Arsenic may enter water supplies through discharge of industrial wastewater and agricultural pollution, or the dissolution of natural arsenic particles in rain, snow or groundwater. Arsenic is also released into the environment through the manufacturing of pesticides and the burning of fossil fuels. It is also a by-product of copper smelting, mining and coal burning.

Rocks and soil release arsenic into the ground water which can be drawn into water wells. Sometimes natural erosion can also introduce large quantities of arsenic into a local water source.

Arsenic has been recognized as a poison since ancient times. A long-term exposure to high levels of arsenic in drinking water causes bladder, lung, skin, kidney and liver cancer. It can also harm the central and peripheral nervous systems, affect heart functions, damage bloods vessels, and can cause tremors, headaches, numbness and serious skin problems. It can also cause birth defects and reproductive problems.

Some symptoms linked to long-term exposure to high levels of arsenic in drinking water include thickening and discoloration of the skin, nausea and diarrhea, decreased production of blood cells, keratosis and peripheral vascular diseases. Acute arsenic poisoning associated with ingestion of water with high levels of arsenic includes abdominal pain, vomiting, and pain to the extremities and muscles.

Arsenic poisoning in drinking water is a global problem. As research continues to find more advanced and practical techniques of detecting contaminated water sources and remediating them, we must seek to implement updated analytical methods to avoid the hazardous consequences of arsenic poisoning.

Inorganic arsenic is documented as a human carcinogen, and some organic arsenic compounds are regarded as non-toxic to humans. It is difficult to compare the intake of arsenic from food directly with that from drinking water, as the form and biological availability in these two sources vary. It has been estimated that about 25% of the intake of arsenic from food is inorganic and 75% is organic.

Manganese dioxide-coated filters, which are commonly used for iron and manganese removal, appear capable of reducing arsenic concentration to 0.025 mg/L or less. In-house water treatment devices that are capable of reducing arsenic levels in water include reverse osmosis and water distillation.

Possible solutions for ground water users include extending the well casing into deeper ground water or drilling a new well into another aquifer. If possible, connection to a public water distribution system should be considered.

The Saskatchewan Drinking Water Quality Standards and Objectives for arsenic in drinking water has set an interim maximum acceptable concentration of 0.025 mg/L.