Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than that of water. Their multiple industrial, domestic, agricultural, medical, and technological applications have led to their wide distribution in the environment, raising concerns over their potential effects on human health and the environment. Their toxicity depends on several factors including the dose, route of exposure, and chemical species, as well as the age, gender, genetics, and nutritional status of exposed individuals. Because of their high degree of toxicity, arsenic, cadmium, chromium, lead, and mercury rank among the priority metals that are of public health significance. These metallic elements are considered systemic toxicants that are known to induce multiple organ damage, even at lower levels of exposure. They are also classified as human carcinogens (known or probable) according to the US Environmental Protection Agency and the International Agency for Research on Cancer. This review provides an analysis of their environmental occurrence, production and use, potential for human exposure, and molecular mechanisms of toxicity, genotoxicity, and carcinogenicity.

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Heavy metal toxicity and the environment.

Advances in metal-induced oxidative stress and human disease

9.2. Protein-Based Hg(II) Detectors 3467 9.3. Oligonucleotide-Based Hg(II) Detector 3467 9.4. DNAzyme-Based Hg(II) Detectors 3469 9.5. Antibody-Based Hg(II) Detector 3469 10. Mercury Detectors Based on Materials 3469 10.1. Soluble and Fluorescent Polymers 3469 10.2. Membranes, Films, and Fibers 3471 10.3. Micelles 3473 10.4. Nanoparticles 3473 11. Perspectives 3474 12. Addendum 3475 12.1. Small Molecules 3475 12.2. Biomolecules 3477 12.3. Materials 3477 13. List of Abbreviations 3477 14. Acknowledgments 3478 15. References 3478

Tools and tactics for the optical detection of mercuric ion.

This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."

The Toxicology of Mercury and Its Chemical Compounds

Exposure to even very low levels of lead, cadmium, and mercury ions is known to cause neurological, reproductive, cardiovascular, and developmental disorders, which are more serious problems for children particularly. Accordingly, great efforts have been devoted to the development of fluorescent and colorimetric sensors, which can selectively detect lead, cadmium, and mercury ions. In this critical review, the fluorescent and colorimetric sensors are classified according to their receptors into several categories, including small molecule based sensors, calixarene based chemosensors, BODIPY based chemosensors, polymer based chemosensors, DNA functionalized sensing systems, protein based sensing systems and nanoparticle based sensing systems (197 references).

Fluorescent and colorimetric sensors for detection of lead, cadmium, and mercury ions

ercury has been used commercially and medically for centuries. In the past it was a common constituent of many medications. It is still used in hospitals in thermometers and blood-pressure cuffs and commercially in batteries, switches, and fluorescent light bulbs. Large quantities of metallic mercury are employed as electrodes in the electrolytic production of chlorine and sodium hydroxide from saline. These uses still give rise to accidental and occupational exposures. 1 Today, however, exposure of the general population comes from three major sources: fish consumption, dental amalgams, and vaccines. Each has its own characteristic form of mercury and distinctive toxicologic profile and clinical symptoms. Dental amalgams emit mercury vapor that is inhaled and absorbed into the bloodstream. Dentists and anyone with an amalgam filling are exposed to this form of mercury. Liquid metallic mercury (quicksilver) still finds its way into homes, causing a risk of poisoning from the vapor and creating major cleanup costs. Humans are also exposed to two distinct but related organic forms, methyl mercury (CH 3 Hg + ) and ethyl mercury (CH 3 CH 2 Hg + ). Fish are the main if not the only source of methyl mercury, since it is no longer used as a fungicide. In many countries, babies are exposed to ethyl mercury through vaccination, since this form is the active ingredient of the preservative thimerosal used in vaccines. Whereas removal of certain forms of mercury, such as that in blood-pressure cuffs, will not cause increased health risks, removal of each of the three major sources described in this article entails health risks and thus poses a dilemma to the health professional. Exposure to mercury from dental amalgams and fish consumption has been a concern for decades, but the possible risk associated with thimerosal is a much newer concern. These fears have been heightened by a recent recommendation by the Environmental Protection Agency (EPA) that the allowable or safe daily intake of methyl mercury be reduced from 0.5 µg of mercury per kilogram of body weight per day, the threshold established by the World Health Organization in 1978, 2 to 0.1 µg of mercury per kilogram per day. 3 Table 1 summarizes the clinical toxicologic features of mercury vapor and methyl and ethyl mercury. It also includes data on inorganic divalent mercury, since this is believed to be the toxic species produced in tissues after inhalation of the vapor. 5 It is also responsible for kidney damage after exposure to ethyl mercury, since ethyl mercury is rapidly converted to the inorganic form. 13 Inorganic mercury as both mercuric and mercurous salts was also the chief cause of acrodynia, a childhood disease that is now mainly of historical interest. 14 The clinical symptoms of acrodynia consist of painful, red, swollen fingers and toes in association with photophobia, irritability, asthenia, and hypertension. It is believed to be a hypersensitivity reaction. m

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The toxicology of mercury--current exposures and clinical manifestations.

