Technology to test Dublin wastewater for Covid presence adapted for illegal drugs

UCD scientists asked by HSE to analyse capital’s sewage for wide range of narcotics

Ringsend Wastewater Treatment Works: water there is being tested for presence of narcotics used by people living in Dublin. Photograph: Alan Betson
Ringsend Wastewater Treatment Works: water there is being tested for presence of narcotics used by people living in Dublin. Photograph: Alan Betson

Technology deployed during the pandemic to test for Covid-19 in the country’s waste water is now being used to detect and analyse illegal drug use in Dublin at the request of the Health Service Executive (HSE).

Scientists in UCD began testing wastewater for illegal narcotics about 18 months ago to determine the extent of their use in the population and to detect the presence of new designer drugs.

The first results were published earlier this year in a study comparing crack cocaine use in 13 EU cities. The wastewater analysis showed the prevalence of crack use in Dublin is broadly in line with most other cities examined but significantly less than Amsterdam and Antwerp.

UCD first started testing wastewater for the prevalence of Sars-CoV-2 in June 2020 at the request of the HSE. “Then they contacted me and asked, ‘Can you also look for drugs?’,” said Wim Meijer, professor of microbiology at UCD.

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Compound detection

“As you go to the bathroom you either pee out or poop out, or both, [these substances],” Prof Meijer said. “That gets into the sewage system, eventually finds its way to a wastewater treatment system where everything is collected. You can then take this effluent and analyse it for compounds.”

Scientists use a process called liquid chromatography mass spectrometry to test waste for compounds indicating the presence of drugs, Prof Meijer said. His laboratory can detect compounds linked to heroin, cocaine, cannabis, ketamine, methamphetamines and others.

Wastewater drug testing is already available in many other EU countries. It is considered a far better barometer of drug trends compared to surveys, where people may be reluctant to tell the truth about their drug use.

“It allows you to see what’s going in a population or if there are new drugs coming in,” said the professor. It can even be used to determine what days of the week people are most likely to use drugs, he said.

Environmental problems

The system can also be used to test the levels of pharmaceutical drugs in wastewater. Unlike illegal narcotics, some of drugs that contain biologically active compounds may cause environmental problems if present in large enough quantities.

It can also be used to determine which drugs are popular in which areas. “For example, I’m from the Netherlands and it was found ketamine was much more popular in rural areas than in big cities. So you needed a different type of approach,” said Prof Meijer.

“It can be deployed on various scales, in our case we are looking at an entire city. But you could use it to look at something like a prison,” Prof Meijer said.

“But there is no chance of it being used to determine drug use at a household or individual level,” he said.

“We are sampling the Ringsend treatment plant in Dublin, which serves 1.9 million people in the greater Dublin area. There is absolutely no way we can say, for example, ‘John Smith is using cocaine again’.”

Conor Gallagher

Conor Gallagher

Conor Gallagher is Crime and Security Correspondent of The Irish Times