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California ReLional Water Quality Control Board <br /> Central Valley Region <br /> Robert Schneider,Chair <br /> Winston H.Hickox Gray Davis <br /> Secretaryfor \2' Sacramento Main Office Governor <br /> Environmental \�% Internet Address: http://www.swrcb.ca.gov/rwgcb5 <br /> Protection v 3443 Routier Road,Suite A,Sacramento,California 95827-3003 <br /> moo` Phone(916)255-3000-FAX(916)255-3015 <br /> 30 July 20� All <br /> Mr. Ed Stetson <br /> Silgan Containers C1�a�tion <br /> 1815 Navy Drive <br /> Stockton,CA 95206 <br /> REVIEW SITE INVESTIGATION REPORT,SILGAN CONTAINERS, 1815 NAVY DRIVE,STOCKTON, <br /> SAN JOAQUIN COUNTY <br /> Regional Board staff reviewed the 5 June 2002 Additional Site Investigation and Groundwater Monitoring Well <br /> Abandonment Report(Investigation Report) submitted by Enfra LLC(Enfra)on behalf of Silgan Containers <br /> Corporation(Silgan). The Investigation Report documents the destruction of monitoring well GW-2, installation <br /> of two additional monitoring wells, and presents monitoring and sampling results for groundwater samples <br /> collected on 21 March 2002. <br /> Monitoring well GW-1 was destroyed under San Joaquin County Environmental Health Department permit and <br /> inspection by overdrilling and backfilling the boring with neat cement grout. Monitoring wells MW-2 and MW-3 <br /> were installed inside the Silgan Containers building approximately 30 feet east, and 30 feet northeast of the <br /> former underground storage tank(UST), respectively. Both wells are screened from 7 to 27 feet, and the average <br /> depth to water is approximately 12 feet in the two new wells. <br /> Monitoring wells MW-1, MW-2, MW-3, and GW-2 were monitored and sampled on 21 March 2002. The <br /> groundwater flow direction calculated on 21 March 2002 was to the southwest in the vicinity of the former UST. <br /> Cis-1,2-dichloroethene,the only constituent identified during this sampling event,was identified in monitoring <br /> wells MW-1 at 4.6 micrograms per liter(µg/1)and MW-2 at 13 µg/1. (The Primary Maximum Contaminant Level <br /> for cis-1,2-dichloroethene is 6 µg/1.) <br /> With the installation and sampling of the new monitoring wells, Silgan concludes that the groundwater has not <br /> been adversely impacted by the former UST release, and requests site closure. <br /> Board staff have the following comments on the Investigation Report: <br /> 1. Due to the cis-1,2-dichloroethene contamination identified in groundwater and the changes in the <br /> groundwater flow direction at this site,we will not consider the site for no further action at this time. <br /> 2. With the installation of the two additional monitoring wells,the extent of groundwater contamination <br /> remains undefined east of monitoring well MW-2, and southwest of the site in the current <br /> groundwater flow direction. Future quarterly monitoring events are necessary to determine the <br /> dominant groundwater flow direction and determine if groundwater fluctuations will cause <br /> contaminants to migrate in a southwesterly direction. A minimum of four consecutive quarters of <br /> California Environmental Protection Agency <br /> Ca Recycled Paper <br /> The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. <br /> For a list of simple ways you can reduce demand and cut your energy costs,see our Web-site at http://www.swrcb.ca.gov/rwgcb5 <br />