Translocation of Soil Arsenic towards Accumulation in Rice: Magnitude of Water Management to Minimize Health Risk

Abstract

Globally, the risk of arsenic (As) contamination in soil and rice is well documented across the globe. In Bangladesh, drinking water and rice are two major exposure pathways of As to humans. Therefore, the efficiency of recent technologies to reduce rice As and associated human health risks still need to be deeply investigated. In this direction, a pot experiment was performed to investigate the impact of soil As and agronomic irrigation management on rice (cv. BRRI dhan28) growth, yield, As accumulation, and finally, health risks to humans from consuming rice. Treatment combinations were made with three levels of As (0, 20, and 40 mg kg−1) having two irrigation procedures, including alternate wetting and drying (AWD) and traditional continuous flooding (CF). According to the findings, As pollution in the soil lowered the yield contributing features and rice yield, including panicle length, filled grains per panicle, sterile grains per panicle, 1000-grain weight, grain yield, and straw yield. AWD water management significantly improved the growth performance and productivity of rice. Grain yield was increased by 13% in AWD compared to CF. Rice grain and straw As concentrations were increased to 0.56 mg kg−1 and 15.10 mg kg−1, respectively, in soil with 40 mg kg−1 As and CF water management. AWD treatment significantly reduced grain and straw As contents by 16% and 28%, respectively. Increased grain, straw, and total As uptake was noticed with higher soil As concentrations. The study also found that rising soil As raised non-carcinogenic risks (HQ > 1) and carcinogenic risks (CR > 1.010–4) while AWD lowered health risks compared to CF. Thus, rice farming using AWD irrigation could be a viable and long-term solution for reducing As contamination in rice and associated human health hazards.

The Effect of Irrigation Techniques on Sustainable Water Management for Rice Cultivation System - A Review

“…However, several reports indicate that AWD irrigation can help alleviate the accumulation of AS and Hg. The levels of As and Hg in rice grains under AWD are generally lower compared to CF, with reductions ranging from 13.7-91.8% for As and 2.7-89.2% for Hg [37,38,63,64]. In comparison to the AWD, the CF promoted as accessibility in the rhizosphere, which boosted as absorption and transport to the xylem in rice via stimulating the expression of silicon transporter genes (OsLsi1 and OsLsi2), but decreasing soil available sulphur and phytochelatins production [37,64].…”

“…The levels of As and Hg in rice grains under AWD are generally lower compared to CF, with reductions ranging from 13.7-91.8% for As and 2.7-89.2% for Hg [37,38,63,64]. In comparison to the AWD, the CF promoted as accessibility in the rhizosphere, which boosted as absorption and transport to the xylem in rice via stimulating the expression of silicon transporter genes (OsLsi1 and OsLsi2), but decreasing soil available sulphur and phytochelatins production [37,64]. Additionally, in the CF-submerged rice fields, anaerobic microbes potentially metabolize the less hazardous inorganic mercury (Hg) into methylmercury (MeHg), which is effectively stored in rice grains [65].…”

Alternate wetting and drying decreases arsenic content and increases yield of rice grown in organic matter amended soil

“…The samples were dried at 60 °C in an oven for 48 hours, and then grinded homogenously for determining the As concentration in by rice grain and straw samples. About 0.5 g of sub sample was transferred in the digestion tube with 5 mL HNO3 and 2.5 mL H2O2, and allowed to stand overnight (Jahan et al, 2021). Then, the tubes containing the samples were subjected to digestion and heated slowly up to159°C for two hours, and allowed to cool.…”

Water Quality for Agricultural Irrigation and Aquatic Arsenic Health Risk in the Altay and Tianshan Mountains, Central Asia

“…The above mentioned was based on the results of health risks caused by direct contact between the human body and water bodies. However, river waters in arid areas are used as direct sources of irrigation water, and arsenic in water bodies accumulates in the soil through irrigation, then transfers to food crops, which has an impact on humans [61][62][63]. Research in the geochemical study of As in the whole chain of river-soil-crop-human also needs to be strengthened in the future, especially in the Tianshan oasis area with its high As content in the river water bodies.…”