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a in low Mr in KLEINFELDER File No. 20-3978-01.W 10 July 26, 1997 case, Kleinfelder would recommend no further investigation or mitigative measures as it relates to the presence of limonene. 3. The water samples obtained were analyzed for CAM 17 Metals per Title 22 of the California Code of Regulations (22CCR). The only metals detected were arsenic (ND to 0.34 mg/L), barium (0.14 to 1.4 mg/L), mercury (ND to 0.00047 mg/L), vanadium (ND to 0.045 mg/L) and zinc (ND to 0.26 mg/L). The maximum contaminant levels (MCLs) listed in 22CCR§64431 for these compounds are arsenic (0.05 mg/L), barium (1.0 mg/L), mercury (0.002 mg/L), vanadium (no MCL listed) and zinc (no MCL listed). There is a Secondary Maximum Contaminant Level (SMCL) for zinc of 5.0 mg/L listed in 22CCR§64449.1. However, there is no SMCL listed for vanadium. The concentrations of mercury present in the samples obtained do not exceed the MCL and do not appear to be of concern. The concentrations of zinc present in the groundwater do not exceed the SMCL and do not appear to be of any concern. The concentrations of vanadium present are very low; and there is no MCL or SMCL listed in 22CCR. Therefore,the concentrations present are not alarming. Arsenic was not detected in the "Cattle Pen Well", the "Domestic Well", Production Well 8, Monitoring Well 3 (downgradient of a portion of the wastewater ponds), and Monitoring Well 5 (off-site upgradient well). Arsenic was detected above the MCL in Monitoring Well 1 and 2 (downgradient from the lime ponds), Monitoring Well 4 (downgradient from the mud ponds), and Production Wells 5 and 7 (downgradient to side-gradient from the lime ponds). Arsenic is a naturally occurring element and can exist in groundwater in very high concentrations such as that in the west side of the San Joaquin Valley. According to the 1994 Annual Water Report by the City of Manteca, the city's water supply ranged in arsenic concentration from 0.008 - 0.026 mg/L. Although the source of the arsenic in the groundwater samples is unknown, one explanation may be the importing of sugar beets from the west side of the San Joaquin Valley. Excess soil from that region which is naturally high in arsenic may have been adhered to the beets and found their way to the mud and lime ponds. In either case the capping of the site as is common in redevelopment projects of this type, the elimination of the source (beet importation) and the potential removal or capping of the sediments within the lime and mud ponds may act to mitigate these concentrations. 20-3978-01.W10/2017L155 Page 17 of 50 Copyright 1997,Kleinfelder,Inc.