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or approximately 0.52 gal/minute. After groundwater recovered to >_90% of static water level, an additional column of water was retrieved; no floating product was observed in the bailer. RECOMMENDATIONS The results of the bail down tests indicated that it is unlikely there is 3.34 ft (original apparent thickness) of free-phase floating product in the shallow water-bearing soil formation beneath the site. It is more likely that the initial apparent product thickness was the accumulation of vapor condensate during the 2.6 years that the well was unattended. This hypothesis is based on the apparent thickness of product calculated during TEST III following two weeks time for product to reinfiltrate the well. If the apparent 1 in of remaining floating product does actually exist in the formation (based on TEST II and TEST III calculations), then active product recovery is not recommended because most active systems are only capable of reducing thickness to approximately 0.25 inch, and therefore, this approach would be cost-prohibitive. Furthermore, the accuracy of the depth recordings is ±0.3 in, which may indicate that there is less than 1 in of free-phase floating product on the shallow groundwater. Because of the documented concentration of dissolved-phase petroleum hydrocarbons in the groundwater beneath the site, it is our recommendation that this small apparent thickness of free- phase floating product be mitigated during groundwater remediation procedures. Further subsurface investigation should confirm the actual non-existence of free-phase floating product �- beneath the site. Sincerely; WALSH & ASSOCIATES, INC. ! No. 559 8f31;y,' Jeffrey A. Clayton, R.G. Senior Project Manager Jr cc: Mr. Harlin Knoll, REHS (SCEHD) ..'�wnyyW f.`.T� t& 9/17/93 168 -020.prr �(�( 3 & Associates. Inc, Fmircminc:nial S i .nlitii and Engineers