NR 106.01NR 106.01 Purpose. One purpose of this chapter is to specify how the department will calculate water quality based effluent limitations under s. 283.13 (5), Stats., for toxic and organoleptic substances and whole effluent toxicity. The other purpose of this chapter is to specify how the department will decide if and how these limitations will be included in Wisconsin pollution discharge elimination system (WPDES) permits. Water quality based effluent limitations for toxic and organoleptic substances are needed to assure attainment and maintenance of surface water quality standards as established in accordance with s. 281.15 (1), Stats., and as set forth in chs. NR 102 to 105.

NR 106.01 HistoryHistory: Cr. Register, February, 1989, No. 398, eff. 3-1-89; correction made under s. 13.93 (2m) (b) 7., Stats., Register October 2002 No. 562.

NR 106.02NR 106.02 Applicability. The provisions of this chapter are applicable to point sources which discharge wastewater containing toxic or organoleptic substances to surface waters of the state.

NR 106.03NR 106.03 Definitions. The following definitions are applicable to terms used in this chapter.

NR 106.03(1g)(1g) “AMZ” means acute mixing zone concentration based on presence of a zone of initial dilution under s. NR 106.06 (3) (c).

NR 106.03(1r)(1r) “Bioaccumulative chemical of concern” or “BCC” means any substance that has the potential to cause adverse effects which, upon entering the surface waters, accumulates in aquatic organisms by a human health or wildlife bioaccumulation factor greater than 1000.

NR 106.03(2)(2) “Biologically based design flow” means a receiving water design flow to protect fish and aquatic life for which both the duration of exposure is expressed in days and the allowable frequency of excursion is expressed in years. An example of a biologically based design flow is a 4-day 3-year design flow which corresponds to the lowest 4-day average flow that will limit excursions from any water quality criteria or secondary values to no more than once in 3 years.

NR 106.03(2m)(2m) “Deficiency toxicity” means a condition that exists when adverse effects occur to aquatic organisms because concentrations of common ions are too low.

NR 106.03 NoteNote: Changes in the concentration of ions in surrounding waters can cause organisms to expend too much energy trying to regulate the balance of water and dissolved materials in bodily fluids, and may result in death.

NR 106.03(3)(3) “Dynamic models” means computer simulation models which use real or derived time series data to predict a time series of observed or derived receiving water concentrations. Methods include continuous simulation, Monte Carlo simulations, or other similar statistical or deterministic techniques.

NR 106.03(4)(4) “EC50” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture which causes an adverse effect including mortality to 50% of the exposed organisms in a given time period, when compared to an appropriate control.

NR 106.03(4g)(4g) “Great Lakes” means the open Wisconsin waters of Lake Superior, Lake Michigan, Green Bay, and Chequamegon Bay, as well as adjoining open waters that exhibit characteristics of Lake Superior, Lake Michigan, Green Bay, and Chequamegon Bay, or in other ways are determined by the department to be equivalent to these waters.

NR 106.03(5)(5) “IC25” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture that would cause a 25% reduction in a nonlethal biological measurement, such as reproduction or growth, of the exposed test organisms in a given time period.

NR 106.03(5m)(5m) “IC50” means the point estimate of the concentration of a toxic substance, wastewater effluent or other aqueous mixture that would cause a 50% reduction in a nonlethal biological measurement, such as reproduction or growth, of the exposed test organisms in a given time period.