Abstract
Contamination of arsenic (As) in paddy soils has drawn much attention in the past decades. Phosphate based fertilizers are commonly used in paddy field. Elevating speciation and distribution of As is essential to assess the risk of As in paddy soils. In this study, we investigated effects of phosphate on the solubility of As (arsenite and arsenate) in two paddy soils over a wide pH range, by combing the Ligand and Charge Distribution (LCD) model to reveal the influence mechanisms. Contrasting effects of phosphate on As speciation were observed in the suboxic and anoxic soil. Under suboxic conditions, phosphate inhibited Fe and As reduction probably due to stabilization of Fe-(hydr)oxides, but increased soluble arsenate concentration as a result of competitive adsorption between arsenate and phosphate. In an anoxic soil, phosphate stimulated Fe and As reduction and caused increases of arsenite in soil solution under both acidic and neutral/alkaline pH. The understanding obtained in this work can be used in future to explain and predict the environmental process of anionic pollutants such as arsenate, arsenite and phosphate in paddy fields as well as in natural soil/sediment-water systems.
| Original language | English |
|---|---|
| Title of host publication | Arsenic in the Environment: Bridging Science to Practice for Sustainable Development As2021 |
| Subtitle of host publication | Proceedings of the 8th International Congress and Exhibition on Arsenic in the Environment (As2021), June 7-9, 2021, Wageningen, The Netherlands |
| Editors | A. van der Wal, A. Ahmad, B. Petrusevski, J. Weijma, D. Savic, P. van der Wens, E. Beerendonck, P. Bhattacharya, J. Bundschuh, R. Naidu |
| Place of Publication | London |
| Publisher | CRC Press |
| Pages | 127-128 |
| ISBN (Electronic) | 9781003317395 |
| DOIs | |
| Publication status | Published - 2023 |