SARS-CoV-2 data in wastewater in Quebec | INSPQ

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The information presented on this page is obtained through periodic monitoring of SARS-CoV-2 analyzes in municipal wastewater. This tool is complementary to other data available to monitor the evolution of the COVID-19 pandemic. Indeed, this indicator makes it possible to monitor trends in the spread of the virus among the population, including people who are asymptomatic or who have not been tested.

The amount of SARS-CoV-2/ varies from one treatment plant to another because the number of people served by different sewage systems also varies. This data is used to assess trends over time for the same station.

At any time, the data may be modified following improvements in techniques for collection, analysis, entry and information validation or updating.

For more details, see methodological details.

Amount of SARS-CoV-2 in wastewater by sampling site

Note that the maximum metric values ​​for each city may vary. It is not recommended to compare data from different cities, and even from different processing stations in the same city, with each other.

methodological details
  • The CentrEau-COVID University team developed the sample collection and laboratory analysis protocol used based on those in several labs in Canada and internationally, including McGill University, Polytechnic Montreal and Laval University.
  • Composite sampling of wastewater is taken over a 24-hour period by workers at treatment plants in the respective cities. Laboratory analyzes are performed at McGill University.
  • The amount of SARS-CoV-2 (or viral load) in wastewater is obtained by multiplying the concentration, that is, the number of viral gene copies measured \ml of wastewater, by the average daily flow into the wastewater network (m3/day) .
  • Certain factors can influence the expense of viral loads in wastewater. This is particularly the case for the size of the population served by sewage systems. Population size is the main reason for the undesirability of comparing data from different treatment plants with each other. You just have to track the signal of the same station over time.
  • Flushing into the sewage system affects the concentration of SARS-CoV-2 that finds its way there, diluting and filtering the virus and the particles it binds to. By controlling this flow, this makes it possible to consider the effect of snowmelt, precipitation and infiltration of water in the ground into the network, which can vary from station to station.
  • The graphs display the viral load of SARS-CoV-2 as a daily value (disabled by default) and as a 7-day moving average, which includes the values ​​for the previous three days and the following three days.
  • The viral load of the same station can vary a lot from day to day; The use of a moving average makes it possible to reduce these fluctuations.
  • With the aim of quality control, an analysis of data validity is carried out on an ongoing basis. Data deemed invalid can be removed from the graphs and/or retrospectively re-adjusted after new analyses.
  • The time between the last date of wastewater sampling and indicator availability and data dissemination are improved.
  • The method for dissemination of data is under development and may change.

data sources

See also

#SARSCoV2 #data #wastewater #Quebec #INSPQ

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