Effect of sulfate application on inhibition of arsenic bioaccumulation in rice (Oryza sativa L.) with consequent health risk assessment of cooked rice arsenic on human: A pot to plate study

Arsenic (As) in rice is posing a serious threat worldwide and consumption of As contaminated rice by human is causing health risks. 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 fertilizer on rice plant growth, yield, and As accumulation in rice grain. Apart from As bioaccumulation in rice grains, the As fraction of cooked rice was quantified, and the health risks associated with cooked rice consumption were also investigated. The sulfate application significantly (p ≤ 0.05) enhanced the chlorophyll, tiller number, grains per panicle, grain and biomass yield under As stressed condition. The sulfate application also reduced the oxidative stress and antioxidant activity in rice plants. Sulfate fertigation improved the accumulation of total sulfur (S) and reduced the uptake and translocation of As in rice plants. Arsenic concentration in rice grain was reduced by 50.1% in S80 treatment (80 mg of sulfate/kg of soil) as compared to S0 set. The reduction percentage of As in cooked parboiled and sunned rice with correspond to raw rice ranged from 55.9 to 74% and 40.3–60.7%, 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 As exposure for both children and adults by 51% as compared to cooked sunned rice under S80 treatment and this trend was similar for all treatments. Therefore, sulfate application in soil can be recommended to produce safer rice grains and subsequent cooking of parboiled rice grain with low-As contaminated water need to be done to avoid any potential health risk in As endemic areas.