Plant-derived phenolic compounds impair the remediation of acid mine drainage using treatment wetlands

White, Rachel A.; Freeman, Chris; Kang, Hojeong. 2011 Plant-derived phenolic compounds impair the remediation of acid mine drainage using treatment wetlands. Ecological Engineering, 37 (2). 172-175. 10.1016/j.ecoleng.2010.08.008

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Official URL: http://dx.doi.org/10.1016/j.ecoleng.2010.08.008

Abstract/Summary

The use of wetlands to remediate acid mine drainage has expanded rapidly since the realisation that acid coal mine drainage running into natural sphagnum wetlands undergoes an increase in pH and a precipitation of metals. However, our study suggests that the inclusion of plants in the acid mine drainage treatment system may be questionable, due to inefficiencies caused by exudation of dissolved organic carbon (DOC), and in particular its phenolic constituents. They complex with iron, causing increased solubility, the exact opposite of what is required to facilitate amelioration. The addition of minewater to planted wetland mesocosms initially caused a decline in Fe concentrations, typically from over 1100 to a low of 75 mg L−1. However, it increased higher than 300 mg L−1 after 15 days. The rise in iron occurred concurrently with DOC and phenolic increases; 15–69 and 5–15 mg L−1, respectively, for Eriophorum angustifolium. Removal of DOC by precipitation with calcium lowered the DOC abundance, but without a simultaneous decrease in iron concentration. The concentration of one fraction of the DOC, phenolic compounds, did not decline, and we propose that the Fe was complexed with that phenolic DOC pool. The proposal was confirmed by enzymic depletion of the phenolic compounds using phenol oxidase. Our findings suggest that phenolic complexation represents a potent constraint on wetland-based bioremediation of iron in acid mine drainage.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.ecoleng.2010.08.008
Programmes:	BGS Programmes 2010 > Groundwater Science
ISSN:	09258574
Additional Information. Not used in RCUK Gateway to Research.:	Paper funded by NERC.
Date made live:	12 Mar 2013 15:32 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/500352

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.ecoleng.2010.08.008

Programmes:

BGS Programmes 2010 > Groundwater Science

ISSN:

09258574

Additional Information. Not used in RCUK Gateway to Research.:

Paper funded by NERC.

Date made live:

12 Mar 2013 15:32 +0 (UTC)