Kamis, 21 Juli 2011
Granulated charcoal, made of shells of coconuts and palm kernels, is being used by treatment plants in Tokyo and neighboring regions to filter tap water supplies and protect the city’s water from radiations leaked by a damaged nuclear power plant, according to a report last month from www.bloomberg.com. Prices for the absorbent carbon material have risen as much as 44 percent since the March 11 earthquake and tsunami that triggered the radiation threat, said Yoshio Toi, a spokesman for the municipal government in Chiba, a prefecture neighboring Tokyo.
Treatment plants are trying to remove any traces of radioactive matter, such as iodine-131, known to cause thyroid cancer, and convince customers that water supplies are safe. Some Tokyo facilities more than quadrupled the amount of activated charcoal used in filtration after a March 21 sample contained iodine-131 that exceeded the safe limit for infants. “Tokyo is ordering more activated charcoal as we deplete our stocks,” said Gen Ozeki, a spokesman for the city’s Bureau of Waterworks. “It’s not just Tokyo doing this, others are taking extraordinary measures for their water, too, so charcoal is becoming scarce.” Kuraray Co., which produces about 24,500 tons of a year of activated charcoal, is receiving orders for “several hundred tons” daily from utilities in and around Tokyo, said Takeshi Hasegawa, a spokesman for the Tokyo-based company. He declined to comment on prices.