The distinctive chemistries of sulfur, carbon and strontium provide scientists with new, more accurate ways to track pollution from mountaintop mining sites and to distinguish it from contamination from other sources.
"Essentially, we found that these elements have unique isotopic fingerprints, meaning we can use them as diagnostic tools to quantify mountaintop mining's relative contribution to contamination in a watershed," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.
The newly identified tracers will be especially useful in watersheds with more than one source of potential contamination, he said. "Because they allow us to distinguish if contaminants are coming from natural sources, fracking and shale gas development, coal mining, coal ash disposal, or other causes."
Vengosh and his team's findings were published today in the online edition of the peer-reviewed journal Environmental Science & Technology.
The researchers measured the chemical and isotopic compositions of water samples collected monthly from 23 locations along West Virginia's Upper Mud River and its tributaries between May and December 2012.
They found that the isotopic signatures of sulfur (in sulfate), carbon (in dissolved inorganic carbon) and strontium from water samples collected from tributaries adjacent to mountaintop mining sites are distinguishable from those collected from unaffected upstream waters. They also found that the strontium isotope ratio is a sensitive tracer for selenium contamination, one of the major pollutants of mountaintop mining.
In mountaintop mining, companies use explosives and heavy machinery to clear away surface rocks and extract shallow deposits of high-quality coal. The companies typically dispose of the waste rock in adjacent valleys, where they bury existing headwater streams.
Previous studies by the Duke team and others have shown that runoff from these "valley fills" contains elevated levels of salts and selenium, a known fish toxin. The contamination can persist and accumulate in downstream waters for decades after active mining stops and the fills are reclaimed.
By conducting tests that simulated the natural leaching of contaminants from local rocks, Vengosh and his team were able to characterize the chemistry of the different geological formations that end up as waste rock in these fills. They found significant differences in strontium isotope ratios and selenium concentrations in streams flowing from reclaimed valley fills versus those flowing from active fills.
"This helps us further pinpoint the source of contamination by linking it directly to the type of rocks in the valley fills," Vengosh said.
The Upper Mud River flows through sparsely populated areas of southern West Virginia as a headwater stream. For about 10 kilometers, the river passes through the Hobet 21 surface mining complex, which has been active since the 1970s and is among the largest in the Appalachian coalfields.
Vengosh's co-authors were Ty Lindberg, Brittany Merola, Nathaniel Warner, Alissa White, Gary Dwyer and Richard Di Giulio, all of Duke's Nicholas School, and Laura Ruhl of the University of Arkansas at Little Rock. Ruhl received her Ph.D. from Duke in 2012.
Funding for the study came entirely from the Nicholas School of the Environment.
"The Isotopic Imprints of Mountaintop Mining Contaminants," Avner Vengosh, T. Ty Lindberg, Brittany R. Merola, Laura Ruhl, Nathaniel R. Warner, Alissa White, Gary S. Dwyer and Richard T. Di Giulio. Environmental Science & Technology, August 15, 2013 DOI: 10.1021/es4012959
Tim Lucas | EurekAlert!
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy