Board of Canada 32: 2379-2383 (1975):

f = 1/(10(pka-pH) + 1) x 100

where: f = the percent of total ammonia in the un-ionized state
pka = 0.09 + (2730/T) (dissociation constant for ammonia)
T = temperature in degrees Kelvin (273.16° Kelvin = 0° Celsius)
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Anthracene μg/L 0.035 Tox 0.32 0.63 Tox
Antimony, total μg/L 5.5 HH 90 180 Tox
Arsenic, total μg/L 2.0 HH 360 720 Tox
Atrazine (c) μg/L 3.4 HH 323 645 Tox
Benzene (c) μg/L 6.0 HH 4,487* 8,974* Tox
Bromoform μg/L 41 HH 2,900 5,800 Tox
Cadmium, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.7852[ln(total hardness mg/L)]-3.490)

The MS in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-1.685)

The FAV in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-0.9919)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total cadmium standards for five hardness values:

TH in mg/L 50 100 200 300 400
_
Cadmium, total
CS μg/L 0.66 1.1 2.0 2.7 3.4
MS μg/L 15 33 73 116 160
FAV μg/L 31 67 146 231 319
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Carbon tetrachloride (c) μg/L 1.9 HH 1,750* 3,500* Tox
Chlordane (c) ng/L 0.29 HH 1,200* 2,400* Tox
Chloride mg/L 230 Tox 860 1,720 Tox
Chlorine, total residual μg/L 11 Tox 19 38 Tox

Chlorine standard applies to conditions of continuous exposure, where continuous exposure refers to chlorinated effluents that are discharged for more than a total of two hours in any 24-hour period.

Chlorobenzene (Monochlorobenzene) μg/L 20 HH 423 846 Tox
Chloroform (c) μg/L 53 HH 1,392 2,784 Tox
Chlorpyrifos μg/L 0.041 Tox 0.083 0.17 Tox
Chromium +3, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+1.561)

The MS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+3.688)

The FAV in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+4.380)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total chromium +3 standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Chromium +3, total
CS μg/L 117 207 365 509 644
MS μg/L 984 1,737 3,064 4,270 5,405
FAV μg/L 1,966 3,469 6,120 8,530 10,797
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Chromium +6, total μg/L 11 Tox 16 32 Tox
Cobalt, total μg/L 2.8 HH 436 872 Tox
Copper, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.620[ln(total hardness mg/L)]-0.570)

The MS in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-1.464)

The FAV in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-0.7703)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total copper standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Copper, total
CS μg/L 6.4 9.8 15 19 23
MS μg/L 9.2 18 34 50 65
FAV μg/L 18 35 68 100 131
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Cyanide, free μg/L 5.2 Tox 22 45 Tox
DDT (c) ng/L 1.7 HH 550* 1,100* Tox
1,2-Dichloroethane (c) μg/L 3.8 HH 45,050* 90,100* Tox
Dieldrin (c) ng/L 0.026 HH 1,300* 2,500* Tox
Di-2-ethylhexyl phthalate (c) μg/L 1.9 HH --* --* NA
Di-n-octyl phthalate μg/L 30 Tox 825 1,650 Tox
Endosulfan μg/L 0.029 HH 0.28 0.56 Tox
Endrin μg/L 0.016 HH 0.090 0.18 Tox
Escherichia (E.) coli See
below
See
below
HH See
below
See
below
NA

Not to exceed 126 organisms per 100 milliliters as a geometric mean of not less than five samples representative of conditions within any calendar month, nor shall more than ten percent of all samples taken during any calendar month individually exceed 1,260 organisms per 100 milliliters. The standard applies only between April 1 and October 31.

Ethylbenzene μg/L 68 Tox 1,859 3,717 Tox
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_

Eutrophication standards for Class 2Bd lakes, shallow lakes, and reservoirs.

Lakes, Shallow Lakes, and Reservoirs in Northern Lakes and Forest Ecoregion

Phosphorus, total μg/L 30 NA -- -- NA
Chlorophyll-a μg/L 9 NA -- -- NA
Secchi disk transparency meters Not less
than 2.0
NA -- -- NA

Lakes and Reservoirs in North Central Hardwood Forest Ecoregion

Phosphorus, total μg/L 40 NA -- -- NA
Chlorophyll-a μg/L 14 NA -- -- NA
Secchi disk transparency meters Not less
than 1.4
NA -- -- NA

Lakes and Reservoirs in Western Corn Belt Plains and Northern Glaciated Plains Ecoregions

Phosphorus, total μg/L 65 NA -- -- NA
Chlorophyll-a μg/L 22 NA -- -- NA
Secchi disk transparency meters Not less
than 0.9
NA -- -- NA

Shallow Lakes in North Central Hardwood Forest Ecoregion

Phosphorus, total μg/L 60 NA -- -- NA
Chlorophyll-a μg/L 20 NA -- -- NA
Secchi disk transparency meters Not less
than 1.0
NA -- -- NA

Shallow Lakes in Western Corn Belt Plains and Northern Glaciated Plains Ecoregions

Phosphorus, total μg/L 90 NA -- -- NA
Chlorophyll-a μg/L 30 NA -- -- NA
Secchi disk transparency meters Not less
than 0.7
NA -- -- NA

Additional narrative eutrophication standards for Class 2Bd lakes, shallow lakes, and reservoirs are found under subpart 3a.

Eutrophication standards for Class 2Bd rivers and streams.

