Radiation testing in fish samples. (Photo: YouTube/NTDTV)
Govt must release more data on radiation in seafood: oceanographic group
Wednesday, July 27, 2011, 03:50 (GMT + 9)
The Oceanographic Society of Japan said the government must disclose more results from ocean radiation tests to correctly gauge the contamination levels of seafood.
Moreover, the group said the government ought to release radiation readings in sea water even if they fall below its minimum measurement level, because such low quantities may still be harmful when concentrated in seafood.
“Depending on the species, fish have been known to accumulate as much as 100 times the amount of pollutants in the environment,” explained Jota Kanda, a professor at Tokyo University of Marine Science and Technology specializing in marine environment.
A report by the Ministry of Health, Labour and Welfare reported that seafood testing off Fukushima’s coast found 68 cases of fish and marine life with radiation levels surpassing the government’s safety limit.
Fukushima prefecture tested 505 seafood items and detected excessive radiation levels in 15 samples of sweetfish, seven of salmon, seven of greenling and six of sand lance. Ibaraki prefecture found five cases of extreme radiation levels out of 265 samples, Bloomberg reports.
"The increase could be from seawater churned by swells from the recent typhoon, but it's possible that contaminated groundwater leaked from the plant," said Tetsuo Ito, head of the Atomic Energy Research Institute at Kinki University, Today Online reports.
Meanwhile, 15 other prefectures found no cases of contamination, the report reads.
At the same time, the concentrated release of radioactive material poured into Fukushima’s coast is “unprecedented,” Kanda said.
“The scope of testing needs to increase, especially in the neighbouring prefectures of Miyagi and Iwate,” Kanda said. “In Chernobyl’s case, it took about six months to a year for cesium concentrations in fish to peak.”
As Japan lacks a centralized system to check for radiation contamination of food, prefectural authorities and farmers run voluntary tests. Products including fish as far as 360 km from Dai-Ichi have been found to contain cesium and iodine.
Near the Fukushima plant’s No 3 reactor, cesium-134 levels in seawater jumped to 30 times the allowed safety standards last week, according to the Tokyo Electric Power Co (TEPCO).
“The concern is that the contaminants will travel up the food chain reaching greater concentration in higher animals,” expounded Eiji Tanaka, a professor at Tokyo University specializing in marine bioresources. “The pollutants may spread to bluefin tuna and minke whales.”
Sea water testing farther off the coast of Fukushima, Miyagi and Ibaraki prefectures found no traces of radioactive elements, according to Japan’s Ministry of Education, Culture, Sports, Science and Technology.
The minimum detection limit is defined as 4 bq per liter for Iodine-131, 6 bq/l for Cesium-134 and 9 bq/l for Cesium-137, the Ministry's report said.
“Which means that at 5 bq per l the ministry will proclaim the water safe, but concentration in fish may exceed the 500 bq limit” per kg set by the government, Kanda noted.
- More rough seas ahead for Japanese fishers
- Radioactive caesium found in whales
By Natalia Real