First case of SARS-CoV-2 RNA detection in municipal solid waste leachate from Brazil

This work presents the first case of SARS-CoV-2 RNA detection in leachate collected from a transfer station in the city of São Paulo, Brazil. After calibration of the viral detection method already used for wastewater samples with a pilot leachate sample and virus fragments in laboratory, twelve polyethylene glycol concentrated leachates samples were tested by RT-qPCR. The results confirmed the presence of N1 gene in 9 of the 12 analyzed samples between epidemiological weeks 33 and 38 of the year 2021 (08/15/2021 to 09/19/2021). The occurrence of the N2 gene was only observed in 5 of the 12 samples. The concentration values for N1 and N2 genes varied between 3.1 and 4.6 log₁₀.GC·L^-1, which are values close to those measured in sanitary wastewater. This method showed to be a promising procedure to verify the presence of viral RNA in municipal solid waste leachate, being especially useful where there is no treatment system and sanitation infrastructure, which makes the conventional wastewater surveillance unfeasible.