Accumulation of Arsenic in Tissues of Rice Plant (Oryza 1 sativa L.) and its Distribution in Fractions of Rice Grain

26 A study was conducted to investigate the accumulation and distribution of arsenic in 27 different fractions of rice grain (Oryza sativa L.) collected from arsenic affected area of 28 Bangladesh. The agricultural soil of study area has become highly contaminated with 29 arsenic due to the excessive use of arsenic-rich underground water (0.070±0.006 mg l, 30 n=6) for irrigation. Arsenic content in tissues of rice plant and in fractions of rice grain of 31 two widely cultivated rice varieties, namely BRRI dhan28 and BRRI hybrid dhan1, were 32 determined. Regardless of rice varieties, arsenic content was about 28 and 75 folds higher 33 in root than that of shoot and raw rice grain, respectively. In fractions of parboiled and 34 non-parboiled rice grain of both varieties, the order of arsenic concentrations was; rice hull 35 > bran-polish > brown rice > raw rice > polish rice. Arsenic content was higher in non36 parboiled rice grain than that of parboiled rice. Arsenic concentrations in parboiled and 37 non-parboiled brown rice of BRRI dhan28 were 0.8±0.1 and 0.5±0.0 mg kg dry weight, 38 respectively while those of BRRI hybrid dhan1 were 0.8±0.2 and 0.6±0.2 mg kg dry 39 weight, respectively. However, parboiled and non-parboiled polish rice grain of BRRI 40 dhan28 contained 0.4±0.0 and 0.3±0.1 mg kg dry weight of arsenic, respectively while 41 those of BRRI hybrid dhan1 contained 0.43±0.01 and 0.5±0.0 mg kg dry weight, 42 respectively. Both polish and brown rice are readily cooked for human consumption. The 43 concentration of arsenic found in the present study is much lower than the permissible 44 limit in rice (1.0 mg kg) according to WHO recommendation. Thus, rice grown in soils 45 of Bangladesh contaminated with arsenic of 14.5±0.1 mg kg could be considered safe for 46 human consumption. 47