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After completing the well development, one water sample (#83250) was collected and contained in appropriate bottles prepared and supplied by the analytical laboratory The water sample was then shipped (by courier) in an iced cooler to Superior Analytical Laboratory in San Francisco for analysis. Well development and sample logs are attached. Well development and sampling details are described in Attachment A, Sections A-3 and A-4. LABORATORY RESULTS The water sample was submitted under chain-of-custody to Superior Analytical Laboratory for the following analyses- Total Petroleum Hydrocarbons (TPH) extractable by EPA Method 8015M/3550 (diesel range) TPH purgeable by EPA Method 8015M/5030 (gasoline range) Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) by EPA Method 602 Superior is certified by the California Department of Toxic Substances Control (DTSC) for the requested analysis The laboratory data sheets and chain-of-custody forms are attached. The laboratory reported low concentrations of TPH as diesel at 64 ug/1 and benzene at 0 4 ug/l. No concentrations of TPH as gasoline or toluene, ethylbenzene, and x lenes were detected above the laboratory analytical reporting limits y CONCLUSIONS The reported concentration of TPH as diesel is below the EPA's suggested no adverse response level (SNARL) of 100 ug/l Similarly, benzene was reported below the State drinking water maximum concentration limit (MCL) of 1 0 ug/l and the State action level of 0.7 ug/1. Since the source of contamination (the tank) and affected soil have been removed, Kleinfelder recommends completing the second sampling round to verify the results No additional groundwater assessment appears to be warranted at this time. The next sampling event is scheduled for May 10, 1993 LIlVIITATIONS Kleinfelder performed this investigation in accordance with generally accepted standards of care which exist in Northern California at this time Conclusions in this report are based on the analytical results of one water sample collected from MW-1 It should be recognized that definition and evaluation of environmental and geologic conditions is a difficult and inexact art Judgments leading to conclusions and recommendations are generally made with incomplete knowledge of the subsurface conditions present More extensive studies, including subsurface investigations, may be performed to reduce uncertainties H Cal West Concrete Cutting, Inc wishes to continue with this investigation, Kleinfelder should be notified for additional consultation No warranty, expressed or implied is made FR10-26(1993) Page 3 of 4 Copyright 1993 Klemfelder, Inc 24-220172-A00 KLEINFELDER 3077 Fite Circle, Sacramento, CA 95827 (916) 366-1701