Coronavirus level in waste water has decreased to moderate or low everywhere in Estonia

TALLINN - The latest results of the waste water monitoring study led by the University of Tartu confirm the decrease in coronavirus amounts in waste water all over Estonia; this week’s map shows no places marked with very high virus concentration. 

While just a week ago, the interactive map of surveillance results still displayed one settlement marked in dark red, which referred to a very large virus amount, the results of the recently ended stage of the study are reflected in green or yellow in nearly all places. This shows predominantly small or moderate level of coronavirus in waste water, the University of Tartu said in a press release.

Last week, the study showed very high coronavirus concentration in the area of the Viimsi-Muuga treatment plant. According to lead researcher of the study, professor of technology of antimicrobial compounds Tanel Tenson, this week the situation has changed and there are no virus carriers or only very few carriers in that area. "East-Viru County stands out on the map: the amount of coronavirus in the settlements there is mostly moderate," Tenson said.

As the coronavirus situation in Estonia has become stable now, the waste water monitoring study of July 2 is the last one this summer. 

Waste water samples are collected at the beginning of every week in all Estonian county centers, 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 Center and water companies operating the waste water treatment plants of Estonian cities. The samples are analyzed at the laboratories of the University of Tartu's Institute of Technology.