SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Tracy Well Survey -2- 28 December1995 RWQCB whether or not uninvestigated on-site waste management units may be sources of the CC14 ground water contamination. Board staff sampled domestic supply wells and monitoring wells in the Tracy area based on the following additional potential source areas for CCl4 ground water contamination: the All-Pure Chemical Co.; the Triple E Produce site; and the Lyoth Loading Station. Also as part of this survey, ground water monitoring data for VOCs detected during the survey period, reported by these sites and by DDRW Tracy, was also evaluated in conjunction with the data obtained from Board staff field activities. FIELD ACTIVITIES Ground Water Monitoring and Well Sampling Regional Board staff conducted a limited ground water sampling program during the last quarters of 1991 and 1992, and the first quarter of 1993. Although the duration of the program was planned through 1994, the field sampling activities were unexpectedly discontinued after March of 1993 because Regional Board field staff was no longer available. The wells sampled by Regional Board staff are shown on a location map in Figure 1. The sampling dates and analytical results are presented in Table I- Tracy Well Survey Results/Regional Board Sampling. ADDITIONAL GROUND WATER MONITORING DATA In addition to the ground water monitoring data obtained from survey field activities, Regional Board staff reviewed data reported from ground water sampling conducted during the survey period by Montgomery Watson, as part of the Well Monitoring Program for DDRW-Tracy(data presented in Table 2), by RESNA for the All Pure Chemical site (site maps illustrating monitoring well and production well locations in Figures 2 and 3, data presented graphically in Figures 4 and 5 and listed in Tables 2 and 3), and by Weston for the Triple E Produce site (site map illustrating monitoring well locations in Figure 6 and data presented graphically in Figure 7 and listed in Tables 2 and 4). LABORATORY ANALYSES All ground water samples collected by the Regional Board were analyzed using EPA Method 601/602 or EPA Method 8010/8020.' ' Laboratory is State certified for performing standard analytical methods.