Joseph G. Bolten

A Policy Analysis of Dutch River Dike Improvements: Trading Off Safety, Cost, and Environmental Impacts

This paper describes a four-month study performed for the Dutch Minister of Transport, Public Works, and Water Management that examined the consequences of alternative policies for providing flood protection to the nontidal branches of the Rijn and Maas Rivers in The Netherlands. The paper focuses on estimating the flood damage that would occur under alternative safety standards, estimating the financial costs of alternative dike improvement strategies, and estimating the damage that would be inflicted on the landscape, natural, and cultural values along the rivers under each of these strategies. The primary objective of the study was to identify policies that would provide a high level of safety, would not cost too much, and would preserve as much as possible of the existing landscape, natural, and cultural values along the rivers. Less than six months after the completion of the study, the Dutch Parliament approved a new river dike policy that was based on the studys results.

Estimating the chronic health risk from coal-fired power plant toxic emissions

Abstract A general methodology for performing risk assessment is briefly discussed. This approach provides a framework within which the analyst can use specific environmental transport, exposure, and dose—response models that are appropriate to a particular problem. The framework has been implemented in a computer program that incorporates simplified environmental transport models with the models for calculating exposure rates and chronic health effects. The general framework and computer program are applied to illustrative case studies of coal-fired power plant emissions of arsenic and selenium. The problem of uncertainty in the results is discussed and several potential analysis approaches evaluated. A selected approach to uncertainty analysis is applied to the case studies. General conclusions about the risk assessment process and specific conclusions about the case studies are presented.

Toxic Effluents: A Simplified Procedure for Assessing Human Health Risks

This paper presents a simplified methodology for assessing the chronic health risks caused by discharge of toxic pollutants to surface water bodies. The methodology has been incorporated into a microcomputer program (WTRISK) and includes simplified transport models for atmospheric, overland, and surface water media, as well as procedures for calculating exposure rates through alternative pathways and the consequent chronic health risks. The program can be used to make preliminary calculations of potential risks and to estimate the uncertainties in the results. With this information, the risk analyst can evaluate discharge problems and determine where additional data or more detailed analysis are required. The approach has been applied to a case study where an effluent containing selenium was discharged from an existing coal-fired power plant. The analysis found that incremental exposure rates and health risks are negligible and that the simplified approach can be used to assess the bounds on potential risks.