a comparative assessment of the total environmental impacts of waste incineration as a management option, the above-mentioned considerations should be included.
Despite past efforts to characterize the potential health risks at numerous individual existing and proposed incineration sites, the committee has carried out this study with rather sparse information on the relationship between human exposure to pollutants released to the environment through waste incineration and the occurrence of health effects because such information is generally unknown. One reason, for example, for the lack of information is that few epidemiologic studies have been conducted to investigate exposures to incineration emissions and their human health consequences. Although the committee was not asked to and did not attempt to perform its own epidemiologic studies or risk assessments at individual waste-incineration facilities, the committee used available data on human and animal exposures to specific substances to examine the implications for incinerator sites of dose-response projections (see Chapter 5).
The committee conducted this study with the understanding that society faces the challenge of choosing among various waste-management alternatives. Although a comparative health risk assessment of alternatives for managing waste streams was not part of its charge, the committee conducted this study with the intent of informing the public debate over appropriate uses of waste incineration.
The emission-receptor framework, described earlier, was used to develop and organize the chapters of this report. The six components of the charge to the committee are addressed within these chapters. Chapter 2 presents an overview of waste generation, waste stream composition, and waste-management activities that affect the characteristics of waste fed into incineration facilities. Chapter 3 discusses various incineration processes used to burn waste, characteristics of emissions of certain contaminants, operating practices and design options most likely to affect emissions, and expectations regarding the technology and release of hazardous contaminants from incineration facilities. Chapter 4 discusses the environmental transport and fate of pollutants once they have left an incineration facility, and considers the contribution of incineration to ambient concentrations of such pollutants.
Chapter 5 examines the techniques used to evaluate the potential for health effects from incineration, and discusses some of the results obtained with those techniques. It also relates human health risk estimates to issues discussed in Chapter 3 and Chapter 4 with respect to various design and operating conditions at waste-combustion facilities. In addition, Chapter 5 identifies important considerations for developing health-based performance criteria to demonstrate that a combustion facility meets and maintains agreed-upon health-risk tolerance levels.