title: Breakthrough of cyanobacteria in bank filtration.
abstract: The removal of cyanobacteria cells in well water following bank filtration was investigated from a source water consisting of two artificial lakes (A and B). Phycocyanin probes used to monitor cyanobacteria in the source and in filtered well water showed an increase of fluorescence values demonstrating a progressive seasonal growth of cyanobacteria in the source water that were correlated with cyanobacterial biovolumes from taxonomic counts (r = 0.59, p < 0.00001). A strong correlation was observed between the cyanobacterial concentrations in the lake water and in the well water as measured by the phycocyanin probe (p < 0.001, 0.73 ≤ r(2) ≤ 0.94). Log removals from bank filtration estimated from taxonomic counts ranged from 0.96 ± (0.5) and varied according to the species of cyanobacteria. Of cyanobacteria that passed through bank filtration, smaller cells were significantly more frequent in well water samples (p < 0.05) than larger cells. Travel times from the lakes to the wells were estimated as 2 days for Lake B and 10 days for Lake A. Cyanobacterial species in the wells were most closely related to species found in Lake B. Thus, a travel time of less than 1 week permitted the breakthrough of cyanobacteria to wells. Winter samples demonstrated that cyanobacteria accumulate within bank filters, leading to continued passage of cells beyond the bloom season. Although no concentrations of total microcystin-LR were above detection limits in filtered well water, there is concern that cyanobacterial cells that reach the wells have the potential to contain intracellular toxins.
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada.
authors.forename: Pirooz
authors.initials: P
authors.lastname: Pazouki
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada.
authors.forename: Michèle
authors.initials: M
authors.lastname: Prévost
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: McQuaid
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada.
authors.forename: Benoit
authors.initials: B
authors.lastname: Barbeau
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: de Boutray
authors.affiliation: Water Research Center, School of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia.
authors.forename: Arash
authors.initials: A
authors.lastname: Zamyadi
authors.affiliation: École Polytechnique de Montreal, Civil, Mineral and Mining Engineering Department, P.O. Box 6079, Succ. Centre-ville, Montreal, Quebec, H3C 3A7, Canada. Electronic address: sarah.dorner@polymtl.ca.
authors.forename: Sarah
authors.initials: S
authors.lastname: Dorner
mesh_terms: D000458:Cyanobacteria; D005374:Filtration; D060106:Lakes; D052998:Microcystins; D010798:Phycocyanin; D012621:Seasons
chemical_list: D052998:Microcystins; D010798:Phycocyanin
keywords: Bank filtration; Cyanobacteria; Log removal; Microcystins; Phycocyanin; Phytoplankton