Board on Environmental Studies and Toxicology – författare

Assessment of the U.S. Outer Continental Shelf Environmental Studies Program reviews the ecological studies done by the Environmental Studies Program of the Minerals Management Service. This program, which has spent $10 million a year on ecological studies in recent years, is designed to provide information to predict and manage the environmental effects of outer continental shelf oil and gas activities. The book considers studies on marine mammals and endangered species, birds, benthic organisms, fisheries, and marine ecosystems and makes recommendations for future studies.

Recognizing the importance of wetland protection, the Bush administration in 1988 endorsed the goal of a /no net lossa of wetlands. Specifically, it directed that filling of wetlands should be avoided, and minimized when it cannot be avoided. When filling is permitted, compensatory mitigation must be undertaken; that is, wetlands must be restored, created, enhanced, and, in exceptional cases, preserved, to replace the permitted loss of wetland area and function, such as water quality improvement within the watershed. After more than a dozen years, the national commitment to a /no net lossa of wetlands has been evaluated. This new book explores the adequacy of science and technology for replacing wetland function and the effectiveness of the federal program of compensatory mitigation in accomplishing the nationa (TM)s goal of clean water. It examines the regulatory framework for permitting wetland filling and requiring mitigation, compares the mitigation institutions that are in use, and addresses the problems that agencies face in ensuring sustainability of mitigated wetlands over the long term.Gleaning lessons from the mixed results of mitigation efforts to date, the book offers 10 practical guidelines for establishing and monitoring mitigated wetlands. It also recommends that federal, state, and local agencies undertake specific institutional reforms. This book will be important to anyone seeking a comprehensive understanding of the a /no net lossa issue: policy makers, regulators, environmental scientists, educators, and wetland advocates.

The U.S. Environmental Protection Agency's (EPA) Integrated Risk Information System (IRIS) program develops human health assessments that focus on hazard identification and dose-response analyses for chemicals in the environment. The ORD Staff Handbook for Developing IRIS Assessments (the handbook) provides guidance to scientists who perform the IRIS assessments in order to foster consistency in the assessments and enhance transparency about the IRIS assessment process. At the request of the EPA, this report reviews the procedures and considerations for operationalizing the principles of systematic reviews and the methods described in the handbook for determining the scope of the IRIS assessments, evidence integration, extrapolation techniques, dose-response analyses, and characterization of uncertainties.

To protect space crews from contaminants in potable and hygiene water, NASA requested that the National Research Council (NRC) provide guidance on how to develop water exposure guidelines and subsequently review NASAa (TM)s development of exposure guidelines for specific chemicals.

The Water Science and Technology Board and the Board on Environmental Studies and Toxicology have released the seventh and final report of the Committee on Restoration of the Greater Everglades Ecosystem, which provides consensus advice to the South Florida Ecosystem Restoration Task Force on various scientific and technical topics. Human settlements and flood-control structures have significantly reduced the Everglades, which once encompassed over three million acres of slow-moving water enriched by a diverse biota. To remedy the degradation of the Everglades, a comprehensive Everglades Restoration Plan was formulated in 1999 with the goal of restoring the original hydrologic conditions of its remaining natural ecosystem. A major feature of this plan is providing enough storage capacity to meet human needs while also providing the needs of the greater Everglades ecosystem. This report reviews and evaluates not only storage options included in the Restoration Plan but also other options not considered in the Plan.Along with providing hydrologic and ecological analyses of the size, location and functioning of water storage components, the report also discusses and makes recommendations on related critical factors, such as timing of land acquisition, intermediate states of restoration, and tradeoffs among competing goals and ecosystem objectives.