North River Nutrient Region
Phosphorus, total μg/L less than or equal to 50
Chlorophyll-a (seston) μg/L less than or equal to 7
Diel dissolved oxygen flux mg/L less than or equal to 3.0
Biochemical oxygen demand (BOD5) mg/L less than or equal to 1.5
Central River Nutrient Region
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 18
Diel dissolved oxygen flux mg/L less than or equal to 3.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 2.0
South River Nutrient Region
Phosphorus, total μg/L less than or equal to 150
Chlorophyll-a (seston) μg/L less than or equal to 35
Diel dissolved oxygen flux mg/L less than or equal to 4.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 3.0

Additional narrative eutrophication standards for Class 2Bd rivers and streams are found under subpart 3b.

Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Fluoranthene μg/L 1.9 Tox 3.5 6.9 Tox
Heptachlor (c) ng/L 0.39 HH 260* 520* Tox
Heptachlor epoxide (c) ng/L 0.48 HH 270* 530* Tox
Hexachlorobenzene (c) ng/L 0.24 HH --* --* Tox
Lead, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-4.705)

The MS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-1.460)

The FAV in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-0.7643)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total lead standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Lead, total
CS μg/L 1.3 3.2 7.7 13 19
MS μg/L 34 82 197 331 477
FAV μg/L 68 164 396 663 956
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Lindane (c) (Hexachlorocyclohexane, gamma-) μg/L 0.032 HH 4.4* 8.8* Tox
Mercury, total in water ng/L 6.9 HH 2,400* 4,900* Tox
Mercury, total
in edible fish tissue
mg/kg
ppm
0.2 HH NA NA NA
Methylene chloride (c)
(Dichloromethane)
μg/L 46 HH 13,875* 27,749* Tox
Metolachlor μg/L 23 Tox 271 543 Tox
Naphthalene μg/L 81 Tox 409 818 Tox
Nickel, total μg/L equation Tox/HH equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS shall not exceed the human health-based standard of 297 μg/L. For waters with total hardness values less than 212 mg/L, the CS in μg/L is toxicity-based and shall not exceed: exp.(0.846[ln(total hardness mg/L)]+1.1645)

The MS in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+3.3612)

The FAV in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+4.0543)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total nickel standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Nickel, total
CS μg/L 88 158 283 297 297
MS μg/L 789 1,418 2,549 3,592 4,582
FAV μg/L 1,578 2,836 5,098 7,185 9,164
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Oil μg/L 500 NA 5,000 10,000 NA
Oxygen, dissolved mg/L See
below
NA -- -- NA

5.0 mg/L as a daily minimum. This dissolved oxygen standard may be modified on a site-specific basis according to part 7050.0220, subpart 7, except that no site-specific standard shall be less than 5 mg/L as a daily average and 4 mg/L as a daily minimum. Compliance with this standard is required 50 percent of the days at which the flow of the receiving water is equal to the 7Q10.

Parathion μg/L 0.013 Tox 0.07 0.13 Tox
Pentachlorophenol μg/L 1.9 HH equation equation Tox

The MS and FAV vary with pH and are calculated using the following equations:

The MS in μg/L shall not exceed: exp.(1.005[pH]-4.830)

The FAV in μg/L shall not exceed: exp.(1.005[pH]-4.1373)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For pH values less than 6.0, 6.0 shall be used to calculate the standard and for pH values greater than 9.0, 9.0 shall be used to calculate the standard.

Example of pentachlorophenol standards for five pH values:

pH su 6.5 7.0 7.5 8.0 8.5
_
Pentachlorophenol
CS μg/L 1.9 1.9 1.9 1.9 1.9
MS μg/L 5.5 9.1 15 25 41
FAV μg/L 11 18 30 50 82
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
pH, minimum su 6.5 NA -- -- NA
pH, maximum su 9.0 NA -- -- NA
Phenanthrene μg/L 3.6 Tox 32 64 Tox
Phenol μg/L 123 Tox 2,214 4,428 Tox
Polychlorinated biphenyls, total (c) ng/L 0.029 HH 1,000* 2,000* Tox
Radioactive materials NA See
below
NA See
below
See
below
NA

Not to exceed the lowest concentrations permitted to be discharged to an uncontrolled environment as permitted by the appropriate authority having control over their use.

Selenium, total μg/L 5.0 Tox 20 40 Tox
Silver, total μg/L 1.0 Tox equation equation Tox

The MS and FAV vary with total hardness and are calculated using the following equations:

The MS in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-7.2156)

The FAV in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-6.520)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total silver standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Silver, total
CS μg/L 1.0 1.0 1.0 1.0 1.0
MS μg/L 1.0 2.0 6.7 13 22
FAV μg/L 1.2 4.1 13 27 44
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Temperature °F See
below
NA -- -- NA

5°F above natural in streams and 3°F above natural in lakes, based on monthly average of the maximum daily temperatures, except in no case shall it exceed the daily average temperature of 86°F.

1,1,2,2-Tetrachloroethane (c) μg/L 1.5 HH 1,127* 2,253* Tox
Tetrachloroethylene (c) μg/L 3.8 HH 428* 857* Tox
Thallium, total μg/L 0.28 HH 64 128 Tox
Toluene μg/L 253 Tox 1,352 2,703 Tox
Toxaphene (c) ng/L 1.3 HH 730* 1,500* Tox
1,1,1-Trichloroethane μg/L 329 Tox 2,957 5,913 Tox
1,1,2-Trichloroethylene (c) μg/L 25 HH 6,988* 13,976* Tox
2,4,6-Trichlorophenol μg/L 2.0 HH 102 203 Tox
Total suspended solids (TSS)
North River Nutrient Region mg/L 15 NA - - NA
Central River Nutrient Region mg/L 30 NA - - NA
South River Nutrient Region mg/L 65 NA - - NA
Red River mainstem - headwaters to border mg/L 100 NA - - NA
TSS standards for the Class 2Bd North, Central, and South River Nutrient Regions and the Red River mainstem may be exceeded for no more than ten percent of the time. This standard applies April 1 through September 30
Total suspended solids (TSS), summer average
Lower Mississippi River mainstem - Pools 2 through 4 mg/L 32 NA - - NA
Lower Mississippi River mainstem below Lake Pepin mg/L 30 NA - - NA
TSS standards for the Class 2Bd Lower Mississippi River may be exceeded for no more than 50 percent of the time. This standard applies June 1 through September 30
Substance,
Characteristic,
or Pollutant
(Class 2Bd)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Vinyl chloride (c) μg/L 0.18 HH --* --* NA
Xylene, total m,p,o μg/L 166 Tox 1,407 2,814 Tox
Zinc, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.7615)

The MS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.8604)

The FAV in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+1.5536)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total zinc standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Zinc, total
CS μg/L 59 106 191 269 343
MS μg/L 65 117 211 297 379
FAV μg/L 130 234 421 594 758

Subp. 3a.

