Dermal (percutaneous skin) absorption is a global term that describes the transport of chemicals from the outer surface of the skin both into the skin and into the systemic circulation. Dermal absorption can occur from occupational environmental or consumer skin exposure to chemicals cosmetics and pharmaceutical products. This new volume in the Environmental Health Criteria Series presents an overview of dermal absorption and its consideration in the risk assessment of chemicals. It describes the methods available to assess dermal absorption the significance of skin as a route of exposure and the interpretation of results of dermal absorption studies for risk assessment. In addition it presents and discusses current topics of interest in the field of dermal absorption. This book will be useful to biology and toxicology scientists and researchers as well as to regulatory authorities and the chemical industry.

This new volume in the Environmental Health Criteria series provides a framework for the evaluation of the role of chemical risk factors in the development of autoimmune diseases. In addition to a general introduction to autoimmune mechanisms and clinical expression of autoimmune diseases, a discussion of mechanisms of chemical-associated autoimmune responses precedes information on a range of chemical and other agents. Animal models and human testing for autoimmune disease and the application of information in risk assessment are presented. This book will be useful to biology and toxicology scientists and researchers, as well as to regulatory authorities, industry, and the general risk assessment community.

The purpose of this book is to assess, evaluate, and give guidance on the role of elemental speciation and speciation analysis in human health hazard and risk assessment. The book is directed at risk assessors and regulators, to emphasize the importance of consideration of speciation in their deliberations. To date, this issue has not been a part of most hazard and risk assessments. Further aims of the publication are to encourage the analysis of speciation of elements to increase knowledge on the effect of speciation on mode of action and to increase understanding of health effects.

This book examines the health effects of exposure to static electric and magnetic fields found in selected industries, such as medical facilities with magnetic resonance imaging (MRI), high-energy physics research facilities and some transportation systems. To date, research on their health effects lags far behind the rapid advances in technology. Electric and magnetic fields are generated by natural phenomena such as the Earth s magnetic field, thunderstorms, and by man-made sources that use electricity. When such fields do not vary with time they are referred to as static. For static electric fields, studies carried out to date suggest that the main effect is discomfort from electric discharges to the body. For static magnetic fields, acute effects are only likely to occur when there is movement of a person in the field. For example, a person moving within a relatively high field can experience sensations of vertigo and nausea, and sometimes a metallic taste in the mouth and perceptions of light flashes. Although only temporary, such effects may have a safety impact for workers executing delicate procedures, e.g. surgeons performing operations within MRI units. Even when at rest, a person will experience internal body movement, such as blood flow or heart beat. When placed within a high magnetic field, electrical fields and currents are generated around the heart and major blood vessels that can impede the flow of blood. Possible effects range from minor changes in heartbeat to an increase in the risk of abnormal heart rhythms that might be life threatening."

Scientific knowledge in recent years has demonstrated that children are a vulnerable population subgroup with special susceptibilities and unique exposures to environmental factors that have important implications for public health practices and risk assessment approaches. The heightened susceptibility of children derives primarily from the unique biological and physiological features that characterize the various stages of development from conception through adolescence as well as from certain behavioral characteristics and external factors that may result in increased exposure levels. This new volume in the Environmental Health Criteria (EHC) Series provides a systematic analysis of the scientific principles to be considered in assessing health risks in children; taking into account their unique susceptibilities. The terms children and child as used in this report include the stages of development from conception through adolescence. This new EHC builds on previous volumes addressing methodologies for assessing risks in children: EHC 30 Principles for Evaluating Health Risks to Progeny Associated with Exposure to Chemicals During Pregnancy (WHO 1984) and EHC 59 Principles for Evaluating Health Risks from Chemicals During Infancy and Early Childhood: The Need for a Special Approach (WHO 1986). The central focus of this volume is on the child (developing embryo fetus infant etc.) rather than on a specific environmental agent target organ or disease. Thus it addresses the difficult task of integrating all what is known about both exposure information toxicity data and health outcome at different life stages, which is especially challenging when data are limited for particular life stages (e.g. during pregnancy). The book will be useful to public health officials research and regulatory scientists and risk assessors."

The aim of this publication is to introduce newcomers in this field to transgenic mutagenicity assays and to assess the possible role of these assays in toxicology testing and mechanistic research. Part I gives a short overview of in vivo genotoxicity testing. Part II gives an overview of the data produced by various assays. Part III discusses the use of the assays in research. Part IV evaluates the role and potential added value of transgenic mutation assays in toxicology and risk assessment. The book is directed at toxicologists, research scientists, and risk assessors.

This book examines the health effects of exposure to bentonite, kaolin, and selected clay minerals. Despite the ubiquitous exposure of the general population to low concentrations of montmorillonite and kaolinite, the main components of bentonite and kaolin, respectively, and other clay minerals, no data are available on its effects. Long-term occupational exposure to bentonite dust may cause structural and functional damage to the lungs, but currently available data do not conclusively establish a dose-response or even a cause-and-effect relationship..Long-term exposure to kaolin causes radiologically diagnosed pneumoconiosis but clear-cut deterioration of respiratory function and related symptoms occur only in cases with prominent radiological findings. In this respect, the composition of the non-kaolinite constituents of the clay is important. Bentonite, kaolin, and other clays often contain quartz, exposure to which is causally related to silicosis and lung cancer as well as to statistically significant increases in the incidence of or mortality from chronic bronchitis and pulmonary emphysema. The extensive use of bentonite or kaolin in cosmetics has not been found to produce local or systemic adverse effects. Tests have also revealed that bentonite and kaolin have low toxicity to a wide variety of aquatic species. The biological effects of clay minerals result not only from their composition but also their particle size. In this respect, the decreasing rank order of quartz, kaolinite, and montmorillonite to damage lung tissue is consistent with their known relative active surface areas and surface chemistries.

