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| NIRE Annual Report | 
| 1998 |
Risk Management and Advanced Barrier System for Hazardous Chemicals in Waste LandfillsChemical Substances Risk Assessment DivisionSafety Engineering Department |
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Objectives
Recently, risk management for chemical substances in waste landfills has become extremely important to improve the subsurface environment and groundwater quality. Analytical and technical approaches in order to develop the risk management system for the waste disposal have been conducted. The methodology of exposure assessment for hazardous chemicals in multimedia environment and key technologies for risk management are investigated, and they would be applied to the practical site problems.
Results
Fig.1 shows a conceptual exposure route in subsurface environment for typical industrial chemicals, such as TCE and PCE. They are emitted, migrate and transport in multimedia environment, and might be exposed to organisms. Especially, some specific routes through soil (porous) media and groundwater in waste landfills are important in assessing the risk of VOCs and PCBs. According to the result of exposure assessment, useful and acceptable technologies are selected for risk reduction. Risk assessment of chemicals using the exposure model for specific sites should be corresponded to relevant technical measures for risk reduction. Some of key technologies for risk reduction are summarized as follows;
- Groundwater control in large scale hydrologic system by the site characterization.
- Removal of hazardous chemicals in soil using electrochemical method.
- Improvement of landfill structure using soil compaction method.
- Advanced monitoring method for structure and contaminant transport in sites.
In the process of exposure assessment and the resulting risk characterization, the risk management system would be adopted to the practical site problems.
Selected Publications
1) Risk Management of Hazardous Chemicals in Waste Landfills, J. Jap. Groundwater and Hydrology, 40(2), 1998. 2) Simulation of Contaminant Migration and Transport in Subsurface Environment, J. Safety Eng., 36(6),1997.