What is arsenic?

Arsenic is a naturally occurring substance in groundwater. Arsenic can occur both naturally (organic arsenic) or as a byproduct of business and industry (inorganic arsenic). Organic arsenic can be found in water, air, soil, volcanic rock, plants and animals. The inorganic form of arsenic is used to preserve wood; create, mine or treat metals; and is also added to some paints, dyes and soaps. Arsenic is known to cause health problems.

There is a new Federal Environmental Protection Agency (EPA) standard for arsenic, a naturally occurring substance in groundwater. The EPA recently tightened the maximum contaminant level standard from 50 parts per billion (ppb) to only 10 ppb.

What are some of the specific concerns about arsenic?

Arsenic is especially prevalent in the Western states and makes its way into the water supply as water percolates down through rock and soil. When groundwater is the primary source of water for a community - as is the case for many small water companies in rural areas - complying with the lower standard will require new, and sometimes costly, treatment methods.

The EPA estimates that approximately 13 million Americans are served by water systems that do not comply with the reduced standard.  The Arizona Department of Environmental Quality (ADEQ) estimates that nearly one third of Arizona's water systems subject to the regulation do not meet the new, tighter standard. ADEQ regulates water quality for all water companies in Arizona.

The Arizona Corporation Commission has other regulatory and ratemaking authority for some of the water companies overseen by ADEQ. The Commission requires companies to be in compliance with ADEQ standards.

It is important to note that the arsenic standard was initiated by the EPA and will be enforced by ADEQ. The Commission will be involved only to the extent that the water companies it regulates will be required to comply. Some of these companies may come to the Commission to seek approval for rate adjustments, depending upon the costs they incur to comply with the tighter standard.

What are some of the health issues associated with arsenic?

Information provided by the EPA states that the new rule addresses the long-term, chronic effects of exposure to low concentrations of arsenic in drinking water. A fact sheet on the EPA website states that studies have shown that the ingestion of arsenic can cause adverse health effects, including:

Cancerous Effects: skin, bladder, lung, kidney, nasal passages, liver and prostate cancer; and Non-cancerous effects: cardiovascular, pulmonary, immunological, neurological and endocrine (e.g., diabetes) effects. Source: www.epa.gov/dwreginfo/arsenic-and-your-distribution-system

How can I learn more?

For more information from the EPA, go to the safe drinking water section of the EPA's internet site: www.epa.gov/safewater. You may also contact Arizona's Department of Environmental Quality. For wastewater issues call 602-771-4479, for drinking water issues call 602-771-6403, or visit their website at www.azdeq.gov/programs/wqd.