Extremely hazardous substances (EHSs), as defined in the Superfund Amendments and Reauthorization Act of 1986, can be released accidentally as a result of chemical spills, industrial explosions, fires, or accidents involving railroad cars or trucks used in transporting these substances, or intentionally through terrorist activities. It is also feasible that these substance can be released by improper storage and/or handling. Workers and residents in communities surrounding industrial facilities where EHSs are manufactured, used, or stored and in communities along the nationa (TM)s railways and highways are potentially at risk of being exposed to airborne EHSs during accidental and intentional releases. This report provides technical guidance on establishing community Acute Exposure Guideline Levels (AEGLs) for certain hazardous chemicals. It reviews the scientific validity of AEGLs developed by the national Advisory Committee on Acute Exposure Guideline Levels for Hazardous Substances, identifies research priorities, and identifies guidance issues that may require modification or further development based on the toxicological database for the chemicals reviewed.This twelfth interim report offers recommendations for improving AEGLs for the following 15 chemicals: toluene, xylenes, ammonia, bromine, aniline, methyl ethyl ketone, hydrazine, iron pentacarbonyl, phosphine, chlorine, trifluoride, ethyleneimine, propyleneimine, allyl alcohol, ethylene oxide, and nickel carbonyl.

The Clean Air Act established a pair of programsa "known as New Source Review (NSR)a "that regulate large stationary sources of air pollution, such as factories and electricity-generating facilities. Congress then asked the National Research Council to estimate the effects of NSR rule changes made in 2002 and 2003 in terms of the effects on emissions and human health, and changes in operating efficiency (including energy efficiency), pollution prevention, and pollution-control activities. New Source Review for Stationary Sources of Air Pollution provides insights into the potential effects of the rule changes on national emissions from the electric power industry. Although this book focuses on the 2002 and 2003 rules, its analytic framework applies to other possible changes in NSR and to other regulatory contexts. Helpful, in that it outlines the data-collection efforts needed to assess the impact of the NSR rules, the book recommends EPA and other government agencies undertake and sustain the recommended methods.

Beryllium is an important metal that is used in a number of industries-including the defense, aerospace, automotive, medical, and electronics industries-because of its exceptional strength, stability, and heat-absorbing capability. It is found in a variety of technologies, including nuclear devices, satellite systems, missile systems, radar systems, bushings and bearings in aircraft and heavy machinery, x-ray machines used for mammography, cellular telephone components, computer components, and connectors for fiber optics. To help determine the steps necessary to protect its workforce from the adverse effects of exposure to beryllium used in military aerospace applications, the U.S. Air Force requested that the National Research Council's Committee on Toxicology (COT) conduct an independent evaluation of the scientific literature on beryllium, provide risk estimates for cancer and noncancer health end points, and make recommendations about specific tests for surveillance and biomonitoring of workers. The request specified that two reports be produced to accomplish those tasks.The first is to provide a review of the scientific literature on beryllium, and the second will expand more critically on the review in considering the maximum chronic inhalation exposure levels that are unlikely to produce adverse health effects, in estimating carcinogenic risks, and in providing guidance on testing methods for surveillance and monitoring of worker populations and other specific issues detailed in the statement of task. In response to the U.S. Air Force request, COT convened the Committee on Beryllium Alloy Exposures, which prepared this first report. Health Effects of Beryllium Exposure : A Literature Review identifies the available toxicologic, epidemiologic, and other literature on beryllium that is most relevant for addressing the statement of task, focusing primarily on beryllium sensitization, CBD, and cancer.

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.

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.

Advances in molecular biology and toxicology are paving the way for major improvements in the evaluation of the hazards posed by the large number of chemicals found at low levels in the environment. The National Research Council was asked by the U.S. Environmental Protection Agency to review the state of the science and create a far-reaching vision for the future of toxicity testing. The book finds that developing, improving, and validating new laboratory tools based on recent scientific advances could significantly improve our ability to understand the hazards and risks posed by chemicals. This new knowledge would lead to much more informed environmental regulations and dramatically reduce the need for animal testing because the new tests would be based on human cells and cell components. Substantial scientific efforts and resources will be required to leverage these new technologies to realize the vision, but the result will be a more efficient, informative and less costly system for assessing the hazards posed by industrial chemicals and pesticides.

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.

