May 5, 2004
Mary Jo Pitzl
The Arizona Republic

From the Colorado River to a north Phoenix explosives firm, perchlorate has been seeping into Arizona's water supply.

Now it has flowed to the attention of state officials, who on Tuesday announced a task force to track the amount of the contaminant in Arizona's water supplies. The effort by four state agencies could create the state's first-ever standard for perchlorate, a component of rocket fuel that has been shown to inhibit the function of the thyroid gland.

Steve Owens, director of the Arizona Department of Environmental Quality, said perchlorate is on the rise as a water contaminant. Owners of the former UPCO plant in March reported perchlorate in groundwater wells at the north Phoenix facility. Tests found levels ranging from 43 to 130 parts per billion in wells southeast of the plant, which manufactures ejector seats and uses rocket propellant.

The state has set 14 ppb as the health-based guidance level, but has no standard. It's possible the task force could recommend a standard, Owens said, although it's too early to predict.

California environmental officials this spring proposed a 6 ppb standard, and the U.S. Environmental Protection Agency is studying whether to establish a nationwide level.

But Owens said there's no need to wait for EPA action.

In addition to the UPCO readings, Phoenix reported perchlorate levels of 5 ppb in two samples drawn from the Union Hills Water Treatment Plant in 2002. That water comes from the Colorado River, another source of high perchlorate levels, due to wastewater from an explosives plant up the river in Las Vegas. Tests in 2003 found undetectable levels, city officials say.

An environmental group last year reported the chemical had worked its way into Yuma-area lettuce irrigated with Colorado River water. And the group American Rivers last month put the Colorado River atop its list of the nation's most endangered rivers, reinforcing the need to get a better understanding of perchlorate contamination in Arizona, Owens said.

http://www.azcentral.com/news/articles/0505perchlorate05.html