Factors influencing As and Sb bioavailability, accumulation and toxicity in agricultural plants

Various industrial activities can cause elevated concentrations of arsenic (As) and antimony (Sb) in soils, including near agricultural fields, leading to their accumulation in crops. This contamination may occur from individual metalloids or as co-contamination. Soil chemistry of the agricultural lands could be impacted by agricultural practices like addition of PO43-containing fertilisers and waterlogging (which influences on chemical speciation due to anaerobic conditions). The aim of this thesis was to understand the influence of environmental and anthropogenic factors on the bioavailability of As and Sb in soils, and their accumulation and toxicity to agriculturally important plants under individual and co-contamination scenarios. This thesis focused on soil ageing, individual verses co-contamination of As and Sb, addition of PO43-fertilisers and soil waterlogging affect. In these experiments, bioavailability was determined by sequential extraction procedure (SEP) and compared to total soil concentration. Arsenic and Sb accumulation in plant tissues were assessed and compared with SEP-bioavailable fraction in the soils. All plants were grown in a controlled environment. Arsenic and Sb concentrations in soils and plant tissues were determined by ICP-MS. Plant toxicity of Ipomoea aquatica and Brassica chinensis were assessed using measurements of root and shoot dry mass, root and shoot length, and chlorophyll content. In Oryza sativa, the measurements of tissue dry mass and lengths, tiller and panicle number were used.