Climate's Current and Future Effect on Arsenic Uptake in Rice

Abstract:

Rice is a critical food that often contains high levels of arsenic. This public health threat largely results from biogeochemical processes that occur in flooded rice paddies, which are affected by climate variation. Our study examined the relationship between short and long-term variation in precipitation and temperature on the uptake of arsenic in Cambodian rice. We used spatially-resolved climate data from NOAA weather stations and indices, the Monsoon Asia Drought Index, and PERSIANN satellite data to construct historical climate records and to link them to measured rice-As levels and grain yield. We discovered a consistent downward trend in yearly precipitation since 2001, and these values linked to indices of El/La Niño/a (ENSO) intensity after a 7-9 month lag. ENSO-related precipitation anomalies were directly correlated to rice-arsenic levels. This study also accounted for long-term trends in riverine flooding and fertilizer use on nutrient content in soil. Temperature and nutrient levels most significantly affect microbial metabolism, which creates reducing conditions that solubilize arsenic, and plant growth. This data suggests that, without proper adaptation and field management, future climate variability could adversely affect rice arsenic levels and human health for the many who depend on these crops as a food source.