Narrative eutrophication standards for Class 2Bd lakes, shallow lakes, and reservoirs.

A.

Eutrophication standards applicable to lakes, shallow lakes, and reservoirs that lie on the border between two ecoregions or that are in the Red River Valley (also referred to as Lake Agassiz Plains), Northern Minnesota Wetlands, or Driftless Area Ecoregion must be applied on a case-by-case basis. The commissioner shall use the standards applicable to adjacent ecoregions as a guide.

B.

Eutrophication standards are compared to summer-average data. Exceedance of the total phosphorus and either the chlorophyll-a or Secchi disk transparency standard is required to indicate a polluted condition.

C.

It is the policy of the agency to protect all lakes, shallow lakes, and reservoirs from the undesirable effects of cultural eutrophication. Lakes, shallow lakes, and reservoirs with a baseline quality better than the numeric eutrophication standards in subpart 3 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources, and the protection of lake, shallow lake, and reservoir resources, including, but not limited to:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

D.

Lakes, shallow lakes, and reservoirs with a baseline quality that is poorer than the numeric eutrophication standards in subpart 3 must be considered to be in compliance with the standards if the baseline quality is the result of natural causes. The commissioner shall determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

E.

When applied to reservoirs, the eutrophication standards in this subpart and subpart 3 may be modified on a site-specific basis to account for characteristics of reservoirs that can affect trophic status, such as water temperature, variations in hydraulic residence time, watershed size, and the fact that reservoirs may receive drainage from more than one ecoregion. Information supporting a site-specific standard can be provided by the commissioner or by any person outside the agency. The commissioner shall evaluate all data in support of a modified standard and determine whether a change in the standard for a specific reservoir is justified. Any total phosphorus effluent limit determined to be necessary based on a modified standard shall only be required after the discharger has been given notice of the specific proposed effluent limits and an opportunity to request a hearing as provided in part 7000.1800.

Subp. 3b.

Narrative eutrophication standards for rivers, streams, and navigational pools.

A.

Eutrophication standards for rivers, streams, and navigational pools are compared to summer-average data or as specified in subpart 3. Exceedance of the total phosphorus levels and chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels is required to indicate a polluted condition.

B.

Rivers, streams, and navigational pools that exceed the phosphorus levels but do not exceed the chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels meet the eutrophication standard.

C.

A polluted condition also exists when the chlorophyll-a (periphyton) concentration exceeds 150 mg/m2 more than one year in ten.

D.

It is the policy of the agency to protect all rivers, streams, and navigational pools from the undesirable effects of cultural eutrophication. Rivers, streams, and navigational pools with a baseline quality better than the numeric eutrophication standards in subpart 3 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources including:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable, in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

E.

Rivers, streams, and navigational pools with a baseline quality that does not meet the numeric eutrophication standards in part 7050.0150, subpart 5b, are in compliance with the standards if the baseline quality is the result of natural causes. The commissioner must determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

Subp. 4.

Class 2B waters.

The quality of Class 2B surface waters shall be such as to permit the propagation and maintenance of a healthy community of cool or warm water sport or commercial fish and associated aquatic life, and their habitats. These waters shall be suitable for aquatic recreation of all kinds, including bathing, for which the waters may be usable. This class of surface water is not protected as a source of drinking water. The applicable standards are given below. Abbreviations, acronyms, and symbols are explained in subpart 1.

Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Acenaphthene μg/l 20 HH 56 112 Tox
Acetochlor μg/L 3.6 Tox 86 173 Tox
Acrylonitrile (c) μg/l 0.89 HH 1,140* 2,281* Tox
Alachlor (c) μg/L 59 Tox 800 1,600 Tox
Aluminum, total μg/L 125 Tox 1,072 2,145 Tox
Ammonia un-ionized as N μg/L 40 Tox -- -- NA

The percent un-ionized ammonia can be calculated for any temperature and pH by using the following equation taken from Emerson, K., R.C. Russo, R.E. Lund, and R.V. Thurston, Aqueous ammonia equilibrium calculations; effect of pH and temperature. Journal of the Fisheries Research Board of Canada 32: 2379-2383 (1975):

f = 1/(10(pka-pH) + 1) x 100

where: f = the percent of total ammonia in the un-ionized state
pka = 0.09 + (2730/T) (dissociation constant for ammonia)
T = temperature in degrees Kelvin (273.16° Kelvin = 0° Celsius)
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Anthracene μg/L 0.035 Tox 0.32 0.63 Tox
Antimony, total μg/L 31 Tox 90 180 Tox
Arsenic, total μg/L 53 HH 360 720 Tox
Atrazine (c) μg/L 10 Tox 323 645 Tox
Benzene (c) μg/L 98 HH 4,487 8,974 Tox
Bromoform μg/L 466 HH 2,900 5,800 Tox
Cadmium, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.7852[ln(total hardness mg/L)]-3.490)

The MS in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-1.685)

The FAV in μg/L shall not exceed: exp.(1.128[ln(total hardness mg/L)]-0.9919)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total cadmium standards for five hardness values:

TH in mg/L 50 100 200 300 400
_
Cadmium, total
CS μg/L 0.66 1.1 2.0 2.7 3.4
MS μg/L 15 33 73 116 160
FAV μg/L 31 67 146 231 319
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Carbon tetrachloride (c) μg/L 5.9 HH 1,750* 3,500* Tox
Chlordane (c) ng/L 0.29 HH 1,200* 2,400* Tox
Chloride mg/L 230 Tox 860 1,720 Tox
Chlorine, total residual μg/L 11 Tox 19 38 Tox

Chlorine standard applies to conditions of continuous exposure, where continuous exposure refers to chlorinated effluents that are discharged for more than a total of two hours in any 24-hour period.