The control of illicit-drug trafficking and drug use is a difficult and complex process that involves a variety of prevention, control, treatment, and law enforcement strategies. Eradication strategies for controlling illicit-drug crops are used to target the beginning of the drug-supply chain by preventing or reducing crop yields. Mycoherbicides have been proposed as an eradication tool to supplement the current methods of herbicide spraying, mechanical removal, and manual destruction of illicit-drug crops. Some people regard them as preferable to chemical herbicides for controlling illicit-drug crops because of their purported specificity to only one plant species or a few closely related species. As living microorganisms, they have the potential to provide long-term control if they can persist in the environment and affect later plantings. Research on mycoherbicides against illicit-drug crops has focused on three pathogens: Fusarium oxysporum f.sp. cannabis for cannabis (Cannabis sativa), F. oxysporum f.sp. erythroxyli for coca (Erythroxylum coca and E. novogranatense), and Crivellia papaveracea or Brachycladium papaveris (formerly known as Pleospora papaveracea and Dendryphion penicillatum, respectively) for opium poppy (Papaver somniferum).Feasibility of Using Mycoherbicides for Controlling Illicit Drug Crops addresses issues about the potential use of the proposed mycoherbicides: their effectiveness in eradicating their target plants; the feasibility of their large-scale industrial manufacture and delivery; their potential spread and persistence in the environment; their pathogenicity and toxicity to nontarget organisms, including other plants, fungi, animals, and humans; their potential for mutation and resulting effects on target plants and nontarget organisms; and research and development needs. On the basis of its review, the report concludes that the available data are insufficient to determine the effectiveness of the specific fungi proposed as mycoherbicides to combat illicit-drug crops or to determine their potential effects on nontarget plants, microorganisms, animals, humans, or the environment. However, the committee offers an assessment of what can and cannot be determined at the present time regarding each of the issues raised in the statement of task.

Lead is a ubiquitous metal in the environment, and its adverse effects on human health are well documented. Lead interacts at multiple cellular sites and can alter protein function in part through binding to amino acid sulfhydryl and carboxyl groups on a wide variety of structural and functional proteins. In addition, lead mimics calcium and other divalent cations, and it induces the increased production of cytotoxic reactive oxygen species. Adverse effects associated with lead exposure can be observed in multiple body systems, including the nervous, cardiovascular, renal, hematologic, immunologic, and reproductive systems. Lead exposure is also known to induce adverse developmental effects in utero and in the developing neonate. Lead poses an occupational health hazard, and the Occupational Safety and Health Administration (OSHA) developed a lead standard for general industry that regulates many workplace exposures to this metal.The standard was promulgated in 1978 and encompasses several approaches for reducing exposure to lead, including the establishment of a permissible exposure limit (PEL) of 50 mug/m3 in air (an 8-hour time-weighted average [TWA]), exposure guidelines for instituting medical surveillance, guidelines for removal from and return to work, and other risk-management strategies. An action level of 30 mug/m3 (an 8-hour TWA) for lead was established to trigger medical surveillance in employees exposed above that level for more than 30 days per year. Another provision is that any employee who has a blood lead level (BLL) of 60 mug/dL or higher or three consecutive BLLs averaging 50 mug/dL or higher must be removed from work involving lead exposure. An employee may resume work associated with lead exposure only after two BLLs are lower than 40 mug/dL. Thus, maintaining BLLs lower than 40 mug/dL was judged by OSHA to protect workers from adverse health effects. The OSHA standard also includes a recommendation that BLLs of workers who are planning a pregnancy be under 30mug/dL.In light of knowledge about the hazards posed by occupational lead exposure, the Department of Defense (DOD) asked the National Research Council to evaluate potential health risks from recurrent lead exposure of firing-range personnel. Specifically, DOD asked the National Research Council to determine whether current exposure standards for lead on DOD firing ranges protect its workers adequately.The committee also considered measures of cumulative lead dose. Potential Health Risks to DOD Firing-Range Personnel from Recurrent Lead Exposure will help to inform decisions about setting new air exposure limits for lead on firing ranges, about whether to implement limits for surface contamination, and about how to design lead-surveillance programs for range personnel appropriately.

