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Fukushima radiation cleanup might cause environmental damage

Ten months after the nuclear disaster, trust in the authorities is nearly non-existent. Without it, Japan’s government risks the biggest cleanup fiasco of all: a decontamination effort that carries huge financial and environmental costs but still fails to convince Fukushima residents that their homes, farms, and forests are safe once again. 

Fukushima nuclear cleanup could create its own environmental disaster
Decontaminating the Fukushima region to remove radioactive particles will not be possible without removing large amounts of soil, leaves and plants Winifred Bird for Yale Environment 360, part of the Guardian Environment Network guardian.co.uk,  9 January 2012  Following the nuclear disaster at Chernobyl 25 years ago, the Soviet government chose long-term evacuation over extensive decontamination; as a result, the plants and animals near Chernobyl inhabit an environment that is both largely devoid of humans and severely contaminated by radioactive fallout.

The meltdown last March of three nuclear reactors at the Fukushima Daiichi nuclear power plant in Japan also contaminated large areas of farmland and forests, albeit not as severely or extensively as at Chernobyl. But lacking land for resettlement and facing public outrage over the accident, the Japanese government has chosen a very different path, embarking on a decontamination effort of unprecedented scale.

Beginning this month, at least 1,000 sq km of land — much of it forest and farms — will be cleaned up as workers power-spray buildings, scrape soil off fields, and remove fallen leaves and undergrowth from woods near houses. The goal is to make all of Fukushima livable again. But as scientists, engineers, and ordinary residents begin this massive task, they face the possibility that their efforts will create new environmental problems in direct proportion to their success in remediating the radioactive contamination.

“Decontamination can be really effective, [but] what you have is a tradeoff between dose reduction and environmental impact,” says Kathryn Higley, a radioecologist at Oregon State University who has studied several decontamination sites in the United States. That’s because the radioactive particles the Japanese are trying to get rid of can be quite “sticky”. Removing them without removing large amounts of soil, leaves, and living plants is nearly impossible. The Ministry of Environment estimates that Fukushima will have to dispose of 15 to 31m cubic metres of contaminated soil and debris by the time the decontamination projects end. Costs are predicted to exceed a trillion yuan.
Given these drawbacks, an International Atomic Energy Agency fact-finding mission advised the Japanese authorities to “avoid over-conservatism” in their decontamination plans — in other words, not to clean up more than necessary to protect human health. Yet the health impacts of long-term exposure to low levels of radiation are not entirely clear. Many scientists believe exposure to even very low levels can slightly increase cancer risk, and many Fukushima residents feel they should not be forced to live with that risk — or the undercurrent of fear it brings……

Human exposure can be lowered without cleansing the entire landscape, of course. Japan’s bans on hunting bears and wild pigs, selling wild mushrooms, and growing rice in certain areas fall into this category; so does the recommendation from Fukushima’s agriculture department that farmers add potassium fertiliser to moderately contaminated fields in order to minimise cesium uptake by crops. As for forests, the focus for the time being is on decontaminating only patches close to homes because most people spend little time in remote woods.

But because the most heavily contaminated parts of Fukushima are, like the village in Kawamata, a hilly mosaic of houses, woods, and fields, the government can’t leave nature entirely untouched. Houses backed by wooded hills are very common, as are fields in small valleys; in both cases, runoff from uphill can recontaminate lowlands. Intense public concern over contaminated food, meanwhile, means many farmers want to clean up their land as quickly and thoroughly as possible.

Japan’s decontamination efforts are focused mostly on the radionuclides caesium-134 and caesium-137, which are currently present in approximately equal amounts and have half-lives of two and 30 years respectively. Although other radionuclides have been found in Japan, these two pose the greatest long-term threat to human health through ingestion and external exposure. Radiocaesium has been found in all of Japan’s prefectures, but is most highly concentrated within an oblong swath that extends about 50km north-west of the plant, and to a lesser extent throughout eastern and central Fukushima Prefecture…..

“You remove leaf litter from the forest floor and radiation levels fall,” said Shinichi Nakayama, a nuclear engineer at the JAEA who is overseeing the 19 decontamination pilot projects planned or underway. “You take away the deeper layers and they fall more. But you take it all away and the ecosystem is destroyed. Water retention goes down and flooding can occur.”…..

Past studies have shown that cancer rates rise in populations exposed to a dose of 100 millisieverts (mSv) of radiation. They reveal much less about the situation in Fukushima, where lower doses will remain for many years. (Measurements taken in Fukushima City in late December, for instance, ranged from .33 to 1.04 microsieverts per hour; sustained for a year, that adds up to doses of 2.9 to 9.1mSv.) The International Commission on Radiological Protection recommends that the general public be exposed to a yearly dose of no more than 1 to 20 mSv following a nuclear accident; those two numbers represent the difference between a decontamination effort confined to about 500 sq km and one encompassing much of Fukushima prefecture and beyond…..

The release of contaminated water from the crippled Fukushima nuclear complex last year stoked concerns about how that radioactivity might affect marine life in the Pacific. While the ocean’s capacity to dilute radiation is huge, Elizabeth Grossman reported last year that nuclear isotopes were already moving up the local food chain…..

Ten months after the nuclear disaster, trust in the authorities is nearly non-existent. Without it, Japan’s government risks the biggest cleanup fiasco of all: a decontamination effort that carries huge financial and environmental costs but still fails to convince Fukushima residents that their homes, farms, and forests are safe once again. http://www.guardian.co.uk/environment/2012/jan/09/fukushima-cleanup-environmental-disaster?newsfeed=true

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January 10, 2012 - Posted by | environment, Japan

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