Systematic assessment of SARS-CoV-2 virus in wastewater, rivers anddrinking water–A catchment-wide appraisal

Abstract

Human coronaviruses (HCoVs) attracted attention in 2002 with the severe acute respiratory syndrome (SARS)outbreak, caused by the SARS-CoV virus (mortality rate 9.6%), and gained further notoriety in 2012 with theMiddleEastrespiratorysyndrome(MERS) (mortality rate 34.3%). Currently, the worldis experiencinganunprec-edented crisis due to the COVID-19 global pandemic, caused by the SARS-CoV-2 virus in 2019. The virus can passto the faeces of some patients, as was the case of SARS-CoV and MERS-CoV viruses. This suggests that apart fromthe airborne (droplets and aerosols) and person-to-person (including fomites) transmission, the faecal–oralroute of transmission could also be possible for HCoVs. In this eventuality, natural water bodies could act as avirus reservoir of infection. Here, the temporospatial migration and attenuation of the SARS-CoV-2 virus in mu-nicipal wastewater, the receiving environment, and drinking water is evaluated, using the polymerase chain re-action (PCR), in the South African setting. SARS-CoV-2 viral RNA was identified in raw wastewater influent butwas below the detection limit in the latter treatment stages. This suggests that the virus decays from as earlyas primary treatment and this could be attributed to wastewater's hydraulic retention time (2–4 h), composition,and more importantly temperature (>25 °C). Therefore, the probability of SARS-CoV-2 virus transportation inwater catchments, in the eventuality that the virus remains infective in wastewater, appears to be low in theSouth African setting. Finally, catchment-wide monitoring offers a snapshot of the status of the catchment in re-lation to contagious viruses and can play a pivotal role in informing the custodians and downstream water usersof potential risks embedded in water bodies