Scientific Reports (Nature.com), Mar. 4 2014: The total amount of decay-corrected 134Cs in the [subtropical] mode water was an estimated about 6 PBq [petabecquerels, i.e. 6 quadrillion becquerels] corresponding to 10–60% of the total inventory of Fukushima-derived 134Cs in the North Pacific Ocean. […] The decay corrected ratio of 134Cs/137Cs in soils has been calculated to be 1.0, which suggests that the total amounts of 134Cs and 137Cs released from FNPP1 were equivalent. […] the total amount of Fukushima-derived radiocesium in the North Pacific remains uncertain, because it has been difficult to obtain sufficient samples of water, especially from subsurface and deep waters, in the vast North Pacific Ocean […] Estimates of the total 134Cs released to the North Pacific Ocean ranged from 10 PBq (direct discharge of 4 PBq + atmospheric deposition 6 PBq) to 46 PBq (16 + 30 PBq). Thus, the 6 PBq inventory accounts for 10–60% of the total release. However, the total inventory in the subtropical region derived from the activity in STMW [Subtropical Mode Water] may be underestimated, because CMW probably carried the radiocesium into the subtropical region, too […] The estimated inventory in the subtropical region (6 PBq or 10– 60% of the total inventory) is probably a lower limit of estimation because contribution of CMW [Central Mode Water] was not counted. [...]
Funding: “This work was partially supported by a Grant-in-Aid… from the Ministry of Education, Culture, Sports, Science and Technology of Japan”
Note: The study states that up to 46 PBq of 134Cs is estimated to have been released into the North Pacific Ocean from Fukushima Daiichi. Yet, it also states that the 6 PBq in the study area represents between 10-60% of the total 134Cs released into the North Pacific Ocean. If the 10% figure is used, the total release into the N. Pacific would equal 60 PBq of 134Cs. The study also states the releases of 134Cs and 137Cs were equivalent, resulting in a total of 120 PBq into the N. Pacific. This total does not include releases deposited on land or in other bodies of water.
Chernobyl Comparison: A report by the Nuclear Enrgy Agency states that when more detailed deposition data eventually became available, the United Nations estimated the total Chernobyl release of 137Cs at 70 PBq. 134Cs is estimated to have been 53.7% of the 137Cs — approximately 38 PBq of 134Cs — resulting in a total of 108 PBq. Unlike the Fukushima total reported above, this does include all 134Cs and 137Cs releases from Chernobyl — not just what was deposited in the ocean.
And: Marine Chemist in Jan. 2014: Latest numbers I have are Fukushima has released 80 Quadrillion Bq of cesium-137 (Chernobyl estimated at 70 Quadrillion) -- "The radioactive plume itself has actually arrived... it’s already here" on west coast of N. America (AUDIO)
Published: June 30th, 2014 at 2:10 pm ET
- Gov’t report reveals Fukushima radioactive release much larger than Chernobyl — Japan reactors could have emitted nearly four times as much cesium-137 October 20, 2014
- Russian Study: Fukushima released 100 quadrillion becquerels of cesium into atmosphere… In just ONE day — About equal to Chernobyl’s total release August 29, 2013
- EU-funded Research: Fukushima atmospheric release of 210 quadrillion becquerels of cesium-137 used as upper bound in simulation — Chernobyl estimated at 70 to 85 quadrillion September 23, 2013
- Highest Estimate Yet: Fukushima about equal to Chernobyl, says US gov’t funded study April 3, 2012
- Gov’t Report: Fukushima released up to 181 Quadrillion Bq of cesium, Chernobyl was 105 Quadrillion — Radioactive material to flow from Japan “for years to come” — Fukushima radionuclides have now spread “throughout N. Pacific” May 20, 2014