Since the first edition in 1948, "Patty's Industrial Hygiene and Toxicology" has become a flagship publication for Wiley. In the course of its nearly six decades in print, it has evolved into a standard reference for the fields of occupational health and toxicology. The volumes on Industrial Hygiene are cornerstone reference works for chemists, engineers, toxicologists, and occupational safety personnel.

Since the 5th edition was published, the field of IH has changed with personnel often working for multinational firms, self-employed, at small consulting firms. Their environment has changed and expanded, and thus also the types of information and resources required have changed. The traditional areas of interest to occupational health and safety professionals include anticipation, recognition, evaluation and control of potential hazards. In addition to these, the 6th edition provides information and reliable resources to prepare for natural disasters, exposures to biological agents and potential acts of terrorism.

Since the first edition in 1948, "Patty's Industrial Hygiene and Toxicology" has become a flagship publication for Wiley. In the course of its nearly six decades in print, it has evolved into a standard reference for the fields of occupational health and toxicology. The volumes on Industrial Hygiene are cornerstone reference works for chemists, engineers, toxicologists, and occupational safety personnel.

Volume 3 covers Recognition and Evaluation of Physical Agents and Recognition of Biohazards. Almost all of the chapters in the section Recognition and Evaluation of Physical Agents are new. Three new chapters are in the section on Biohazards: Bioaerosols, Bloodborne Pathogens, and Tuberculosis and Other Mycobacteria Communicable Diseases. These subjects are increasing in importance to industrial hygienists.

An updated edition of the cornerstone reference work for chemists, engineers, toxicologists, and occupational safety personnel, the new "Sixth Edition" of "Patty's Industrial Hygiene" offers timely coverage on natural disasters, exposures to biological agents, and potential acts of terrorism."Volume 4" covers environmental, health and safety program management, with a number of new chapters on international regulations and laws, hospital health and safety, fire safety (including explosions/reactions), managing industrial hygiene in a multicultural environment, and emergency and disaster response.

"Advances in Molecular Toxicology" features the latest advances in all of the subspecialties of the broad area of molecular toxicology. Toxicology is the study of poisons, and this series details the study of the molecular basis by which a vast array of agents encountered in the human environment and produced by the human body itself manifest themselves as toxins. Not strictly limited to documenting these examples, the series is also concerned with the complex web of chemical and biological events that give rise to toxin-induced symptoms and disease. The new technologies that are being harnessed to analyze and understand these events will also be reviewed by leading workers in the field.
"Advances in Molecular Toxicology" will report progress in all aspects of these rapidly evolving molecular aspects of toxicology with a view toward detailed elucidation of both progress on the molecular level and on advances in technological approaches employed.
* Cutting-edge reviews by leading workers in the discipline
* In-depth dissection of molecular aspects of interest to a broad range of scientists, physicians and any student in the allied disciplines
* Leading edge applications of technological innovations in chemistry, biochemistry and molecular medicine

Aquatic toxicology is the study of the effects of manufactured chemicals and other anthropogenic and natural materials and activities on aquatic organisms at various levels of organization, from subcellular through individual organisms to communities and ecosystems. This book presents the latest research in this field from around the globe.

Food Toxicants Analysis covers different aspects from the field of analytical food toxicology including emerging analytical techniques and applications to detect food allergens, genetically modified organisms, and novel ingredients (including those of functional foods). Focus will be on natural toxins in food plants and animals, cancer modulating substances, microbial toxins in foods (algal, fungal, and bacterial) and all groups of contaminants (i.e., pesticides), persistent organic pollutants, metals, packaging materials, hormones and animal drug residues. The first section describes the current status of the regulatory framework, including the key principles of the EU food law, food safety, and the main mechanisms of enforcement. The second section addresses validation and quality assurance in food toxicants analysis and comprises a general discussion on the use of risk analysis in establishing priorities, the selection and quality control of available analytical techniques. The third section addresses new issues in food toxicant analysis including food allergens and genetically modified organisms (GMOs). The fourth section covers the analysis of organic food toxicants.
* step-by-step guide to the use of food analysis techniques
* eighteen chapters covering emerging fields in food toxicants analysis
* assesses the latest techniques in the field of inorganic analysis

This volume studies the risk to the environment and human health posed by nitroPAHS. Data on the in vivo genotoxicity of nitroPAHs are available for 15 nitroPAHs. All nitroPAHs that gave positive results in vivo were also positive in vitro. Four nitroPAHs that were positive in in vitro genotoxicity tests revealed inconsistent or inconclusive genotoxicity (2-nitronaphthalene, 5-nitroacenaphthene and 3-nitrofluoranthene) or negative genotoxicity (2,7-dinitrofluorene; limited validity) results in vivo. There are no reports on the effects of individual nitroPAHs on humans. As would be expected, since nitroPAHs occur in complex mixtures in the atmosphere and exhaust, the exact contribution of nitroPAHs to the adverse health consequences of exposure to polluted atmospheres and to exhaust cannot be elucidated.

