40 CFR 131.14 (up to date as of 9/19/2023)

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Water quality standards variances.

40 CFR 131.14 (Sept. 19, 2023)

This content is from the eCFR and is authoritative but unofficial.

Title 40 —Protection of Environment

Chapter I —Environmental Protection Agency

Subchapter D —Water Programs

Part 131 —Water Quality Standards

Subpart B —Establishment of Water Quality Standards

Authority: 33 U.S.C. 1251 et seq.

Source: 48 FR 51405, Nov. 8, 1983, unless otherwise noted.

§ 131.14 Water quality standards variances.

States may adopt WQS variances, as defined in § 131.3(o). Such a WQS variance is subject to the provisions of this

section and public participation requirements at § 131.20(b). A WQS variance is a water quality standard subject to

EPA review and approval or disapproval.

(a) Applicability.

(1) A WQS variance may be adopted for a permittee(s) or water body/waterbody segment(s), but only

applies to the permittee(s) or water body/waterbody segment(s) specified in the WQS variance.

(2) Where a State adopts a WQS variance, the State must retain, in its standards, the underlying

designated use and criterion addressed by the WQS variance, unless the State adopts and EPA

approves a revision to the underlying designated use and criterion consistent with §§ 131.10 and

131.11. All other applicable standards not specifically addressed by the WQS variance remain

applicable.

(3) A WQS variance, once adopted by the State and approved by EPA, shall be the applicable standard

for purposes of the Act under § 131.21(d) through (e), for the following limited purposes. An

approved WQS variance applies for the purposes of developing NPDES permit limits and

requirements under 301(b)(1)(C), where appropriate, consistent with paragraph (a)(1) of this section.

States and other certifying entities may also use an approved WQS variance when issuing

certifications under section 401 of the Act.

(4) A State may not adopt WQS variances if the designated use and criterion addressed by the WQS

variance can be achieved by implementing technology-based effluent limits required under sections

301(b) and 306 of the Act.

(b) Requirements for Submission to EPA.

(1) A WQS variance must include:

(i)

Identification of the pollutant(s) or water quality parameter(s), and the water body/waterbody

segment(s) to which the WQS variance applies. Discharger(s)-specific WQS variances must

also identify the permittee(s) subject to the WQS variance.

(ii) The requirements that apply throughout the term of the WQS variance. The requirements shall

represent the highest attainable condition of the water body or waterbody segment applicable

throughout the term of the WQS variance based on the documentation required in (b)(2) of this

section. The requirements shall not result in any lowering of the currently attained ambient

40 CFR 131.14(b)(1)(ii) (enhanced display)

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40 CFR 131.14 (up to date as of 9/19/2023)

Water quality standards variances.

40 CFR 131.14(b)(1)(ii)(A)

water quality, unless a WQS variance is necessary for restoration activities, consistent with

paragraph (b)(2)(i)(A)(2) of this section. The State must specify the highest attainable condition

of the water body or waterbody segment as a quantifiable expression that is one of the

following:

(A) For discharger(s)-specific WQS variances:

(1) The highest attainable interim criterion; or

(2) The interim effluent condition that reflects the greatest pollutant reduction

achievable; or

(3) If no additional feasible pollutant control technology can be identified, the interim

criterion or interim effluent condition that reflects the greatest pollutant reduction

achievable with the pollutant control technologies installed at the time the State

adopts the WQS variance, and the adoption and implementation of a Pollutant

Minimization Program.

(B) For WQS variances applicable to a water body or waterbody segment:

(1) The highest attainable interim use and interim criterion; or

(2) If no additional feasible pollutant control technology can be identified, the interim use

and interim criterion that reflect the greatest pollutant reduction achievable with the

pollutant control technologies installed at the time the State adopts the WQS

variance, and the adoption and implementation of a Pollutant Minimization Program.

(iii) A statement providing that the requirements of the WQS variance are either the highest

attainable condition identified at the time of the adoption of the WQS variance, or the highest

attainable condition later identified during any reevaluation consistent with paragraph (b)(1)(v)

of this section, whichever is more stringent.

(iv) The term of the WQS variance, expressed as an interval of time from the date of EPA approval

or a specific date. The term of the WQS variance must only be as long as necessary to achieve

the highest attainable condition and consistent with the demonstration provided in paragraph

(b)(2) of this section. The State may adopt a subsequent WQS variance consistent with this

section.

(v) For a WQS variance with a term greater than five years, a specified frequency to reevaluate the

highest attainable condition using all existing and readily available information and a provision

specifying how the State intends to obtain public input on the reevaluation. Such reevaluations

must occur no less frequently than every five years after EPA approval of the WQS variance and

the results of such reevaluation must be submitted to EPA within 30 days of completion of the

reevaluation.

(vi) A provision that the WQS variance will no longer be the applicable water quality standard for

purposes of the Act if the State does not conduct a reevaluation consistent with the frequency

specified in the WQS variance or the results are not submitted to EPA as required by (b)(1)(v) of

this section.

(2) The supporting documentation must include:

(i)

Documentation demonstrating the need for a WQS variance.

40 CFR 131.14(b)(2)(i) (enhanced display)

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40 CFR 131.14 (up to date as of 9/19/2023)

Water quality standards variances.

40 CFR 131.14(b)(2)(i)(A)

(A) For a WQS variance to a use specified in section 101(a)(2) of the Act or a sub-category of

such a use, the State must demonstrate that attaining the designated use and criterion is

not feasible throughout the term of the WQS variance because:

(1) One of the factors listed in § 131.10(g) is met, or

(2) Actions necessary to facilitate lake, wetland, or stream restoration through dam

removal or other significant reconfiguration activities preclude attainment of the

designated use and criterion while the actions are being implemented.

(B) For a WQS variance to a non-101(a)(2) use, the State must submit documentation

justifying how its consideration of the use and value of the water for those uses listed in §

131.10(a) appropriately supports the WQS variance and term. A demonstration consistent

with paragraph (b)(2)(i)(A) of this section may be used to satisfy this requirement.

(ii) Documentation demonstrating that the term of the WQS variance is only as long as necessary

to achieve the highest attainable condition. Such documentation must justify the term of the

WQS variance by describing the pollutant control activities to achieve the highest attainable

condition, including those activities identified through a Pollutant Minimization Program, which

serve as milestones for the WQS variance.

(iii) In addition to paragraphs (b)(2)(i) and (ii) of this section, for a WQS variance that applies to a

water body or waterbody segment:

(A) Identification and documentation of any cost-effective and reasonable best management

practices for nonpoint source controls related to the pollutant(s) or water quality

parameter(s) and water body or waterbody segment(s) specified in the WQS variance that

could be implemented to make progress towards attaining the underlying designated use

and criterion. A State must provide public notice and comment for any such

documentation.

(B) Any subsequent WQS variance for a water body or waterbody segment must include

documentation of whether and to what extent best management practices for nonpoint

source controls were implemented to address the pollutant(s) or water quality

parameter(s) subject to the WQS variance and the water quality progress achieved.

standard for implementing NPDES permitting requirements pursuant to § 122.44(d) of this chapter for the

term of the WQS variance. Any limitations and requirements necessary to implement the WQS variance

shall be included as enforceable conditions of the NPDES permit for the permittee(s) subject to the WQS

variance.

[80 FR 51048, Aug. 21, 2015]

40 CFR 131.14(c) (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

Appendix B to Part 132, Title 40 (Feb. 1, 2024)

This content is from the eCFR and is authoritative but unofficial.

Title 40 —Protection of Environment

Chapter I —Environmental Protection Agency

Subchapter D —Water Programs

Part 132 —Water Quality Guidance for the Great Lakes System

Authority: 33 U.S.C. 1251 et seq.

Source: 60 FR 15387, Mar. 23, 1995, unless otherwise noted.

Appendix B to Part 132—Great Lakes Water Quality Initiative

Methodology for Deriving Bioaccumulation Factors

Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this appendix.

I. Introduction

The purpose of this methodology is to describe procedures for deriving bioaccumulation factors

(BAFs) to be used in the calculation of Great Lakes Water Quality Guidance (Guidance) human health

Tier I criteria and Tier II values and wildlife Tier I criteria. A subset of the human health BAFs are also

used to identify the chemicals that are considered bioaccumulative chemicals of concern (BCCs).

Bioaccumulation reflects uptake of a substance by aquatic organisms exposed to the substance

through all routes (i.e., ambient water and food), as would occur in nature. Bioconcentration reflects

uptake of a substance by aquatic organisms exposed to the substance only through the ambient

water. Both BAFs and bioconcentration factors (BCFs) are proportionality constants that describe

the relationship between the concentration of a substance in aquatic organisms and its

concentration in the ambient water. For the Guidance in this part, BAFs, rather than BCFs, are used to

calculate Tier I criteria for human health and wildlife and Tier II values for human health because

they better account for the total exposure of aquatic organisms to chemicals.

For organic chemicals, baseline BAFs can be derived using four methods. Measured baseline BAFs

are derived from field-measured BAFs; predicted baseline BAFs are derived using biota-sediment

accumulation factors (BSAFs) or are derived by multiplying a laboratory-measured or predicted BCF

by a food-chain multiplier (FCM). The lipid content of the aquatic organisms is used to account for

partitioning of organic chemicals within organisms so that data from different tissues and species

can be integrated. In addition, the baseline BAF is based on the concentration of freely dissolved

organic chemicals in the ambient water to facilitate extrapolation from one water to another.

For inorganic chemicals, baseline BAFs can be derived using two of the four methods. Baseline BAFs

are derived using either field-measured BAFs or by multiplying laboratory-measured BCFs by a FCM.

For inorganic chemicals, BAFs are assumed to equal BCFs (i.e., the FCM is 1.0), unless chemicalspecific biomagnification data support using a FCM other than 1.0.

Because both humans and wildlife consume fish from both trophic levels 3 and 4, two baseline BAFs

are needed to calculate either a human health criterion or value or a wildlife criterion for a chemical.

When appropriate, ingestion through consumption of invertebrates, plants, mammals, and birds in

the diet of wildlife species to be protected may be taken into account.

40 CFR Appendix-B-to-Part-132 I.E. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 II. “Baseline BAF”

II. Definitions

Baseline BAF. For organic chemicals, a BAF that is based on the concentration of freely dissolved chemical

in the ambient water and takes into account the partitioning of the chemical within the organism; for

inorganic chemicals, a BAF that is based on the wet weight of the tissue.

Baseline BCF. For organic chemicals, a BCF that is based on the concentration of freely dissolved chemical

in the ambient water and takes into account the partitioning of the chemical within the organism; for

inorganic chemicals, a BCF that is based on the wet weight of the tissue.

Bioaccumulation. The net accumulation of a substance by an organism as a result of uptake from all

environmental sources.

Bioaccumulation factor (BAF). The ratio (in L/kg) of a substance's concentration in tissue of an aquatic

organism to its concentration in the ambient water, in situations where both the organism and its

food are exposed to and the ratio does not change substantially over time.

Bioconcentration. The net accumulation of a substance by an aquatic organism as a result of uptake

directly from the ambient water through gill membranes or other external body surfaces.

Bioconcentration factor (BCF). The ratio (in L/kg) of a substance's concentration in tissue of an aquatic

organism to its concentration in the ambient water, in situations where the organism is exposed

through the water only and the ratio does not change substantially over time.

Biota-sediment accumulation factor (BSAF). The ratio (in kg of organic carbon/kg of lipid) of a substance's

lipid-normalized concentration in tissue of an aquatic organism to its organic carbon-normalized

concentration in surface sediment, in situations where the ratio does not change substantially over

time, both the organism and its food are exposed, and the surface sediment is representative of

average surface sediment in the vicinity of the organism.

Depuration. The loss of a substance from an organism as a result of any active or passive process.

Food-chain multiplier (FCM). The ratio of a BAF to an appropriate BCF.

Octanol-water partition coefficient (KOW). The ration of the concentration of a substance in the n-octanol

phase to its concentration in the aqueous phase in an equilibrated two-phase octanol-water system.

For log KOW, the log of the octanol-water partition coefficient is a base 10 logarithm.

Uptake. Acquisition of a substance from the environment by an organism as a result of any active or

passive process.

III. Review and Selection of Data

Data Sources. Measured BAFs, BSAFs and BCFs are assembled from available sources including the

following:

EPA Ambient Water Quality Criteria documents issued after January 1, 1980.

Published scientific literature.

Reports issued by EPA or other reliable sources.

Unpublished data.

40 CFR Appendix-B-to-Part-132 III.A.4. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 III.B.

One useful source of references is the Aquatic Toxicity Information Retrieval (AQUIRE)

database.

Field-Measured BAFs. The following procedural and quality assurance requirements shall be met for

field-measured BAFs:

The field studies used shall be limited to those conducted in the Great Lakes System with fish at

or near the top of the aquatic food chain (i.e., in trophic levels 3 and/or 4).

The trophic level of the fish species shall be determined.

The site of the field study should not be so unique that the BAF cannot be extrapolated to other

locations where the criteria and values will apply.

For organic chemicals, the percent lipid shall be either measured or reliably estimated for the

tissue used in the determination of the BAF.

The concentration of the chemical in the water shall be measured in a way that can be related

to particulate organic carbon (POC) and/or dissolved organic carbon (DOC) and should be

relatively constant during the steady-state time period.

For organic chemicals with log KOW greater than four, the concentrations of POC and DOC in the

ambient water shall be either measured or reliably estimated.

For inorganic and organic chemicals, BAFs shall be used only if they are expressed on a wet

weight basis; BAFs reported on a dry weight basis cannot be converted to wet weight unless a

conversion factor is measured or reliably estimated for the tissue used in the determination of

the BAF.

Field-Measured BSAFs. The following procedural and quality assurance requirements shall be met

for field-measured BSAFs:

The field studies used shall be limited to those conducted in the Great Lakes System with fish at

or near the top of the aquatic food chain (i.e., in trophic levels 3 and/or 4).

Samples of surface sediments (0–1 cm is ideal) shall be from locations in which there is net

deposition of fine sediment and is representative of average surface sediment in the vicinity of

the organism.

The KOW s used shall be acceptable quality as described in section III.F below.

The site of the field study should not be so unique that the resulting BAF cannot be extrapolated

to other locations where the criteria and values will apply.

The tropic level of the fish species shall be determined.

The percent lipid shall be either measured or reliably estimated for the tissue used in the

determination of the BAF.

Laboratory-Measured BCFs. The following procedural and quality assurance requirements shall be

met for laboratory-measured BCFs:

The test organism shall not be diseased, unhealthy, or adversely affected by the concentration

of the chemical.

40 CFR Appendix-B-to-Part-132 III.D.1. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 III.D.2.

The total concentration of the chemical in the water shall be measured and should be relatively

constant during the steady-state time period.

The organisms shall be exposed to the chemical using a flow-through or renewal procedure.

For organic chemicals, the percent lipid shall be either measured or reliably estimated for the

tissue used in the determination of the BCF.

For organic chemicals with log KOW greater than four, the concentrations of POC and DOC in the

test solution shall be either measured or reliably estimated.

Laboratory-measured BCFs should be determined using fish species, but BCFs determined with

molluscs and other invertebrates may be used with caution. For example, because

invertebrates metabolize some chemicals less efficiently than vertebrates, a baseline BCF

determined for such a chemical using invertebrates is expected to be higher than a comparable

baseline BCF determined using fish.

If laboratory-measured BCFs increase or decrease as the concentration of the chemical

increases in the test solutions in a bioconcentration test, the BCF measured at the lowest test

concentration that is above concentrations existing in the control water shall be used (i.e., a

BCF should be calculated from a control treatment). The concentrations of an inorganic

chemical in a bioconcentration test should be greater than normal background levels and

greater than levels required for normal nutrition of the test species if the chemical is a

micronutrient, but below levels that adversely affect the species. Bioaccumulation of an

inorganic chemical might be overestimated if concentrations are at or below normal

background levels due to, for example, nutritional requirements of the test organisms.

For inorganic and organic chemicals, BCFs shall be used only if they are expressed on a wet

weight basis. BCFs reported on a dry weight basis cannot be converted to wet weight unless a

conversion factor is measured or reliably estimated for the tissue used in the determination of

the BAF.

BCFs for organic chemicals may be based on measurement or radioactivity only when the BCF

is intended to include metabolites or when there is confidence that there is no interference due

to metabolites.

