Climate change and arsenic contamination of rice: Impact of elevated soil temperature on rhizosphere arsenic biogeochemistry and arsenic uptake by rice

Rice is a globally important food crops, and arsenic contamination of rice grain threatens the health of billions of people globally. It is unclear how this health threat will change in the future as growth conditions shift due to global climate change. Knowledge of how arsenic concentrations in rice grain may change in the future is important for motivating the development of solutions to the problem and avoiding additional damage to human health. Here we present results from a laboratory experiment testing the impact of elevated soil temperature on arsenic biogeochemistry in the rhizosphere (the soil zone surrounding roots) and uptake of arsenic by rice plants. Temperatures are expected to increase in rice growing areas, and we hypothesized that increased soil temperature would increase arsenic availability and delivery to rice roots. As anticipated, we found that elevated soil temperature did increase arsenic uptake by rice; but elevated soil temperature also changed plant growth behavior and rhizosphere biogeochemistry in unanticipated ways.