The CentrEau-COVID pilot project: Monitoring of SARS-CoV-2 virus in wastewater

Consult the data on the presence of the SARS-CoV-2 virus in Montreal, Quebec City, Laval and some cities under study in the Bas-Saint-Laurent/Gaspésie Region for this pilot monitoring project that went on from January 2021 to December 2021.

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    Disclaimer of liability

    The website is updated as soon as new data come in. We are working on a daily update. If recent results are not showing up for you, consider clearing your browser's cache.

    The raw data and analyses for COVID-19 in wastewater on this website are subject to validation and should not be considered definitive – adjustments may be made in the near future. There are no prescribed methods for the detection of the virus responsible for COVID-19, SARS-CoV-2, in wastewater, so these results should not be used in any regulatory context. Decisions should never be made on the basis of wastewater data alone. The purpose of generating wastewater data is to complement other public health information. This website will be continually updated with new data as results become available.

    Please note that the practice of using PMMoV* to normalise the data is still debated worldwide and remains a point of debate also for the data gathered in the province of Quebec

    The project

    Sewage testing can detect between 1 and 30 infected individuals (including asymptomatic ones) per 100,000 people in a population's sewage - this method is very attractive since it costs about 1% of the cost of individual testing. In addition, because feces contain the virus up to a few days before the person becomes ill (or not, as this method also detects asymptomatic cases), this approach allows detection of outbreaks 2-7 days before the increase in the positivity rate of clinical screening tests. Obviously, this type of testing complements individual testing by geolocating outbreaks and focusing screening efforts. This surveillance system also provides a quick indication of whether new measures (masks, confinement, curfew) are effective. Wastewater monitoring also allows us to detect the presence of new variants of the virus in the territory.

    At CentrEau, our researchers have been working since March 2020 to implement a COVID-19 monitoring and early warning system using wastewater, first using their own research funds, and since December 2020 thanks to a $1 million grant from the Fonds de recherche du Québec (FRQ). Other funding partners for this project, for a total of $1.7 million, are the Trottier family Foundation, the Molson Foundation and the National Centre for Electrochemistry and Environmental Technologies (CNETE). Professors Dominic Frigon (McGill University) and Peter Vanrolleghem (Université Laval) are the coordinators of this project. The co-investigators are Sarah Dorner (Polytechnique Montréal), Marc-André Labelle (CTE), Françoise Bichai (Polytechnique Montréal), Karine Lemarchand (UQAR), Marc-Denis Rioux (UQAR), Jean-François Lemay (CNETE), Richard Villemur (INRS), Stephanie Loeb (McGill University), Alain Létourneau (Université de Sherbrooke), as well as François Guillemette (UQTR), Slim Haddad (ULaval and CIUSSS Capitale Nationale) (non-members of CentrEau). Thanks also to all the collaborators of the project, including the INSPQ (Dr. Caroline Huot) and more than a dozen municipalities who are graciously sampling. Indeed, this research project is only possible with the participation of the municipalities covered by the project. They developed the sampling programs in conjunction with the researchers and their regional public health department, and they administer them with their municipal employees. For the data reported on this page, we thank the Services de l'eau et de l'environnement of the City of Montreal and the Service du traitement des eaux of Quebec City. A complete list of participating municipalities is forthcoming, we thank them all! Thanks also to our service providers (OClair Environnement, Thales Canada, Nosotech, Laboratoires BLS, Nordikeau and Aquatech).

    The five regions currently under study are the cities of Montreal, Quebec City and Laval, as well as the Bas-Saint-Laurent/Gaspésie region and the Mauricie-Centre-du-Québec region. For these last three regions, everything is not yet fully in place and we do not have a complete enough time series to draw conclusions at this time.

    The project researchers are collaborating with research teams at the Canadian and international levels. 


    * PMMoV: The amounts of SARS-CoV-2 found are compared to those of a virus that attacks peppers, the pepper mild mottle virus. Indeed, since the population eats enough peppers to continuously shed PMMoV in their feces, we can use this value to compare with SARS-CoV-2 and consider that both viruses are equally diluted or concentrated depending on variations in wastewater flow (rainfall, dry weather, etc.). Thus, the ratio of one to the other gives us a reliable indicator of the level of infection that does not depend on wastewater flow. 

    In order for Quebec to take advantage of this innovative surveillance approach to accelerate the detection of cases and outbreaks of COVID-19 and to facilitate the understanding of the epidemiological situation in the population, the implementation of SARS-CoV-2 wastewater surveillance at different spatial and temporal scales has been proposed: (i) at the neighborhood level and on a daily basis for urban areas, and (ii) at the scale of clusters of small municipalities (e.g., regional, county, municipalities) and on a biweekly basis for rural areas. Considering the assumed detection limit of 1-30 cases per 100,000 population, the basic design assumption is to aim for sample sizes of approximately 50,000 (rural areas) to 100,000 (urban areas). This size will allow public health to develop targeted responses.

    Basic biomolecular protocols for the detection and monitoring of SARS-CoV-2 in wastewater have been developed and validated in the last year by many laboratories in Canada and internationally, including the laboratories of S. Dorner (Polytechnique Montreal) and D. Frigon (McGill) in Quebec. Data collected in wastewater and modelled to fit the viral signal will be compared to data on COVID-19 cases identified by individual screening. This will allow the two types of information to be related and to measure the validity and usefulness of the information provided by the virus quantification in wastewater: early detection, upward, plateau or downward trend in the epidemiology of the disease.

    The quality of the wastewater data should be controlled before storage in a publicly accessible database to allow further analysis and interpretation. It is known that the viral signal is affected by different phenomena occurring between the excretion of the virus and its arrival at the sampling site (e.g. dilution and degradation). While in-house standards such as light pepper mild mottle virus (PMMoV) can help correct for some of these effects, doubts have been raised about these correction methods and correction algorithms and predictive mathematical models will be designed by our team to complement or replace these approaches. In addition, some phenomena can only really be corrected by taking advantage of knowledge about the fate of the virus during its transport from the focus to the sampling location: first-order degradation kinetics that depend on temperature, hydraulics, adsorption onto suspended solids, and transport time from different locations in the sewage basin. For these correction algorithms, in addition to the virus concentration data, metadata are collected to describe wastewater quality, sewer flows, meteorological conditions, among others.

    For tracking variants and mutations of interest, metagenomic sequencing techniques of SARS-CoV-2 viruses are applied to complement the surveillance data. Finally, ethical and governance issues are analyzed to understand the link between fields of expertise (environmental engineering and public health), and to discern possible problems of stigmatization and social acceptability in data management.

    The project dataset for wastewater treatment plants in the Quebec City area (sites qc_01 and qc_02) is now available in open-source »

    Participating institutions