Chlorobenzene (Monochlorobenzene) μg/L 20 HH 423 846 Tox
Chloroform (c) μg/L 155 Tox 1,392 2,784 Tox
Chlorpyrifos μg/L 0.041 Tox 0.083 0.17 Tox
Chromium +3, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations

The CS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+1.561)

The MS in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+3.688)

The FAV in μg/L shall not exceed: exp.(0.819[ln(total hardness mg/L)]+4.380)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total chromium +3 standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Chromium +3, total
CS μg/L 117 207 365 509 644
MS μg/L 984 1,737 3,064 4,270 5,405
FAV μg/L 1,966 3,469 6,120 8,530 10,797
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Chromium +6, total μg/L 11 Tox 16 32 Tox
Cobalt, total μg/L 5.0 Tox 436 872 Tox
Copper, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.6200[ln(total hardness mg/L)]-0.570)

The MS in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-1.464)

The FAV in μg/L shall not exceed: exp.(0.9422[ln(total hardness mg/L)]-0.7703)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total copper standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Copper, total
CS μg/L 6.4 9.8 15 19 23
MS μg/L 9.2 18 34 50 65
FAV μg/L 18 35 68 100 131
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Cyanide, free μg/L 5.2 Tox 22 45 Tox
DDT (c) ng/L 1.7 HH 550* 1,100* Tox
1,2-Dichloroethane (c) μg/L 190 HH 45,050* 90,100* Tox
Dieldrin (c) ng/L 0.026 HH 1,300* 2,500* Tox
Di-2-ethylhexyl phthalate (c) μg/L 2.1 HH --* --* NA
Di-n-octyl phthalate μg/L 30 Tox 825 1,650 Tox
Endosulfan μg/L 0.031 HH 0.28 0.56 Tox
Endrin μg/L 0.016 HH 0.090 0.18 Tox
Escherichia (E.) coli See
below
See
below
HH See
below
See
below
NA

Not to exceed 126 organisms per 100 milliliters as a geometric mean of not less than five samples representative of conditions within any calendar month, nor shall more than ten percent of all samples taken during any calendar month individually exceed 1,260 organisms per 100 milliliters. The standard applies only between April 1 and October 31.

Ethylbenzene μg/L 68 Tox 1,859 3,717 Tox
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_

Eutrophication standards for Class 2B lakes, shallow lakes, and reservoirs.

Lakes, Shallow Lakes, and Reservoirs in Northern Lakes and Forest Ecoregions

Phosphorus, total μg/L 30 NA -- -- NA
Chlorophyll-a μg/L 9 NA -- -- NA
Secchi disk transparency meters Not less
than 2.0
NA -- -- NA

Lakes and Reservoirs in North Central Hardwood Forest Ecoregion

Phosphorus, total μg/L 40 NA -- -- NA
Chlorophyll-a μg/L 14 NA -- -- NA
Secchi disk transparency meters Not less
than 1.4
NA -- -- NA

Lakes and Reservoirs in Western Corn Belt Plains and Northern Glaciated Plains Ecoregions

Phosphorus, total μg/L 65 NA -- -- NA
Chlorophyll-a μg/L 22 NA -- -- NA
Secchi disk transparency meters Not less
than 0.9
NA -- -- NA

Shallow Lakes in North Central Hardwood Forest Ecoregion

Phosphorus, total μg/L 60 NA -- -- NA
Chlorophyll-a μg/L 20 NA -- -- NA
Secchi disk transparency meters Not less
than 1.0
NA -- -- NA

Shallow Lakes in Western Corn Belt Plains and Northern Glaciated Plains Ecoregions

Phosphorus, total μg/L 90 NA -- -- NA
Chlorophyll-a μg/L 30 NA -- -- NA
Secchi disk transparency meters Not less
than 0.7
NA -- -- NA

Additional narrative eutrophication standards for Class 2B lakes, shallow lakes, and reservoirs are found in subpart 4a.

Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_

Eutrophication standards for Class 2B rivers and streams.

North River Nutrient Region
Phosphorus, total μg/L less than or equal to 50
Chlorophyll-a (seston) μg/L less than or equal to 7
Diel dissolved oxygen flux mg/L less than or equal to 3.0
Biochemical oxygen demand (BOD5) mg/L less than or equal to 1.5
Central River Nutrient Region
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 18
Diel dissolved oxygen flux mg/L less than or equal to 3.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 2.0
South River Nutrient Region
Phosphorus, total μg/L less than or equal to 150
Chlorophyll-a (seston) μg/L less than or equal to 40
Diel dissolved oxygen flux mg/L less than or equal to 5.0
Biochemical oxygen demand (BOD5) mg/L less than or equal to 3.5

Site-specific standards for specified river reaches or other waters are:

Mississippi River Navigational Pool 1 (river miles 854.1 to 847.7 reach from Fridley to Ford Dam in St. Paul)
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 35
Mississippi River Navigational Pool 2 (river miles 847.7 to 815.2 reach from Ford Dam to Hastings Dam)
Phosphorus, total μg/L less than or equal to 125
Chlorophyll-a (seston) μg/L less than or equal to 35
Mississippi River Navigational Pool 3 (river miles 815.2 to 796.9 reach from Hastings Dam to Red Wing Dam)
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 35
Mississippi River Navigational Pool 4 (river miles 796.9 to 752.8 reach from Red Wing Dam to Alma Dam). Lake Pepin occupies majority of Pool 4 and Lake Pepin site-specific standards are used for this pool.
Mississippi River Navigational Pools 5 to 8 (river miles 752.8 to 679.1 Alma Dam to Genoa Dam)
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 35
Lake Pepin
Phosphorus, total μg/L less than or equal to 100
Chlorophyll-a (seston) μg/L less than or equal to 28
Crow Wing River from confluence of Long Prairie River to the mouth of the Crow Wing River at the Mississippi River
Phosphorus, total μg/L less than or equal to 75
Chlorophyll-a (seston) μg/L less than or equal to 13
Diel dissolved oxygen flux mg/L less than or equal to 3.5
Biochemical oxygen demand (BOD5) mg/L less than or equal to 1.7
Crow River from the confluence of the North Fork of the Crow River and South Fork of the Crow River to the mouth of the Crow River at the Mississippi River
Phosphorus, total μg/L less than or equal to 125
Chlorophyll-a (seston) μg/L less than or equal to 27
Diel dissolved oxygen flux mg/L less than or equal to 4.0
Biochemical oxygen demand (BOD5) mg/L less than or equal to 2.5

Additional narrative eutrophication standards for Class 2B rivers and streams are found in subpart 4b.

Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Fluoranthene μg/L 1.9 Tox 3.5 6.9 Tox
Heptachlor (c) ng/L 0.39 HH 260* 520* Tox
Heptachlor epoxide (c) ng/L 0.48 HH 270* 530* Tox
Hexachlorobenzene (c) ng/L 0.24 HH --* --* Tox
Lead, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-4.705)

The MS in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-1.460)

The FAV in μg/L shall not exceed: exp.(1.273[ln(total hardness mg/L)]-0.7643)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total lead standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Lead, total
CS μg/L 1.3 3.2 7.7 13 19
MS μg/L 34 82 197 331 477
FAV μg/L 68 164 396 663 956
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Lindane (c) (Hexachlorocyclobenzene, gamma-) μg/L 0.036 HH 4.4* 8.8* Tox
Mercury, total in water ng/L 6.9 HH 2,400* 4,900* Tox
Mercury, total
in edible fish tissue
mg/kg
ppm
0.2 HH NA NA NA
Methylene chloride (c)
(Dichloromethane)
μg/L 1,940 HH 13,875 27,749 Tox
Metolachlor μg/L 23 Tox 271 543 Tox
Naphthalene μg/L 81 Tox 409 818 Tox
Nickel, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+1.1645)

The MS in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/L)]+3.3612)

The FAV in μg/L shall not exceed: exp.(0.846[ln(total hardness mg/l)]+4.0543)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total nickel standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Nickel, total
CS μg/L 88 158 283 399 509
MS μg/L 789 1,418 2,549 3,592 4,582
FAV μg/L 1,578 2,836 5,098 7,185 9,164
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Oil μg/l 500 NA 5,000 10,000 NA
Oxygen, dissolved mg/L See
below
NA -- -- NA

5.0 mg/L as a daily minimum. This dissolved oxygen standard may be modified on a site-specific basis according to part 7050.0220, subpart 7, except that no site-specific standard shall be less than 5 mg/L as a daily average and 4 mg/L as a daily minimum. Compliance with this standard is required 50 percent of the days at which the flow of the receiving water is equal to the 7Q10. This standard applies to all Class 2B waters except for those portions of the Mississippi River from the outlet of the Metro Wastewater Treatment Works in Saint Paul (River Mile 835) to Lock and Dam No. 2 at Hastings (River Mile 815). For this reach of the Mississippi River, the standard is not less than 5 mg/L as a daily average from April 1 through November 30, and not less than 4 mg/L at other times.

Parathion μg/L 0.013 Tox 0.07 0.13 Tox
Pentachlorophenol μg/L equation Tox/HH equation equation Tox

The CS, MS, and FAV vary with pH and are calculated using the following equations:

For waters with pH values greater than 6.95, the CS shall not exceed the human health-based standard of 5.5 μg/L.

For waters with pH values less than 6.96, the CS in μg/L shall not exceed the toxicity-based standard of exp.(1.005[pH]-5.290)

The MS in μg/L shall not exceed: exp.(1.005[pH]-4.830)

The FAV in μg/L shall not exceed: exp.(1.005[pH]-4.1373)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For pH values less than 6.0, 6.0 shall be used to calculate the standard and for pH values greater than 9.0, 9.0 shall be used to calculate the standard.

Example of pentachlorophenol standards for five pH values:

pH su 6.5 7.0 7.5 8.0 8.5
_
Pentachlorophenol
CS μg/L 3.5 5.5 5.5 5.5 5.5
MS μg/L 5.5 9.1 15 25 41
FAV μg/L 11 18 30 50 82
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
pH, minimum su 6.5 NA -- -- NA
pH, maximum su 9.0 NA -- -- NA
Phenanthrene μg/L 3.6 Tox 32 64 Tox
Phenol μg/L 123 Tox 2,214 4,428 Tox
Polychlorinated
biphenyls, total (c)
ng/L 0.029 HH 1,000* 2,000* Tox
Radioactive materials NA See
below
NA See
below
See
below
NA

Not to exceed the lowest concentrations permitted to be discharged to an uncontrolled environment as permitted by the appropriate authority having control over their use.