Palladium is a steel-white, ductile metallic element resembling and occurring with the other platinum group metals and nickel. Palladium and its alloys are used in the (petro) chemical and the automotive industries as catalysts, in dentistry, and in electronics and the, electrical industry.This book evaluates the risks to human health and the environment posed by exposures to palladium. The general population is primarily exposed to palladium through dental alloys or jewellery. There were case reports referring to palladium sensitivity associated with exposure to palladium-containing dental restorations; the, symptoms being contact dermatitis, stomatitis or mucositis and oral lichen planus.Palladium ions are considered to be highly toxic to aquatic organisms. However, due to palladium's high economic value, emissions of palladium from point sources are currently minimal. Increased use of catalytic converters may increase palladium emissions from diffuse sources. It was recommended that these emissions should, be controlled to be as low as possible.

This book evaluates the risk to human health and the environment posed by exposures to fluorides. It is widely known that fluoride has both positive and negative effects on human health, and there is a narrow range between intakes that are associated with these effects. Cases of skeletal fluorosis associated with the consumption of drinking water containing elevated levels of fluoride are reported. Fluoride is ubiquitous in the environment and virtually all foodstuffs contain at least trace amounts of fluoride. The amount of fluoride present naturally in non-fluoridated drinking water is highly variable, being dependent upon the individual geological environment. Also, fluorides, especially hydrogen fluoride, are important industrial compounds and they are used in aluminium production, glass manufacturing and so on. This document focuses on environmental exposure to fluoride derived mostly from inorganic sources and its effects on humans, animals and other biota.Data on hydrogen fluoride, calcium fluoride, sodium fluoride, sulfur hexafluoride and silicofluorides are covered, as these compounds are considered to be the most relevant of the inorganic fluorides on the basis of quantities released to the environment, environmental concentrations and toxicological effects on living organisms. A review of studies on the environmental fate and concentration of fluorides is also presented in this document.

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.

Evaluates the carcinogenic risks to humans posed by exposure to X- and g-radiation and to neutrons from external sources. The book opens with a general introduction to nomenclature, dosimetric methods and models in the occupational and environmental settings, the behaviour of radiation in biological tissues, and sources of human exposure. Natural background radiation is identified as by far the largest source of exposure for the world's population. The medical use of X-rays and radiopharmaceuticals constitutes the next most significant source, followed by exposure from atmospheric testing of nuclear weapons. The collective doses from other sources of radiation are considered much less important. The first and most monograph, on X- and g-radiation, reviews the large body of evidence arising from the extensive investigation of carcinogenic effects in humans, mainly in survivors of the atomic bombings in Japan and patients exposed to radiation for medical reasons. In both groups, an excess number of cases of leukaemia and other cancers have been observed.Irradiation during childhood increases the risk of thyroid cancer, while an increase in breast cancer risk has been observed after irradiation of pre-menopausal women. X-rays and g-rays have also been tested for carcinogenicity at various doses and under various conditions in a range of animal species. In adult animals, the incidences of leukaemia and of mammary, lung, and thyroid tumours were increased in a dose-dependent manner with both types of radiation. Prenatal exposure also gave rise to increased incidences of various types of tumours. On the basis of this evidence, the monograph concludes that X-radiation and g-radiation are carcinogenic to humans. The carcinogenic risk to humans posed by exposure to neutrons is evaluated in the second monograph, which concentrates on risks associated with the exposure of patients to neutron radiotherapy beams and exposures of aircraft passengers and crew. In high-altitude cities, neutrons can constitute as much as 25% of background radiation. Neutrons from various sources with wide ranges of mean energy have been tested for carcinogenicity in different animal species, and at various doses and dose rates.In adult animals, the incidences of leukaemia and ovarian, mammary, lung, and liver cancer were increased in a dose-related manner. Prenatal and parental exposure resulted in increased incidences of liver tumours in the offspring. In virtually all studies, neutrons were more effective in inducing tumours than were X-rays and g-rays when compared on the basis of absorbed dose. Although no adequate human carcinogenicity data were available for assessment, the monograph used other relevant data, including evidence of DNA damage, to reach the conclusion that neutrons are carcinogenic to humans.

