The following are further summaries and sources for further data on this issue, followed by a rebut

The following are further summaries and sources for further data on this issue, followed by a rebuttal from Dofasco Inc Proceedings of the National Academy of Sciences - Air pollution induces heritable DNA mutations

James S. Quinn, associate professor, McMaster University

Public Health Statement on PAHs

Agency for Toxic Substances and Disease Registry

The respiratory effects of air pollution are well documented. Now the results of a new study suggest that industrial pollution could cause genetic defects, too. Findings published online this week by the Proceedings of the National Academy of Sciences indicate that mice subjected to ambient air in close proximity to a steel mill had twice as many genetic mutations as their rural counterparts did.

Previous research had shown that gulls living close to steel mills in the Great Lakes region had increased rates of DNA mutations. The exact role of air pollutants was unclear, however, because the birds may have also been exposed to toxins in their water supply. In an attempt to elucidate the effect of air pollution, Christopher M. Somers of McMaster University in Hamilton, Ontario, and his colleagues housed two groups of mice in separate locations for 10 weeks. The first group was situated one kilometer downwind from two steel mills, and the second was placed in a rural setting 30 kilometers away. After being returned to the laboratory, the mice and their offspring were tested for genetic mutations. The researchers found that the mice that had lived near the mills had smaller litters, on average, than did those that lived in the country. What is more, the so-called steel mice exhibited twice as many DNA mutations as the control animals did, with the majority originating from the fathers. The authors conclude that "this is the first demonstration of heritable mutation induction in any organism as a result of ambient air pollution exposure." -- Sarah Graham

Mutagens Are in the Air

The billowing smoke from steel mills may not only make it hard to breathe, but may also cause genetic damage, according to new research in PNAS this week. Scientists have long suspected that industrial pollution poses a significant risk to the health of human and animal populations, although much of the evidence is anecdotal or confounded by factors other than air pollutants. James Quinn at McMaster University and colleagues previously found a high rate of heritable mutations in herring gull populations nesting near steel mills. However, it was unclear whether the observed effect was due to emissions in the air or contaminants in the water. To isolate and examine the effect of air pollution, Quinn and colleagues housed laboratory mice in ambient air 1 km downwind from two integrated steel mills near Lake Ontario and a rural location 30 km away. Mice exposed to air pollution from the steel mills had offspring with a greater number of DNA mutations compared to rural mice. Also, steel mill mice had slightly smaller litters than rural mice. Although the potential health effects of the mutations remain unclear, these findings suggest that some component of industrial air pollution has the potential to cause genetic damage that could adversely affect generations to come.