10. The calculation of the BCF must appropriately address growth dilution.

11. Other aspects of the methodology used should be similar to those described by ASTM (1990).

Predicted BCFs. The following procedural and quality assurance requirements shall be met for

predicted BCFs:

The KOW used shall be of acceptable quality as described in section III.F below.

The predicted baseline BCF shall be calculated using the equation: predicted baseline BCF =

KOW

where:

KOW = octanol-water partition coefficient.

Octanol-Water Partition Coefficient (K OW).

40 CFR Appendix-B-to-Part-132 III.F. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 III.F.1.

The value of KOW used for an organic chemical shall be determined by giving priority to the

experimental and computational techniques used as follows:

Log KOW <4:

Priority

Technique

Slow-stir.

Generator-column.

Shake-flask.

Reverse-phase liquid chromatography on C18 chromatography packing with extrapolation to

zero percent solvent.

Reverse-phase liquid chromatography on C18 chromatography packing without extrapolation

to zero percent solvent.

Calculated by the CLOGP program.

Log KOW >4:

Priority

Technique

Slow Stir.

Generator-column.

Reverse-phase liquid chromatography on C18 chromatography packing with extrapolation to

zero percent solvent.

Reverse-phase liquid chromatography on C18 chromatography packing without extrapolation

to zero percent solvent.

Shake-flask.

Calculated by the CLOGP program.

The CLOGP program is a computer program available from Pomona College. A value of KOW

that seems to be different from the others should be considered an outlier and not used. The

value of KOW used for an organic chemical shall be the geometric mean of the available KOW s

with highest priority or can be calculated from the arithmetic mean of the available log KOW with

the highest priority. Because it is an intermediate value in the derivation of a BAF, the value used

for the KOW of a chemical should not be rounded to fewer than three significant digits and a

value for log KOW should not be rounded to fewer than three significant digits after the decimal

point.

This methodology provides overall guidance for the derivation of BAFs, but it cannot cover all the

decisions that must be made in the review and selection of acceptable data. Professional judgment

is required throughout the process. A degree of uncertainty is associated with the determination of

any BAF, BSAF, BCF or KOW. The amount of uncertainty in a baseline BAF depends on both the quality

of data available and the method used to derive the BAF.

Hereinafter in this methodology, the terms BAF, BSAF, BCF and KOW refer to ones that are consistent

with the procedural and quality assurance requirements given above.

IV. Four Methods for Deriving Baseline BAFs

40 CFR Appendix-B-to-Part-132 III.H. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 IV.A.

Baseline BAFs shall be derived using the following four methods, which are listed from most preferred to

least preferred:

A measured baseline BAF for an organic or inorganic chemical derived from a field study of

acceptable quality.

A predicted baseline BAF for an organic chemical derived using field-measured BSAFs of acceptable

quality.

A predicted baseline BAF for an organic or inorganic chemical derived from a BCF measured in a

laboratory study of acceptable quality and a FCM.

A predicted baseline BAF for an organic chemical derived from a KOW of acceptable quality and a

FCM.

For comparative purposes, baseline BAFs should be derived for each chemical by as many of the

four methods as available data allow.

V. Calculation of Baseline BAFs for Organic Chemicals

Lipid Normalization.

It is assumed that BAFs and BCFs for organic chemicals can be extrapolated on the basis of

percent lipid from one tissue to another and from one aquatic species to another in most

cases.

Because BAFs and BCFs for organic chemicals are related to the percent lipid, it does not make

any difference whether the tissue sample is whole body or edible portion, but both the BAF (or

BCF) and the percent lipid must be determined for the same tissue. The percent lipid of the

tissue should be measured during the BAF or BCF study, but in some cases it can be reliably

estimated from measurements on tissue from other organisms. If percent lipid is not reported

for the test organisms in the original study, it may be obtained from the author; or, in the case of

a laboratory study, lipid data for the same or a comparable laboratory population of test

organisms that were used in the original study may be used.

The lipid-normalized concentration, Cl, of a chemical in tissue is defined using the following

equation:

Where:

CB = concentration of the organic chemical in the tissue of aquatic biota (either whole organism

or specified tissue) (µg/g).

fl = fraction of the tissue that is lipid.

Bioavailability. By definition, baseline BAFs and BCFs for organic chemicals, whether measured or

predicted are based on the concentration of the chemical that is freely dissolved in the ambient

water in order to account for bioavailability. For the purposes of this Guidance in this part, the

relationship between the total concentration of the chemical in the water (i.e., that which is freely

40 CFR Appendix-B-to-Part-132 V.B. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 V.C.

dissolved plus that which is sorbed to particulate organic carbon or to dissolved organic carbon) to

the freely dissolved concentration of the chemical in the ambient water shall be calculated using the

following equation:

Where:

Cfdw = freely dissolved concentration of the organic chemical in the ambient water;

Ctw = total concentration of the organic chemical in the ambient water;

ffd = fraction of the total chemical in the ambient water that is freely dissolved.

The fraction of the total chemical in the ambient water that is freely dissolved, ffd, shall be calculated

using the following equation:

Where:

DOC = concentration of dissolved organic carbon, kg of dissolved organic carbon/L of water.

KOW = octanol-water partition coefficient of the chemical.

POC = concentration of particulate organic carbon, kg of particulate organic carbon/L of water.

Food-Chain Multiplier. In the absence of a field-measured BAF or a predicted BAF derived from a

BSAF, a FCM shall be used to calculate the baseline BAF for trophic levels 3 and 4 from a laboratorymeasured or predicted BCF. For an organic chemical, the FCM used shall be derived from Table B–1

using the chemical's log KOW and linear interpolation. A FCM greater than 1.0 applies to most organic

chemicals with a log KOW of four or more. The trophic level used shall take into account the age or

size of the fish species consumed by the human, avian or mammalian predator because, for some

species of fish, the young are in trophic level 3 whereas the adults are in trophic level 4.

Calculation of a Baseline BAF from a Field-Measured BAF. A baseline BAF shall be calculated from a

field-measured BAF of acceptable quality using the following equation:

Where:

BAFtT = BAF based on total concentration in tissue and water.

fl = fraction of the tissue that is lipid.

40 CFR Appendix-B-to-Part-132 V.D. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 V.E.

ffd = fraction of the total chemical that is freely dissolved in the ambient water.

The trophic level to which the baseline BAF applies is the same as the trophic level of the organisms used

in the determination of the field-measured BAF. For each trophic level, a species mean measured baseline

BAF shall be calculated as the geometric mean if more than one measured baseline BAF is available for a

given species. For each trophic level, the geometric mean of the species mean measured baseline BAFs

shall be calculated. If a baseline BAF based on a measured BAF is available for either trophic level 3 or 4,

but not both, a measured baseline BAF for the other trophic level shall be calculated using the ratio of the

FCMs that are obtained by linear interpolation from Table B–1 for the chemical.

Calculation of a Baseline BAF from a Field-Measured BSAF.

A baseline BAF for organic chemical “i” shall be calculated from a field-measured BSAF of

acceptable quality using the following equation:

Where:

(BSAF)i = BSAF for chemical “i”.

(BSAF)r = BSAF for the reference chemical “r”.

(KOW)i = octanol-water partition coefficient for chemical “i”.

(KOW)r = octanol-water partition coefficient for the reference chemical “r”.

A BSAF shall be calculated using the following equation:

Where:

Ct = the lipid-normalized concentration of the chemical in tissue.

CSOC = the organic carbon-normalized concentration of the chemical in sediment.

The organic carbon-normalized concentration of a chemical in sediment, CSOC, shall be

calculated using the following equation:

Where:

CS = concentration of chemical in sediment (µg/g sediment).

fOC = fraction of the sediment that is organic carbon.

40 CFR Appendix-B-to-Part-132 V.E.3. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 V.E.4.

Predicting BAFs from BSAFs requires data from a steady-state (or near steady-state) condition

between sediment and ambient water for both a reference chemical “r” with a field-measured

BAFl fd and other chemicals “n = i” for which BSAFs are to be determined.

The trophic level to which the baseline BAF applies is the same as the trophic level of the

organisms used in the determination of the BSAF. For each trophic level, a species mean

baseline BAF shall be calculated as the geometric mean if more than one baseline BAF is

predicted from BSAFs for a given species. For each trophic level, the geometric mean of the

species mean baseline BAFs derived using BSAFs shall be calculated.

If a baseline BAF based on a measured BSAF is available for either trophic level 3 or 4, but not

both, a baseline BAF for the other trophic level shall be calculated using the ratio of the FCMs

that are obtained by linear interpolation from Table B–1 for the chemical.

Calculation of a Baseline BAF from a Laboratory-Measured BCF. A baseline BAF for trophic level 3 and

a baseline BAF for trophic level 4 shall be calculated from a laboratory-measured BCF of acceptable

quality and a FCM using the following equation:

Where:

BCFtT = BCF based on total concentration in tissue and water.

fl = fraction of the tissue that is lipid.

ffd = fraction of the total chemical in the test water that is freely dissolved.

FCM = the food-chain multiplier obtained from Table B–1 by linear interpolation for trophic level 3 or

4, as necessary.

For each trophic level, a species mean baseline BAF shall be calculated as the geometric mean if more

than one baseline BAF is predicted from laboratory-measured BCFs for a given species. For each trophic

level, the geometric mean of the species mean baseline BAFs based on laboratory-measured BCFs shall

be calculated.

Calculation of a Baseline BAF from an Octanol-Water Partition Coefficient. A baseline BAF for trophic

level 3 and a baseline BAF for trophic level 4 shall be calculated from a KOW of acceptable quality

and a FCM using the following equation:

Baseline BAF = (FCM) (predicted baseline BCF) = (FCM) (KOW)

Where:

FCM = the food-chain multiplier obtained from Table B–1 by linear interpolation for trophic level 3 or

4, as necessary.

KOW = octanol-water partition coefficient.

40 CFR Appendix-B-to-Part-132 V.G. (enhanced display)

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Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 VI.A.

VI. Human Health and Wildlife BAFs for Organic Chemicals

To calculate human health and wildlife BAFs for an organic chemical, the KOW of the chemical shall

be used with a POC concentration of 0.00000004 kg/L and a DOC concentration of 0.000002 kg/L to

yield the fraction freely dissolved:

The human health BAFs for an organic chemical shall be calculated using the following equations:

For trophic level 3:

For trophic level 4:

Where:

0.0182 and 0.0310 are the standardized fraction lipid values for trophic levels 3 and 4, respectively,

that are used to derive human health criteria and values for the GLI.

The wildlife BAFs for an organic chemical shall be calculated using the following equations:

For trophic level 3:

For trophic level 4:

Where:

0.0646 and 0.1031 are the standardized fraction lipid values for trophic levels 3 and 4, respectively,

that are used to derive wildlife criteria for the GLI.

40 CFR Appendix-B-to-Part-132 VI.C. (enhanced display)

page 10 of 13

Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 VII.A.

VII. Human Health and Wildlife BAFs for Inorganic Chemicals

For inorganic chemicals, the baseline BAFs for trophic levels 3 and 4 are both assumed to equal the

BCF determined for the chemical with fish, i.e., the FCM is assumed to be 1 for both trophic levels 3

and 4. However, a FCM greater than 1 might be applicable to some metals, such as mercury, if, for

example, an organometallic form of the metal biomagnifies.

BAFs for Human Health Criteria and Values.

Measured BAFs and BCFs used to determine human health BAFs for inorganic chemicals shall

be based on edible tissue (e.g., muscle) of freshwater fish unless it is demonstrated that wholebody BAFs or BCFs are similar to edible-tissue BAFs or BCFs. BCFs and BAFs based on

measurements of aquatic plants and invertebrates should not be used in the derivation of

human health criteria and values.

If one or more field-measured baseline BAFs for an inorganic chemical are available from

studies conducted in the Great Lakes System with the muscle of fish:

For each trophic level, a species mean measured baseline BAF shall be calculated as the

geometric mean if more than one measured BAF is available for a given species; and

For each trophic level, the geometric mean of the species mean measured baseline BAFs

shall be used as the human health BAF for that chemical.

If an acceptable measured baseline BAF is not available for an inorganic chemical and one or

more acceptable edible-portion laboratory-measured BCFs are available for the chemical, a

predicted baseline BAF shall be calculated by multiplying the geometric mean of the BCFs

times a FCM. The FCM will be 1.0 unless chemical-specific biomagnification data support using

a multiplier other than 1.0. The predicted baseline BAF shall be used as the human health BAF

for that chemical.

BAFs for Wildlife Criteria.

Measured BAFs and BCFs used to determine wildlife BAFs for inorganic chemicals shall be

based on whole-body freshwater fish and invertebrate data unless it is demonstrated that

edible-tissue BAFs or BCFs are similar to whole-body BAFs or BCFs.

If one or more field-measured baseline BAFs for an inorganic chemical are available from

studies conducted in the Great Lakes System with whole body of fish or invertebrates:

For each trophic level, a species mean measured baseline BAF shall be calculated as the

geometric mean if more than one measured BAF is available for a given species.

For each trophic level, the geometric mean of the species mean measured baseline BAFs

shall be used as the wildlife BAF for that chemical.

If an acceptable measured baseline BAF is not available for an inorganic chemical and one or

more acceptable whole-body laboratory-measured BCFs are available for the chemical, a

predicted baseline BAF shall be calculated by multiplying the geometric mean of the BCFs

times a FCM. The FCM will be 1.0 unless chemical-specific biomagnification data support using

a multiplier other than 1.0. The predicted baseline BAF shall be used as the wildlife BAF for that

chemical.

40 CFR Appendix-B-to-Part-132 VII.C.3. (enhanced display)

page 11 of 13

Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

40 CFR Appendix-B-to-Part-132 VII.C.3.

VIII. Final Review

For both organic and inorganic chemicals, human health and wildlife BAFs for both trophic levels shall be

reviewed for consistency with all available data concerning the bioaccumulation, bioconcentration, and

metabolism of the chemical. For example, information concerning octanol-water partitioning, molecular

size, or other physicochemical properties that might enhance or inhibit bioaccumulation should be

considered for organic chemicals. BAFs derived in accordance with this methodology should be modified

if changes are justified by available data.

IX. Literature Cited

ASTM. 1990. Standard Practice for Conducting Bioconcentration Tests with Fishes and Saltwater Bivalve Molluscs.

Standard E 1022. American Society for Testing and Materials, Philadelphia, PA.

Table B–1—Food-Chain Multipliers for Trophic Levels 2, 3 & 4

Log KOW

Trophic1 level 3

Trophic level 2

Trophic level 4

2.0

1.000

1.005

1.000

2.5

1.000

1.010

1.002

3.0

1.000

1.028

1.007

3.1

1.000

1.034

1.007

3.2

1.000

1.042

1.009

3.3

1.000

1.053

1.012

3.4

1.000

1.067

1.014

3.5

1.000

1.083

1.019

3.6

1.000

1.103

1.023

3.7

1.000

1.128

1.033

3.8

1.000

1.161

1.042

3.9

1.000

1.202

1.054

4.0

1.000

1.253

1.072

4.1

1.000

1.315

1.096

4.2

1.000

1.380

1.130

4.3

1.000

1.491

1.178

4.4

1.000

1.614

1.242

4.5

1.000

1.766

1.334

4.6

1.000

1.950

1.459

4.7

1.000

2.175

1.633

4.8

1.000

2.452

1.871

4.9

1.000

2.780

2.193

5.0

1.000

3.181

2.612

5.1

1.000

3.643

3.162

5.2

1.000

4.188

3.873

5.3

1.000

4.803

4.742

40 CFR Appendix-B-to-Part-132 VII.C.3. (enhanced display)

page 12 of 13

Appendix B to Part 132, Title 40 (up to date as of 2/01/2024)

Great Lakes Water Quality Initiative

Log KOW

40 CFR Appendix-B-to-Part-132 VII.C.3.

Trophic1 level 3

Trophic level 2

Trophic level 4

5.4

1.000

5.502

5.821

5.5

1.000

6.266

7.079

5.6

1.000

7.096

8.551

5.7

1.000

7.962

10.209

5.8

1.000

8.841

12.050

5.9

1.000

9.716

13.964

6.0

1.000

10.556

15.996

6.1

1.000

11.337

17.783

6.2

1.000

12.064

19.907

6.3

1.000

12.691

21.677

6.4

1.000

13.228

23.281

6.5

1.000

13.662

24.604

6.6

1.000

13.980

25.645

6.7

1.000

14.223

26.363

6.8

1.000

14.355

26.669

6.9

1.000

14.388

26.669

7.0

1.000

14.305

26.242

7.1

1.000

14.142

25.468

7.2

1.000

13.852

24.322

7.3

1.000

13.474

22.856

7.4

1.000

12.987

21.038

7.5

1.000

12.517

18.967

7.6

1.000

11.708

16.749

7.7

1.000

10.914

14.388

7.8

1.000

10.069

12.050

7.9

1.000

9.162

9.840

8.0

1.000

8.222

7.798

8.1

1.000

7.278

6.012

8.2

1.000

6.361

4.519

8.3

1.000

5.489

3.311

8.4

1.000

4.683

2.371

8.5

1.000

3.949

1.663

8.6

1.000

3.296

1.146

8.7

1.000

2.732

0.778

8.8

1.000

2.246

0.521

8.9

1.000

1.837

0.345

9.0

1.000

1.493

0.226

The FCMs for trophic level 3 are the geometric mean of the FCMs for sculpin and alewife.