Selenium, total μg/L 5.0 Tox 20 40 Tox
Silver, total μg/L 1.0 Tox equation equation Tox

The MS and FAV vary with total hardness and are calculated using the following equations:

The MS in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-7.2156)

The FAV in μg/L shall not exceed: exp.(1.720[ln(total hardness mg/L)]-6.520

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total silver standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Silver, total
CS μg/L 1.0 1.0 1.0 1.0 1.0
MS μg/L 1.0 2.0 6.7 13 22
FAV μg/L 1.2 4.1 13 27 44
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Temperature °F See
below
NA -- -- NA

5°F above natural in streams and 3°F above natural in lakes, based on monthly average of the maximum daily temperatures, except in no case shall it exceed the daily average temperature of 86°F.

1,1,2,2-Tetrachloroethane (c) μg/L 13 HH 1,127 2,253 Tox
Tetrachloroethylene (c) μg/L 8.9 HH 428 857 Tox
Thallium, total μg/L 0.56 HH 64 128 Tox
Toluene μg/L 253 Tox 1,352 2,703 Tox
Toxaphene (c) ng/L 1.3 HH 730* 1,500* Tox
1,1,1-Trichloroethane μg/L 329 Tox 2,957 5,913 Tox
1,1,2-Trichloroethylene (c) μg/L 120 HH 6,988 13,976 Tox
2,4,6-Trichlorophenol μg/L 2.0 HH 102 203 Tox
Total suspended solids (TSS)
North River Nutrient Region mg/L 15 NA -- -- NA
Central River Nutrient Region mg/L 30 NA -- -- NA
South River Nutrient Region mg/L 65 NA -- -- NA
Red River mainstem - headwaters to border mg/L 100 NA -- -- NA
TSS standards for the Class 2B North, Central, and South River Nutrient Regions and the Red River mainstem may be exceeded for no more than ten percent of the time. This standard applies April 1 through September 30
Total suspended solids (TSS), summer average
Lower Mississippi River mainstem - Pools 2 through 4 mg/L 32 NA -- -- NA
Lower Mississippi River mainstem below Lake Pepin mg/L 30 NA -- -- NA
TSS standards for the Class 2B Lower Mississippi River may be exceeded for no more than 50 percent of the time. This standard applies June 1 through September 30
Substance,
Characteristic,
or Pollutant
(Class 2B)
Units CS Basis
for
CS
MS FAV Basis
for MS,
FAV
_
Vinyl chloride (c) μg/L 9.2 HH --* --* NA
Xylene, total m,p,o μg/L 166 Tox 1,407 2,814 Tox
Zinc, total μg/L equation Tox equation equation Tox

The CS, MS, and FAV vary with total hardness and are calculated using the following equations:

The CS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.7615)

The MS in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+0.8604)

The FAV in μg/L shall not exceed: exp.(0.8473[ln(total hardness mg/L)]+1.5536)

Where: exp. is the natural antilogarithm (base e) of the expression in parenthesis.

For hardness values greater than 400 mg/L, 400 mg/L shall be used to calculate the standard.

Example of total zinc standards for five total hardness values:

TH in mg/L 50 100 200 300 400
_
Zinc, total
CS μg/L 59 106 191 269 343
MS μg/L 65 117 211 297 379
FAV μg/L 130 234 421 594 758

Subp. 4a.

Narrative eutrophication standards for Class 2B lakes, shallow lakes, and reservoirs.

A.

Eutrophication standards applicable to lakes, shallow lakes, and reservoirs that lie on the border between two ecoregions or that are in the Red River Valley (also referred to as Lake Agassiz Plains), Northern Minnesota Wetlands, or Driftless Area Ecoregion must be applied on a case-by-case basis. The commissioner shall use the standards applicable to adjacent ecoregions as a guide.

B.

Eutrophication standards are compared to summer-average data. Exceedance of the total phosphorus and either the chlorophyll-a or Secchi disk transparency standard is required to indicate a polluted condition.

C.

It is the policy of the agency to protect all lakes, shallow lakes, and reservoirs from the undesirable effects of cultural eutrophication. Lakes, shallow lakes, and reservoirs with a baseline quality better than the numeric eutrophication standards in subpart 4 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources, and the protection of lake, shallow lake, and reservoir resources, including, but not limited to:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

D.

Lakes, shallow lakes, and reservoirs with a baseline quality that is poorer than the numeric eutrophication standards in subpart 4 must be considered to be in compliance with the standards if the baseline quality is the result of natural causes. The commissioner shall determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

E.

When applied to reservoirs, the eutrophication standards in this subpart and subpart 4 may be modified on a site-specific basis to account for characteristics of reservoirs that can affect trophic status, such as water temperature, variations in hydraulic residence time, watershed size, and the fact that reservoirs may receive drainage from more than one ecoregion. Information supporting a site-specific standard can be provided by the commissioner or by any person outside the agency. The commissioner shall evaluate all data in support of a modified standard and determine whether a change in the standard for a specific reservoir is justified. Any total phosphorus effluent limit determined to be necessary based on a modified standard shall only be required after the discharger has been given notice of the specific proposed effluent limits and an opportunity to request a hearing as provided in part 7000.1800.

Subp. 4b.

Narrative eutrophication standards for Class 2B rivers and streams.

A.

Eutrophication standards for rivers and streams are compared to summer-average data or as specified in subpart 4. Exceedance of the total phosphorus levels and chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels is required to indicate a polluted condition.

B.

Rivers and streams that exceed the phosphorus levels but do not exceed the chlorophyll-a (seston), five-day biochemical oxygen demand (BOD5), diel dissolved oxygen flux, or pH levels meet the eutrophication standard.

C.

A polluted condition also exists when the chlorophyll-a (periphyton) concentration exceeds 150 mg/m2 more than one year in ten

D.

