Researchers develop method to check arsenic accumulation in rice crops using fertiliser
KOLKATA: Researchers from Jadavpur University, School of Environmental Studies in association with Department of Botany, University of Calcutta have developed a method of prevention of arsenic accumulation in rice crops cultivated in arsenic-rich groundwater regions through the use of sodium sulphate fertiliser.
The research study published in Elsevier Journal 'Environmental Pollution' in 2022 assumes significance as rice (Oryza sativa L.) is considered as the staple food for 50 per cent of the world's population and presence of higher level of arsenic in rice (mainly inorganic in character which is toxic and carcinogenic) has been posing a serious threat worldwide; and moreover, consumption of this contaminated rice by human is causing health risks.
"Our research has revealed that the sulfate application significantly (p ≤ 0.05) enhanced the chlorophyll, tiller number, grains per panicle, grain and biomass yield under arsenic stressed condition. The sulfate application also reduced the oxidative stress and antioxidant activity in rice plants. Sulfate fertigation improved the accumulation of total sulphur and reduced the uptake and translocation of arsenic in rice plants," Dr. Tarit Roychowdhury, the corresponding author of School of Environmental Studies, Jadavpur University and an arsenic expert, said. The reduction percentages of arsenic in cooked parboiled and sunned rice with correspond to raw rice ranged from 55.9-74 per cent and 40.3-60.7 per cent, respectively. However, the sulfate application and cooking of parboiled rice reduced the potential non-cancer and cancer risk as compared to sunned rice. The S80 treatment and cooking of parboiled rice reduce the arsenic exposure for both children and adults by 51 per cent as compared to cooked sunned rice under S80 treatment and this trend was similar for all the treatments in their study.
According to Roychowdhury, a pot experiment with different levels of sulfate dosage (0, 20, 40, 60 and 80 mg/kg) was set up in this study to explore the influence of sulfate fertiliser on rice plant growth, yield, and arsenic accumulation in rice grain. Apart from arsenic bioaccumulation in rice grains, the arsenic fraction of cooked rice was quantified, and the health risks associated with cooked rice consumption were also investigated.
Arsenic concentration in rice grain was reduced by 50.1 per cent in S80 treatment (80 mg of sulfate/kg of soil) as compared to S0 set."Hence, sulfate application in soil can be recommended to produce safer rice grains and subsequent cooking of parboiled rice grain with low-arsenic contaminated water needs to be done to avoid any potential health risk in arsenic endemic areas," Roychowdhury added.
