587 Mountaintop removal/valley fill coal mining reduces in-stream retention of ammonium

Thursday, May 21, 2009: 2:15 PM
Ambassador West
Eric R. Sokol , Department of Biological Sciences, Virginia Tech, Blacksburg, VA
Jackson R. Webster , Department of Biological Sciences, Virginia Tech, Blacksburg, VA
E. F. Benfield , Department of Biological Sciences, Virginia Tech, Blacksburg, VA
Bobbie Niederlehner , Department of Biological Sciences, Virginia Tech, Blacksburg, VA
Small headwater streams in the Appalachian Mountains are important sites of nutrient retention.  In some areas streams are being modified by mountaintop removal\valley fill (MTR) coal mining.  This process has been shown to affect macroinvertebrate assemblages, and our objective was to determine if it also affects nutrient retention.  Using the nutrient release technique, we measured ammonium uptake seasonally in 10 small streams in the Twenty-Mile Creek watershed in central West Virginia.  Five of these streams drain areas of active or recent MTR mining, and the other five have no history of coal mining although they were logged at some time in the past and variously exploited for natural gas.  Stream discharge was more variable seasonally at reference sites, and reference streams were intermittent during autumn 2007.  The length of stream reach filled by MTR mining practices was positively correlated with ammonium uptake lengths measured in winter, spring, and summer, but not autumn.  Areal uptake of ammonium was low in two MTR streams, but the other MTR streams were similar to references streams.  Our results suggest that activities associated with MTR mining, such as using nitrogen chemicals for metal precipitation or elevated sediment transport, may decrease nitrogen retention.