Coronavirus concentration in waste water has stabilised at a high level

This week’s results of the waste water study led by the University of Tartu indicate that coronavirus concentration in waste water has stabilised at a very high level. Compared to the rest of the country, south-east Estonia continues to stand out, with virus levels several times higher than elsewhere.

The map of the analysis results of the samples collected during the week has become somewhat lighter than the week before. However, according to the lead researcher of the study, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, the change has been relatively marginal. „We can consider it a good sign that the week has not brought any new places with a very high level of the virus. The next week will show whether we will see a drop in the virus concentrations. Whether the trend persists can be assessed in 2–4 weeks,” said Tenson.

Compared to the index describing the average situation in Estonia, southern Estonia continues to stand out, with the virus levels exceeding the average several times. The virus concentration in waste water has also increased in larger places in central Estonia.

How are the samples collected?

Waste water samples are collected at the beginning of every week in all county centres, cities with more than 10,000 inhabitants and, if necessary, in smaller places. Samples taken from larger cities reflect the situation of waste water passing through the treatment plant over 24 hours, giving a reliable overview of the infection level in the city. The spot samples taken in smaller places show the situation at the moment of sampling. Spot samples are more easily affected by various factors and should therefore be used in comparison over several weeks to estimate the trend, rather than get a definitive picture of the current situation.

The study is a tool helping the Health Board monitor changes in the outbreak dynamics and discover hidden outbreaks. It gives early information for estimating the spread of the virus before clinical cases are detected. The Health Board is regularly informed of the results.

In the collection of samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the water treatment plants of Estonian cities. The samples are analysed at the laboratories of the University of Tartu Institute of Technology.

For more information about the previous results of the study, see the home page of the study “Detecting coronavirus in waste water”.

The waste water study is funded by the European Regional Development Fund from the EU measure to respond to the Covid-19 pandemic.

Further information: Tanel Tenson, Professor of Technology of Antimicrobial Compounds of the University of Tartu, 5344 5202,