1. (a) Consistency of procedures.

   1. (1) The ground water monitoring program must 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 8 CAR § 60-1202(a).

   2. (2) The owner or operator must notify the Director of the Division of Environmental Quality that the sampling and analysis program documentation has been placed in the operating record and the program must include procedures and techniques for:

      1. (A) Sample collection;
      2. (B) Sample preservation and shipment;
      3. (C) Analytical procedures;
      4. (D) Chain of custody control; and
      5. (E) Quality assurance and quality control.

2. (b) Sampling and analytical methods.

   1. (1) The ground water monitoring program must include sampling and analytical methods that are appropriate for ground water sampling and that accurately measure Appendix 1 parameters in ground water samples as specified in 8 CAR § 60-1204(d).
   2. (2) Ground water samples shall not be field-filtered prior to laboratory analysis.
   3. (3) Analytical methods utilized should conform to SW-486 or the most current United States Environmental Protection Agency approved analytical method.
   4. (4) Primary drinking water standard MCLs shall be superseded by the publication of new standards from the United States Environmental Protection Agency.
3. (c) Environmental protection. The sampling procedures and frequency must be protective of human health and the environment.

4. (d) Determination of ground water flow.

   1. (1) Ground water elevations must be measured in each well immediately prior to purging each time ground water is sampled.
   2. (2) The owner or operator must determine the rate and direction of ground water flow each time ground water is sampled.
   3. (3) Ground water elevations in wells which monitor the same waste management 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.

5. (e) Background water quality.

   1. (1) The owner or operator must establish background ground water quality in each hydraulically up gradient or background well and the downgradient wells for each of the monitoring parameters or constituents required in the particular ground water monitoring program that applies to the landfill, as determined under 8 CAR § 60-1204(a) or 8 CAR § 60-1205(a) for Class 1 landfills, or as determined under 8 CAR §§ 60-523 and 60-524 for Class 3 and other facilities required to monitor ground water quality.
   2. (2) Background ground water quality may be established at wells that are not located hydraulically up gradient from the landfill if it meets the requirements of 8 CAR § 60-1202(a)(1).
   3. (3) Background ground water quality is determined through the collection of, at a minimum, four (4) independent samples from each well (background and downgradient).
   4. (4) To account for seasonal and temporal variations, each sample shall be collected quarterly unless another frequency has been approved by the director.

6. (f) Conformance with statistical procedures.

   1. (1) The number of samples collected to establish ground water quality data must be consistent with the appropriate statistical procedures determined pursuant to subsection (g) of this section.

   2. (2) The sampling procedures shall be those specified under:

      1. (A) 8 CAR § 60-1204(b) for detection monitoring;
      2. (B) 8 CAR § 60-1205(b) and (d) for assessment monitoring; and
      3. (C) 8 CAR § 60-1206(b) for corrective action.

7. (g) Statistical method selection.

   1. (1)

      1. (A) The owner or operator must specify in the operating record one (1) of the following statistical methods to be used in evaluating ground water monitoring data for each constituent.
      2. (B) The statistical test chosen shall be conducted separately for each constituent in each well.

   2. (2)

      1. (A) A parametric analysis of variance (ANOVA) followed by multiple comparisons procedures to identify statistically significant evidence of contamination.
      2. (B) The method must include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent.

   3. (3)

      1. (A) An analysis of variance (ANOVA) based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination.
      2. (B) The method must include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent.
   4. (4) 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.
   5. (5) A control chart approach that gives control limits for each constituent.

   6. (6)

      1. (A) Another statistical test method that meets the performance standards of subsection (h) of this section.
      2. (B) The owner or operator must place a justification for this alternative in the operating record and notify the director of the use of this alternative test.
      3. (C) The justification must demonstrate that the alternative method meets the performance standards of subsection (h) of this section.
   7. (7) In the event recommended United States Environmental Protection Agency guidance changes, the statistical method selection should follow current United States Environmental Protection Agency guidance directives.
   8. (8) The most current statistical methods as recommended in United States Environmental Protection Agency guidance publications.

8. (h) Statistical method selection criteria. Any statistical method chosen under subsection (g) of this section shall comply with the following performance standards, as appropriate:

   1. (1)

      1. (A) The statistical method used to evaluate ground water monitoring data shall be appropriate for the distribution of chemical parameters or hazardous constituents.
      2. (B) If the distribution of the chemical parameters or 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.
      3. (C) If the distributions for the constituents differ, more than one (1) statistical method may be needed;

   2. (2)

      1. (A) 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 one-hundredths (0.01) for each testing period.
      2. (B) If a multiple comparisons procedure is used, the Type I experiment wise error rate for each testing period shall be no less than five-hundredths (0.05), however, the Type I error of no less than one-hundredths (0.01) for individual well comparisons must be maintained.
      3. (C) This performance standard does not apply to tolerance intervals, prediction intervals, or control charts;

   3. (3)

      1. (A) 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.
      2. (B) The parameters shall be determined after considering the:

9. (i) Number of samples in the background data base;

   1. (ii) Data distribution; and

      1. (iii) Range of the concentration values for each constituent of concern;

   2. (4)

      1. (A) If a tolerance interval or a prediction interval is used to evaluate ground water monitoring data, the levels of confidence and, for tolerance intervals, the percentage of the population that the interval must contain, shall be protective of human health and the environment.

