Hazardous Waste Site Management Water Quality Issues (1988) / Chapter Skim
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RAPPORTEURS' REPORTS
RAPPORTEURS' REPORTS
Pages 177-194
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From page 177... ...
. What is the ability of existing methods to account for diverse conditions?
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From page 178... ...
4. Setting the standards by risk analysis to quantify the magnitude of the hazards and then by setting risk goals.
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From page 179... ...
a miscellaneous category consisting of defensibility, residual risk, and others. The first criterion refers to whether the goal is being accomplished and if so, whether it is being accomplished at the least cost.
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It is simply not feasible to rely on undocumented expert judgment in a highly emotional area with many different levels of control and cleanup available at very different cost levels. Thus, risk assessment and goal setting have emerged as the prime approach to standard setting by default rather than through an attractive display of the strong properties of this approach.
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From page 181... ...
Finally, some researchers have attempted to examine the safety implications of decisions made by federal regulatory agencies. The agencies had no explicit safety goals and instead agonized over each decision individually.
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From page 182... ...
There has been some validation, but first, one must understand that all current risk assessment techniques are attempts to derive reasonable upper bounds to the risk level. They are somewhat analogous to "probable maximum floods." Thus, validation does not consist of asking whether the risk estimates are accurate indicators of what is found in epidemiological investigations.
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From page 183... ...
HYDROGEOLOGY WORKSHOP Rapporteur: James W Mercer After discussing the colloquium papers the workshop group summarized the role of hydrogeologists in hazardous waste site management.
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They include direct measurement, ground water modeling, theoretical calculations, and expert opinion. Direct measurement includes tools and techniques normally associated with site characterization such as siting, drilling, and installation of monitoring wells; sampling ground water; and chemical analysis of those samples.
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From page 185... ...
For example, in a ground water modeling application, multiple simulations may be required in which both sensitivity analysis on uncertain parameters and scenario analysis on uncertain conditions are performed. ASSOCIATED DATA BASE As indicated throughout this discussion a major problem with all methods is the data or rather, the lack of it.
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From page 186... ...
Conway The formal presentations at the colloquium emphasized the aspects of toxicology, hydrogeology (transport/transformation) , regulatory strategy, economics, and public concerns in setting cleanup levels at hazardous waste sites.
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From page 187... ...
. In this figure the cleanup goals that is, the site-specific levels of acceptable exposure or risk-are established by comparing release concentrations with background levels; exposure concentrations with accepted concentration standards for chemicals in the various media; and the risk level with policy goals for acceptable risk.
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From page 188... ...
-1 1_' 1 ( a ) Dashed 1 i nes i ndicate PersDeCtiVes of some Site-Specific Acceptable environmental groups Exposure or Risk Levels and regul atory agencies (b)
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From page 189... ...
Another observation of participants in the engineering workshop was that remediation systems cannot be reliably designed for very low standards because design relationships are not proven down to those levels. Also, analytical methods with "practical detection limits" that is, reasonable detection levels based on available analytical technology, considering economic and technical feasibility at or below the proposed cleanup standards are needed for proper evaluation.
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From page 190... ...
CONCLUSIONS Engineering solutions that are cost-effective should be discussed early in the process of setting water quality standards; that is, in selecting a method for dealing with a particular hazardous waste site, consideration should be given to achievable engineering solutions.
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From page 191... ...
Designs should be pointed toward rugged concepts that are of a safe/faiT perspective rather than a fragile design in which failure can result in serious consequences. ~ Engineers should take a leading role in helping to inform the public and in some cases regulatory staff of the reliable engineering aspects of hazardous waste site management and water quality issues.
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From page 192... ...
One of the weaknesses of trying to calculate risk is that many toxicants singly or in combination-have not been evaluated for their health effects; thus, the total exposure from air or water, or to the skin, for present or future users of the land and water is difficult to estimate. Consequently, many believe a negotiated technical solution to pump and treat ground water to the level of surface water resources is the most practical and the quickest way to confine the ground contamination.
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From page 193... ...
a great frustration with the congressional mandate to clean up to background levels, and they believe that in 5 more years there will be great disappointment with the slow rate of such cleanups. They think much of the effort must be made by technical people to educate Congress and the public in general as to what can be done with the available funds; they also think it is necessary to convey how impossible it is going to be to achieve original or background levels at all major sites.
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