ARCHIVED REPORTS XR0006771 - Laserfiche WebLink

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John Pestana QTIP Trust At Page 5 Figure 3 depicts the extent of capillary soil contamination Three well defined areas of contamination are evident at the site 1) Gasoline contamination beneath and downgradient (north-northeast) of the former product lines, 2) Gasoline contamination in the vicinity of and downgradient from the former USTs, 3) Hydraulic oil in the vicinity of the former waste oil UST In addition, a zone of commingled capillary soli contamination is evident at the north end of the property In this area contamination from on-site gasoline sources is mixed with contamination by longer chain hydrocarbons, apparent as a result of off-site pipeline leak(s) RECOMMENDATIONS Based upon the analytical results of soil samples collected at the site, which suggests that little or no residual contamination remains in vadose soil, Ground Zero recommends no further action be performed at the site with regard to vadose soil Due to apparent contribution to capillary soil and groundwater contamination from off-site source(s)to i the north (downgradient of onsite source areas), we do not recommend any additional investigation of the downgradient extent of groundwater contamination The gasoline hydrocarbon contaminants present in capillary soil and groundwater are expected to be amenable to natural biodegradation as has been amply demonstrated at numerous sites throughout the State Other natural attenuation processes such as sorption can be expected to be operative as well Contaminant concentrations in groundwater at the property have decreased from the levels present in 1991-92 and appear to have stabilized Figures 4 and 5 depict gasoline and benzene concentrations over time in wells MW 1 and MW2 Groundwater analytical results are summarized in Table 2 Oxygenate fuel additives, which may have a lower potential for natural attenuation, have not been detected in groundwater at the site(Table 2) Ground Zero recommends adopting natural attenuation as the corrective action at the site Groundwater monitoring wells should remain on their current annual sampling schedule to monitor and demonstrate the stability of dissolved petroleum hydrocarbon concentrations CERTIFICATION Signature of this report certifies that Ground Zero's professional services have been performed, our findings obtained, and our conclusions prepared in accordance with customary principles and practices m the fields of environmental science and engineering Items identified in the Scope of Work have been properly investigated and any samples collected containing Hazardous Substances have been disposed of in accordance with all applicable federal and state environmental laws and regulations pcstan&0361sumrpl doc