Saturday 27th June, 2020 Water Blog

THERE IS IMPORTANT INFORMATION IN SEWAGE

Back in April when I started writing a Water Blog, I talked about wastewater epidemiology and the potential for this in monitoring for COVID-19. We study wastewater for the occurrence of chemicals and I believe that, in the absence of biomonitoring studies, sewage is an excellent sample to provide information about a populations exposure to chemicals – and also disease.

In the last week there have been reports that an Italian sewage study suggests Covid-19 was in Italy in December. An Irish Times report[1] highlights that samples taken in Milan and Turin showed the presence of virus before the first case was reported in China.  The Italian National Institute of Health co-led the research into sewage surveillance. This is where sewage is collected before it enters the treatment plant and it is analysed for the occurrence of SARS-Cov-2.  France also found a similar result of a December occurrence of SARS-Cov-2. There are many groups around the world that are using this approach now, to determine if it works to detect the presence of the disease in a particular location.  More importantly, if it does work, scientists are looking to see, if the approach can be used in a monitoring programme to indicate a resurgence of the disease – or a second wave.  It is great to see some of this work starting in Ireland also[2].  However, time is of the essence.  We need to have a nationwide approach to monitoring, driven by the health authorities, up and running very soon.

With the opening of the country on Monday next (29^th) we will have people like myself, eager to move around Ireland.  We need to be able to quickly tell if this movement is leading to cases of COVID-19, before these cases start a spread. Indeed, if there are asymptomatic cases, this approach should be able to highlight a risk in a particular location before a significant spread occurs.

What would it take to have a nationwide programme of sewage monitoring?

We need all potential stakeholders: industry who can take samples at high enough density and frequency and those that can analyse them; scientists to monitor for virus occurrence and maybe changes in the virus, scientists to analyse the data and assess trends, engineers to assess the risk to workers and so much more.

But critically, a significant sampling plan that can provide sample to answer in a short timeframe – days not weeks is needed, so that the country has information to be able to make decisions fast. This should form part of an overall COVID-19 management strategy.

[1] https://www.irishtimes.com/news/world/europe/italian-sewage-study-suggests-covid-19-was-there-in-december-1.4284597

[2] https://www.rte.ie/news/ireland/2020/0609/1146441-raw-sewage-covid/