Fountain Hills residents recently received their annual (2019) Water Quality Report from EPCOR Water and some made note of a level of arsenic in the water that exceeded EPA standards. It is the highest level arsenic tested for in Fountain Hills in recent years.

EPCOR reported a maximum arsenic detection of 13 parts per billion compared to a maximum compliance level (MCL) of 10 parts per billion. Ten parts per billion means there would be 10 molecules of arsenic for every 999,999,990 molecules of water, which according to the EPA is roughly equal to a few drops of ink in an Olympic sized swimming pool.

John Calkins with EPCOR’s environmental quality department said the situation that caused the one-time spike in a single test for arsenic has been corrected and recent testing shows the water quality in compliance with the EPA standard.

EPCOR has three sources of water for Fountain Hills including surface water from the Central Arizona Project (CAP) canal and two groundwater wells, according to Calkins. The two wells are located on Palisades Boulevard next to Fire Station #1 and the other is on the Desert Canyon Golf course off Saguaro Boulevard at Kingstree Boulevard.

Arsenic is a naturally occurring substance and turns up in water supplies due to natural erosion. Calkins said all three of the Fountain Hills water sources have varying amounts of arsenic. He said EPCOR uses a “blending” process to address the arsenic levels to keep it in compliance. This essentially dilutes the water to reduce the parts per billion. Calkins said a situation occurred where water with a higher level of arsenic was pulled from one of the wells while the blending system was shut down. This resulted in the unusual spike. The blending system has now been hard wired so water from a single source cannot be brought into the system independently without mixing, according to Calkins.

The well on Palisades Blvd. is also equipped with a special “media” inserted into the system which attracts the arsenic to prevent it from circulating into the system. Calkins said it is fair to compare that media for attracting the arsenic to an anode rod placed in water heaters to attract corrosive material and extend the life of the heater.

The EPA actually has a Maximum Contaminant Level Goal (MCLG) for arsenic of 0. However, recognizing that it is nearly impossible for current technology to remove all arsenic from the water the MCL of 10 ppb has been set. In recent years that has been reduced from 50 ppb.

Calkins said the EPA has defined the standard in such a way that is would be near impossible for anyone to experience the effects of arsenic in the water. He said for the 10 ppb to impact a person’s health they would need to drink two liters of the water each day for 70 years, and at that point there would be only a 10 percent chance of health risk.

Arsenic is not an “acute” health risk to the water supply compared to some bacterial contaminates as e-coli, according to Calkins.