Cyanobacteria and toxin dynamics in drinking water sources

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In the past decade, there has been an increase in the numbers and extent of cyanobacterial blooms in Canada and worldwide. In Canada, many communities obtain their drinking water from sources impacted by cyanobacteria. In water bodies affected by the blooms, cyanobacteria and cyanotoxins can accumulate within drinking water treatment processes and disrupt water treatment. The overall research goal is to characterize and quantify the risk posed by cyanobacteria and cyanotoxins at impacted drinking water treatment plants. The long-term objective is to develop a methodology for drinking water treatment plant operators to assess the risk in real-time using models and real-time monitoring approaches that are needed for risk management at affected drinking water treatment plants. The specific research objectives are to: (1) determine the fate of a suite of cyanotoxins in relation to phycocyanin used for in vivo monitoring, (2) identify the bacteria that are associated with cyanobacterial blooms and determine whether they are beneficial or detrimental for water supplies, (3) integrate the kinetic model of cyanotoxin fate into a hydrodynamic model to determine the transport of cyanobacteria and the fate of cyanotoxins to drinking water intakes affected by cyanobacterial blooms, (4) compare model and/or laboratory results with monitoring at three drinking water treatment plants affected by recurrent cyanobacteria blooms, and (5) adapt a methodology for cyanobacterial/microbial risk assessment at Canadian drinking water intakes. Three drinking water sources will be equipped with in vivo phycocyanin probes for continuous monitoring of cyanobacterial densities throughout the study. High frequency bloom event samples will be collected at the field sites for taxonomic counts of algal species and concentrations of cyanotoxins. A series of laboratory experiments will be performed to determine the fate of a series of cyanotoxins and phycocyanin via sorption, photodegradation, and biodegradation processes. The interactions between phycocyanin and the degradation of toxins will be determined. The laboratory results will be used to develop a kinetic model of cyanotoxin fate and will be integrated into a newly developed and original 3D hydrodynamic model of cyanobacterial transport at Missisquoi Bay, one of the three study sites. A unique characteristic of cyanobacteria is their ability to control their movement within the water column, and thus their position will be controlled partly by hydrodynamic forces in addition to their buoyancy. Thus, cyanobacteria do not behave like most waterborne contaminants as they are capable of controlling their position within the water column. Our model will integrate this unique behaviour of cyanobacteria in order to understand cyanobacteria and cyanotoxin risk at drinking water treatment plants. The proposed research will leverage extensive equipment resources available through a grant from the Canada Foundation for Innovation for monitoring cyanobacteria and toxins and previous work on the development of a new hydrodynamic model of cyanobacteria transport. Ongoing collaborations with municipal drinking water providers in Ontario and Québec will also be leveraged and will provide a unique research opportunity for the training of highly qualified personnel (HQP) who will benefit from the use of state of the art research equipment in addition to direct interaction with the water managers and utilities who are among those who will benefit from the research produced. In addition, the research environment at Polytechnique Montréal is highly supportive and HQP will be trained within a group with a strong record of training HQP and an extensive network of local, national and international collaborators.