SU0003892 SSCRPT - Laserfiche WebLink

Home Browse Search

Project No.E8062.WTP Phase I Environmental Site Assessment/Lathrop,CA October 21, 1999 5. SUMMARY OF FINDINGS ., • The subject site consists of an approximately 100-acre parcel, which is predominantly farmland. Based on aerial photographic evidence and historical topographic maps, the property has only been used for agricultural purposes. Because of this exclusive use for agriculture, the only likely contamination on site may be pesttcr a residues withm e surficial soil. • Based on visual observations and conversations with the current property owner, there are no USTs on site. According to San Joaquin County Environmental Health Division (SJCEHD) and Lathrop Fire Department records, there appears to be no record of USTs or hazardous materials ever existing on the subject property. In addition, the SJCEHD had no records of the site ever being reported as contaminated. • Review of 17 State and Federal agencies and databases provided by Vista Information Solutions indicated that 4 known potential secondary contamination sites are located within a 1.25-mile radius of the subject site. Three of these sources are wells, which have never reported contamination. The fourth site is a former Class III solid waste landfill located immediately southwest of the site. In view of the above findings, it is the opinion of TERRASEARCH, inc., that further environmental assessment of the subject site is warranted, and should include the following prior to development of the land: _ • Based on the current and past use of the property for agricultural purposes, the surficial soil should be evaluated for the presence and/or absence of organochloride and metal pesticides and herbicides. 10 soil samples (one sample per 10 acres) should be collected from the surficial soil (approximately 6-inches below the surface), submitted under chain of custody documentation to a State-certified hazardous waste testing laboratory, and analyzed for metals arsenic, lead, and mercury, and organochloride pesticides using EPA Methods series 6000/7000 and 8080. • The known well and any other wells discovered at the site should be properly destroyed through the SJCEHD,provided that the well(s)will not be used. The current use of the project as a water-treatment facility does not warrant additional `- investigation and/or environmental testing, unless the site will be zoned for residential housing and/or public school use. If re-zoning aces happen, then exploratory trenching should be conducted in the immediate vtemtty of the-'mass III disposal site: If significant staining, odors or other environmental precursors are identified, then soil and groundwater samples must be collected for analysis. Selected soil and groundwater samples will be analyzed for total extractable petroleum hydrocarbons (TEPH), total oil and grease (TOG), volatile organic compounds (VOCs), semi-volatile organics (SVOs) and CAM 17 metals using EPA Methods TERRASEARCH, inc. Page 9