SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

PUBLIC H15ALTH SERVICES FILE COPY SAN JOAQUIN COUNTY r � Z ENVIRONMENTAL HEALTH DIVISION Karen Furst, M.D., M.P.H., Health Officer 304 East Weber Avenue, Third Floor • Stockton, CA 95202 209/468-3420 OCT 2 6 2000 PAUL SUPPLE GARY SCANNAVINO ARCO PRODUCTS COMPANY SCANNAVINO PROPERTIES P 0 BOX 6549 5463 E CHEROKEE LANE MORAGA CA 94570 STOCKTON CA 95215 RE: ARCO Station #595 SITE CODE: 0707 6100 N. Hwy. 99 Stockton CA 95209 San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) has reviewed the"Site Assessment Report" dated October 2, 2000 that was submitted by SECOR International Incorporated (SECOR)on behalf of the above referenced site and has the following comments. The report details site work that took place during the first week of June 2000, when four groundwater monitoring wells and three soil borings were installed onsite. Soil samples for analysis were collected at five-foot intervals from each boring. Selected samples were submitted for analysis. Minor detections of petroleum hydrocarbon contamination were made in soil samples at depths ranging from 40 feet below surface grade (bsg)to 60 feet bsg. Thirteen of the soil samples were analyzed for fuel oxygenate additives, 1,2-dichloroethane and ethylene dibromide by EPA Method 8260. Of these thirteen samples, only one had a detection of contamination above the reporting limit. Sample MW-4 at 60-feet bsg had 0.308 milligrams per kilogram (mg/kg)of methyl tertiary butyl ether(MtBE). However, the reporting limits used in these soil analyses were elevated above the standard accepted detection limit for ether oxygenates of 0.005 mg/kg. The documented site work was to be performed in accordance with the"Work Plan for Site Assessment'dated February 28, 2000 that was submitted to PHS/EHD by SECOR. PHS/EHD approved the work plan in correspondence dated March 14, 2000 with the condition that the installed monitoring wells should have a maximum screen length of 20 feet. The work plan had suggested installing screen lengths of up to 70 feet. After discussions with SECOR, PHS/EHD agreed that should soil contamination be apparent while drilling the two monitoring wells located near the current dispenser islands (MW-2 and MW-4), screen intervals of greater than 20 feet in length may be approved. The intent of the longer screen intervals was to have the possibility of using these wells at a future date for soil vapor extraction. This verbal agreement between PHS/EHD and SECOR was documented in PHS/EHD correspondence dated March 22, 2000. On the first day of field work, June 1, 2000, PHS/EHD personnel discussed this agreement with the SECOR staff geologist working on site. When PHS/EHD returned to the site for a grout inspection of MW-1,which is located on the east side of the property near the operating tank farm, they were informed that the well had been built with 35 feet of screen interval. A Division of San Joaquin County Health Care Services