Distribution of Arsenic in Rice Grain from West Bengal, India: Its Relevance to Geographical Origin, Variety, Cultivars and Cultivation Season

Roy Chowdhury, Nilanjana; Das, Antara; Joardar, Madhurima; Mridha, Deepanjan; De, Ayan; Majumder, Sharmistha; Mandal, Jajati; Majumdar, Arnab; Roychowdhury, Tarit

Abstract

Groundwater arsenic contamination has been a staggering issue for the last 45 years. When the contaminated water is used for irrigational activities, the problem aggravates. Bengal delta is mainly reliant on rice as the staple diet and its cultivation often requires irrigation water during summer due to scarcity of fresh water and insufficient rainfall. Therefore, in arsenic exposed area, the use of contaminated groundwater can introduce arsenic into the soil–plant system. Astonishingly, rice grain accumulates up to 10 times more arsenic than other regularly harvested crops and its accumulation differs with geographical location, rice variety, cultivars and cultivation season. Importantly, arsenic concentration of paddy is highly dependent on the primordial arsenic concentration in irrigation water and soil. Geographical attributes of an area are the most significant factors of arsenic content in rice grains, as they are the chief influencer of soil arsenic concentration. In this study, the contamination quotient of rice grain arsenic is determined by the average values from four sampling sites namely North 24-Parganas, Nadia, Kolkata and West Medinipur districts of West Bengal, India and the values are 300, 215, 190, and 137 µg/kg, respectively. Apart from geographical origin, rice grain arsenic concentration also differs with cultivar. So here, rice grains are classified into three different categories according to their arsenic accumulation and assimilation capacity. The maximum amount of rice cultivars in the entire study area are medium accumulators; range of arsenic concentration is > 100–300 µg/kg (n = 45) with an average value of 178 ± 41 µg/kg. Simultaneously, arsenic concentration of rice grain depends on various factors; however, variety is one of the key players. Parboiling with arsenic contaminated water act as a “factor enhancer” during this process in arsenic exposed area. Our study found that sunned rice grains contain lower arsenic (188 μg/kg) compared to the parboiled one (268 μg/kg). Concurrently, the fourth factor is cultivation season. In Bengal delta, paddy cultivation is practiced in two seasons: pre-monsoonal and monsoonal season. The data depicts that monsoonal grain contains lesser amount (224 ± 63 µg/kg) of arsenic than pre-monsoonal (528 ± 434 µg/kg) grain. This can be interpreted by the theory of dilution, because in monsoon season, rainwater mixes with the waterlogged irrigation field and dilutes the initial arsenic concentration. Transport of arsenic-contaminated rice grain grown in arsenic endemic areas to the non-endemic sites and consequent dietary intakes leads to great threats for the local inhabitants.

Citation

Roy Chowdhury, N., Das, A., Joardar, M., Mridha, D., De, A., Majumder, S., …Roychowdhury, T. Distribution of Arsenic in Rice Grain from West Bengal, India: Its Relevance to Geographical Origin, Variety, Cultivars and Cultivation Season. In Global Arsenic Hazard. Environmental Science and Engineering. Springer. https://doi.org/10.1007/978-3-031-16360-9_23

• Online Publication Date: Dec 3, 2022
• Deposit Date: Sep 19, 2023
• Publisher: Springer
• Book Title: Global Arsenic Hazard. Environmental Science and Engineering
• ISBN: 9783031163609
• DOI: https://doi.org/10.1007/978-3-031-16360-9_23