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Recommendation for No Further Action - 2 - 30 July 2009 <br /> Kishida Property, San Joaq�County <br /> located in areas where stained and discolored soils were observed on the ground, or where <br /> waste storage containers had been staged. Fourteen soil samples and two groundwater <br /> samples were collected and analyzed for volatile organic compounds and total petroleum <br /> hydrocarbons. Surface soil samples were also analyzed for arsenic, barium, cadmium, <br /> chromium, lead, mercury, selenium, and silver. <br /> Extent defkied: No constituents of concern were reported above the laboratory reporting <br /> limits in any of the soil or grab groundwater samples. Lead, chromium VI, and mercury by the <br /> DI-WET method were not present in surface soils above laboratory detection levels, and <br /> therefore do not pose a potential to leach to groundwater. Arsenic, barium, cadmium, total <br /> chromium, lead, mercury, selenium, and silver were further analyzed in the surface soil <br /> samples at the Central Valley Water Board staff's request in January 2009, to ensure that soil <br /> concentrations are protective of human health. Central Valley Water Board staff requested <br /> that these metals results be compared to EPA Region 9 Preliminary Remediation Goals <br /> (PRGs). Only arsenic, barium, and chromium were detected in the surface soil samples. <br /> Arsenic ranged in concentration from 2.9 to 4.4 milligrams per kilogram (mg/Kg); the PRG is <br /> 1.6 mg/Kg. Barium was present in all.samples but well below the residential PRG of 15,000 <br /> mg/kg. The maximum concentration of chromium in soil, 49 mg/Kg, was well below the <br /> residential PRG of 2800 mg/Kg. <br /> Estimated Residual Mass: There is no significant pollutant mass in soil above the saturated <br /> zone that has the potential to leach to groundwater. <br /> Trend analysis: Only one.sampling event.occdrred. All sample results were below levels of <br /> concern for protection of human health and water quality. <br /> Threat to groundwater: There is no evidence of an ongoing release and no indication that <br /> site-related pollutants have the potential to leach to groundwater. <br /> Threat to Human Health: Arsenic in surface soil is present at concentrations in excess of the <br /> EPA Region 9 PRG for industrial soils (1.6 mg/kg). The concentrations of arsenic.are believed <br /> to be consistent with regional background concentrations. No other constituents exceed <br /> PRGs. <br /> Sensitive Receptors: There are no chemicals of concern to sensitive receptors in the <br /> immediate area. <br /> Summary: Central Valley Water Board staff concur with the determination that the residual <br /> concentrations of metals at the site do not present a threat to water quality or human health. <br /> All sample results were either below levels of concern for protection of human health and <br /> water quality or, in the case of arsenic, within the range of background concentrations. <br /> Petroleum hydrocarbons and volatile organic compounds were not present above detection <br /> limits in soils or groundwater in areas with,visible staining or known releases. Based on this <br /> evaluation, a No Further Action determination is recommended at this time. <br /> Attachment(s) 1. Site Map <br />