40 CFR Appendix-B-to-Part-132 VII.C.3. (enhanced display)

page 13 of 13

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

Appendix F to Part 132, Title 40 (Sept. 19, 2023)

This content is from the eCFR and is authoritative but unofficial.

Title 40 —Protection of Environment

Chapter I —Environmental Protection Agency

Subchapter D —Water Programs

Part 132 —Water Quality Guidance for the Great Lakes System

Authority: 33 U.S.C. 1251 et seq.

Source: 60 FR 15387, Mar. 23, 1995, unless otherwise noted.

Appendix F to Part 132—Great Lakes Water Quality Initiative Implementation Procedures

Procedure 1: Site-specific Modifications to Criteria and Values

Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this procedure.

A. Requirements for Site-specific Modifications to Criteria and Values. Criteria and values may be modified on a

site-specific basis to reflect local environmental conditions as restricted by the following provisions. Any

such modifications must be protective of designated uses and aquatic life, wildlife or human health and

be submitted to EPA for approval. In addition, any site-specific modifications that result in less stringent

criteria must be based on a sound scientific rationale and shall not be likely to jeopardize the continued

existence of endangered or threatened species listed or proposed under section 4 of the Endangered

Species Act (ESA) or result in the destruction or adverse modification of such species' critical habitat.

More stringent modifications shall be developed to protect endangered or threatened species listed or

proposed under section 4 of the ESA, where such modifications are necessary to ensure that water quality

is not likely to jeopardize the continued existence of such species or result in the destruction or adverse

modification of such species' critical habitat. More stringent modifications may also be developed to

protect candidate (C1) species being considered by the U.S. Fish and Wildlife Service (FWS) for listing

under section 4 of the ESA, where such modifications are necessary to protect such species.

Aquatic Life.

Aquatic life criteria or values may be modified on a site-specific basis to provide an additional

level of protection, pursuant to authority reserved to the States and Tribes under Clean Water

Act (CWA) section 510.

Guidance on developing site-specific criteria in these instances is provided in Chapter 3 of the

U.S. EPA Water Quality Standards Handbook, Second Edition—Revised (1994).

Less stringent site-specific modifications to chronic or acute aquatic life criteria or values may

be developed when:

The local water quality characteristics such as Ph, hardness, temperature, color, etc., alter

the biological availability or toxicity of a pollutant; or

ii.

The sensitivity of the aquatic organisms species that “occur at the site” differs from the

species actually tested in developing the criteria. The phrase “occur at the site” includes

the species, genera, families, orders, classes, and phyla that: are usually present at the

site; are present at the site only seasonally due to migration; are present intermittently

40 CFR Appendix-F-to-Part-132 “” 1.b.ii. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “” 1.c.

because they periodically return to or extend their ranges into the site; were present at the

site in the past, are not currently present at the site due to degraded conditions, and are

expected to return to the site when conditions improve; are present in nearby bodies of

water, are not currently present at the site due to degraded conditions, and are expected to

be present at the site when conditions improve. The taxa that “occur at the site” cannot be

determined merely by sampling downstream and/or upstream of the site at one point in

time. “Occur at the site” does not include taxa that were once present at the site but

cannot exist at the site now due to permanent physical alteration of the habitat at the site

resulting, for example, from dams, etc.

Less stringent modifications also may be developed to acute and chronic aquatic life criteria or

values to reflect local physical and hydrological conditions.

Guidance on developing site-specific criteria is provided in Chapter 3 of the U.S. EPA Water

Quality Standards Handbook, Second Edition—Revised (1994).

Any modifications to protect threatened or endangered aquatic species required by procedure

1.A of this appendix may be accomplished using either of the two following procedures:

If the Species Mean Acute Value (SMAV) for a listed or proposed species, or for a

surrogate of such species, is lower than the calculated Final Acute Value (FAV), such lower

SMAV may be used instead of the calculated FAV in developing site-specific modified

criteria; or,

ii.

The site-specific criteria may be calculated using the recalculation procedure for sitespecific modifications described in Chapter 3 of the U.S. EPA Water Quality Standards

Handbook, Second Edition—Revised (1994).

Wildlife.

Wildlife water quality criteria may be modified on a site-specific basis to provide an additional

level of protection, pursuant to authority reserved to the States and Tribes under CWA section

510.

Less stringent site-specific modifications to wildlife water quality criteria may be developed

when a site-specific bioaccumulation factor (BAF) is derived which is lower than the systemwide BAF derived under appendix B of this part. The modification must consider both the

mobility of prey organisms and wildlife populations in defining the site for which criteria are

developed. In addition, there must be a showing that:

Any increased uptake of the toxicant by prey species utilizing the site will not cause

adverse effects in wildlife populations; and

ii.

Wildlife populations utilizing the site or downstream waters will continue to be fully

protected.

Any modification to protect endangered or threatened wildlife species required by procedure

1.A of this appendix must consider both the mobility of prey organisms and wildlife populations

in defining the site for which criteria are developed, and may be accomplished by using the

following recommended method.

40 CFR Appendix-F-to-Part-132 “” 2.c. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “” 2.c.i.

The methodology presented in appendix D to part 132 is used, substituting appropriate

species-specific toxicological, epidemiological, or exposure information, including

changes to the BAF;

ii.

An interspecies uncertainty factor of 1 should be used where epidemiological data are

available for the species in question. If necessary, species-specific exposure parameters

can be derived as presented in appendix D of this part;

iii.

An intraspecies uncertainty factor (to account for protection of individuals within a wildlife

population) should be applied in the denominator of the effect part of the wildlife equation

in appendix D of this part in a manner consistent with the other uncertainty factors

described in appendix D of this part; and

iv.

The resulting wildlife value for the species in question should be compared to the two

class-specific wildlife values which were previously calculated, and the lowest of the three

shall be selected as the site-specific modification.

Note: Further discussion on the use of this methodology may be found in the Great Lakes Water

Quality Initiative Technical Support Document for Wildlife Criteria.

BAFs.

BAFs may be modified on a site-specific basis to larger values, pursuant to the authority

reserved to the States and Tribes under CWA section 510, where reliable data show that local

bioaccumulation is greater than the system-wide value.

BAFs may be modified on a site-specific basis to lower values, where scientifically defensible, if:

The fraction of the total chemical that is freely dissolved in the ambient water is different

than that used to derive the system-wide BAFs (i.e., the concentrations of particulate

organic carbon and the dissolved organic carbon are different than those used to derive

the system-wide BAFs);

ii.

Input parameters of the Gobas model, such as the structure of the aquatic food web and

the disequilibrium constant, are different at the site than those used to derive the systemwide BAFs;

iii.

The percent lipid of aquatic organisms that are consumed and occur at the site is different

than that used to derive the system-wide BAFs; or

iv.

Site-specific field-measured BAFs or biota-sediment accumulation factor (BSAFs) are

determined.

If site-specific BAFs are derived, they shall be derived using the methodology in appendix

B of this part.

Any more stringent modifications to protect threatened or endangered species required by

procedure 1.A of this appendix shall be derived using procedures set forth in the methodology

in appendix B of this part.

Human Health.

40 CFR Appendix-F-to-Part-132 “” 4. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “” 4.a.

Human health criteria or values may be modified on a site-specific basis to provide an

additional level of protection, pursuant to authority reserved to the States and Tribes under

CWA section 510. Human health criteria or values shall be modified on a site-specific basis to

provide additional protection appropriate for highly exposed subpopulations.

Less stringent site-specific modifications to human health criteria or values may be developed

when:

local fish consumption rates are lower than the rate used in deriving human health criteria

or values under appendix C of this part; and/or

ii.

a site-specific BAF is derived which is lower than that used in deriving human health

criteria or values under appendix C of this part.

Notification Requirements. When a State proposes a site-specific modification to a

criterion or value as allowed in section 4.A above, the State should notify the other

Great Lakes States of such a proposal and, for less stringent criteria, supply

appropriate justification.

References.

U.S. EPA. 1984. Water Quality Standards Handbook—Revised. Chapter 3 and

Appendices. U.S. Environmental Protection Agency, Office of Water Resource Center

(RC–4100), 1200 Pennsylvania Ave., NW., Washington, DC 20960.

Procedure 2: Variances from Water Quality Standards for Point Sources

The Great Lakes States or Tribes may adopt water quality standards (WQS) variance procedures and may grant

WQS variances for point sources pursuant to such procedures. Variance procedures shall be consistent with (as

protective as) the provisions in this procedure.

Applicability. A State or Tribe may grant a variance to a WQS which is the basis of a water

quality-based effluent limitation included in a National Pollutant Discharge Elimination

System (NPDES) permit. A WQS variance applies only to the permittee requesting the

variance and only to the pollutant or pollutants specified in the variance. A variance does

not affect, or require the State or Tribe to modify, the corresponding water quality standard

for the waterbody as a whole.

This provision shall not apply to new Great Lakes dischargers or recommencing dischargers.

A variance to a water quality standard shall not be granted that would likely jeopardize the continued

existence of any endangered or threatened species listed under Section 4 of the Endangered Species Act

(ESA) or result in the destruction or adverse modification of such species' critical habitat.

A WQS variance shall not be granted if standards will be attained by implementing effluent limits required

under sections 301(b) and 306 of the Clean Water Act (CWA) and by the permittee implementing costeffective and reasonable best management practices for nonpoint source control.

Maximum Timeframe for Variances. A WQS variance shall not exceed five years or the term of the

NPDES permit, whichever is less. A State or Tribe shall review, and modify as necessary, WQS

variances as part of each water quality standards review pursuant to section 303(c) of the CWA.

40 CFR Appendix-F-to-Part-132 3.B. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

Conditions to Grant a Variance. A variance may be granted if:

40 CFR Appendix-F-to-Part-132 3.C.

The permittee demonstrates to the State or Tribe that attaining the WQS is not feasible

because:

Naturally occurring pollutant concentrations prevent the attainment of the WQS;

Natural, ephemeral, intermittent or low flow conditions or water levels prevent the

attainment of the WQS, unless these conditions may be compensated for by the discharge

of sufficient volume of effluent to enable WQS to be met without violating State or Tribal

water conservation requirements;

Human-caused conditions or sources of pollution prevent the attainment of the WQS and

cannot be remedied, or would cause more environmental damage to correct than to leave

in place;

Dams, diversions or other types of hydrologic modifications preclude the attainment of the

WQS, and it is not feasible to restore the waterbody to its original condition or to operate

such modification in a way that would result in the attainment of the WQS;

Physical conditions related to the natural features of the waterbody, such as the lack of a

proper substrate cover, flow, depth, pools, riffles, and the like, unrelated to chemical water

quality, preclude attainment of WQS; or

Controls more stringent than those required by sections 301(b) and 306 of the CWA would

result in substantial and widespread economic and social impact.

In addition to the requirements of C.1, above, the permittee shall also:

Show that the variance requested conforms to the requirements of the State's or Tribe's

antidegradation procedures; and

Characterize the extent of any increased risk to human health and the environment

associated with granting the variance compared with compliance with WQS absent the

variance, such that the State or Tribe is able to conclude that any such increased risk is

consistent with the protection of the public health, safety and welfare.

Submittal of Variance Application. The permittee shall submit an application for a variance to the

regulatory authority issuing the permit. The application shall include:

All relevant information demonstrating that attaining the WQS is not feasible based on one or

more of the conditions in section C.1 of this procedure; and,

All relevant information demonstrating compliance with the conditions in section C.2 of this

procedure.

Public Notice of Preliminary Decision. Upon receipt of a complete application for a variance, and

upon making a preliminary decision regarding the variance, the State or Tribe shall public notice the

request and preliminary decision for public comment pursuant to the regulatory authority's

Administrative Procedures Act and shall notify the other Great Lakes States and Tribes of the

preliminary decision. This public notice requirement may be satisfied by including the supporting

information for the variance and the preliminary decision in the public notice of a draft NPDES

permit.

40 CFR Appendix-F-to-Part-132 3.E. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 3.F.

Final Decision on Variance Request. The State or Tribe shall issue a final decision on the variance

request within 90 days of the expiration of the public comment period required in section E of this

procedure. If all or part of the variance is approved by the State or Tribe, the decision shall include all

permit conditions needed to implement those parts of the variance so approved. Such permit

conditions shall, at a minimum, require:

Compliance with an initial effluent limitation which, at the time the variance is granted,

represents the level currently achievable by the permittee, and which is no less stringent than

that achieved under the previous permit;

That reasonable progress be made toward attaining the water quality standards for the

waterbody as a whole through appropriate conditions;

When the duration of a variance is shorter than the duration of a permit, compliance with an

effluent limitation sufficient to meet the underlying water quality standard, upon the expiration

of said variance; and

A provision that allows the permitting authority to reopen and modify the permit based on any

State or Tribal triennial water quality standards revisions to the variance.

The State shall deny a variance request if the permittee fails to make the demonstrations

required under section C of this procedure.

Incorporating Variance into Permit. The State or Tribe shall establish and incorporate into the

permittee's NPDES permit all conditions needed to implement the variance as determined in section

F of this procedure.

Renewal of Variance. A variance may be renewed, subject to the requirements of sections A through

G of this procedure. As part of any renewal application, the permittee shall again demonstrate that

attaining WQS is not feasible based on the requirements of section C of this procedure. The

permittee's application shall also contain information concerning its compliance with the conditions

incorporated into its permit as part of the original variance pursuant to sections F and G of this

procedure. Renewal of a variance may be denied if the permittee did not comply with the conditions

of the original variance.

EPA Approval. All variances and supporting information shall be submitted by the State or Tribe to

the appropriate EPA regional office and shall include:

Relevant permittee applications pursuant to section D of this procedure;

Public comments and records of any public hearings pursuant to section E of this procedure;

The final decision pursuant to section F of this procedure; and,

NPDES permits issued pursuant to section G of this procedure.

Items required by sections I.1 through I.3. of this procedure shall be submitted by the State

within 30 days of the date of the final variance decision. The item required by section I.4 of this

procedure shall be submitted in accordance with the State or Tribe Memorandum of Agreement

with the Regional Administrator pursuant to 40 CFR 123.24.

EPA shall review the State or Tribe submittal for compliance with the CWA pursuant to 40 CFR

123.44, and 40 CFR 131.21.

State WQS Revisions. All variances shall be appended to the State or Tribe WQS rules.

40 CFR Appendix-F-to-Part-132 3.J. (enhanced display)

page 6 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 A.

Procedure 3: Total Maximum Daily Loads, Wasteload Allocations for Point Sources, Load

Allocations for Nonpoint Sources, Wasteload Allocations in the Absence of a TMDL, and

Preliminary Wasteload Allocations for Purposes of Determining the Need for Water

Quality Based Effluent Limits

The Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this procedure 3 for the

purpose of developing Total Maximum Daily Loads (TMDLs), Wasteload Allocations (WLAs) in the Absence of

TMDLs, and Preliminary Wasteload Allocations for Purposes of Determining the Need for Water Quality Based

Effluent Limits (WQBELs), except as specifically provided.

