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Evaluation of simultaneous reduction and transport of selenium in saturated soil columns
Author(s) -
Guo Lei,
Frankenberger William T.,
Jury William A.
Publication year - 1999
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1998wr900074
Subject(s) - selenate , selenium , effluent , chemistry , environmental chemistry , soil water , leaching (pedology) , manure , compost , soil science , environmental science , environmental engineering , agronomy , organic chemistry , biology
Speciation plays an important role in determining the overall leachability of selenium in soil. In this study we present a mathematical model and results of miscible displacement experiments that were conducted to evaluate simultaneous reduction and transport of selenate in saturated soil columns. The experiments were carried out in organic amended (compost manure or gluten) or unamended soil, with O 2 ‐sparged or nonsparged influent solution. In all columns, reduction of selenate was fast enough to produce selenite flux in the effluent and elemental Se in the soil profile during a mean residence time of ∼30 hours. Reduction was accelerated in the presence of organic amendments and under low O 2 concentrations, resulting in an increased retardation of selenium transport as a whole. The results of our experiments show that although selenate does not sorb to solid surfaces during transport, it reduces rapidly to forms that are strongly retarded. On the basis of simulation with the consecutive reaction and transport model using parameters derived from this study, selenium is expected to be retained near the soil surface, even under extreme leaching conditions.