Biological markers (biomarkers) are useful tools for understanding the nature and extent of human exposure and risk from environmental toxicants. Biomarkers are classified into three basic categories: exposure, effect, or susceptibility. A marker of exposure is the product of the interaction between a target cell or molecule and a foreign substance (NAS, 1989). These markers can be used to determine the biologically effective dose necessary to elicit a particular physiological change in an organism. A marker of effect is a biochemical or physiological change in an organism that can predict the onset of adverse health effects resulting from a given exposure. Lastly, markers of susceptibility act as indicators of an inherent or acquired tendency of an organism to experience an adverse health effect (NAS, 1989). These markers are already used to detect a variety of diseases and show great promise for developing a better understanding of the mechanicisms of disease. Additionally, biomarkers can be used to establish a more rational basis for quantitative risk extrapolation between species, as weIl as to obtain more precise estimates of the time of critical exposure. These markers can also prove helpful in identifying potentially damaging exposures before the onset of adverse health effects. Biomarkers serve as a valuable exposure assessment tool because they take into account exposure from all routes and integrate exposure from all sources. They have the potential to yield better risk estimates than current monitoring and modeling protocols. In lune 1992, Dr. Travis and Dr.

Evaluation of Flat versus Complex Terrain Models in Estimating Pollutant Transport and Deposition in Complex Terrain; M.W. Yambert, et al. Small Particle Deposition in Air Quality Modeling; R. Kapahi. Accounting for Wet Deposition in Incinerator Risk Assessments; A.A. Campbell, et al. Accounting for Dry Deposition in Incinerator Risk Assessments; C.C. Travis, et al. Gas-Particle Distribution and Atmospheric Deposition of Semivolatile Organic COmpounds; T.F. Bidleman. An Overview of Food Chain Impacts from Municipal Waste Combustion; H.A. Hattemer-Frey, et al. Current Studies on Human Exposure to Chemicals with Emphasis on the Plant Route; S. Paterson, et al. Airto-Leaf Transfer of Organic Vapors to Plants; E. Bacci, et al. Uptake of Organic Contaminants by Plants; C. Mc Farlane. Uncertainties in Estimating Chemical Degradation and Accumulation in the Environment; S.T. Washburn, et al. The Food Chain as a Source of Human Exposure from Municipal Waste Combustion: An Uncertainty Analysis; G. Belcher, et al. Assessing Multiple Pathway Exposures: Variability, Uncertainty, and Ignorance; T.E. McKone. Uncertainty Analysis: An Essential Component of Risk Assessment and Risk Management; R. Tyler, et al. 3 additional articles. Index.

Biological markers (biomarkers) are useful tools for understanding the nature and extent of human exposure and risk from environmental toxicants. Biomarkers are classified into three basic categories: exposure, effect, or susceptibility. A marker of exposure is the product of the interaction between a target cell or molecule and a foreign substance (NAS, 1989). These markers can be used to determine the biologically effective dose necessary to elicit a particular physiological change in an organism. A marker of effect is a biochemical or physiological change in an organism that can predict the onset of adverse health effects resulting from a given exposure. Lastly, markers of susceptibility act as indicators of an inherent or acquired tendency of an organism to experience an adverse health effect (NAS, 1989). These markers are already used to detect a variety of diseases and show great promise for developing a better understanding of the mechanicisms of disease. Additionally, biomarkers can be used to establish a more rational basis for quantitative risk extrapolation between species, as weIl as to obtain more precise estimates of the time of critical exposure. These markers can also prove helpful in identifying potentially damaging exposures before the onset of adverse health effects. Biomarkers serve as a valuable exposure assessment tool because they take into account exposure from all routes and integrate exposure from all sources. They have the potential to yield better risk estimates than current monitoring and modeling protocols. In lune 1992, Dr. Travis and Dr.

Cybernetics, a science concerned with understanding how systems are regulated, has reflected the preoccupations of the century in which it was born. Regulation is important in twentieth century society, where both machines and social organizations are complex. Cybernetics focused on and became primarily associated with the homeostasis or stability of system behavior and with the negative feedbacks that stabilize systems. It paid less attention to the processes opposite to negative feedback, the positive feedback processes that act to change systems. We attempt to redress the balance here by illustrating the enormous importance of positive feedbacks in natural systems. In an article in the American Scientist in 1963, Maruyama called for increased attention to this topic, noting that processes of change could occur when a "deviation in anyone component of the system caused deviations in other components that acted back on the first component to reinforce of amplify the initial deviation." The deviation amplification is the result of positive feedback among system components. Maruyama demonstrated by numerous examples that the neglect of such processes was unjustified and suggested that a new branch of cybernetics, "the second cybernetics," be devoted to their study.

This much-needed book provides an enlightening perspective on the environmental and human health impacts of municipal solid waste (MSW) incineration. Over 100 tables and figures allows speedy access to important data you will refer to again and again. The comprehensive text assesses the human health risks associated with exposure to facility emitted pollutants-especially the highly toxic dioxin. It includes an evaluation of multipathway (inhalation and food chain) exposures. This essential publication also evaluates facility emissions, plausible air concentrations, the potential for deposition of pollutants onto plant, soil, and water surfaces, the movement and accumulation of pollutants through environmental media, and the potential for human exposure. Health Effects of Municipal Waste Incineration is an up-to-date volume which encourages readers to formulate opinions about some of the fundamental issues affecting the management of municipal solid waste. Anyone involved with environmental science, hazardous waste, toxicology, risk analysis and/or environmental engineering will certainly value and utilize this well-written resource.