NR 106.145 Note Note: Permittees that do not prepare or effectively implement a pollutant minimization program are subject to regulatory requirements for mercury, without alternative mercury effluent limitations to water quality standards. For municipal permittees this may mean development and enforcement of mercury discharge standards for users of the public sewerage system pursuant to s. NR 211.10 (3). For users of the municipal sewerage system this may mean changes in processes, installation of treatment technology, or other means to comply with the municipal mercury discharge standards pursuant to s. NR 211.10 (1). Implementation of the municipal mercury discharge standards may require a program of user discharge permits and wastewater discharge monitoring.

NR 106.145(8) (8) Alternative mercury effluent limitation applications.

NR 106.145(8)(a) (a) To apply for an alternative mercury effluent limitation under this section, a permittee shall do all of the following:

NR 106.145(8)(a)1. 1. Submit an alternative mercury effluent limitation application at the same time as the application for permit reissuance following data generation.

NR 106.145(8)(a)2. 2. State the basis for concluding that wastewater treatment technology for mercury is impractical.

NR 106.145(8)(a)3. 3. Supply representative effluent monitoring results of sufficient number and analytical sensitivity to quantify with reasonable certainty the concentration and mass of mercury discharged. Representative sample results shall meet all of the following requirements:

NR 106.145(8)(a)3.a. a. Be of sufficient quantity to allow calculation of the upper 99th percentile values pursuant to s. NR 106.05 (5).

NR 106.145(8)(a)3.b. b. Reasonably represent current conditions.

NR 106.145(8)(a)3.c. c. Meet the data quality requirements of subs. (9) and (10).

NR 106.145(8)(a)3.d. d. Represent a time period of at least 2 years.

NR 106.145(8)(a)4. 4. Submit a pollution minimization program plan described in sub. (7) (f).

NR 106.145(8)(b) (b) A permittee applying for renewal of an alternative mercury effluent limitation previously granted shall follow the procedures in par. (a) except for all of the following:

NR 106.145(8)(b)1. 1. The permittee shall submit information indicating whether the permittee substantially complied with mercury regulation conditions of the existing permit.

NR 106.145(8)(b)2. 2. A new pollutant minimization program plan shall re-evaluate the plan required under the previous permit.

NR 106.145(9) (9) Sampling requirements.

NR 106.145(9)(a) (a) Sample types may be grab or 24-hour composite. “Grab sample” and “24-hour composite sample” have the meanings specified in s. NR 218.04.

NR 106.145(9)(b) (b) Sample collection methods shall be consistent with EPA Method 1669: Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria Levels, EPA-821-R-96-011.

NR 106.145(9)(c) (c) Requirements for field blanks are as follows. A field blank means an aliquot of mercury-free reagent water that is placed in a sample container, shipped to the field and treated as a sample in all respects, including contact with the sampling devices and exposure to sampling site conditions, filtration, storage, preservation, and all analytical procedures. The purpose of the field blank is to determine whether the field or sample transporting procedures and environments have contaminated the sample:

NR 106.145(9)(c)1. 1. At least one field blank shall be collected at each site for each day a sample is collected. If more than one sample is collected in a day, at least one field blank for each 10 samples collected on that day shall be collected.

NR 106.145(9)(c)2. 2. If mercury or any potentially interfering substance is found in the field blank at a concentration equal to or greater than 0.5 ng/L, the limit of detection or one-fifth the level in the associated sample, whichever is greater, results for associated samples may not be used for regulatory compliance purposes unless the conditions in subd. 3. are met.

NR 106.145(9)(c)3. 3. If at least 3 field blanks are collected on a day when samples are collected and the average mercury concentration of the field blanks plus 2 standard deviations is less than or equal to one-half of the level in the associated sample or less than the lowest water quality criterion for mercury found in ch. NR 105, whichever is greater, results may be used.

NR 106.145 Note Note: As of November 1, 2002 the lowest water quality criterion listed in ch. NR 105 is 1.3 ng/L.

NR 106.145(9)(c)4. 4. Once a permittee demonstrates the ability to collect samples from a given site using an established procedure that meets the use-criteria of subd. 2., the permittee may decrease the number of field blanks to no fewer than one field blank for each 4 sampling days.

NR 106.145(9)(c)4.a. a. The initial demonstration shall consist of at least 6 consecutive sampling days.

NR 106.145(9)(c)4.b. b. If the permittee makes significant changes to the sampling procedure or sampling personnel, the 6-day demonstration shall be repeated.

NR 106.145(9)(c)4.c. c. If after reducing the field blank frequency, a field blank fails to meet the use-criteria, the permittee shall take corrective action and return to collecting field blanks on each sampling day until it can meet the use-criteria for at least 3 consecutive sampling days.

NR 106.145(9)(c)4.d. d. In no case may the permittee decrease field blanks to fewer than one for each 10 samples.

NR 106.145(9)(c)5. 5. The permittee shall report, but may not subtract, field blank concentrations when reporting sample results.

NR 106.145 Note Note: When using the data, the department may subtract field blanks from sample concentrations on a case-by-case basis.