SITE INFORMATION AND CORRESPONDENCE_FILE 2

Home Browse Search

i i Separate-phase hydrocarbons have not been detected throughelectronic conductance sensors used to determine the presence/absence of separate-phase hydrocarbons. • The presence of separate-phase hydrocarbons has not been indicated through the use of hydrocarbon reactive pastes and tapes used in ground water monitoring activities. Second Bullet Item Alton Geoscience disagrees that the review of remedial technologies in Appendix A is "completely inadequate for evaluating the feasibility and costs associated with the technologies." The implicit intent of any remediation technology is to reduce potential risks to human health in the environment. Therefore; the first step in determining theefficacy of remediation technologies should be to evaluate potential health risks associated with current concentrations i of chemicals in the environment. !'In acknowledging that virtually no site can be remediated to non-detectable levels of contamination, this review focuses on the applicability of several remediation technologies to cost-effectively address remediation. The potential remediation technologies presented in Appendix A are limited in their ability to completely remove all chemicals from the environment:' With this in mind, Alton Geoscience believes that each potentially applicable remedial technology should be evaluated with respect to its cost and its ability to completely remove all contaminants from the environment. Since complete removal of all chemicals from the environment is neither practical nor necessary to protect human health, Alton Geoscience suggests passive remediation and ground water monitoring for this site. In support of the selected remedial technology, the United States Environmental Protection Agency has recently endorsed a similar approach for a Federal Superfund site (Olin.Corporation Site, Burrillville, Rhode Island.) Third Bullet Item The passive remediation strategy, as proposed by Alton Geoscience, relies on natural processes . to remediate hydrocarbon-affected soil and ground water. The natural processes which affect hydrocarbon concentrations include biodegradation and volatilization. Section 2.4, Pages 2-3 and 2-4 First Bullet Item To test the Geomatrix argument,,Alton Geoscience has recalculated the ground:water velocity based on the comments generated by Geomatrix. Substituting the assumed hydraulic conductivity suggested by Geomatrix into the equation predicting ground water velocity yields a linear ground water velocity of approximately 98 feet/year. If this were truly more representative of actual ground water velocity at the site, measurable concentrations of petroleum hydrocarbons should have been detected in offsite, downgradient groundwater monitoring wells. Since such concentrations were not detected downgradient, this supports Alton Geoscience's j , i 10 7 r