ARCHIVED REPORTS_PHASE II ENVIRONMENTAL SITE ASSESSMENT

Home Browse Search

WGIR, • soultlhwest, l[rtc. Utility lines appear to be restricted to the far western and southwestern areas of the site, and this investigation did not identify any underground utilities that would be likely to provide preferential pathways for migration of contaminants. 11.4 Potential Receptors The Phase I ESA determined there were no water supply wells located within 0.25 mile of the site. The South Ditch, the storm water drainage located adjacent to the south property line, flows west into a storm water retention pond. The San Joaquin River lies just beyond the pond, approximately 1,200 feet west of the site. A small wetland area was identified approximately 0.3 mile southwest of the site, and larger wetlands are located about 0.2 mile to the west. However, no sensitive habitats have been identified within 500 feet of the site. 11.5 South Ditch Exploration of the banks of the South Ditch in the eastern portion of the site determined the layer of automotive debris to typically be about six inches thick along the north bank, with a maximum thickness of approximately one foot. It was determined to extend laterally for a maximum of 610 feet along the north bank. Offsite along the south bank the debris is also • typically about six inches thick and extends laterally for approximately 980 feet, with an approximately two-foot-thick zone extending along the south bank for at least 100 feet. Two excavations made south of the unpaved access road along the fence found the debris in that area to be less than six inches thick. Visual observation of the debris on the ditch banks indicates it is composed primarily of metal, rubber, foam, wire and plastic automobile fragments, typically less than about one foot in size. This is consistent with what is often referred to as "auto shredder residue" (ASR) or"fluff' and would have been produced by operation of the shredder recently dismantled and removed from the Learner site. Typical contaminants found in ASR include petroleum hydrocarbons, lead, cadmium, chromium, mercury, arsenic and PCBs. The shallow soil sample taken from B-16 near the South Ditch contained detectable PCBs, TPH-d, TPH-mo and O&G as well as concentrations of lead, cadmium and chromium exceeding reference levels. These analytical findings are consistent with impact from the debris produced by automobile shredding operations. Analysis of the soil samples taken from the south bank of the ditch adjacent to the Learner site exhibited detectable concentrations of TPH-d and TPH-mo as well as zinc, copper and nickel concentrations exceeding the reference levels, suggesting this area has also been impacted by Learner's operations. • 704. PRIM 29 July 21, 2008