It seems that testing of rain water on the U.S. West coast was not very systematic, but the testing that was done showed elevated levels for Iodine
Radiation levels in rainwater collected in Portland, Oregon on March 25, 2011 were 86.8 pCi/L for Iodine 131 (I131), amongst the highest recorded in the US after Fukushima. Rain in Olympia had even higher levels of radioactive Iodine. The Portland result was not posted by EPA until April 4.
The maximum level of Iodine 131in rain in Olympia, WA was 125 pCi/L on March 24, which was not posted by EPA until April 4.
Highest levels in rainwater in California were collected March 22, 2011 in Richmond, CA with levels of 138 pCi/L.
The Drinking Water Standard is just 3 pCi/L (picoCuries per Liter, which is a very small measurement). Thus, people drinking undiluted rainwater n Portland would have consumed and been exposed to Iodine 131 at levels nearly 30 times the DWS, and 41 times the standard in Olympia. There are no results for Seattle or Bellingham areas. The DWS is set at a level based on drinking 2L/day resulting in a 4 mrem per year dose, which is a 1 in 10,000 lifetime risk of fatal cancer in adults, if consumed daily over 30 years. Children are 3 to 10 times more susceptible to develop cancer from the same does, especially because Iodine concentrates in young thyroids. Of course, Iodine 131 may cause non-cancerous health conditions.
