A dioxin survey conducted by a citizens’ group confirmed dioxin pollution nationwide, with the highest concentrations in urban areas with waste incinerators, according to results presented Saturday in Tokyo.
In one of the most comprehensive studies on the issue carried out by a nongovernmental group, over 208 samples of black pine tree needles were collected by an estimated 30,000 volunteers, mainly from around the Kanto area, Hokkaido and Kyushu.
Dioxin levels in areas around Tokyo were relatively high, with levels in Kyushu only a third of those in the Kanto area. Hokkaido had an even lower dioxin level.
The highest figure in the survey — 50 picograms per gram of pine needles — came from samples taken inside the U.S. Naval Air Facility in Atsugi, Kanagawa Prefecture. The air base borders an incinerator whose operation has become a small thorn in the side of Japan-U.S. relations.
On average, samples taken in Chiba Prefecture had the highest dioxin levels at 4.48 picograms per gram of needles, with the highest levels found around Shonan, Inzai and Funabashi.
Tokyo averaged 3.81 picograms, with the highest levels being found around Tachikawa, Suginami Ward, Hoya and Hachioji. Kanagawa Prefecture came in a close third with 3.06 picograms, with Sagamihara and Aikawa posting the highest dioxin levels.
“The high levels are likely due to industrial waste incinerators,” Teiichi Aoyama, head of the Tokyo-based firm Environmental Research Institute, said when presenting the results.
Hokkaido, meanwhile, averaged 0.62 picograms per gram of needles sampled, a level akin to that found in Western countries, he said.
Dioxin concentrations in pine needles reflect dioxin levels in the air. But the survey did not include concentrations of coplanar polychlorinated biphenyls, another chemical substance similar to dioxin, said Aoyama, adding that if they did, the figures would be boosted by 20 to 30 percent.
Members of Seikatsu Club, a Kanto-based cooperative, and others paid for the 30 million yen testing fees with donations. The samples were analyzed by a Canadian firm.