Arsenic is a metalloid widely distributed in the earth's crust. Inorganic arsenic of geological origin is found in groundwater used as drinking-water in several parts of the world. Arsenic is emitted into the atmosphere by high-temperature processes such as coal-fired power generation plants, burning vegetation and volcanism. Soluble inorganic arsenic is acutely toxic and ingestion of large doses leads to gastrointestinal symptoms, disturbances of cardiovascular and nervous system functions, and eventually death. In survivors, bone marrow depression, haemolysis, hepatomegaly, melanosis, polyneuropathy and encephalopathy may be observed.
- Arsenic exposure via drinking-water is causally related to cancer in the lungs, kidney, bladder and skin: drinking-water arsenic concentrations of Ã‚Â£ 50 Ã‚Âµg/liter have been associated with increased risks of cancer in the bladder and lung, while precursors of skin cancer have been associated with drinking-water arsenic levels < 50 Ã‚Âµg/liter.
- Occupational exposure to airborne arsenic is causally related to cancer of the lung, with cumulative exposure to Ã‚Â³ 0.75 mg/m3 Ãƒâ€” year associated with an increased risk of lung cancer.
- Arsenic is considered to be genotoxic in humans on the basis of clastogenicity in exposed individuals and findings in vitro.
- Arsenic exposure via drinking-water induces peripheral vascular disease
- . Whether arsenic alone is sufficient to cause the extreme form of this disease, blackfoot disease, is not known.
- Conclusions on the causality of the relationship between arsenic exposure and other health effects are less clear-cut. The evidence is strongest for hypertension and cardiovascular disease, suggestive for diabetes and reproductive effects and weak for cerebrovascular disease, long-term neurological effects and cancer at sites other than lung, bladder, kidney and skin.