Your statement on rain water safety

Thanks to the nuclear engineering department for running this detailed study and releasing the data to the public. I have a question about your statement at http://www.nuc.berkeley.edu/RainWaterSampling

You say that one would have to drink 632 liters of undiluted rainwater to accrue the equivalent dose of radiation as from cosmic radiation, etc, in a cross country flight.

However you also write that you measured an Iodine-131 concentration corresponding to 4.26 Bq/l. In their public statement about Iodine at http://www.epa.gov/superfund/health/contaminants/radiation/pdfs/iodine.pdf the EPA recommends to limit the intake to 3 picuries/l=0.11 Bq/l. Your measured concentration is 40 (fourty) times higher than this number. How do you explain this discrepancy?

And on the relevance of this question, as no one is obviously drinking rain water: would you expect that the reservoirs that keep the bay area's rain water contain less than 2.5% rain water after the rainfalls of the last week?

Again thanks for your work! And thanks in advance for clarifying!