By Tony Davis | Arizona Daily Star
Tucson Water recently shut down a treatment plant after discovering it was sending water contaminated with chemical compounds to thousands of residents of downtown and the city’s west and north sides.
Shortly after making that discovery, utility officials also learned that they had mistakenly thought for some time that uncontaminated water was coming out of the plant, which has long treated south-side water pollution.
The utility had been sampling the water at a point its officials thought was connected to the south-side treatment plant, but which actually was getting water from other sources, administrators said last week.
It turned out that water coming out of the treatment plant was now tainted with what’s known as perfluorinated chemicals, also known as PFAS compounds. The treatment plant had been built and later upgraded to treat two other pollutants — the solvent trichloroethylene (TCE) and 1,4-dioxane — but not to treat PFAS.