The virus SARS-CoV-2, which has caused the recent COVID-19 pandemic, may be present in the stools of COVID-19 patients. Therefore, we aimed to detect SARS-CoV-2 in wastewater for surveillance of SARS-CoV-2 in the population. Samples of untreated wastewater were collected from 33 wastewater treatment plants (WWTPs) of different sizes within the Czech Republic. SARS-CoV-2 RNA was concentrated from wastewater and viral RNA was determined using real-time reverse transcription polymerase chain reaction (RT-qPCR). SARS-CoV-2 RNA was detected in 11.6% of samples and more than 27.3% of WWTPs; in some of them, SARS-CoV-2 was detected repeatedly. Our preliminary results indicate that an epidemiology approach that focuses on the determination of SARS-CoV-2 in wastewater could be suitable for SARS-CoV-2 surveillance in the population.

The paper analyses dependence of water quality parameters on flow rates at several sites in the Vltava River catchment in the Czech Republic. The presented results indicate that at the monitored sites, concentrations of nitrates, suspended solids and dissolved oxygen are in direct relation to flow rate. Temperature has an inverse relationship to flow rate. Other parameters show various relationships to flow rate at individual monitored sites or do not show any statistically significant relations.

A significant amount of artificial radionuclides has been introduced into the environment in the last century during atmospheric nuclear weapons tests and the Chernobyl accident. In this study, we investigated the temporal changes of concentrations and amounts of these radionuclides ( 90 Sr and 137 Cs) in surface water and river bed sediments. In order to evaluate the artificial radionuclide contamination diminution, we used and compared two different approaches: using a kinetic equation of the first order and, if needed, dividing the monitored period into two intervals, and in addition expressing the whole process in one equation with a series of exponential functions. Effective ecological halflives were estimated as rates of decrease. In most cases, the ecological processes were proven to affect the radionuclide removal from the hydrosphere besides their radioactive decay. Furthermore, based on the assessment made, the 90 Sr and 137 Cs data were extrapolated and the radionuclide concentrations, which occurred in the hydrosphere after the fallout deposition in 1986, were estimated.

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