Study details cancer risk of Roseville rail yard

Those living downwind from Union Pacific's J.R. Davis Rail Yard in Roseville could be at higher risk of cancer than previously thought, according to a new study that looked at air quality near the massive train facility. The study found rail yard emissions contained higher levels of carcinogenic compounds than fumes from diesel trucks - up to 5.5 times more, including benzopyrene, a notorious carcinogen, called a polycyclic aromatic hydrocarbon, long implicated in a range of cancers.The report was issued Wednesday by the Sacramento-Emigrant Trails chapter of Breathe California, and led by atmospheric physics scientist Thomas A. Cahill of UC Davis and his son, Thomas M. Cahill, an environmental toxicologist at Arizona State University. It detailed how exhaust from diesel locomotive engines at the rail yard appeared to be more toxic than exhaust from truck diesel engines, due to heavier concentrations and higher molecular weights, the study's authors said. In addition, the study found evidence that soil contamination at the rail yard showed up later outside of the area - the result, researchers believe, of contaminated soil being "re-suspended" by activity such as vehicle traffic. "These studies have given us the most detailed picture of particles coming off a rail yard that has ever been achieved. There were a number of unexpected findings, including higher than expected levels of heavier polycyclic aromatic hydrocarbons and metal contaminated soils," Thomas A. Cahill said in a news release. The report also outlines a number of effective mitigation efforts to reduce health risks to residents downwind of the rail yard, including planting vegetation, upgrading operations to run more efficiently and installing indoor filtration systems.Some work on mitigating the rail yard's environmental impact has already started. Union Pacific, Placer County Air Pollution Control District other local, state and federal air pollution agencies entered into a memorandum of understanding several years ago to work on lessening emissions at the site. Last year, new technology to substantially decrease emissions from locomotives was demonstrated at the J.R. Davis yard. For more on the study, see Wednesday's issue of The Press-Tribune.