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<br />Ground Water Protection <br />One upgradient and two downgradient ground water monitoring wells were installed to evaluate the <br />hydrogeology of the proposed cement kiln dust (CKD) disposal site. These wells appear to be <br />appropriately situated to detect any ground water impacts that may occur as a result of CKD disposal. <br />However, no samples have been collected for analysis of ambient ground water chemistry up to this point. <br />The hydrogeological and geochemical evaluation conducted indicates that the disposal of CKD in the <br />played out quarries will not adversely affect ground water quality. In order to assure that no adverse <br />impacts are occurring, the DMG will require that a ground water monitoring program be implemented at the <br />site in accordance with Rule 3.1.7 of the Construction Materials Rules. <br />The initial step in the implementation of Rule 3.1.7 is the characterization of ambient ground water quality. <br />This will involve the collection of 5 quarters of ground water chemistry data from the three monitoring wells <br />that have been installed. Data from the 2 downgradient wells can be considered to be ambient data up until <br />the time that initial CKD disposal occurs in the proposed disposal area. Once CKD disposal has <br />commenced, only information from the upgradient well can be presumed to represent ambient ground <br />water quality. The operator must provide a concise plan for the characterization of ambient ground water <br />quality. This plan must include a description of the method of sampling and the frequency of sampling and <br />reporting to the DMG. The plan must also include a list of parameters to be analyzed and specification of <br />water quality analysis methods and quality control and quality assurance measures to be employed. The <br />DMG suggests that for ambient ground water quality characterization afull suite of parameters be <br />evaluated over the five quarter characterization period. A full suite of parameters is listed in tables 1-4 of <br />'The Basic Standards for Ground Water' Regulation 41, (5 CCR 1002-41). It is particularly important that <br />pH and total dissolved solids (TDS) be included in the ambient quality characterization because these <br />parameters would be good indicators of CKD derived leachate present in ground water. Ifems from tables <br />1-4 that could be excluded from the characterization parameter list would be asbestos, chlorophenol, color, <br />corrosivity, foaming agents, and phenol. Once ambient ground water quality is established, a more limited <br />set of parameters may be monitored for the purpose of contamination detection monitoring. Since arsenic, <br />barium, chromium, lead, selenium, and thallium were all detected ai levels above the practical analytical <br />quantitation limit in the SPLP leachate, these metals must all be on the list of parameters included in the <br />detection monitoring plan along with pH and TDS. <br />The collection of ambient ground water quality data over a period of 5 quarters, as discussed in the <br />previous paragraph, is taken from the Hard Rock/Metal Mining Regulations at Rule 6.4.20(9)(b). However, <br />in order to conduct a valid statistical analysis of the data, it is the DMG's position that at least eight data <br />points will be required. In order to collect sufficient data for statistical analysis, it is suggested that the <br />operator collect two samples per quarter over the 5 quarter time period. The samples should be collected <br />at as close to equally spaced time intervals as possible. <br />Once the ambient ground water quality is established, numeric protection levels for ground water will be <br />specified and points of compliance determined. The frequency of sampling, method of reporting, and <br />length of post-closure monitoring period will also be established. The obvious choices for points of <br />compliance are the two downgradient wells that are in place. Since this ground water is unclassified, the <br />numeric protection levels will be set according to the Interim Narrative Standard for ground water adopted <br />by the Water Quality Control Commission which is that quality which meets the most stringent criteria set <br />