Potential health effects from chemicals that disrupt endocrine function pose an environmental health concern because of their ability to interfere with normal hormone function in human and wildlife populations. The endocrine system regulates biological processes throughout the body and is sensitive to small changes in hormone concentrations. Endocrine-disruptor research has focused primarily on chemicals that affect three hormone pathways that play important roles in reproduction and development - the estrogen, androgen, and thyroid hormone pathways. Some of this research has identified dose-response relationships that have nonmonotonic curves. Nonmonotonic dose-response curves (NMDRs) are of concern because they do not follow the usual assumption made in toxicology that as dose decreases the response also decreases. The existence of NMDRs has been a controversial topic for decades, and there has been considerable debate about their implications for how chemicals are tested and for how risks from such chemicals are assessed.Toxicity tests are designed to identify hazards and to characterize dose-response relationships, so tests are aimed at finding a (high) dose that elicits a response, and dose-response is explored by testing lower doses spaced to identify statistically a no- or lowest-observed-adverse-effect level. The concern for NMDRs is that such studies, as currently designed, might not detect the inflection of the dose-response curve if only a few doses are tested or if the change in inflection occurs below the range of doses tested. Another concern is that some NMDRs are found for biological effects that are not usually evaluated in toxicity tests. If current testing strategies are inadequate to account for NMDRs, changes to risk assessment practices might be necessary. To help address these issues, the U.S. Environmental Protection Agency (EPA) developed a draft State-of-the-Science Evaluation: Nonmonotonic Dose Responses as they Apply to Estrogen, Androgen, and Thyroid Pathways and EPA Testing and Assessment Procedures. EPA asked the National Research Council to conduct an independent review of this evaluation to ensure that it is scientifically sound and of high quality.Review of Environmental Protection Agency's State-of-the-Science Evaluation of Nonmonotonic Dose-Response as they Apply to Endocrine Disrupters evaluates whether EPA's evaluation presents a scientifically sound and high-quality analysis of the literature on NMDRs. This report reviews how well the EPA evaluation described how the assessment was performed, whether consistent methods and criteria were applied in the analysis of different evidence streams, and whether appropriate methods were applied to evaluating the evidence. The report makes recommendations to improve EPA's process and strengthen the evaluation.

Many people in the United States are exposed to styrene. Sources of environmental exposure included food (from migration of styrene from polymer packaging materials), cigarette smoke, vehicle exhaust and other forms of combustion and incineration of styrene polymers. Occupational exposure to humans can occur during the industrial processing of styrene. It is used to create a broad spectrum of products, including latex paints and coatings; synthetic rubbers; construction materials, such as pipes, fittings, and lighting fixtures; packaging; household goods, such as synthetic marble, flooring, and molded furnishings; and automotive parts. In 2011, the National Toxicology Program (NTP) listed styrene as "reasonably anticipated to be a human carcinogen" in its 12th Report on Carcinogens, marking the first time that the substance was listed. Congress directed the Department of Health and Human Services to arrange for the National Academy of Sciences to independently review the substance profile of styrene and it listing in the NTP report.Review of the Styrene Assessment in the National Toxicology Program 12th Report on Carcinogens concurs with the NTP determination that there is limited but credible evidence that exposure to styrene in some occupational settings is associated with an increase in the frequency of lymphohematopoietic cancers. Additionally, the NRC report authoring committee independently reviewed the scientific evidence from studies in humans, experimental animals, and other studies relevant to the mechanisms of carcinogenesis and made level-of-evidence conclusions. Based on credible but limited evidence of carcinogenicity in traditional epidemiologic studies, on sufficient evidence of carcinogenicity in animals, and on convincing evidence that styrene is genotoxic in exposed humans, this report finds that compelling evidence exists to support a listing of styrene as, at a minimum, "reasonably anticipated to be a human carcinogen."

