Bay Area rainwater tested last month exceeded federal standards for radiation in drinking water by 46 times, but a federal agency downplayed the potential health effects because the radiation is weakening rapidly and short-term exposure brings minimal risks.
Results released Saturday by the U.S. Environmental Protection Agency show that rainwater tested in Richmond on March 22 contained 138 picocuries per liter of iodine-131, a radioisotope that can influence thyroid activity and cause cancerous cells. According to the EPA, drinking water is only permitted to contain 3 picocuries per liter.
But iodine-131 has a “half-life” of just eight days, which means it dissipates to half its initial radioactivity within that time frame.
The new results confirm similar data from UC Berkeley’s Department of Engineering, which recently found cases in which milk, creek water, potable water and spinach and mushrooms carried traces of the radioactive isotope.
The department’s test results showed on March 24, rooftop water exceeded federal drinking water iodine-131 thresholds by 181 times, a number that has been decreasing since.
“It’s already decaying … and it’s not necessarily meaning it’s there at the level that is harmful,” supervising Professor Kai Vetter said.
Vetter said a person would have to drink 500 liters of the contaminated rainwater to ingest the level of radiation a person is exposed to on a single roundtrip flight from San Francisco to Washington D.C.
“We are continuously bombarded with toxins, and our body is able to defend itself,” he said.
But health hazards aside, another Bay Area professor has criticized the EPA’s tardy response since this is the first time in the more than three weeks since the Fukushima I Nuclear Power Plant crisis that the agency has issued any substantial data regarding the Bay Area’s safety.
“We have an emergency network that’s supposed to help us know whether to take emergency action and it’s not working,” said Daniel Hirsch, a nuclear policy lecturer at UC Santa Cruz.
EPA officials did not respond to inquiries about the speed of their response by press time. A statement on Saturday read, “It may take up to five days for results because of the number of samples being directed to the laboratory. This is to ensure the proper analysis and quality assurance measures takes place before the results are released.”