It is the policy of the agency to protect all rivers, streams, and navigational pools from the undesirable effects of cultural eutrophication. Rivers, streams, and navigational pools with a baseline quality better than the numeric eutrophication standards in subpart 4 must be maintained in that condition through the strict application of all relevant federal, state, and local requirements governing nondegradation, the discharge of nutrients from point and nonpoint sources, including:

(1)

the nondegradation requirements in parts 7050.0180 and 7050.0185;

(2)

the phosphorus effluent limits for point sources, where applicable in chapter 7053;

(3)

the requirements for feedlots in chapter 7020;

(4)

the requirements for individual sewage treatment systems in chapter 7080;

(5)

the requirements for control of storm water in chapter 7090;

(6)

county shoreland ordinances; and

(7)

implementation of mandatory and voluntary best management practices to minimize point and nonpoint sources of nutrients.

E.

Rivers, streams, and navigational pools with a baseline quality that does not meet the numeric eutrophication standards in subpart 4 are in compliance with the standards if the baseline quality is the result of natural causes. The commissioner must determine baseline quality and compliance with these standards using data and the procedures in part 7050.0150, subpart 5.

Subp. 5.

Class 2C waters.

The quality of Class 2C surface waters shall be such as to permit the propagation and maintenance of a healthy community of indigenous fish and associated aquatic life, and their habitats. These waters shall be suitable for boating and other forms of aquatic recreation for which the waters may be usable. The standards for Class 2B waters listed in subparts 4 and 4a shall apply to these waters except as listed below:

Substance, Characteristic, or Pollutant

Escherichia (E.) coli. Not to exceed 126 organisms per 100 milliliters as a geometric mean of not less than five samples representative of conditions within any calendar month, nor shall more than ten percent of all samples taken during any calendar month individually exceed 1,260 organisms per 100 milliliters. The standard applies only between April 1 and October 31.

Oxygen, dissolved. 5 mg/L as a daily minimum. This dissolved oxygen standard may be modified on a site-specific basis according to part 7050.0220, subpart 7, except that no site-specific standard shall be less than 5 mg/L as a daily average and 4 mg/L as a daily minimum. Compliance with this standard is required 50 percent of the days at which the flow of the receiving water is equal to the 7Q10.

This dissolved oxygen standard applies to all Class 2C waters except for those portions of the Mississippi River from the outlet of the metro wastewater treatment works in Saint Paul (River Mile 835) to Lock and Dam No. 2 at Hastings (River Mile 815) and except for the reach of the Minnesota River from the outlet of the Blue Lake wastewater treatment works (River Mile 21) to the mouth at Fort Snelling. For this reach of the Mississippi River the standard is not less than 5 mg/L as a daily average from April 1 through November 30, and not less than 4 mg/L at other times. For the specified reach of the Minnesota River the standard shall be not less than 5 mg/L as a daily average year-round.

Temperature. 5°F above natural in streams and 3°F above natural in lakes, based on monthly average of the maximum daily temperature, except in no case shall it exceed the daily average temperature of 90°F.

Subp. 6.

Class 2D waters; wetlands.

A.

The quality of Class 2D wetlands shall be such as to permit the propagation and maintenance of a healthy community of aquatic and terrestrial species indigenous to wetlands, and their habitats. Wetlands also add to the biological diversity of the landscape. These waters shall be suitable for boating and other forms of aquatic recreation for which the wetland may be usable. The standards for Class 2B waters listed under subpart 4 shall apply to these waters except as listed below:

Substance, Characteristic, or Pollutant Class 2D Standard
Oxygen, dissolved If background is less than 5.0 mg/L as a daily minimum, maintain background
pH Maintain background
Temperature Maintain background

B.

"Maintain background," as used in this subpart, means the concentration of the water quality substances, characteristics, or pollutants shall not deviate from the range of natural background concentrations or conditions such that there is a potential significant adverse impact to the designated uses.

C.

Activities in wetlands which involve the normal farm practices of planting with annually seeded crops or the utilization of a crop rotation seeding of pasture grasses or legumes, including the recommended applications of fertilizer and pesticides, are excluded from the standards in this subpart and the wetland standards in parts 7050.0224, subpart 4; 7050.0225, subpart 2; and 7050.0227. All other activities in these wetlands must meet water quality standards.

Subp. 7.

Additional standards; Class 2 waters.

The following additional standards and requirements apply to all Class 2 waters.

A.

No sewage, industrial waste, or other wastes from point or nonpoint sources shall be discharged into any of the waters of this category so as to cause any material change in any other substances, characteristics, or pollutants which may impair the quality of the waters of the state or the aquatic biota of any of the classes in subparts 2 to 6 or in any manner render them unsuitable or objectionable for fishing, fish culture, or recreational uses. Additional selective limits or changes in the discharge bases may be imposed on the basis of local needs.

B.

To prevent acutely toxic conditions, concentrations of toxic pollutants from point or nonpoint sources must not exceed the FAV as a one-day average at the point of discharge or in the surface water consistent with parts 7050.0210, subpart 5, item D; 7053.0215, subpart 1; 7053.0225, subpart 6; and 7053.0245, subpart 1.

If a discharge is composed of a mixture of more than one chemical, and the chemicals have the same mode of toxic action, the commissioner has the option to apply an additive model to determine the toxicity of the mixture using the following equation:

C 1
_
+ C 2
_
+ . + C n
_
equals a value of one or more, an
FAV1 FAV2 FAVn acutely toxic condition if indicated
where: C1 .... Cn is the concentration of the first to the nth toxicant.
FAV1 .... FAVn is the FAV for the first to the nth toxicant.

C.