Where a State or Tribe develops an assessment and remediation plan that the State or Tribe certifies

meets the requirements of sections B through F of this procedure and public participation

requirements applicable to TMDLs, and that has been approved by EPA as meeting those

requirements under 40 CFR 130.6, the assessment and remediation plan may be used in lieu of a

TMDL for purposes of appendix F to part 132. Assessment and remediation plans under this

procedure may include, but are not limited to, Lakewide Management Plans, Remedial Action Plans,

and State Water Quality Management Plans. Also, any part of an assessment and remediation plan

that also satisfies one or more requirements under Clean Water Act (CWA) section 303(d) or

implementing regulations may be incorporated by reference into a TMDL as appropriate.

Assessment and remediation plans under this section should be tailored to the level of detail and

magnitude for the watershed and pollutant being assessed.

General Conditions of Application. Except as provided in § 132.4, the following are conditions

applicable to establishing TMDLs for all pollutants and pollutant parameters in the Great Lakes

System, with the exception of whole effluent toxicity, unless otherwise provided in procedure 6 of

appendix F. Where specified, these conditions also apply to wasteload allocations (WLAs) calculated

in the absence of TMDLs and to preliminary WLAs for purposes of determining the needs for

WQBELs under procedure 5 of appendix F.

TMDLs Required. TMDLs shall, at a minimum, be established in accordance with the listing and priority

setting process established in section 303(d) of the CWA and at 40 CFR 130.7. Where water quality

standards cannot be attained immediately, TMDLs must reflect reasonable assurances that water quality

standards will be attained in a reasonable period of time. Some TMDLs may be based on attaining water

quality standards over a period of time, with specific controls on individual sources being implemented in

stages. Determining the reasonable period of time in which water quality standards will be met is a casespecific determination considering a number of factors including, but not limited to: receiving water

characteristics; persistence, behavior and ubiquity of pollutants of concern; type of remediation activities

necessary; available regulatory and non-regulatory controls; and individual State or Tribal requirements for

attainment of water quality standards.

Attainment of Water Quality Standards. A TMDL must ensure attainment of applicable water quality

standards, including all numeric and narrative criteria, Tier I criteria, and Tier II values for each pollutant or

pollutants for which a TMDL is established.

TMDL Allocations.

40 CFR Appendix-F-to-Part-132 3. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 3.a.

TMDLs shall include WLAs for point sources and load allocations (LAs) for nonpoint sources,

including natural background, such that the sum of these allocations is not greater than the loading

capacity of the water for the pollutant(s) addressed by the TMDL, minus the sum of a specified

margin of safety (MOS) and any capacity reserved for future growth.

Nonpoint source LAs shall be based on:

Existing pollutant loadings if changes in loadings are not reasonably anticipated to occur;

ii.

Increases in pollutant loadings that are reasonably anticipated to occur;

iii.

Anticipated decreases in pollutant loadings if such decreased loadings are technically feasible

and are reasonably anticipated to occur within a reasonable time period as a result of

implementation of best management practices or other load reduction measures. In

determining whether anticipated decreases in pollutant loadings are technically feasible and

can reasonably be expected to occur within a reasonable period of time, technical and

institutional factors shall be considered. These decisions are case-specific and should reflect

the particular TMDL under consideration.

WLAs. The portion of the loading capacity not assigned to nonpoint sources including background,

or to an MOS, or reserved for future growth is allocated to point sources. Upon reissuance, NPDES

permits for these point sources must include effluent limitations consistent with WLAs in EPAapproved or EPA-established TMDLs.

Monitoring. For LAs established on the basis of subsection b.iii above, monitoring data shall be

collected and analyzed in order to validate the TMDL's assumptions, to varify anticipated load

reductions, to evaluate the effectiveness of controls being used to implement the TMDL, and to

revise the WLAs and LAs as necessary to ensure that water quality standards will be achieved within

the time-period established in the TMDL.

WLA Values. If separate EPA-approved or EPA-established TMDLs are prepared for different segments of

the same watershed, and the separate TMDLs each include WLAs for the same pollutant for one or more

of the same point sources, then WQBELs for that pollutant for the point source(s) shall be consistent with

the most stringent of those WLAs in order to ensure attainment of all applicable water quality standards.

Margin of Safety (MOS). Each TMDL shall include a MOS sufficient to account for technical uncertainties

in establishing the TMDL and shall describe the manner in which the MOS is determined and incorporated

into the TMDL. The MOS may be provided by leaving a portion of the loading capacity unallocated or by

using conservative modeling assumptions to establish WLAs and LAs. If a portion of the loading capacity

is left unallocated to provide a MOS, the amount left unallocated shall be described. If conservative

modeling assumptions are relied on to provide a MOS, the specific assumptions providing the MOS shall

be identified.

More Stringent Requirements. States and Tribes may exercise authority reserved to them under section

510 of the CWA to develop more stringent TMDLs (including WLAs and LAs) than are required herein,

provided that all LAs in such TMDLs reflect actual nonpoint source loads or those loads that can

reasonably be expected to occur within a reasonable time-period as a result of implementing nonpoint

source controls.

40 CFR Appendix-F-to-Part-132 6. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 7.

Accumulation in Sediments. TMDLs shall reflect, where appropriate and where sufficient data are

available, contributions to the water column from sediments inside and outside of any applicable mixing

zones. TMDLs shall be sufficiently stringent so as to prevent accumulation of the pollutant of concern in

sediments to levels injurious to designated or existing uses, human health, wildlife and aquatic life.

Wet Weather Events. Notwithstanding the exception provided for the establishment of controls on wet

weather point sources in § 132.4(e)(1), TMDLs shall reflect, where appropriate and where sufficient data

are available, discharges resulting from wet weather events. This procedure does not provide specific

procedures for considering discharges resulting from wet weather events. However, some of the

provisions of procedure 3 may be deemed appropriate for considering wet weather events on a case-bycase basis.

Background Concentration of Pollutants. The representative background concentration of pollutants shall

be established in accordance with this subsection to develop TMDLs, WLAs calculated in the absence of

a TMDL, or preliminary WLAs for purposes of determining the need for WQBELs under procedure 5 of

appendix F. Background loadings may be accounted for in a TMDL through an allocation to a single

“background” category or through individual allocations to the various background sources.

Definition of Background. “Background” represents all loadings that:

(1) flow from upstream waters into the specified watershed, waterbody or waterbody segment for

which a TMDL, WLA in the absence of a TMDL or preliminary WLA for the purpose of

determining the need for a WQBEL is being developed;

(2) enter the specified watershed, waterbody or waterbody segment through atmospheric

deposition or sediment release or resuspension; or

(3) occur within the watershed, waterbody or waterbody segment as a result of chemical reactions.

Data considerations. When determining what available data are acceptable for use in calculating

background, the State or Tribe should use best professional judgment, including consideration of the

sampling location and the reliability of the data through comparison to reported analytical detection

levels and quantification levels. When data in more than one of the data sets or categories described

in section B.9.c.i through B.9.c.iii below exist, best professional judgment should be used to select

the one data set that most accurately reflects or estimates background concentrations. Pollutant

degradation and transport information may be considered when utilizing pollutant loading data.

Calculation requirements. Except as provided below, the representative background concentration for

a pollutant in the specified watershed, waterbody or waterbody segment shall be established on a

case-by-case basis as the geometric mean of:

Acceptable available water column data; or

ii.

Water column concentrations estimated through use of acceptable available caged or resident

fish tissue data; or

iii.

Water column concentrations estimated through use of acceptable available or projected

pollutant loading data.

Detection considerations.

Commonly accepted statistical techniques shall be used to evaluate data sets consisting of

values both above and below the detection level.

40 CFR Appendix-F-to-Part-132 9.d.i. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

ii.

40 CFR Appendix-F-to-Part-132 9.d.ii.

When all of the acceptable available data in a data set or category, such as water column,

caged or resident fish tissue or pollutant loading data, are below the level of detection for a

pollutant, then all the data for that pollutant in that data set shall be assumed to be zero.

10. Effluent Flow. If WLAs are expressed as concentrations of pollutants, the TMDL shall also indicate the

point source effluent flows assumed in the analyses. Mass loading limitations established in NPDES

permits must be consistent with both the WLA and assumed effluent flows used in establishing the

TMDL.

11. Reserved Allocations. TMDLs may include reserved allocations of loading capacity to accommodate

future growth and additional sources. Where such reserved allocations are not included in a TMDL, any

increased loadings of the pollutant for which the TMDL was developed that are due to a new or expanded

discharge shall not be allowed unless the TMDL is revised in accordance with these proceudres to include

an allocation for the new or expanded discharge.

C. Mixing Zones for Bioaccumulative Chemicals of Concern (BCCs). The following requirements shall be

applied in establishing TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs for purposes of

determining the need for WQBELs under procedure 5 of appendix F, for BCCs:

There shall be no mixing zones available for new discharges of BCCs to the Great Lakes System. WLAs

established through TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs for purposes of

determining the need for WQBELs for new discharges of BCCs shall be set no higher than the most

stringent applicable water quality criteria or values for the BCCs in question. This prohibition takes effect

for a Great Lakes State or Tribe on the date EPA approves the State's or Tribe's submission of such

prohibition or publishes a notice under 40 CFR 132.5(f) identifying that prohibition as applying to

discharges within the State or Federal Tribal reservation.

For purposes of section C of procedure 3 of appendix F, new discharges are defined as:

(1) A “discharge of pollutants” (as defined in 40 CFR 122.2) to the Great Lakes System from a building,

structure, facility, or installation, the construction of which commences after the date the prohibition

in section C.1 takes effect in that State or Tribe;

(2) a new discharge from an existing Great Lakes discharger that commences after the date the

prohibition in section C.1 takes effect in that State or Tribe; or

(3) an expanded discharge from an existing Great Lakes discharger that commences after the date the

prohibition in section C.1 takes effect in that State or Tribe, except for those expanded discharges

resulting from changes in loadings of any BCC within the existing capacity and processes (e.g.,

normal operational variability, changes in intake water pollutants, increasing the production hours of

the facility or adding additional shifts, or increasing the rate of production), and that are covered by

the existing applicable control document. Not included within the definition of “new discharge” are

new or expanded discharges of BCCs from a publicly owned treatment works (POTW as defined at

40 CFR 122.2) when such discharges are necessary to prevent a public health threat to the

community (e.g., a situation where a community with failing septic systems is connected to a POTW

to avert a potential public health threat from these failing systems). These and all other discharges

of BCCs are defined as existing discharges.

Up until November 15, 2010, mixing zones for BCCs may be allowed for existing discharges to the Great

Lakes System pursuant to the procedures specified in sections D and E of this procedure.

40 CFR Appendix-F-to-Part-132 3. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 4.

Except as provided in sections C.5 and C.6 of this procedure, permits issued on or after this provision

takes effect in a Great Lakes State or Tribe shall not authorize mixing zones for existing discharges of

BCCs to the Great Lakes System after November 15, 2010. After November 15, 2010, WLAs established

through TMDLs, WLAs established in the absence of TMDLs, and preliminary WLAs for purposes of

determining the need for WQBELs under procedure 5 of appendix F for existing discharges of BCCs to the

Great Lakes System shall be equal to the most stringent applicable water quality criteria or values for the

BCCs in question.

Exception for Water Conservation. Great Lakes States and Tribes may grant mixing zones for any existing

discharge of BCCs to the Great Lakes System beyond the date specified in section C.4 of this procedure

where it can be demonstrated, on a case-by-case basis, that failure to grant a mixing zone would preclude

water conservation measures that would lead to overall load reductions in BCCs, even though higher

concentrations of BCCs occur in the effluent. Such mixing zones must also be consistent with sections D

and E of this procedure.

Exception for Technical and Economic Considerations. Great Lakes States and Tribes may grant mixing

zones beyond the date specified in section C.4 of this procedure for any existing discharge of a BCC to

the Great Lakes System upon the request of a discharger, subject to sections C.6.a through C.6.c below.

The State or Tribe must determine that:

The discharger is in compliance with and will continue to implement, for the BCC in question, all

applicable requirements of Clean Water Act sections 118, 301, 302, 303, 304, 306, 307, 401, and

402, including existing National Pollutant Discharge Elimination System (NPDES) water-quality

based effluent limitations; and

ii.

The discharger has reduced and will continue to reduce the loading of the BCC for which a

mixing zone is requested to the maximum extent possible, such that any additional controls or

pollution prevention measures to reduce or ultimately eliminate the BCC discharge would result

in unreasonable economic effects on the discharger or the affected community because the

controls or measures are not feasible or cost-effective.

Any mixing zone established pursuant to this section shall:

Not result in any less stringent limitations than those existing prior to November 13, 2000;

ii.

Be no larger than necessary to account for the technical constraints and economic effects

identified pursuant to paragraph C.6.a.ii above;

iii.

Meet all applicable acute and chronic aquatic life, wildlife and human health criteria and values

within and at the edge of the mixing zone or be consistent with the applicable TMDL or

assessment and remediation plan authorized under procedure 3.A.

iv.

Be accompanied, as appropriate, by a permit condition requiring the discharger to implement an

ambient monitoring plan to ensure compliance with water quality standards and consistency

with any applicable TMDL or such other strategy consistent with Section A of this procedure,

including the evaluation of alternative means for reducing the BCC from other sources in the

watershed; and

Be limited to one permit term unless the permitting authority makes a new determination in

accordance with this section for each successive permit application in which a mixing zone for

the BCC is sought.

40 CFR Appendix-F-to-Part-132 6.b.v. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 6.c.

For each draft NPDES permit that would allow a mixing zone for one or more BCCs after November

15, 2010, the fact sheet or statement of basis for the draft permit that is required to be made

available through public notice under 40 CFR 124.6(e) shall:

Specify the mixing provisions used in calculating the permit limits; and

ii.

Identify each BCC for which a mixing zone is proposed.

Any mixing zone authorized under sections C.3, C.5 or C.6 must be consistent with sections D and E of

this procedure, as applicable.

D. Deriving TMDLs, WLAs, and LAs for Point and Nonpoint Sources: WLAs in the Absence of a TMDL; and Preliminary

WLAs for Purposes of Determining the Need for WQBELs for OWGL. This section addresses conditions for deriving

TMDLs for Open Waters of the Great Lakes (OWGL), inland lakes and other waters of the Great Lakes System with

no appreciable flow relative to their volumes. State and Tribal procedures to derive TMDLs under this section must

be consistent with (as protective as) the general conditions in section B of this procedure, CWA section 303(d),

existing regulations (40 CFR 130.7), section C of this procedure, and sections D.1. through D.4 below. State and

Tribal procedures to derive WLAs calculated in the absence of a TMDL and preliminary WLAs for purposes of

determining the need for WQBELs under procedure 5 of appendix F must be consistent with sections B.9, C.1, C3

through C.6, and D. 1 through D.4 of this procedure.

Individual point source WLAs and preliminary WLAs for purposes of determining the need for WQBELs

under procedure 5 of appendix F shall assume no greater dilution than one part effluent to 10 parts

receiving water for implementation of numeric and narrative chronic criteria and values (including, but not

limited to human cancer criteria, human cancer values, human noncancer values, human noncancer

criteria, wildlife criteria, and chronic aquatic life criteria and values) unless an alternative mixing zone is

demonstrated as appropriate in a mixing zone demonstration conducted pursuant to section F of this

procedure. In no case shall a mixing zone be granted that exceeds the area where discharge-induced

mixing occurs.

Appropriate mixing zone assumptions to be used in calculating load allocations for nonpoint sources shall

be determined, consistent with applicable State or Tribal requirements, on a case-by-case basis.

WLAs and preliminary WLAs based on acute aquatic life criteria or values shall not exceed the Final Acute

Value (FAV), unless a mixing zone demonstration is conducted and approved pursuant to section F of this

procedure. If mixing zones from two or more proximate sources interact or overlap, the combined effect

must be evaluated to ensure that applicable criteria and values will be met in the area where acute mixing

zones overlap.

In no case shall a mixing zone be granted that would likely jeopardize the continued existence of any

endangered or threatened species listed under section 4 of the ESA or result in the destruction or adverse

modification of such species' critical habitat.

E. Deriving TMDLs, WLAs, and LAs for Point and Nonpoint Sources; WLAs in the Absence of a TMDL; and Preliminary

WLAs for the Purposes of Determining the Need for WQBELs for Great Lakes Systems Tributaries and Connecting

Channels. This section describes conditions for deriving TMDLs for tributaries and connecting channels of the Great

Lakes System that exhibit appreciable flows relative to their volumes. State and Tribal procedures to derive TMDLs

must be consistent with the general conditions listed in section B of this procedure, section C of this procedure,

existing TMDL regulations (40 CFR 130.7) and specific conditions E.1 through E.5. State and Tribal procedures to

40 CFR Appendix-F-to-Part-132 4. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 1.

derive WLAs calculated in the absence of a TMDL, and preliminary WLAs for purposes of determining reasonable

potential under procedure 5 of this appendix for discharges to tributaries and connecting channels must be

consistent with sections B.9, C.1, C.3 through C.6, and E.1 through E.5 of this procedure.

