The effects of wetting and drying on chromium and other metal mobility.

摘要

This study looks at the effects that wetting and drying has on Cr mobility in wetland soils. The source of the chromium was a former leather tannery that operated from the early 1900's to 1958. At the wetland site, the dominant form of Cr is Cr (III). A previous study done at the wetland site reported that soils that underwent saturation changes in the field released higher levels of chromium to solution during laboratory leaching studies. This study investigated four questions (1) is there evidence that wetting and drying enhances chromium mobility? (2) does the duration of drying affect chromium mobility? (3) do aerobic microbes play a role in chromium mobility during wetting and drying? (4) how does chromium behavior compare to other elements?; The results of this study indicate that wetting and drying affects chromium mobility. Concentrations of chromium increased under wetting and drying cycles and concentrations of chromium decreased when the soils are always wet. Soils that were not completely dried did not behave the same as samples that were always wet or completely dried. From the results of this study, the role of microbes in the mobilization of chromium can neither be supported nor denied. Finally, chromium behaves differently than Fe, Mn, and Sr under wetting and drying conditions.