Controlling exposure to As and Cd from rice via irrigation management
Date
2024-07-29
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Environmental Geochemistry and Health
Abstract
Irrigation management controls biogeochemical cycles in rice production. Under flooded paddy conditions, arsenic becomes plant-available as iron-reducing conditions ensue, while oxic conditions lead to increased plant availability of Cd in acidic soils. Because Cd enters rice through Mn transporters, we hypothesized that irrigation resulting in intermediate redox could simultaneously limit both As and Cd in rice grain due to As retention in soil and Mn competition for Cd uptake. In a 2 year field study, we used 6 irrigation managements that varied in extent and frequency of inundation, and we observed strong effects of irrigation management on porewater chemistry, soil redox potentials, plant As and Cd concentrations, plant nutrient concentrations, and methane emissions. Plant As decreased with drier irrigation management, but in the grain this effect was stronger for organic As than for inorganic As. Grain organic As, but not inorganic As, was strongly and positively correlated with cumulative methane emissions. Conversely, plant Cd increased under more aerobic irrigation management and grain Cd was negatively correlated with porewater Mn. A hazard index approach showed that in the tested soil with low levels of As and Cd (5.4 and 0.072 mg/kg, respectively), irrigation management could not simultaneously decrease grain As and Cd. Many soil properties, such as reducible As, available Cd, soil pH, available S, and soil organic matter should be considered when attempting to optimize irrigation management when the goal is decreasing the risk of As and Cd in rice grain.
Description
This article was originally published in Environmental Geochemistry and Health. The version of record is available at: https://doi.org/10.1007/s10653-024-02116-x. © The Author(s) 2024
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This research was featured in UDaily on 08/30/2024 at https://www.udel.edu/udaily/2024/august/toxic-metal-leafy-greens-rice-research-angelia-seyfferth-matt-limmer/
Keywords
water management, aerobic rice, altenate wetting and drying, trace metals, geohealth, good health and well-being, clean water and sanitation, responsible consumption and production
Citation
Limmer, M.A., Seyfferth, A.L. Controlling exposure to As and Cd from rice via irrigation management. Environ Geochem Health 46, 339 (2024). https://doi.org/10.1007/s10653-024-02116-x