In Situ Calibration of Passive Samplers for Viruses in Wastewater

Abstract

Wastewater surveillance for SARS-CoV-2 RNAhas rapidly developed worldwide. In low-prevalence settings, sampling in sewage networks is proposed to monitor community transmission. Passive samplers are cost-effective and suitable for catchments where autosamplers cannot be operated. This resulted in their pioneering applications in some countries, even though their sampling kinetics for viruses remains unclear. We conducted in situ calibration of passive sampling materials (membranes, swabs, gauzes, and tampons) for the uptake of pepper mild mottle virus (PMMoV), enterovirus, and human adenovirus 40/41. Passive samplers were deployed in wastewater influent and retrieved sequentially over 48 h. Membranes performed continuous sampling over 48 h with estimated linear sampling rates of 1 mL h-1for PMMoV, 0.3 mL h-1for enterovirus, and 33.1 mL h-1for adenovirus. Tampons and swabs showed a rapid initial uptake of viruses and reached equilibrium after 8 h, while gauze uptake rates were potentially confounded by either inhibitors or viral losses during extended exposure. Additionally, monitoring SARS-CoV-2 at 17 sewer manholes showed that the detection ratio of membranes (14 of 17) was higher than that of tampons (8 of 17). This study demonstrated the ability of passive samplers to retain viral fragments, making them a practical tool for wastewater surveillance for the detection of disease outbreaks in communities.