Short-term stability of wastewater samples for storage and shipment in the context of the EU Sewage Sentinel System for SARS-CoV-2

In context of an EU-wide surveillance system for SARS-CoV-2 in wastewater, recommended by the European Commission, the study aims to provide scientific support to the adequacy of transport conditions of samples. Three laboratories in Slovenia, Cyprus and Estonia investigated short-term, one-week, isochronous stability of wastewater samples for RT-qPCR based detection of SARS-CoV-2 genes. The stability was tested for statistical significance to determine uncertainty of quantification and shelf-life, at testing temperatures of +20°C and -20°C, relative to reference at +4 °C. Samples were collected from three WWTP influents and analysed respectively for SARS-CoV-2 genes N1, N2 (Laboratory 1), N2, E (Laboratory 2) and N3 (Laboratory 3), with various detection methods. Only N1 and N2 genes resulted stable at the storage T of -20°C with a calculated uncertainty of 30.3 and 34.9% and a shelf-life of 5.1 and 4.5 days (uncertainty of 20%). Multiple factors play a role in the stability of samples, as detection method and sampled wastewater quality. Nonetheless, the outcome of the study represents a scientific evidence to support the transport conditions (4°C) chosen for EU wastewater surveillance and it highlights the importance of stability testing of environmental samples to determine the short-term analytical uncertainty.

TAVAZZI Simona;  CACCIATORI Caterina;  COMERO Sara;  FATTA-KASSINOS Despo;  KARAOLIA Popi;  IAKOVIDES Iakovos;  LOUTSIOU Panagiota;  GUTIERREZ-AGUIRRE Ion;  LENGAR Ziva;  BAJDE Irena;  TENSON Tannel;  KISAND Veljo;  LAAS Peeter;  PANKSEP Kristel;  TAMMERT Helen;  MARIANI Giulio;  SKEJO Helle;  GAWLIK Bernd; 

2023-03-13

ELSEVIER SCI LTD

JRC129775

2213-2929 (online),   

https://www.sciencedirect.com/science/article/pii/S2213343723003627,    https://publications.jrc.ec.europa.eu/repository/handle/JRC129775,   

10.1016/j.jece.2023.109623 (online),