In the past, testing for arsenic in drinking water has been as difficult as removing it. A variety of test kits have appeared on the market deriving from the need for easier, cheaper and faster methods. These test kits rival both the accuracy and low detection ability of laboratory instrumentation.
Arsenic often is remembered as a poison, used since medieval times to eliminate unsuspecting persons. In those days, arsenic was a perfect murder weapon because the symptoms of death mimicked other causes and, therefore, were hard to trace. Severe poisoning and possibly death can occur from just 100 mg of arsenic. Lower frequent doses like those received from contaminated drinking water build up in the body and produce varying side effects. Cancer, diabetes and cardiovascular problems are linked to arsenic poisoning. Some research suggests that as little as 3 parts per billion (ppb) is potentially harmful.
The thought of arsenic being present at any quantity in drinking water is quite alarming to the average consumer. Groundwater contaminated with arsenic has been found in 49 of the 50 states in the United States. Arsenic most often is present in the environment in the form of inorganic arsenic and enters groundwater from the erosion of arsenic-containing rocks and soil. Inorganic arsenic consists of arsenic ions combined with chlorine, oxygen and sulfur ions to form compounds known as arsenite (As+3) and arsenate (As+5). (Arsenite is the more toxic of the two forms.)