Arsenic (As) exposure from consumption of rice can be
substantial, particularly for the population on a subsistence
rice diet in South Asia. Paddy rice has a much enhanced As
accumulation compared with other cereal crops, and practical
measures are urgently needed to decrease As transfer from
soil to grain. The researchers investigated the dynamics of As speciation in the soil solution under both flooded and aerobic conditions and compared As accumulation in rice shoot and grain in a greenhouse experiment. Flooding of soil led to a rapid mobilization of As, mainly as arsenite, in the soil solution. Arsenic concentrations in the soil solution were 7-16 and 4-13 times higher under the flooded than under the aerobic conditions
in the control without As addition and in the +As treatments
(10 mg As kg-1 as arsenite or arsenate), respectively.