Analysis: preliminary analysis puts the average daily consumption of the drug to be in the order of 100 milligrams per 1,000 people per day
By Seán McDermott and Patrice Behan, TU Dublin and Ciara McNamee, Forensic Science Ireland
Cocaine is naturally occurring in the Erythroxylon coca plant which has been used as a stimulant for over 5,000 years by chewing the leaves. Later, cocaine was extracted from the leaves of these plants and used in the medical field, for example as pain relief for toothaches.
The clandestine extraction process in the jungle areas of South America today involves moving from coca leaves to coca paste to cocaine base to cocaine powder. The process uses various easily available chemicals such as diesel, petrol sulphuric acid and sodium bicarbonate.
Cocaine in Ireland is mostly seen in two forms, either a crystalline powder or as a free base known as 'crack' cocaine. The powder form is routinely snorted, while 'crack' cocaine, formed by reacting the powder form with baking soda, is inhaled (smoked). Cocaine consumption in Ireland is considered to be amongst the highest in Europe and it is anecdotally available in every corner of Ireland.
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From RTÉ Radio 1's Drivetime, what wastewater samples tell us about cocaine use in Co Kildare
Cocaine use data is normally derived from Garda and Customs seizure data and also from surveys of drug use. The Health Research Board (HRB) conducts surveys and research around drug prevalence and treatment. Their Drug Treatment Demand report in 2023 detailed cocaine as the main problem drug, with 37.6% of all cases requiring treatment from cocaine use. In Europe, the European Union Drugs Agency reported in 2023 that cocaine was also the most common stimulant drug consumed, with trading and availability of cocaine at the highest level in history.
However, both of these methods can give an inaccurate picture of the actual situation on the ground. Another way of determining the use of cocaine in the community is by wastewater based epidemiology, an approach analysing wastewater to monitor drugs or pathogens in the population.
Victor Hugo wrote over 150 years ago that "the sewer is the conscience of the city". This is as true today as it was then. Sometimes what polite society does in private can be ultimately detected in the public sewers. Just like a urine test at a doctor’s office, an analysis of wastewater provides a measure of a community’s health and the substances it consumes.
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From RTÉ News, report by RTÉ Crime Correspondent Paul Reynolds on how cocaine use by the well-off is fuelling violent crime
Since 2011, a Europe-wide group SCORE has been analysing wastewater to estimate drug consumption within Europe. This project looks at results from 88 cities around Europe, which have applied a standardised approach to collate data on the consumption of drugs such as cocaine, amphetamine and cannabis. As of now, Ireland does not contribute data to this project
When a drug is ingested, it is often metabolized in the body before being excreted. These metabolites move through the body in the blood before being excreted in urine (most typically) and in faeces, ultimately ending up at the wastewater treatment plant.
Cocaine is metabolized in the body and the main breakdown product is benzoylecgonine (BZE). When excreted in urine, only a portion remains as cocaine, so the measurement of cocaine and/or its metabolites can be used to determine cocaine consumption in the community.
From Context, the incredible things sewage and wastewater can reveal about our lives
We can estimate cocaine use in the community from wastewater analysis, which involves a number of steps:
(i) Taking water samples from wastewater treatment plants
(ii) Analysing the water for cocaine (or the metabolite, BZE)
(iii) Getting the daily flow rate of water through the treatment plant
(iv) Getting some data on the number of people served by the treatment plant.
Using the above data, we can calculate the average amount of cocaine consumed per 1,000 people in the catchment area.
TU Dublin in association with Forensic Science Ireland and Uisce Eireann have recently joined forces to look at wastewater from two separate wastewater treatment plants in Co Kildare. In this pilot study, samples were taken from both locations over three weekdays in April/May 2024. The water samples were taken prior to entering the treatment plant (influent). The samples were taken as composite samples, meaning they were taken over a 24 hour period rather than at one specific time.
The analysis involves taking a 200ml of waste water, passing it through a sieve/trap which will allow the water through but retain certain chemicals such as the ones from cocaine consumption. The chemicals are then washed off the trap and analysed.
From Nicola Tallant's Crime World podcast, how cocaine use is changing the face of rural Ireland
The results of the analysis of the water samples show the presence of cocaine and BZE in both locations and on each of the sampling days. Initial preliminary estimates put the average daily consumption of cocaine to be in the order of 100 milligrams per 1,000 people per day
How does this compare to other locations within Europe? The European Union has undertaken an analysis of wastewater from a number of locations throughout Europe. The findings from 2023 show weekday mean values for Athens to be 137mg/1000people/day, Vilnius at 104mg/1000people/day, Helsinki at 189mg/1000people/day and Krakow at 65mg/1000people/day.
While these results may not come as a big surprise to many, it may be the beginning of a more systematic approach to estimating the use of drugs such as cocaine in locations throughout the country. The data can provide an early warning of emerging health threats to help inform localised public health interventions.
Dr Seán McDermott is a lecturer in the School of Chemical & BioPharmaceutical Sciences at TU Dublin. Dr Patrice Behan is Head of Chemical Sciences in the School of Chemical & BioPharmaceutical Sciences at TU Dublin. Ciara McNamee is a forensic scientist at Forensic Science Ireland
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The views expressed here are those of the author and do not represent or reflect the views of RTÉ
