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GEOMATRIX beneath the ponds in the uppermost aquifer was to the west based on groundwater elevation data collected in September 2002 (Figure 2). This direction of groundwater flow is typical of previous groundwater measurements collected from June 2001 to August 2002, which indicate flow directions usually vary between northeast and northwest. Occidental has been monitoring groundwater in three zones for the past 23 years. The three zones identified by Occidental are called shallow groundwater(31 to 83 feet bgs), intermediate groundwater(84 to 150 feet bgs), and deep groundwater(151 to 218 feet bgs). 4.0 WATER QUALITY PROTECTION STANDARDS According to Title 27, Section 20390, California Code of Regulations(CCR),the WQPS for groundwater comprise the following elements: COCs, concentration limits, and the point of compliance and monitoring points. The concentration limits for anthropogenic constituents are the method detection limits(MDLs) for each analyte. The background concentrations of the CDCs were evaluated to provide the basis for determining an appropriate method for establishing concentration limits. Concentrations limits on Table 2 have been updated with groundwater monitoring data through 2004. The updated concentrations limits were calculated using the same methods as described in the WQPS report(Geomatrix, 2003). Groundwater monitoring samples have been collected annually for analysis of volatile organic compounds(VOCs)using U.S. Environmental Protection Agency(EPA) Method 8260. VOCs have not been detected routinely in samples collected from the groundwater monitoring network. The inconsistent nature of these detections and the trace levels at which the constituents were detected, combined with the lack of detections in wells of the groundwater monitoring network,indicates that there is no ongoing release of VOCs from the ponds. Since these VOCs are not naturally occurring in groundwater, the MDL was proposed as the concentration limit for VOCs. Inorganic COC parameters are defined in the MRP. The monitoring frequency of these constituents varies from quarterly to annually depending on the constituent. General mineral parameters, including sulfate, total dissolved solids (TDS), sodium, calcium, nitrate(quantified as NOA chloride, and potassium are analyzed on a quarterly basis. Consequently, the results of 15 sampling events are available for these constituents. Compared to general mineral constituents in groundwater from background well LP-7, elevated concentrations of these seven general mineral parameters occur in downgradient and cross-gradient monitoring wells. These elevated concentrations appear to be the result of a release of inorganic constituents in the I:\6000s\6741 A00\Archive\6741-13.doc 4