The department shall calculate Tier 1 action levels shown in Table 1 in this section based on the petroleum contamination in soil leaching to the groundwater pathway, with an excess lifetime cancer risk not exceeding 1:100,000 and a chronic noncancer risk not exceeding a hazard index of one. The department assumes there are receptors actually or potentially ingesting groundwater at the point of maximum soil contamination.

Table 1 is as follows:

TIER 1 ACTION LEVELS FOR SOILS AT PETROLEUM RELEASE SITES

Tier 1 Action Level

(ppm = parts per million)

0.2 ppm

Toluene

15 ppm

Ethylbenzene

10 ppm

Xylene

300 ppm

Napthalene

25 ppm

Source: 22 SDR 86, effective December 18, 1995; transferred from § 74:03:33:07, July 1, 1996.

General Authority: SDCL 34A-2-93 , 34A-2-99 , 34A-2-101 , 34A-12-7.

Law Implemented: SDCL 34A-2-99 , 34A-2-101 , 34A-12-10.