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FIELD REPORT WELL INSTALLATION SAN JOAQUIN COUNTY MOSQUITO ABATEMENT DISTRICT LODI FACILITY, LODI, CALIFORNIA On July 14, 1992, ROY F WESTON, INC. (WESTON) conducted a site investigation at the San Joaquin County Mosquito Abatement District (SJCMAD) facility in Lodi, California (Figure A-1) This investigation was performed to gain further information on the extent of petroleum hydrocarbon compounds in soil and groundwater at the site All work was performed in accordance with the WESTON Work Plan dated April 1, 1992. Drilling and Sampling ' The monitoring well boring was drilled using 8-inch hollow-stem augers and a truck-mounted drill ng Soil samples for lithologic description were collected using a 5-foot-long continuous- core barrel sampler The sampler was placed inside the first 5 feet of auger and extended I approximately 6 inches below the end of the auger during drilling operations which allowed for the collection of relatively undisturbed soil samples Soil samples were collected for potential laboratory analyses at 10 foot intervals using a California-modified split-spoon sampler lined with three 2-inch-diameter by 6-inch-long brass liners These samples were field tested for organic compounds using an HNu photoionization detector (PID) Subsurface samples were collected by drilling to the appropriate depth and then driving the sampler ahead of the auger using a 140-pound drive hammer The number of blows required to advance the sample 6 inches was recorded on the boring logs The well log for BAW-4 is included at the end of this field report One brass liner from each sample interval was preserved for Potential shipment to the laboratory. The brass liner selected for shipment was preserved by sealing both ends with Teflon sheeting and tight-fitting plastic caps. Each liner was labeled with a unique sample number, boring number, depth of sample, site name, date, time of collection, and any other pertinent information. After sample preparation, the brass liner was placed in a ziplock plastic bag in a cooled ice chest pending delivery to the laboratory No soil samples were submitted to the laboratory for chemical analyses because there were no above-background volatile organic compound (VOC) levels detected with the PID field screening instrument Field screening for VOCs was performed on soil from one of the brass liners from each 10-foot sample interval. The headspace-screening technique involved placing a portion of each sample into a clean resealable plastic bag and promptly sealing the bag After a minimum of five minutes, to allow for volatilization of any constituents that may have been present, a PID probe was inserted into the bag and a measurement was recorded. Results of the screening are presented on the boring log The PID was calibrated daily using isobutylene as the calibration gas. ' MXC\R"S\S1CMAa WP A - 1 10/14192