ARCHIVED REPORTS_XR0008225 - Laserfiche WebLink

Home Browse Search

CLOSURE REQUEST REPORT Section No 3 0 Former American Forest Products Company 07/31/01 2801 West Lane Page 3-5 Stockton California The excavated material (approximately 2,050 cubic yards of soil) was removed and transferred to an on- site biotreatment cell Upon excavation and tilling, the final volume of soil increased to approximately 2,550 cubic yards The soil was treated according to the remediation work plan until concentrations declined enough to meet the requirements for off-site disposal in a Class Il landfill An estimated residual mass of 12,500-kg TPHd was calculated to be present in the subsurface following the completion of excavation activities in 1991 It is assumed that the residual TPHd mass is still present in the subsurface, although natural biodegradation is likely to have reduced the total mass 35 GROUNDWATER ANALYTICAL DATA Groundwater samples from the site have been collected and analyzed since August 1990 Analytical parameters have included TPHd, TPHg, BTEX, volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), and fuel additives The most recent sampling event was conducted during March 2001 Groundwater analytical results for TPHd and unknown hydrocarbon are included in Table 4, and November 2000 and March 2001 results are shown in Figures 15 and Figure 16, respectively Unknown hydrocarbon refers to hydrocarbon patterns observed by the laboratory, which do not match the diesel standard The unknown hydrocarbon has been attributed to detections of weathered diesel, and to naturally-occurring organic compounds Groundwater analytical results for fuel additives, including methyl tertiary-butyl ether (MTBE) and 1,2- DCA, are included in Table 5 Maximum reported concentrations for groundwater constituents together with the California Maximum Contaminant Level (MCL) are presented in the table below Maximum MCL Constituent Detection Location Date (&&) TPHd 440 DMW-6 11/15/00 1001 Unknown Hydrocarbon 780 DMW-6 919199 none Benzene not detected — — 1 0 Toluene 0 63 EEL DMW-4 512/95 150 Eth ]benzene not detected -- — 700 Xylenes not detected — — 1,750 TPH9 not detected — — none Ethanol 6 9 ml DMW-1 8/25100 none 1,2-Dichloroethane 40 pEj DMW-6 and DMW-5 11/15/00 and 5126/95 0 5 Carbon Tetrachloride 0 65 DMW-5 5/26/95 0 5 Chloroform 3 8 p DMW-5 5126/95 100 Semivolatile Or anic Compounds Not Detected — — — i Taste and Odor Threshold mg/L = nulligrams per titer TPHd = total petroleum hydrocarbon as diesel TPHg = total petroleum hydrocarbon as gasoline P91L = micrograms per liter K 1840191afprafp_closure_rptdoc