Stream Design. These design flows must be used unless data exist to demonstrate that an alternative

stream design flow is appropriate for stream-specific and pollutant-specific conditions. For purposes of

calculating a TMDL, WLAs in the absence of a TMDL, or preliminary WLAs for the purposes of determining

reasonable potential under procedure 5 of this appendix, using a steady-state model, the stream design

flows shall be:

The 7-day, 10-year stream design flow (7Q10), or the 4-day, 3-year biologically-based stream design

flow for chronic aquatic life criteria or values;

The 1-day, 10-year stream design flow (1Q10), for acute aquatic life criteria or values;

The harmonic mean flow for human health criteria or values;

The 90-day, 10-year flow (90Q10) for wildlife criteria.

TMDLs, WLAs in the absence of TMDLs, and preliminary WLAs for the purpose of determining the

need for WQBELs calculated using dynamic modelling do not need to incorporate the stream design

flows specified in sections E.1.a through E.1.d of this procedure.

Loading Capacity. The loading capacity is the greatest amount of loading that a water can receive without

violating water quality standards. The loading capacity is initially calculated at the farthest downstream

location in the watershed drainage basin. The maximum allowable loading consistent with the attainment

of each applicable numeric criterion or value for a given pollutant is determined by multiplying the

applicable criterion or value by the flow at the farthest downstream location in the tributary basin at the

design flow condition described above. This loading is then compared to the loadings at sites within the

basin to assure that applicable numeric criteria or values for a given pollutant are not exceeded at all

applicable sites. The lowest load is then selected as the loading capacity.

Polluant Degradation. TMDLs, WLAs in the absence of a TMDL and preliminary WLAs for purposes of

determining the need for WQBELs under procedure 5 of appendix F shall be based on the assumption that

a pollutant does not degrade. However, the regulatory authority may take into account degradation of the

pollutant if each of the following conditions are met.

Scientifically valid field studies or other relevant information demonstrate that degradation of the

pollutant is expected to occur under the full range of environmental conditions expected to be

encountered;

Scientifically valid field studies or other relevant information address other factors that affect the

level of pollutants in the water column including, but not limited to, resuspension of sediments,

chemical speciation, and biological and chemical transformation.

Acute Aquatic Life Criteria and Values. WLAs and LAs established in a TMDL, WLAs in the absence of a

TMDL, and preliminary WLAs for the purpose of determining the need for WQBELs based on acute aquatic

life criteria or values shall not exceed the FAV, unless a mixing zone demonstration is completed and

approved pursuant to section F of this procedure. If mixing zones from two or more proximate sources

interact or overlap, the combined effect must be evaluated to ensure that applicable criteria and values

will be met in the area where any applicable acute mixing zones overlap. This acute WLA review shall

include, but not be limited to, consideration of:

40 CFR Appendix-F-to-Part-132 4. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 4.a.

The expected dilution under all effluent flow and concentration conditions at stream design flow;

Maintenance of a zone of passage for aquatic organisms; and

Protection of critical aquatic habitat.

In no case shall a permitting authority grant a mixing zone that would likely jeopardize the continued existence of

any endangered or threatened species listed under section 4 of the ESA or result in the destruction or adverse

modification of such species' critical habitat.

Chronic Mixing Zones. WLAs and LAs established in a TMDL, WLAs in the absence of a TMDL, and

preliminary WLAs for the purposes of determining the need for WQBELs for protection of aquatic life,

wildlife and human health from chronic effects shall be calculated using a dilution fraction no greater than

25 percent of the stream design flow unless a mixing zone demonstration pursuant to section F of this

procedure is conducted and approved. A demonstration for a larger mixing zone may be provided, if

approved and implemented in accordance with section F of this procedure. In no case shall a permitting

authority grant a mixing zone that would likely jeopardize the continued existence of any endangered or

threatened species listed under section 4 of the ESA or result in the destruction or adverse modification

of such species' critical habitat.

F. Mixing Zone Demonstration Requirements.

For purposes of establishing a mixing zone other than as specified in sections D and E above, a mixing

zone demonstration must:

Describe the amount of dilution occurring at the boundaries of the proposed mixing zone and the

size, shape, and location of the area of mixing, including the manner in which diffusion and

dispersion occur;

For sources discharging to the open waters of the Great Lakes (OWGLs), define the location at which

discharge-induced mixing ceases;

Document the substrate character and geomorphology within the mixing zone;

Show that the mixing zone does not interfere with or block passage of fish or aquatic life;

Show that the mixing zone will be allowed only to the extent that the level of the pollutant permitted

in the waterbody would not likely jeopardize the continued existence of any endangered or

threatened species listed under section 4 of the ESA or result in the destruction or adverse

modification of such species' critical habitat;

Show that the mixing zone does not extend to drinking water intakes;

Show that the mixing zone would not otherwise interfere with the designated or existing uses of the

receiving water or downstream waters;

Document background water quality concentrations;

Show that the mixing zone does not promote undesirable aquatic life or result in a dominance of

nuisance species; and

Provide that by allowing additional mixing/dilution:

40 CFR Appendix-F-to-Part-132 1.j. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 1.j.i.

Substances will not settle to form objectionable deposits;

ii.

Floating debris, oil, scum, and other matter in concentrations that form nuisances will not be

produced; and

iii.

Objectionable color, odor, taste or turbidity will not be produced.

In addition, the mixing zone demonstration shall address the following factors:

Whether or not adjacent mixing zones overlap;

Whether organisms would be attracted to the area of mixing as a result of the effluent character; and

Whether the habitat supports endemic or naturally occurring species.

The mixing zone demonstration must be submitted to EPA for approval. Following approval of a mixing

zone demonstration consistent with sections F.1 and F.2, adjustment to the dilution ratio specified in

section D.1 of this procedure shall be limited to the dilution available in the area where discharger-induced

mixing occurs.

The mixing zone demonstration shall be based on the assumption that a pollutant does not degrade

within the proposed mixing zone, unless:

Scientifically valid field studies or other relevant information demonstrate that degradation of the

pollutant is expected to occur under the full range of environmental conditions expected to be

encountered; and

Scientifically valid field studies or other relevant information address other factors that affect the

level of pollutants in the water column including, but not limited to, resuspension of sediments,

chemical speciation, and biological and chemical transformation.

Procedure 4: Additivity

The Great Lakes States and Tribes shall adopt additivity provisions consistent with (as protective as) this

procedure.

The Great Lakes States and Tribes shall adopt provisions to protect human health from the potential

adverse additive effects from both the noncarcinogenic and carcinogenic components of chemical

mixtures in effluents. For the chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs)

listed in Table 1, potential adverse additive effects in effluents shall be accounted for in accordance with

section B of this procedure.

Toxicity Equivalency Factors (TEFs)/Bioaccumulation Equivalency Factors (BEFs).

The TEFs in Table 1 and BEFs in Table 2 shall be used when calculating a 2,3,7,8-TCDD toxicity

equivalence concentration in effluent to be used when implementing both human health noncancer

and cancer criteria. The chemical concentration of each CDDs and CDFs in effluent shall be

converted to a 2,3,7,8-TCDD toxicity equivalence concentration in effluent by

(a) multiplying the chemical concentration of each CDDs and CDFs in the effluent by the

appropriate TEF in Table 1 below,

40 CFR Appendix-F-to-Part-132 B.1.(a) (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 B.1.(b)

(b) multiplying each product from step (a) by the BEF for each CDDs and CDFs in Table 2 below,

and

equivalence concentration in effluent is:

where:

(TEC)tcdd = 2,3,7,8-TCDD toxicity equivalence concentration in effluent

(C)x = concentration of total chemical x in effluent

(TEF)x = TCDD toxicity equivalency factor for x

(BEF)x = TCDD bioaccumulation equivalency factor for x

The 2,3,7,8-TCDD toxicity equivalence concentration in effluent shall be used when developing waste

load allocations under procedure 3, preliminary waste load allocations for purposes of determining

reasonable potential under procedure 5, and for purposes of establishing effluent quality limits under

procedure 5.

40 CFR Appendix-F-to-Part-132 B.2. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 B.2.

Table 1—Toxicity Equivalency Factors for CDDs and CDFs

Congener

TEF

2,3,7,8-TCDD

1.0

1,2,3,7,8-PeCDD

0.5

1,2,3,4,7,8-HxCDD

0.1

1,2,3,6,7,8-HxCDD

0.1

1,2,3,7,8,9-HxCDD

0.1

1,2,3,4,6,7,8-HpCDD

0.01

OCDD

0.001

2,3,7,8-TCDF

0.1

1,2,3,7,8-PeCDF

0.05

2,3,4,7,8-PeCDF

0.5

1,2,3,4,7,8-HxCDF

0.1

1,2,3,6,7,8-HxCDF

0.1

2,3,4,6,7,8-HxCDF

0.1

1,2,3,7,8,9-HxCDF

0.1

1,2,3,4,6,7,8-HpCDF

0.01

1,2,3,4,7,8,9-HpCDF

0.01

OCDF

0.001

Table 2—Bioaccumulation Equivalency Factors for CDDs and CDFs

Congener

BEF

2,3,7,8-TCDD

1.0

1,2,3,7,8-PeCDD

0.9

1,2,3,4,7,8-HxCDD

0.3

1,2,3,6,7,8-HxCDD

0.1

1,2,3,7,8,9-HxCDD

0.1

1,2,3,4,6,7,8-HpCDD

0.05

OCDD

0.01

2,3,7,8-TCDF

0.8

1,2,3,7,8-PeCDF

0.2

2,3,4,7,8-PeCDF

1.6

1,2,3,4,7,8-HxCDF

0.08

1,2,3,6,7,8-HxCDF

0.2

2,3,4,6,7,8-HxCDF

0.7

1,2,3,7,8,9-HxCDF

0.6

1,2,3,4,6,7,8-HpCDF

0.01

1,2,3,4,7,8,9-HpCDF

0.4

OCDF

0.02

40 CFR Appendix-F-to-Part-132 B.2. (enhanced display)

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Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 A.

Procedure 5: Reasonable Potential To Exceed Water Quality Standards

Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this procedure. If a

permitting authority determines that a pollutant is or may be discharged into the Great Lakes System at a level

which will cause, have the reasonable potential to cause, or contribute to an excursion above any Tier I criterion or

Tier II value, the permitting authority shall incorporate a water quality-based effluent limitation (WQBEL) in an

NPDES permit for the discharge of that pollutant. When facility-specific effluent monitoring data are available, the

permitting authority shall make this determination by developing preliminary effluent limitations (PEL) and

comparing those effluent limitations to the projected effluent quality (PEQ) of the discharge in accordance with the

following procedures. In all cases, the permitting authority shall use any valid, relevant, representative information

that indicates a reasonable potential to exceed any Tier I criterion or Tier II value.

Developing Preliminary Effluent Limitations on the Discharge of a Pollutant From a Point Source.

The permitting authority shall develop preliminary wasteload allocations (WLAs) for the discharge of

the pollutant from the point source to protect human health, wildlife, acute aquatic life, and chronic

aquatic life, based upon any existing Tier I criteria. Where there is no Tier I criterion nor sufficient

data to calculate a Tier I criterion, the permitting authority shall calculate a Tier II value for such

pollutant for the protection of human health, and aquatic life and the preliminary WLAs shall be

based upon such values. Where there is insufficient data to calculate a Tier II value, the permitting

authority shall apply the procedure set forth in section C of this procedure to determine whether data

must be generated to calculate a Tier II value.

The following provisions in procedure 3 of appendix F shall be used as the basis for determining

preliminary WLAs in accordance with section 1 of this procedure: procedure 3.B.9, Background

Concentrations of Pollutants; procedure 3.C, Mixing Zones for Bioaccumulative Chemicals of

Concern (BCCs), procedures 3.C.1, and 3.C.3 through 3.C.6; procedure 3.D, Deriving TMDLs for

Discharges to Lakes (when the receiving water is an open water of the Great Lakes (OWGL), an

inland lake or other water of the Great Lakes System with no appreciable flow relative to its volume);

procedure 3.E, Deriving TMDLs, WLAs and Preliminary WLAs, and load allocations (LAs) for

Discharges to Great Lakes System Tributaries (when the receiving water is a tributary or connecting

channel of the Great Lakes that exhibits appreciable flow relative to its volume); and procedure 3.F,

Mixing Zone Demonstration Requirements.

The permitting authority shall develop PELs consistent with the preliminary WLAs developed

pursuant to sections A.1 and A.2 of this procedure, and in accordance with existing State or Tribal

procedures for converting WLAs into WQBELs. At a minimum:

The PELs based upon criteria and values for the protection of human health and wildlife shall be

expressed as monthly limitations;

The PELs based upon criteria and values for the protection of aquatic life from chronic effects

shall be expressed as either monthly limitations or weekly limitations; and

The PELs based upon the criteria and values for the protection of aquatic life from acute effects

shall be expressed as daily limitations.

Determining Reasonable Potential Using Effluent Pollutant Concentration Data.

40 CFR Appendix-F-to-Part-132 B. (enhanced display)

page 18 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 B.1.

If representative, facility-specific effluent monitoring data samples are available for a pollutant discharged

from a point source to the waters of the Great Lakes System, the permitting authority shall apply the

following procedures:

The permitting authority shall specify the PEQ as the 95 percent confidence level of the 95th

percentile based on a log-normal distribution of the effluent concentration; or the maximum

observed effluent concentration, whichever is greater. In calculating the PEQ, the permitting authority

shall identify the number of effluent samples and the coefficient of variation of the effluent data,

obtain the appropriate multiplying factor from Table 1 of procedure 6 of appendix F, and multiply the

maximum effluent concentration by that factor. The coefficient of variation of the effluent data shall

be calculated as the ratio of the standard deviation of the effluent data divided by the arithmetic

average of the effluent data, except that where there are fewer than ten effluent concentration data

points the coefficient of variation shall be specified as 0.6. If the PEQ exceeds any of the PELs

developed in accordance with section A.3 of this procedure, the permitting authority shall establish a

WQBEL in a NPDES permit for such pollutant.

In lieu of following the procedures under section B.1 of this procedure, the permitting authority may

apply procedures consistent with the following:

The permitting authority shall specify the PEQ as the 95th percentile of the distribution of the

projected population of daily values of the facility-specific effluent monitoring data projected

using a scientifically defensible statistical method that accounts for and captures the long-term

daily variability of the effluent quality, accounts for limitations associated with sparse data sets

and, unless otherwise shown by the effluent data set, assumes a lognormal distribution of the

facility-specific effluent data. If the PEQ exceeds the PEL based on the criteria and values for

the protection of aquatic life from acute effects developed in accordance with section A.3 of

this procedure, the permitting authority shall establish a WQBEL in an NPDES permit for such

pollutant;

The permitting authority shall calculate the PEQ as the 95th percentile of the distribution of the

projected population of monthly averages of the facility-specific effluent monitoring data using

a scientifically defensible statistical method that accounts for and captures the long-term

variability of the monthly average effluent quality, accounts for limitations associated with

sparse data sets and, unless otherwise shown by the effluent data set, assumes a lognormal

distribution of the facility-specific effluent data. If the PEQ exceeds the PEL based on criteria

and values for the protection of aquatic life from chronic effects, human health or wildlife

developed in accordance with section A.3 of this procedure, the permitting authority shall

establish a WQBEL in an NPDES permit for such pollutant; and

The permitting authority shall calculate the PEQ as the 95th percentile of the distribution of the

projected population of weekly averages of the facility-specific effluent monitoring data using a

scientifically defensible statistical method that accounts for and captures the long-term

variability of the weekly average effluent quality, accounts for limitations associated with

sparse data sets and, unless otherwise shown by the effluent data set, assumes a lognormal

distribution of the facility-specific effluent data. If the PEQ exceeds the PEL based on criteria

and values to protect aquatic life from chronic effects developed in accordance with section

A.3 of this procedure, the permitting authority shall establish a WQBEL in an NPDES permit for

such pollutant.

