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As part of its core mission, the U.S. Environmental Protection Agency (EPA) is tasked with assessing the hazards and risks to human health from exposure to pollutants. While some pollutants are well studied, there are little or no data on the potential health effects for many thousands of chemicals that can make their way into the environment, such as PFAS. EPA still relies on laboratory mammalian studies as the foundation of most human health risk assessments, which are limited by high costs, long timelines, and other concerns. New approach methods (NAMs) in toxicology, for example new in vivo and in vitro strategies and computational systems biology, offer opportunities to inform timely decision-making when no data are available from laboratory mammalian toxicity tests or epidemiological studies. NAMs may also help inform efforts to protect susceptible and vulnerable populations by characterizing subtle health perturbations, better encompassing genetic diversity, and accounting for nonchemical stressors. While the promise and need for NAMs is clear, many barriers to their use remain. This report aims to bridge the gap between the potential of NAMs and their practical application in human health risk assessment. Building Confidence in New Evidence Streams for Human Health Risk Assessment draws lessons learned from laboratory mammalian toxicity tests to help inform approaches for building scientific confidence in NAMs and for incorporating such data into risk assessment and decision-making. Overall, the report recommendations aim to ensure a seamless handoff from the evaluation of NAM-based testing strategies in the laboratory to the incorporation of NAM data into modern, systematic-review-based risk assessments.

Factoring health and related costs into decision making is essential to confronting the nation's health problems and enhancing public well-being. Some policies and programs historically not recognized as relating to health are believed or known to have important health consequences. For example, public health has been linked to an array of policies that determine the quality and location of housing, availability of public transportation, land use and street connectivity, agricultural practices and the availability of various types of food, and development and location of businesses and industry. Improving Health in the United States: The Role of Health Impact Assessment offers guidance to officials in the public and private sectors on conducting HIAs to evaluate public health consequences of proposed decisions—such as those to build a major roadway, plan a city's growth, or develop national agricultural policies—and suggests actions that could minimize adverse health impacts and optimize beneficial ones. Several approaches could be used to incorporate aspects of health into decision making, but HIA holds particular promise because of its applicability to a broad array of programs, consideration of both adverse and beneficial health effects, ability to consider and incorporate various types of evidence, and engagement of communities and stakeholders in a deliberative process. The report notes that HIA should not be assumed to be the best approach to every health policy question but rather should be seen as part of a spectrum of public health and policy-oriented approaches. The report presents a six-step framework for conducting HIA of proposed policies, programs, plans, and projects at federal, state, tribal, and local levels, including within the private sector. In addition, the report identifies several challenges to the successful use of HIA, such as balancing the need to provide timely information with the realities of varying data quality, producing quantitative estimates of health effects, and engaging stakeholders.

In 2007, the National Research Council envisioned a new paradigm in which biologically important perturbations in key toxicity pathways would be evaluated with new methods in molecular biology, bioinformatics, computational toxicology, and a comprehensive array of in vitro tests based primarily on human biology. Although some considered the vision too optimistic with respect to the promise of the new science, no one can deny that a revolution in toxicity testing is under way. New approaches are being developed, and data are being generated. As a result, the U.S. Environmental Protection Agency (EPA) expects a large influx of data that will need to be evaluated. EPA also is faced with tens of thousands of chemicals on which toxicity information is incomplete and emerging chemicals and substances that will need risk assessment and possible regulation. Therefore, the agency asked the National Research Council to convene a symposium to stimulate discussion on the application of the new approaches and data in risk assessment. The symposium was held on May 11-13, 2009, in Washington, DC, and included presentations and discussion sessions on pathway-based approaches for hazard identification, applications of new approaches to mode-of-action analyses, the challenges to and opportunities for risk assessment in the changing paradigm, and future directions.

