| Abstract
| - Management of selenium (Se) -contaminated agriculturaldrainage water is one of the most important environmentalissues in California. To evaluate the feasibility of utilizingconstructed wetlands to remediate Se-laden drainage waterand the role of biological volatilization in Se removal, 10 flow-through wetland cells were constructed in 1996 inCorcoran, California. The monthly monitoring study fromMay 1997 to December 1999 showed that the vegetatedwetlands were capable of significantly reducing Se from theinflow drainage water; an average of 69.2% of the totalSe mass in the inflow was removed. Most of the Se wasretained in sediment, and <5% of the Se was accumulatedin plant tissues. Selenium volatilization was highest inthe rabbitfoot grass wetland cell, where 9.4% of the Seinput was volatilized over a 2-year period. Volatilization wasgreater in spring and summer than in fall and winter. Forexample, in May and June of 1998, 35 and 48%, respec-tively, of the Se entering the rabbitfoot grass cell wasvolatilized, whereas in the winter months, <5% was vola-tilized. The feasibility of using constructed wetlands forSe remediation, methods for the enhancement of Sevolatilization, and the importance of considering potentialSe ecotoxicity are discussed.
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