SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Al Jesena - 2 - 1 March 2000 Draft RI for OU#3 NCTS, Stockton ■ "The total dissolved solids (TDS) exceed 3,000 mg/l (5,000 µmhos/cm, electrical conductivity) and it is not reasonably expected by the Regional Water Board [for the groundwater] to supply a public water system." Current average TDS values equal 2500 mg/1 based on all monitoring wells at the facility. Nevertheless, background water quality data has yet to be developed at the facility. Once background concentrations have been established, TDS and metal concentrations in groundwater may be compared to background to assess potential impacts at specific sites and to evaluate this criteria. Therefore, a special study to evaluate potential remedial actions may be preliminary at this time. ■ "There is contamination, either by natural processes or by human activity(unrelated to a specific pollution incident), that cannot reasonably be treated for domestic use using either Best Management Practices or best economically achievable treatment practices." The Navy refers to the non-petroleum hydrocarbons that have been detected in soil as motor oil, gasoline, and diesel range organics. As discussed in our comments below entitled Total Petroleum Hydrocarbons in Soil, we do not concur with the Navy's conclusions that these organics are naturally occurring. Further research and documentation are warranted. ■ "The water source does not provide sufficient water to supply a single well capable of producing an average, sustained yield of 200 gallons per day." The RI report states that 24 hours was required to extract 15 gallons of water from Confining Unit 1 during purging for groundwater sampling. According to the hydrogeologic study, the Shallow Water Bearing Zone (Confining Unit 1), Aquifer 2, and Aquifer 3 are hydraulically interconnected; therefore, we question the Navy's statement that Confining Unit 1 "does not meet the 200 gallons per day requirement for agricultural usage" (Goal GM-5). As part of the Groundwater Management Approach, the Navy focuses on containment of groundwater or designating the sites as non-attainment zones. First, it is unclear whether or not the Navy understands what is required with respect to obtaining approval for a non-attainment zone. The Navy does not provide any remedial investigation alternatives in support of this option nor do they discuss a feasibility approach in support of this designation. Secondly, there is no active remedial alternative recommended that could provide a positive cleanup effort of the landfill sites. The Navy should evaluate all possible alternatives with associated technologic and economic viability of each in the feasibility study. In order to support this effort, the Navy should include an analysis of the data that supports active remedial alternatives and not just focus on containment and/or a non-attainment zone.