HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Ye, Z. H. Articles by Terry, N. Search for Related Content PubMed PubMed Citation Articles by Ye, Z. H. Articles by Terry, N. GeoRef GeoRef Citation Agricola Articles by Ye, Z. H. Articles by Terry, N. Related Collections Water Quality Wetlands and Aquatic Processes Heavy Metals Water Pollution

TECHNICAL REPORT
Wetlands and Aquatic Processes

Trace Element Removal from Coal Ash Leachate by a 10-Year-Old Constructed Wetland

Department of Plant and Microbial Biology, Univ. of California at Berkeley, 111 Koshland Hall, Berkeley, CA 94720

* Corresponding author (nterry{at}nature.berkeley.edu)

Received for publication August 1, 2000. This study investigated the ability of a 10-yr-old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. The trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0–5 cm) of the sediment profile tended to be higher than the lower layers (5–10 and 10–15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).

Abbreviations: AMD, acid mine drainage • NPDES, National Pollution Discharge Elimination System