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

Moura, Diana S.; Lima Neto, Iran E.; Clemente, Allan; Oliveira, Samylla; Pestana, Carlos J.; de Melo, Maria Aparecida; Capelo-Neto, José

Authors

Diana S. Moura

Iran E. Lima Neto

Allan Clemente

Samylla Oliveira

Maria Aparecida de Melo

José Capelo-Neto



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.

Journal Article Type Article
Publication Date May 31, 2020
Journal Chemosphere
Print ISSN 0045-6535
Electronic ISSN 1879-1298
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 246
Article Number 125686
Institution Citation MOURA, D.S., LIMA NETO, I.E., CLEMENTE, A., OLIVEIRA, S., PESTANA, C.J., DE MELO, M.A. 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
DOI https://doi.org/10.1016/j.chemosphere.2019.125686
Keywords Bottom sediments; Eutrophication; Internal load; Mathematical modeling; Phosphorus availability
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