Improved Rice (<i>Oryza sativa</i>) Water Utilization to Reduce Arsenic Accumulation and Aquifer Overdraft

Arsenic contamination of water, soil and food is a global concern. Rice (Oryza sativa) is uniquely involved because rice is a major staple food and its culture in anaerobic soil promotes arsenic accumulation. This manuscript attempts to apprise our current understanding of arsenic in rice in terms of: (i) the severity of the arsenic problem, (ii) the various irrigation technologies being advanced to mitigate arsenic rice accumulation, and (iii) the potential for emerging water conserving irrigation systems to reduce aquifer overdraft. The leading contenders to mitigate arsenic accumulation include (i) plant breeding, (ii) irrigation technologies, (iii) soil amendments that restrict arsenic bioavailability, and (iv) groundwater purification. Recent research involving (i) wetting and drying irrigation and (ii) furrow irrigation typically conserve water and inhibit arsenic accumulation. In Missouri, furrow irrigation generally reduced rice seed arsenic concentrations to less than 0.05 mg∙kg−1. Plant breeding to both limit arsenic accumulation and tolerate increased temperatures show promise, yet detailed research needs to be expanded.