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U questio,able reliability of the models themselties, especially in the absence of a conramtnation tire, there is need tor an alrernatitr boundary history for cahbrarion purposes if the problem is approach in the re either regulators, in nature or a first-order assess- provided that the alto tlaco l�e�o 1pl Wince bonce dund Ment of a potential hazardis adequately protects the ground water Such an an compelling reason to seek some alternarne to, the approach need not provide for an e\act pre�3tction complex transport analysis This latter statement °f concentration Ie�els (which is the role at the reflects the recent trend in dck lattenc of complex trans standards for waste disposal sites which Favor the P Port analysts), but should address th question of vvhether or not minimum performxnCec establishment of minimum ;,��1e1`els are achieved In addition, the methodology as opposed to detailed operational requiiremen s should focus on parameters Which embody (CIark and Sabel, 1980 atial and relevant ody the ` temporal analysts of constituentsasprpovided b mechanisms operating i!7 a h droa environment and for which data are eadrly ova lahle transport models would a y Yet another concern is that man p appear to be cYcessive to derail if one is interested onlyy evaluators wt1I not possess strong technicsl backgrounds in the performance as might be expressedirh ouQ area of transport, so that complicated mathematics acceptable u bh some have to be avoided p Feer limit of concentration 0taximum concentration levels �[ This does not Preclude the use (1 CL's), as Proposedof more sophisticated techniques If the need arises, Environmental Protection Agency by the e the or if the technical skills and data base are avails standard example of an acceptable upper limit of available For the alternative boundary analysts, some contamination sort of gr- ound-water modeling is required Three If regulatory procedures arc to be based on different levels of models are available for this some minimum performance standard, such as Purpose The first and simplest lei el is provided MCL's, one of the critical decisions is the bounds by predicted average values of contaminant levels, at which COMPliance must be demonstrated Two with some form of dilution being provided b Possibilities exist the solid waste boundary or mixing with uncontaminated water Although the f some ce alternative the boundary at some specified employment of average values enormously reduces distance from from tht waste bo at � with currently accepted procedure, monitoring accordance the computational problerris, they use to a re�ulato y are of limited L the solid waste bounds t b ry scheme that is designed to ` boundary serves the useful purpose monitor maximum concentration levels Hence, as Of providing an accurate nationwide inventory o f Will be discussed shortly, average value calculations ` "open dumping" and "sanitary landfills " are useful mainly as a screening mechanism for the reliabilrry of such an overdue inventoryndeed, evaluating the di]upCon potential for w requires a common rneasurtn prior to intensive investigations rite sites and the waste boundary uniquely g Point far all facilities, The second level of sophistication is requirement lye u v satisfies this rationally no more complex than the first e p rPoses of inventory, however, compu- differ markedly from the purposes of monitoring, -tcept which in this case o to assure that ground water that it is presented as a solution to a fore boundary value problem This Solutio,i anstivers is not transmitting contaminants to the public domain in y raised in excess of those quantities s ecifted �vO critical questions that are a an environmental assessment of waste ltransport some minimum performance standardThefo Ana (1) When will the ivaste arrive at a specific location of inventory points of measurement to act as i e , t e a ternative oun ary' {:)) Flow much of the ! monitoring points for purposes of defining com li- max�rnuiri concentration level inventoried at rhe ante may result in an unrealistic assessment of he waste boundary will a ear at the threat of contamination This is due largely to Unfortunately, certain appear point these, focusing the monitoring activities bertaeen the Procedure, mainly rhe overall temporal ands ori first (engineered structure) and second variations that my spatial geologic environment) lines of defense, tile latter aht be eYpecred in a cornplek flow domain To provide answers to this question proL tdtng for important retardation and attenuating 1 requires ver a third level of s°pliiati�arton mechanisms Char would go unaccounted for in the a complex transport analysts This type of rnal analysis regulatory procedure Hence, the solid waste is beyond the sco e of boundary is a logical compliance point only where P this study and, in general, !) containment of the waste is 'a policy objective may not be a necessary requirement in a regulatory scheme that focuses on ground water protection Given that containment is not a viable alrerna- requirements b Eva 304 standards y y of minimum perrormance f �_ s