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hydrocarbon concentrations in the impacted soil are generally less than 100 ppm Furthermore, the data indicates that impacted soil is not encountered at depths more shallow than 20 feet. It appears that the impacted soil may be a result of fluctuating ' groundwater depths, creating a 10 to 15 foot "smear zone" at the site Several alternatives are available for remediation of impacted soil at the site Initially it is ' likely that the PHS/EHD will require feasibility studies or pilot tests for possible remedial methods, such as the performance of a soil vapor extraction test However, because of the relatively low concentration of petroleum hydrocarbons in the soil, other remedial methods ' should also be considered (i.e , bioremediation, excavation, etc ) ' 5.2 Hydrocarbon-Impacted CroundNtiater No petroleum hydrocarbons were detected in groundwater samples collected from MW-8 ' or MW-9, defining the northern and southern extent of impacted groundwater Only low concentrations of hydrocarbons were detected in MW-5 and MW-7 These wells are likely near the eastern and western extent of impacted groundwater Figure 5 illustrates the ' approximate limits of impacted groundwater at the site It appears that the lateral extent of impacted groundwater has been defined However, ' before remediation can commence at the site, the PHS/EHD will likely require performance of an aquifer (pump) test at the site Although not a recommended remediation alternative, "pump and treat" can be used for containment of the groundwater plume, should future sampling indicate that the plume is migrating beyond curient limits Data collected from the aquifer test will also provide ' important information on aquifer chaiacteristics if a pump testis required, we ieconimend the installation of an extraction %yell near the center of the impacted groundwater plume ' 6.0 LIMITATIONS ' Our professional services were peiformed using that degree of care and skill ordinarily exercised by environmental consultants practicing in this or similar localities The findings ' were based upon analytical results piovided by an independent laboratory Evaluations of the geoiogic/hydrogeologic conditions at the site for the purpose of this investigation are made from a limited number of available data points (i e soil borings, monitoi ing wells) and ' subsui face conditions may vary away from these data points No other warranty, expressed or implied, is made as to the professional recommendations contained in this report Cmbgral wYde$e.v�+ � 11 ' SG94 09-10260211045 honw4mi QAUI:94 1