FIG 1.

Evolution of SARS-CoV-2 genomes in two large Barcelona wastewater treatment plants (WWTP). (A and D) Detection of the RNA-dependent RNA polymerase gene (IP2 and IP4 primers). (B and E) Detection of the envelope protein gene (E primers). (C and F) Detection of the nucleoprotein gene (N1 primers). The absence of values on a given date is due to the unavailability of aliquots to assay. Dashed lines depict limits of detection. Red, orange, and green arrows indicate phase 1, phase 2, and phase 3 of the deconfinement, respectively (Table S1).