Recent examinations of the health and environmental impacts of mountaintop mining – stripping the tops off of mountains to extract coal – has the practice looking pretty guilty. It apparently spikes birth defects, worsens chronic conditions like heart disease, and ruins land, and it doesn’t look like it will be clearing its name anytime soon. And PNAS has added one more strike to the list with new research that further demonstrates how mountaintop mining erodes long-term water quality and causes deformities in aquatic life.
Duke University environmental scientist Ty Lindberg and his team found dramatic increases in salinity and trace metal concentrations in the water immediately downstream of mountaintop mining sites in central Appalachia. Most striking about their study was just how significant the linear relationship was between upstream surface mining disturbance and downstream water contamination – the team calculated some pretty mouthwatering p-values, and their statistical analyses showed that over 85% of the increased pollutant concentration in the sampling sites could be blamed on the extent of mining disturbance in the watershed.
“The strength of these correlations is actually pretty astonishing,” Lindberg said. “You often don’t see it in these types of systems where there’s a lot of complexity.”
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Mountaintop mining, which is frequently conducted in the Appalachian region of the eastern United States, essentially blows the tops off of mountains using explosives so coal companies can extract the coal underneath. The unusable waste rock is then disposed of in the valleys and streams below, which creates fills that permanently bury streams under “tens to hundreds of meters of waste rock,” the researchers wrote. The EPA estimated that 1,944 km of headwater streams were buried between 1992 and 2002 with complete utilization of fill permits, and predicts that 2012 will see a doubling of buried stream length to nearly 4,000 km.
To assess the impacts of mountaintop debris on the adjacent watershed, the scientists collected samples from 23 sites in over 100 mining outlets that spanned about 28 square km of coal mines. After the sampling, which took place in West Virginia’s Upper Mud River between May and December 2010, the team measured concentrations of major and trace elements as well as the electrical conductivity of the water, a measure of salinity.
Their results were telling: downstream of the mine discharge outlets, dissolved rock- and coal-weathering constituents and the resulting increased conductivity of the water significantly exceeded levels that the EPA has deemed harmful to aquatic life. Meanwhile, the two sampling sites upstream of the mountaintop mines demonstrated conductivity levels within an acceptable range.
Particularly worrying was the hike in selenium concentration in the tributaries, which exceeded acceptable levels in 26 of 31 samples. Selenium – a “known fish toxin,” according to Lindberg – is frequently linked to a loss of fish populations, and also increased proportionally with surface mining. The scientists observed a high incidence of developmental deformities among fish downstream of the mining sites.
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“We show a creek chub with a pretty severe curvature of its spine,” Lindberg said. “We also show a green sunfish – it had a cranial or facial deformity indicative of selenium we found in a really small amount of sampling time.” He added that they also noticed high selenium levels in the fish gonads and livers.
With fish deformities and polluted water under its belt, mountaintop mining has a grim environmental report card. But it remains to be seen whether studies like Lindberg’s will move the politicians and coal companies who insist that mountaintop mining is essential for job creation and economic recovery. Earlier this year, Democratic West Virginia Senator Joe Manchin pledged to “do everything in [his] power” to fight the EPA’s decision to veto West Virginia’s largest ever mountaintop removal permit, the Spruce No. 1 Mine; and coal companies have been similarly menacing in their response. But science speaks for itself — Lindberg’s research is only one of a recent flurry of studies that have shown how mountaintop mining scars the landscape. We can only hope that the stakeholders are listening.
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Tara Thean is a TIME contributor. Find her on Twitter at @TaraThean. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.