Study of microbiological contamination level of surface water in MONITOX network areas before and after COVID-19 pandemic

Abstract

The microbiological contamination of the water with faecal bacteria resulting from anthropogenic activity is an important issue for population health and the assessment of the presence of pathogenic bacteria in water is a major concern for the protection of humans and animals. Coliform bacteria are indicators for the assessment of faecal pollution and a potential presence of pathogens, which is caused mainly of untreated wastewater. In this paper, a comparative study was carried out in 32 sampling sites of MONITOX network in two periods, June 2019 and June-July 2020, before and after COVID-19 pandemic lockdown, regarding the rate of the water microbiological contamination in Lower Danube (Calarasi/Silistra-Galati-Tulcea sectors, Danube Delta and Black Sea coast, from SE part of Romania, by counting of the bacteria indicators of the organic pollution (heterotrophic bacteria and total coliforms). The results demonstrate a decrease of microbiological contamination of surface water in 2020 during the COVID-19 lockdown in all the samples collected form Black Sea coast, Danube branches, Danube-Black Sea confluence, and Danube river downwards Galati town.