NR 720.08(1)(1) General. If a responsible party selects this option, performance standards shall be established and maintained so that the residual contaminants in the soil do not pose a threat to public health, safety, or welfare or the environment.

NR 720.08 NoteNote: Guidance document RR-528 indicates that it may not be necessary to determine numeric residual contaminant levels for contaminants as long as all contaminant pathways for all contaminants of concern are addressed by the remedial action, the extent of contamination is fully defined, the remedy remains in place, is maintained as appropriate and remains effective. For example, if a cover is placed that addresses all pathways for the contaminated soil, then it isn’t necessary to determine the numeric residual contaminant levels for as long as the cover adequately addresses the pathway and remains protective. It may be necessary to determine residual contaminant levels in the future if the remedy is changed or replaced.

NR 720.08(2)(2) Protection of groundwater. Acceptable performance standard options to address the soil to groundwater pathway may include any of, or any combination of, the following:

NR 720.08(2)(a)(a) Placement of a permanent engineering control such as a cap or cover to limit infiltration and thereby minimizing the leaching of soil contaminants to groundwater that is constructed and maintained until the threat to groundwater no longer exists.

NR 720.08 NoteNote: As explained in more detail in guidance document RR-528, if there is no threat to groundwater from soil contamination, a soil remedy is not necessary. The lack of groundwater contamination may not always be sufficient to establish there is not threat to the groundwater pathway. An analysis to determine whether sufficient time has passed for the soil contamination to have reached the locations where groundwater is being monitored may be necessary. The factors that may need to be considered include: the age of the contaminant release, type of contaminants, geologic setting, depth to groundwater, and the proximity of the monitoring wells to the source of contamination.

NR 720.08(3)(3) Protection from direct contact. Acceptable performance standard options to address the direct contact pathway may include either of, or a combination of, the following:

NR 720.08(3)(a)(a) Placement of a permanent engineering control such as a cap or cover that is constructed and maintained until the direct contact threat no longer exists.

NR 720.10(1)(1) General. If a responsible party selects this option, residual contaminant levels for soil based on protection of groundwater shall be developed using the enforcement standards established in ch. NR 140 or using procedures consistent with the methodology in ss. 160.13 and 160.15, Stats., and the criteria in s. NR 722.09 (2) (b) 2. when there is no enforcement standard as the target concentrations in groundwater. If the department of health has not developed a recommended enforcement standard and a federal maximum contaminant level exists, that value may be used for calculating a soil residual contaminant level.

NR 720.10 NoteNote: In developing a residual contaminant level, any relevant information may be considered, including public welfare concerns for groundwater, such as taste and odor, and drinking water health advisory levels.

NR 720.10(2)(2) Methods. Responsible parties shall use one or more of the methods listed in this section based on scientifically valid procedures that are subject to department review and approval and site-specific geological, physical and chemical conditions to establish residual contaminant levels:

NR 720.10(2)(c)(c) Any other appropriate method approved by the department for that specific site or facility, or other appropriate method suggested in department guidance.

NR 720.10 NoteNote: Guidance document RR-890 provides detailed instructions on one method the department considers scientifically valid for purposes of calculating site specific residual contaminant levels that are protective of groundwater quality. A table of residual contaminant levels that are calculated using the standard default exposure assumptions can be found at: http://dnr.wi.gov/topic/Brownfields/professionals.html#tabx2.

NR 720.12NR 720.12 Procedures for determining residual contaminant levels based on protection of human health from direct contact with contaminated soil.

NR 720.12(1)(1) General. If a responsible party selects this option, residual contaminant levels for soil based on protection of human health from direct contact shall be developed using the following criteria:

NR 720.12(1)(b)(b) The cumulative excess cancer risk will not exceed 1x10-5 and the hazard index for non-carcinogens will not exceed one for the site or facility.

NR 720.12(1)(c)(c) Risks for carcinogens and hazard quotients for non-carcinogens are presumed to be additive within each category, unless there is specific information that demonstrates that an alternative approach is more appropriate.

NR 720.12(1)(d)(d) If toxicological values for both carcinogenic and non-carcinogenic end points exist for a substance, both shall be evaluated and the method that generates the lowest residual contaminant level shall be used for the site or facility.

NR 720.12(2)(2) Methods and procedures. Responsible parties shall determine a residual contaminant level to protect public health from direct contact with soil contamination using scientifically valid procedures and toxicological values approved by the department and the default exposure assumptions identified in sub. (3) or alternative assumptions specifically approved by the department in writing.

NR 720.12 NoteNote: The department will generally consider toxicological values in the following order: U.S. EPA’s Integrated Risk Information System (IRIS); U.S. EPA’s Provisional Peer Reviewed Toxicity Values (PPRTV); Agency for Toxic Substances and Disease Registry (ATSDR); California EPA (Cal EPA); U.S. EPA’s Health Effects Assessment Summary Tables (HEAST); other pertinent toxicological information.