Environmental pollutants that cause cancer
Several environmental factors often present serious risks for human health. A growing body of evidence links exposure to certain environmental and occupational pollutants to cancer.
Examples of these include (but are not limited to):
Polluted drinking water
Water is essential to sustain life. Poor water quality continues to pose a major threat to human health. Diarrhoeal disease alone is responsible for 1.8 million deaths every year (2004 data). Several microbial, chemical and radiological factors (naturally occurring radionuclides such as radon) contribute to poor water quality.
Poor (indoor) air quality
Polluted air is responsible for an estimated 3.1 millions deaths worldwide every year. Air pollutants have been linked to a range of health problems such as respiratory infections, cardiovascular diseases, lung cancer and many others.
Chemical pollutants (such as asbestos)
Asbestos exposure mostly occurs through inhalation of fibres in the working environment, but also through inhalation of air in the vicinity of sources such as factories handling asbestos or indoor air in houses and buildings containing asbestos. Today, about 125 million people worldwide are exposed to asbestos at their workplace. Asbestos inhalation causes lung cancer, mesothelioma, cancer of the larynx and ovary and asbestosis (fibrosis of the lungs). In 2004, asbestos-related lung cancer, asbestos-related lung cancer, mesothelioma and asbestosis from workplace exposure resulted in 107,000 deaths. In addition, several thousands of deaths can be attributed to other asbestos-related diseases, as well as to non-occupational exposures.
Food chemicals (such as dioxins)
Human exposure to dioxins and dioxin-like substances has been associated with a range of toxic effects, including immunotoxicity, developmental and neurodevelopmental effects, changes in thyroid and steroid hormones and reproductive function.
Ionizing radon radiation
Radon, a natural gas that escapes from the ground and surface water, is the most prominent source of environmental radioactivity. While there is usually a rather low outdoor concentration, radon tends to concentrate in houses. Exposure to radon is the second leading cause of lung cancer, after smoking. In the US, radon causes about 21,000 lung cancer deaths every year (out of a total of about 160,000 annual lung cancer deaths).