Majia here: Radioactive water from Fukushima has contaminated the ocean in an ongoing fashion for the last two years.
In an interview in October 2012, titled ‘Fishing for Answers off Fukushima,’ Ken Buesseler of Woods Hole noted that ‘the nuclear power plants continue to leak radioactive contamination into the ocean’:
K. Buesseler (26 October 2012) ‘Fishing for Answers off Fukushima’, Science Magazine, 338, 480-482.
Majia here: Buesseler has expressed concerns about the state of the site given the amounts of water being used to cool the reactors and the difficulties of capturing, filtering, and storing contaminated water. In an essay for CNN in March 2012 titled, ‘What Fukushima Did to the Ocean’ describes his concerns about site saturation and ocean contamination:
K. Buesseler (11 March 2012) ‘What Fukushima Accident Did to the Ocean’, CNN, http://www.cnn.com/2012/03/10/opinion/buesseler-fukushima-ocean/index.html
Majia here: It is very likely with Tepco’s storage problems that even greater volumes of highly radioactive water will now enter the ocean:
Tsuyoshi Inajima (2013, April 11) Tepco Faces Decision to Dump Radioactive Water in Pacific Ocean http://www.bloomberg.com/news/2013-04-11/tepco-faces-decision-to-dump-radioactive-water-in-pacific-ocean.html
Majia Here: With two years of ongoing contamination, it seems likely that the ocean is now SIGNIFICANTLY MORE CONTAMINATED than it was in June of 2011 when data for this study were collected:
Biogeosciences Discuss., 10, 6377-6416, 2013:10.5194/bgd-10-6377-2013
Cesium, iodine and tritium in NW Pacific waters – a comparison of the Fukushima impact with global fallout
P. P. Povinec1, M. Aoyama2, D. Biddulph3, R. Breier1, K. Buesseler4, C. C. Chang3,5, R. Golser6, X. L. Hou7, M. Ješkovský1, A. J. T. Jull3,5,8, J. Kaizer1, M. Nakano9, H. Nies10, L. Palcsu8, L. Papp8, M. K. Pham10, P. Steier6, and L. Y. Zhang7
Abstract. Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons.
Surface and water column seawater samples collected during the international expedition in June 2011 were analyzed for 134Cs, 137Cs, 129I and 3H. The 137Cs,129I and 3H levels in surface seawater offshore Fukushima varied between 0.002–3.5 Bq L−1, 0.01–0.8 μ Bq L−1, and 0.05–0.15 Bq L−1, respectively.
At the sampling site about 40 km from the coast, where all three radionuclides were analyzed, the Fukushima impact on the levels of these three radionuclides represent an increase above the global fallout background by factors of about 1000, 30 and 3, respectively. The water column data indicate that the transport of Fukushima-derived radionuclides downward to the depth of 300 m has already occurred. The observed 137Cs levels in surface waters and in the water column are in reasonable agreement with predictions obtained from the Ocean General Circulation Model, which indicates that the radionuclides have been transported from the Fukushima coast eastward.
The 137Cs inventory in the water column (the area from 34 to 37° N, and from 142 to 147° E) due to the Fukushima accident is estimated to be about 2.2 PBq.
The amount of 129I and 3H released and deposited on the NW Pacific Ocean after the Fukushima accident was estimated to be about 7 GBq and 0.1 PBq, respectively.
Due to a suitable residence time in the ocean, Fukushima-derived radionuclides will provide useful tracers for isotope oceanography studies on the transport of water masses in the NW Pacific Ocean.
The researchers note [excerpted page 6393]: "measured 137Cs concentrations in surface waters ranged from 1.8mBq L−1 to 3500mBq L−1, up to 3500 times higher than the global fallout background, although the cruise track did not go closer than 30 km from the coast.."
The elevated 137Cs levels covered an area of around 150 000 km2 (south of 38°N and west of 147° E). Even 25 at distances around 600 km off Fukushima, 137Cs activity concentrations of around 0.3 Bq L−1 were found, i.e. by about a factor of 300 above the global fallout background of 1mBq L−1.
Hat tip Phillip Up North for pointing this out here
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