Nature: A study of lake sediments near mining operations in Canada has shown increased levels of polycyclic aromatic hydrocarbons (PAHs), a family of organic pollutants that includes several carginogens. In a paper published in the Proceedings of the National Academy of Sciences, Joshua Kurek of Queen’s University in Kingston, Ontario, and colleagues found that the higher levels of PAHs coincide with oil sands development in the province of Alberta. Extraction of crude oil from the sands began almost a half century ago, but has ramped up significantly since the 1990s, and the environment may be suffering. “The signature of the PAHs and the timing strongly suggest that development and the refining of the oil sands plays a role in PAHs increasing in these lakes,” said Kurek. Because production is expected to double between 2011 and 2020, Alberta’s government plans to create an independent agency to monitor the situation.