Bioavailable phosphorus (P) reduction is less than mobile P immobilization in lake sediment for eutrophication control by inactivating agents. (1st February 2017)

• Record Type: Journal Article
• Authors: Wang, Changhui; He, Rui; Wu, Yu; Lürling, Miquel; Cai, Haiyuan; Jiang, He-Long; Liu, Xin
• Is Part Of: Water research. Volume 109(2017)
• Page Start: 196
• Page End: 206
• Publication Date: 2017-02-01
• Subjects: Eutrophication -- Lake -- Bioavailability -- Phosphorus-inactivation agents; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.11.045
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Phosphorus (P) immobilization by inactivating agents in the sediment of eutrophic lakes to reduce immediately available P in lake water is often crucial for mitigating nuisance eutrophication symptoms, such as cyanobacterial blooms. Macrophytes and phytoplankton, however, can directly utilize P from the sediment for growth. Accordingly, a comprehensive analysis of the P bioavailability in lake sediment amended with two promising P-inactivation agents, namely Phoslock ® and drinking water treatment residue (DWTR), was investigated in both short- and long-term studies (20 and 180 d). Phosphorus-availability was assessed using six chemical extraction methods and Hydrilla verticillata and Microcystis aeruginosa growth tests. The results showed that Phoslock ® and DWTR significantly reduced mobile P (NH4 Cl and Na2 S2 O4 /NaHCO3 extractable P) in lake sediment, while P bioavailability that was assessed by different methods showed considerable deviations. Interestingly, appropriate bioavailable P chemical extraction methods were determined based on linear correlation analysis, and further comparison indicated that reduction of bioavailable P by DWTR (<55% for macrophyte available P) and Phoslock ® (<17% for cyanobacteria available P) were clearly less than the mobile P immobilization (>75%) at recommended dosages, which was probably caused by the capability of macrophyte and cyanobacteria to utilize various fractions of P (except the residual P) in amended sediment under proper illumination. Therefore, DWTR and Phoslock ® can effectively reduce P release from lake sediment, but the potential bioavailable P may pose uncertainties for eutrophication control in lakes that typically have regular sediment re-suspension. Overall, an evaluation of the bioavailable P pool in the lake ecosystem should be essential for successful lake geo-engineering. Graphical abstract: Highlights: Different methods led to varied bioavailable P estimation in amended sediment. The growth of M. aeruginosa was not well reduced by P inactivating agents. Bioavailable P reduction was less than mobile P locking by inactivating agents. Macrophyte and cyanobacteria can utilize various P in amended sediment. Bioavailable P assessing is crucial for successful lake geo-engineering.