Elimination is rapid at first (half-life of 1–2 days), by methylation to monomethylarsonic acid and dimethylarsinic acid, and excretion in the urine, but a certain amount (30–40% in the case of repeated exposure) is incorporated into the bones, the muscles, the skin, the hair and 
the nails (all tissues rich in keratin) and eliminated over a period of weeks or months. The first symptoms of acute arsenic poisoning by ingestion are digestive problems: vomiting, abdominal pains, diarrhea often accompanied by bleeding. Sub-lethal doses can lead to convulsions, cardiovascular problems, inflammation of the liver and kidneys and abnormalities in the coagulation of the blood. These are followed by the appearance of characteristic white lines (Mees lines) on the nails and by hair loss. Lower doses lead to liver and kidney problems and to changes in the pigmentation of the skin. Even dilute solutions of arsenic trioxide are dangerous on contact with the eyes. The poisonous properties are well known and the subject of an extensive literature.Chronic arsenic poisoning is known as arsenicosis. This disorder affects workers in smelters, in populations whose drinking water contains high levels of arsenic (0.3–0.4 ppm), and in patients treated for long periods with arsenic-based pharmaceuticals. Similarly, studies on workers exposed in copper foundries in the U.S., Japan and Sweden indicate a risk of lung cancer 6–10 times higher for the most exposed workers compared with the general population. Long-term ingestion of arsenic trioxide either in drinking water or as a medical treatment can lead to skin cancer.
For example, the Giant Mine in Canada processed substantial amounts of arsenopyrite-contaminated gold ores. References
External links
"Arsenic trioxide". Drug Information Portal. U.S. National Library of Medicine. Case Studies in Environmental Medicine: Arsenic Toxicity
"Arsenic and Arsenic Compounds". Summaries & Evaluations. International Agency for Research on Cancer (IARC). February 1998.
International Chemical Safety Card 0378
Safety Data Sheet from American Elements
NIOSH Pocket Guide to Chemical Hazards
NTP Report on Carcinogens – Inorganic Arsenic Compounds
Institut national de recherche et de sécurité (1989). "Trioxyde darsenic." Fiche toxicologique n° 89. Paris:INRS. (in French)