Arsenic poisoning is a medical condition that occurs due to elevated levels of arsenic in the body. If arsenic poisoning occurs over a brief period of time, symptoms may include vomiting, abdominal pain, encephalopathy, and watery diarrhea that contains blood. Long-term exposure can result in thickening of the skin, darker skin, abdominal pain, diarrhea, heart disease, numbness, and cancer.The most common reason for long-term exposure is contaminated drinking water. Groundwater most often becomes contaminated naturally; however, contamination may also occur from mining or agriculture. It may also be found in the soil and air. Recommended levels in water are less than 10–50 µg/L (10–50 parts per billion). Other routes of exposure include toxic waste sites and traditional medicines. Most cases of poisoning are accidental. Arsenic acts by changing the functioning of around 200 enzymes. Diagnosis is by testing the urine, blood, or hair.Prevention is by using water that does not contain high levels of arsenic. This may be achieved by the use of special filters or using rainwater. There is not good evidence to support specific treatments for long-term poisoning. For acute poisonings treating dehydration is important. Dimercaptosuccinic acid or dimercaptopropane sulfonate may be used while dimercaprol (BAL) is not recommended. Hemodialysis may also be used.Through drinking water, more than 200 million people globally are exposed to higher-than-safe levels of arsenic. The areas most affected are Bangladesh and West Bengal. Exposure is also more common in people of low income and minorities. Acute poisoning is uncommon.
Arsenic in hot geothermal fluids was shown to be derived mainly from leaching of host rocks at Yellowstone National Park, in Wyoming, US, rather than from magmas.In the western US, there are As (arsenic) inputs to groundwater and surface water from geothermal fluids in and near Yellowstone National Park, and in other western mineralized areas. Groundwater associated with volcanics in California contain As at concentrations ranging up to 48,000 μg/L, with As-bearing sulfide minerals as the main source. Geothermal waters on Dominica in the Lesser Antilles also contain concentrations of As >50 μg/L.In general, because arsenic is an incompatible element, it accumulates in differentiated magmas, and in other western mineralized areas. Weathering of pegmatite veins in Connecticut, US, was thought to contribute As to groundwater.In Pennsylvania, As concentrations in water discharging from abandoned anthracite mines ranged from <0.03 to 15 μg/L and from abandoned bituminous mines, from 0.10 to 64 μg/L, with 10% of samples exceeding the United States Environmental Protection Agency MLC of 10 μg/L.In Wisconsin, As concentrations of water in sandstone and dolomite aquifers were as high as 100 μg/L. Oxidation of pyrite hosted by these formations was the likely source of the As.In the Piedmont of Pennsylvania and New Jersey, groundwater in Mesozoic age aquifers contains elevated levels of As—domestic well waters from Pennsylvania contained up to 65 μg/L, whereas in New Jersey the highest concentration measured recently was 215 μg/L. Food
In the United States, Schoof et al. estimated an average adult intake of 3.2 μg/day, with a range of 1–20 μg/day.