Waste-Disposal Situation

For classification and evaluation of residues, the following questions must be answered  

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To the extent that risk is used as a basis for waste classification, it is not used consistently. Different values for acceptable risk are assumed for different hazardous waste disposal situations. In addition, a variety of surrogate measures (e.g., ingestion toxicity, total radioactivity) having varying relationships to risk have been used to classify wastes. 

The International Atomic Energy Agency organized a series of interlaboratory comparisons for calibration purposes. Those completed so far include two seawater, one seaweed Fucus vesiculosus), and one sediment sample. These materials were contaminated in nuclear waste disposal situations and, in consequence, contain transuranic elements in concentrations much higher than those found in samples contaminated by global fallout of nuclear weapons testing debris. Nevertheless, the data speak directly to questions of calibration of detectors and yield... 

In practice, a combination or sequence of treatment methods may be needed to arrive at an acceptable quality of effluent and a viable waste disposal situation. The choice of method will depend critically on the nature and volume of effluents which must be dealt with, the regulatory demands on final effluent quality, and the constraints upon disposal of the sludges and spent materials which are an inevitable product of treatment processes. 

This paper provides a detailed overview of the current plastics waste management situation in Japan. It discusses material, chemical, and thermal recycling, and incineration versus landfill. It also provides a flow sheet showing recycling and the treatment/disposal of plastics waste in Japan in 1991. Conclusions are drawn, and the outlook for the future is considered. 5 refs. 

In extreme situations, incompatibility between injection fluids and reservoir components can be so great that deep-well disposal will not be the most cost-effective approach to waste disposal. In other situations, such remedial measures as pretreatment or controlling fluid concentrations or temperatures can permit injection even when incompatibilities exist. In addition to operational problems, waste-reservoir incompatibility can cause wastes to migrate out of the injection zone (casing/confining-layer failure) and even cause surface-water contamination (well blowout). 

Of course in some situations of exposure to chemicals, such as around waste disposal areas or chemical factories, exposure is to a mixture of possibly many different chemicals. These may interact in a variety of ways (e.g., additivity, synergism, antagonism, potentiation, see above). 

The best example of this is wastes that are classified based solely on the nature of the generating process or facility e.g., high-level radioactive waste, chemical wastes from certain industries), irrespective of the content and concentration of hazardous substances. This results in resources being used unnecessarily on lower-risk situations when they could be better applied to higher-risk situations (hazardous waste disposal or otherwise). For example, billions of dollars have been spent in managing... 

Dose-Response Assessment. Determining the relationship between the dose of a hazardous substance and the probability of a specific response is called dose-response assessment.6 This aspect of risk assessment is needed to extrapolate from responses observed in experiments or incidents involving high doses to the much lower potential doses relevant to waste disposal and other routine exposure situations. Dose-response assessment is a major issue in establishing the foundations of a risk-based waste classification system, and it is discussed in detail in Section 3.2. 

The doses of hazardous substances at which responses can be observed in humans or animals are higher (sometimes by large factors) than doses relevant to waste disposal and other routine exposure situations. Therefore, most dose-response relationships at the low doses of interest in protection of human health are calculated rather than measured they are based not only on scientific data but also on various assumptions and extrapolation models which, while scientifically plausible, cannot yet be subjected to empirical study... 

In its recommendations, IAEA emphasizes that waste classification, even if it focuses on waste disposal, does not provide an adequate substitute for site-specific safety assessments of particular disposal systems to ensure the acceptability of waste disposal. IAEA also recognizes the role of national authorities in implementing waste classification systems and ensuring the safety of waste disposal, and that different countries may choose to classify waste in different ways depending on their particular situations. However, IAEA believes that, if for no other reason than to facilitate communication, it would be desirable to achieve some level of uniformity of waste classification systems in different countries. IAEA recommends that it is particularly important to obtain an international consensus on the boundary for determining unconditionally exempt material that may be transferred from one country to another, especially for purposes of recycle/reuse. 

The option for disposal of potentially explosive materials is to have it detonated under carefully controlled conditions. Some laboratories and industries may have personnel trained in explosive handling, and they may be able to remove and detonate the material on their site where no damage will result. Alternatively, some contract waste disposal firms have the capability to remove and dispose of explosive material. It also is possible to make arrangements with a local squad who handles explosives (or even a fire department) to collect, remove, and detonate the material under safe conditions. In all situations, the chemist should provide the disposal expert with whatever information is available on the hazards of the chemical(s). 

Laboratory managers are responsible for establishing waste disposal procedures for routine and emergency situations, and for communicating these procedures to laboratory workers. Workers must follow them to avoid hazards or damage to the environment. 

In a waste disposal site evaluation, the hazard identification step will involve collecting and validating all recorded and other information on the nature and properties of the wastes actually in a site. The purpose is to determine whether a hazardous situation actually exists. Stated simply, is there a potential for harm to health and the environment when considering the materials present ... 

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