Air-Filled Porosity as a Key to Reducing Dissolved Arsenic and Cadmium Concentrations in Paddy Soils
| Autor: | Katsuhiro Suzuki, Hidetaka Katou, Toshimitsu Honma, Ken Nakamura |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Environmental Engineering
Soil test Growing season chemistry.chemical_element 010501 environmental sciences Management Monitoring Policy and Law 01 natural sciences Redox Arsenic Soil Soil pH Soil Pollutants Porosity Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Cadmium Oryza sativa Oryza 04 agricultural and veterinary sciences Pollution chemistry Environmental chemistry 040103 agronomy & agriculture 0401 agriculture forestry and fisheries |
| Zdroj: | SC30201810100025 NARO成果DBa C30201802130009_3801.pdf 書誌情報のみ |
| ISSN: | 0047-2425 |
| Popis: | Simultaneous suppression of rice (Oryza sativa L.) uptake of As and Cd is challenging because these toxic elements are immobilized under contrasting redox conditions. Given the notion that oxygen diffusion governs redox conditions in temporarily drained paddy soil, we assume that the key to simultaneous suppression of dissolved As and Cd concentrations is air-filled porosity (AFP) of soil. The objectives of this study were to reveal relationships between AFP and dissolved As and Cd concentrations in paddy soils and to identify the optimum water management, in terms of AFP, for simultaneous reduction of As and Cd. Dissolved As and Cd concentrations were determined in soil cores collected at different depths and times during rice growing seasons. Dissolved As concentrations were appreciable (>3 µg L⁻¹) only when AFP was below a threshold value of 0.04 to 0.10 m³ m⁻³, suggesting that dissolved As was rapidly immobilized once AFP exceeded the threshold value on drainage. Dissolved Cd concentrations were roughly proportional to AFP, with higher concentrations associated with lower soil pH. Although dissolved As concentrations tended to be low in soil samples with high dissolved Cd concentrations and vice versa, both concentrations were low when AFP was slightly above the threshold value for As immobilization. The results suggest that dissolved As and Cd can be simultaneously kept at low levels by appropriate water management practices that produce AFP slightly above the threshold value for As immobilization. |
| Databáze: | OpenAIRE |
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