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r Ar GEOMATRIX vicinity of the ponds. Concentrations of these constituents appear relatively constant over time for most of the monitoring wells except for monitoring well LP-4, which has a high variability in concentrations. The consistency in general mineral concentrations in most wells make it likely that these data are the result of a historical release of inorganic constituents from the ponds. The data indicate the historical release was in the vicinity or upgradient of well LP-4; however,the exact location of the release is unclear from the currently available data. Parametric statistical analyses were performed for the inorganic monitoring parameters where sufficient data were available and the data were normally distributed. Statistical calculations were performed for these constituents using a 95 percent confidence interval calculated for the mean of the background data set(well LP-7). The upper bound of the confidence interval was used as the concentration limit. Since the data for potassium did not appear to be normally distributed,parametric analysis was not performed on these data. Four additional inorganic parameters(chemical oxygen demand,bicarbonate,total alkalinity, and carbonate) and 21 dissolved metals are monitored annually. The results of only four sampling events are available for these constituents. Since there is so little data available for these constituents, a new release of these constituents cannot be readily discerned. 5.0 CORRECTIVE ACTION WORK PLAN The RWQCB has declared a release to groundwater of dissolved solids from the area of the ponds and has requested development of a CAP (RWQCB, 2005). Article 1 of Title 27, CCR, requires operators of regulated facilities to implement water quality monitoring and response programs. The default program is the detection monitoring program (DMP) described in Section 20420. When detection monitoring indicates a"measurably significant evidence of a release" (Section 20385) from a regulated unit,the operator is required to implement an evaluation monitoring program(EMP) (Section 20425)to"assess the nature and extent of the release." A CAP (Section 20430)is required"to remediate releases from the unit, to...achieve the water standard (concentration limits) for that unit." Simplot implemented detection monitoring in 2001 and has not reported measurably significant evidence of a current release from the lined ponds. Although,the detection monitoring data and shallow groundwater monitoring data indicate a historic release of dissolved solids from the area of the ponds(Simplot, 2005); the date and source of the release(s) is not known. Geomatrix evaluated groundwater monitoring data and proposed concentration limits for dissolved solids in the WQPS for detection monitoring below Simplot's lined ponds 1:\6000s\6 74 1.000\A rch i ve\6741-13.doe 5