Latvian scientists are developing a new monitoring method that will help to determine the transfer of coronavirus to wastewater and the distribution in the environment. This is necessary in order to understand what virus-restrictive measures can be implemented and what preventive measures should be taken, taking into account not only the human-to-human virus transmission, but on a more broader scale – across the whole ecosystem. The study is carried out by Riga Technical University (RTU) together with the Latvian Biomedical Research and Studies Center (BMC) and the Institute of Food Safety, Animal Health and Environment (BIOR).
Currently, the distribution of coronavirus in the environment, the duration of its survival, human exposure mechanisms and interaction with animals have not been sufficiently studied. However, this information is important for deciding on actions in the state of emergency and relief or removal of restrictions and preventive measures in the future to prevent not only coronavirus but also possibly other more dangerous viruses.
In order to understand the mechanism of coronavirus distribution, scientists have chosen wastewater as a research site, which is one of the possible stages in the virus distribution chain. Samples have been taken from several wastewater treatment systems in Latvia and the presence of the virus has been detected in one of them. Currently, there is no evidence that the virus in the sewer is able to cause further infections, as well as the concentration of the virus has not been determined, as it is necessary to develop more precise methods for isolation or concentration of the virus.
The discovery has made it clear that «monitoring the sewer system can provide additional assurance when the spread of infection in a given area is over,» said Tālis Juhna, RTU Vice-Rector for Academic Affairs and the Head of the Water Research Laboratory. The water monitoring system will also help to develop guidelines for people activities during the virus pandemic. For example, it is recommended that employees of sewer services use protective masks, and that all citizen close the toilet lid before flushing.
Traces of the virus have been detected in sewer water samples in cities where there are Covid-19 infected people, but no cases have been reported in areas with no registered infected people. Nor has the virus been found in samples taken from wastewater after its treatment. Scientists presume that this indicates that in the wastewater treatment plants particles of the virus bind and precipitate.
Scientists will continue their research and study water samples from centralised wastewater treatment plants, hospitals and gather samples in cities over a longer period to improve this monitoring method.