Evidence mounts for PCB sperm damage

A new report has added to the growing body of evidence against gender bending chemicals but has also thrown up a few surprises.

Scientists publishing in the online journal Human Reproduction looked at the affect of polychlorinated biphenyls (PCBs) on the sperm of 700 men in a pan-European study.

But while they found sperm was being damaged their results indicated exposure to the chemicals alone was not sufficient to cause fertility problems.

PCBs are organic compounds that were used in hundreds of industrial processes before people became aware of the threat posed to health and the environment and they were phased out.

However, huge quantities of the chemicals were produced and due to their persistent nature are still commonplace in soils, water and wildlife.

While the study, led by Italian scientist Dr Marcello Spano, offers some reassurance in terms of reproduction, it does not suggest the chemicals are harmless.

It showed that the average test subject had suffered damage to 10% of sperm from the PCB exposure.

Fertility problems do not begin to arise until 20% of sperm is damaged and men with damage to more than 40% have a negligible chance of fathering a child.

The researchers therefore concluded that PCB exposure could be a factor in male fertility problems if sperm suffered additional damage from other sources.

Another surprise unearthed by the study was the fact that in general the higher the exposure to PCBs had been, the more damaged the sperm but one group bucked this trend.

Samples from almost 200 Greenland Inuits were included in the study and showed no indication that high exposure meant more damage.

The research team said it was impossible to conclude whether the anomaly was due to differences in lifestyle, genetic makeup or other, so far unknown, factors.

The scientists warned that the overall results of the study, while encouraging, were not comprehensive as they had only tested the affects of two BPCs, a family of chemicals with over 200 members.

By Sam Bond

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