To prevent chronically toxic conditions, concentrations of toxic pollutants must not exceed the applicable CS or CC and MS or MC in surface waters outside allowable mixing zones as described in part 7050.0210, subpart 5. The CS or CC and MS or MC will be averaged over the following durations: the MS or MC will be a one-day average; the CS or CC, based on toxicity to aquatic life, will be a four-day average; and the CS or CC, based on human health and applied in water or wildlife toxicity, will be a 30-day average.

D.

Concentrations of noncarcinogenic or nonlinear carcinogenic (NLC) chemicals in water or fish tissue from point or nonpoint sources, singly or in mixtures, must be below levels expected to produce known adverse effects. This is accomplished through the application of an additive noncancer health risk index using common health risk index endpoints or health endpoints. Mixtures of chemicals with listed CS or site-specific CC are evaluated using the following approach:

Chemicals must be grouped according to medium (water or fish) and each health endpoint. Chemicals for which no health endpoint is specified are not grouped. Chemicals that are also linear carcinogens must be grouped as described under item E. Using the following equation, a noncancer health risk index must be determined for each group of two or more chemicals that have a common health endpoint listed in this part. To meet the protection objectives in part 7050.0217, the noncancer health risk index must not exceed a value of one.

Noncancer health risk index by common health endpoint = C 1
_
+ C 2
_
+ ... + C n
_
≤ 1
CS1 or CC1 CS2 or CC2 CSn or CCn
where: Cn is the concentration of the first to the nth chemical by common health endpoint and medium
CS1 ... CSn is the drinking water plus fish consumption and recreation chronic standard (CSdfr or CSdev), fish consumption and recreation chronic standard (CSfr), or fish tissue chronic standard (CSft) for the first to nth chemical by common health endpoint
CC1 ... CCn is the drinking water plus fish consumption and recreation chronic criterion (CCdfr or CCdev), fish consumption and recreation chronic criterion (CCfr), or fish tissue chronic criterion (CCft) for the first to nth chemical by common health endpoint

E.

Concentrations of carcinogenic chemicals from point or nonpoint sources, singly or in mixtures, must not exceed an incremental or additional excess risk level of one in 100,000 (10-5) in surface waters or fish tissue. Carcinogenic chemicals will be considered additive in their effect according to the following equation unless an alternative model is supported by available scientific evidence. The additive equation applies to chemicals that have a human health-based chronic standard (CS) or site-specific chronic criterion (CC) calculated with a cancer potency slope factor. To meet the protection objectives in part 7050.0217, the cancer health risk index must not exceed a value of one.

Cancer health risk index = C 1
_
+ C 2
_
+ ... + C n
_
≤ 1
CS1 or CC1 CS2 or CC2 CSn or CCn
where: C1 .... Cn is the concentration of the first to the nth carcinogen in water or fish tissue
CS1 ... CSn is the drinking water plus fish consumption and recreation chronic standard (CSdfr), fish consumption and recreation chronic standard (CSfr), or fish tissue chronic standard (CSft) for the first to nth carcinogenic chemical
CC1 .... CCn is the drinking water plus fish consumption and recreation chronic criterion (CCdfr) fish consumption and recreation chronic criterion (CCfr), or fish tissue chronic criterion (CCft) for the first to nth carcinogenic chemical

F.

When monitoring indicates that chemical breakdown products or environmental degradates are present in surface water or fish tissue, those products must be considered when meeting the objectives for toxic pollutants in part 7050.0217. When no human health-based CS or other MDH health-based guidance is available for the chemical breakdown product, the CS or CC for the parent chemical must be applied for that product. The parent CS or CC must also be applied to evaluate mixtures of chemicals.

G.

This item applies to maximum standards (MS), final acute values (FAV), and double dashes (--) in this part and part 7050.0220 marked with an asterisk (*). For carcinogenic or highly bioaccumulative chemicals with BCFs greater than 5,000 or log Kow values greater than 5.19, the human health-based chronic standard (CS) may be two or more orders of magnitude smaller than the acute toxicity-based MS.

If the ratio of the MS to the CS is greater than 100, the CS times 100 must be substituted for the applicable MS, and the CS times 200 must be substituted for the applicable FAV. Any effluent limit derived using the procedures of this item must only be required after the discharger has been given notice of the specific proposed effluent limits and an opportunity to request a hearing as provided in part 7000.1800.

Subp. 8.

[Repealed, 32 SR 1699]

Subp. 9.

Conversion factors for dissolved metal standards.

Metal Conversion Factor for CS Conversion Factor for MS and FAV
Cadmium 0.909 1.1017-[(ln TH, mg/L) (0.0418)] 0.946 1.1367-[(ln TH, mg/L) (0.0418)]
Chromium +3 0.860 0.316
Chromium +6 0.962 0.982
Copper 0.960 0.960
Lead 0.791 1.4620-[(ln TH, mg/L) (0.1457)] 0.791 1.4620-[(ln TH, mg/L) (0.1457)]
Mercury 1.0 0.850
Nickel 0.997 0.998
Silver 0.850 0.850
Zinc 0.986 0.978

Conversion factors for cadmium and lead are hardness (TH) dependent. The factors shown in the table above are for a total hardness of 100 mg/L only. Conversion factors for cadmium and lead for other hardness values shall be calculated using the equations included in the table. The dissolved standard is the total standard times the conversion factor.

Statutory Authority:

MS s 14.06; 115.03; 115.44; 116.07

History:

18 SR 2195; 19 SR 1310; 24 SR 1105; 27 SR 1217; 32 SR 1699; 39 SR 154; 39 SR 1344

Published Electronically:

March 24, 2015

700 State Office Building, 100 Rev. Dr. Martin Luther King Jr. Blvd., St. Paul, MN 55155 ♦ Phone: (651) 296-2868 ♦ TTY: 1-800-627-3529 ♦ Fax: (651) 296-0569