Fukushima Marine Environment Monitoring - 5 May 2011
Fukushima Marine Environment Monitoring - 5 May 2011
IAEA Environment Laboratories, Monaco
H. Nies, M. Betti, I. Osvath, E. Bosc
3.Marine discharges due to leaking cable pit at Unit 2
In a news release issued on 25 April, NISA has communicated their evaluation of a report submitted by TEPCO on April 21 in relation to water containing radionuclides with high activity that flowed out from Unit 2 of Fukushima Daiichi Nuclear Power Station.
The outflow rate is estimated to have been approximately 4.3 m³/h.
Concentration values, estimated from measurements, are:
I-131: 5.4 GBq/L
Cs-134: 1.8 GBq/L
Cs-137: 1.8 GBq/L
leading to an estimated overall amount of total release of about 4.7 PBq(4.7 x 1015Bq)
H. Nies, M. Betti, I. Osvath, E. Bosc
11.Monitoring of marine food
Sampling locations of marine fish products as of 30 April (issued by the Japanese Ministry of Agriculture, Forestry and Fisheries)
In Ibarakiprefecture, three samples of seafood (sand lance) from
28 April: one sample
29 April: two samples
were above the regulation values set by the Japanese authorities for Cs-134/Cs-137
Sand lances are so far the only fish species, which showed levels above the recommended limits.
26.Conclusions on the impact to the marine environment in the Pacific
The highest levels are still measured close to the Nuclear Power Stations Fukushima, namely at the screen of Unit 2, 30 m, 330 m and 10 km near-shore even though with a decreasing trend.
Concentration data from about 30 km off-shore show a generally decreasing temporal trend and partly, the concentrations are below the limit of detection at the applied methods.
It can be expected that, if no additional releases occur, the levels measured at the stations 30 km off-shore will continue to decrease significantly by dilution into deeper layers and dispersion by ocean currents
6 May 2011
H. Nies, M. Betti, I. Osvath, E. Bosc
27.Conclusions
It can be expected that the traces from the discharge and deposition to the marine environment from Fukushima NPPs will be taken up by the Kuroshio current system in the north Pacific
It will be possible to follow these traces – mainly Cs-137 and Cs-134 - over the next few years in the northern Pacific
Water with such traces will reach the Canadian and US Coast probably in one to two years’ time
6 May 2011
H. Nies, M. Betti, I. Osvath, E. Bosc
