Emerging Contaminant in Source Water from Medical Treatment: Iodine 131 (Poster)

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With releases of radiation from the Fukushima Dai-ichi Nuclear Power Plant in Japan, the US Environmental Protection Agency (EPA) and its partners increased its monitoring of drinking waters, air and other potential radionuclide exposure routes and a review of EPA’s historical RadNet database.  During this enhanced monitoring, elevated 131I concentrations were detected in surface waters used as source waters for two of the Philadelphia Water Department’s (PWD) drinking water plants.  Review of RadNet data identified episodes of detectable 131I in finished drinking water at the PWD’s three drinking water treatment plants since the late 1990s.  The PWD, the Pennsylvania Department of Environmental Protection (PADEP) and the US EPA initiated a robust monitoring program to determine the source of the 131I and to develop a better characterization of the levels and variability of source water 131I.   It was discovered that the source of the 131I probably came from excretion from thyroid cancer patients into two source waters. Besides monitoring, PWD partnered with the Philadelphia PSR to conduct research and in-person interviews of radiology staff of local hospitals and advocacy group to understand the medical uses of 131I and provide guidance to the PWD.  Although PWD did not exceeded the maximum contaminant level (MCL) for drinking water distributed to customers (the finished water is regulated, not the source water), no action has been required but a potential emerging contaminant has been identified and several new ideas have been generated to addressing this issue among health professionals.