WORK PLANS - Laserfiche WebLink

Home Browse Search

INMAL RELEASE DDJC Tracy AgriIt ral Walla• Current and Future Exposures The three agricultural wells are no longer used for irrigation, and therefore, pose no current or potential future public health hazards. The wells have been abandoned to minimize possible contaminant transport to the Lower Tulare Aquifer through well casings or gravel packs. AG-1, AG-2, and AG-3 were sealed in September 1994, December 1994, and June 1995, respectively. In the area of the AG-2 pump, the groundwater flow subsequently returned to north-northeast (Montgomery Watson, 1995). No new agricultural wells are likely to be installed in the area because California legislation allows regulatory agencies to prohibit drilling new wells within 2,000 feet of a hazardous waste site boundary. No public health hazards are associated with exposure to contaminated groundwater located beneath DDJC Tracy or in off-site areas. Site-related contaminants have not been detected in on-site water supply wells, the Tracy municipal water supply, or nearby private wells at levels that might result in adverse health effects. Contact with On-Site Surface Soil Day Care Center Play Yard Approximately 90 children attend the Day Care Center located in the northwest corner of the site. Children play in the center's 0.5 to 1 acre yard that is mostly covered with grass; however, there are areas of exposed soil. A former underground storage tank(LIST), which contained No. 2 fuel oil, was partially located within the play yard. The tank and surrounding soil were removed in 1988 (DDJC Tracy, 1997a). In 1994, DDJC Tracy collected five surface soil samples from within the play yard. The sample locations were selected to represent exposed soil areas commonly used by children. The soil samples were analyzed for semivolatile organic compounds (SVOCs), metals, and pesticides and the results are presented in Table 6. Although several contaminant concentrations (i.e., arsenic, chromium, vanadium, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene [DDEJ, 1,1,1-trichloro-2,2- bis-(p-diphenyl)ethane [DDT], and dieldrin) exceed ATSDR's very conservative comparison values for pica behavior (frequent hand-to-mouth activity), most values are typical of regional background soil concentrations (Montgomery Watson, 1995). Lead was also detected in three of five surface soil samples at a maximum concentration of 20.3 parts per million (ppm). Although a comparison value has not been established for lead, ATSDR determined that the soil lead concentrations are much lower than levels that have been shown to contribute to elevated blood lead level in young children who might incidentally ingest soil (CDC, 1991). DDJC Tracy has since removed the top 1 foot of soil from the entire play yard and play box material and replaced 13