Thursday, September 24, 2009

NIBW Update - contaminated water release on September 23, 2009

From an email from Rachel Loftin, project manager for the North Indian Bend Wash Superfund area, to the NIBW Community Involvement Group -
Dear NIBW Community Involvement Group:

I am Rachel Loftin, the new EPA Project Manager for the Indian Bend Wash site, and I'd like to share information with you regarding a release that occurred yesterday, September 23, 2009, at Well PCX-1, a groundwater extraction well that pumps water to be treated at the Miller Road Treatment Facility (MRTF).

Here's what EPA has learned from the Salt River Project:

First, and most importantly, we want you to know that the spill did not impact the drinking water supplied by the Miller Road Treatment Facility.

Between approximately 6:00 am and 7:00 am yesterday (September 23, 2009), a release from Well PCX-1 occurred. The spill lasted a little over 40 minutes. The SRP reports that a valve at Well PCX-1 failed, leading to the spill of untreated water. It appears from photographs taken immediately after the incident, as well information from witnesses of the actual spill and the visual evidence regarding the slope of the surrounding terrain, that most of the spilled water flowed away from the canal and on to Miller Road. A small portion of the spill appears to have leaked into the Arizona Canal adjacent to the well. The spill contained up to 75 ug/l (micrograms per liter) of trichloroethelyene (TCE) and the volume of water spilled is estimated to be less than 20,000 gallons.

The Arizona Canal provides water to downstream water purveyors, including the cities of Tempe, Phoenix, Glendale, and Peoria. The closest downstream plant is the City of Tempe's Johnny G. Martinez Water Treatment Plant (JGMWTP), which is roughly 5 miles downstream. The next closest downstream plant is City of Phoenix 24th Street Plant, which is roughly 7 miles downstream.

We believe, and the preliminary data indicates, these water purveyors were not impacted by the release because of their distance from the PCX-1 location, the fact that the released water became mixed with water that was already in the canal thereby reducing the concentration of TCE, and the fact that TCE tends to dissipate rapidly. SRP notified both water purveyors immediately. At EPA's request, and as a precaution, the City of Tempe's JGMWTP and the City of Phoenix 24th Street Plant sampled for TCE to be sure the water meets the safe drinking water standard for TCE which is 5 ug/l. Expedited results from water samples taken in the Arizona Canal at a location about 50 feet downstream from PCX-1 well, at Chaparral Road, and at Camelback Road indicate no detectable concentration of TCE in the canal. Preliminary sampling results taken at the City of Tempe's plant also indicate no detections of TCE. We expect to receive results from the City of Phoenix plant in a day or so.

The SRP acted very quickly to:

1. Determine what and where the problem was;
2. Stop the spill by turning off the well;
3. Obtain samples of the spilled water on Miller Road, in the canal, and downstream of the release;
4. Vacuum the spilled water along Miller Road;
5. Sample the soil on the canal bank and Miller Road; and
6. Contact appropriate parties including EPA, ADEQ, the Cities of Phoenix and Tempe water utility districts, and the City of Scottsdale where the MRTF is located.

What happens next?

•The SRP is gathering additional information and will provide it along with sampling results to EPA in the next day or so.
•The Cities of Phoenix and Tempe will also provide sampling data for the 24th Street Plant and the JGMWTP.
•The SRP will provide a report on the incident within seven days.
•I will share the sampling data and incident report with all of you when I receive them.

I look forward to planning the upcoming annual meeting with you in the short term, and meeting you all in a few weeks. In the interim, please contact me at 415/972-3253 or by e-mail if you have any questions.



My work week has started, so I won't be able to follow up on this until next week at the earliest. For more information, please contact Ms. Loftin at the above number.


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