Laserfiche WebLink
Review of OU-1 FS Report -5- 7 August 1992 <br /> DDRW, Tracy <br /> Resolution 68-16 <br /> The Draft OU-1 FS Report states that it is doubtful that the Resolution 68-16 (Non- <br /> Degradation or Anti-Degradation Policy) can be justified as an ARAR, but is more <br /> reasonably considered as a To Be Considered (TBC) Requirement (page 2-5) . We <br /> disagree with this statement. Resolution 68-16 is an ARAR. This ARAR is a <br /> narrative standard which was adopted by the State Board to satisfy the Federal Clean <br /> Water Act anti-degradation policy requirement. Resolution 68-16 does not allow <br /> water quality to be degraded below what is necessary to protect beneficial uses. <br /> Therefore, this policy would be a chemical- and action-specific ARAR. How this ARAR <br /> applies will be a site and constituent specific determination (refer to Comment <br /> No. 7 above) . We have attached a legal memorandum from the State Board regarding <br /> the application and implementation of Resolution 68-16. <br /> Constituents of Concern <br /> We concur with the proposal in the Draft OU-1 FS Report to not consider dieldrin, <br /> arsenic, boron, and nitrate as chemicals of concern for OU-1. Because treatment of <br /> these constituents would not be the same as for VOCs, because on-site source areas <br /> have not yet been confirmed and because these constituents may be regional <br /> background concentrations, it would be premature to include these constituents in <br /> OU-1. Should it be determined that these are constituents of concern, they should <br /> be included in the site-wide RI/FS. <br /> However, elevated concentrations of dieldrin, arsenic, boron and nitrate may present <br /> a problem with disposal of the treated ground water whether or not these are <br /> constituents of concern. Because of Resolution 68-16, we cannot approve the <br /> discharge of treated ground water with elevated concentrations of these constituents <br /> to another water body of better water quality unless it is in the public interest <br /> and is at levels below water quality standards. Therefore, prior to implementation <br /> of the final ground water remedial action, Tracy will need to estimate whether the <br /> effluent from the final ground water remedial action will have elevated <br /> concentrations of these or other constituents, such as general minerals. Once the <br /> IRM begins (re-start tentatively scheduled for September 1992), Full Scale Operation <br /> monitoring as required by WDRs No. 90-275 must be conducted to supply this <br /> information. In addition, we request that analyses for all general minerals be <br /> conducted on influent and effluent samples. <br /> Aquifer Cleanup Duration and Aquifer Cleanup Level <br /> Cleanup of the aquifer is estimated in the Draft OU-1 FS Report to occur over a <br /> period of 30 years in order to achieve the proposed aquifer cleanup levels of 2.5 <br /> micrograms per liter (p g/1 ) for trichloroethylene (TCE) and 0.7 pg/l for <br /> tetrachloroethylene (PCE) . According to Resolution No. 92-49, the aquifer must be <br /> cleaned up to attain background if technically and economically feasible. If <br /> cleanup to background is not attainable, then alternative cleanup levels must be <br /> consistent with the maximum benefit to the people of the state and must meet water <br /> quality standards to protect existing and potential beneficial uses. <br /> Cost analyses must be developed for cleanup to background and for various other <br /> aquifer cleanup level scenarios (such as 5 pg/l for TCE and PCE) . The highest <br /> concentration protective of beneficial uses would be the concentrations of <br />