Wastewater Reveals Hidden Opioid Crisis Trends
New Science Tracks Drug Use Beyond Traditional Data
Unconventional methods are surfacing crucial insights into the escalating opioid crisis, revealing patterns that traditional surveillance may miss. Groundbreaking research presented at a leading science conference highlights the power of analyzing wastewater to monitor drug consumption across entire populations.
Ancient Roots, Modern Peril
The long history of opium’s use for pain relief was detailed by Derryn Grant, a doctoral candidate at Imperial College London. She noted that even by the 11th to 13th centuries, the addictive nature of these substances was recognized, a concern that continues today with the emergence of potent synthetic opioids.
The development of heroin in 1874 and its subsequent marketing by Bayer as a purportedly non-addictive morphine alternative proved tragically misguided. While the UK began regulatory action in the late 19th century, the 1960s introduction of synthetic opioids like nitazenes has amplified public health challenges.
A Widening Gap in Care
Across the EU and UK, opioid-related fatalities continue to climb. In 2022, an estimated one million individuals in the EU were classified as high-risk opioid users. Opioids contributed to 76 percent of drug-related deaths in the EU, according to the European Monitoring Centre for Drugs and Drug Addiction. In England and Wales, synthetic opioids and other novel psychoactive substances have increasingly been cited in death certificates since 2017.
Grant expressed alarm at the concurrent decline in individuals seeking treatment for opioid addiction. This trend suggests a growing disconnect between the scale of the problem and the available resources dedicated to addressing it.
Rethinking Data Collection
Current monitoring in England and Wales relies on data that is acknowledged as incomplete and subjective. Grant pointed to limitations in coronial reports and the Crime Survey for England and Wales, arguing that the latter’s association of drug use with criminality fosters stigma and hinders objective data collection.
To overcome these obstacles, Grant introduced her work in wastewater-based epidemiology. This innovative technique analyzes traces of drugs and their byproducts excreted in urine, which are then collected at wastewater treatment facilities.
“This approach provides real-time, objective data on drug consumption, disease biomarkers and other indicators of public health.”
—Derryn Grant, Doctoral Candidate, Imperial College London
Wastewater as a Public Health Barometer
Grant‘s laboratory employed advanced liquid chromatography coupled with tandem mass spectrometry, incorporating stringent quality controls. The team focused on 6-monoacetylmorphine (6-MAM), a specific marker for heroin, alongside various synthetic opioid compounds. Their study analyzed over 800 samples from 17 treatment facilities, covering approximately 20 percent of England’s population.
Results indicated that heroin use, as inferred from 6-MAM levels, remained consistent throughout the week. This pattern aligns with heroin’s pharmacological profile, requiring frequent dosing to prevent withdrawal symptoms. Unlike drugs like MDMA or cocaine, which tend to peak on weekends, heroin metabolites showed less fluctuation.
A notable surge in heroin metabolites was observed in March and April 2022. Initially thought to be seasonal, this trend did not recur in subsequent years. Investigations into prescribing data revealed no corresponding increase in diamorphine prescriptions. Grant attributed the anomaly to pandemic-era changes in opioid substitution therapy, where patients received larger take-home methadone doses. As restrictions eased, prescription volumes returned to previous levels.
Spatial analysis did not reveal a clear link between wastewater plant catchment size and opioid residue concentration. Intriguingly, some Midlands areas showed higher heroin use than expected, contradicting national mortality data that indicated increased opioid deaths in coastal and northern regions. Grant suggested that differences in illicit heroin batch toxicity, autopsy thoroughness, or analytical practices might explain these discrepancies.
Further analysis using principal component analysis compared wastewater data with prescription records for methadone, its metabolite EDDP, and diamorphine. Strong correlations were found between methadone prescriptions and its presence in wastewater, with EDDP levels mirroring methadone, reinforcing the method’s reliability. Similarly, 6-MAM correlated with diamorphine prescriptions, though some signal likely originated from illicit heroin use. These findings underscore wastewater analysis’s potential for valuable insights into both therapeutic and non-medical opioid consumption.
Confronting the Synthetic Threat
Grant highlighted the significant risks posed by ultra-potent synthetic opioids such as fentanyl, carfentanil, and nitazenes. Fentanyl is approximately 50 times more potent than heroin, while carfentanil can be up to 3,400 times stronger. Nitazenes can be up to 500 times more potent than morphine, presenting formidable analytical challenges for detecting trace amounts in wastewater.
Despite growing concerns, few wastewater studies have quantified more than a few fentanyl analogues. Grant‘s team developed targeted liquid chromatography–mass spectrometry methods for fentanyls and nitazenes, enhancing detection sensitivity and reducing interference. Their fentanyl method could detect up to 12 analogues, and the nitazene method identified eight distinct compounds. They also optimized sample preparation, reducing required volumes and achieving a 500-fold concentration factor, enabling detection limits below 1 ng/L for fentanyls.
A critical aspect of their research involved assessing compound degradation. In raw wastewater stored at –20°C, analyte concentrations dropped by over 50 percent within five days. Even extracted samples saw levels fall below 60 percent after 25 days of storage. Grant stressed the importance of immediate sample processing and advised against repeated freeze–thaw cycles.
While acidification or pH alteration can improve stabilization, these methods may not suit all analytes. The team explored pre-acidified sampling bottles as a potential field solution but noted safety concerns and the need for specialist handling, limiting wider participation.
An enhanced transport and logistics partnership ensured faster sample delivery to the laboratory, often within hours of collection.
A Framework for the Future
Grant concluded that her research represents the most extensive longitudinal study of heroin use via wastewater monitoring in England. It established a methodological framework for correlating wastewater findings with prescribing patterns and pioneered targeted analytical methods for synthetic opioids in the UK.
The study also provided a detailed assessment of synthetic opioid stability in wastewater. Grant emphasized the necessity of a robust analytical infrastructure to track the evolving drug landscape and safeguard public health against the escalating threat of potent synthetic opioids.
These findings underscore the potential of wastewater-based epidemiology to bolster early warning systems and complement conventional monitoring strategies. According to the US Department of Health and Human Services, overdose deaths involving synthetic opioids (excluding methadone) increased by 11.4% between 2021 and 2022, highlighting the ongoing and evolving nature of this public health crisis (CDC, 2023).