Evaluates or re-evaluates the carcinogenic risks to humans posed by exposure to sixteen organic industrial chemicals. These included some aromatic amines (ortho-toluidine, 4-chloro-ortho-toluidine, and 5-chloro-ortho-toluidine), some ethanolamines (di- and triethanolamine and N-nitrosodiethanolamine), and three esters [di(2-ethylhexyl) phthalate (DEHP), di(2-ethylhexyl) adipate, and cinnamyl anthranilate]. Seven of the sixteen compounds were evaluated in previous IARC Monographs and are reconsidered here in the light of new evidence. Three chemicals were classified or reclassified as probably carcinogenic to humans: ortho-toluidine, 4-chloro-ortho-toluidine, and glycidol. Four compounds, evaluated here for the first time, namely 2,2-bis(bromomethyl)propane-1,3-diol, 2,3-dibromopropan-1-ol, ethylbenzene, and nitromethane, were classified as possibly carcinogenic to humans. N-Nitrosodiethanolamine, which can readily be formed from either di- or triethanolamine in the presence of inorganic nitrite, remained classified as possibly carcinogenic to humans.For eight compounds, including 5-chloro-ortho-toluidine, coumarin, pyridine, diethanolamine, triethanolamine, di(2-ethylhexyl) adipate, and cinnamyl anthranilate, evidence was judged inadequate to classify these compounds according to their carcinogenicity in humans. The most extensive monograph is devoted to an evaluation of di(2-ethylhexyl) phthalate (DEHP), which had previously been classified as possibly carcinogenic to humans. Using assessment criteria recently established for compounds that induce peroxisome proliferation in the liver, the evaluation downgraded DEHP to the group of compounds that cannot be classified. Two other compounds that cause peroxisome proliferation, di(2-ethylhexyl) adipate and cinnamyl anthranilate, were also evaluated as not classifiable as to carcinogenicity to humans.

This book evaluates the risks to human health posed by disinfectants and disinfectant by-products found in treated drinking water. Noting that chlorine and other widely used disinfectants were approved for use almost 100 years ago when toxicological data were limited, the report responds to the need for reassurance that consumption of treated drinking water will not have adverse effects on health. Particular concern centers on the potential of chlorine to react with natural organic matter and form a large number of by-products, some of which have been intensively studied as potential human carcinogens. With these concerns in mind, the report evaluates over 800 recent studies in an effort to clarify understanding of the chemistry and toxicology of disinfectants and disinfectant by-products and provide a balanced assessment of the associated risks to human health. The report is issued at a time when public health authorities and utilities-providers in several countries are considering alternative methods of disinfection aimed at reducing the formation of specific by-products. In this context, the report stresses the overriding importance of microbiological safety and warns that adequate disinfection must not be compromised by efforts to control chemical by-products. The first chapter on the chemistry of disinfectants and disinfectant by-products examines the many complex factors, including methods of water treatment that govern the formation of by-products and influence their type and amount. Of special interest to utilities-providers, the chapter explains the physical and chemical properties that influence the behavior of specific by-products in drinking water and determine their toxic actions. By-products of greatest concern are identified as trihalomethanes including chloroform and bromodichloromethane, haloacetic acids including dichloroacetic acid, and trichloroacetic acid, bromate, and chlorite. The chapter concludes that the adoption of alternative disinfecting chemicals often amounts to nothing more than a trade-off between one group of by-products and another. Removal of natural organic matter is singled out as the most effective control strategy. Chapter two reviews what is known about the toxic effects of the principal disinfectants: chlorine and hypochlorite, chloramines, and chlorine dioxide. On the basis of this evaluation, the report concludes that disinfectants probably do not increase the risk of cancer or have other significant adverse effects on health. Chapter three evaluates the toxic effects of fourteen by-products, concentrating on the large number of studies of carcinogenicity and mutagenicity. Epidemiological studies are reviewed in chapter four, which considers extensive investigations of possible associations with cancer, cardiovascular disease, and adverse effects on reproduction and development. While most studies have concentrated on an increased risk of bladder cancer, risks of colon, rectal, and other cancers have also been investigated. Noting the uncertainties surrounding many of these studies, the report cautions against a simple interpretation of observed associations and concludes that more comprehensive water quality data must be collected to improve exposure assessments. Evidence was considered insufficient to determine whether observed associations are causal and which specific by-products or other contaminants play a role. In the final chapters focused on risk, characterization, and assessment, the report concludes that the risks to health from disinfectant by-products at the levels at which they occur in drinking water are extremely small in comparison with the risks associated with inadequate disinfection. In supporting efforts to minimize the formation of by-products, the report further concludes that protection of source waters aimed at reducing the presence of natural organic matter is often the most efficient approach to control.

