Norovirus, ammonia and orthophosphate in wastewater samples collected from across England 2021 - 2022

notPlanned

The samples were originally received by Environment Agency, and were taken by the companies who owned the assets. The samples were spiked with an extraneous control virus (phi6) to act as a quality control before the viruses were concentrated by ammonium sulphate precipitation and nucleic acid extraction using the NucliSENS reagents with Kingfisher robot. The nucleic acids were first used to quantify SARS-CoV-2 in the samples before being stored at -80°C. The norovirus data were generated from the nucleic acid extracts by the Environment Agency at Starcross laboratory based in Exeter on behalf of Cefas. Norovirus concentrations were measured using a duplex RT-qPCR duplex assay. The duplex assay measures norovirus genogroup I (GI) and genogroup II (GII) separately. Norovirus data were converted from genome copies per reaction to genome copies per litre, and then further normalised for flow and population size for the sewershed. Flow was estimated using ammonia and orthophosphate concentrations for each sample. Human population was estimated using ONS (Office of National Statistics)** **mid-2019 estimates based on data from the 2011 census. Ammonia and orthophosphate concentrations (mg/l) were measured in the samples according to the Environment Agency’s in-house methods. These methods were based on the relevant Standing Committee of Analysts methods (SCA).