ARCHIVED REPORTS_XR0006966 - Laserfiche WebLink

Home Browse Search

BlaaS Environmental Management Inc 3rd Qtr 2004 Groundwater Monktonng Report 002-70950-04 U-Haul#709-50 their respective p groundwater monitoring programs Analyses of groundwater samples from monitoring ' well MW-7C submitted by Blaes Environmental to Sequoia Analytical indicated TPHg at concentrations of 4,100ug/L and benzene at concentrations of 630 ug/L, which were significantly higher than those collected by GZA and submitted to Argon Laboratories, which indicated TPHg at concentrations of 1,800ug/L and benzene at concentrations of 350ug/L As a result of this inconsistency, a Blaes Environmental representative returned to the U-Haul site on ' September 28, 2004 to purge and collect groundwater samples from monitoring wells MW-5C, MW-7C, and MW-8C to confirm the third quarter 2004 groundwater sampling results Monitoring wells MW-5C and MW-8C were selected for re-sampling as both are located at the perimeter of the U-Haul property and both generally exhibit groundwater sample results with low or no concentrations of petroleum ' hydrocarbons The groundwater samples collected from MW-5C and MW-8C in the third quarter 2004 indicated benzene concentrations of 1 1 ug/L and 70ug/1, respectively These results may be accurate due to uncharacteristically low groundwater levels across the site during the sampling period However, ' due to the difference in sample results returned from MW-7C, it is possible that the uncharacteristically high concentrations of hydrocarbon constituents in all monitoring wells is the result of cross contamination in one of the laboratories The new samples collected on September 28, 2004 from monitoring wells MW-5C, MW-7C, and MW-8C were sent to Del Mar Analytical of Irvine, California ' for the purpose of obtaining an unbiased result Analytical results of groundwater samples collected on September 28, 2004 support Blaes Environmental's original sample results provided by Sequoia Groundwater samples collected from monitoring well MW-7C indicated TPHg and benzene at concentrations of 3,500 ug/L and 410 ug/L, -- -- respectively Groundwater sample-results from monitoring wells MW-5C and MW-8C are similarly - ' confirmed The laboratory analytical report for the confirmation sampling event is included as Appendix D The highest concentrations of hydrocarbons m groundwater a the - " g y gr t U Haul site in the middle B casing wells are from wells MW-2B and MW4B Concentrations of Benzene and 1,2 DCA were below laboratory reporting limits in U-Haul's groundwater samples from monitor wells MW-8B, MW-IOB, MW-11B, and MW-12B Concentration contours and the approximate extent of Benzene and 1,2 DCA 9