ARCHIVED REPORTS_XR0012607 - Laserfiche WebLink

Home Browse Search

0MUNI Quarterly Monitoring Report, First Quarter 1990 September 17, 1990 Former Unocal Station No. 2859 AGS 38012-2 The samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) using modified Environmental Protection Agency (EPA) Method 8015 and benzene, toluene, ethylbenzer,e, and total xylene isomers (BTEX) using EPA Method 602. Laboratory analyses were performed at the Applied GeoSystems !aboratory in Fremont, California (Hazardous Waste Testing Laboratory No. 1.53). The results of these and previous analyses are summarized in Table 3. Copies of the laboratory analysis reports and Chain of Custody Records are included with this report. Results of laboratory analyses indicate that concentrations of TPHg and BTEX are highest in samples from monitoring well MW-2, downgradient of a former dispenser island.. Concentrations of TPHg continue to increase in this well. Concentrations of BTEX in monitoring wells MW-1, MW-3, MW-4, and MW-5 ranged from 6.4 parts per billion(ppb) to below detection levels for the tests used; however, concentrations of TPHg range from 20 ppb to 300 ppb. Results of analyses indicated that concentrations of TPHg, benzene,and ethylbenzene increased in well MW-2 and that concentrations of TPHg increased in wells MW-4 and MW-S. We recommend continuing the quarterly monitoring of the groundwater in the wells while remedial alternatives are evaluated. We have scheduled the next sampling for the week of May 21, 1990. -' We recommd:nd a copy of this report be forwarded to Ms. Laurie Cotulla of the San Joaquin Local Health District,P.O.Box 2009,Stockton,California 95201,and Mr.Thomas D.Peltier of the California Regional Water Quality Control Board, Central Valley Region, 3443 Routier Road, Sacramento, California 95827-3098. Please call if you have questions regarding this report. Sincerely, Applied GeoSystems Eloise K. Frick Pr�o1jec/tJGeologist ; John B. Bobbitt R.G. 4313 Enclosure 3 AR,01160f 0,00SS/SM177S