Jarrod Gilbert: Wastewater testing gives accurate picture of drug use in New Zealand

Researchers test wastewater samples from Covid-19 managed isolation facilities. Wastewater testing has also revealed use of illicit drugs in New Zealand. Photo / Dom Thomas

OPINION:

One day, a few years back, someone came up with the kooky idea to regularly test the wastewater in New Zealand for illicit drugs. That person deserves a medal.

We now have an accurate picture of drug use in New Zealand - where and what drugs are being consumed. We can also track consumption trends over time.

This is not just a curiosity, this science from the sewers has a range of important policy implications.

New Zealand's drug profile is unusual, we favour methamphetamine over cocaine, despite meth being more damaging and cocaine being far more common around the world. Yet we have turned our noses up at opioids; the problematic use of which has been ravaging much of the world for years.

Dodging the opioid bullet may give us some cause for celebration; scores of deaths are linked to opioids in other countries. But our use of methamphetamine is a deeply troubling love affair.

While meth is used by an extremely small percentage of the population, the people who use it use it a lot. And many of them invariably find trouble. Those of us who work in crime – and those in health – will be aware of the often crippling effects of the drug. It might not immediately kill people like opioids have the tendency to do, but it can be a very swift wrecker of lives.

But there might be, just might be, some good news. The overall amount of meth being consumed has been trending down. Some of this may be the impacts of Covid – like legitimate business, the drug trade is impacted by lockdowns and import disruptions – but the trendline was dropping pre-Covid, too.

Many in the police point to a number of impressive drug busts contributing to this trend, but the changes in price levels indicate an oversupply at times, and basic economics suggests when there is demand, supply will follow.

But even if it is simply the lockdowns that have temporally stopped people consuming the drug, it's at least possible some will move away from it permanently having enjoyed the break.

But just how much of this reduction relates to Covid will eventually become clear when the worst of the pandemic is behind us, and that's the key to this wastewater testing. We have precise measures to tell us exactly what is happening at any given time. If we were to have a large campaign against meth, for example, we will be able to track its success or otherwise.

Drugs seized by police, along with firearms and cash, in Flat Bush and Otahuhu. Wastewater testing now provides a picture of where drugs are being consumed. Photo / NZH

Although cannabis is currently only tested at a small number of sites, if last year's legalisation referendum had gone differently, this would have been a perfect tool for measuring how the law change affected cannabis use; and test the rhetoric and assumptions made that legalisation would increase use of the drug.

The precise nature of the testing means we no longer have to base our knowledge of drug market around assumptions. And for the police this is significant. Priorities used to be based on the best guesses of cops using street-level intelligence. Wastewater testing proved just how seriously awry those assumptions often were, and therefore make more targeted enforcement a viable tool.

Without testing, we would never have known how close MDMA (ecstasy) came to overtaking meth in the overall quantity used in this country early last year. Before the start of the pandemic it looked as though the drug was on track to be more heavily used than methamphetamine, but use has fallen away again in 2021. We know this overall consumption stems from a higher number of people actually using MDMA. Where it's not unusual for a heavy meth addict to go through multiple grams of the drug a week, MDMA tends to be used only sporadically.

Although you won't see this is view in any government policy documents, based on health and social harms, I'd happily see ecstasy become the country's drug of choice over methamphetamine.

And seemingly so does much of the South Island, where overall MDMA consumption tends to outstrip that of methamphetamine. On my reading of the data, there appears to be spikes in Canterbury and Southern regions during the big university orientations and end-of-year celebrations. If that's so, it gives us the opportunity to target health and education efforts at specific groups at specific times.

But wastewater testing has potential that goes far beyond snitching on the nation's drug use. It has of course come into its own this year as a way of testing for undetected Covid-19 in the population, and may one day be used to test for other health-related measures, like the biomarkers of certain cancers and other diseases.

Whoever it was that convinced the Government that doing wastewater drug testing was a good idea, gained the funding to achieve something that is long-term and not directly related to enforcement or rehabilitation, and gained the goodwill of local councils that collect it has done the country a huge favour.

• Dr Jarrod Gilbert is the director of criminal justice at the University of Canterbury.