Premium
Chromated Copper Arsenate–Treated Fence Posts in the Agronomic Landscape: Soil Properties Controlling Arsenic Speciation and Spatial Distribution
Author(s) -
Schwer Donald R.,
McNear David H.
Publication year - 2011
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2010.0455
Subject(s) - chromated copper arsenate , arsenic , arsenate , environmental chemistry , soil water , environmental science , genetic algorithm , arsenite , fence (mathematics) , chemistry , soil science , ecology , mathematics , organic chemistry , combinatorics , biology
Soils adjacent to chromated copper arsenate (CCA)‐treated fence posts along a fence line transecting different soil series, parent material, drainage classes, and slope were used to determine which soil properties had the most influence on As spatial distribution and speciation. Metal distribution was evaluated at macroscopic (total metal concentration contour maps) and microscopic scales (micro‐synchrotron X‐ray fluorescence maps), As speciation was determined using extended X‐ray absorption fine structure spectroscopy, and redox status and a myriad of other basic soil properties were elucidated. All geochemical parameters measured point to a condition in which the mobilization of As becomes more favorable moving down the topographic gradient, likely resulting through competition (Meh‐P, SOM), neutral or slightly basic pH, and redox conditions that are favorable for As mobilization (higher Fe(II) and total‐Fe concentrations in water extracts). On the landscape scale, with hundreds of kilometers of fence, the arsenic loading into the soil can be substantial (∼8–12 kg km −1 ). Although a significant amount of the As is stable, extended use of CCA‐treated wood has resulted in elevated As concentrations in the local environment, increasing the risk of exposure and ecosystem perturbation. Therefore, a move toward arsenic‐free alternatives in agricultural applications for which it is currently permitted should be considered.