WORK PLANS - Laserfiche WebLink

Home Browse Search

pumping is towards the west-southwest. However, the Oak Park well, which is located about 2,500 feet west of the site, and other CWS wells, also have high pumping rates. Pumping of the wells also appears to affect the direction of on-site groundwater--especially when CWS-77 is not pumping. Most of the municipal and agricultural wells in the area draw water from both the A and B aquifers (personal communication, Cam Williams, 1989) . As indicated in Table 1, elevated concentrations of VOCs and heavy metals were detected in samples from shallow and deep on-site groundwater monitoring and production wells drawing water from the A aquifer. The heavy metal concentrations, however, were detected in unfiltered samples only, indicating that most, if not all, of the heavy metals were adsorbed to solid particles (e.g. , silts) and were not in the dissolved form. However, that cannot be unequivocally determined until additional monitoring of newly installed on-site monitoring wells is completed. In addition, it cannot be determined if the B aquifer is affected by site-related contamination because no wells draw water solely from that aquifer. Currently, the on-site production wells are not being used for drinking or process waters (personal communication, Doug O'Neal, 1989) . From available monitoring data and information, it appears that the off-site CWS-77 well and the Oak Park well have been contaminated by VOCs from the site. It cannot be determined if the heavy metals detected in off-site domestic or municipal wells (Table 1) are site-related until on-site heavy metal contamination of groundwater is confirmed (personal communication, Cam Williams, 1989) . Several domestic wells near the site (i.e. , several hundred feet north of the site) were not sampled during the RWQCB sampling in 1987. Given the proximity of those wells to the site and the lack of information on the direction of groundwater flow, those wells, and any other domestic wells near the site, may be affected by site-related contamination. Consumable Biota There are no current, or indicated future, pathways in which wildlife could be exposed to site-related contaminants. As indicated previously, the area immediately surrounding the site does not support abundant wildlife and the site is fenced and operational -- limiting the potential for exposure of wildlife to on-site contaminated surface soils (sludges) . As indicated previously, several domestic wells near the site that may be used for potable or nonpotable purposes (i.e. , irrigation or watering livestock) were not sampled. Hence, it cannot be determined if livestock or consumable crops are being watered with contaminated groundwater. Air The potential exists for the generation of heavy metal-contaminated fugitive dusts (especially lead) from the on-site contaminated surface soils (sludge) . Most of the year, the on-site contaminated soils are covered with vegetation (some thickly covered) . Once a year, however, that vegetation is cut short to avoid the spread of fires. During that period, dusts are generated at the 8