Developing Necessary Data to Calculate Tier II Values Where Such Data Does Not Currently Exist.

40 CFR Appendix-F-to-Part-132 C. (enhanced display)

page 19 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 C.1.

Except as provided in sections C.2, C.4, or D of this procedure, for each pollutant listed in Table 6 of

part 132 that a permittee reports as known or believed to be present in its effluent, and for which

pollutant data sufficient to calculate Tier II values for non-cancer human health, acute aquatic life

and chronic aquatic life do not exist, the permitting authority shall take the following actions:

The permitting authority shall use all available, relevant information, including Quantitative

Structure Activity Relationship information and other relevant toxicity information, to estimate

ambient screening values for such pollutant which will protect humans from health effects

other than cancer, and aquatic life from acute and chronic effects.

Using the procedures specified in sections A.1 and A.2 of this procedure, the permitting

authority shall develop preliminary WLAs for the discharge of the pollutant from the point

source to protect human health, acute aquatic life, and chronic aquatic life, based upon the

estimated ambient screening values.

The permitting authority shall develop PELs in accordance with section A.3 of this procedure,

which are consistent with the preliminary WLAs developed in accordance with section C.1.b of

this procedure.

The permitting authority shall compare the PEQ developed according to the procedures set

forth in section B of this procedure to the PELs developed in accordance with section C.1.c of

this procedure. If the PEQ exceeds any of the PELs, the permitting authority shall generate or

require the permittee to generate the data necessary to derive Tier II values for noncancer

human health, acute aquatic life and chronic aquatic life.

The data generated in accordance with section C.1.d of this procedure shall be used in

calculating Tier II values as required under section A.1 of this procedure. The calculated Tier II

value shall be used in calculating the preliminary WLA and PEL under section A of this

procedure, for purposes of determining whether a WQBEL must be included in the permit. If the

permitting authority finds that the PEQ exceeds the calculated PEL, a WQBEL for the pollutant

or a permit limit on an indicator parameter consistent with 40 CFR 122.44(d)(1)(vi)(C) must be

included in the permit.

With the exception of bioaccumulative chemicals of concern (BCCs), a permitting authority is not

required to apply the procedures set forth in section C.1 of this procedure or include WQBELs to

protect aquatic life for any pollutant listed in Table 6 of part 132 discharged by an existing point

source into the Great Lakes System, if:

There is insufficient data to calculate a Tier I criterion or Tier II value for aquatic life for such

pollutant;

The permittee has demonstrated through a biological assessment that there are no acute or

chronic effects on aquatic life in the receiving water; and

The permittee has demonstrated in accordance with procedure 6 of this appendix that the

whole effluent does not exhibit acute or chronic toxicity.

Nothing in sections C.1 or C.2 of this procedure shall preclude or deny the right of a permitting

authority to:

Determine, in the absence of the data necessary to derive a Tier II value, that the discharge of

the pollutant will cause, have the reasonable potential to cause, or contribute to an excursion

above a narrative criterion for water quality; and

40 CFR Appendix-F-to-Part-132 C.3.a. (enhanced display)

page 20 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 C.3.b.

Incorporate a WQBEL for the pollutant into an NPDES permit.

If the permitting authority develops a WQBEL consistent with section C.3 of this procedure, and the

permitting authority demonstrates that the WQBEL developed under section C.3 of this procedure is

at least as stringent as a WQBEL that would have been based upon the Tier II value or values for that

pollutant, the permitting authority shall not be obligated to generate or require the permittee to

generate the data necessary to derive a Tier II value or values for that pollutant.

Consideration of Intake Pollutants in Determining Reasonable Potential.

General.

Any procedures adopted by a State or Tribe for considering intake pollutants in water qualitybased permitting shall be consistent with this section and section E.

The determinations under this section and section E shall be made on a pollutant-by-pollutant,

outfall-by-outfall, basis.

This section and section E apply only in the absence of a TMDL applicable to the discharge

prepared by the State or Tribe and approved by EPA, or prepared by EPA pursuant to 40 CFR

130.7(d), or in the absence of an assessment and remediation plan submitted and approved in

accordance with procedure 3.A. of appendix F. This section and section E do not alter the

permitting authority's obligation under 40 CFR 122.44(d)(vii)(B) to develop effluent limitations

consistent with the assumptions and requirements of any available WLA for the discharge,

which is part of a TMDL prepared by the State or Tribe and approved by EPA pursuant to 40 CFR

130.7, or prepared by EPA pursuant to 40 CFR 130.7(d).

Definition of Same Body of Water.

This definition applies to this section and section E of this procedure.

An intake pollutant is considered to be from the same body of water as the discharge if the

permitting authority finds that the intake pollutant would have reached the vicinity of the outfall

point in the receiving water within a reasonable period had it not been removed by the

permittee. This finding may be deemed established if:

The background concentration of the pollutant in the receiving water (excluding any

amount of the pollutant in the facility's discharge) is similar to that in the intake water;

ii.

There is a direct hydrological connection between the intake and discharge points; and

iii.

Water quality characteristics (e.g., temperature, Ph, hardness) are similar in the intake and

receiving waters.

The permitting authority may also consider other site-specific factors relevant to the transport

and fate of the pollutant to make the finding in a particular case that a pollutant would or would

not have reached the vicinity of the outfall point in the receiving water within a reasonable

period had it not been removed by the permittee.

An intake pollutant from groundwater may be considered to be from the same body of water if

the permitting authority determines that the pollutant would have reached the vicinity of the

outfall point in the receiving water within a reasonable period had it not been removed by the

40 CFR Appendix-F-to-Part-132 D.2.d. (enhanced display)

page 21 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 D.2.e.

permittee, except that such a pollutant is not from the same body of water if the groundwater

contains the pollutant partially or entirely due to human activity, such as industrial, commercial,

or municipal operations, disposed actions, or treatment processes.

An intake pollutant is the amount of a pollutant that is present in waters of the United States

(including groundwater as provided in section D.2.d of this procedure) at the time it is

withdrawn from such waters by the discharger or other facility (e.g., public water supply)

supplying the discharger with intake water.

Reasonable Potential Determination.

The permitting authority may use the procedure described in this section of procedure 5 in lieu

of procedures 5.A through C provided the conditions specified below are met.

The permitting authority may determine that there is no reasonable potential for the discharge

of an identified intake pollutant or pollutant parameter to cause or contribute to an excursion

above a narrative or numeric water quality criterion within an applicable water quality standard

where a discharger demonstrates to the satisfaction of the permitting authority (based upon

information provided in the permit application or other information deemed necessary by the

permitting authority) that:

The facility withdraws 100 percent of the intake water containing the pollutant from the

same body of water into which the discharge is made;

ii.

The facility does not contribute any additional mass of the identified intake pollutant to its

wastewater;

iii.

The facility does not alter the identified intake pollutant chemically or physically in a

manner that would cause adverse water quality impacts to occur that would not occur if

the pollutants were left in-stream;

iv.

The facility does not increase the identified intake pollutant concentration, as defined by

the permitting authority, at the edge of the mixing zone, or at the point of discharge if a

mixing zone is not allowed, as compared to the pollutant concentration in the intake water,

unless the increased concentration does not cause or contribute to an excursion above an

applicable water quality standard; and

The timing and location of the discharge would not cause adverse water quality impacts to

occur that would not occur if the identified intake pollutant were left in-stream.

Upon a finding under section D.3.b of this procedure that a pollutant in the discharge does not

cause, have the reasonable potential to cause, or contribute to an excursion above an

applicable water quality standard, the permitting authority is not required to include a WQBEL

for the identified intake pollutant in the facility's permit, provided:

The NPDES permit fact sheet or statement of basis includes a specific determination that

there is no reasonable potential for the discharge of an identified intake pollutant to cause

or contribute to an excursion above an applicable narrative or numeric water quality

criterion and references appropriate supporting documentation included in the

administrative record;

40 CFR Appendix-F-to-Part-132 D.3.c.i. (enhanced display)

page 22 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 D.3.c.ii.

ii.

The permit requires all influent, effluent, and ambient monitoring necessary to

demonstrate that the conditions in section D.3.b of this procedure are maintained during

the permit term; and

iii.

The permit contains a reopener clause authorizing modification or revocation and

reissuance of the permit if new information indicates changes in the conditions in section

D.3.b of this procedure.

Absent a finding under section D.3.b of this procedure that a pollutant in the discharge does not

cause, have the reasonable potential to cause, or contribute to an excursion above an

applicable water quality standard, the permitting authority shall use the procedures under

sections 5.A through C of this procedure to determine whether a discharge causes, has the

reasonable potential to cause, or contribute to an excursion above an applicable narrative or

numeric water quality criterion.

Consideration of Intake Pollutants in Establishing WQBELs.

General. This section applies only when the concentration of the pollutant of concern upstream of

the discharge (as determined using the provisions in procedure 3.B.9 of appendix F) exceeds the

most stringent applicable water quality criterion for that pollutant.

The requirements of sections D.1–D.2 of this procedure shall also apply to this section.

Intake Pollutants from the Same Body of Water.

In cases where a facility meets the conditions in sections D.3.b.i and D.3.b.iii through D.3.b.v of

this procedure, the permitting authority may establish effluent limitations allowing the facility to

discharge a mass and concentration of the pollutant that are no greater than the mass and

concentration of the pollutant identified in the facility's intake water (“no net addition

limitations”). The permit shall specify how compliance with mass and concentration limitations

shall be assessed. No permit may authorize “no net addition limitations” which are effective

after March 23, 2007. After that date, WQBELs shall be established in accordance with

procedure 5.F.2 of appendix F.

Where proper operation and maintenance of a facility's treatment system results in removal of a

pollutant, the permitting authority may establish limitations that reflect the lower mass and/or

concentration of the pollutant achieved by such treatment, taking into account the feasibility of

establishing such limits.

For pollutants contained in intake water provided by a water system, the concentration of the

intake pollutant shall be determined at the point where the raw water supply is removed from

the same body of water, except that it shall be the point where the water enters the water

supplier's distribution system where the water treatment system removes any of the identified

pollutants from the raw water supply. Mass shall be determined by multiplying the

concentration of the pollutant determined in accordance with this paragraph by the volume of

the facility's intake flow received from the water system.

Intake Pollutants from a Different Body of Water. Where the pollutant in a facility's discharge

originates from a water of the United States that is not the same body of water as the receiving

water (as determined in accordance with section D.2 of this procedure), WQBELs shall be

established based upon the most stringent applicable water quality criterion for that pollutant.

40 CFR Appendix-F-to-Part-132 E.4. (enhanced display)

page 23 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 E.5.

Multiple Sources of Intake Pollutants. Where a facility discharges intake pollutants that originate in

part from the same body of water, and in part from a different body of water, the permitting authority

may apply the procedures of sections E.3 and E.4 of this procedure to derive an effluent limitation

reflecting the flow-weighted average of each source of the pollutant, provided that adequate

monitoring to determine compliance can be established and is included in the permit.

Other Applicable Conditions.

In addition to the above procedures, effluent limitations shall be established to comply with all other

applicable State, Tribal and Federal laws and regulations, including technology-based requirements

and antidegradation policies.

Once the permitting authority has determined in accordance with this procedure that a WQBEL must

be included in an NPDES permit, the permitting authority shall:

Rely upon the WLA established for the point source either as part of any TMDL prepared under

procedure 3 of this appendix and approved by EPA pursuant to 40 CFR 130.7, or as part of an

assessment and remediation plan developed and approved in accordance with procedure 3.A

of this appendix, or, in the absence of such TMDL or plan, calculate WLAs for the protection of

acute and chronic aquatic life, wildlife and human health consistent with the provisions

referenced in section A.1 of this procedure for developing preliminary wasteload allocations,

and

Develop effluent limitations consistent with these WLAs in accordance with existing State or

Tribal procedures for converting WLAs into WQBELs.

When determining whether WQBELs are necessary, information from chemical-specific, whole

effluent toxicity and biological assessments shall be considered independently.

If the geometric mean of a pollutant in fish tissue samples collected from a waterbody exceeds the

tissue basis of a Tier I criterion or Tier II value, after consideration of the variability of the pollutant's

bioconcentration and bioaccumulation in fish, each facility that discharges detectable levels of such

pollutant to that water has the reasonable potential to cause or contribute to an excursion above a

Tier I criteria or a Tier II value and the permitting authority shall establish a WQBEL for such pollutant

in the NPDES permit for such facility.

Procedure 6: Whole Effluent Toxicity Requirements

The Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) procedure 6 of appendix

F of part 132.

The following definitions apply to this part:

Acute toxic unit (TUa ). 100/LC50 where the LC50 is expressed as a percent effluent in the test medium of an

acute whole effluent toxicity (WET) test that is statistically or graphically estimated to be lethal to 50

percent of the test organisms.

Chronic toxic unit (TUc ). 100/NOEC or 100/IC25, where the NOEC and IC25 are expressed as a percent effluent in

the test medium.

40 CFR Appendix-F-to-Part-132 “Chronic toxic unit (TUc” (enhanced display)

page 24 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

40 CFR Appendix-F-to-Part-132 “Inhibition concentration 25

Great Lakes Water Quality Initiative Implementation Procedures

(IC25”

Inhibition concentration 25 (IC25 ). The toxicant concentration that would cause a 25 percent reduction in a nonquantal biological measurement for the test population. For example, the IC25 is the concentration of

toxicant that would cause a 25 percent reduction in mean young per female or in growth for the test

population.

No observed effect concentration (NOEC). The highest concentration of toxicant to which organisms are

exposed in a full life-cycle or partial life-cycle (short-term) test, that causes no observable adverse effects

on the test organisms (i.e., the highest concentration of toxicant in which the values for the observed

responses are not statistically significantly different from the controls).

Whole Effluent Toxicity Requirements. The Great Lakes States and Tribes shall adopt whole effluent

toxicity provisions consistent with the following:

A numeric acute WET criterion of 0.3 acute toxic units (TUa) measured pursuant to test

methods in 40 CFR part 136, or a numeric interpretation of a narrative criterion establishing that

0.3 TUa measured pursuant to test methods in 40 CFR part 136 is necessary to protect aquatic

life from acute effects of WET. At the discretion of the permitting authority, the foregoing

requirement shall not apply in an acute mixing zone that is sized in accordance with EPAapproved State and Tribal methods.

A numeric chronic WET criterion of one chronic toxicity unit (TUc) measured pursuant to test

methods in 40 CFR part 136, or a numeric interpretation of a narrative criterion establishing that

one TUc measured pursuant to test methods in 40 CFR part 136 is necessary to protect aquatic

life from the chronic effects of WET. At the discretion of the permitting authority, the foregoing

requirements shall not apply within a chronic mixing zone consistent with:

(a) procedures 3.D.1 and 3.D.4, for discharges to the open of the Great Lakes (OWGL), inland

lakes and other waters of the Great Lakes System with no appreciable flow relative to their

volume, or

(b) procedure 3.E.5 for discharges to tributaries and connecting channels of the Great Lakes

System.

WET Test Methods. All WET tests performed to implement or ascertain compliance with this

procedure shall be performed in accordance with methods established in 40 CFR part 136.

Permit Conditions.

Where a permitting authority determines pursuant to section D of this procedure that the WET

of an effluent is or may be discharged at a level that will cause, have the reasonable potential to

cause, or contribute to an excursion above any numeric WET criterion or narrative criterion

within a State's or Tribe's water quality standards, the permitting authority:

Shall (except as provided in section C.1.e of this procedure) establish a water qualitybased effluent limitation (WQBEL) or WQBELs for WET consistent with section C.1.b of

this procedure;

Shall calculate WQBELs pursuant to section C.1.a. of this procedure to ensure attainment

of the State's or Tribe's chronic WET criteria under receiving water flow conditions

described in procedures 3.E.1.a (or where applicable, with procedure 3.E.1.e) for Great

Lakes System tributaries and connecting channels, and with mixing zones no larger than

allowed pursuant to section A.2. of this procedure. Shall calculate WQBELs to ensure

attainment of the State's or Tribe's acute WET criteria under receiving water flow

40 CFR Appendix-F-to-Part-132 “No observed effect concentration (NOEC)” C.1.b. (enhanced display)

page 25 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “No observed effect

concentration (NOEC)” C.1.c.

conditions described in procedure 3.E.1.b (or where applicable, with procedure 3.E.1.e) for

Great Lakes System tributaries and connecting channels, with an allowance for mixing

zones no greater than specified pursuant to section A.1 of this procedure.

