Source of Iodine-131 in the Wissahickon: Cancer Patients' Urine

Photo: Charles Fox/Philadelphia Inquirer

As a follow-up to the previous post about the detection of iodine-131 in Philadelphia-area streams in April 2011, the Philadelphia Inquirer ran an article on July 11 that identified the likely source of the contamination. Pictured above are biologists with the Philadelphia Water Department doing some detective work in the Wissahickon Creek. The article reveals the prime suspect:

"The source they now suspect was a surprise. Iodine-131 is used to treat thyroid cancer, and they suspect it's coming from patients excreting excess radioactivity in their urine, which then winds up in rivers, and ultimately in Philadelphia's drinking water intakes."

The article mentions a few of the possible culprits that were investigated, including the Limerick nuclear power plant (iodine-131 is a byproduct of nuclear fission) and even the possibility that contamination resulted from the nuclear disaster in Fukushima, Japan. In the aftermath of this story, the water department is continuing to monitor for iodine-131 and has carbon-filtration technology at its treatment plant should elevated levels again be detected.