Vol. 8, Issue 6 (2020)
Fractionation and speciation of arsenic in transplanted summer rice in an arsenic endemic area of West Bengal, India
Author(s): B Sinha and K Bhattacharyya
Abstract: Widespread arsenic (As) contamination in West Bengal, India is of great concern as it affects millions of people due to its toxicity. Groundwater, when used for irrigation, helps entry of arsenic into the food chain via a soil-plant-animal continuum. In this study the extent of geo accumulation is measured in order to assess the degree of As contamination in soil. A sequential fractionation study of As revealed that the Fe/Mn bound As has emerged to be most predominant fraction in all the experimental soils, sharing 38.2 to 73.3% of total soil As recovered from the soils under study while the least proportions were retrieved from water soluble fractions. The variation in fractions may be attributed to the mineralogical make-up of soils along with some physicochemical factors. Arsenic speciation study showed that As-V appeared to be the major species while As (III) was found at a minor concentration.. The extraction efficiency of the selected reagent was observed to be substantially low in a number of soils as the majority of As is strongly bonded to Fe, Al and Mn particles of the soil. Determination of arsenic (As) species in rice is necessary because inorganic As species are more toxic than organic As. Total arsenic was determined by inductively coupled plasma mass spectrometry; arsenite, arsenate, monomethylarsonic acid, and dimethyarsinic acid were quantified by high-performance liquid chromatography- inductively coupled plasma mass spectrometry. The analysis of a rice flour certified reference material (SRM-1568-a) were evaluated for quality assurance. The use of 2M TFA for extraction with an isocratic mobile phase was optimized for extraction and employed for arsenic speciation in rice. The extraction method showed a high recovery of arsenic. Most of the As species in rice were noticed to be inorganic [Arsenite (As-III), Arsenate As-V]. It appeared very clear from the present study that inorganic arsenic shared maximum arsenic load in rice straw while in grains it is considerably low. As species recovered from rice grain and straw are principally As-III and As-V with a little share of DMA and almost non-detectable MMA and As-B.
Pages: 2615-2621 | 170 Views 72 Downloads
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How to cite this article:
B Sinha, K Bhattacharyya. Fractionation and speciation of arsenic in transplanted summer rice in an arsenic endemic area of West Bengal, India. Int J Chem Stud 2020;8(6):2615-2621.
