132 Neb. Admin. Code, ch. 7, § 005

Current through September 17, 2024

Section 132-7-005 - Assessment Monitoring Program

005.01 Assessment monitoring is required whenever a statistically significant increase over background has been detected for one or more of the constituents listed in Appendix I or in the alternative list described in 004.01C of this chapter.

005.02 Within ninety (90) days of triggering an assessment monitoring program, and annually thereafter, an owner or operator shall sample and analyze the ground water for all constituents identified in Appendix II, which is attached to these regulations and incorporated herein by this reference.

005.02A A minimum of one sample from each downgradient well shall be collected and analyzed during each sampling event.

005.02B For any constituent detected in the downgradient wells as a result of the complete Appendix II analysis, a minimum of four (4) independent samples must be collected and analyzed to establish background for the constituents.

005.02C The Department may specify an appropriate subset of wells to be sampled and analyzed for Appendix II constituents during assessment monitoring.

005.02D The Department may delete any of the Appendix II monitoring parameters if an owner or operator can show that the removed constituents are not reasonably expected to be in or derived from the waste contained in the solid waste disposal area.

005.03 Upon request by an owner or operator, the Department may specify an appropriate alternative frequency for repeated sampling and analysis for the full set of Appendix II constituents required by 005.02 of this chapter during the active life including closure and post-closure care of the solid waste disposal area based on a consideration of the following factors:

005.03A Lithology of the aquifer and unsaturated zone;

005.03B Hydraulic conductivity of the aquifer and unsaturated zone;

005.03C Ground water flow rates;

005.03D Minimum distance between upgradient edge of the solid waste disposal area and downgradient monitoring well screen (minimum distance of travel);

005.03E Resource value of the aquifer; and

005.03F Nature (fate and transport) of any constituents detected in response to this chapter.

005.04 After obtaining the results from the initial or subsequent sampling events required in 005.02 of this chapter, an owner or operator shall:

005.04A Within fourteen (14) days, place a notice in the operating record identifying the Appendix II constituents that have been detected and notify the Department that this notice has been placed in the operating record;

005.04B Within ninety (90) days, and on at least a semiannual basis thereafter, resample all wells specified by 002.01 of this chapter; and conduct analyses for all constituents in Appendix I or in the alternative list in 004.01C, and for those constituents in Appendix II that are detected in response to 005.02 of this chapter, and record their concentrations in the facility's operating record.

005.04B1 At least one sample from each well (background and downgradient) shall be collected and analyzed during these sampling events.

005.04B2 Upon request by an owner or operator, the Department may specify an alternative monitoring frequency during the active life including closure and the post-closure period for the constituents referred to in 005.04B.

005.04B2(a) The alternative frequency for Appendix I constituents or the alternative list shall be no less than annual during the active life including closure.

005.04B2(b) The alternative frequency shall be based on consideration of the factors specified in 005.03 of this chapter.

005.04C Establish background concentrations for any constituents detected pursuant to 005.02 or 005.04B of this chapter; and

005.04D Establish ground water protection standards for all constituents detected pursuant to 005.02 or 005.04 of this chapter.

005.04D1 The ground water protection standards shall be established in accordance with 005.08 or 005.09 of this chapter.

005.05 If the concentrations of all Appendix II constituents are shown to be at or below background values, using the statistical procedures in 003.07, for two (2) consecutive sampling events, an owner or operator shall notify the Department of this finding and may return to detection monitoring.

005.06 If the concentrations of all Appendix II constituents are above background values, but all concentrations are below the ground water protection standards established under 005.08 or 005.09 of this chapter, using the statistical procedures in 003.07, an owner or operator shall continue assessment monitoring in accordance with this chapter.

005.07 If one or more Appendix II constituents are detected at statistically significant levels above the ground water protection standards established under 005.08 or 005.09 of this chapter in any sampling event, an owner or operator

005.07A Shall, within fourteen (14) days of this finding, place a notice in the operating record identifying the Appendix II constituents that have exceeded the ground water protection standard and notify the Department and all appropriate local government officials that the notice has been placed in the operating record;

005.07B Shall characterize the nature and extent of the release by installing additional monitoring wells as necessary;

005.07C Shall install at least one (1) additional monitoring well at the facility boundary in the direction of the contaminant migration and sample this well in accordance with 005.04B of this chapter;

005.07D Shall notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site if indicated by sampling of wells in accordance with 005.07B;

005.07E Shall initiate an assessment of remedial measures as required by 006 of this chapter within ninety (90) days; and

005.07F May demonstrate that a source other than the solid waste disposal area caused the contamination, or that the statistically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality.

005.07F1 A report documenting this demonstration shall be certified by a qualified ground water scientist and approved by the Department and be placed in the operating record.

005.07F2 If a successful demonstration is made and documented, the owner or operator shall continue monitoring pursuant to 005 of this chapter, and may return to detection monitoring if the Appendix II constituents are at or below background as specified in 005.05.

005.07F3 Until a successful demonstration is made, an owner or operator shall comply with the requirements of 005.07 of this chapter, including initiating an assessment of remedial measures.

005.08 An owner or operator shall establish a ground water protection standard for each Appendix II constituent detected in the ground water. The ground water protection standard shall be:

005.08A For constituents for which a maximum contaminant level (MCL) has been promulgated under section 1412 of the Safe Drinking Water Act, codified under 40 C.F.R. section 141, the MCL for that constituent;

005.08B For constituents for which MCLs have not been promulgated, the background concentration for the constituent established from wells in accordance with 002.01A; or

005.08C For constituents for which the background level is higher than the MCL identified under 005.08B of this chapter or health based levels identified under 005.09A, the background concentration.

005.09 The Department may establish an alternative ground water protection standard for constituents for which MCLs have not been established. These ground water protection standards shall be appropriate health based levels that satisfy the following criteria:

005.09A The level is derived in a manner consistent with EPA guidelines for assessing the health risks of environmental pollutants (51 Fed. R. 33992, 34006, 34014, 34028, Sept. 24, 1986);

005.09B The level is based on scientifically valid studies conducted in accordance with the Toxic Substances Control Act, Good Laboratory Practice Standards (40 C.F.R. sec. 792), or the equivalent;

005.09C For carcinogens, the level represents a concentration associated with an excess lifetime cancer risk level (due to continuous lifetime exposure) with the 1 x 10^-4 to 1 x 10^-6 range; and

005.09D For systemic toxicants, the level represents a concentration to which the human population (including sensitive subgroups) could be exposed to on a daily basis that is likely to be without appreciable risk of deleterious effects during a lifetime.

005.09D1 For purposes of 005.09D, systemic toxicants include toxic chemicals that cause effects other than cancer or mutation.

005.10 In establishing ground water protection standards under 005.09 of this chapter, the Department may consider the following:

005.10A Multiple contaminants in the ground water;

005.10B Exposure threats to sensitive environmental receptors; and

005.10C Other site-specific exposure or potential exposure to ground water.

132 Neb. Admin. Code, ch. 7, § 005