May specify in the NPDES permit the conditions under which a permittee would be

required to perform a toxicity reduction evaluation.

May allow with respect to any WQBEL established pursuant to section C.1.a of this

procedure an appropriate schedule of compliance consistent with procedure 9 of

appendix F; and

May decide on a case-by-case basis that a WQBEL for WET is not necessary if the State's

or Tribe's water quality standards do not contain a numeric criterion for WET, and the

permitting authority demonstrates in accordance with 40 CFR 122.44(d)(1)(v) that

chemical-specific effluent limits are sufficient to ensure compliance with applicable

criteria.

Where a permitting authority lacks sufficient information to determine pursuant to section D of

this procedure whether the WET of an effluent is or may be discharged at levels that will cause,

have the reasonable potential to cause, or contribute to an excursion above any numeric WET

criterion or narrative criterion within a State's or Tribe's water quality standards, then the

permitting authority should consider including in the NPDES permit appropriate conditions to

require generation of additional data and to control toxicity if found, such as:

WET testing requirements to generate the data needed to adequately characterize the

toxicity of the effluent to aquatic life;

Language requiring a permit reopener clause to establish WET limits if any toxicity testing

data required pursuant to section C.2.a of this procedure indicate that the WET of an

effluent is or may be discharged at levels that will cause, have the reasonable potential to

cause, or contribute to an excursion above any numeric WET criterion or narrative criterion

within a State's or Tribe's water quality standards.

Where sufficient data are available for a permitting authority to determine pursuant to section D

of this procedure that the WET of an effluent neither is nor may be discharged at a level that will

cause, have the reasonable potential to cause, or contribute to an excursion above any numeric

WET criterion or narrative criterion within a State's or Tribe's water quality standards, the

permitting authority may include conditions and limitations described in section C.2 of this

procedure at its discretion.

Reasonable Potential Determinations. The permitting authority shall take into account the factors

described in 40 CFR 122.44(d)(1)(ii) and, where representative facility-specific WET effluent data are

available, apply the following requirements in determining whether the WET of an effluent is or may

be discharged at a level that will cause, have the reasonable potential to cause, or contribute to an

excursion above any numeric WET criterion or narrative criterion within a State's or Tribe's water

quality standards.

The permitting authority shall characterize the toxicity of the discharge by:

Either averaging or using the maximum of acute toxicity values collected within the same

day for each species to represent one daily value. The maximum of all daily values for the

most sensitive species tested is used for reasonable potential determinations;

40 CFR Appendix-F-to-Part-132 “No observed effect concentration (NOEC)” D.1.a. (enhanced display)

page 26 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “No observed effect

concentration (NOEC)” D.1.b.

Either averaging or using the maximum of chronic toxicity values collected within the

same calendar month for each species to represent one monthly value. The maximum of

such values, for the most sensitive species tested, is used for reasonable potential

determinations:

Estimating the toxicity values for the missing endpoint using a default acute-chronic ratio

(ACR) of 10, when data exist for either acute WET or chronic WET, but not for both

endpoints.

The WET of an effluent is or may be discharged at a level that will cause, have the reasonable

potential to cause, or contribute to an excursion above any numeric acute WET criterion or

numeric interpretation of a narrative criterion within a State's or Tribe's water quality standards,

when effluent-specific information demonstrates that:

(TUa effluent) (B) (effluent flow/(Qad + effluent flow))>AC

Where TUa effluent is the maximum measured acute toxicity of 100 percent effluent determined

pursuant to section D.1.a. of this procedure, B is the multiplying factor taken from Table F6–1 of this

procedure to convert the highest measured effluent toxicity value to the estimated 95th percentile

toxicity value for the discharge, effluent flow is the same effluent flow used to calculate the

preliminary wasteload allocations (WLAs) for individual pollutants to meet the acute criteria and

values for those pollutants, AC is the numeric acute WET criterion or numeric interpretation of a

narrative criterion established pursuant to section A.1 of this procedure and expressed in TUa, and

Qad is the amount of the receiving water available for dilution calculated using: (i) the specified

design flow(s) for tributaries and connecting channels in section C.1.b of this procedure, or where

appropriate procedure 3.E.1.e of appendix F, and using EPA-approved State and Tribal procedures for

establishing acute mixing zones in tributaries and connecting channels, or (ii) the EPA-approved

State and Tribal procedures for establishing acute mixing zones in OWGLs. Where there are less than

10 individual WET tests, the multiplying factor taken from Table F6–1 of this procedure shall be

based on a coefficient of variation (CV) or 0.6. Where there are 10 or more individual WET tests, the

multiplying factor taken from Table F6–1 shall be based on a CV calculated as the standard

deviation of the acute toxicity values found in the WET tests divided by the arithmetic mean of those

toxicity values.

The WET of an effluent is or may be discharged at a level that will cause, have the reasonable

potential to cause, or contribute to an excursion above any numeric chronic WET criterion or

numeric interpretation of a narrative criterion within a State's or Tribe's water quality standards,

when effluent-specific information demonstrates that:

(TUc effluent) (B) (effluent flow/Qad + effluent flow))>CC

Where TUc effluent is the maximum measured chronic toxicity value of 100 percent effluent

determined in accordance with section D.1.b. of this procedure, B is the multiplying factor taken from

Table F6–1 of this procedure, effluent flow is the same effluent flow used to calculate the preliminary

WLAs for individual pollutants to meet the chronic criteria and values for those pollutants, CC is the

numeric chronic WET criterion or numeric interpretation of a narrative criterion established pursuant

to section A.2 of this procedure and expressed in TUc, and Qad

is the amount of the receiving water available for dilution calculated using: (i) the design flow(s) for

tributaries and connecting channels specified in procedure 3.E.1.a of appendix F, and where

appropriate procedure 3.E.1.e of appendix F, and in accordance with the provisions of procedure

3.E.5 for chronic mixing zones, or (ii) procedures 3.D.1 and 3.D.4 for discharges to the OWGLs.

40 CFR Appendix-F-to-Part-132 “” D.3. (enhanced display)

page 27 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “” D.3.

Where there are less than 10 individual WET tests, the multiplying factor taken from Table F6–1 of

this procedure shall be based on a CV of 0.6. Where there are 10 more individual WET tests, the

multiplying factor taken from Table F6–1 of this procedure shall be based on a CV calculated as the

standard deviation of the WET tests divided by the arithmetic mean of the WET tests.

40 CFR Appendix-F-to-Part-132 “” D.3. (enhanced display)

page 28 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 “” D.3.

Table F6–1—Reasonable Potential Multiplying Factors: 95% Confidence Level and 95% Probability Basis

Number of Samples

Coefficient of variation

0.1 0.2 0.3 0.4 0.5 0.6 0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

1.4 1.9 2.6 3.6 4.7 6.2 8.0 10.1 12.6 15.5 18.7 22.3 26.4 30.8 35.6 40.7 46.2 52.1 58.4 64.9

1.3 1.6 2.0 2.5 3.1 3.8 4.6

5.4

6.4

7.4

8.5

9.7 10.9 12.2 13.6 15.0 16.4 17.9 19.5 21.1

1.2 1.5 1.8 2.1 2.5 3.0 3.5

4.0

4.6

5.2

5.8

6.5

7.2

7.9

8.6

9.3 10.0 10.8 11.5 12.3

1.2 1.4 1.7 1.9 2.2 2.6 2.9

3.3

3.7

4.2

4.6

5.0

5.5

6.0

6.4

6.9

7.4

7.8

8.3

8.8

1.2 1.4 1.6 1.8 2.1 2.3 2.6

2.9

3.2

3.6

3.9

4.2

4.5

4.9

5.2

5.6

5.9

6.2

6.6

6.9

1.1 1.3 1.5 1.7 1.9 2.1 2.4

2.6

2.9

3.1

3.4

3.7

3.9

4.2

4.5

4.7

5.0

5.2

5.5

5.7

1.1 1.3 1.4 1.6 1.8 2.0 2.2

2.4

2.6

2.8

3.1

3.3

3.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

1.1 1.3 1.4 1.6 1.7 1.9 2.1

2.3

2.4

2.6

2.8

3.0

3.2

3.3

3.5

3.7

3.9

4.0

4.2

4.3

1.1 1.2 1.4 1.5 1.7 1.8 2.0

2.1

2.3

2.4

2.6

2.8

2.9

3.1

3.2

3.4

3.5

3.6

3.8

3.9

1.1 1.2 1.3 1.5 1.6 1.7 1.9

2.0

2.2

2.3

2.4

2.6

2.7

2.8

3.0

3.1

3.2

3.3

3.4

3.6

1.1 1.2 1.3 1.4 1.6 1.7 1.8

1.9

2.1

2.2

2.3

2.4

2.5

2.7

2.8

2.9

3.0

3.1

3.2

3.3

1.1 1.2 1.3 1.4 1.5 1.6 1.7

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

1.1 1.2 1.3 1.4 1.5 1.6 1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

1.1 1.2 1.3 1.4 1.4 1.5 1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

1.1 1.2 1.2 1.3 1.4 1.5 1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.5

1.1 1.1 1.2 1.3 1.4 1.5 1.6

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

1.1 1.1 1.2 1.3 1.4 1.4 1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

1.1 1.1 1.2 1.3 1.3 1.4 1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

1.1 1.1 1.2 1.3 1.3 1.4 1.5

1.5

1.6

1.7

1.8

1.9

2.0

2.1

1.1 1.1 1.2 1.2 1.3 1.4 1.4

1.5

1.6

1.7

1.8

1.9

2.0

1.0 1.1 1.1 1.1 1.2 1.2 1.2

1.3

1.4

1.5

1.0 1.0 1.1 1.1 1.1 1.1 1.1

1.1

1.2

1.3

1.0 1.0 1.0 1.0 1.0 1.0 1.0

1.1

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 0.9

0.9

1.0 1.0 1.0 0.9 0.9 0.9 0.9

0.9

0.8

1.0 1.0 0.9 0.9 0.9 0.9 0.9

0.9

0.8

100

1.0 1.0 0.9 0.9 0.9 0.9 0.9

0.8

0.7

40 CFR Appendix-F-to-Part-132 “” D.3. (enhanced display)

page 29 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 A.

Procedure 7: Loading Limits

The Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this procedure.

Whenever a water quality-based effluent limitation (WQBEL) is developed, the WQBEL shall be expressed as both a

concentration value and a corresponding mass loading rate.

Both mass and concentration limits shall be based on the same permit averaging periods such as daily,

weekly, or monthly averages, or in other appropriate permit averaging periods.

The mass loading rates shall be calculated using effluent flow rates that are consistent with those used in

establishing the WQBELs expressed in concentration.

Procedure 8: Water Quality-based Effluent Limitations Below the Quantification Level

The Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) this procedure.

When a water quality-based effluent limitation (WQBEL) for a pollutant is calculated to be less than the

quantification level:

Permit Limits. The permitting authority shall designate as the limit in the NPDES permit the WQBEL

exactly as calculated.

Analytical Method and Quantification Level.

The permitting authority shall specify in the permit the most sensitive, applicable, analytical method,

specified in or approved under 40 CFR part 136, or other appropriate method if one is not available

under 40 CFR part 136, to be used to monitor for the presence and amount in an effluent of the

pollutant for which the WQBEL is established; and shall specify in accordance with section B.2 of

this procedure, the quantification level that can be achieved by use of the specified analytical

method.

The quantification level shall be the minimum level (ML) specified in or approved under 40 CFR part

136 for the method for that pollutant. If no such ML exists, or if the method is not specified or

approved under 40 CFR part 136, the quantification level shall be the lowest quantifiable level

practicable. The permitting authority may specify a higher quantification level if the permittee

demonstrates that a higher quantification level is appropriate because of effluent-specific matrix

interference.

The permit shall state that, for the purpose of compliance assessment, the analytical method

specified in the permit shall be used to monitor the amount of pollutant in an effluent down to the

quantification level, provided that the analyst has complied with the specified quality assurance/

quality control procedures in the relevant method.

The permitting authority shall use applicable State and Tribal procedures to average and account for

monitoring data. The permitting authority may specify in the permit the value to be used to interpret

sample values below the quantification level.

40 CFR Appendix-F-to-Part-132 B.4. (enhanced display)

page 30 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 C.

Special Conditions. The permit shall contain a reopener clause authorizing modification or revocation and

reissuance of the permit if new information generated as a result of special conditions included in the

permit indicates that presence of the pollutant in the discharge at levels above the WQBEL. Special

conditions that may be included in the permit include, but are not limited to, fish tissue sampling, whole

effluent toxicity (WET) tests, limits and/or monitoring requirements on internal waste streams, and

monitoring for surrogate parameters. Data generated as a result of special conditions can be used to

reopen the permit to establish more stringent effluent limits or conditions, if necessary.

Pollutant Minimization Program. The permitting authority shall include a condition in the permit requiring

the permittee to develop and conduct a pollutant minimization program for each pollutant with a WQBEL

below the quantification level. The goal of the pollutant minimization program shall be to maintain the

effluent at or below the WQBEL. In addition, States and Tribes may consider cost-effectiveness when

evaluating the requirements of a PMP. The pollutant minimization program shall include, but is not limited

to, the following:

An annual review and semi-annual monitoring of potential sources of the pollutant, which may

include fish tissue monitoring and other bio-uptake sampling;

Quarterly monitoring for the pollutant in the influent to the wastewater treatment system;

Submittal of a control strategy designed to proceed toward the goal of maintaining the effluent below

the WQBEL;

Implementation of appropriate, cost-effective control measures consistent with the control strategy;

and

An annual status report that shall be sent to the permitting authority including:

All minimization program monitoring results for the previous year;

A list of potential sources of the pollutant; and

A summary of all action undertaken pursuant to the control strategy.

Any information generated as a result of procedure 8.D can be used to support a request for

subsequent permit modifications, including revisions to (e.g., more or less frequent monitoring), or

removal of the requirements of procedure 8.D, consistent with 40 CFR 122.44, 122.62 and 122.63.

Procedure 9: Compliance Schedules

The Great Lakes States and Tribes shall adopt provisions consistent with (as protective as) procedure 9 of appendix

F of part 132.

Limitations for New Great Lakes Dischargers. When a permit issued on or after March 23, 1997 to a new

Great Lakes discharger (defined in Part 132.2) contains a water quality-based effluent limitation (WQBEL),

the permittee shall comply with such a limitation upon the commencement of the discharge.

Limitations for Existing Great Lakes Dischargers.

Any existing permit that is reissued or modified on or after March 23, 1997 to contain a new or more

restrictive WQBEL may allow a reasonable period of time, up to five years from the date of permit

issuance or modification, for the permittee to comply with that limit, provided that the Tier I criterion

40 CFR Appendix-F-to-Part-132 B.1. (enhanced display)

page 31 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 B.2.

or whole effluent toxicity (WET) criterion was adopted (or, in the case of a narrative criterion, Tier II

value, or Tier I criterion derived pursuant to the methodology in appendix A of part 132, was newly

derived) after July 1, 1977.

When the compliance schedule established under paragraph 1 goes beyond the term of the permit,

an interim permit limit effective upon the expiration date shall be included in the permit and

addressed in the permit's fact sheet or statement of basis. The administrative record for the permit

shall reflect the final limit and its compliance date.

If a permit establishes a schedule of compliance under paragraph 1 which exceeds one year from the

date of permit issuance or modification, the schedule shall set forth interim requirements and dates

for their achievement. The time between such interim dates may not exceed one year. If the time

necessary for completion of any interim requirement is more than one year and is not readily

divisible into stages for completion, the permit shall require, at a minimum, specified dates for

annual submission of progress reports on the status of any interim requirements.

Delayed Effectiveness of Tier II Limitations for Existing Great Lakes Discharges.

Whenever a limit (calculated in accordance with Procedure 3) based upon a Tier II value is included

in a reissued or modified permit for an existing Great Lakes discharger, the permit may provide a

reasonable period of time, up to two years, in which to provide additional studies necessary to

develop a Tier I criterion or to modify the Tier II value. In such cases, the permit shall require

compliance with the Tier II limitation within a reasonable period of time, no later than five years after

permit issuance or modification, and contain a reopener clause.