In response to a request from the U.S. Army, a committee convened by the National Research Council (NRC) conducted the first in a sequence of studies evaluating the combined health effects of low-level exposure to two chemicals Army personnel are likely to be exposed to in firing tank weapons. The Army sought information on whether the two chemicals, hydrogen cyanide and carbon monoxide, result in similar health impacts and should be assessed together when establishing exposure limits. Based on a review of the scientific literature, the report finds that the biochemical health impacts of the chemicals are similar and that the Army's proposed approach to setting exposure limits is appropriate. Because previous research has focused on high exposures, this initial NRC report recommends that futher neurological studies at low concentrations of exposure to the chemicals be conducted.

To determine whether the air quality inside armored-vehicle cabins can meet exposure guidelines under deployment conditions, the Army assessed possible synergistic toxic effects from potentially harmful substances. This book, the final of two reports on the subject from the National Research Council, addresses whether the approach discussed in the technical context section of the Army's proposed guidance is appropriate, or whether an alternative assessment method should be developed. Combined Exposures to Hydrogen Cyanide and Carbon Monoxide in Army Operations provides several conclusions and recommendations, including the use of alternative instrumentation for monitoring gas, conducting experiments on human subjects, and seeking advice from additional groups involved with personnel training and field deployment.

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.

In light of recent evidence on the relationship of ozone to mortality and questions about its implications for benefit analysis, the Environmental Protection Agency asked the National Research Council to establish a committee of experts to evaluate independently the contributions of recent epidemiologic studies to understanding the size of the ozone-mortality effect in the context of benefit analysis. The committee was also asked to assess methods for estimating how much a reduction in short-term exposure to ozone would reduce premature deaths, to assess methods for estimating associated increases in life expectancy, and to assess methods for estimating the monetary value of the reduced risk of premature death and increased life expectancy in the context of health-benefits analysis. Estimating Mortality Risk Reduction and Economic Benefits from Controlling Ozone Air Pollution details the committee's findings and posits several recommendations to address these issues.

The new field of toxicogenomics presents a potentially powerful set of tools to better understand the health effects of exposures to toxicants in the environment. At the request of the National Institute of Environmental Health Sciences, the National Research Council assembled a committee to identify the benefits of toxicogenomics, the challenges to achieving them, and potential approaches to overcoming such challenges. The report concludes that realizing the potential of toxicogenomics to improve public health decisions will require a concerted effort to generate data, make use of existing data, and study data in new ways—an effort requiring funding, interagency coordination, and data management strategies.

The National Research Council closes the landmark series Drinking Water and Health with Volume 9, published in two parts: Part I: DNA Adducts provides an overview of DNA adducts and their effects on human health, explores the techniques currently in use for detecting them, offers an outlook on future toxicity testing, and lists specific recommendations for action. Part II: Mixtures explores the issues surrounding multiple-chemical exposure from drinking water and reviews options for grouping compounds so their toxicity in mixtures can be reliably assessed. The book describes alternative approaches and considers the option of developing a modified'hazard index'for chemical compounds.

Pharmacokinetics, the study of the movement of chemicals within the body, is a vital tool in assessing the risk of exposure to environmental chemicals. This book—a collection of papers authored by experts in academia, industry, and government—reviews the progress of the risk-assessment process and discusses the role of pharmacokinetic principles in evaluating risk. In addition, the authors discuss software packages used to analyze data and to build models simulating biological phenomena. A summary chapter provides a view of trends in pharmacokinetic modeling and notes some prospective fields of study.

Third printing.

The most recent volume in the Drinking Water and Health series contains the results of a two-part study on the toxicity of drinking water contaminants. The first part examines current practices in risk assessment, identifies new noncancerous toxic responses to chemicals found in drinking water, and discusses the use of pharmacokinetic data to estimate the delivered dose and response. The second part of the book provides risk assessments for 14 specific compounds, 9 presented here for the first time.