      2. (B) These parameters shall be determined after considering the:

         1. (i) Number of samples in the background data base;
         2. (ii) Data distribution; and
         3. (iii) Range of the concentration values for each constituent of concern;

   3. (5)

      1. (A) The statistical method shall account for data below the limit of detection, i.e., the method detection limit (MDL) as specified in 8 CAR § 60-1204(d), with one (1) or more statistical procedures that are protective of human health and the environment.
      2. (B) A facility should report values between the method detection limit (MDL) and practical quantitation limit (PQL) but only utilize values reported above the PQL in the statistics.
      3. (C) Any PQL or MDL that is used in the statistical method shall be the lowest concentration level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions using current laboratory standards.
      4. (D) All verifiable, positive detections above the constituent practical quantitation limit (PQL) must be reported and included in the statistical analysis; and

   4. (6) 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.

      1. (i) Determination of statistically significant increase or decrease.

   5. (1)

      1. (A) The owner or operator must determine whether or not there is a statistically significant increase or decrease over background values for pH.
      2. (B) The owner or operator must determine whether or not there is a statistically significant increase for each parameter or constituent required in the particular ground water monitoring program that applies to the landfill, as determined under 8 CAR § 60-1204(a) or 8 CAR § 60-1205(a).
   6. (2) In determining whether a statistically significant increase has occurred, the owner or operator must compare the ground water quality of each parameter or constituent at each monitoring well designated pursuant to 8 CAR § 60-1202(a)(2) to the background value of that constituent, according to the statistical procedures and performance standards specified under subsections (g) and (h) of this section.

   7. (3)

      1. (A) Within a reasonable period of time after completing sampling and analysis, the owner or operator must determine whether there has been a statistically significant increase compared to the background at each monitoring well.
      2. (B) The owner or operator shall notify the Division of Environmental Quality in writing of statistically significant increases in detection monitoring water chemistry parameters.

10. (j) Sampling and analysis plans.

    1. (1) Owners or operators shall develop and implement a Division of Environmental Quality-approved site-specific written sampling and analysis plan.
    2. (2) The sampling and analysis plan and all reports to the Division of Environmental Quality required under the sampling and analysis plan shall be certified by a qualified ground water scientist.

    3. (3) The sampling and analysis plan must include the following elements:

       1. (A) Detailed procedures used to collect reliable samples from the ground water monitoring system including:

          1. (i) Equipment to be used to maintain a clean working area;
          2. (ii) Equipment utilized to purge wells and to extract samples from wells;
          3. (iii) Purge volumes and methods utilized to calculate purge volumes;
          4. (iv) Sample extraction procedures and containerization of samples;
          5. (v) Sample container labeling; and
          6. (vi) Sample chain of custody procedures;
       2. (B) Laboratory analytical procedures;
       3. (C) Sample collection and laboratory quality assurance/quality control procedures;
       4. (D) Ground water analytical data submittal procedures which shall include provisions for the direct submittal of all analytical results from the contract or independent third party laboratory to the Division of Environmental Quality;

       5. (E)

          1. (i) A method for statistically evaluating ground water analytical data for significant changes must be selected.
          2. (ii) The method must be tailored to fit the hydrogeology of the site.
          3. (iii) For data quality assurance purposes, the statistical evaluation should be performed by a third party independent from the contract laboratory analyzing the ground water;
       6. (F) Division of Environmental Quality notification procedures in the event that statistically significant increases in analytes are noted; and
       7. (G) A contingency plan must be developed which outlines the procedures to initiate an assessment monitoring program once confirmed statistically significant increases in analyte concentrations have been detected and the Division of Solid Waste Management has been notified.

11. (k) Ground water monitor reporting.

    1. (1)

       1. (A) The owner or operator of a Class 1 or 3 facility shall submit to the director a Ground Water Monitoring Report prepared and certified by a qualified ground water scientist which contains a determination of the direction of ground water flow across the site based on water level measurements taken during the most recent sampling event at the facility and potentiometric surface map showing the locations of the monitor wells at the site.
       2. (B) The permittee shall also provide a determination of the rate of ground water flow across the site.
    2. (2) The facility must, in accordance with the approved sampling and analysis plan, determine if a statistically significant increase has occurred for any constituent detected above established background concentrations at the facility, based on the analytical results from the most recent sampling event.
    3. (3) The facility must provide appropriate documentation of SSIs in the GWMR.
    4. (4) The operator shall analyze the monitoring data collected and provide a discussion in the GWMR on the findings and conclusions concerning ground water quality at the facility.
    5. (5) If an SSI is confirmed, the permittee must notify the Division of Environmental Quality in accordance with 8 CAR § 60-1204(c).
    6. (6) The GWMR shall be submitted to the Division of Solid Waste Management within ninety (90) days from the date of the last recorded sampling event.

Codification Notes: “MCL” means maximum contaminant level. "GWMR" means Ground Water Monitoring Report.