In its current strategic plan, the U.S. Environmental Protection Agency (EPA) describes a cross-agency strategy to advance sustainable environmental outcomes and optimize economic and social outcomes through Agency decisions and actions. Sustainability has evolved from an aspiration to a growing body of practices. The evolution includes a transition from the development of broad goals toward the implementation of specific policies and programs for achieving them and the use of indicators and metrics for measuring progress. Without losing focus on implementing its existing regulatory mandates, EPA's incorporation of sustainability considerations into its decision-making about potential environmental, social, and economic outcomes involves shifting from a focus on specific pollutants in an environmental medium (air, water, or land) to a broader assessment of interactions among human, natural, and manufactured systems. EPA has indicated that it will need to consider the use of a variety of analytic tools and approaches to assess the potential sustainability-related effects of its decisions and actions in response to complex environmental challenges.Sustainability Concepts in Decision-Making: Tools and Approaches for the U.S. Environmental Protection Agency examines scientific tools and approaches for incorporating sustainability concepts into assessments used to support EPA decision making. Using specific case studies, this report considers the application of analytic and scientific tools, methods, and approaches presented in the 2011 NRC report Sustainability and the U.S. EPA. This report examines both currently available and emerging tools, methods, and approaches to find those most appropriate for assessing and/or evaluating potential economic, social and environmental outcomes within an EPA decision context. Sustainability Concepts in Decision Making also discusses data needs and post-decision evaluation of outcomes on dimensions of sustainability. A broad array of sustainability tools and approaches are suitable for assessing potential environmental, social, and economic outcomes in EPA's decision-making context. The recommendations of this report will assist the agency to optimize environmental, social, and economic outcomes in EPA decisions.

The Environmental Protection Agency (EPA) applies scientific results that have been provided by various parts of its own organization and by external organizations. The agency requires substantial high-quality inhouse scientific expertise and laboratory capabilities so that it can answer questions related to regulation, enforcement, and environmental effects of specific chemicals, activities, and processes. It is also usually faced with situations in which research or analytic work is time-critical, so it maintains dedicated laboratory staff and facilities that can respond quickly to such needs. In recent years, EPA has made several changes to improve the efficiency and effectiveness of its laboratories, such as the designation of national program directors to align the work of research laboratories with the needs of the agency's regulatory program offices. The agency is currently undertaking an integrated evaluation of it laboratories to enhance the management effectiveness and efficiency of its laboratory enterprise and to enhance its capabilities for research and other laboratory-based scientific and technical activities.The results of EPA's evaluation are expected to include options for colocation and consolidation of laboratory facilities. Rethinking the Components, Coordination, and Management of U.S. Environmental Protection Agency Laboratories assesses EPA's highest-priority needs for mission-relevant laboratory science and technical support, develops principles for the efficient and effective management of EPA's laboratory enterprise to meet the agency's mission needs and strategic goals, and develops guidance for enhancing efficiency and effectiveness now and during the next 10 years. EPA's laboratories play a vital role in the agency's work. The findings and recommendations of this report will help EPA to develop an implementation plan for the laboratory enterprise.

The California Department of Pesticide Regulation(DPR)conducts human health risk assessments as part of its mission to ensure the protection of workers and public health in the state. The risk assessments identify potential health hazards posed by pesticides, characterize dose-response relationships, and estimate exposure to characterize potential risks to humans. Over the last decade, advances in methods of scientific and technical analysis have led to improvements in the risk-assessment process that have made them more rigorous, transparent, and useful to risk managers. In light of the advances, the California legislature asked DPR to arrange an independent peer review of the agency's risk-assessment practices to ensure that they are scientifically and technically credible. Review of California's Risk-Assessment Process for Pesticides examines DPR's processes of hazard identification, exposure assessment, dose-response analysis, and risk characterization to determine whether they are consistent with best practices.This report also evaluates the methods used for setting priorities among pesticides for risk assessment and identifies possible options for improving efficiency and productivity. Recommendations of this report will help to make the process more transparent and defensible.

Human spaceflight is inherently risky, with numerous potential hazards posed at each phase of a mission. Potential health risks during spaceflights include short-term health consequences from being in microgravity, as well as long-term health consequences that arise, or continue, months or years after a flight. Additional health considerations are risks posed by exposure to environmental contaminants onboard spacecraft. Because the International Space Station and spacecraft are closed environments that require recirculation of air and water supplies, some contamination of the air and water will occur. Even with onboard air and water purification systems, chemicals will accumulate in the air and water as they recirculate or are recycled onboard. Therefore, it is necessary for the National Aeronautics and Space Administration (NASA) to identify hazardous contaminants and determine exposure levels that are not expected to pose a health risk to astronauts.NASA uses spacecraft maximum allowance concentrations (SMACs) and spacecraft water exposure guidelines (SWEGs) to provide guidance on acceptable exposures to air and water contaminants during normal operations and emergency situations. Refinements to the Methods for Developing Spacecraft Exposure Guidelines updates the methods for establishing SMACs and SWEGs and assists NASA with identifying chemicals that need updated SMACs or SWEGs and new chemicals for which these guidelines should be developed.