Natural toxins form a major component of the molecular tools used increasingly frequently by the ever growing number of laboratories of various kinds. Evidence for this is provided not only by the increasing number of firms including such toxins in their catalogues but also by the large number of demands received by those who discover new toxins. Twenty chapters survey important aspects of toxin origin, their structure and molecular mechanism, and their cellular and pathogenic effects. In addition, the text provides comprehensive and specific methodology for the application of these toxins in the research laboratory. This begins with the description of the method of extraction, biochemical and pharmacological characterization, and assessment of purity, and continues with methods for chemical modification, e.g. labelling, and eventually describes applications in pharmacological studies in vivo and/or in vitro. The length of this book has been kept reasonable by concentrating on animal toxins,...

This book evaluates the risks to human health and the environment posed by the use of Bacillus thuringiensis (Bt) as a microbial agent for pest control. Products containing various Bt subspecies are increasingly used worldwide to control the larvae of several insect pests that threaten major agricultural crops and forests. Bt products are also being used to control the insect vectors of malaria onchocerciasis and other diseases of major public health importance. The bacterium is also a key source of genes for transgenic expression to provide pest resistance in plants and microorganisms. The report opens with an overview of the biological properties of Bt and commercial Bt products. Particular attention is given to the mechanisms by which sporulation produces inclusion bodies containing insecticidal crystalline proteins which are selectively toxic for insect species in the orders Coleoptera Diptera and Lepidoptera. Tables show the current classification of 67 Bt subspecies and the large number of genes coding for the insecticidal crystalline proteins. A review of Bt metabolites found in commercial products concludes that they pose no hazards to humans or the environment. Chapter two reviews data elucidating the mechanisms by which Bt exerts its toxic action on susceptible insect larvae. Data on insect populations that are resistant to Bt are also briefly considered. Chapter three which focuses on the survival and activity of Bt in the environment compares habitats where Bt subspecies occur naturally with treated habitats. Particular attention is given to the ability of Bt to form endospores that are resistant to inactivation by heat and desiccation and that persist in the environment under adverse conditions. A chapter on commercial production describes methods of production and general patterns of use in agriculture and forestry and in large-scale programmes to control the vectors of malaria and onchocerciasis. The most extensive chapter evaluates the large number of studies conducted to assess the toxicity of various preparations containing insecticidal crystalline proteins spores and vegetative cells. Laboratory studies in a range of species have failed to demonstrate toxic or pathogenic effects. Field studies have likewise failed to demonstrate adverse effects on birds earthworms fish other aquatic vertebrates and non-target aquatic invertebrates. An evaluation of effects on humans draws on studies in volunteers case reports from occupationally-exposed workers and extensive data from countries where Bt products are added to drinking-water for mosquito control or used to treat rivers for blackfly control. On the basis of this review the report concludes that Bt products are unlikely to pose any hazard to humans or other vertebrates or to the great majority of non-target invertebrates provided the commercial product is free from non-Bt microorganisms and biologically active products other than the insecticidal crystalline proteins. The report further concludes that Bt products can be safely used for the control of insect pests of agricultural and horticultural crops and forests. These products are likewise judged safe for use in aquatic environments including drinking-water reservoirs for the control of mosquito black fly and nuisance insect larvae. The report stresses however that vegetative Bt has the potential to produce Bacillus cereus-like toxins whose significance as a possible cause of human gastrointestinal disease remains unknown. ...one of the most thorough published reviews of Bacillus thuringiensis ... provides an array of pertinent background material... -- Integrated Pest Management Network

Reviews of Environmental Contamination and Toxicology provides detailed review articles concerned with aspects of chemical contaminants, including pesticides, in the total environment with toxicological considerations and consequences. C.E. CASTRO: Environmental Dehalogenation-Chemistry and Mechanism M.J. KENNISH: Trace Metal-Sediment Dynamics in Estuaries: Pollution Assessment R.D. VINEBROOKE AND R. CULLIMORE: Natural Organic Matter and the Bound Water Concept in Aquatic Ecosystems

Reviews of Environmental Contamination and Toxicology attempts to provide concise, critical reviews of timely advances, philosophy, and significant areas of accomplished or needed endeavor in the total field of xenobiotics, in any segment of the environment, as well as toxicological implications.