The reopener clause shall authorize permit modifications if specified studies have been completed

by the permittee or provided by a third-party during the time allowed to conduct the specified studies,

and the permittee or a third-party demonstrates, through such studies, that a revised limit is

appropriate. Such a revised limit shall be incorporated through a permit modification and a

reasonable time period, up to five years, shall be allowed for compliance. If incorporated prior to the

compliance date of the original Tier II limitation, any such revised limit shall not be considered lessstringent for purposes of the anti-backsliding provisions of section 402(o) of the Clean Water Act.

If the specified studies have been completed and do not demonstrate that a revised limit is

appropriate, the permitting authority may provide a reasonable additional period of time, not to

exceed five years with which to achieve compliance with the original effluent limitation.

Where a permit is modified to include new or more stringent limitations, on a date within five years of

the permit expiration date, such compliance schedules may extend beyond the term of a permit

consistent with section B.2 of this procedure.

If future studies (other than those conducted under paragraphs 1, 2, or 3 above) result in a Tier II

value being changed to a less stringent Tier II value or Tier I criterion, after the effective date of a Tier

II-based limit, the existing Tier II-based limit may be revised to be less stringent if:

(a) It complies with sections 402(o) (2) and (3) of the CWA; or,

(b) In non-attainment waters, where the existing Tier II limit was based on procedure 3, the

cumulative effect of revised effluent limitation based on procedure 3 of this appendix will

assure compliance with water quality standards; or,

antidegradation policy and procedures.

40 CFR Appendix-F-to-Part-132 C.5.(c) (enhanced display)

page 32 of 33

Appendix F to Part 132, Title 40 (up to date as of 9/19/2023)

Great Lakes Water Quality Initiative Implementation Procedures

40 CFR Appendix-F-to-Part-132 C.5.(c)

[60 FR 15387, Mar. 23, 1995, as amended at 63 FR 20110, Apr. 23, 1998; 65 FR 67650, Nov. 13, 2000]

40 CFR Appendix-F-to-Part-132 C.5.(c) (enhanced display)

page 33 of 33

40 CFR 122.47 (up to date as of 9/19/2023)

Schedules of compliance.

40 CFR 122.47 (Sept. 19, 2023)

This content is from the eCFR and is authoritative but unofficial.

Title 40 —Protection of Environment

Chapter I —Environmental Protection Agency

Subchapter D —Water Programs

Part 122 —EPA Administered Permit Programs: the National Pollutant Discharge Elimination

System

Subpart C —Permit Conditions

Authority: The Clean Water Act, 33 U.S.C. 1251 et seq.

Source: 48 FR 14153, Apr. 1, 1983, unless otherwise noted.

§ 122.47 Schedules of compliance.

(a) General (applicable to State programs, see § 123.25). The permit may, when appropriate, specify a

schedule of compliance leading to compliance with CWA and regulations.

(1) Time for compliance. Any schedules of compliance under this section shall require compliance as

soon as possible, but not later than the applicable statutory deadline under the CWA.

(2) The first NPDES permit issued to a new source or a new discharger shall contain a schedule of

compliance only when necessary to allow a reasonable opportunity to attain compliance with

requirements issued or revised after commencement of construction but less than three years

before commencement of the relevant discharge. For recommencing dischargers, a schedule of

compliance shall be available only when necessary to allow a reasonable opportunity to attain

compliance with requirements issued or revised less than three years before recommencement of

discharge.

(3) Interim dates. Except as provided in paragraph (b)(1)(ii) of this section, if a permit establishes a

schedule of compliance which exceeds 1 year from the date of permit issuance, the schedule shall

set forth interim requirements and the dates for their achievement.

(i)

The time between interim dates shall not exceed 1 year, except that in the case of a schedule

for compliance with standards for sewage sludge use and disposal, the time between interim

dates shall not exceed six months.

(ii) If the time necessary for completion of any interim requirement (such as the construction of a

control facility) is more than 1 year and is not readily divisible into stages for completion, the

permit shall specify interim dates for the submission of reports of progress toward completion

of the interim requirements and indicate a projected completion date.

Note: Examples of interim requirements include: (a) Submit a complete Step 1

construction grant (for POTWs); (b) let a contract for construction of required facilities;

facilities.

40 CFR 122.47(a)(3)(ii) (enhanced display)

page 1 of 2

40 CFR 122.47 (up to date as of 9/19/2023)

Schedules of compliance.

40 CFR 122.47(a)(4)

(4) Reporting. The permit shall be written to require that no later than 14 days following each interim

date and the final date of compliance, the permittee shall notify the Director in writing of its

compliance or noncompliance with the interim or final requirements, or submit progress reports if

paragraph (a)(3)(ii) is applicable.

(b) Alternative schedules of compliance. An NPDES permit applicant or permittee may cease conducting

regulated activities (by terminating of direct discharge for NPDES sources) rather than continuing to

operate and meet permit requirements as follows:

(1) If the permittee decides to cease conducting regulated activities at a given time within the term of a

permit which has already been issued:

(i)

The permit may be modified to contain a new or additional schedule leading to timely cessation

of activities; or

(ii) The permittee shall cease conducting permitted activities before non-compliance with any

interim or final compliance schedule requirement already specified in the permit.

(2) If the decision to cease conducting regulated activities is made before issuance of a permit whose

term will include the termination date, the permit shall contain a schedule leading to termination

which will ensure timely compliance with applicable requirements no later than the statutory

deadline.

(3) If the permittee is undecided whether to cease conducting regulated activities, the Director may

issue or modify a permit to contain two schedules as follows:

(i)

Both schedules shall contain an identical interim deadline requiring a final decision on whether

to cease conducting regulated activities no later than a date which ensures sufficient time to

comply with applicable requirements in a timely manner if the decision is to continue

conducting regulated activities;

(ii) One schedule shall lead to timely compliance with applicable requirements, no later than the

statutory deadline;

(iii) The second schedule shall lead to cessation of regulated activities by a date which will ensure

timely compliance with applicable requirements no later than the statutory deadline.

(iv) Each permit containing two schedules shall include a requirement that after the permittee has

made a final decision under paragraph (b)(3)(i) of this section it shall follow the schedule

leading to compliance if the decision is to continue conducting regulated activities, and follow

the schedule leading to termination if the decision is to cease conducting regulated activities.

(4) The applicant's or permittee's decision to cease conducting regulated activities shall be evidenced by

a firm public commitment satisfactory to the Director, such as a resolution of the board of directors

of a corporation.

[48 FR 14153, Apr. 1, 1983, as amended at 49 FR 38050, Sept. 26, 1984; 50 FR 6940, Feb. 19, 1985; 54 FR 18784, May 2, 1989; 65

FR 30909, May 15, 2000]

40 CFR 122.47(b)(4) (enhanced display)

page 2 of 2

Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Tables to Part 132, Title 40 (Oct. 1, 2024)

This content is from the eCFR and is authoritative but unofficial.

Title 40 —Protection of Environment

Chapter I —Environmental Protection Agency

Subchapter D —Water Programs

Part 132 —Water Quality Guidance for the Great Lakes System

Authority: 33 U.S.C. 1251 et seq.

Source: 60 FR 15387, Mar. 23, 1995, unless otherwise noted.

Tables to Part 132

Table 1—Acute Water Quality Criteria for Protection of Aquatic Life in Ambient Water

EPA recommends that metals criteria be expressed as dissolved concentrations (see appendix A, I.A.4 for more

information regarding metals criteria).

(a)

Chemical

CMC

(µg/L)

Conversion factor (CF)

Arsenic (III)

a b 339.8

1.000

Chromium (VI)

a b 16.02

0.982

Cyanide

c 22

n/a

Dieldrin

d 0.24

n/a

Endrin

d 0.086

n/a

Lindane

d 0.95

n/a

a b 1.694

0.85

Mercury (II)

a CMC = CMCtr.

b CMCd = (CMCtr) CF. The CMCd shall be rounded to two significant digits.

c CMC should be considered free cyanide as CN.

d CMC = CMCt.

Notes:

The term “n/a” means not applicable.

CMC is Criterion Maximum Concentration.

CMCtr is the CMC expressed as total recoverable.

CMCd is the CMC expressed as a dissolved concentration.

CMCt is the CMC expressed as a total concentration.

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

page 1 of 13

Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Chemical

Tables to Part 132, Title 40 (Oct. 1, 2024)

CMC

(µg/L)

Parathion

Conversion factor (CF)

0.065

n/a

CMC = CMC .

CMCd = (CMCtr) CF. The CMCd shall be rounded to two significant digits.

CMC should be considered free cyanide as CN.

CMC = CMCt.

Notes:

The term “n/a” means not applicable.

CMC is Criterion Maximum Concentration.

CMCtr is the CMC expressed as total recoverable.

CMCd is the CMC expressed as a dissolved concentration.

CMCt is the CMC expressed as a total concentration.

(b)

Chemical

Conversion factor (CF)

Cadmiuma b

1.128

−3.6867

0.85

Chromium (III)a b

0.819

+ 3.7256

0.316

Coppera b

0.9422

−1.700

0.960

Nickela b

0.846

+ 2.255

0.998

Pentachlorophenolc

1.005

−4.869

n/a

Zinca b

0.8473

+ 0.884

0.978

a CMCtr = exp {m

A [ln (hardness)] + bA}.

b CMCd = (CMCtr) CF. The CMCd shall be rounded to two significant digits.

c CMCt = exp m

A {[pH] + bA}. The CMC shall be rounded to two significant digits.

Notes:

The term “exp” represents the base e exponential function.

The term “n/a” means not applicable.

CMC is Criterion Maximum Concentration.

CMCtr is the CMC expressed as total recoverable.

CMCd is the CMC expressed as a dissolved concentration.

CMCt is the CMC expressed as a total concentration.

[60 FR 15387, Mar. 23, 1995, as amended at 65 FR 35286, June 2, 2000]

Table 2—Chronic Water Quality Criteria for Protection of Aquatic Life in Ambient Water

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

page 2 of 13

Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Tables to Part 132, Title 40 (Oct. 1, 2024)

EPA recommends that metals criteria be expressed as dissolved concentrations (see appendix A, I.A.4 for more

information regarding metals criteria).

(a)

Chemical

CCC

(µg/L)

Conversion factor (CF)

Arsenic (III)

147.9

1.000

Chromium (VI)

10.98

0.962

Cyanide

5.2

n/a

Dieldrin

0.056

n/a

Endrin

d 0.036

n/a

a b 0.9081

0.85

d 0.013

n/a

Mercury (II)

Parathion

a CCC = CCCtr.

b CCCd = (CCCtr) CF. The CCCd shall be rounded to two significant digits.

c CCC should be considered free cyanide as CN.

d CCC = CCCt.

Notes:

The term “n/a” means not applicable.

CCC is Criterion Continuous Concentration.

CCCtr is the CCC expressed as total recoverable.

CCCd is the CCC expressed as a dissolved concentration.

CCCt is the CCC expressed as a total concentration.

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

page 3 of 13

Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Chemical

Tables to Part 132, Title 40 (Oct. 1, 2024)

CCC

(µg/L)

Conversion factor (CF)

Selenium

0.922

CCC = CCC .

CCCd = (CCCtr) CF. The CCCd shall be rounded to two significant digits.

CCC should be considered free cyanide as CN.

CCC = CCCt.

Notes:

The term “n/a” means not applicable.

CCC is Criterion Continuous Concentration.

CCCtr is the CCC expressed as total recoverable.

CCCd is the CCC expressed as a dissolved concentration.

CCCt is the CCC expressed as a total concentration.

(b)

Chemical

Conversion factor

(CF)

Cadmiuma b

0.7852

−2.715

0.850

Chromium (III)a b

0.819

+ 0.6848

0.860

Coppera b

0.8545

−1.702

0.960

Nickela b

0.846

+ 0.0584

0.997

Pentachlorophenolc

1.005

−5.134

n/a

a CCCtr = exp {m [ln (hardness)] + b }.

b CCC = (CCCtr) (CF). The CCCd shall be rounded to two significant digits.

CMCt = exp {mA[pH] + bA}. The CMCt shall be rounded to two significant digits.

Notes:

The term “exp” represents the base e exponential function.

The term “n/a” means not applicable.

CCC is Criterion Continuous Concentration.

CCCtr is the CCC expressed as total recoverable.

CCCd is the CCC expressed as a dissolved concentration.

CCCt is the CCC expressed as a total concentration.

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

page 4 of 13

Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Chemical

Tables to Part 132, Title 40 (Oct. 1, 2024)

Conversion factor

(CF)

0.8473

+ 0.884

Zinca b

0.986

CCC = exp {mc[ln (hardness)] + bc}.

CCCd = (CCCtr) (CF). The CCCd shall be rounded to two significant digits.

CMCt = exp {mA[pH] + bA}. The CMCt shall be rounded to two significant digits.

Notes:

The term “exp” represents the base e exponential function.

The term “n/a” means not applicable.

CCC is Criterion Continuous Concentration.

CCCtr is the CCC expressed as total recoverable.

CCCd is the CCC expressed as a dissolved concentration.

CCCt is the CCC expressed as a total concentration.

TABLE 3—WATER QUALITY CRITERIA FOR PROTECTION OF HUMAN HEALTH

Chemical

HNV (µg/L)

Drinking

HCV (µg/L)

Nondrinking

Drinking

Nondrinking

Benzene

1.9E1

5.1E2

1.2E1

3.1E2

Chlordane

1.4E-3

2.5E-4

Chlorobenzene

4.7E2

3.2E3

Cyanides

6.0E2

4.8E4

DDT

2.0E-3

1.5E-4

Dieldrin

4.1E-4

6.5E-6

2,4-Dimethylphenol

4.5E2

8.7E3

2,4-Dinitrophenol

5.5E1

2.8E3

Hexachlorobenzene

4.6E-2

4.5E-4

6.0

7.6

5.3

6.7

Lindane

4.7E-1

5.0E-1

Mercury1

1.8E-3

Methylene chloride

1.6E3

9.0E4

4.7E1

2.6E3

2,3,7,8-TCDD

6.7E-8

8.6E-9

Toluene

5.6E3

5.1E4

6.8E-5

Hexachloroethane

Toxaphene

1 Includes methylmercury.

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

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Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Chemical

Tables to Part 132, Title 40 (Oct. 1, 2024)

HNV (µg/L)

Drinking

Nondrinking

Trichloroethylene

HCV (µg/L)

Drinking

Nondrinking

2.9E1

3.7E2

Includes methylmercury.

[60 FR 15387, Mar. 23, 1995, as amended at 62 FR 11731, Mar. 12, 1997; 62 FR 52924, Oct. 9, 1997]

TABLE 4—WATER QUALITY CRITERIA FOR PROTECTION OF WILDLIFE

Chemical

Criteria (µg/L)

DDT and metabolites

1.1E-5

Mercury (including methylmercury)

1.3E-3

PCBs (class)

1.2E-4

2,3,7,8-TCDD

3.1E-9

[60 FR 15387, Mar. 23, 1995, as amended at 62 FR 11731, Mar. 12, 1997]

Table 5—Pollutants Subject to Federal, State, and Tribal Requirements

Alkalinity

Ammonia

Bacteria

Biochemical oxygen demand (BOD)

Chlorine

Color

Dissolved oxygen

Dissolved solids

Phosphorus

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

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Tables to Part 132, Title 40 (up to date as of 10/01/2024)

Tables to Part 132

Tables to Part 132, Title 40 (Oct. 1, 2024)

Salinity

Temperature

Total and suspended solids

Turbidity

Table 6—Pollutants of Initial Focus in the Great Lakes Water Quality Initiative

Pollutants that are bioaccumulative chemicals of concern (BCCs):

Chlordane

4,4′-DDD; p,p′-DDD; 4,4′-TDE; p,p′-TDE

4,4′-DDE; p,p′-DDE

4,4′-DDT; p,p′-DDT

Dieldrin

Hexachlorobenzene

Hexachlorobutadiene; hexachloro-1, 3-butadiene

Hexachlorocyclohexanes; BHCs

alpha-Hexachlorocyclohexane; alpha-BHC

beta-Hexachlorocyclohexane; beta-BHC

delta-Hexachlorocyclohexane; delta-BHC

Lindane; gamma-hexachlorocyclohexane; gamma-BHC

Mercury

Mirex

Octachlorostyrene

PCBs; polychlorinated biphenyls

Pentachlorobenzene

Tables to Part 132, Title 40 (Oct. 1, 2024) (enhanced display)

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