The Superfund program of the US Environmental Protection Agency (EPA) was created in the 1980s to address human-health and environmental risks posed by abandoned or uncontrolled hazardous-waste sites. Identification of Superfund sites and their remediation is an expensive multistep process. As part of this process, EPA attempts to identify parties that are responsible for the contamination and thus financially responsible for remediation. Identification of potentially responsible parties is complicated because Superfund sites can have a long history of use and involve contaminants that can have many sources. Such is often the case for mining sites that involve metal contamination; metals occur naturally in the environment, they can be contaminants in the wastes generated at or released from the sites, and they can be used in consumer products, which can degrade and release the metals back to the environment. This report examines the extent to which various sources contribute to environmental lead contamination at Superfund sites that are near lead-mining areas and focuses on sources that contribute to lead contamination at sites near the Southeast Missouri Lead Mining District. It recommends potential improvements in approaches used for assessing sources of lead contamination at or near Superfund sites.

In thousands of communities across the United States, drinking water is contaminated with chemicals known as perfluoroalkyl and polyfluoroalkyl substances (PFAS). PFAS are used in a wide range of products, such as non-stick cookware, water and stain repellent fabrics, and fire-fighting foam, because they have properties that repel oil and water, reduce friction, and resist temperature changes. PFAS can leak into the environment where they are made, used, disposed of, or spilled. PFAS exposure has been linked to a number of adverse health effects including certain cancers, thyroid dysfunction, changes in cholesterol, and small reductions in birth weight.This report recommends that the Centers for Disease Control and Prevention (CDC) update its clinical guidance to advise clinicians to offer PFAS blood testing to patients who are likely to have a history of elevated exposure, such as those with occupational exposures or those who live in areas known to be contaminated. If testing reveals PFAS levels associated with an increased risk of adverse effects, patients should receive regular screenings and monitoring for these and other health impacts. Guidance on PFAS Exposure, Testing, and Clinical Follow-Up recommends that the CDC, Agency for Toxic Substances and Disease Registry (ATSDR), and public health departments support clinicians by creating educational materials on PFAS exposure, potential health effects, the limitations of testing, and the benefits and harms of testing.

Trichloroethylene (TCE) is a solvent that is used as a degreasing agent, a chemical intermediate in refrigerant manufacture, and a component of spot removers and adhesives. It is produced in mass quantities but creates dangerous vapors and is an environmental contaminant at many industrial and government facilities, including facilities run by the U.S. Department of Defense (DoD). It is important to determine the safe occupational exposure level (OEL) for the solvent in order to protect the health of workers who are exposed to its vapors. However, there are concerns that the current occupational standards insufficiently protect workers from these health threats. Review of DOD's Approach to Deriving an Occupational Exposure Level for Trichloroethylene makes recommendations to improve the DoD's approach to developing an OEL for TCE, strengthen transparency of the process, and improve confidence in the final OEL value. This report reviews the DoD's approach using a literature review, evidence synthesis based on weight of evidence [WOE], point-of-departure derivation, physiologically based pharmacokinetic modeling, extrapolation tools, and explores other elements of the process of deriving an OEL for TCE. It examines scientific approaches to developing exposure values and cancer risk levels, defining the scope of the problem, and improving hazard identification.

Biokinetic modeling provides a mathematical technique for estimating absorption, distribution, metabolism, and excretion of chemicals, including particles and metals, in humans. Such models can be used to relate the amount of lead external exposure to the amount of lead found in the blood and other tissues at different points in time. At the request of the Department of Defense (DoD), Review of the Department of Defense Biokinetic Modeling Approach in Support of Establishing an Airborne Lead Exposure Limit evaluates whether the model used by DoD to derive airborne lead concentrations from blood lead levels is appropriate. This report also considers whether DoD's modifications to the model are appropriately justified, and whether the assumptions in and inputs to the model are reasonable.

