Section 132-7-003 - Ground Water Sampling and Analysis Requirements003.01 The ground water monitoring plan shall include consistent sampling and analysis procedures that are designed to ensure monitoring results that provide an accurate representation of ground water quality at the background and downgradient wells installed in compliance with 002 of this chapter. 003.01A An owner or operator shall notify the Department that the sampling and analysis plan has been placed in the operating record.003.01B The plan shall include procedures and techniques for: 003.01B1 Sample collection;003.01B2 Sample preservation and shipment;003.01B3 Analytical procedures;003.01B4 Chain of custody control; and003.01B5 Quality assurance and quality control.003.02 The ground water monitoring plan shall include sampling and analytical methods that are appropriate for ground water sampling and that accurately measure hazardous constituents and other monitoring parameters in ground water samples.003.03 The sampling procedures and frequency shall be protective of human health and the environment.003.04 Each time ground water is sampled, ground water elevations shall be measured in each well immediately prior to purging.003.04A An owner or operator shall determine the rate and direction of ground water flow each time ground water is sampled.003.04B Ground water elevations in wells which monitor the same solid waste disposal area must be measured within a period of time short enough to avoid temporal variations in ground water flow which could preclude accurate determination of ground water flow rate and direction.003.05 An owner or operator shall establish background ground water quality in a hydraulically upgradient or background well(s) for each of the monitoring parameters of constituents required in the particular ground water monitoring program that applies to the solid waste disposal area, as determined by 004.01 or 005.01 of this chapter. 003.05A Background ground water quality may be established at wells that are not located hydraulically upgradient from the solid waste disposal area if they meet the requirements of 002.01A of this chapter.003.06 The number of samples collected to establish ground water quality data shall be consistent with the appropriate statistical procedures determined pursuant to 003.07 of this chapter.003.06A The sampling procedures shall be those specified under 004.02 of this chapter for detection monitoring, 005.02 and 005.04 of this chapter for assessment monitoring, and 006 of this chapter for remedial actions.003.07 An owner or operator shall specify in the operating record one of the following statistical methods to be used in evaluating ground water monitoring data for each constituent. The statistical test chosen shall be conducted separately for each constituent in each well.003.07A A parametric analysis of variance (ANOVA) followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method shall include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent.003.07B An analysis of variance (ANOVA) based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method shall include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent.003.07C A tolerance or prediction interval procedure in which an interval for each constituent is established from the distribution of the background data, and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit.003.07D A control chart approach that gives control limits for each constituent.003.07E Another statistical test method that meets the performance standards of 003.08 of this chapter. 003.07E1 An owner or operator shall place a justification for this alternative in the operating record and notify the Department of the use of this alternative test.003.07E2 The justification shall demonstrate that the alternative method meets the performance standards of 003.08 of this chapter.003.08 Any statistical method chosen under 003.07 of this chapter shall comply with the following performance standards, as appropriate: 003.08A The statistical method used to evaluate ground water monitoring data shall be appropriate for the distribution of chemical parameters or hazardous constituents. 003.08A1 If the distribution of the chemical parameters of hazardous constituents is shown by the owner or operator to be inappropriate for a normal theory test, then the data should be transformed or a distribution-free theory test should be used. If the distributions for the constituents differ, more than one statistical method may be needed.003.08B If an individual well comparison procedure is used to compare an individual compliance well constituent concentration with background constituent concentrations or a ground water protection standard, the test shall be done at a Type I error level no less than 0.01 for each testing period. 003.08B1 If a multiple comparisons procedure is used, the Type I experiment wise error rate for each testing period shall be no less than 0.05; however, the Type I error of no less than 0.01 for individual well comparisons must be maintained.003.08B2 This performance standard does not apply to tolerance levels, prediction intervals, or control charts.003.08C If a control chart approach is used to evaluate ground water monitoring data, the specific type of control chart and its associated parameter values shall be protective of human health and the environment. 003.08C1 The parameters shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.003.08D If a tolerance interval or a predictional interval is used to evaluate ground water monitoring data, the levels of confidence and, for tolerance levels, the percentage of the population that the interval must contain, shall be protective of human health and the environment. 003.08D1 These parameters shall be determined after considering the number of samples in the background data base, the data distribution, and the range of the concentration values for each constituent of concern.003.08E The statistical method shall account for data below the limit of detection with one or more statistical procedures that are protective of human health and the environment. 003.08E1 Any practical quantitation limit that is used in the statistical method shall be the lowest concentration level that can reliably be achieved within the specified limits of precision and accuracy during routine laboratory operating conditions that are available to the facility.003.08F If necessary, the statistical method shall include procedures to control or correct for seasonal and spatial variability as well as temporal correlation in the data.003.09 An owner or operator shall determine whether there is a statistically significant increase over background values for each parameter or constituent required in the particular ground water monitoring program that applies to the solid waste disposal area, as determined under 004.01 of this chapter.003.09A In determining whether a statistically significant increase has occurred, an owner or operator shall compare the ground water quality of each parameter or constituent at each monitoring well designated pursuant to 002.01B to the background value of that constituent, according to the statistical procedures and the performance standards specified in 003.07 and 003.08 of this chapter.003.09B Within thirty (30) days of completing sampling and analysis, the owner or operator shall determine whether there has been a statistically significant increase over background at each monitoring well.132 Neb. Admin. Code, ch. 7, § 003