title: Toxic trace element assessment for soils/sediments deposited during Hurricanes Katrina and Rita from southern Louisiana, USA: a sequential extraction analysis.
abstract: Analysis of soil/sediment samples collected in the southern Louisiana, USA, region three weeks after Hurricanes Katrina and Rita passed was performed using sequential extraction procedures to determine the origin, mode of occurrence, biological availability, mobilization, and transport of trace elements in the environment. Five fractions: exchangeable, bound to carbonates, bound to iron (Fe)-manganese (Mn) oxides, bound to organic matter, and residual, were subsequently extracted. The toxic trace elements Pb, As, V, Cr, Cu, and Cd were analyzed in each fraction, together with Fe in 51 soil/sediment samples. Results indicated that Pb and As were at relatively high concentrations in many of the soil/sediment samples. Because the forms in which Pb and As are present tend to be highly mobile under naturally occurring environmental conditions, these two compounds pose an increased health concern.Vanadium and Cr were mostly associated with the crystal line nonmobile residual fraction. A large portion of the Cu was associated with organic matter and residual fraction. Cadmium concentrations were low in all soil/sediment samples analyzed and most of this element tended to be associated with the mobile fractions. An average of 21% of the Fe was found in the Fe-Mn oxide fraction, indicating that a substantial part of the Fe was in an oxidized form. The significance of the overall finding of the present study indicated that the high concentrations and high availabilities of the potentially toxic trace elements As and Pb may impact the environment and human health in southern Louisiana and, in particular, the New Orleans area.
authors.affiliation: Environmental Research Center, Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA. honglan@mst.edu
authors.forename: Honglan
authors.initials: H
authors.lastname: Shi
authors.forename: Emitt C
authors.initials: EC
authors.lastname: Witt
authors.forename: Shi
authors.initials: S
authors.lastname: Shu
authors.forename: Tingzhi
authors.initials: T
authors.lastname: Su
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wang
authors.forename: Craig
authors.initials: C
authors.lastname: Adams
mesh_terms: D055867:Cyclonic Storms; D019015:Geologic Sediments / Q000737:chemistry*; D008145:Louisiana; D012989:Soil Pollutants / Q000032:analysis*; D014131:Trace Elements / Q000302:isolation & purification / Q000633:toxicity*
chemical_list: D012989:Soil Pollutants; D014131:Trace Elements