Wyoming Administrative Code
Agency 020 - Environmental Quality, Dept. of
Sub-Agency 0009 - Solid Waste Management
Chapter 2 - MUNICIPAL SOLID WASTE LANDFILL REGULATIONS
Section 2-9 - Monitoring Standards

(1.) Site-specific field measurements, and information about the specific wastes to be disposed at the facility or unit; and

(2.) Contaminant fate and transport predictions which maximize contaminant migration and consider impacts on human health and the environment.

(1.) Number, spacing, and orientation of the individual waste units;

(2.) Hydrologic setting;

(3.) Site history and design; and

(4.) Type of waste accepted at the individual waste units.

(1.) Sample collection;

(2.) Sample preservation and shipment;

(3.) Analytical procedures;

(4.) Chain of custody control; and

(5.) Quality assurance and quality control.

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

(2.) An analysis of variance based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent;

(3.) A tolerance or prediction interval procedure in which an interval for each distribution of the background data, and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit;

(4.) A control chart approach that gives control limits for each constituent; or

(5.) Another statistical method approved by the Administrator.

(1.) The method shall be appropriate for the distribution of chemical parameters or constituents. If the distribution is not normal, then the data should be transformed or a distribution-free theory test should be used. If the distributions for different constituents differ, more than one statistical method may be needed;

(2.) If an individual well comparison procedure is used to compare an individual compliance well constituent concentration with background constituent concentrations or a groundwater protection standard, the test shall be done at a Type I error level no less than 0.01 for each testing period. 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. This performance standard does not apply to tolerance intervals, prediction intervals, or control charts;

(3.) If a control chart approach is used to evaluate groundwater monitoring data, the specific type of control chart and its associated parameter values must be approved by the Administrator;

(4.) If a tolerance interval or a prediction interval is used to evaluate groundwater monitoring data, the levels of confidence and, for tolerance intervals, the percentage of the population that the interval must contain, shall be approved by the Administrator;

(5.) Any data reported as below detection limits shall be entered into the statistical analysis as a value equal to one-half the practical quantitation limit (PQL) for the constituent unless the Administrator approves alternate statistical procedures. The PQL shall be the lowest concentration level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions that are available to the facility. A statistical evaluation is not necessary when all concentrations for a constituent are reported below the PQL. Samples reported with estimated concentrations shall be treated as valid measurements for statistical purposes; and

(6.) If approved by the Administrator, the statistical method may include procedures to adjust data to account for seasonal and spatial variability, as well as temporal correlation.

(1.) The owner or operator must compare the groundwater quality of each parameter or constituent at each monitoring well using the approved statistical method; and

(2.) Within thirty (30) days after completing sampling and analysis, unless an alternate time frame is approved by the administrator, the owner or operator must determine whether there has been a statistically significant increase over background at each monitoring well.

(1.) Deletes a constituent because the owner or operator shows that it is not likely to be contained in or derived from the waste disposed at the facility or unit;

(2.) Establishes an alternate list of inorganic indicator parameters in lieu of some or all of the heavy metals, if the alternative parameters provide a reliable indication of inorganic releases from the facility or unit, considering the following factors:

(3.) Determines that a different, but no less frequent than annual, monitoring schedule is appropriate, considering the following factors:

(1.) Notify the Administrator in a written report with supporting documentation and place a copy of the report in the facility operating record within fourteen (14) days and start assessment monitoring within ninety (90) days; or

(2.) Demonstrate to the Administrator in writing that the statistically significant increase over background is not due to the solid waste disposal facility or unit, but that the difference is due to another source of pollution, error in sampling, analysis or statistical evaluation, or natural variation in groundwater quality. The owner or operator shall prepare a report documenting this demonstration, and following approval by the Administrator, place the report in the operating record for the facility. If the report is approved, the owner or operator shall continue detection monitoring. If, after ninety (90) days, a successful demonstration is not made, the owner or operator must initiate an assessment monitoring program.

(1.) Lithology of the aquifer and unsaturated zone;

(2.) Hydraulic conductivity of the aquifer and unsaturated zone;

(3.) Groundwater flow rates;

(4.) Minimum distance between the facility or unit and the downgradient monitor well(s);

(5.) Classification of the aquifer under Chapter 8 of the Water Quality Rules and Regulations; and

(6.) Nature (fate and transport) of any constituents detected under assessment monitoring.

(1.) Within fourteen (14) days, notify the Administrator in a written report and place a copy of the report in the operating record identifying the Appendix B constituents that have been detected;

(2.) Within ninety (90) days, and on at least a semiannual basis thereafter, resample all wells, conduct analyses for all constituents required under detection monitoring of this section), and for all Appendix B constituents which have been detected under assessment monitoring , and record their concentrations in the operating record. At least one (1) sample must be collected from each well during each sampling event under this paragraph. The Administrator may approve an alternate sampling frequency, no less than annual, considering the factors in paragraph (b)(i)(E)(III) of this section;

(3.) Establish background concentrations for any constituents detected for the first time; and

(4.) Request in writing that the Administrator establish groundwater protection standards for all constituents detected.

(1.) Characterize the nature and extent of the release by installing additional monitor wells as necessary;

(2.) Install at least one (1) additional monitor well at the facility boundary downgradient of the release and sample the well in accord with paragraph (b)(i)(E)(IV)(2.) of this section;

(3.) Notify all persons who own or reside on the land that directly overlies any part of the plume of contamination, if that plume has migrated off-site; and

(4.) Initiate an assessment of corrective measures within ninety (90) days; or

(5.) Demonstrate to the Administrator in writing that the contamination was caused by another source, resulted from an error in sampling, analysis or statistical evaluation, or from natural variation in groundwater quality. The owner or operator shall prepare a report documenting this demonstration, and following approval by the Administrator, place the report in the operating record. If a successful demonstration is made, the owner or operator must continue monitoring under the assessment monitoring program, or may return to detection monitoring if all Appendix B constituents are at or below background. Until a successful demonstration is made, the owner or operator must comply with paragraph (b)(i)(E)(VII) of this section including initiating an assessment of corrective measures under Section 14 of this chapter.

(1.) For constituents where a maximum contaminant level (MCL) has been promulgated, the MCL for that constituent;

(2.) For constituents for which MCLs have not been promulgated, the background concentration; or

(3.) For constituents for which the background level is higher than the MCL or health-based levels, the background concentration.

(1.) Notify the Administrator in a written report with supporting documentation and place a copy of the report in the operating record within fourteen (14) days of the finding of statistical significance.

(2.) Request that the Administrator classify groundwater according to Wyoming Water Quality Rules and Regulations and establish groundwater protection standards for applicable Appendix C constituents.

(1.) Unless the owner or operator demonstrates that the statistically significant increase was caused by another source, resulted from an error in sampling, analysis, or statistical evaluation, or from natural variation in groundwater quality, the Administrator may require the owner or operator to characterize the nature and extent of the release.

(2.) The owner or operator may be required to conduct an assessment of corrective measures and institute corrective actions approved by the Administrator.