Wisconsin Legislature: 002 - CR 15-085 Rule Text

NR 106.07 (4) Note: This methodology is based on the Technical Support Document for Water Quality-based Toxics Control (March 1991). PB91-127415.

Section 27 NR 106.07 (5) is repealed and recreated to read:

NR 106.07 (5) Expression of concentration limitations in permits for noncontinuous discharges. (a) Applicability. The procedures for expressing limitations in this subsection apply to seasonal discharges, discharges proportional to stream flow, or other unusual discharge situations that do not meet the definition of a continuous discharge pursuant to s. NR 205.03 (9g) where there is reasonable potential under s. NR 106.05 to exceed a water quality based effluent limitation based on fish and aquatic life protection, human health or wildlife protection. Water quality based effluent limitations shall be calculated pursuant to s. NR 106.06.

(b) Acute Reasonable Potential. Pursuant to s. NR 106.05, if there is reasonable potential to exceed a water quality based effluent limitation for a pollutant that is based on an acute criterion or secondary value then the acute concentration limitation calculated under s. NR 106.06 shall be expressed as a daily maximum and included in the permit.

(c) Chronic and Human Health or Wildlife Reasonable Potential. Pursuant to s. NR 106.05, if there is reasonable potential to exceed a water quality based effluent limitation for a pollutant based on a chronic, a human health or wildlife criterion or secondary value, limitations shall be included in the permit and expressed on a case-by-case basis. The Department shall consider the following factors:

1. Frequency and duration of discharge

2. Total mass of discharge

3. Maximum flow rate of discharge

4. Whether the pollutant is subject to a technology based limitation or other limitation expressed by mass, concentration, or other appropriate measure in the WPDES permit.

Section 28 NR 106.07 (5m) and (title) are created to read:

NR 106.07 (5m) Coefficient of variation. (a) The coefficient of variation (CV) shall be calculated as the ratio of the standard deviation of the representative effluent data divided by the arithmetic average of the representative effluent data, except as provided in par. (b).

(b) If there are fewer than ten representative data points the CV shall be set equal to 0.6.

(c) When calculating the CV in par. (a) a monitoring result less than the limit of detection may be assigned a value of zero. If the effluent limitation is less than the limit of detection, the department may substitute a value other than zero for results less than the limit of detection, after considering the number of monitoring results that are greater than the limit of detection and if warranted when applying appropriate statistical techniques.

Section 29 NR 106.07 (6) (title) is created to read:

NR 106.07 (6) (title) Monitoring and compliance with limitations below the level of detection.

Section 30 NR 106.07 (7) (title) is created to read:

NR 106.07 (7) (title) Whole effluent toxicity as alternative limit.

Section 31 NR 106.07 (8) (title) is created to read:

NR 106.07 (8) (title) Secondary values and studies within the great lakes basin.

Section 32 NR 106.07 (8) is amended to read:

NR 106.07 (8) If the effluent limitation based on a secondary value is established in a permit, the permittee permittees discharging to the Great Lakes basin may request that additional time be added to the compliance schedule, according to s. NR 106.117 (2), for the permittee to conduct studies, other than studies for site-specific criteria pursuant to s. NR 105.02 (1), that are needed to propose a revision to the secondary value upon which the effluent limitation is based. During this time, the permittee may provide additional data necessary to either refine the secondary value or calculate a water quality criterion.

Section 33 NR 106.07 (9) (title) is create to read:

NR 106.07 (9) (title) Wet weather mass limitations.

Section 34 NR 106.07 (10) and (title) is created to read:

NR 106.07 (10) (title) Alternative methods for limit expression. The department may use an alternative method from the methodology specified in subs. (3) through (5) to express water quality based effluent limitations in WPDES permits if the department determines that the methods in subs. (3)-(5) are impracticable and an alternative methodology is necessary and appropriate and adequately protective of the designated uses of the receiving and downstream waters as specified in ch. NR 102.

