title: Chromium(VI) transport and fate in unsaturated zone and aquifer: 3D Sandbox results.
abstract: The simulation of Cr(VI) behavior in an unsaturated zone and aquifer, using a 3D experimental set-up were performed to illustrate the distribution, transport and transformation of Cr(VI), and further to reveal the potential harm of Cr(VI) after entering the groundwater. The result indicated that chromium(VI) was transported in the vertical direction, meanwhile, was transported in the horizontal direction under the influence of groundwater flow. The direction and distance away from the pollution source zone had great effect on the chromium(VI) concentration. At the sampling sites near the pollution source zone, there was a sudden increase of chromium(VI) concentration. The concentration of chromium(III) concentration in some random effluent samples was not detected. Chromium had not only transported but also had fraction and specie transformation in the unsaturated zone and aquifer. The relative concentration of residue fraction chromium was decreased with time. The content of Fe-Mn oxide fraction chromium was increased with time. The relative content of exchangeable and carbonate-bound fraction chromium was lower and the content variations were not obvious. Chromium(VI) (91-98%) was first reduced to chromium(III) rapidly. The oxidation reaction occurred later and the relative content of chromium(VI) was increased again. The presence of manganese oxides under favorable soil conditions can promote the reoxidation of Cr(III) to Cr(VI).
authors.affiliation: College of Resource and Environment, Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Jilin Agricultural University, Changchun 130118, China. Electronic address: zhaoxingmin0704@163.com.
authors.forename: Xingmin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa 35401, USA. Electronic address: psobecky@ua.edu.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Sobecky
authors.affiliation: College of Resource and Environment, Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Jilin Agricultural University, Changchun 130118, China.
authors.forename: Lanpo
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa 35401, USA.
authors.forename: Patrice
authors.initials: P
authors.lastname: Crawford
authors.affiliation: College of Resource and Environment, Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Jilin Agricultural University, Changchun 130118, China.
authors.forename: Mingtang
authors.initials: M
authors.lastname: Li
keywords: Aquifer; Chromium; Fraction; Species; Unsaturated zone