Laserfiche WebLink
ASS O C I ATE S I N C . <br /> contained detectable concentrations of oxygenate fuel additives. The extent of impacted <br /> groundwater is shown on Figure 4. <br /> Analytical results of groundwater samples are summarized in Table 2. <br /> A� <br /> 6.0 CONCLUSIONS <br /> ' Analytical results for soil samples are generally consistent with field observations and PID <br /> readings. Based on the analytical results and field observations, the following conclusions can be <br /> ' made. <br /> • The lateral and vertical extent of impacted soil beneath the site has been essentially <br /> defined. <br /> • The soil impacted by petroleum hydrocarbons, approximately 200 cubic yards, has been <br /> ' removed by excavation. <br /> • The lateral extent of impacted groundwater beneath the site has been essentially defined. <br /> Impacted groundwater remains in the vicinity of the excavation. <br /> 7.0 REMEDIAL ALTERNATIVES <br /> Based on the results of previous investigations and interim remedial actions, ATC has considered <br /> several remedial alternatives to meet our cleanup goals to reduce concentrations in soil and <br /> groundwater. Remedial alternatives include: <br /> ' 4 Alternative 1 -Passive Remediation with Groundwater Monitoring <br /> to g <br /> 4 Alternative 2 - Groundwater Extraction and Soil Excavation <br /> 1 <br /> A summary of each alternative is presented in the following sections. <br /> 1 771 Alternative 1 -Passive Remediation with Groundwater Monitorin <br /> This alternative would involve no active remediation. Naturally occurring microbes which degrade <br /> ' petroleum hydrocarbon constituents over time would be utilized to gradually reduce concentrations of <br /> TPHd in the groundwater. Construction activities would continue as scheduled with appropriately <br /> trained personnel and the necessary precautions would be taken. Implementation would involve <br /> installing three groundwater monitoring wells and performing monitoring and sampling on a quarterly <br /> basis. Initial monitoring events would include sampling for bioremediation parameters to evaluate the <br /> rate at which petroleum hydrocarbon constituents would be reduced. Samples would be analyzed for <br /> W:\92254\SumMtdm 6 <br />