Traces of coronavirus acid detected in waste water across Scotland

SCIENTISTS at the Scottish Environment Protection Agency’s (Sepa) have pinpointed fragments of coronavirus’ ribonucleic acid (RNA) in local waste water samples across the country.

Sepa was among the first European agencies to begin this exploratory work back in May, with the backing of Scottish Government and Public Health Scotland (PHS), alongside Scottish Water, CREW (Centre of expertise for Waters) and academic partners from the University of Edinburgh’s Roslin Institute and Heriot Watt University.

The aim was to detect fragments of the virus’ RNA – a genetic footprint which can be measured in waste water even after the virus has begun to break down.

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

Analysis on samples from across Scotland has now identified traces in waste water from 12 health board areas.

Areas with positive RNA findings are consistent with the areas known to have confirmed Covid-19 cases.

One such example is Aberdeen, where Sepa’s analysis demonstrates how the prevalence of the virus in waste water samples is mirroring cases in the population. At the beginning of August, Sepa analysed a sample from the Aberdeen area which was positive for Covid-19 RNA. This was consistent with an increase in positive cases in the area.

On Sepa’s request Scottish Water increased the sampling rate to four times a week to provide more information, and over the following three weeks there was a gradual decline to below the level that concentrations can be detected with sufficient accuracy. Sample results remained at the same level until the end of September when they began to rise again, reflecting PHS data on known cases.

Testing is conducted on incoming waste water samples collected by Scottish Water and its operators at 28 public waste water treatment works across the country, covering all 14 NHS Scotland health board areas. Most locations are tested weekly, but this can be increased when local outbreaks are apparent.

In combination with community testing, the results help scientists understand the prevalence and distribution of the virus.

Terry A’Hearn, Sepa chief executive, said: "As Scotland’s environmental watchdog and as a public agency, we remain proud to be playing our part in the national effort to combat coronavirus.

"We’ve received support from across the public sector, agencies and institutions – including a donation of specialist kit from Science and Advice for Scottish Agriculture – demonstrating how Scotland is coming together to find ways of tackling this virus."

Environment Secretary Roseanna Cunningham said: "Sepa and Scottish Water have translated this experimental programme into a comprehensive, Scotland-wide monitoring network.

"The early data is already providing our public health experts with new information, which complements the wider population testing programme to give a more robust picture of the prevalence of Covid disease in Scotland."

Sepa has made data available for all samples analysed at https://informatics.sepa.org.uk/RNAmonitoring/ .