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H�tl, 3v <br /> �� A S S 0 C I A T E S I N C <br /> SAMPLING ACTIVITIES <br /> Groundwater samples were collected from wells MW-1, MW-2, and MW-3 atter purging and <br /> stabilization of physical parameters (pH, electrical conductivity, and temperature). Well purge <br /> logs and field notes are contained in Attachment 1. Collected groundwater samples were placed <br /> on ice and transported under chain-of-custody protocol to State-certified Excelchem <br /> Environmental Labs (ELAP #2119). Samples were analyzed for priority metals. <br /> ■ Analysis of the samples from wells MW-2, and MW-3 detected zinc at concentrations of 60 <br /> and 10 parts per billion (ppb), respectively. The detectable concentrations of zinc in all three <br /> wells were well below the Secondary Drinking Water Standard for zinc of 5,000 ppb. <br /> • The samples from well MW-2 contained chromium at a concentration of 10 ppb. The <br /> detectable concentration of chromium in well MW-2 was below the maximum contaminant <br /> level (MCL) for chromium of 50 ppb. <br /> ■ Analysis of the samples from wells MW-1, MW-2, and MW-3 detected arsenic in all three <br /> wells at concentrations of 9.4, 10, and 67 ppb, respectively. The detectable concentrations of <br /> arsenic in well MW-3 exceeded the MCL for arsenic of 50 ppb. <br /> • Analysis of the samples from wells MWA and MW-2 detected selenium at concentrations of <br /> 9.0 and 58 ppb, respectively. The detectable concentrations of selenium in well MW-2 <br /> exceeded the MCL for selenium of 50 ppb. <br /> ■ The sample from well MW-2 also contained copper and nickel at concentrations of 20 ppb <br /> each. Copper was below the Secondary Drinking Water Standard of 1,000 ppb and nickel <br /> was below the MCL of 100 ppb. <br /> Concentrations of chromium, copper, and nickel have increased in well MW-2 since the last <br /> monitoring event. Well MW-2 is located on the northern portion of the property, upgradient of <br /> site operations. The concentrations of metals detected in well MW-2 are significantly higher <br /> than in wells MW-1 and MW-3 and do not appear to be related to site operations. <br /> Analytical results are summarized in Table 2 and laboratory reports and chain-of-custody <br /> documentation are contained in Attachment 2. <br /> During this monitoring event, the wells were found to be in good condition with no visible <br /> defects. The next scheduled activities are in March 2003 and include depth to groundwater <br /> monitoring and reporting. <br /> • <br /> w:\62580\reports\3rdgtr02.doc 2 <br />