Humans are potentially exposed to more than 80,000 toxic chemicals in the environment, yet their impacts on brain health and disease are not well understood. The sheer number of these chemicals has overwhelmed the ability to determine their individual toxicity, much less potential interactive effects. Early life exposures to chemicals can have permanent consequences for neurodevelopment and for neurodegeneration in later life. Toxic effects resulting from chemical exposure can interact with other risk factors such as prenatal stress, and persistence of some chemicals in the brain over time may result in cumulative toxicity. Because neurodevelopmental and neurodegenerative disorders - such as attention-deficit hyperactivity disorder and Parkinson's disease - cannot be fully explained by genetic risk factors alone, understanding the role of individual environmental chemical exposures is critical.On June 25, 2020, the National Academies of Sciences, Engineering, and Medicine's Forum on Neuroscience and Nervous System Disorders hosted a workshop to lay the foundation for future advances in environmental neuroscience. The workshop was designed to explore new opportunities to bridge the gap between what is known about the genetic contribution to brain disorders and what is known, and not known, about the contribution of environmental influences, as well as to discuss what is known about how genetic and environmental factors interact. This publication summarizes the presentation and discussion of the workshop.

Systematic review - a scientific investigation that focuses on a specific question and uses explicit, prespecified scientific methods to identify, select, assess, and summarize the findings of similar but separate studies - has become the foundation for assessing evidence to be used for decision making in a variety of health contexts, including health care and public health.At the request of the Environmental Protection Agency (EPA), this publication reviews EPA's 2018 guidance document Application of Systematic Review in TSCA (Toxic Substances and Control Act) Risk Evaluations and associated materials to determine whether the process is comprehensive, workable, objective, and transparent.

A scientific workforce with cutting-edge skills is critical for the ability of the U.S. Environmental Protection Agency to carry out its mission to protect human health by identifying environmental hazards, evaluating risks to public health and ecosystems, and formulating effective methods for pollution control and prevention. To aid in the selection and hiring of premier scientists and engineers, in 2006, EPA first sought the ability to directly recruit world-renowned scientists and engineers from academia, private industry, and other government agencies under Title 42, Section 209, of the U.S. Code. Title 42 authorizes federal agencies to appoint highly qualified scientists and engineers outside of standard civil service positions. Congress reauthorizes the EPA Title 42 authority in 5-year increments.To guide decisions about the future of the program, Congress asked the National Academies to review past and current EPA use of Title 42 hiring authority and how the program might be improved. The report finds that EPA has used its limited Title 42 authority effectively since 2006 and that Title 42 authority has enabled the hiring of effective scientific leadership and improved the scientific capability and capacity to support the Agency mission. Furthermore, the report finds that Title 42 can help the agency in addressing future environmental complexities. In continuing to enhance its scientific workforce and maintain a position at the forefront of evolving scientific knowledge, EPA would benefit from Congressional approval for permanent Title 42 authority.

Ethylene oxide is primarily produced in Texas and Louisiana with sites in Texas accounting for nearly half of all emitted ethylene oxide in the United States. Because ethylene oxide is emitted in Texas and has been determined by other agencies to be a carcinogen, the Texas Commission on Environmental Quality (TCEQ) undertook a carcinogenic dose-response assessment for use in TCEQ's remediation and air permitting programs. The TCEQ assessed the carcinogenic hazards of ethylene oxide and derived a chronic inhalation unit risk factor (URF) in its 2020 Ethylene Oxide Carcinogenic Dose-Response Assessment Development Support Document (TCEQ DSD).As requested by TCEQ, the National Academies of Sciences, Engineering, and Medicine assembled an ad hoc committee to review the methods, results, and conclusions of the TCEQ DSD. The committee considered whether the conclusions are clearly presented, scientifically supported, and based on the best available scientific information. The report finds that the lack of application of systematic review methods, the exclusion of critical epidemiological data, the limitations in the modeling approach and use of unpublished validation data all contribute to a lack of confidence in TCEQ's risk assessment of ethylene oxide.