The presence of SARS-CoV-2 RNA in different freshwater environments in urban settings determined by RT-qPCR: Implications for water safety

Abstract

This study is the first focused on the presence of SARS-CoV-2 in different freshwater environments in an urban setting. Groundwater and surface water reservoirs for drinking water as well as water from receiving rivers of the Monterrey Metropolitan Area were sampled repeatedly during a SARS-CoV-2 peak phase between October 2020 and January 2021, and viral RNA was measured by quantitative reverse transcription polymerase chain reaction. Forty-four percent of the groundwater samples had detectable viral loads between 2.6 and 38.3 copies/ml. A significant correlation between viral load and sucralose concentration in groundwater reaffirmed the hypothesis of leaching and infiltrating effluent from surface and/or failing sewage pipes and emphasized the importance of water disinfection. Twelve percent of the surface water dam samples tested positive for viral RNA, with values varying between 3.3 and 3.8 copies/ml. Finally, 13% of the river samples were positive for viral RNA, with concentrations ranging from 2.5 to 7.0 copies/ml. Untreated wastewater samples taken in the same period showed viral loads of up to 3535 copies/ml, demonstrating a dilution effect and/or wastewater facilities efficiency of three orders of magnitude. Variations in the viral loads in the groundwater and surface water over time and at the submetropolitan level generally reflected the reported trends in infection cases for Monterrey. The viral loads in the freshwater environments of Monterrey represent a low risk for recreational activities according to a preliminary risk assessment model. However, this result should not be taken lightly due to uncertainty regarding data and model constraints and the possibility of situations where the infection risk may increase considerably.

SARS-CoV-2 circulation in Croatian wastewaters and the absence of SARS-CoV-2 in bivalve molluscan shellfish

“…Possible implications of the SARS-CoV-2 environmental shedding by wastewaters are the contamination of surface waters and its possible spill over to the wildlife. Even though SARS-CoV-2 RNA was detected in open surface waters ( Kolarević et al, 2021 ; Mahlknecht et al, 2021 ; Rimoldi et al, 2020 ), there is no evidence for a transmission of SARS-CoV-2 via water-food-environmental media ( Adelodun et al, 2021 ). To this date SARS-CoV-2 pandemic strain was not detected to circulate in free-ranging wildlife species which may be in contact with surface waters, wastewaters and human waste in general ( Colombo et al, 2021 ; Jemeršić et al, 2021 ).…”

Robust Evaluation of Ultraviolet-C Sensitivity for SARS-CoV-2 and Surrogate Coronaviruses

“…SARS-CoV-2 has been detected by real-time reverse transcription-PCR (RT-PCR) in fecal samples ( 1 ) and in municipal wastewater ( 2 ), and transmission associated with sewage aerosols was documented during the 2003 outbreak of the closely related SARS-CoV coronavirus ( 3 ). Recently, SARS-CoV-2 was detected in groundwater, rivers, and dam water in the Monterrey, Mexico, region ( 4 ). These observations raise critical questions about the adequacy of treatment for drinking water and wastewater.…”

Monitoring the presence and persistence of SARS-CoV-2 in water-food-environmental compartments: State of the knowledge and research needs

“…Recently, Núñez-Delgado (2020) and Kumar et al (2020) raised a concern about SARS-CoV-2 presence in the environmental compartments and the potential risks of transmission through water-soil media while extending to the groundwater sources. A recent study by Mahlknecht et al (2021) reported the presence of SARS-CoV-2 RNA in different freshwater environments in an urban setting including groundwater samples, which demonstrates the ability of the virus to leach and infiltrate from surface water or leakage sewer to underground water resources. A review study by Bradford et al (2013) had earlier described the fate and transport of viruses in the environmental compartment, while a study by Ogorzaly et al (2010) demonstrated the transport of enteric viruses through the aquifer into groundwater.…”