International Journal of Plant & Soil Science

Two pot experiments were conducted to examine the effect of arsenic (As) concentration both in irrigation water and in soil on the As content in vegetables grown in a glass greenhouse. In the first experiment, spinach (Spinacia oleracea), green amaranth (Amaranthus viridis) and gima kalmi (Ipomoea aquatica) were grown in soil containing 10 mgAskg^-1, where the irrigation water contained two As levels (0.1 and 0.5 mg L^-1). In the second experiment, gima kalmi (Ipomoea aquatica) was grown in As spiked soil at different levels [10 (control), 15, 20, 30, and 50 mgAskg^-1 soil] and with irrigation water without As contamination. The As concentration (mg kg^-1 DW) and As accumulation (µg plant^-1) in the edible part of the plants increased significantly with increasing As concentrations in irrigation water and/or soil. When plants were irrigated with As contaminated water, the As concentration of the edible part exceeded its maximum limit (0.5 mg kg^-1) in spinach and green amaranth at 0.5 mg L^-1 of As, but gima kalmi had a smaller amount than the other vegetables. Gima kalmi had the characteristics of a lower As accumulation. Therefore, the risk level of As in irrigation water was suggested to be 0.1 mg L^-1 for vegetables. When gima kalmi was grown in elevated levels of As contaminated soil, the As concentration of gima kalmi, even being a low As accumulator, exceeded the maximum limit at the level above 20 mgAskg^-1 soil. The risk level of As in soil, therefore, was suggested to be 20 mg kg^-1. The risk value of As concentration in irrigation water and/or in soil needs to be investigated in detail by using many vegetables and/or soils.