NAC445A.22735. Contamination of groundwater: Establishment of action levels.

     1. For the purposes of NAC 445A.22725, 445A.2273 and 445A.2274, the action level for groundwater must be established at the following levels:

     (a) The presence of 1/2 inch or more of a petroleum substance that is free-floating on the surface of the water of an aquifer, using a measurement accuracy of .01 feet.

     (b) The presence of a hazardous substance, hazardous waste or a regulated substance in groundwater at a level of concentration equal to the maximum contaminant level for that substance or waste established pursuant to the Safe Drinking Water Act, 42 U.S.C. §§ 300f et seq., and 40 C.F.R. Part 141, as those sections existed on October 3, 1996.

     (c) A level of concentration equal to the background concentration of a hazardous substance, hazardous waste or a regulated substance, if that level of concentration is greater than the maximum contaminant level established pursuant to paragraph (b).

     (d) If a maximum contaminant level has not been established for a hazardous substance, hazardous waste or a regulated substance, a level of concentration equal to:

          (1) The background concentration of the waste or substance; or

          (2) An appropriate level of concentration that is based on the protection of public health and safety and the environment. The appropriate level of concentration must be determined by the Division using the Integrated Risk Information System, adopted by reference in NAC 445A.2272, or an equivalent method approved by the Division.

     2. In establishing an action level pursuant to subsection 1, the Division may consider:

     (a) The presence of more than one hazardous substance, hazardous waste or regulated substance in the groundwater;

     (b) Any potential threat the contamination may pose to sensitive areas of the environment; and

     (c) Any other threat or potential threat to groundwater that is specifically related to the site.

     3. If more than one action level for groundwater may be established using the criteria set forth in subsection 1, the most restrictive action level must be used.

     4. The Safe Drinking Water Act, 42 U.S.C. §§ 300f et seq., and 40 C.F.R. Part 141, as those sections existed on October 3, 1996, are hereby adopted by reference. A copy of those sections may be obtained by mail from the Superintendent of Documents, U.S. Government Printing Office, P.O. Box 979050, St. Louis, Missouri 63197-9000, or by toll-free telephone at [phone], at a cost of $30.

     (Added to NAC by Environmental Comm’n, eff. 10-3-96)