Waste, risk assessment

Risk assessment (i.e., calculation of risk) is a complex, multi-step process, and the results usually have a significant degree of uncertainty because of limitations in data and in the models of environmental and biological systems. In addition, for purposes of generally classifying waste, risk assessment must be generic i.e., it is not intended to apply to disposition of a specific waste in a specific manner at a specific site. 

Radioactive waste disposal—Risk assessment. 2. Hazardous wastes— Risk assessment. 3. Hazardous wastes—Classification. I. National Council on Radiation Protection and Measurements. II. Series. 

Turnberg WL (1996) Biohazardous waste risk assessment, policy, and management. Wiley. 0-471-59421-0... 

PRINCIPLES, DEFINITIONS, AND PERSPECTIVES OF HAZARDOUS WASTE RISK ASSESSMENTS... 

Table 2 Elements of sources, pathways, and receptors algorithm used in hazardous waste risk assessments.

Scientists and engineers involved in hazardous waste risk assessment often have an innate appreciation of the risks associated with hazardous wastes. However, the pubhc, especially those who live near a hazardous waste site or facility, require information regarding the risk assessment process, its uncertainties, and the value judgments that have been made. This information is conveyed through risk communication, an integral part of the risk assessment process. 

The various links of lead and human health with the growing area of risk assessment methodologies are limited by the fact that risk assessment efforts for lead exposure and poisoning risk have been described rather piecemeal in the recent literature. Much of the information covers such areas as extractive industry wastes in the U.S. Inter-Mountain West and industrial or process waste risk assessments across America. 

Many companies use worker—management teams, suggestion boxes, consultant surveys, suppHer training sessions, and other methods to reduce risk of injuries (see Hazard analysis and risk assessment). The principal regulatory burden falls on wastes and discharges which leave the plant (3,53,54). 

It has been traditional to subject workers to higher risks than the public, (a) Write a short discussion of the equities of this practice with consideration for the fact the worker may leave employment that imposed a long term risk, (b) The Nevada Test Site has been selected as a possible location for a high level waste repository. For purposes of the risk assessment, the workers in the repository will be treated as workers with subsequent higher allowable risk. There are many other workers at NTS. Discuss whether these should be treated as workers or public, (c) If they are treated... 

Using formalized risk assessment techniques for industrial ventilation projects may complicate the issue more than necessary. The work environment and its exposure conditions are the focus. However, when evaluating new technology, including waste management, the risk assessment approach may be valuable. 

T. Main, Inc., Healtli Risk Assessment for Air Emission of Metals and Organic Components for tlie Perc Municipal Waste Energy Facilities , PERC, Boston, MA, 1985. 

PBPK models improve the pharmacokinetic extrapolations used in risk assessments that identify the maximal (i.e., the safe) levels for human exposure to chemical substances (Andersen and Krishnan 1994). PBPK models provide a scientifically sound means to predict the target tissue dose of chemicals in humans who are exposed to environmental levels (for example, levels that might occur at hazardous waste sites) based on the results of studies where doses were higher or were administered in different species. Figure 3-4 shows a conceptualized representation of a PBPK model. 

EPA. 1986h. Research and development Reference values for risk assessment. Prepared for the Office of Solid Waste by Environmental Criteria and Assessment Office. Einal draft. Cincinnati, OH U.S. Environmental Protection Agency, Office of Solid Waste. ECAO-CIN-177. 

ENVIRONMENTAL SAMPLING FOR HAZARDOUS WASTES Table I. The Process of Environmental Risk Assessment... 

Another problem of EGAs is that they are non-site-specific. The reasons for this lie in the fact that they include the whole life cycle of systems with resources which may originate in different countries and waste products and emissions which may distribute globally. They deal with factual inputs, outputs and the environmental impact potentials of the system under investigation on a global, and, in some cases, regional scale. Yet, they do not address the intrinsic risks resulting from the system itself. However, a combination with risk assessment methods can be used to close this gap. 

Although none of the three laws or their implementing regulations directly addressed the reuse of waste materials, they necessitate a series of evaluations in the reuse program of solid waste, which include the preparation of an environmental assessment, a human health risk assessment, or an ecosystem risk assessment. 

U.S. EPA may list a waste as hazardous for any and all of the above reasons. The majority of listed wastes fall into the toxic waste category. To decide if a waste should be a toxic listed waste, U.S. EPA first determines whether it typically contains harmful chemical constituents. An appendix to RCRA contains a list of chemical compounds or elements that scientific studies have shown to have toxic, carcinogenic, mutagenic, or teratogenic effects on humans or other life forms. If a waste contains chemical constituents found on the appendix list, U.S. EPA then evaluates 11 other factors to determine if the wastestream is likely to pose a threat in the absence of special restrictions on its handling. These additional considerations include a risk assessment and study of past cases of damage caused by the waste. 

On July 18, 2000, the Agency released HWIR-waste exemption levels for 36 chemicals that were developed using a risk model known as the Multimedia, Multi-pathway and Multi-receptor Risk Assessment (3MRA) Model.17 The May 16, 2001, HWIR-waste rule revised and retained the hazardous waste mixture and derived-from rules as previously discussed in this module. In addition, the rule finalized provisions that conditionally exempt mixed waste (waste that is both radioactive and hazardous), if the mixed waste meets certain conditions in the rule.5... 

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 risk assessment has also concluded that a level of 200 mg/kg for lead in the soil will be a protective level for expected site exposures along with an excess cancer risk level for TCE-contaminated soil (56 pg/L). Based on investigations of activities at the site, the TCE-contaminated soil has not been determined to be a listed RCRA hazardous waste, as the cleaning solution records indicate the solution contained less than 10% TCE. However, the lead-contaminated soil is an RCRA hazardous waste by characteristic in this instance due to extraction procedure (EP) toxicity. None of the waste is believed to have been disposed at the site after November 19, 1980 (the effective date for most of the RCRA treatment, storage, and disposal requirements). 

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... 

K. R. Peterson and T. F. Harvey, "Meteorology and Demography Models for Risk Assessments of Accidental Atmospheric Releases of Nuclear Waste Phase 2 Methodology," Lawrence Livermore Laboratory, Berkeley, California, 1980. 

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