Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estuary (Portugal)

Otero, M.; Coelho, J.P.; Rodrigues, E.T.; Pardal, M.A.; Santos, E.B.H.; Esteves, V.I.; Lillebø, A.I.

Kinetics of the PO4-P adsorption onto soils and sediments from the Mondego estuary (Portugal)

2013

In order to assess the status of a North Atlantic Ocean Ecoregion (Mondego system, Portugal) after the implementation of a management programme, a study on PO4-P sorption was carried out. Considering that sorption velocity markedly determines the systems promptness to phosphorus external loading, the kinetics of the sorption of PO4-P onto estuarine sediments and the upstream agricultural soils was studied. The pseudo-second order kinetic equation gave an appropriate description of PO4-P sorption onto these soils and sediments, allowing for a quantitative comparison. For soils, the kinetic constants (k2⁎, μg−1gh−1) ranged between 0.007 and 0.017μg−1gh−1 while, in the case of sediments these ranged between 0.008 and 0.012μg−1gh−1. Results showed that the reduction of water residence time after the management action was relevant for the system status, affecting its reaction capacity to phosphorus loading.

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