Modeling phosphorus exchange between bottom sediment and water in tropical semiarid reservoirs.

Abstract

This study investigated phosphorus (P) dynamics in the sediment-water interface of three distinct reservoirs located in a tropical semiarid region. Sequential chemical fractioning of the P content in the sediment and controlled experiments of the sediment-water interface were performed to understand and model the effect of the different P fractions on the exchange dynamics under anoxic and oxic scenarios. The results revealed that the older the reservoir, the higher the amount of iron and aluminum-bound P in the sediment, and that this fraction was responsible for a 10-fold increase in P concentration in the water during anoxic conditions. After aeration, P in water decreased but did not return to its initial concentration. The most recently constructed reservoir showed the lowest P concentration in the sediment and dominance of the unavailable P fraction, resulting in no potential impact on water quality. Phosphorus release and precipitation rates were well described by zero- and first-order models, respectively. Reservoirs with high P availability in the sediment, not only released more phosphorus but also presented a lower precipitation rate, resulting in higher potential damage to water quality and making some in-lake treatment techniques ineffective.

Citation

MOURA, D.S., LIMA NETO, I.E., CLEMENTE, A., OLIVEIRA, S., PESTANA, C.J., APARECIDA DE MELO, M. and CAPELO-NETO, J. 2020. Modeling phosphorus exchange between bottom sediment and water in tropical semiarid reservoirs. Chemosphere [online], 246, article ID 125686. Available from: https://doi.org/10.1016/j.chemosphere.2019.125686

• Journal Article Type: Article
• Acceptance Date: Dec 16, 2019
• Online Publication Date: Dec 17, 2019
• Publication Date: May 31, 2020
• Deposit Date: Dec 23, 2019
• Publicly Available Date: Dec 18, 2020
• Journal: Chemosphere
• Print ISSN: 0045-6535
• Electronic ISSN: 1879-1298
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 246
• Article Number: 125686
• DOI: https://doi.org/10.1016/j.chemosphere.2019.125686
• Keywords: Bottom sediments; Eutrophication; Internal load; Mathematical modeling; Phosphorus availability
• Public URL: https://rgu-repository.worktribe.com/output/819643