High-hazard waste determination

An important characteristic of acceptable disposal facilities for high-hazard waste is that inadvertent intrusion into a facility, such as by drilling, must be unlikely. Therefore, assessments of risk or dose to hypothetical inadvertent intruders based on exposure scenarios that are assumed to occur do not provide a suitable basis for determining acceptable disposals in facilities located well below the ground surface. 

Now you can reconsider the material balance equations by adding those additional factors identified in the previous step. If necessary, estimates of unaccountable losses will have to be calculated. Note that, in the case of a relatively simple manufacturing plant, preparation of a preliminary material-balance system and its refinement (Steps 14 and 15) can usefully be combined. For more-complex P2 assessments, however, two separate steps are likely to be more appropriate. An important rule to remember is that the inputs should ideally equal the outputs - but in practice this will rarely be the case. Some judgment will be required to determine what level of accuracy is acceptable, and we should have an idea as to what the unlikely sources of errors are (e.g., evaporative losses from outside holding ponds may be a materials loss we cannot accurately account for). In the case of high concentrations of hazardous wastes, accurate measurements are needed to develop cost-effective waste-reduction options. It is possible that the material balance for a number of unit operations will need to be repeated. Again, continue to review, refine, and, where necessary, expand your database. The compilation of accurate and comprehensive data is essential for a successful P2 audit and subsequent waste-reduction action plan. Remember - you can t reduce what you don t know is therel... 

A thorough inspeetion of equipment, whieh may inelude frisking or a wipe test, helps determine the duration of and methodology seleeted for deeontamination. All equipment parts should be eonsidered highly eontaminated, removed, and replaeed before the equipment leaves the worksite. Porous items (i.e., wooden truek beds, eloth hoses, wooden handles) usually eannot be thoroughly eleaned and should be disearded (as hazardous waste if neeessary). 

Polyethylene-based membranes are manufactured for use in hazardous waste landfills, lagoons, and similar applications. Two of these products have been tested to determine their effectiveness as barriers against radon diffusion. (In most cases, diffusive flow is considered of little or no significance as a mechanism of radon entry compared with convective flow). A 20-mil high-density polyethylene tested 99.9% effective in blocking radon diffusion under neutral pressure conditions. A 30-mil low-density polyethylene tested 98% effective in blocking radon diffusion under neutral pressure conditions. 

Studies of workers exposed to high levels of chlordecone indicate that pleuritic chest pain was a relatively common complaint (Cannon et al. 1978 Taylor 1982, 1985). Examination of workers with this complaint revealed no cause for the pains. Since oral exposure studies in animals did not identify any respiratory end points that may have been affected following ingestion of chlordecone (Larson et al. 1979b) and no inhalation exposure studies were located, a possible physiological basis for the workers complaints has not been identified. Insufficient information is available to determine whether persons exposed to low levels of chlordecone at hazardous waste sites would experience adverse respiratory effects, but the possibility cannot be discounted. 

For this reason, additional studies on carbon tetrachloride flux rates into and out of surface water, as well as refined quantitative estimates of aquatic fate processes would be valuable. The chemical is expected to evaporate rapidly from soil due to its high vapor pressure and may migrate into groundwater due to its low soil adsorption coefficient. No data are available on biodegradation in soil. Additional studies to determine degradation rates and the extent to which adsorption has occurred would be useful. These data are also useful in evaluating the impact of carbon tetrachloride leaching from hazardous waste sites. 

As discussed in Sections 3.2.3, 3.3, and 6.1, RfDs and slope factors are intended to provide conservative estimates of risk. Therefore, they are most suitable for use in establishing a negligible dose, i.e., in determining whether a waste could be classified as exempt. To reduce the amount of conservatism to a degree appropriate to establishing an acceptable risk for the purpose of evaluating whether a particular waste would be classified as low-hazard or high-hazard, RfDs are multiplied by a factor of 10 and the slope factors are divided by a factor of 10. 

These results indicate that alkalinity and the rate of release of alkalinity plays a major role in the release of heavy metals from stabilized/solidified hazardous wastes. The U.S. EPA EP-Toxicity Test is not adequate to evaluate the potential leachability of these wastes because the large buffering capacity of the fixed waste causes the extraction to be performed at a high pH where heavy metals are generally least soluble. It is important to determine the buffering capacity... 

It is often difficult to determine whether symptoms are related to a direct toxicological effect or to stress or worry. For example an investigation of a community living near a hazardous waste site in Queensland, Australia found no evidence of elevated levels of any serious physical disease but high levels of stress and anxiety.16 Odours may serve as sensory cues for the development of... 

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