Phthalates And Cumulative Risk Assessment

People are exposed to a variety of chemicals throughout their daily lives. To protect public health, regulators use risk assessments to examine the effects of chemical exposures. This book provides guidance for assessing the risk of phthalates, chemicals found in many consumer products that have been shown to affect the development of the male reproductive system of laboratory animals. Because people are exposed to multiple phthalates and other chemicals that affect male reproductive development, a cumulative risk assessment should be conducted that evaluates the combined effects of exposure to all these chemicals. The book suggests an approach for cumulative risk assessment that can serve as a model for evaluating the health risks of other types of chemicals.

People are exposed to a variety of chemicals throughout their daily lives. To protect public health, regulators use risk assessments to examine the effects of chemical exposures. This book provides guidance for assessing the risk of phthalates, chemicals found in many consumer products that have been shown to affect the development of the male reproductive system of laboratory animals. Because people are exposed to multiple phthalates and other chemicals that affect male reproductive development, a cumulative risk assessment should be conducted that evaluates the combined effects of exposure to all these chemicals. The book suggests an approach for cumulative risk assessment that can serve as a model for evaluating the health risks of other types of chemicals.

Risk assessment has become a dominant public policy tool for making choices, based on limited resources, to protect public health and the environment. It has been instrumental to the mission of the U.S. Environmental Protection Agency (EPA) as well as other federal agencies in evaluating public health concerns, informing regulatory and technological decisions, prioritizing research needs and funding, and in developing approaches for cost-benefit analysis. However, risk assessment is at a crossroads. Despite advances in the field, risk assessment faces a number of significant challenges including lengthy delays in making complex decisions; lack of data leading to significant uncertainty in risk assessments; and many chemicals in the marketplace that have not been evaluated and emerging agents requiring assessment. Science and Decisions makes practical scientific and technical recommendations to address these challenges. This book is a complement to the widely used 1983 National Academies book, Risk Assessment in the Federal Government (also known as the Red Book). The earlier book established a framework for the concepts and conduct of risk assessment that has been adopted by numerous expert committees, regulatory agencies, and public health institutions. The new book embeds these concepts within a broader framework for risk-based decision-making. Together, these are essential references for those working in the regulatory and public health fields.

In this book, both basic and advanced concepts are discussed for considering mixtures from initial exposure characterization through evaluation of risk associated with combined exposures. This book will provide an introduction to key issues and multiple options for evaluating both the toxicity of mixtures as well as the risk associated with exposure to mixtures. Additionally, promising tools adapted from other disciplines will be discussed in the context of mixtures toxicology and risk assessment. Finally, the discussion will move beyond chemical mixtures to address incorporating non-chemical stressors into toxicity studies and cumulative risk assessments. Although exposure to multiple chemical and non-chemical stressors is the rule, not the exception, consideration of mixtures in toxicology and risk assessment continues to be a significant challenge. This book will be an essential resource for researchers and professionals in the fields of toxicology, epidemiology, exposure science, risk assessment, and statistics.

In the 1970s, flame retardants began to be added to synthetic materials to meet strict flammability standards. Over the years, diverse flame retardants have been manufactured and used in various products. Some flame retardants have migrated out of the products, and this has led to widespread human exposure and environmental contamination. There also is mounting evidence that many flame retardants are associated with adverse human health effects. As a result, some flame retardants have been banned, restricted, or voluntarily phased out of production and use. This publication develops a scientifically based scoping plan to assess additive, nonpolymeric organohalogen flame retardants as a class for potential chronic health hazards under the Federal Hazardous Substances Act, including cancer, birth defects, and gene mutations.

To safeguard public health, the US Environmental Protection Agency (EPA) must keep abreast of new scientific information and emerging technologies so that it can apply them to regulatory decision-making. For decades the agency has dealt with questions about what animal-testing data to use to make predictions about human health hazards, how to perform dose-response extrapolations, how to identify and protect susceptible subpopulations, and how to address uncertainties. As alternatives to traditional toxicity testing have emerged, the agency has been faced with additional questions about how to incorporate data from such tests into its chemical assessments and whether such tests can replace some traditional testing methods. Endocrine active chemicals (EACs) have raised concerns that traditional toxicity-testing protocols might be inadequate to identify all potential hazards to human health because they have the ability to modulate normal hormone function, and small alterations in hormone concentrations, particularly during sensitive life stages, can have lasting and significant effects. To address concerns about potential human health effects from EACs at low doses, this report develops a strategy to evaluate the evidence for such low-dose effects.

Biomonitoring—a method for measuring amounts of toxic chemicals in human tissues—is a valuable tool for studying potentially harmful environmental chemicals. Biomonitoring data have been used to confirm exposures to chemicals and validate public health policies. For example, population biomonitoring data showing high blood lead concentrations resulted in the U.S. Environmental Protection Agency's (EPA's) regulatory reduction of lead in gasoline; biomonitoring data confirmed a resultant drop in blood lead concentrations. Despite recent advances, the science needed to understand the implications of the biomonitoring data for human health is still in its nascent stages. Use of the data also raises communication and ethical challenges. In response to a congressional request, EPA asked the National Research Council to address those challenges in an independent study. Human Biomonitoring for Environmental Chemicals provides a framework for improving the use of biomonitoring data including developing and using biomarkers (measures of exposure), research to improve the interpretation of data, ways to communicate findings to the public, and a review of ethical issues.

This volume of the IARC Monographs provides an assessment of the carcinogenicity of 18 chemicals present in industrial and consumer products or food (natural constituents, contaminants, or flavorings) or occurring as water-chlorination by-products. The compounds evaluated include the widely used plasticizer di(2-ethylhexyl) phthalate and the food contaminant 4-methylimidazole. In view of the limited agent-specific information available from epidemiological studies, the IARC Monographs Working Group relied mainly on carcinogenicity bioassays, and mechanistic and other relevant data to evaluate the carcinogenic hazards to humans exposed to these agents.