Coronavirus concentration in waste water continues decrease

The latest results of the waste water study led by the University of Tartu show that the amount of coronavirus in waste water samples has further decreased over the last week. Only Ida-Viru County and southern Estonia show higher readings than the index characterising the average situation in Estonia.

The indexes describing the average coronavirus concentration in waste water in different regions of Estonia are declining everywhere. According to the principal investigator, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, virus level is low in more than half of the sampling sites. In this week’s map there are no places with very high virus concentration.

How and where are tests gathered?

Waste water samples are collected at the beginning of every week in all Estonian county centres, cities with more than 10,000 inhabitants and, if necessary, in smaller settlements. 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. In smaller places, spot samples are taken, showing the virus level in waste water at the moment of sampling. Spot samples are more easily affected by various factors and should therefore be used 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 to estimate the spread of the virus before clinical cases are detected. The Health Board is regularly informed of the results. In collecting the samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the waste water treatment plants of Estonian cities. The samples are analysed at the laboratories of the University of Tartu Institute of Technology.

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

Further information: Tanel Tenson, Professor of Technology of Antimicrobial Compounds, University of Tartu, 5344 5202, tanel.tenson@ut.ee