A toxic substance similar to the pollutant polychlorinated biphenyl, or PCB, has been found in the breast milk of Japanese women, according to a group of Japan-based scientists.

On Tuesday [Sept. 4], the group announced at a session of the ongoing international conference Dioxin 2007 in Tokyo its discovery of polychlorinated/brominated coplanar biphenyls, or Co-PXBs, in mothers' milk. The contaminants are thought linked to the eating of fish.

The group is urging authorities to add Co-PXBs to a list of toxic substances being monitored under a law aimed at controlling dioxin. The toxicity level of Co-PXBs is apparently similar to that of PCBs.

The group warned that the adverse effects of Co-PXBs on babies have possibly been underestimated.

"It was the first discovery of the contamination of humans by these materials," said Soichi Ota, associate professor of medicine at Setsunan University in Osaka Prefecture, who led the group.

"One of the causes of the human contamination is believed to be the intake of fish, as it has been confirmed Co-PXBs contaminated fish in many regions in the world," Ota said.

"It will be an urgent task to assess the effect on human beings and determine the origin," Ota said, referring to the possibility that Co- PXBs may also originate from incinerated garbage or factory wastewater.

The group of scientists said they detected 0.42-1.41 picograms of Co- PXBs per gram of fat in the breast milk of seven women in Japan aged 21-33.

Co-PXBs were also found in meat and fish from regions around Japan as well as minke whales in the Antarctic Ocean.

(C) All rights reserved

f