• Kyodo News


An organofluoric compound suspected of causing cancer is polluting water throughout Japan, particularly around the city of Osaka, where high concentrations have been detected in people’s blood, a study by a group of researchers showed Monday.

The compound, perfluoro-octanoic acid, or PFOA, is believed to be released during the manufacture of fluorine-related products, such as water repellents.

Since it is not yet known whether high concentrations of PFOA affect human health, the group is urging that further research on the compound be conducted.

The study concluded that major sources of the suspected carcinogen must be present around Osaka but could not provide concrete details.

The group, led by Akio Koizumi, a professor at Kyoto University, checked about 80 points on rivers across the country in 2003 and detected PFOA at all of the sites, confirming the contamination.

At most of the points, the group recorded less than 20 nanograms of PFOA per liter of river water, but it reached 456 nanograms in the Ina River in Hyogo Prefecture and 140 nanograms in the Yodo River in the city of Osaka.

However, 67,000 to 87,000 nanograms of PFOA were detected in samples taken from an area near a sewage plant along the Ai River, which is a branch of the Yodo.

The group also took blood samples from around 200 people in 10 areas throughout the country and found particularly high levels of PFOA in residents of Kyoto, Osaka and Nishinomiya.

PFOA detected in tap water in Osaka was about 300 times higher than in Sendai.

The group also took water samples from two wells near the Ai River last year while conducting a test with the Osaka Prefectural Institute of Public Health. The test detected 8,300 nanograms and 57,000 nanograms of PFOA in the wells, suggesting the contamination may be spreading in underground water.

Masatoshi Morita, a professor of environmental science at Ehime University, said the PFOA levels found by Koizumi’s group are among the highest known worldwide.

Although little is known about the toxic nature of PFOA, the compound tends to accumulate in humans, Morita said. Further study is necessary to examine the extent of the pollution, its sources and its potential impact on human health, he said.

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