GENERAL AND CLINICAL ASPECTS, RISK ASSESSMENT, AND GENOTOXICITY OF METALS Monitoring, Environmental, and Health Risk Assessments (Anna M. Fan) An Introduction to Monitoring and Environmental and Human Risk Assessment of Metals (Anna M. Fan) Monitoring and Assessment of Metal Contaminants in the Air (Josef M. Pacyna) Assessment of Ecological and Health Effects of Soil-Borne Trace Elements and Metals (A.C. Chang and A.L. Page) Assessment of Metals in Drinking Water With Specific References to Lead, Copper, Arsenic, and Selenium (Anna M. Fan) Risk Assessment of Metals (J. Michael Davis and Robert W. Elias) Techniques Employed for the Assessment of Metals in Biological System (Richard M. Jacob) Concepts on Biological Markers and Biomonitoring for Metal Toxicity (Lars Gerhardsson and Staffan Skerfving) Bioresponses and Reactivities to Metal Toxicity An Introduction to Bioresponses and Reactivities of Metals (Louis W. Chang) Determinants of Reactivity in Metal Toxicity (Evert Nieboer and Glenn G. Fletcher) Metals and Biological Membranes (Ernest C. Foulkes) Interactions Between Glutathione and Mercury in the Kidney, Liver, and Blood (Rudolfs K. Zalups and Lawrence H. Lash) The Role of General and Metal-Specific Cellular Responses in Protection and Repair of Metal-Induced Damage: Stress Proteins and Metallothioneins (Brenda M. Sanders, Peter L. Goering, and Kenneth Jenkins) Metal-Metal Interactions (Anada S. Prasad and Frances W. J. Beck) Carcinogenesis and Genotoxicity of Metals Part A: Carcinogenicity and Genotoxicity of Specific Metals An Introduction to Metal Toxicity and Carcinogenicity of Metals (Max Costa) Carcinogenicity and Genotoxicity of Chromium (Catherine B. Klein) The Carcinogenicity of Arsenic (Zaolin Wang and Toby G. Rossman) Cadmium Carcinogenicity and Genotoxicity (Michael P. Waalkes and R. Rita Misra) Mechanisms of Nickel Genotoxicity and Carcinogenicity (Max Costa) Carcinogenicity and Genotoxicity of Lead, Beryllium, and Other Metals (Mitchell D. Cohen, Darlene H. Bowser, and Max Costa) Part B: Selected Concepts in Metal Carcinogenesis An Introduction to Selected Concepts in Metal Carcinogenesis (Lionel A. Poirier) Metal Interactions in Chemical Carcinogenesis (Lionel A. Poirier and Neil A. Littlefield) Oxidative DNA Damage in Metal-Induced Carcinogenesis (Kazimierz S. Kasprzak) Metal-Induced Gene Expression and Neoplastic Transformation (Joseph R. Landolph, Michael Dews, Laurent Ozbun, and Douglas Parker Evans) Clinical Aspects of Metal Toxicity An Introduction to Clinical Aspects of Metal Toxicity (Kazuo T. Suzuki and Tsuguyoshi Suzuki) Minamata Disease and Other Mercury Syndromes (Rikuzo Hamada and Mitsuhiro Osame) Itai-Itai Disease and Health Effects of Cadmium (Koji Nagawa and Teruhiko Kido) Genetic Disorders of Copper Metabolism (Hiroko Kodama) Alzheimer's Disease and Other Aluminum-Associated Health Conditions (D.R. McLachlan, P.E. Fraser, E. Jaikaran, and W.J. Lukiw) Current Status of Childhood Lead Exposure at Low Dose (Herbert L. Needleman) Neurological Aspects in Human Exposure to Manganese (Naohide Inoue and Yuji Makita) Health Effects of Arsenic (Ganzalo G. Garcia-Vargas and Mariano E. Cebrian) Toxicity of Bismuth and Its Compounds (Anja Slikkerveer and Frederik A. de Wolff) Human Exposure to Lithium, Thallium, Antimony, Gold, and Platinum (G.B. van der Voet and Frederik A. de Wolff) Cobalt and Nickel Induced Hard Metal Asthma (Yukinori Kusaka) Aspects on Health Risks of Mercury from Dental Amalgams (Jan A. Weiner and Magnus Nylander) Chelation Therapies for Metal Intoxication (Carol R. Angle)

Toxicology of metals

(1980). The interactions of selenium with cadmium and mercury. CRC Critical Reviews in Toxicology: Vol. 8, No. 1, pp. 1-42.

The interactions of selenium with cadmium and mercury

Mercury is ubiquitous in the environment and therefore every human being, irrespective of age and location, is exposed to one form of mercury or another. The major source of environmental mercury is natural degassing of the earth's crust, but industrial activities can raise exposure to toxic levels directly or through the use or misuse of the liquid metals or synthesized mercurial compounds. The aim of this review is to survey differences in human exposure and in the toxicology of different forms of mercury. It covers not only symptoms and signs observed in poisoned individuals by a clinician but also subclinical effects in population studies, the final evaluation of which is the domain of statisticians.

http://acb.sagepub.com/content/43/4/257.full.pdf

Laszlo Magos

Papers

The Toxicology of Mercury and Its Chemical Compounds

The toxicology of mercury--current exposures and clinical manifestations.

Toxicology of metals

The interactions of selenium with cadmium and mercury

Overview of the clinical toxicity of mercury.