John N. Smitha, Robin M. Brown, William J. Williams, Marie Robert, Richard Nelson, and S. Bradley Moran. Arrival of the Fukushima radioactivity plume in North American continental waters PNAS Dec 29 2014 Early Edition
The large discharge of radioactivity into the northwest Pacific Ocean from the 2011 Fukushima Dai-ichi nuclear reactor accident has generated considerable concern about the spread of this material across the ocean to North America. We report here the first systematic study to our knowledge of the transport of the Fukushima marine radioactivity signal to the eastern North Pacific. Time series measurements of 134Cs and 137Cs in seawater revealed the initial arrival of the Fukushima signal by ocean current transport at a location 1,500 km west of British Columbia, Canada, in June 2012, about 1.3 y after the accident. By June 2013, the Fukushima signal had spread onto the Canadian continental shelf, and by February 2014, it had increased to a value of 2 Bq/m3 throughout the upper 150 m of the water column, resulting in an overall doubling of the fallout background from atmospheric nuclear weapons tests. Ocean circulation model estimates that are in reasonable agreement with our measured values indicate that future total levels of 137Cs (Fukushima-derived plus fallout 137Cs) off the North American coast will likely attain maximum values in the 3–5 Bq/m3 range by 2015–2016 before declining to levels closer to the fallout background of about 1 Bq/m3 by 2021. The increase in 137Cs levels in the eastern North Pacific from Fukushima inputs will probably return eastern North Pacific concentrations to the fallout levels that prevailed during the 1980s but does not represent a threat to human health or the environment.
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Szabo J, Minamyer S. Decontamination of radiological agents from drinking water infrastructure: a literature review and summary. Environment International 2014 Nov;72:129-32. doi: 10.1016/j.envint.2014.01.020.
This report summarizes the current state of knowledge on the persistence of radiological agents on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some important radiological agents (cesium, strontium and cobalt), but important data gaps remain. Although some targeted experiments have been published on cesium, strontium and cobalt persistence on drinking water infrastructure, most of the data comes from nuclear clean-up sites. Furthermore, the studies focused on drinking water systems use non-radioactive surrogates. Non-radioactive cobalt was shown to be persistent on iron due to oxidation with free chlorine in drinking water and precipitation on the iron surface. Decontamination with acidification was an effective removal method. Strontium persistence on iron was transient in tap water, but adherence to cement-mortar has been demonstrated and should be further explored. Cesium persistence on iron water infrastructure was observed when flow was stagnant, but not with water flow present. Future research suggestions focus on expanding the available cesium, strontium and cobalt persistence data to other common infrastructure materials, specifically cement-mortar. Further exploration chelating agents and low pH treatment is recommended for future decontamination studies.
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Several thousand gallons of water containing tritium was accidentally released at Exelon Nuclear’s Limerick Generating Station last month and then discharged into the Schuylkill River. It presented no immediate public health or safety risk….but was not reported to the public until 23 days after the incident….click here for news article….
One thyroid patient receiving I-131 treatment could excrete enough of the substance to be measurable in a watershed…..but below concentrations of concern.
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This study concludes that the average cancer risks presented by I-131 intake of Tokyo citizens due to the Fukushima reactor accident are lower than the annual risks of traffic accidents, naturally occurring radioactive material (potassium 40), and environmental pollutants such as diesel exhaust particles. Even so, this will not be comforting to the affected citizens and to those opposed to nuclear power.
Murakami, M., and Oki, T. 2012. Estimation of thyroid doses and health risks resulting from the intake of radioactive iodine in foods and drinking water by the citizens of Tokyo after the Fukushima nuclear accident. Chemosphere. Mar 2.
Abstract: The release of radioactive materials from the Fukushima nuclear power plant after the Great East Japan Earthquake on 11 March 2011 poses health risks. In this study, the intake of iodine 131 (I-131) in drinking water and foods (milk, dairy products, and vegetables) by citizens of Tokyo was estimated. The effects of countermeasures (restrictions on the distribution of foods and the distribution of bottled water for infants) on reducing intake were also evaluated. The average thyroid equivalent doses without countermeasures from 21 March 2011 were 0.42mSv in adults, 1.49mSv in children, and 2.08mSv in infants. Those with countermeasures were 0.28, 0.97, and 1.14mSv respectively, reductions of 33%, 35%, and 45%. Drinking water contributed more to intake by adults and children than foods. The intake of I-131 within the first 2weeks was more than 80% of the estimated intake, owing to its short half-life, indicating that rapid countermeasures are important in reducing intake. The average risks of cancer incidence and mortality due to I-131 for infants were estimated to be 3×10(-5) and 0.2×10(-5), respectively, lower than the annual risks of traffic accidents, naturally occurring radioactive material (potassium 40), and environmental pollutants such as diesel exhaust particles.
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Tokyo tap water “unfit” for babies…..210 Bq /L….
Refrain from eating vegetables such as cabbage, the “komatsuna” leaf vegetable, broccoli and cauliflower…..
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Drinking water wells are not affected….click here for news report….
Sequoyah Nuclear Plant