In this study the distribution of Sb concentrations and Sb species (Sb III and Sb V) in grass samples in a roadside profile were investigated. The Sb depositions on the grass surfaces are higher than the bioaccumulations of Sb in grass samples where it reaches two-fold concentrations at locations nearest to the traffic. The Sb species distribution, after a chromatographic separation, was determined using on-line isotope dilution (ID). The extraction of Sb species from contaminated grass samples was carried out using 100 mmol L-1 citric acid (pH 2.08). The concentrations of Sb species in grass show decrease with increasing distance from traffic lane with a sharp drop within the first two meters. Sb(V) concentration is at least two folds higher than Sb(III) in grass samples near the road edge. The total and bioaccumulated Sb(V) species concentrations sharply decreases with distance from the road edge, while Sb(III) concentration also decrease with distance but less pronounced as for Sb(V). Sb(III) species which is the more toxic species, could be detected in all the grass samples (washed and unwashed) independent of the sampling distance from the edge of the road. It was also observed that the majority of inorganic Sb species can be washed out by applying water to the grass.
Antimony, Speciation analysis, Isotope dilution, Grass samples, Traffic roads
