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. 2011;6(9):e24330.
doi: 10.1371/journal.pone.0024330. Epub 2011 Sep 21.

Observations of fallout from the Fukushima reactor accident in San Francisco Bay area rainwater

Eric B Norman  1 , Christopher T Angell, Perry A Chodash
Affiliations

Observations of fallout from the Fukushima reactor accident in San Francisco Bay area rainwater

Eric B Norman et al. PLoS One. 2011.

Abstract

We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products--(131,132)I, (132)Te, and (134,137)Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Gamma-ray spectra observed from rainwater and from tap water.
(a) a portion of the gamma-ray spectrum observed from counting 1 liter of rainwater collected in Oakland on March 18, 2011. Fission-product gamma rays are indentified by their energies in keV and by their beta-decay precursor. (b) the same region of the spectrum collected from counting a 1-liter sample of Berkeley tap water. Both spectra represent the same counting period of 24 hours. Note that the gamma-ray peaks seen in the bottom spectrum do not originate in the tap water but are part of the natural background present in our laboratory environment.
Figure 2
Figure 2. Activity concentrations of 131,132I, 132Te, and 134,137Cs in Bq L−1 measured in San Francisco Bay area rain water as a function of time.
See this image and copyright information in PMC

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