Arsenic leeches into drinking water by means of erosion of natural deposits; run-off from mining, orchards, and industrial activity such as glass and electronics production wastes.
When consumed through drinking water, arsenic causes a variety of health impacts. Illness may take years to detect and severity increases over time of exposure. Health impacts include skin damage or lesions, and problems with circulatory system, immune system, increased risk of heart disease, stroke, and diabetes. It has also been associated with cancer, developmental defects, and neurotoxicity.
There is no remedial action for chronic arsenic poisoning to date. Socio-economic factors such as poverty and malnutrition contribute to the increased risk of chronic toxicity. Only prevention and early intervention can provide relief to an affected population.
Arsenic can cause short-term and long-term impacts on individual or communities of plants and animals as well as the balance of ecosystems. The severity of impacts depends on the species and time of exposure. For aquatic species, for example, effects can be evident at arsenic concentrations from a few micrograms to milligrams per liter.
Typically, the County Department of Environmental Health conducts regular testing of municipal and small drinking water systems. They test for a variety of contaminants that affect public health, including arsenic. If arsenic is detected, the agency issues a citation that the water is no longer potable, and a new drinking water source must be found, or a filtration system put in place.
The national drinking water standard for arsenic is 10 micrograms per liter. Arsenic levels exceeding this standard is a serious health risk.
When arsenic is detected in drinking water remediate action depends on the size of the drinking water system. For larger municipal water systems, managers may find the source of arsenic leeching and repair the piping. If arsenic contamination is widespread, a municipal filtration system must be installed. For smaller drinking water systems (50 connections or less), the community may have to drill a new well, or install a small-system or individual filtration systems. All remediation is costly and municipalities, policy-makers, and entrepreneurs alike are looking for low-cost, efficient solutions.