NAC444.749. Program for assessment monitoring.

     1. If a statistically significant increase over background has been detected for one or more of the constituents listed in Appendix I or the list of alternative parameters established pursuant to NAC 444.7487, an owner or operator shall establish a program for assessment monitoring.

     2. Except as otherwise provided in subsection 3, within 90 days after initiating a program for assessment monitoring, and annually thereafter, the owner or operator shall sample and analyze the groundwater for all constituents identified in Appendix II. At least one sample from each downgradient well must be collected and analyzed during each sampling. For any constituent detected in the downgradient wells as a result of this analysis, at least four independent samples from each background and downgradient well must be collected and analyzed to establish background for the constituents. The solid waste management authority may specify an appropriate subset of wells to be sampled and analyzed for constituents listed in Appendix II during assessment monitoring. The solid waste management authority may delete any of the parameters for monitoring constituents listed in Appendix II for a municipal solid waste landfill unit if it is shown that the deleted constituents are not reasonably expected to be in or derived from the waste contained in the unit.

     3. The solid waste management authority may specify an appropriate alternative schedule for monitoring all constituents listed in Appendix II. The alternative schedule must be based on the:

     (a) Lithology of the aquifer and unsaturated zone;

     (b) Hydraulic conductivity of the aquifer and unsaturated zone;

     (c) Rate of flow of groundwater;

     (d) Minimum distance between the upgradient edge of the municipal solid waste landfill unit and downgradient monitoring well screen;

     (e) Resource value of the aquifer; and

     (f) Nature, fate and transportation of any constituents detected in accordance with this section.

     4. After obtaining the results from the initial or subsequent samplings pursuant to subsection 2 or 3, the owner or operator shall:

     (a) Within 14 days, place a notice in the operating records of the disposal site identifying the constituents listed in Appendix II which have been detected and submit the sampling results to the solid waste management authority.

     (b) Within 90 days, and on at least a semiannual basis thereafter:

          (1) Resample all wells specified by NAC 444.7483;

          (2) Conduct analyses for all constituents listed in Appendix I or the list of alternative parameters established pursuant to NAC 444.7487, and for those constituents in Appendix II which are detected as a result of sampling pursuant to subsection 2 or 3; and

          (3) Record their concentrations in the operating records for the disposal site.

Ê At least one sample from each background and downgradient well must be collected and analyzed during the samplings. The solid waste management authority may specify an alternative schedule for monitoring the constituents referred to in this section. The alternative schedule for constituents listed in Appendix I or the list of alternative parameters established pursuant to NAC 444.7487 may not require monitoring not less than annually. The alternative schedule must be based on the factors specified in subsection 3.

     (c) Establish background concentrations for any constituents detected pursuant to paragraph (b) or subsection 2 or 3.

     (Added to NAC by Environmental Comm’n, eff. 11-8-93)