Arsenic uptake and speciation in vegetables grown under greenhouse conditions
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The accumulation of arsenic (As) by vegetables is a potential human exposure pathway. The speciation of As in vegetables is an important consideration due to the varying toxicity of different As species. In this study, common Australian garden vegetables were hydroponically grown with As-contaminated irrigation water to determine the uptake and species of As present in vegetable tissue. The highest concentrations of total As were observed in the roots of all vegetables and declined in the aerial portions of the plants. Total As accumulation in the edible portions of the vegetables decreased in the order radish ≫ mung bean > lettuce = chard. Arsenic was present in the roots of radish, chard, and lettuce as arsenate (AsV) and comprised between 77 and 92% of the total As present, whereas in mung beans, arsenite (AsIII) comprised 90% of the total As present. In aerial portions of the vegetables, As was distributed equally between both AsV and AsIII in radish and chard but was present mainly as AsV in lettuce. The presence of elevated As in vegetable roots suggests that As species may be complexed by phytochelatins, which limits As translocation to aerial portions of the plant.
KeywordsArsenic Bioavailability Contamination Risk assessment Speciation Vegetables
The authors would like to acknowledge the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment for it’s generous research support and the Centre for Environmental Risk Assessment and Remediation at the University of South Australia for laboratory and analytical support.
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