SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

San Joaquin County DIRECTOR Donna Heran,REHS /o. Environmental Health Department c p ASSISTANT DIRECTOR 600 East Main Street Laurie Cotulla,REHS Q y � Stockton, California 95202-3029 � PROGRAM COORDINATORS Mike Huggins, REHS,RDI Margaret Lagorio,REHS Website: www.sjgov org/ehd Robert McClellon,REHS F o Phone: (209)468-3420 Jeff Carruesco,REHS, RDI Fax: (209)464-0138 Kasey Foley,REHS April 9, 2009 Craig Ogata Director of Facilities Management 212 N. San Joaquin Street Suite A Stockton, CA 95202 Subject: San Joaquin County Corp Yard 1810 E. Hazelton Avenue Stockton, CA The San Joaquin County Environmental Health Department (EHD) has reviewed our file for the above subject site and provides the following comments. The EHD is aware that there is a limited amount of money allocated by the County for investigation and remediation of their sites that have been contaminated by unauthorized releases from underground storage tanks (UST). Two of those contaminated UST sites have received closure letters from the EHD this year. The active responsible party for one of the sites is now the City of Stockton. The EHD has allowed the delay of further investigation and remediation at 1810 E. Hazelton while the investigations were completed at other sites. The further investigation and remediation of 1810 E. Hazelton should now be initiated. There is documented soil contamination to a depth of 60 feet below grade in the areas of monitoring wells MW1 and MW2, so the vertical extent of soil contamination is not defined in these areas and must be investigated. The vertical extent of the groundwater contamination has not been investigated either, so this investigation must be performed as well. The lateral extent of the shallow groundwater contamination is defined except down-gradient of monitoring wells MW2 and MW4 so the extent of the shallow groundwater contamination also must be defined. Remediation wells SVE-1A, 1B, 1C and AS-1/SVE2B were installed in March 2005, but a pilot test to see if air sparging (AS) and vapor extraction (VE) is a feasible remedial alternative has not been conducted. A pilot test for AS and VE must be conducted and if it is a feasible, cost- effective alternative, then it can be evaluated to see if it is the most cost-effective alternative. Remediation of the contamination should begin before the end of this year. The results of the groundwater samples from monitoring wells MW3 ,MW5, and MW7 have been non-detect for contaminants for two years. Sampling of the water from these wells can be reduced to biennial. Sampling of the water from MW6 can be reduced to annual. Quarterly sampling of MW1, MW2 and MW4 should continue. Analysis of the water samples can be reduced to TPH as gasoline, benzene, toluene, ethyl-benzene, xylene and methyl tert butyl ether on all the wells.