An evaluation of several in-lake restoration techniques to improve the water quality problem (eutrophication) of Saint-Augustin Lake, Quebec, Canada

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DOIResolve DOI: http://doi.org/10.1007/s00267-012-9840-7
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TypeArticle
Journal titleEnvironmental Management
ISSN0364-152X
1432-1009
Volume49
Issue5
Pages10371053; # of pages: 17
Subjecteutrophication; phosphorus; integrated watershed management plan; restoration technique; water quality; microcosm assay tests
AbstractIncreasing phosphorus (P) content and decreasing water quality of Saint-Augustin Lake, Quebec City, Canada, has led to implementation of an Integrated Watershed Management Plan to restore the lake. As a part of the plan, the effects of different restoration techniques on lake water quality and biological community (i.e., biological compatibility) were assessed during an isolated water enclosure study and laboratory microcosm assay, respectively. The restoration techniques include: (i) coagulation of P by alum only (20 mg L−1), (ii) active capping of sediments using a calcite layer of 10 cm, and (iii) a complete method involving both alum coagulation and calcite capping. The results showed that the total P (TP) was greatly decreased (76–95 %) by alum + calcite, followed by calcite only (59–84 %). Secchi depth was 106 % greater and chlorophyll a concentrations were declined by 19–78 % in the enclosure which received both alum and calcite. Results of the biological compatibility test showed that total phytoplankton biomass declined by 31 % in microcosms composed of alum + calcite. No significant (P > 0.05) toxic effect was found on the survival of Daphnia magna and Hyalella azteca in both alum only and alum + calcite microcosms. Although the alum + calcite technique impaired the survival of Chironomus riparius, the midge emergence was much higher compared to alum only and control. Overall, the alum + calcite application was effective in controlling P release from sediment and lowering water column P concentrations, and thus improving the water quality and aquatic life of Saint-Augustin Lake. However, the TP concentrations are still higher than the critical limit (20 μg L−1) for aquatic life and the water column remained in the eutrophic state even after treatment. Increased TP concentrations, to higher than ambient levels of the lake, in the water column of all four enclosures, due to bioturbation artefact triggered by the platform installation, likely cause insufficient dosages of alum and/or calcite applied and reduced their effectiveness.
Publication date
LanguageEnglish
AffiliationNRC Biotechnology Research Institute; National Research Council Canada
Peer reviewedYes
NPARC number21268352
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Record identifier850b1462-6add-4410-9a6e-ded81d8c2765
Record created2013-06-28
Record modified2016-05-09
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