High voltage power lines in Sweden trap cancer-causing pollutants in their electric fields, according to a new study, potentially raising health risks for people who live beneath them.
It's a decades-old question: does living near power lines make people sick? For the most part, studies have shown little beyond a weak up-tick in leukemia among children who live near electrical lines. Laboratory animals exposed to electrical and magnetic fields have shown no effect whatsoever.
Case closed, it would seem. But what if electrical fields corral air pollution, concentrating it in a small area? Scientists have wondered whether toxins like polychlorinated biphenyls (PCBs) and other compounds might gather under power lines in this way.
Researchers at the University of Kalmar in Sweden have now shown for the first time that this phenomenon is real. They took samples from pine needles at several sites directly beneath a 400 kilovolt power line in southern Sweden, and at distances up to several miles away.
Trees growing directly beneath the lines had about double the amount of PCBs on their needles as those plants that were some distance away, the researchers found. The elevated levels were still below anything that would be considered hazardous, but it raises the possibility that other air pollutants may get trapped in the electric field as well.
"We didn't measure anything except PCBs," study leader Tomas Oberg said. "But we could have looked at dioxins or polycyclic aromatic hydrocarbons (PAHs); there's no reason they wouldn't behave the same way."
The increased pollutant concentrations are likely the result of the electric field causing microscopic dust particles laced with pollutants to become charged. That charge makes them more likely to stick to nearby surfaces.
The study was published in the journal Atmospheric Environment.
It's an intriguing finding, but Oberg cautioned that it is far too soon to draw conclusions about any potential health risks.
"You cannot extrapolate this to human health risks," he said. "But there is definitely a significant increase in deposition of semi-volatile organic compounds here."
John Moulder of the Medical College of Wisconsin in Milwaukee isn't impressed.
"While I can't dismiss it, I can't get very excited about it either," Moulder said of possible health risks. "First, I'd want to go and check to see if there is any evidence that children with leukemia have higher body burdens of PCBs. If it turns out that they do, I might get a lot more excited about it."