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The use of probabilistic risk assessments to establish a range of possible clean-up levels can be used as an effective management tool to predict clean-up costs and select remedial alternatives. A method is described which requires knowledge of the site conditions, a general understanding of remedial options under consideration and estimates of unit costs for clean-up. Examples are provided to show how the method can be and has been applied to waste sites contaminated with carcinogenic heavy metals and benzo(a)pyrene. The mathematical procedure used was: information from a graph of concentration versus risk level was carried forward to determine the quantity of contaminated media at these levels, then unit cost data were used to predict the overall cost., The use of probabilistic risk assessments to establish a range of possible clean-up levels can be used as an effective management tool to predict clean-up costs and select remedial alternatives. A method is described which requires knowledge of the site conditions, a general understanding of remedial options under consideration and estimates of unit costs for clean-up. Examples are provided to show how the method can be and has been applied to waste sites contaminated with carcinogenic heavy metals and benzo(a)pyrene. The mathematical procedure used was: information from a graph of concentration versus risk level was carried forward to determine the quantity of contaminated media at these levels, then unit cost data were used to predict the overall cost.

A methodology for developing and utilising risk-based action levels for soils in site closures is discussed. The methodology is based on standard exposure pathway models which are consistent with current regulatory guidance on conducting risk assessment. A simple approach for evaluating the potential for contamination of ground water from the project criteria based on the Toxicity Characteristic Leachate Procedure (TCLP) is also presented., A methodology for developing and utilising risk-based action levels for soils in site closures is discussed. The methodology is based on standard exposure pathway models which are consistent with current regulatory guidance on conducting risk assessment. A simple approach for evaluating the potential for contamination of ground water from the project criteria based on the Toxicity Characteristic Leachate Procedure (TCLP) is also presented.

A procedure is presented for ranking hazardous waste sites for remedial decisions and an example with application to mining waste sites is discussed. Typical contaminant concentrations are calculated from field data. Exposure indices that compare these measured concentrations with allowable limits are then computed. The limits are selected to protect both the health of humans and the health of key organisms in the ecological food web. The additional exposure index for a site, defined as the sum of all contaminant-specific exposure indices, is then used in ranking the sites and assigning each a priority for remedial action. One key source of uncertainty in the process is the estimation of a typical site concentration from data that include values reported as "below certified reporting limit" (BCRL). This uncertainty is compounded in the additive exposure index and, therefore, may have a substantial effect on the assignment of remediation priority. A general approach is presented for incorporating consideration of BCRL data into uncertainty evaluation when assigning remediation priority designators to hazardous waste sites., A procedure is presented for ranking hazardous waste sites for remedial decisions and an example with application to mining waste sites is discussed. Typical contaminant concentrations are calculated from field data. Exposure indices that compare these measured concentrations with allowable limits are then computed. The limits are selected to protect both the health of humans and the health of key organisms in the ecological food web. The additional exposure index for a site, defined as the sum of all contaminant-specific exposure indices, is then used in ranking the sites and assigning each a priority for remedial action. One key source of uncertainty in the process is the estimation of a typical site concentration from data that include values reported as "below certified reporting limit" (BCRL). This uncertainty is compounded in the additive exposure index and, therefore, may have a substantial effect on the assignment of remediation priority. A general approach is presented for incorporating consideration of BCRL data into uncertainty evaluation when assigning remediation priority designators to hazardous waste sites.

Recent regulatory and policy initiatives under the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) will have a significant effect on risk reduction requirements for the mining and minerals processing industry. The performance of risk analyses and environmental planning of US mining projects is often driven by Federal and state regulatory standards. Regulatory programmes implemented under Federal law including the Safe Drinking Water Act, Clean Water Act and Clean Air Act will also have impacts on industry practices. A brief overview of mining waste and mining waste management is presented. A description of the regulatory initiatives and a discussion on the impacts of new requirements on environmental and risk reduction programs in the mining industry are presented., Recent regulatory and policy initiatives under the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) will have a significant effect on risk reduction requirements for the mining and minerals processing industry. The performance of risk analyses and environmental planning of US mining projects is often driven by Federal and state regulatory standards. Regulatory programmes implemented under Federal law including the Safe Drinking Water Act, Clean Water Act and Clean Air Act will also have impacts on industry practices. A brief overview of mining waste and mining waste management is presented. A description of the regulatory initiatives and a discussion on the impacts of new requirements on environmental and risk reduction programs in the mining industry are presented.

Risk assessment, risk management and engineering/economic feasibility analysis are presented as three effective, practical tools for decision making in the remediation of contaminated soils. Risk assessment is applied to evaluate the extent, magnitude and sources of contamination and to identify appropriate contaminants of concern (COCs). Risk management is then applied to identify the acceptable contaminant residual levels for the COCs. Finally, engineering/economic feasibility analysis is used to define the appropriate cost-effective remedial action levels that will achieve the acceptable contaminant residual levels. A real site application of this decision making approach is presented. This site illustrates that through appropriate engineering, acceptable risk-based contaminant residual levels can be achieved with higher action levels., Risk assessment, risk management and engineering/economic feasibility analysis are presented as three effective, practical tools for decision making in the remediation of contaminated soils. Risk assessment is applied to evaluate the extent, magnitude and sources of contamination and to identify appropriate contaminants of concern (COCs). Risk management is then applied to identify the acceptable contaminant residual levels for the COCs. Finally, engineering/economic feasibility analysis is used to define the appropriate cost-effective remedial action levels that will achieve the acceptable contaminant residual levels. A real site application of this decision making approach is presented. This site illustrates that through appropriate engineering, acceptable risk-based contaminant residual levels can be achieved with higher action levels.