ARCHIVED REPORTS_XR0005143 - Laserfiche WebLink

Home Browse Search

2.5 Assessment of Hydrocarbon Impacted Groundwater It is our understanding that prior to January 1995, groundwater samples from the site had been collected on three occasions. During each sampling event, free hydrocarbon product was detected in MW-1, therefore, no samples were collected. Petroleum hydrocarbons have ' also been detected in samples from MW-3 and MW-4 during each sampling event Well Point samples (hydropunch) collected by SEACOR indicate that hydrocarbon impacted groundwater may extend southwest off-site nearly 200 feet However, no monitoring wells ' are located down-gradient of MW-3 2.6 Aquifer Testing A pump test was performed at the site by SEACOR Groundwater was extracted m MW-1 and drawdown was measured in three surrounding wells The test duras onf was apprommately 24 hours SEACOR concluded in the PAR that drawdown data collected during the pump test Iindicated that the pumping from MW-1 has little influence at the site Therefore, a pump and treat system of groundwater remediation would likely be ineffective at the site Complete pump test data was included to the PAR 27 Vapor Extraction Test On June 10, 1994, SEACOR conducted a soil vapor extraction test at the site A vacuum was applied to an extraction well (VW-1) and measurements of flow rate and vacuum w collected fiom three temporary observation wells (VW-2, VW-3 and VW-4) However, a ' vacuum could not be achieved on VW-1, so the internal combustion (IC) unit was connected to one of the obsenation wells It appears that VW-1 may have been placed too close to the western UST excavation, which was backfilled with pea gravel, and "shoe t circuited" the attempt to draw a significant vacuum Despite the short circuiting of VW-1, SEACOR concluded that vapor extraction would be a viable remediation alternative for impacted soil at the site The data collected during the pilot test indicated that sufficient flow and hydrocarbon recovery rates can be achieved at the site 2.8 Additional Investigation Because of the inconclusive results obtained by SEACOR duringthe vapor representatives of the PHS/EHD indicated that a 24-hour soil vapor a tract on/n-s to aitr spa'91ng pilot study should be perfol need Installation of additional extraction and sparging wells would also provide additional soil and groundwater data for preparation of a FRP 6-1.1-1 A.&S.—I.e. ' CK'%P[W FRPn 951SC 94 12 1o5602 3