From Asahi Shinbun (1/30/2012):
Starting February, TEPCO will pour cement mixed with clay on the ocean floor near the water intake canals for Reactors 1 thorugh 6 at Fukushima I Nuclear Power Plant. It is to prevent radioactive cesium that exists in high concentration on the ocean floor when the company builds watertight bulkheads to prevent contaminated groundwater from the plant from leaking into the ocean.
4700 terabecquerels of radioactive cesium leaked near the water intake canal for Reactor 2, which was 20,000 times the national standard for allowed oceanic discharge per year. The survey of the ocean around the plant last November found maximum 1.6 million becquerels/kg [wet] of radioactive cesium from the ocean soil.
According to TEPCO, the cement mix will be poured over 7-hectare area, to the thickness of about 60 centimeters. TEPCO says the mix won't solidify because the cement will be mixed with clay. In building the bulkheads, steel beams will be driven into the ocean floor. The local fishermen's cooperatives have expressed concern over the dispersion of radioactive cesium deposited on the ocean floor due to the construction work.
I don't quite understand the part about the cement-clay mix not solidifying.
On a separate but related news, TEPCO has announced that it will work with the local fishermen's associations to study the effect of radioactive materials on fish by having the fishermen fish near the plant and measure radioactivity in fish.
More than 10 months have passed since the accident. (Where has the national government been?)
Also from Asahi Shinbun (1/28/2012):
On January 27, TEPCO revealed that it would conduct the monitoring survey of marine life within the 20 kilometer radius from Fukushima I Nuclear Power Plant from February till April. The survey is to study the contamination of marine life by radioactive materials.
TEPCO attended the meeting of the Fukushima Prefecture Fishermen's Cooperative Association and asked for their cooperation. The president of the association said after the meeting, "We want to know the condition of the fish in the area, so we will cooperate."
They will pick several locations that have been found with high radiation and with low radiation in the regular surveys of seawater and the ocean soil by the national and prefectural governments. The survey will be done 4 times a month, and the results will be published.
Unlike farmers in Fukushima who went ahead and decided to grow their crops as normal after the worst nuclear accident had happened near them, no matter how little information they may have had regarding the accident and resultant contamination, fishermen in Fukushima have decided not to fish, no matter how little information they may have had.
Fukushima farmers will continue to grow crops this year on their highly contaminated soil, hoping for good luck of either radioactive cesium, strontium not getting absorbed into their crops or their crops not being subject to testing while relying on the guilty feeling of the majority of consumers who believe in "Support Fukushima by eating" and on distributors who can cleverly disguise Fukushima produce as something else. As far as I know, Fukushima fishermen will continue to abstain from fishing in their ocean.