ARCHIVED REPORTS_XR0008774 - Laserfiche WebLink

Home Browse Search

r • Working To Restore Nature Composite soil samples collected from the stockpiled soil contained non-detectable to moderate levels of petroleum hydrocarbons Analytical results of soil composite samples are summarized in Table 1 Laboratory data sheets and chain-of-custody documentation are presented in Attachment 2 Other Site Activities Subsequent to the discovery of an oily liquid substance in the storm drain inlet and piping Roto- Rooter was contracted to clean the storm drain piping using a water betting tool Approximately 700 gallons of sludge and liquid removed from the storm drain system was contained in DOT certified 55 gallon drums which were labeled and remain on-site pending proper disposal During confirmation sampling activities on November 12, 1993, the eastern sidewall of the excavation collapsed under its own weight Monitoring well MW 1 was partially contained in the collapsed sidewall Recent rains had apparently destabilized the excavation's sidewalls Approximately 14 feet of casing remain in the ground CONCLUSIONS • Field observations and analytical data indicate that vertical migration of hydrocarbons through the soil has not exceeded 17 feet below surface grade and that lateral migration was not extensive Analytical results of excavation confirmation samples indicate that all impacted soil has been removed Excavated soil should be treated on-site via aeration and subsequently backfilled into the open excavation, or as an alternative, impacted soil should be disposed of at an appropriate landfill and the open excavation backfilled with clean native and imported fill Laboratory analyses of water samples collected from site monitoring wells and the open excavation indicate groundwater hydrocarbon impaction is limited to the immediate vicinity of the former tank pit No analytes have been detected in water samples collected in downgradient well MW4, or upgradient wells MW2 and MW3, indicating groundwater underlying the site has not been significantly impacted The relatively low transmissivity of the soil types at the site impede the movement of dissolved hydrocarbons RECOMMENDATIONS Based on the analytical results of samples collected from the stockpiled soil, RESNA proposes remediation of the soil by on-site aeration with subsequent backfill into the open excavation Prior to backfilling, "representative sampling" of the remediated soil must be conducted to verify successful remediation PHS/EHD suggests that one sample per 25 cubic yards be analyzed for petroleum hydrocarbons However, recognizing that sampling larger soil volumes at this frequency would generate inordinate expense, RESNA recommends that the methodology 1500591SXR-0194 FNL 4