Zinc is a common element in the natural environment. Apart from artificially reduced zinc metal, it exists in the divalent state Zn (II) in the environment and it is an essential element for most organisms. It is well known that zinc deficiency causes numerous effects in humans, including neurosensory changes, growth retardation and delayed wound healing, but most people obtain sufficient amounts of zinc from their diet to avoid these effects. On the other hand, it is reported that high doses of zinc cause gastrointestinal distress, nausea and diarrhoea.This book evaluates the risks to human health and the environment posed by exposures to zinc. Overall evaluation suggests that normal healthy individuals not exposed to zinc in the workplace are at potentially greater risk from the adverse effects associated with zinc deficiency than from those associated with normal environmental exposure to zinc because of its relatively low toxicity in humans and the limited sources of human exposure.

This publication summarizes the scientific knowledge base on which principles and methods involved in neurotoxicity risk assessment are based. It is aimed at providing a framework for public health officials, research and regulatory scientists and risk managers on the use and interpretation of neurotoxicity data from human and animal studies and it discusses emerging methodological approaches to studying neurotoxicity. The introductory chapter examines definitions and critical concepts in neurotoxicity and looks at the criteria for quality of data used in risk assessment. This is followed by a detailed discussion of the structure and function of the nervous system, of the special susceptibilities of the human fetus, children and the elderly and of the types of effects on the nervous system. Recent progress in developing validated methods for detecting neurotoxicity in humans is investigated, as is our understanding of the factors that affect the validity and reliability of human neurotoxicological studies. Sources of human data include accidental and occupational exposures, case-studies, clinical evaluations, epidemiological studies, and field and laboratory studies. Standardized neuropsychological tests, validated computer-assisted test batteries, neurophysiological and biochemical tests, and refined imaging techniques have been improved and become well established. The most extensive section reviews data derived from experimental animal models. Batteries of functional tests have been developed, validated and used extensively in neurotoxicological studies. Many different types of behavioural tests have been used to assess chemical-induced changes in sensory, motor and cognitive function, whereas neurophysiological measures have been standardized to assess chemical-induced sensory and motor function. The final chapter examines the steps involved in neurotoxicity risk assessment: hazard identification, dose-response assessment, exposure assessment and risk characterization. The application of risk assessment principles for neurotoxicants is similar to that of other non-cancer end-points, except that issues of reversibility, compensation and recovery of function in the nervous system require special consideration. This document provides guidance on neurotoxicity risk assessment at a broad international level.

This book evaluates the risks to human health and the environment posed by arsenic and arsenic compounds. Arsenic is widely distributed in the earth's crust and is emitted into the atmosphere by coal-fired power generation plants and volcanic activity. Inorganic arsenic of geological origin is found in groundwater, which is used as drinking-water in several parts of the world, e.g. Bangladesh. In these areas, drinking-water is the main source of arsenic intake, but elsewhere food is the principal source.

Evaluates the risks to human health and the environment posed by exposure to dinitro-"ortho"-cresol, a chemical used for over a century as an acaricide, larvicide, and ovicide to control the dormant forms of many insects in orchards. The chemical is also sprayed on potatoes to prevent virus and disease contamination of the tubers. Although the chemical's use as a pesticide has been banned in many countries, significant volumes of obsolete stocks are still found in several parts of the world, especially in developing countries. Dinitro-"ortho"-cresol continues to be used in the plastics industry as an inhibitor of polymerization in styrene and vinyl aromatic compounds. Concerning environmental behavior studies indicate that the chemical is rapidly biodegraded in soil and has no potential to volatilize when released to water. Evidence further suggests that uptake by treated fruit trees or potatoes leaving residues at harvest time does not occur. Food is therefore not considered an important source of exposure for the general population. Occupational exposures during agricultural spraying and during manufacturing and formulation are regarded as the principal sources of human exposure. The most extensive part evaluates the results of toxicity studies in laboratory mammals and "in vitro "test systems. Short-term dietary administration decreased body-weight gain in some species, usually without significant alteration in food consumption. At high doses, adverse effects on the liver have been observed. Data on embryotoxicity, teratogenicity, mutagenicity, and carcinogenicity were judged inadequate for evaluation. The evaluation of effects on human health draws on data obtained during the limited use of dinitro-"ortho"-cresol in the 1930s as a therapeutic agent for the treatment of obesity and on cases of acute poisoning. Symptoms associated with toxicity include restlessness, flushed skin, sweating, thirst, deep and rapid respiration, severe increase of body temperature, and cyanosis leading to collapse, coma, and death. Concerning adverse effects on occupationally exposed workers, the report cites a dramatic decline over the last 25 years in reported cases of occupational intoxication. The decline is attributed to better education of users, the use of adequate protective equipment, and improvements in application techniques, equipment, and formulations. The report concludes that when used according to registered recommendations, and when measures for personal protection are followed, exposure to dinitro-"ortho"-cresol is reduced to levels that do not cause systemic toxicity.