S.C. Code Regs. § § 61-107.19.V.E.258.53

Current through Register Vol. 48, No. 10, October 25, 2024

Section 61-107.19.V.E.258.53 - Groundwater Sampling and Analysis Requirements

a. The groundwater monitoring program shall include consistent sampling and analysis procedures that are designed to ensure monitoring results that provide an accurate representation of groundwater quality at the background and downgradient wells installed in compliance with Section258.51.a. of this Part. The permittee shall submit to the Department for review and approval, the sampling and analysis procedures and protocols to be used at the facility. After approval by the Department, documentation shall be placed in the operating record. The program shall include procedures and techniques for:

(1) Sample collection;

(2) Sample preservation and shipment;

(3) Analytical procedures;

(4) Chain of custody; and,

(5) Quality assurance and quality control.

b. The groundwater monitoring program shall include sampling and analytical methods that are appropriate for groundwater sampling and that accurately measure hazardous constituents and other monitoring parameters in groundwater samples. Detection limits for those parameters that have a Maximum Contaminant Level (MCL) that has been promulgated under South Carolina R.61-58, State Primary Drinking Water Regulations, shall be, at a minimum, below the established MCL. Detection levels shall be as low as practically possible, and at the practical quantitation level (PQL) for those constituents with no MCL. Groundwater samples shall not be field-filtered prior to laboratory analysis.

c. The sampling procedures and frequency shall be protective of human health and the environment.

d. Groundwater elevations shall be measured and recorded for each well prior to initiating sampling procedures each time groundwater is sampled. The permittee shall determine the rate and direction of groundwater flow each time groundwater is sampled. Groundwater elevations in wells that monitor the same waste management area shall be measured on the same day to avoid temporal variations in groundwater flow which could preclude an accurate determination of groundwater flow rate and direction.

e. The permittee shall establish background groundwater quality in a hydraulically upgradient or background well(s) for each of the metals or constituents required in the particular groundwater monitoring program that applies to the Class Three landfill, as determined in Section258.54.a., or Section258.55.a. Background groundwater quality may be established at wells that are not located hydraulically upgradient from the Class Three landfill if it meets the requirements of Section258.51.a. (1). In order to establish background groundwater quality in a reasonable period of time, pursuant to Sections258.53.i. (1) and 258.53.i. (2), the permittee shall collect and analyze a minimum of four (4) independent groundwater samples from each compliance well and each background well prior to the end of the first year of operation. The Department may, on a case-by-case basis, approve an alternate subset of wells to be sampled for the establishment of background groundwater quality. The alternate subset of wells shall consist of a minimum of four (4) wells, or the total number of wells monitoring the landfill, whichever is least, and shall include all background well(s). This sampling and analysis shall be accomplished in a manner consistent with the requirements of Section 258.53.f. Pursuant to Section258.51.a. (1), the above samples shall represent the quality of background groundwater that has not been affected by leakage from a landfill.

f. The number of samples collected to establish groundwater quality data shall be consistent with the appropriate statistical procedures determined pursuant to paragraph g. below. The sampling procedures shall be those specified in Section258.54.b. for detection monitoring, Sections258.55.b. and d. for assessment monitoring, and Section258.56.b. for corrective action.

g. The permittee shall specify in the operating record a statistical method to be used in evaluating groundwater monitoring data for each metal or other hazardous constituent requiring statistical analysis. The statistical test chosen shall be conducted for each parameter in each well, every time samples are collected. The following methods may be used:

(1) 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;

(2) 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;

(3) 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;

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

(5) Another statistical test method that meets the performance standards of Section258.53.h. The permittee shall place a justification for this alternative in the operating record and obtain approval from the Department prior to the use of this alternative test. The justification shall demonstrate that the alternative method meets the performance standards of Section258.53.h.

h. Any statistical method chosen according to paragraph g. above shall comply with the following performance standards, as appropriate:

(1) The statistical method used to evaluate groundwater monitoring data shall be appropriate for the distribution of chemical parameters or hazardous constituents. If the distribution of the chemical parameters or hazardous constituents are shown by the permittee to be inappropriate for a normal theory test, then the data shall be transformed or a distribution-free theory test used. If the distributions for the 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 ground-water 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 shall 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 shall be protective of human health and the environment. 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;

(4) If a tolerance interval or a predictional interval is used to evaluate groundwater monitoring data, the levels of confidence, and for tolerance intervals, the percentage of the population that the interval contains, shall be protective of human health and the environment. 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;

(5) 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. Any practical quantitation limit (pql) 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 that are available to the facility; and,

(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.

i. The permittee shall determine whether or not there is a statistically significant increase over background values for each parameter or constituent required in the particular groundwater monitoring program that applies to the Class Three landfill, as determined in Section258.54.a. or Section258.55.a.

(1) In determining whether a statistically significant increase has occurred, the permittee shall compare the groundwater quality of each parameter or constituent at each monitoring well designated pursuant to Section258.51.a. (2) to the background value of that constituent, according to the statistical procedures and performance standards specified in paragraphs g. and h. above.

(2) Within a reasonable period of time after completing sampling and analysis, the permittee shall determine whether there has been a statistically significant increase over background for each metal or other hazardous constituent requiring statistical analysis at each monitoring well.

S.C. Code Regs. § 61-107.19.V.E.258.53