Philadelphia Water Department Iodine-131 Q&A

In response to public concern about Iodine-131 detected in Philadelphia-area streams, PWD posted an Iodine-131 Q&A fact sheet in June. It provides a pretty good overview of the chemical and suggests that its presence in local streams and rivers isn't as much a cause for concern as some news outlets reported. The half-life is only 8 days, for example. More from the fact sheet:

"An infant would have to drink almost 600 liters of water at 2.2 pCi/L (April RadNet level), to receive a radiation dose equivalent to a one day’s worth of the natural background radiation exposure that we experience continuously from natural sources of radioactivity in our environment."

There was also some pretty interesting follow-up news on this story—some detective work was done to determine the source of the Iodine-131. We'll post more on that investigation soon.