A particular species of small fish called sand lances caught in waters off Fukushima and Ibaraki prefectures have been found to be contaminated with radiation.

The fish, caught off Iwaki City, south of Fukushima Daiichi, were found to have concentrations of 12 500 Bq/kg of radioactive caesium, 25 times the regulated legal limit. They also had 12 000 Bq/kg of radioactive iodine, six times the legal limit, according to a report from Japan newswire NHK republished by Japan Atomic Industrial Forum. Radiation greater than legal limits was first detected in sand lances on 7 April. Sand lances are not currently being caught commercially off Fukushima or Ibaraki prefectures.

The Japanese government has carried out a simulation of the spread of radiative material in the Pacific ocean, based on surveys and data relating to ocean currents. In the short term, the material will spread out from the coast to the northeast. In the long term, the material will be picked up by a southerly current 100 km offshore in lower concentrations, and then move eastward in a rapidly-moving current off of Ibaraki prefecture, in about a month. The ministry said that the concentration of radioactive material will decrease gradually, according to a report from NHK.

A small proportion of the shiitake mushroom crop grown outdoors in eastern Fukushima have been banned from sale because of radiation contamination. The ban applies to mushrooms from 16 cities, towns and villages in the region, chief cabinet secretary Yukio Edano said, which amounts to 2.3% of the 3000 tons of mushrooms grown in the area by 660 producers in Japan’s eighth-largest producer. Mushrooms grown indoors are not affected.

Also, 11 kinds of vegetables grown in Fukushima prefecture were found to have radiation contamination on Monday 11 April. For example, Japanese parsley called seri grown in Soma City was found to contain 1960 Bq/kg, four times the legal limit.

TEPCO plans to install the last four of seven steel shutters in front of the unit 2 water intake. It has also installed silt fences in front of the water intakes of units 1 and 2 to try to prevent the spread of radioactive material from the site.

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