Artificial lakes that form during rapid urbanization often fail to achieve their desired functions, and gradually become eutrophic. Whether the external discharge or internal release of nutrients dominates the eutrophication of urban lakes has rarely been reported. In this study, a lake that had been formed during ten years of urbanization had become hyper-eutrophic. TP mainly contributed to the eutrophication and algal bloom in the lake. While the release potential of TP fluctuated, TN, particularly NH3-N, was constantly released from the sediment. Concentrations of anthropogenic metals (Pb, Cu and Cr) increased with the increasing depth of the sediment. Even for a lake that had formed rapidly in a short period, the internal phosphorus released from sediment was 1.9-times higher than that of the external discharge. The dominating contribution of internal pollution from sediment requires more attention to restore and manage these urban waters.
Keywords: Cyanobacteria; Eutrophication; Phosphorus; Release; Sediment; Urban lake.
© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.