The Interaction of Natural Organic Matter with Iron in a Wetland (Tennessee Park, Colorado) Receiving Acid Mine Drainage |
| |
| Authors: | Stefan Peiffer Katherine Walton-Day Donald L Macalady |
| |
| Institution: | (1) Limnological Station, Department of Hydrology, University of Bayreuth, D-95440 Bayreuth;(2) United States Geological Survey, Denver Federal Center, Box 25046, M5415, CO 80225, USA;(3) Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80315, USA |
| |
| Abstract: | Pore water from a wetland receiving acid mine drainage was studied for its iron and natural organic matter (NOM) geochemistry
on three different sampling dates during summer 1994. Samples were obtained using a new sampling technique that is based on
screened pipes of varying length (several centimeters), into which dialysis vessels can be placed and that can be screwed
together to allow for vertical pore-water sampling. The iron concentration increased with time (through the summer) and had
distinct peaks in the subsurface. Iron was mainly in the ferrous form; however, close to the surface, significant amounts
of ferric iron (up to 40% of 2 mmol L-1 total iron concentration) were observed. In all samples studied, iron was strongly
associated with NOM. Results from laboratory experiments indicate that the NOM stabilizes the ferric iron as small iron oxide
colloids (able to pass a 0.45μm dialysis membrane). We hypothesize that, in the pore water of the wetland, the high NOM concentrations
(>100 mg C L-1) allow formation of such colloids at the redoxcline close to the surface and at the contact zone to the adjacent
oxic aquifer. Therefore, particle transport along flow paths and resultant export of ferric iron from the wetland into ground
water might be possible.
This revised version was published online in July 2006 with corrections to the Cover Date. |
| |
| Keywords: | natural organic matter ferrous iron ferric iron wetland colloidal iron acid mine drainage pore water |
| 本文献已被 SpringerLink 等数据库收录！ |
|
