Accumulation of arsenic and its distribution in rice plant (Oryza sativa L.) in Gangetic West Bengal, India

摘要

The presence of arsenic in irrigation water and in paddy field soil were investigated to assess the accumulation of arsenic and its distribution in the various parts (root, straw, husk, and grain) of rice plant from an arsenic effected area of West Bengal. Results showed that the level of arsenic in irrigation water (0.05-0.70 mg l~(-1)) was much above the WHO recommended arsenic limit of 0.01 mg 1~(-1) for drinking water. The paddy soil gets contaminated from the irrigation water and thus enhancingthe bioaccumulation of arsenic in rice plants. The total soil arsenic concentrations ranged from 1.34 to 14.09 mg kg~(-1). Soil organic carbon showed positive correlation with arsenic accumulation in rice plant, while soil pH showed strong negative correlation. Higher accumulation of arsenic was noticed in the root (6.92 ± 0.241-28.63 ± 0.225 mg kg~(-1)) as compared to the straw (1.18 ± 0.002-2.13 ± 0.009 mg kg~(-1)), husk (0.40 ± 0.004-1.05 ± 0.006 mg kg~(-1)), and grain (0.16 ± 0.001-0.58 ± 0.003 mg kg~(-1)) parts of the rice plant. However, the accumulation of arsenic in the rice grain of all the studied samples was found to be between 0.16 ± 0.001 and 0.58 ± 0.003 mg kg~(-1) dry weights of arsenic, which did not exceed the permissible limit in rice (1.0 mg kg~(-1) according to WHO recommendation). Two rice plant varieties, one high yielding (Red Minikit) and another local (Megi) had been chosen for the study of arsenic translocation. Higher translocation of arsenic was seen in the high yielding variety (0.194-0.393) compared to that by the local rice variety (0.099-0.161). An appreciable high efficiency in translocation of arsenic from shoot to grain (0.099-0.393) was observed in both the rice varieties compared to the translocation from root to shoot (0.040-0.108).