Monday, April 18, 2011

Future Farming in Fukushima Prefecture

The radioactive fall out in Fukushima is a concern for many, but the farmers and residents of the prefecture are the ones with the real concerns. There is great concern by many that purchase food stuff grown in the prefecture, that the meats and produce be safe.

One area that the prefecture can be compared to is Bikini Atoll, the site of hydrogen bomb tests following World War II. This is a very interesting comparison in that it involves both real and legal assessment of the risks. Legally, the once and future residents want the cleanest possible conditions which have much lower background radiation standards than many places in the world. A battle between the US Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC)is at the heart of the issue.

To many, including the NRC, the EPA regulatory limits are impractically restrictive. From the Bikini Atoll website, "To give one an ideas of how strict this 15-millirem standard is, the EPA stated that the standard means that a person living eleven miles from the Yucca Mountain site, the distance to which the standard applies, will absorb less radiation annually than a person receives from two round-trip transcontinental flights in the United States. The EPA also stated that background radiation exposes the average American to 360-millrem of radiation annually, while three chest x-rays total about 18-millirem." The Yucca Mountain case was used by the Bikinians to press for tighter clean-up standards.

It is understandable that people are worried and afraid of radiation. The standards are so poorly defined that few, even experts in the field, are in agreement to what is reasonable. 100 millirem, equivalent to 1,000 microsieverts per year is considered a reasonable background dosage even though many places in the world have higher natural background radiation doses. To my knowledge, there are no studies showing that 1,000 millirems a year background have any indication of increase health risk. The 100 millirem standard appears to already be very conservative which is equivalent to approximately 0.1 microsieverts per hour.

1,000 millirem per year (~1.0 microsieverts per hour)is greater than the effective annual average combination dose (background and other exposure)of 3000 microsieverts per year (~0.34 microsieverts per hour), but much less than areas with high natural background radiation and no evident radiation health risk. "In Guarapari, Brazil, a city of 80 000 inhabitants built on the seaside, peak measurements made by EFN on the thorium-rich beach were as high as 40 microSv/hour (about 200 times higher than the average natural background radiation in other areas of the world)." Based on other regions with higher background radiation, it would seem that 1 to 10 microsieverts per hour is not an unreasonable estimate of safe background exposure.

Ultimately, that decision should be up to the residents of area impacted by the Fukushima NPP accident to make. Another question farmers in the area would have is the uptake of radioactive isotopes by crops. Cesium 137 is the primary fall out isotope. By the same study of Bikini Atoll, potassium fertilizers inhibit plant uptake of cesium 137. Proper fertilization to build potassium levels along with normal tilling and erosion, should enable most effected farmland to be productive without any significant increase in normal radiation level.

Realistically, the radiation damage is much less than most in the press have indicated. Legally, is a different matter. Many residents may opt for much tighter standards and the larger compensation they are likely to win through the courts.

The situations, both in Japan and Bikini Atoll, illustrate the need for much clearer definition of radiation exposure standards. With the inconstant and overly conservative current limits, the nuclear industry may not be viable. Moving to more realistic standards is sure to be opposed by anti-nuclear groups responsible for the much tighter standards that are in place now. It will be interesting to see if logic or passion wins.

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