In the Cappadocia region of Turkey, the residents of the area's villages use a kind of rock rich in the mineral erionite to build their homes, says Not Exactly Rocket Science's Ed Yong. The villagers have also suffered with an "epidemic of mesothelioma" for years because of it. Since the 1970s, mesothelioma — usually a very rare form of cancer attributed in part to exposure to asbestos — has been the cause of almost half the deaths in three villages, Yong says. And Dunn County, North Dakota could be next. More than 300 miles of Dunn County's roads are paved with gravel taken from the local North Killdeer Mountains — gravel rich in erionite. In recent animal studies, researchers have found that erionite, while acting very much like asbestos, is anywhere from 200 to 800 times more effective at causing cancer than its sibling carcinogen, Yong says. "Dunn County's erionite gravel releases small brittle fibers into the air when lightly disturbed," he adds. "They're released by wheels driving overhead, the footfalls of pedestrians, or even the gentle scrapes of brooms and rakes. Once airborne, the fibers can find their way into the lungs of passers-by, accumulating in the surrounding cavity. There, they cause chronic inflammation and, over time … mesothelioma." No cases of the disease have popped up in Dunn County yet, but experts think it's only a matter of time. According to a recent study published in PNAS, there are higher-than-normal concentrations of erionite fibers in the air in Dunn County, though they're still lower than in the air found in the Turkish villages. The study, Yong says, also found that "physically and chemically, the erionite fibers released from Dunn Country roads are very similar to those that cause mesothelioma in the Turkish villages. And their effects were nigh indistinguishable when [the research team] tested them on cells taken from the lining around the pleura." The fibers from both places trigger increased activity of genes linked to asbestos-related cancers, the study found. Erionite isn't just North Dakota's problem — it's also found in California, Oregon, and Nevada, among other states. The researchers are hoping to start clinical trials later this year to look for markers in the blood that signal the beginning of mesothelioma, Yong says. Unless North Dakota wants to end up like Cappadocia, "this is not a problem that can be ignored," he adds.
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