Risk management hazardous waste

Soil contamination was not perceived as a problem until the 1970s, when incidents in the U.S. and Europe (Love Canal, NY Times Beach, MO Lekkerkerk, the Netherlands) awakened public awareness about the serious threats posed to human health and the environment by abandoned or improperly managed hazardous wastes. In response to the growing public concern, the U.S., the Netherlands, and a number of other European countries started a systematic effort beginning in 1980 to identify potentially contaminated sites, assess the level of contamination, establish priorities for remediation based on risk assessment studies and gradually implement the required remedial actions. 

The purpose of this Report is to set forth the technical principles and framework for a comprehensive and risk-based hazardous waste classification system. In this context, waste is any material that has insufficient value to justify further beneficial uses, and thus must be managed at a cost. Hazardous waste is waste that can be harmful to biological organisms, due to the presence of radioactive substances or chemicals that are deemed hazardous, to the extent that it must be regulated. Hazardous waste excludes material that is simply useless (e.g., typical household trash). This work is comprehensive because it considers all hazardous wastes irrespective of their source.1... 

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... 

This Section discusses approaches to risk management that are used in protecting the public from exposure to radionuclides and chemicals that cause stochastic responses in the environment. Different approaches to management of stochastic risks are used for radionuclides and chemicals. An understanding of the two approaches, including their differences and ways in which these differences can be reconciled, is important in developing a comprehensive and risk-based hazardous waste classification system. 

A proper reconciliation of the radiation and chemical paradigms for risk management is important to the development of a comprehensive and risk-based hazardous waste classification system. In particular, the proposed waste classification system developed in Sections 6.2 and 6.3 of this Report is based fundamentally on the concept that an acceptable risk generally can be substantially greater than a negligible risk. This distinction is used to define different classes of waste that pose an increasing hazard. 

Section 3 has discussed issues of risk assessment and risk management for radionuclides and hazardous chemicals. These discussions provide important background information for the development of a comprehensive and risk-based hazardous waste classification system. 

Previous sections of this Report have discussed concepts, precedents, and technical information that are important to development of NCRP s recommendations on a comprehensive and risk-based hazardous waste classification system. This Section discusses selected aspects of this background information that are critical to establishing the principles and framework for the recommended hazardous waste classification system. The topics discussed involve technical aspects of risk assessment and issues of risk management. 

Development and implementation of the comprehensive and risk-based hazardous waste classification system presented in this Report would be facilitated by changes in the current legal and regulatory framework for managing radioactive and hazardous chemical wastes in the United States. A number of examples have been discussed previously in this Report and are summarized below. 

Development of a comprehensive and risk-based hazardous waste classification system, in which waste classes are defined in relation to types of disposal systems that are expected to be generally acceptable in protecting public health, would not obviate the need to establish waste acceptance criteria at each disposal site based on the characteristics of the site and engineered disposal facility and the properties of wastes intended for disposal therein. The primary purposes of a hazardous waste classification system are to facilitate cost-effective management and disposal of waste and effective communication on waste matters. 

Investigations of PCDD, and especially 2,3,7,8- tetrachloro-dibenzo-p-dloxin (2,3,7,8- TCDD), has led to major advances In environmental sampling and analysis. In toxicology, risk assessment, risk management, and waste treatment. Techniques used for dealing with dioxin contamination represent the most advanced procedures for hazardous waste cleanup. These advanced techniques were developed because of ... 

U.S. EPA s recommendations regarding stack emission tests, which may be performed at hazardous waste combustion facilities for the purpose of supporting MACT standards and multipathway, site-specific risk assessments, where such a risk assessment has been determined to be necessary by the permit authority, can be found in the U.S. EPA document on Risk Burn Guidance for Hazardous Waste Combustion Facilities.32 The applicability of the new standards has been demonstrated in the management of hazardous waste incinerators, whose performance was shown to clearly surpass the regulatory requirements in all tested areas.33... 

The significance of the exposure levels shown in the tables and figures may differ depending on the user s perspective. For example, physicians concerned with the interpretation of clinical findings in exposed persons may be interested in levels of exposure associated with "serious" effects. Public health officials and project managers concerned with appropriate actions to take at hazardous waste sites may want information on levels of exposure associated with more subtle effects in humans or animals (LOAEL) or exposure levels below which no adverse effects (NOAEL) have been observed. Estimates of levels posing minimal risk to humans (Minimal Risk Levels, MRLs) may be of interest to health professionals and citizens alike. 

Esparza RJ, Mahmood RJ, Sedman RM. 1991. Hazardous waste incineration a correlation of operating parameters with risk and emission rates. Waste Management. 11 163-170. 

Management and disposal of the wide variety of hazardous wastes has been aided by the development of waste classification systems. The term waste classification refers to broadly defined waste categories related, for example, to properties of waste materials, potential risks to human health that arise from waste management or disposal, or the source of the waste. Ideally, hazardous wastes in the same class should pose similar risks to human health and, thus, require similar approaches to safe management and disposal. 

The primary purpose of this Report is to present NCRP s recommendations on classification of hazardous wastes. The Report is directed at a multidisciplinary audience with different levels of technical understanding in the fields of radiation and chemical risk assessment and radioactive and chemical waste management. Anew hazardous waste classification system is proposed that differs from the existing classification systems for radioactive and hazardous chemical wastes in two fundamental respects. First, hazardous waste would be classified based on considerations of health risks to the public that arise from disposal of waste. Hazardous waste would not be classified based, for example, on its source. Second, the classification system would apply to any hazardous waste, and separate classification systems for radioactive and hazardous chemical wastes would not be retained. In the proposed system, waste would be classified based only on its properties, and the same rules would apply in classifying all hazardous wastes. 

Thus, NCRP intends that exempt waste could be used or disposed of in any manner allowed by laws and regulations addressing disposition of nonhazardous materials. However, waste that would be exempt for purposes of disposal would not necessarily be exempt for purposes of beneficial use as well. Exemption of materials that contain hazardous substances to allow beneficial use also should be based on considerations of health risks to the public. However, limits on the amounts of hazardous substances that could be present in exempt materials intended for a particular beneficial use could be substantially lower than the limits for disposal as exempt waste, due to differences in exposure scenarios for the two dispositions, and disposal may be the only allowable disposition of some exempt materials based on considerations of risk. In addition, exempt materials may consist of trash, rubble, and residues from industrial processes that have no beneficial uses and must be managed as waste. 

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