Section 35 NR 106.08 is repealed and recreated to read:

NR 106.08 (1) General. The department shall establish whole effluent toxicity testing requirements and limitations whenever necessary to meet applicable water quality standards as specified in chs. NR 102 to 105 as measured by exposure of aquatic organisms to an effluent and specified effluent dilutions. When considering the necessity for whole effluent toxicity testing requirements and limitations, the department shall consider in-stream biosurvey data and data from ambient toxicity analyses, whenever such data are available.

(2) Determination of necessity. If representative discharge data are available for an effluent being discharged from a point source, whole effluent toxicity testing requirements are necessary when:

(a) Existing aquatic life toxicity test data generated according to standard test protocols indicate a potential for an effluent from a point source discharge to adversely impact the receiving water aquatic life community.

(b) A water quality based effluent limitation for a toxic substance is determined necessary in s. NR 106.05.

(3) Representative data. Toxicity test data available to the department shall be considered representative when those data meet the following conditions:

(a) Data are representative of normal discharge conditions and current effluent quality;

(b) Data were produced by a lab certified or registered under ch. NR 149;

(d) Data were produced from toxicity tests that met all applicable quality assurance/quality control requirements specified in the WPDES permit.

(4) No representative data. If no representative discharge data are available for an effluent being discharged from a point source, whole effluent toxicity testing requirements are necessary if, in the judgment of the department, water quality standards may be exceeded. In such cases, all of the following factors shall be considered:

(a) Any relevant information which is available that indicates a potential for an effluent to impact the receiving water aquatic life community.

(b) Available dilution in the receiving water.

(d) Proximity to other point source dischargers.

(5) Other considerations. Regardless of the results of the analysis conducted under this section, the department may, whenever determined necessary, require whole effluent toxicity testing for a point source discharge. The department may use information submitted under s. 323.60 (5) (c) and (d), Stats., together with other information, in determining when whole effluent toxicity testing is necessary.

(6) Reasonable potential to receive an acute or chronic whole effluent toxicity limit. (a) General. Whole effluent toxicity limits are established in a permit according to s. NR 106.09 whenever representative, facility-specific whole effluent toxicity data demonstrate that the effluent is or may be discharged at a level that will cause, have the potential to cause, or contribute to an excursion of a water quality standard. Whole effluent toxicity limits may also be imposed in the absence of facility-specific whole effluent toxicity test data, on a case-by-case basis, whenever facility-specific or site-specific data or conditions indicate toxicity to aquatic life that is attributable to the discharger.

(b) Reasonable potential.

1. If a zone of initial dilution has not been approved by the department, the potential to exceed an acute criterion shall be calculated using the following equation:

(TUa effluent) (B) > 1.0

Where:

TUa effluent= maximum calculated TUa from the most sensitive species in the data set

B= Reasonable potential multiplication factor determined under par. (c)

1.0= Numeric acute WET limitation in acute toxic units (TUa) derived from narrative criterion in s. NR 102.04(1)(d)

2. If a zone of initial dilution has been approved by the department, the potential to exceed an acute criterion shall be calculated using the following equation:

[(TUa effluent) (B) (AMZ)] > 1.0

Where:

TUa effluent= Maximum calculated TUa from the most sensitive species in the data set

B= Reasonable potential multiplication factor determined under par. (c)

AMZ= Acute mixing zone concentration based on presence of a zone of initial dilution as defined in s. NR 106.03(1) expressed as a decimal

1.0= Numeric acute WET limitation in acute toxic units (TUa) derived from narrative criterion in s. NR 102.04(1)(d)

3. The potential to exceed a chronic criterion shall be calculated using the following equation:

[(TUc effluent) (B) (IWC)]> 1.0

Where:

TUc effluent= Maximum calculated TUc from the most sensitive species in the data set

B= Reasonable potential multiplication factor determined under par. (c)

IWC= Instream waste concentration as defined in s. NR 106.03(6) expressed as a decimal

1.0= Numeric chronic WET limitation in chronic toxic units (TUc) derived from narrative criterion in s. NR 102.04(4)(d)

(c) Reasonable potential multiplication factor. The reasonable potential multiplication factor in par. (b) is used to convert the calculated effluent toxicity value to the estimated 95th percentile toxicity value. The department shall use all of the following methods to select a reasonable potential multiplication factor:

1. Where there are less than 10 individual toxicity detects, the multiplication factor shall be taken from Table 4 and based on a coefficient of variation of 0.6.

