ARCHIVED REPORTS XR0009205 - Laserfiche WebLink

Home Browse Search

' eolo ua(Technus 7nc � g Page 3 Groundwater Monitoring Report Project No 723 2 September 13,2000 1 Extreme care was exercised while transferring the sample into 40-m1 VOA vials preserved ' with hydrochloric acid All samples were checked for headspace bubbles, labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory The sampling technician while collecting all samples wore disposable gloves A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from field to the laboratory, thereby providing a means to track their movement and ensure their integrity ' 1.3 Laboratory Analyses The groundwater samples collected on August 29, 2000 were delivered to Sherwood Labs of Hilmar, California(certification #1400) for analysis of • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by method EPA method 602 ' • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) • Fuel Oxygenates (MTBE, DIPS, ETBE, TAME & TBA) by EPA method 8260B The detection limits for the above analyses are listed in Table 2 of Appendix A, while the lab analytical results are presented in Appendix B 20 FINDINGS AND DISCUSSION The results of the groundwater sample analysis show the following • BTEX and TPH-G concentrations continue to fluctuate in the monitoring wells ' • MW-101 showed low levels of BTEX and decreasing TPH-G for the fourth consecutive event This well was installed in August 1999 through the upper, heavily contaminated zone of soil and groundwater GTI has observed that deep discretely screened wells drilled through contaminated soil will typically test positive for contaminants due to ' contaminated soil and groundwater being dragged down the borehole during drilling This drilling artifact usually dissipates within a few months of the drilling and any ' contamination that is present long term is considered to be a portion of the larger groundwater plume • MTBE was detected in well MW-5 at 1100 ug/1 None of the other wells contained this ' compound, however the lab, due to the high levels of BTEX and TPH-G that are present in the groundwater samples, raised the detection limits • The domestic well DW @ 60 East Castle did not contain contaminant concentrations above the laboratory limits for the second consecutive event The well had previously contained trace amounts of Toluene and Xylene and low levels of TPH-G 1 1