Fe biogeochemistry in reclaimed acid mine drainage precipitates--implications for phytoremediation.
At a 50-year-old coal mine drainage barrens in central Pennsylvania, USA, we evaluated the biogeochemistry of acidic, Fe(III)oxy(hydr)oxide precipitates in reclaimed plots and compared them to untreated precipitates in control areas. Reclaimed plots supported successional vegetation that became established after a one-time compost and lime treatment in 2006, while control plots supported biological crusts. Precipitates were sampled from moist yet unsaturated surface layers in an area with lateral subsurface flow of mine drainage above a fragipan. Fe(II) concentrations were three- to five-fold higher in reclaimed than control precipitates. Organically bound Fe and amorphous iron oxides, as fractions of total Fe, were also higher in reclaimed than control precipitates. Estimates of Fe-reducing and Fe-oxidizing bacteria were four- to tenfold higher in root-adherent than both types of control precipitates. By scaling up measurements from experimental plots, total Fe losses during the 5-yr following reclamation were estimated at 45 t Fe ha(-1) yr(-1).
Dept. of Ecosystem Science and Management, 116 Agricultural Sciences and Industries Building, The Pennsylvania State University, University Park, PA 16803, USA. Electronic address: cxr932@psu.edu.
Claudia
C
Rojas
Carmen Enid
CE
Martínez
Mary Ann
MA
Bruns
D001419:Bacteria / Q000254:growth & development / Q000378:metabolism; D001673:Biodegradation, Environmental; D017610:Calcium Compounds / Q000737:chemistry; D003032:Coal Mining; D005290:Ferric Compounds / Q000737:chemistry; D005296:Ferrous Compounds / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D010414:Pennsylvania; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*
D017610:Calcium Compounds; D005290:Ferric Compounds; D005296:Ferrous Compounds; D010087:Oxides; D012987:Soil; D012989:Soil Pollutants; C000499:ferric oxide; C016538:lime
Acid mine drainage; Biological crusts; Fe(II) reduction; Iron oxides; Reclamation