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NITRATE AND DBCP TESTING We understand that no wells exist on the site. As part of a previous study for others, Kleinfelder had sampled water from several wells in the project area for chemical testing. The groundwater was obtained by Kleinfelder staff using clean procedures from wells located approximately 500 feet to the west at the Teichert Aggregate Plant and 2,000 feet to the northeast at the Rolab facility south of Linne Road, among other locations farther away from the project site. For the purposes of our prior work, only Teichert's sample was tested for DBCP and only Rolab's sample for Nitrate. The samples were taken on March 9 and 10, 2000. The water samples were submitted to Sequoia Analytical and Alpha Analytical using chain-of-custody procedures for DBCP and nitrate testing. The results of our tests and a copy of the chain-of-custody are attached. For your information, other samples collected as part of this study farther away than those listed above also contained no detectable DBCP concentration and had lower Nitrate results than Rolab. These test results can also be provided upon request. NITRATE LOADING CALCULATIONS Per San Joaquin County Public Health Services (SJCPHS) Department Environmental Health Division (PHS/EHD)requirements,the following summarizes our nitrate loading calculations for the proposed leach field. The drinking water standard for nitrate is 45 milligrams per liter(NO3) and 10 mg/l as Nitrogen (l) in groundwater. In our evaluation of nitrate loading, we have used the Hantzsche mass balance equation (source: Predicting Ground-Water Nitrate-Nitrogen Impacts, Hantzsche and Finnemore (1992)), which is presented below with an explanation for each factor and the value used in our study. The selection of parameters was based on previous studies and investigations performed by our firm and others, San Joaquin County Sewage Standards, and information provided in a report dated March 19, 1997 prepared by the Questa Engineering Corporation and authored by Mr. Hantzsche for a development in the Stockton area. Ne =AWNw 0-Dl +(1V r AW+r Where: N, = Average calculated nitrate-nitrogen in groundwater resulting from domestic sources and precipitation—mg/l, as N A = Number of dwelling units per acre on septic tanks (unit/acre) = 0.38 (estimated based on an estimated water usage of 15 gal./person/day for 20 employees at an industrial facility without a cafeteria, per the SIC PHS/EHD Sewage Standards, divided by 150 gal./day to obtain an equivalent number of homes, divided by 5.2 acres) W = Annual wastewater loading per dwelling unit per acre (inches) =2.0 inches (per year per dwelling unit assuming a flow of 150 gal./day/dwelling unit) 13384.G01/2002R270 March 19,2002 O 2002 Kleinfelder,Inc. Page 2 of 3 KLEINFELDER 2825 East Myrtle Street,Stockton,CA 95205-4794 (209)948-1345 (209)948-0621 fax