small spike in Massachusetts
So... the highest concentration of 131-I was 23 picocuries per liter, or 0.6% of the amount of radiation found in a typical banana, which clocks in at 3520 picocuries per kg (CRC Handbook on Radiation Measurement and Protection, Vol 1 p. 620 Table A.3.7.12, CRC Press, 1978). Plus, with a half life of 8 days, it’s not like that 131-I is staying around.
I used to buy 1 milli-curie of 35-S at a time, and use about 1-2 micro-curies at a time. If the small amount of radiatioactive iodine in those rain samples is enough to kill, then I’m amazed that I didn’t fall over dead the first time I used 35-S! Shielding isn’t even required to work with 35-S.
That report trying to link the Fukushima plant with higher infant death rates is just plain irresponsible.