Since March 2020 the world has been forced into a new normal where masks and social distancing have become part of the new status quo. Researchers around the globe are doing their best to understand this novel virus. One way that researchers have been exploring testing for presence of COVID-19 is through water sampling. Researchers around the globe are testing wastewaters for the presence of COVID-19.
A researcher in Duluth went to the public beaches along Lake Superior to test for the virus. Although water is not a natural environment for the virus, due to the density of people attending beaches it becomes a risk. The purpose of testing Lake Superior was to contribute to forming clear, scientific information for decisions with regards to water-related activities.
Testing wastewater has also been used to create a database to help detect outbreaks. Sewage water has been successful at detecting other viruses such as polio. COVID-19 can be found in fecal matter with symptomatic or asymptomatic results.
Wastewater data of COVID-19 can be a contributory factor to monitoring the presence of COVID-19. COVID-19 can show up in the sewer system before known cases and is therefore an important indicator. Although, it should be noted that the even if COVID-19 is not detected in wastewater, that the virus could still be present within the community. COVID-19 levels in wastewater can play an important role in monitoring trends within a community. The concentrations of COVID-19 within wastewater cannot be used to determine the number of cases within a community, more research is needed to understand the relationship between covid-19 wastewater concentrations and infected members of the community.
Wastewater testing for covid-19 has been used in communities that are at higher risk for COVID-19, communities where there is limited or unavailable testing, and dense populated areas such as urban centers.
Samples taken from the wastewater plant are less variable due to the higher number of peoples feces present. Depending on what the use of data is for different sampling intervals are required. For testing once a week is used for testing the presence of COVID-19 within a community. If wanting to detect trends, at least 3 sample are needed within the sampling period. Testing once a month or other infrequent intervals can determine the presence of COVID-19 within the community.
Samples can be taken from untreated wastewater such as the waste from household or buildings. To determine the concentration of COVID-19 present, the sampel typically has to be concentrated to get a reliable result. Samples can also be taken from primary sludge that is composed of primary solids that have settled out after the primary treatment. COVID-19 tends to concentrate in sludge which gives this type of sampling an advantage over untreated wastewater samples. This reduces the volume of the sample needed as well as the need to concentrate the sample. Sludge samples come with their own complications such as chemical additives from the treatment plant, interference with laboratory methods due to an increase of interfering compounds and the addition of recycled waste streams from other parts of the treatment plant.
Around Canada, there are many parts of the country that have introduced wastewater testing to monitor covid-19 levels. McMaster University in Hamilton started tracking the wastewater on its campus to act as an early warning sign for outbreaks. Other areas such as the Durham Region, Ottawa, Montreal, Vancouver, Toronto, and a variety of other regions across the country have implanted the testing of COVID-19 in wastewater with clinical testing to develop a better understanding of this novel virus.