SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

04/03/2000 16:39 209-579-222P MODESTO ATC PAGE 07 KOaVAM AR Working To Restore Nature 2. No BTEX analytes were reported in any of the groundwater samples. TPHd, however, was reported in groundwater from each Hydropunch sample collected. Groundwater monitoring wells were sampled on August 10, 1993. Well MW-4 was not sampled because of the presence of approximately 1.9 feet of free petroleum product. No BTEX constituents were reported in any of the groundwater samples collected. TPHd (84 ppb) was detected only in well MW-3. Results of laboratory analyses of groundwater samples are summarized in Table 2. Laboratory data sheets and chain of custody documentation are included in Appendix VT. Based upon groundwater monitoring data and analytical results collected to date, it is estimated that60o7 gallons of free product and 1.5 gallons of dissolved petroleum hydrocarbons exist in the saturated zone. These estimates are based upon the following assumptions: an aquifer thickness of 17 feet, an effective soil porosity of 20%, and an average free product thickness of 0.5 feet. The estimated areal extent of contamination in the groundwater is illustrated on Figure 8. 6.0 REMEDIATION ALTERNATIVES An initial screening of various soil and groundwater remediation alternatives was completed and each alternative was either retained or eliminated based on the applicability to the site. The following sections present potential applicable remediation alternatives for consideration. The relative merits and feasibility of these and/or other potential applicable remediation alternatives will be discussed in detail in a Site Remediation Workplan, to be submitted at a later date. 6.1 Soil The following soil remediation alternatives are discussed in this section: O Passive Remediation O "Hot Spot" Excavation O In-Situ Enhanced Bioremediation REP0RKr5/PAR1093.FNL 8