Chlorination in various forms has been the predominant method of drinking water disinfection in the United States for more than 70 years. The seventh volume of the Drinking Water and Health series addresses current methods of drinking water disinfection and compares standard chlorination techniques with alternative methods. Currently used techniques are discussed in terms of their chemical activity, and their efficacy against waterborne pathogens, including bacteria, cysts, and viruses, is compared. Charts, tables, graphs, and case studies are used to analyze the effectiveness of chlorination, chloramination, and ozonation as disinfectant processes and to compare these methods for their production of toxic by-products. Epidemiological case studies on the toxicological effects of chemical by-products in drinking water are also presented.

By the Safe Drinking Water Committee under the Assembly's later name, Commission on Life Sciences.

The scientific basis, inference assumptions, regulatory uses, and research needs in risk assessment are considered in this two-part volume. The first part, Use of Maximum Tolerated Dose in Animal Bioassays for Carcinogenicity, focuses on whether the maximum tolerated dose should continue to be used in carcinogenesis bioassays. The committee considers several options for modifying current bioassay procedures. The second part, Two-Stage Models of Carcinogenesis, stems from efforts to identify improved means of cancer risk assessment that have resulted in the development of a mathematical dose-response model based on a paradigm for the biologic phenomena thought to be associated with carcinogenesis.

This book describes hazards from radon progeny and other alpha-emitters that humans may inhale or ingest from their environment. In their analysis, the authors summarize in one document clinical and epidemiological evidence, the results of animal studies, research on alpha-particle damage at the cellular level, metabolic pathways for internal alpha-emitters, dosimetry and microdosimetry of radionuclides deposited in specific tissues, and the chemical toxicity of some low-specific-activity alpha-emitters. Techniques for estimating the risks to humans posed by radon and other internally deposited alpha-emitters are offered, along with a discussion of formulas, models, methods, and the level of uncertainty inherent in the risk estimates.

The regulation of potentially hazardous substances has become a controversial issue. This volume evaluates past efforts to develop and use risk assessment guidelines, reviews the experience of regulatory agencies with different administrative arrangements for risk assessment, and evaluates various proposals to modify procedures. The book's conclusions and recommendations can be applied across the entire field of environmental health.

This book reviews a draft report from the federal government that assesses the effects of oxygenated gasoline on public health, air quality, fuel economy, engine performance, and water quality. In addition to evaluating the scientific basis of the report, the book identifies research needed to better understand the impacts of oxygenated fuels. Methyl tertiary-butyl ether (MTBE), which is intended to reduce carbon monoxide pollution during winter, is the most commonly used additive in the federal oxygenated fuels program. MTBE has been implicated in complaints by the public of headaches, coughs, and nausea. Other questions have been raised about reduced fuel economy and engine performance and pollution of ground water due to the use of MTBE in gasoline. The book provides conclusions and recommendations about each major topic addressed in the government's report.

Scientists agree that exposure to toxic agents in the environment can cause neurological and psychiatric illnesses ranging from headaches and depression to syndromes resembling parkinsonism. It can even result in death at high exposure levels. The emergence of subclinical neurotoxicity—the concept that long-term impairments can escape clinical detection—makes the need for risk assessment even more critical. This volume paves the way toward definitive solutions, presenting the current consensus on risk assessment and environmental toxicants and offering specific recommendations. The book covers: The biologic basis of neurotoxicity. Progress in the application of biologic markers. Reviews of a wide range of in vitro and in vivo testing techniques. The use of surveillance and epidemiology to identify neurotoxic hazards that escape premarket screening. Research needs. This volume will be an important resource for policymakers, health specialists, researchers, and students.

Studying animals in the environment may be a realistic and highly beneficial approach to identifying unknown chemical contaminants before they cause human harm. Animals as Sentinels of Environmental Health Hazards presents an overview of animal-monitoring programs, including detailed case studies of how animal health problems—such as the effects of DDT on wild bird populations—have led researchers to the sources of human health hazards. The authors examine the components and characteristics required for an effective animal-monitoring program, and they evaluate numerous existing programs, including in situ research, where an animal is placed in a natural setting for monitoring purposes.