Commercial Biosensors offers professionals an in-depth look at some of the most significant applications of commercially available biosensor-based instrumentation in the medical, bioprocess, and environmental fields. Featuring contributions by an international team of scientists, the book provides readers with an unparalleled opportunity to see how their colleagues around the world are using these powerful new tools.
Commercial Biosensors is divided into three sections. In the first, which is devoted to applications of biosensors to clinical samples, the authors explore how biosensors are currently being used for in-home diabetes monitoring, point-of-care diagnostics, and noninvasive sensing, and biomedical research. The second section deals with cutting-edge applications of biosensors in bioprocess control- for example, measuring glucose, sucrose, glutamate, or choline concentrations during food and beverage production and measuring ethanol concentration during beer fermentation. In the final section, readers learn about the use of biological oxygen demand (BOD) biosensors for monitoring environmental samples.
This book is an indispensable addition to the reference libraries of biosensor technologists, physicians, analytical chemists, environmental engineers, pesticide chemists, clinical chemists, and food chemists.
An in-depth exploration of state-of-the-art commercial biosensor technology and its aplications.
Commercial biosensor technology has taken off over the past few years, and the number of applications is growing rapidly. This book offers professionals a timely and authoritative look at some of the most important of these applications. Over the course ofseven chapters authored by leading international experts, readers learn all about the latest in:
* Biosensors and diabetes management
* Microfabricated biosensors and point-of-care diagnostics systems
* Noninvasive biosensors in clinical analysis
* Surface plasmon resonance and evanescent wave biosensors
* Biosensor-based instruments in food and beverage production
* Biosensors in environmental sampling
Commercial Biosensors is required reading for all professionals who would like to take advantage of the enormous potential of one of today's most important new commercial technologies.

Environmental toxicology and chemistry have become subjects of intense academic and public interest. This book is the first text to tie them closely together. It presents their principles and applications through numerous illustrative examples and special topics highlighting current environmental concerns. Intended for advanced undergraduate and graduate students, the book will also interest anyone desiring an update in these timely subjects.

This addition to the Advances in Environmental Control Technology Series contains 23 chapters designed to provide an extensive overview and reference on human physiological responses to various forms of pollution.

Developments in the understanding of herbicide activity and toxicology have expanded tremendously in the past fifteen years. Research on the mechanism of action of most major classes of herbicide chemistry has provided scientists with excellent insight into enzyme targets. More recently, developments in molecular biology have provided information about herbicide action at the genetic level. Less well understood are the toxicological aspects of herbicide activity that culminate in plant injury or death. Toxicology, Biochemistry and Molecular Biology of Herbicide Activity is a review of the recent literature on most of the major classes of herbicide chemistry in commercial use. The chapters include information about different aspects of herbicide activity related to photosynthesis, inhibition of amino acid biosynthesis, disruption of cell division and microtubule assembly, activity of phytohormone (auxin) mimics, inhibition of fatty acid biosynthesis and some developments in the understanding of herbicide resistance.

Issues authoritative recommendations concerning nutritional requirements and safe ranges of intake for nineteen trace elements important to human health. Representing the consensus reached by a large number of international experts, the book aims to give scientists and those responsible for nutrition planning a solid basis for assessing dietary intakes of trace elements, detecting deficiencies and excesses, and recognizing the clinical features of related disorders. Throughout, guidelines and advice respond to greatly expanded knowledge about the significant impact that even subtle differences in trace elements can have on health and disease. The core of the report, which has three parts, provides authoritative recommendations on the nutritional significance, requirements for health, and safe range of daily intakes for nineteen trace elements in three categories. These include essential elements, such as iodine and zinc, probably essential elements, such as manganese and silicon, and potentially toxic elements, such as fluoride, lead, cadmium and mercury, which may also have some essential functions at low levels.