Scottsdale: TCE scare limited to private supply

Drinking water delivered to nearly 5,000 Arizona American Water Co. customers in Scottsdale and Paradise Valley last month fell within federal guidelines for trichloroethylene, a suspected cancer-causing chemical, company officials said Friday.

Water scare outrages Scottsdale residents

That reassurance comes a day after federal health officials announced at a public meeting that there were high concentrations of TCE at the company’s treatment plant at Miller Road and McDonald Drive.

Arizona American Water spokesman Todd Walker said the company has a total of 4,750 customers in the Paradise Valley Water District, with 1,200 in Scottsdale and the balance in neighboring Paradise Valley.

More than 26 percent of the water the private utility provides the district is pumped and treated from the North Indian Bend Wash Superfund site in Scottsdale, where groundwater is contaminated with TCE.

The incident has prompted Rep. Harry Mitchell, D-Ariz., to request a meeting with Stephen Johnson, chief of the U.S. Environmental Protection Agency, to discuss why a month passed before the public was notified of excessive TCE concentrations found in treated water at the Arizona American Water Co. treatment plant.

“The disclosure raises questions, not only about the emission, but about why the public was not informed about it until weeks after the event,” Mitchell wrote. “Notice of the exposure is inadequate and unacceptable.”

Meanwhile, Scottsdale officials said that although the city blends 10 million gallons a day of treated water pumped from the Superfund site into the municipal water supply, tainted water was limited to Arizona American Water Co.’s system.

City officials take weekly samples at the Central Groundwater Treatment Facility — at the intersection of Pima and Thomas roads — of water entering the plant, water leaving the plant bound for a storage tank, and just prior to releasing it into the municipal water supply, according to Scottsdale Water Resources Department officials.

EPA officials on Thursday announced that water containing 9.2 parts per billion of TCE had been introduced into American Water’s drinking water supply. The federal maximum for TCE in drinking water is 5 parts per billion. American Water officials said that the tainted water was blended with TCE-free water, lowering TCE concentrations to within federal mandates.

The incident happened at the Miller Road Treatment Facility, 5975 N. Miller Road, which is owned and operated by American Water. The facility has three treatment towers, two of which are normally in use.

On Oct. 15, workers at the site shut down one of the towers for inspection and shifted operations to the third, unused tower. Samples were taken of the water leaving the new tower and sent to a lab. The third tower was in use for eight days.

The EPA did not receive the results from tests on the water, however, until Wednesday because the first lab had equipment problems, requiring that the sample be sent to a second lab, EPA officials have said.

But Mitchell stated that a month is far too long to wait, and that EPA officials only made the announcement Wednesday as a “postscript” in a public meeting about the Superfund site “after several decidedly less important matters had been discussed.” The agenda for the meeting — to which many residents had come to hear about Motorola’s request to remove air scrubbers at another Superfund site — included no mention of the possible TCE exposure.

“I hope this does not reflect the priority EPA assigns to potential exposure to TCE,” Mitchell wrote.

The EPA is investigating how the water may have remained tainted. The Indian Bend Wash Superfund site, one of the largest groundwater cleanup projects in the United States, covers a 13-square-mile area in Scottsdale and Tempe. About three-quarters of the Indian Bend Wash contamination is in Scottsdale, covering an area from McDonald Drive to McKellips Road, between Pima Road and 68th Street.