Fig. 3.
Comparison of SARS-CoV-2 concentration measured with traditional method and passive sampling
Membranes of nylon or zetapor were immersed for 4 h or 24 h in wastewater samples collected from two WWTP (sites A & B). (a) frozen wastewater, (b) freshly collected wastewater. Boxplots show the minimum, 25th percentile, median, 75th percentile, and maximum concentration/32 cm2 of membrane or /100 ml of wastewater. Kruskal-Wallis test followed by a Dunn's multiple comparisons test: *p < 0.05, ** p < 0.01, ***p < 0.001.