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Cahfornia Department of Transportation Revised September 23, 1994 Project No. 102818-01 Groundwater samples were collected from rune of the groundwater morutoring wells. ' Groundwater monitoring wells MW-10, MW-11, MW-12, MW-13, MW-14, MW-16, MW-19, MW-20, and MW-24 were sampled between May 25 and May 27, 1994 Groundwater imonitoring wells were purged using a 2-inch diameter submersible pump The submersible pump and associated hoses were decontaminated after each use with a solution of potable iwater and tnsodium phosphate, followed by a potable water rinse and a deioruzed water rinse The interior and exterior of the pump and hoses were washed by submersing the equipment in the solutions and drawing wash and rinse water through the pump system. A minimum of three casing volumes were purged from each of the monitoring wells prior to collection of a water sample. Temperature, pH, and specific conductance measurements were made in the field for the purpose of establishing when a representative groundwater rsample could be taken Purging continued in each well until pH, temperature, and conductivity did not vary by more than 10 percent The monitoring well purge water was placed in labelled 55-gallon, DOT-approved drums and left on site in the stewardship of Caltrans Field measurements and general observations for each well were recorded on the well sampling records presented in Appendix A After purging, the water in each well was allowed to recover to at least 80 percent of its original elevation Water samples were then collected using a disposable, Teflon, bottom- discharging barter, transferred to an appropriate sample container, labelled, and placed in a cooler containing ice at 4 degrees Celsius under chain-of-custody protocol Water samples were collected during May 25 through May 27, 1994 Samples were secured in a cooler containing ice at 4 degrees Celsius and transferred by plane to San Diego on May 28, 1994, and then placed in refrigeration at the San Diego office of Ninyo & Moore Samples were then delivered to Quality Assurance Laboratory on May 31, 1994, for chemical analysis Soil stockpile samples were collected on June 3, 1994, and also secured in a cooler at 4 degrees Celsius containing ice and transferred by truck to San Diego on June 3, 1994, and then placed in refrigeration at the San Diego office of Ninyo & Moore Samples were then delivered to Quality Assurance Laboratory on June 6, 1994, for chemical analysis Ninyo & Moore attempted to locate a qualified analytical laboratory in the Stockton area, however, due to associated increased costs in analysis and Caltrans contract limitations on Minority 4 �dGtlL�l�l&�®®QCT