Chemicals are part of our daily life. All living and inanimate matter is made up of chemicals and virtually every manufactured product involves the use of chemicals. Many chemicals can, when properly used, significantly contribute to the improvement of our quality of life, health and well-being. But other chemicals are highly hazardous and can negatively affect our health and environment when improperly managed.
The production and use of chemicals continues to grow worldwide, particularly in developing countries. This is likely to result in greater negative effect on health if sound chemicals management is not ensured. Multisectoral action is urgently needed to protect human health from the harmful effects of improperly managed chemicals. WHO provides scientific evidence and risk management recommendations for 10 chemicals or groups of chemicals of major public health concern.
Arsenic is a metalloid element that forms a number of poisonous compounds. It is widely distributed throughout the Earth’s crust, and can be released into the atmosphere and water through natural and human activities.
All types of asbestos cause lung cancer, mesothelioma, cancer of the larynx and ovary, and asbestosis (fibrosis of the lungs). Exposure to asbestos occurs through inhalation of fibres in air in the working environment, ambient air in the vicinity of point sources such as factories handling asbestos, or indoor air in housing and buildings containing friable (crumbly) asbestos materials.
Human exposure to benzene has been associated with a range of acute and long-term adverse health effects and diseases, including cancer and haematological effects. Exposure can occur occupationally, in the general environment and in the home as a result of the ubiquitous use of benzene-containing petroleum products, including motor fuels and solvents. Active and passive exposure to tobacco smoke is also a significant source of exposure.
Cadmium exerts toxic effects on the kidneys as well as the skeletal and respiratory systems. It is classified as a human carcinogen. It is generally present in the environment at low levels; however, human activity has greatly increased levels in environmental media relevant to population exposure. Exposures potentially of particular concern for children include disposal and recycling of electronic and electrical waste, as well as toys, jewellery and plastics containing cadmium.
Dioxins and dioxin-like substances, including PCBs, are persistent organic pollutants (POPs) covered by the Stockholm Convention. They can travel long distances from the source of emission, and bioaccumulate in food chains.
Fluoride intake has both beneficial effects – in reducing the incidence of dental caries – and negative effects – in causing tooth enamel and skeletal fluorosis following prolonged high exposure. The ranges of intakes producing these opposing effects are not far apart.
Lead is a toxic metal whose widespread use has caused extensive environmental contamination and health problems in many parts of the world. It is a cumulative toxicant that affects multiple body systems, including the neurologic, hematologic, gastrointestinal, cardiovascular, and renal systems. Children are particularly vulnerable to the neurotoxic effects of lead, and even relatively low levels of exposure can cause serious and in some cases irreversible neurological damage.
Mercury is toxic to human health, posing a particular threat to the development of the child in utero and early in life. Mercury exists in various forms: elemental (or metallic); inorganic (e.g. mercuric chloride); and organic (e.g., methyl- and ethylmercury), which all have different toxic effects, including on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.
Highly hazardous pesticides may have acute and/or chronic toxic effects, posing particular risk to children, and are recognized as an issue of global concern. Their widespread use has caused health problems and fatalities in many parts of the world, often as a result of occupational exposure and accidental or intentional poisonings.
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The 10 chemicals of public health concern:
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