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total of approximately 104 extraction and rein- groundwater plume. Residences over or <br /> wellsjection ,and 5 rec� g' culatin wells. downgradient of the plume have beer <br /> scheduled to be connected to public Ovate <br /> Matrix CriteriaThere may not be adequate controls on <br /> Overall Protection of Human <br /> Health and the wells. <br /> Environment: Under this alternative,human health Effectiveness of Treatment Systems: <br /> would berotected because a high percentage of the portion of the treatment system is ca <br /> p p . <br /> groundwater plume is captured, further migration of removing VOCs and EDB to below detects <br /> contaminants is greatly reduced, and institutional ether contaminants, such as semi-vola <br /> controls will minimize future exposure to contami- inorganics, would also be treated to ba <br /> ts. Institutional controls include prohibiting levels, if technically and economically f� <br /> nan <br /> in of new wells within, or in the direct path of, the appear <br /> in the extracted water <br /> drilling Y pp <br /> the CS-14 groundwater plume. Most of the plume recirculating wells remove only VOCs ani <br /> that might otherwise migrate under or into Ashumet effectively remove EDB, semi-vola <br /> and Jahns Ponds would be captured. Contaminant inorganics without additional abol <br /> concentrations downgradient of the system south of processes,which are not included in this a' <br /> Sandwich Road are reduced by recirculating wells. These contaminants are not anticipate <br /> _ vicinity of the recirculating wells. If EI <br /> Hydrological thresholds, such as minimizing draw din the <br /> ' minimizing the volatiles, or inorganics are detected <br /> dawn in surface water bodies and g <br /> levels requiring action, additional treatmex <br /> amount of treated water that flushes through the <br /> been met. This would re uire would be added. <br /> ponds, have not q <br /> design improvements to redistribute reinjected water Spent carbon produced by the system <br /> r <br /> aloe the ro osed rein ecton fences. Extensive <br /> g p p j i transferred offsite for regeneration, whicl <br /> construction would affect sensitive habitats and rare the contaminants. Residual solid wastes <br /> upland animal species. Impacts to Ashumet. Pond transferred offsite and disposed of in an a <br /> # habitats would be reduced by using recirculating manner. The residual solid wastes are no <br /> ## would require mod- Risks tc <br /> .wells. The remaining impacts wo q to be a hazardous waste. <br /> erste mitigation. associated with handling, treating, and di <br /> 'j <br /> ind residuals would be low. The alternative <br /> { Compliance with Applicable or Relevant a <br /> riate Re uirements This alter- statutory preference for treatment as a <br /> Approp q <br /> complies with all ARARs. element, <br /> native <br /> Response Alter- Implementability: Full system startup wi <br /> Effectiveness and Permanence of <br /> summarizes fume by the EPA-enforceable milestone of June <br /> natives: The table on page 3 plume <br /> capture by mass for all al terns <br /> fives. Asimilar table Partial system startup may be aehievab <br /> summarizing plum <br /> volume is included in <br /> Sandwich Road extraction fence in les <br /> e capture by <br /> • months from the decision date, given fu <br /> the matrix document <br /> regulatory approval. It is estimated that I <br /> Under Alternative F. 99 percent of the contaminantswill operate for at least 50 years. E <br /> (by mass) captured by the treatment system or <br /> accepted, proven technology that can be e <br /> caught in silts. . The system effectively removes <br /> perform reliably with proper mE <br /> contaminants, and the configuration would have a Recirculating well technology is used <br /> Re g gY <br /> minimal effect on other plumes. A small percentage contaminant mass removal south of Sand <br /> (I percent) of the contaminant mass would not be TR is a raven technology, <br /> Because E p <br /> captured or caught in silts; however, human health agency <br /> involvement to obtain approv <br /> and ecological risk associated with that portion is <br /> minimal. <br /> very low. <br /> Most of the ETR wells would be installe( <br /> Socioeconomic impacts associated with the <br /> property, greatly simplifying access <br /> uncaptured portion of the plume, such as impacts on locations. Recirculatingwells, however, <br /> commercial or residential interests recreation and <br /> 5 installed on private property between <br /> historical and archeological sites, are expected to be Road and Ashumet Pond. Because r <br /> low. Institutional controls will prohibit drilling of wells are somewhat less intrusive than <br /> new wells within, or in the direct path of, the CS-10 . <br /> 12 <br />