Modeling phosphorus exchange between bottom sediment and water in tropical semiarid reservoirs. (May 2020)

• Record Type: Journal Article
• Authors: Moura, Diana S.; Lima Neto, Iran E.; Clemente, Allan; Oliveira, Samylla; Pestana, Carlos J.; Aparecida de Melo, Maria; Capelo-Neto, José
• Is Part Of: Chemosphere. Volume 246(2020)
• Publication Date: 2020-05
• Subjects: Bottom sediments -- Eutrophication -- Internal load -- Mathematical modeling -- Phosphorus availability; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125686
• Languages: English
• ISSNs: 0045-6535

Abstract

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 potentially ineffective. Graphical abstract: Image 1 Highlights: Phosphorus (P) release potential was directly proportional to reservoir age. Sediments rich in iron and aluminium-bond P may have higher impact on water quality. P release rates were higher than precipitation rates. Not all P released at the anoxic phase precipitated after oxic condition was reestablished. Release and precipitation rates are well described by zero- and first-order models.