Sewage tested for Covid-19 to help monitor spread

Sewage is being tested for traces of Covid-19 in a trial aimed at helping monitor the spread of coronavirus in Scotland.

As part of the trial, samples from waste water at treatment works in each of the 14 NHS Scotland health board areas will be analysed by Scottish Environment Protection Agency (Sepa) scientists.

They are building on exploratory work started by Scottish Water and academic partners from Edinburgh University’s Roslin Institute to monitor the levels of fragments of Covid-19 ribonucleic acid (RNA) in waste water.

Experts hope the data could help understand trends in the prevalence and distribution of the virus in Scotland, in combination with community testing and hospital admissions data.

Sepa chief executive Terry A’Hearn said: “As one of the first European Environmental Protection Agencies to do so, we’re in the early stages of this exploratory work to trace the presence of coronavirus RNA in Scotland’s waste water.

“Our expertise in designing and implementing monitoring networks, coupled with our scientific capabilities, meant that we were able to get up and running quickly with the support of our partners. We believe we are one of the first agencies in Europe to begin this work.

“Our hope is that our analysis could provide useful data in Scotland’s efforts to trace the virus.”

Sepa estimates the samples will represent waste water from between 40% and 50% of the Scottish population.

The project has the backing of the Scottish Government and Health Protection Scotland.

The first waste water samples from eight health board areas are now being analysed in Sepa’s Lanarkshire Angus Smith laboratories.

The World Health Organisation has said there is currently no evidence that coronavirus has been transmitted via sewerage systems.

Dr Alexander Corbishley, of the Roslin Institute, said: “Detecting viral genetic material in waste water is relatively easy; however, the challenge is measuring how much genetic material is present accurately and relating that to disease levels in the community.”

Sepa said funding from the Centre of Expertise for Waters (Crew), which is supported by the Scottish Government, has allowed scientists in Scotland to work with academic colleagues across the UK to keep pace with international developments in the rapidly expanding field of wastewater epidemiology.

Environment secretary Roseanna Cunningham said: “The Covid-19 pandemic has been an unprecedented global crisis which has fundamentally affected us all.

“There has of course been much research work carried out globally to better monitor, assess and understand the virus.

“Such work is crucial to ensure our recovery and I welcome this important project being undertaken by Sepa, Scottish Water, academia and other partners to monitor the prevalence of the virus across the Scottish population.”