Rule 17.30.646 - BIOASSAYS(1) Bioassay tolerance concentrations must be determined using the latest available research results for the materials, by bioassay tests procedures for simulating actual stream conditions as set forth in 40 CFR Part 136 (July 1, 2007 2015). Any bioassay studies made must be made using a representative sensitive local species and life stages of economic or ecological importance, except that other species whose relative sensitivity is known may be used when there is difficulty in providing the more sensitive species in sufficient numbers or when such species are unsatisfactory for routine confined bioassays. All bioassay methods and species selections must be approved by the department.Mont. Admin. r. 17.30.646
Eff. 12/31/72; AMD, Eff. 11/4/73; AMD, Eff. 9/5/74; AMD, 1980 MAR p. 2252, Eff. 8/1/80; AMD, 1988 MAR p. 1191, Eff. 6/10/88; TRANS, from DHES, 1996 MAR p. 1499; AMD, 2002 MAR p. 387, Eff. 2/15/02; AMD, 2008 MAR p. 946, Eff. 5/9/08; AMD, 2017 MAR p. 602, Eff. 5/13/2017AUTH: 75-5-201, 75-5-301, MCA IMP: 75-5-301, MCA