WORK PLANS - Laserfiche WebLink

Home Browse Search

s Beacon #3641 page 2 1210 E. Hammer Lane, Stockton In evaluating the SCM, EHD concluded that the investigative phase for this site is not complete. EHD noted that MW-12 and MW-13 ground water contamination data indicates that the ground water contamination detected in soil boring B-5 is not present after two sampling events at 130 feet below ground surface ('bgs). Although the placement of these wells was outside the 'core' area as defined by laboratory data included in the SCM, the ground water data collected so far from MW-12 and MW-13 indicates that the contamination noted in B-5 at 130' bgs has not migrated laterally. EHD concurs with your consultant's conclusion that the ground water plume is vertically delineated. Although the petroleum plume may be vertically delineated in the core area to the maximum depth investigated, there is a data gap in the interval from 75' bgs (MW-5) to the next deeper wells (MW-12 & 13) at 130'-135' bgs. The contamination detected at 100' bgs in B-5 has not been adequately investigated. In order to investigate the elevated ground water contamination in MW-5 and confirm if there is elevated ground water contamination at -100 'bgs as documented from B-5, EHD will require a well to be placed near the B-5 location in the sand zone at approximately 95'-100' bgs. This well is to be sampled quarterly for all constituents for at least one year. If it can be shown that a change in the sampling and analytical suite can be justified, EHD will evaluate a request at the end of the year's period. A work plan for the monitoring well installation should be submitted to EHD immediately. Please continue to address your reports and correspondence to Michael Infuma and you may contact him at (209) 468-3454 should you wish to call. Donna Heran, RENS, Director Enviro mental Health Department 91�e/ � Michael J. Infuma Jr., Senior REHS Margare Lagorio, R S LOP I Site Mitigation Unit IV Supervisor c: CVRWQC13 —James Barton, Sacramento. c: SWRCB-CUF— Mark Owens, Sacramento. c: Horizon — R. Smith, 4970 Windplay Dr. #C5, EI Dorado Hills, 95762