NAC444.7492. Establishment of standard for protection of groundwater.

     1. The Administrator shall establish a standard for the protection of groundwater for each constituent listed in Appendix II detected in the groundwater as follows:

     (a) For a constituent for which a maximum contaminant level has been set forth 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 November 8, 1993, the maximum contaminant level for that constituent.

     (b) For a constituent for which a maximum contaminant level has not been adopted, a level equal to:

          (1) The background concentration of the constituent; or

          (2) An appropriate level that is based on the protection of public health and safety and complies with the following requirements:

               (I) The level must be established in compliance with state and federal guidelines for assessing the health risks of environmental pollutants;

               (II) The level must be based on scientific studies conducted in accordance with the Toxic Substances Control Act Good Laboratory Practice Standards, 40 C.F.R. Part 792, as those standards exist on March 1, 1994, or equivalent studies;

               (III) For carcinogens, the level must represent a concentration of the constituent that is associated with an excess risk of cancer caused by a continuous lifetime exposure which is within a range of 1 X 10^-4 to 1 X 10^-6, inclusive; and

               (IV) For systemic toxicants, the level must represent a concentration to which a human being could be exposed on a daily basis without an appreciable risk of deleterious effects during the course of his or her lifetime. As used in this sub-subparagraph, “systemic toxicant” includes toxic chemicals that cause deleterious effects other than cancer or a mutation.

     (c) For a constituent for which the background level is higher than the maximum contaminant level set forth in paragraph (a), the background concentration of the constituent.

     2. In establishing standards pursuant to paragraph (b) of subsection 1, the Administrator may consider:

     (a) Multiple contaminants in the groundwater;

     (b) Potential threats to sensitive areas of the environment; and

     (c) Other threats specific to that site or potential threats to groundwater.

     (Added to NAC by Environmental Comm’n, eff. 11-8-93; A 3-1-94)