ARCHIVED REPORTS XR0010905 - Laserfiche WebLink

Home Browse Search

rim I 04 February 2000 AGE Project No. 95-0118 Page 6 of 7 � 3.5. ANALYTICAL RESULTS OF GROUND WATER SAMPLES Water samples from monitoring wells MW-2 and MW-5 contained TPH-g at concentrations of 56 micrograms per liter (,ugll) and 57 Ag/l, respectively. Samples from other wells had no detectable concentrations of TPH-g. The sample from well MW-5 contained benzene at a concentration of 1.2 ,ug/l. Other BTEX compounds were not detected in the wells on the site. Analytical results of ground water samples are summarized in Table 2. F- The laboratory report (MAI Lab ID 24159 to 24164), Quality Assurance and Quality Control (QA/QC) report and a chain-of-custody form are included as Appendix D. 4.0. CONCLUSIONS Based upon results of groundwater monitoring well sampling, AGE concludes =' The ground water elevation was at approximately thirty-five feet below surface grade. The hydrocarbon concentrations have decreased significantly since the previous monitoring event. This decrease may be due to the mechanical movement of the air through the ground r water or the overall movement of the dissolved plume away from the area of initial petroleum release. During the past three months of soil vapor extraction, an estimated 78.5 gallons of petroleum a as gasoline has been extracted.Benzene concentrations have begun to decline in the extracted vapor stream yet other BTEX compounds concentrations have remained at significant levels i = in the extracted soil vapor stream. �._.1 5.0. RECOMMENDATIONS Based upon the results of the investigation, AGE recommendations: c-s • Continue quarterly monitoring of ground water wells,with the next event scheduled for late February 2000. • Initiation of in-situ air sparging(IAS) in combination with the soil vapor extraction(SVE) remediation system currently operational on the site. Advanced GeoEnvironmental,Inc.