Efforts to protect Tokyo’s tap water from radiation leaked by a damaged nuclear-power plant have led to a run on Indonesian coconut husks.
Granulated charcoal, made of shells of coconuts and oil-palm kernels, is being used by treatment plants in Tokyo and neighboring regions to filter tap-water supplies. 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.”
Iodine-131 is selectively taken up in the thyroid gland, where it can cause cancer. Levels reported in Tokyo on March 22 and 23 exceeded the recommended limit for infants. The increase was probably caused by contaminated rain and dust falling on the water catchment area, Ozeki said. Levels of I-131 since have fallen, and none has been detected since March 28, he said.
“We haven’t seen the rain since then and the figure has fallen and stabilized,” Ozeki said today. The extra charcoal has probably helped, though tests haven’t been taken for comparison, he said.
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.
Kuraray has gained 9.9 percent the past two weeks in Tokyo, almost triple the benchmark Topix index’s advance. The stock fell 1.5 percent to 1,100 yen at the 3 p.m. close today.
Suppliers are asking at least 300 yen ($3.58) a kilogram (2.2 pounds) for orders for the next 12 months, said Toi, the Chiba official. The local government paid between 208.95 yen and 260.40 yen last year, he said.
Neighboring Saitama prefecture will seek bids again after the initial quoted price jumped at least 20 percent, said Hisashi Fukushima, a water control official. Saitama is seeking 350 tons for the year ending March 2012, compared with the usual 200-300 tons, he said.
More than 3,000 miles away on the Indonesian island of Batam, charcoal supplier PT General Carbon Industry says that, for the first time, buyers of coconut-derived charcoal are coming from China. What’s more, they are seeking as much as 2 1/2 times the company’s monthly production, said Tonny, PT General’s marketing manager, who goes by one name.
“I’m not sure what it’s for, but it’s possibly for re-export to Japan,” Tonny said.
The magnitude-9 quake, Japan’s strongest on record, caused a tsunami that crippled Tokyo Electric Power Co.’s Dai-Ichi nuclear power plant in Fukushima, 135 miles north of Tokyo, enabling radiation to escape.
Treatment stations in Japan plan to double their use of charcoal in the wake of the contamination threat, said Makoto Kurosawa, an equities analyst at CLSA Asia-Pacific Markets in Tokyo, who recommends investors buy Kuraray shares.
Kuraray got about 4 percent of its 332.9 billion yen revenue from activated charcoal in the year ended March 2010. Additional demand for the product may boost operating profit by 1.7 percent in the year ending March 2012, Kurosawa said in an e-mail.
“They are beefing up what are normal water-cleansing activities in a municipal water-supply system,” said Stephen Lincoln, a chemistry professor at the University of Adelaide in Australia. “This would certainly be pretty effective.”
Restaurateurs are also buying charcoal to purify water, said Kohichi Shiratori, a wholesaler in central Tokyo. Customers are buying more than 50 40-gram (1.4 ounce) packets of the odor-absorbing material daily, compared with one or two a day usually, he said.
Shiratori has increased orders by fivefold for the packs, which go for as much as 580 yen each, he said.
Sri Lankan Palms
“Restaurants and other businesses are stockpiling charcoal because of their concern about the water,” Shiratori said.
Orders have risen fivefold during the past three weeks, said Toshiya Ueda, who sells charcoal made from Sri Lankan oil palms online in Osaka for 2,000 yen a kilogram. Most of his customers are Tokyo-based and want 5 kilograms to 25 kilograms.
“I just had an inquiry from a foreign company asking if I can send 5 tons,” Ueda said.
Tokyo, with an urban sprawl encompassing about 35 million residents, gets more than three-quarters of its water from the Arakawa and Tone rivers that trace to four dams in Gunma, about 87 miles northwest of the city, and one in Saitama.
Before reaching Tokyo households, tap water passes through one of a dozen plants for six hours of treatment. The process includes using charcoal to absorb impurities, polyaluminum chloride to make contaminants clump together, ozone to disinfect and a 2.5-meter (8-foot) charcoal filter to capture solids.
Tokyo’s government ordered plants to add as much as six times more activated charcoal than usually used in emergencies, as well as extra polyaluminum chloride, the water bureau’s Ozeki said.
The charcoal absorbs organic radioactive contaminants and the polyaluminum chloride will help take out metallic salts, said Lincoln, who teaches nuclear and environmental chemistry.
Tokyo officials handed out about 240,000 bottles of water last month after levels of iodine-131 measured at a treatment facility in Katsushika ward on March 22 reached 210 becquerel per kilogram, or more than double the recommended 100 Bq/kg limit for infants. The recommended limit for adults is 300 Bq/kg.
“Authorities have to be seen doing something positive and definite to ameliorate the situation and restore confidence,” said Peter Burns, former chief executive officer of the Australian Radiation Protection and Nuclear Safety Agency.
“The sorts of doses we’re talking about are the same that people would get flying around in an airplane for a few hours.”