Section NR 720.07 - General requirements when establishing soil cleanup standards applicable to a site or facility(1) GENERAL. (a) Responsible parties shall use information from the sources listed in s. NR 720.05(1) to determine the residual contaminant levels or performance standards for each exposure or migration pathway of concern for each soil contaminant of concern at a site or facility in accordance with this chapter.(b) In addition to meeting the requirements of par. (c), responsible parties shall establish the soil cleanup standard for each soil contaminant of concern at the site or facility as one of the following:1. The residual contaminant level of each contaminant in soil which is the lowest concentration from among the following as applicable: the ceiling limit concentration, the soil saturation concentration if the contaminant is a volatile, a land use specific direct contact level, a groundwater quality protective level, a concentration calculated for a pathway of concern set forth in s. NR 720.13 all of which are determined in accordance with the requirements of this chapter. Note: For a single contaminant, a numeric land use specific residual contaminant level is determined based on aggregate exposure through incidental ingestion of soil, inhalation of soil vapors and particulates, and dermal contact with soil. When more than one contaminant is present, the residual contaminant level is determined based on cumulative exposure and may have to be adjusted downward so that the cumulative risk does not exceed an excess cancer risk of 1-in-100,000 or a hazard index of 1 for non-carcinogens.
2. A performance standard determined in accordance with s. NR 720.08.(c) In addition to meeting the requirements of par. (b), a soil cleanup standard developed under this chapter shall comply with all the following requirements: 1. Residual soil contamination at the site or facility may not adversely affect surface water.2. Residual soil contamination at the site or facility may not adversely affect a sensitive environment.3. Residual soil contamination at the site or facility may not concentrate through plant uptake and adversely affect the food chain.4. Residual soil contamination at the site or facility may not result in vapor concentrations reaching a substance's lower explosive limit.(2)COMPLIANCE WITH SOIL CLEANUP STANDARDS. (a) Contaminant concentrations in soil samples shall be determined using a department-approved and appropriate analytical method and reported on a dry weight basis. An appropriate analytical method shall have limits of detection or limits of quantitation, or both, at or below soil cleanup standards where possible. Responsible parties shall report the limit of detection and the limit of quantitation with sample results. The department may require that supporting documentation for the reported limit of detection and limit of quantitation be submitted(b) Unless an alternative approach for determining standards exceedances is approved by the department, if a soil contaminant concentration in a sample exceeds the soil cleanup standard at or above the limit of quantitation for that soil contaminant, the soil cleanup standard shall be considered to have been exceeded. Note: When evaluating the direct contact pathways, it may be possible to average measured soil sample concentrations to determine whether the calculated residual contaminant level has been exceeded or not. If averaging of soil concentrations is being considered, the department recommends seeking department approval of the proposed sampling plan and analysis methodology as soon as possible, but prior to submitting a case closure request in order to avoid delays and other potential problems.
Note: Averaging soil concentrations is not appropriate as the sole method for addressing sites with areas of significant soil contamination.
(c) If a soil cleanup standard for a soil contaminant is between the limit of detection and the limit of quantitation, the soil cleanup standard shall be considered to be exceeded if the soil contaminant concentration is reported at or above the limit of quantitation.(d) The following applies when a soil cleanup standard for a soil contaminant is below the limit of detection: 1. If a soil contaminant is not detected in a sample, the soil cleanup standard shall not be considered to have been exceeded.2. If a soil contaminant is reported above the limit of detection but below the limit of quantitation, the responsible party may accept the results and the soil cleanup standard shall be considered to have been exceeded, or the responsible party may choose to have the soil sample reanalyzed by the use of an appropriate analytical method. If the soil contaminant is confirmed to be present between the limit of detection and the limit of quantitation, the soil cleanup standard shall be considered to have been exceeded. If the soil contaminant is not detected upon reanalysis of the soil sample, the soil cleanup standard shall not be considered to have been exceeded.(3)BACKGROUND. If the background concentration for a substance in soil at a site or facility is higher than the residual contaminant level for that substance determined using the procedures in this section, the background concentration in soil may be used as the residual contaminant level for that substance. The background concentration for a substance in soil shall be determined using a department-approved and appropriate method.Wis. Admin. Code Department of Natural Resources NR 720.07
Cr. Register, March, 1995, No. 471, eff. 4-1-95; CR 12-023: am. (title), (1) (a) to (c), cr. (1) (c) 4., am. (2) (b), (d) 2., cr. (3) Register October 2013 No. 694, eff. 11-1-13. Naturally occurring background concentrations of arsenic in soil, for example, may be higher than the calculated residual contaminant level for arsenic. In such instances, the naturally occurring background concentration could be used as the soil cleanup level.