Arsenic round the world: a review.

Arsenic toxicity and potential mechanisms of action

Ingestion of arsenic, both from water supplies and medicinal preparations, is known to cause skin cancer. The evidence assessed here indicates that arsenic can also cause liver, lung, kidney, and bladder cancer and that the population cancer risks due to arsenic in U.S. water supplies may be comparable to those from environmental tobacco smoke and radon in homes. Large population studies in an area of Taiwan with high arsenic levels in well water (170-800 micrograms/L) were used to establish dose-response relationships between cancer risks and the concentration of inorganic arsenic naturally present in water supplies. It was estimated that at the current EPA standard of 50 micrograms/L, the lifetime risk of dying from cancer of the liver, lung, kidney, or bladder from drinking 1 L/day of water could be as high as 13 per 1000 persons. It has been estimated that more than 350,000 people in the United States may be supplied with water containing more than 50 micrograms/L arsenic, and more than 2.5 million people may be supplied with water with levels above 25 micrograms/L. For average arsenic levels and water consumption patterns in the United States, the risk estimate was around 1/1000. Although further research is needed to validate these findings, measures to reduce arsenic levels in water supplies should be considered.

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Cancer risks from arsenic in drinking water.

Arsenic Exposure and Toxicology: A Historical Perspective

Toxicological profile for arsenic

Metabolism of arsenobetaine in mice, rats and rabbits

Intracellular interaction and metabolic fate of arsenite and arsenate in mice and rabbits

Effects of low dietary intake of methionine, choline or proteins on the biotransformation of arsenite in the rabbit.

The metabolism of dimethylarsinic acid (DMA) a common pesticide and the main metabolite of inorganic arsenic in mammals, has been studied in mice, hamsters and man. Mice and hamsters were administered a single dose of 74As-DMA (40 mg As/kg body weight) orally, while a human subject ingested DMA corresponding to 0.1 mg As/kg body weight. Ion exchange chromatography, paper electrophoresis, thin layer chromatography as well as arsine generation--gas chromatography combined with atomic absorption spectrophotometry or mass spectrometry were used to characterize the arsenic metabolites in urine and feces collected over 48 hours after treatment. In mice and hamsters 3.5% and 6.4% of the dose, respectively, were excreted in urine in the form of trimethylarsine oxide (TMAO). No TMAO was found in feces. A DMA-complex was detected in urine and feces. It amounted to about 13% of the dose in mice and 15% in hamsters. About 80-85% of the dose was eliminated in urine and feces in the form of unmetabolized DMA. No demethylation of DMA to inorganic arsenic was observed. In man, about 4% of the dose was excreted in urine as TMAO and about 80% as DMA.

Biotransformation of dimethylarsinic acid in mouse, hamster and man.

The metabolism of dimethylarsinic acid (DMA), a common pesticide and the primary metabolite of inorganic arsenic in mammals, has been studied in mice and rats. About 80% of an oral dose (0.4 mg As/kg body weight) was absorbed from the gastrointestinal tract. In the mice, more than 99% of the dose was eliminated within 3 days, as compared to about 50% in the rats, mainly due to accumulation in the blood. The tissue distribution in the mice was characterized by highest initial (0.5–6 hr) concentrations in kidneys, lungs, intestinal mucosa, stomach, and testes. Tissues with longest retention time were lungs, thyroid, intestinal walls and lens. No demethylation of the74As-DMA to inorganic arsenic was observed, but some of the74As-DMA in the tissues was apparently in a complexed form.

Erminio Marafante

Papers

Metabolism of arsenobetaine in mice, rats and rabbits

Intracellular interaction and metabolic fate of arsenite and arsenate in mice and rabbits

Effects of low dietary intake of methionine, choline or proteins on the biotransformation of arsenite in the rabbit.

Biotransformation of dimethylarsinic acid in mouse, hamster and man.

Tissue distribution and retention of 74As-dimethylarsinic acid in mice and rats.