Arsenic uptake in bean and cabbage grown in silty and sandy soil and irrigated with arsenic containing water

The uptake of arsenic was studied in bean (Phaseolus vulgaris L.) and cabbage (Brassica oleracea L. var. capitata L.) in an open greenhouse pot culture with sand and silt soil as substrate. The plants were irrigated with water containing sodium arsenate at concentrations 0.05 and 0.2 mg As L-1. The total arsenic concentration of the different plants parts was determined by ICP-MS, following microwave-assisted acid digestion. The As concentration in the bean was in the order: root>shoot>bean pod and in cabbage: root>leaves. Increasing As concentration in the irrigation water resulted in decreased edible biomass production in bean, while in cabbage the edible biomass production increased. At the highest dose (0.2 mg As L-1) if a person consumes about 450g of bean then their As intake will be: 0.9 µg from bean grown in sand and 0.72 µg from bean grown in silt. If 450g of cabbage is consumed then the As intake would be: 22.5 µg from cabbage grown in sand and 12.15 µg from cabbage grown in silt. Considering the WHO recommended MTDI limit of 2 µg kg-1 body weight, both bean and cabbage can be consumed at the highest As treatment level of 0.2 mg L-1.