Estimating the risk of cyanobacterial occurrence using an index integrating meteorological factors: Application to drinking water production

Mouhamed Ndong (1) , David Bird (2) , Tri Nguyen-Quang (3) , Marie-Laure de Boutray (1) , Arash Zamyadi (1) , Brigitte Vinçon-Leite (4) , Bruno J. Lemaire (4) , Michèle Prevost (1) , Sarah Dorner (5)

1 Department of Civil, Geological and Mining Engineering
2 Département des Sciences Biologiques [Montréal]
3 Department of Engineering
4 LEESU - Laboratoire Eau, Environnement et Systèmes Urbains
5 NSERC Industrial Chair on Drinking Water, Department of Civil, Geological and Mining Engineering

The sudden appearance of toxic cyanobacteria (CB) blooms is still largely unpredictable in waters worldwide. Many post-hoc explanations for CB bloom occurrence relating to physical and biochemical conditions in lakes have been developed. As potentially toxic CB can accumulate in drinking water treatment plants and disrupt water treatment, there is a need for water treatment operators to determine whether conditions are favourable for the proliferation and accumulation of CB in source waters in order to adjust drinking water treatment accordingly. Thus, a newmethodology with locally adaptable variables is proposed in order to have a single index, f(p), related to various environmental factors such as temperature, wind speed and direction. The index is used in conjunction with real time monitoring data to determine the probability ofCBoccurrence inrelationtometeorological factors, andwas tested at a drinkingwater intake inMissisquoi Bay, a shallowtransboundary bay in Lake Champlain, Que'bec, Canada. These environmental factors alone were able to explain a maximum probability of 68% that a CB bloom would occur at the drinking water treatment plant. Nutrient limitation also influences CB blooms and intense blooms only occurred when the dissolved inorganic nitrogen (DIN) to total phosphorus (TP) mass ratio was below 3. Additional monitoring of DIN and TP could be considered for these source waters prone to cyanobacterial blooms to determine periods of favourable growth. Real time monitoring and the use of the index could permit an adequate and timely response to CB blooms in drinking water sources.

Keywords: Wind Nutrient mass ratios; cyanobacteria; meteorological index; drinking water intake; early warning systems; wind; nutrient mass ratios

Domains: Environmental Sciences; Environmental Engineering

Mouhamed Ndong, David Bird, Tri Nguyen-Quang, Marie-Laure de Boutray, Arash Zamyadi, et al.. Estimating the risk of cyanobacterial occurrence using an index integrating meteorological factors: Application to drinking water production. Water Research, 2014, 56, pp.98-108. ⟨10.1016/j.watres.2014.02.023⟩. ⟨hal-00967649⟩