Machines have been out and about on the Hibiscus Coast taking sewage samples and analysing them to see whether the Covid-19 virus is present.
The process is part of the Institute of Environmental Science and Research’s (ESR) wastewater testing that followed the most recent community cases and lockdown.
Samples taken in Whangaparāoa last month, as well as from other parts of Auckland and centres around the North Island, all returned negative.
The wastewater testing project is led by two ESR scientists – Dr Joanne Hewitt, head of the organisation’s environmental virology laboratory, and Dr Brent Gilpin.
Dr Gilpin says Whangaparāoa was included because samples were already being collected as part of normal operations in the area and it was a good opportunity to test a few more areas as part of the increased sampling that week.
“We are not planning on doing it routinely, but it demonstrates we can do smaller areas if we need to,” he says.
Dr Hewitt says while most of the samples were pumped automatically from large wastewater pipes, the ones taken in Whangaparāoa are known as “grab samples”, taken directly from manholes.
Rather than continue to do it this way, ESR may try different approaches in future, such as using passive samplers that can capture viruses from wastewater as it passes through it. These could be rapidly deployed at locations across the sewage network. The ESR website says that while it is theoretically possible to detect a single person shedding the virus from wastewater, that is unlikely in practice. It says that the test appears to be “sensitive enough to discover approximately 10 cases in an area of 100,000 people”.
Scientists believe this research is going to be useful for other viruses longer-term.
According to ESR’s website, wastewater epidemiology is a burgeoning area worldwide.
“Illicit drugs and infectious viruses are just two of the possible areas that wastewater analysis may allow us to understand. The smart toilet of the future may analyse what you deposit in your toilet to help with personal wellbeing and health.”
Initial work on the Covid-19 wastewater testing project was funded by the Ministry of Business Innovation and Employment’s Covid-19 Innovation Acceleration Fund, with the Ministry of Health funding further application of the work as part of New Zealand’s Covid-19 response.