Higher levels of opioids and meth found in Vancouver waste water: StatsCan
Credit to Author: Cheryl Chan| Date: Wed, 28 Aug 2019 00:47:14 +0000
Metro Vancouver has higher-than-average levels of opioids and methamphetamine in its waste-water system compared with other Canadian cities, according to a new Statistics Canada study analyzing cannabis and drug use in the country based on what Canadians flush down their toilets.
In contrast, Vancouver reported less-than-average levels of cannabis in sewage, casting doubt on the city’s reputation as Canada’s cannabis capital.
The pilot project uses a new technique called waste-water epidemiology, which has been used in Europe since 2007 to gauge the consumption of different types of drugs in urban areas. It collected and tested municipal waste-water samples from 14 treatment plants in five major urban centres between March 2018 and February 2019. Samples were taken every half-hour for a week per month, and were analyzed by researchers at McGill University in Montreal.
The test areas serve 8.4 million residents, about 20 per cent of Canada’s population — the largest conducted in North America in terms of population covered, said StatsCan.
“Clear differences … emerged in the drug profiles of the different pilot-test cities,” concluded the report. “Cannabis use was higher in Montreal and Halifax, but Vancouver and Edmonton tended to have higher per-person use of methamphetamine.”
The findings also suggest some drug use could follow seasonal patterns, but the study noted the pilot project only covered a year, and further study is needed to determine whether this is a regular pattern.
The study found that opioid use measured through morphine was highest in Vancouver, followed by Edmonton, Halifax and Toronto. Opioids measured through codeine was highest in Edmonton, then Halifax, Vancouver and Toronto.
Montreal had the lowest level in both morphine and codeine loads.
The report notes Canada is the second-largest consumer of opioids per capita in the world, and is grappling with a growing crisis caused by illicit use or prescription-related harms.
It compared waste-water results with the differences in provincial health-care spending to try to gauge how much of the opioids found in waste water were prescribed within the health-care system. B.C.’s relatively average spending doesn’t explain the high morphine levels detected in Vancouver’s waste water, said the report. It’s a similar case in Edmonton, where slightly above-average spending for morphine appears to contradict Edmonton’s high morphine levels in waste water.
“The relatively high morphine loads observed in Vancouver, Edmonton, and to a lesser extent in Halifax, may thus indicate some level of non-prescribed opioid use,” said the report.
For meth, levels were highest in Edmonton and Vancouver — about 3.7 times higher than Toronto and Montreal. Levels of the illicit stimulant were particularly low in Halifax, which has levels six times lower than in Toronto, the next-lowest city.
Cocaine use, measured through a compound called benzoylecgonine, was more evenly distributed among cities, although Vancouver recorded the highest average load per capita in Canada. Results suggest slightly higher cocaine use in the summer, dipping in the fall, before peaking in December.
For cannabis, researchers analyzed quantities of a compound called THC-COOH, which is produced by the body after cannabis is metabolized. Halifax, which recorded the highest level of THC-COOH, has three times the level found in Vancouver, which was second-lowest next to Edmonton. The study also recorded large spikes of the compound in waste water in May, June and December, but it’s uncertain whether these spikes are due to changes in the amount of cannabis consumed, variations in waste-water flow rates or other factors.
Despite its limitations, the study’s findings show waste water has potential as a data source to measure total drug use at the city level, and can be used, along with other data, to estimate the total use of drugs in an anonymous way and could address under-reporting of use of illegal drugs like cocaine and meth.
The next phase of the research is to improve the precision of the new technique and to identify whether it can be applied in other areas such as infectious disease and environmental contaminants, said StatsCan.
The study took samples from untreated effluent.
Metro, which oversees the region’s waste-water treatment plants, said it doesn’t have specific data to determine how much of these substances are removed by the plants.