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

Abstract

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 l -1 for drinking water. The paddy soil gets contaminated from the irrigation water and thus enhancing the 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).

Assessment of Arsenic Accumulation by Different Varieties of Rice (Oryza sativa L.) Irrigated with Arsenic-contaminated Groundwater in West Bengal (India)

“…25) and grain (0.15 ± 0.03−0.59 ± 0.09) parts. This finding is in agreement with the findings by Liu et al [19], Rahman et al [9] and Bhattacharya et al [8]. According to Liu et al [20] the iron oxides or iron plaques formed around root of the rice plant are responsible for the arsenic binding in root.…”

“…Similar observations were previously reported by Alam et al [14], Williams et al [7] and Rahman et al [9]. In our previous study we had observed relatively higher translocation (0.19-0.39) of arsenic in the Red Minikit variety as compared to the translocation (0.1-0.16) by a local rice variety, Megi [8]. Rahman et al [9] reported that arsenic translocation from root to shoot (straw) and husk was much higher in a hybrid rice variety as compared to those by studied four other non-hybrid rice varieties.…”

“…Williams et al [7] reported that consumption of arsenic-contaminated rice on a regular basis with total arsenic content of 0.08 mg/kg would be as hazardous as drinking arsenic-contaminated water of concentration 0.01 mg/l. In our previous study we had observed an appreciable high efficiency in translocation of arsenic from straw to grain (0.1−0.39) as compared to arsenic translocation from root to shoot (0.04-0.11) in the rice plant [8].…”

“…In vivo studies conducted in the study area revealed that different rice varieties have different potential in accumulating arsenic from the same arsenic-contaminated irrigation water and paddy field soil [8,9,10,11]. The induction of arsenic in human food chain through consumption of rice thus imposes community health risk in arsenic affected areas of West Bengal [12,13].…”

Experiment for Arsenic Accumulation into Rice Cultivated with Arsenic Enriched Irrigation Water in Bangladesh

“…The use of arsenic contaminated ground water in irrigation for a prolong period of time may increase the concentrations of arsenic in soil and crops [12]. The paddy soil gets contaminated from the irrigation water and thus enhancing the bioaccumulation of arsenic in rice plants [13]. Elevated arsenic concentrations in rice grain were found from many parts of Bangladesh [14].…”