(1) For the purposes of this subchapter, the department adopts and incorporates by reference:
(a) Department Circular DEQ-7, "Montana Numeric Water Quality Standards" (June 2019 edition);
(b) Drinking Water Maximum Contaminant Levels, published at 40 CFR 141.11, 40 CFR 141.61, 40 CFR 141.62, 40 CFR 141.63, 40 CFR 141.64, 40 CFR 141.65, and 40 CFR 141.66 (2010);
(c) Montana Risk-based Corrective Action Guidance for Petroleum Releases (May 2018);
(d) U.S. Environmental Protection Agency, Regional Screening Level (RSL) Tables (November 2018), except when:
(i) comparing contaminant concentrations to the regional screening levels, with the exception of lead, the department will adjust the non-carcinogenic levels by dividing by ten to account for cumulative potential health effects;
(ii) comparing contaminant concentrations to the protection of ground water soil screening levels, the department will adjust the dilution attenuation factor to ten to account for a state-specific attenuation factor;
(iii) comparing contaminant concentrations to the protection of ground water soil screening levels, the department will apply an appropriate adjustment based upon either the ratio of the department Circular DEQ-7 human health standard and the maximum contaminant level or the ratio of the department Circular DEQ-7 human health standard and the U.S. Environmental Protection Agency tapwater screening level found in (1)(d) to ensure that contaminants potentially leaching to ground water will not exceed Montana numeric water quality standards found in Department Circular DEQ-7;
(e) Montana Department of Environmental Quality, Remediation Division, Table 4-4, Background Concentrations of Inorganic Constituents in Montana Surface Soil (September 2013); and
(f) U.S. Environmental Protection Agency Region 3 Biological Technical Assistance Group Freshwater Sediment Screening Benchmarks (August 2006).
(2) All references in this subchapter to the documents incorporated by reference in this rule are to the edition specified in this rule.
(3) Copies of the documents incorporated by reference in this rule may be obtained from the Department of Environmental Quality, Remediation Division, P.O. Box 200901, Helena, MT 59620-0901.
(4) The references adopted in (1)(c) through (1)(f) are to be used as screening levels. When the department uses screening levels referenced in (1)(d) and (1)(e) rather than site-specific data to make a listing decision under ARM 17.55.108, it shall use the higher applicable screening level provided for in (1)(d) or (1)(e). The department's use of these screening levels for purposes of ARM 17.55.108(1) does not establish these levels as cleanup standards.
(5) An exceedance of a screening level alone is not sufficient for the department to initiate condemnation proceedings under 75-10-720, MCA.