2. Where there are 10 or more individual toxicity detects, the multiplication factor shall be taken from Table 4 and based on coefficient of variation calculated as the standard deviation of the WET test endpoints (IC25, IC50 or LC50) divided by the arithmetic mean of the WET tests.

NR 106.08 (5) (c) Table 4 — Reasonable Potential Multiplication Factor.

Coefficient of variation (CV)

Number of samples (n)

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

6.2

3.8

3.0

2.6

2.3

2.1

2.0

1.9

1.8

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

1.5

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

1.3

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

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

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

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

2.1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

1.0

1.1

1.2

1.3

1.4

1.5

1.0

1.1

1.2

1.3

1.0

1.1

1.0

0.9

1.0

0.9

0.8

1.0

0.9

0.8

100

1.0

0.9

0.8

0.7

(d) Maximum toxicity values. The Department shall set the TUc effluent and TUa effluent values in par. (b) equal to zero whenever toxicity is not-detected or the LC50, IC25, or IC50 equals or exceeds 100% effluent.

(7) Data Exclusions. The Department may exclude data from a WET reasonable potential determination when those data meet any of the following conditions:

(a) Data are not representative pursuant to sub. (3);

(b) Positive WET results are caused by deficiency toxicity only; or

(c) Positive WET results are caused by groundwater or surface water remediation needed to correct or prevent an existing surface or groundwater contamination situation or a public health problem.

Section 36 NR 106.09 (2) (e) is repealed and recreated to read:

NR 106.09 (2) (e) Acute whole effluent toxicity limits shall be expressed as 1.0 TUa unless an AMZ is approved in which case these limits shall be expressed as a value that is 100 divided by the AMZ. Compliance with an acute whole effluent toxicity water quality based limitation shall be determined by comparing the TUa endpoint from each toxicity test to the limitation. Pursuant to s. NR 106.08(6)(d) a calculated LC50 that exceeds 100% is set equal to zero.

Section 37 NR 106.09 (2) (f) is created to read:

NR 106.09 (2) (f) Whole effluent acute toxicity limitations shall be expressed in permits as daily maximum limitations.

Section 38 NR 106.09 (3) (b) is amended to read:

NR 106.09 (3) (b) To assure compliance with par. (a), an effluent, after dilution with an appropriate allowable quantity of receiving water flow equivalent to that provided by receiving water flows specified in s. NR 106.06(4)(c) NR 106.06(3)(c) or implied in s. NR 106.06(4)(b)2. NR 106.06(3)(b)2., may not cause a significant adverse effect, as determined by subds. 1. and 2., to a test organism population when compared to an appropriate control.

Section 39 NR 106.09 (3) (b) 1. is amended to read:

NR 106.09 (3) (b) 1. Using statistical interpretation methods appropriate to the toxicity test protocol, an adverse effect will be determined to be significant if the statistically derived IC25 or IC50, as specified for each species in the whole effluent toxicity test methods required in s. NR 219.04, Table A, from the whole effluent toxicity test, is less than the calculated IWC.

Section 40 NR 106.09 (3) (c) is repealed and recreated to read:

NR 106.09 (3) (c) Chronic whole effluent toxicity limits shall be expressed as a value that is 100 divided by the IWC. Compliance with a chronic whole effluent toxicity water quality based limitation shall be determined by comparing the monthly average calculated TUc from all toxicity tests conducted during that month to the limitation. Pursuant to s. NR 106.08(6)(d) a calculated IC25 or IC50 that exceeds 100% is set equal to zero.

Section 41 NR 106.09 (3) (d) is created to read:

NR 106.09 (3) (d) Whole effluent chronic toxicity limitations shall be expressed in permits as monthly average limitations.

Section 42 NR 106.11 (note) is created to read:

NR 106.11 Note: The method of allocating the combined allowable load in to s. NR 106.11 does not have to be based on the effluent flow rates specified in s. NR 106.04(4)(d).

Section 43 NR 106.115 Table 1 (title) and Table 2 (title) are amended to read: