Law Enforcement May Analyze Your Sewage For Drugs
Researchers have discovered that what you flush down the toilet
can reveal your deepest secrets.
Law enforcement agencies in China are already analyzing what you flush
to discover if you might be abusing prescription and illegal drugs.
Scientists call this "wastewater-based epidemiology".
By mid 2000s, studies were looking for metabolites,
traces of drugs broken down in the body and excreted through urine.
By the mid 2010s, this research was mainstream.
So far, outside China, this has been limited to community-wide studies.
What drugs are used by citizens of a city, or students at a university,
and when do they use them?
Many of these studies have simply verified expectations.
College students use prescription medicines as "smart drugs",
especially around exam times.
People in Medellín, Colombia use a lot of cocaine.
Cocaine use around the world goes up over the weekend.
With cautious quantitative analysis, researchers found
that they could put useful numbers on estimates.
For example, in Lausanne, Switzerland they measured morphine metabolites
in the wastewater stream and compared that to what was known to have
been prescribed for medical reasons.
They estimated a city-wide daily consumption of 13 grams of heroin.
Then they compared that to transactions by known suppliers,
to estimate how many heroin dealers remained active.
Sludge digestion tanks at New York City's
Wards Island Wastewater Treatment Plant.
People May Lie, But Their Urine Doesn't
Illicit drug use is, by definition, illegal.
On top of that, there is a social stigma.
Even if you don't care about the legal issues,
you will likely give misleading or inaccurate answers.
The truth is hidden — in your sewage.
Meanwhile the European Monitoring Centre for Drugs and Drug Addiction
is trying to collate information on drug use across the continent
in order to better respond to drug use.
80-90% of the population in western Europe is connected to
primary sewage treatment systems, versus only 40-65% in eastern Europe.
In cities with high coverage of sewage treatment, sampling at treatment plant
inlets provides a "diluted and pooled community urine sample",
to quote one of the studies.
Urine Reveals Drug Use In 11 Countries Across Europe
A group of scientists from across Europe published a
study of wastewater in 19 cities in 11 countries.
They collected sewage samples around the clock during one week.
They then looked for urinary biomarkers of several illicit drugs,
discovering which drugs were used more in which cities.
The samples were collected from the inlets of 21 sewage treatment plants
in those 19 cities.
The samples were collected through the day,
so they were all 24-hour composite samples.
The cities were:
Belgium: Antwerp and Brussels,
Czech Republic: Budweis,
Finland: Helsinki and Turku,
Netherlands: Amsterdam, Eindhoven, and Utrecht,
Spain: Barcelona, Castellón, Santiago de Compostela, and Valencia,
Sweden: Stockholm and Umeå, and
Comparing illicit drug use in 19 European cities
through sewage analysis
The samples were sent through liquid chromatography and mass spectrometry.
The methods and equipment were capable of measuring at ng/L concentrations.
They were looking for biomarkers of cocaine,
MDMA or ecstasy,
They found that cocaine was a drug of the
Netherlands, Spain, and the UK, and not of the east and north.
The highest estimated per-capita cocaine use was in Antwerp, and then
in decreasing order, Amsterdam, Valencia, Eindhoven, Barcelona,
London, Castellón, and Utrect.
Those cities consumed 987-1998 mg/day/1000 inhabitants.
The lowest cocaine consumption was in Budweis, Zagreb, Helsinki, Turku,
Oslo, Stockholm, and Umeå, just 2-145 mg/day/1000 inhabitants.
For those countries with multiple cities in the study,
the larger cities had higher per-capita cocaine use.
More in Helsinki than Turku, more in Stockholm than Umeå, and so on.
MDMA or Ecstasy was most common
in the Netherlands and the UK, with the highest per-capita levels
in Amsterdam, Utrecht, and Eindhoven.
It wasn't detected at all in Castellón, Umeå, Stockholm, or Oslo.
MDMA in Europe is believed to be mostly manufactured in the Netherlands
and used in the UK and Czech Republic.
The amounts found in this study go along with that
(with Budweis being a small city with lower use).
Methamphetamine wasn't detected in Zagreb, Paris,
Castellón, Amsterdam, Eindhoven, and Utrecht.
But it was present in high levels (300-376 mg/day/1000 inhabitants)
in Helsinki and Turku, and moderately high levels in Oslo and Budweis.
These results also agree with figures from law enforcement.
Cannabis biomarkers were highest in Amsterdam,
192 mg THC per day per 1000 inhabitants.
Other cities were in the range of 14 to 124 mg/day/1000 inhabitants.
Cannabis is thought to be the most popular illicit drug in Europe,
used by around 7% of the population aged 15 to 64.
Dutch drug law allows its use by all citizens over 18,
hence the high level in Amsterdam's sewage.
Unsurprisingly, the day-to-day variation for multiple drugs peaked on
Saturday and Sunday (after Friday night and Saturday night),
and was at minimum levels Tuesday through Thursday.
The blacklight illumination for the toilet at the Homegrown Fantasy
coffeeshop in Amsterdam frustrates injection drug abuse.
Public toilets in the Chungking Mansions in Hong Kong.
study of drug use in Hong Kong
collected raw wastewater from the city's largest treatment plant,
sampling the diluted urine of about 3.5 million people.
They found that ketamine was the most prevalent drug
in Hong Kong, with an estimated consumption (and then excretion)
of 1400 to 1600 mg/day/1000 inhabitants.
That is very different from other prominent world cities,
but ketamine is relatively more available, cheaper, and higher and more
consistent in purity in Hong Kong.
The city is very densely settled, so the ease of sociably sharing
a finely powdered substance of consistent purity may also factor into
ketamine's local popularity.
Methamphetamine was the next most common drug in Hong Kong's sewage,
at 180-200 mg/day/1000 people, and then cocaine at 160-180 mg/day/1000 people.
They looked for MDMA or ecstasy,
but surprisingly, they didn't find it.
They found clear patterns not just day by day, but also hour by hour.
There were two daily peaks of drug excretion, one in the morning
between 7 AM and 11 AM, and another in the evening about 7 PM to midnight.
Estimating daily and diurnal variations of illicit drug use in Hong Kong:
A pilot study of using wastewater analysis in an Asian metropolitan city
study in Colombia
collected samples for 24 hours in Bogota and Medellín.
The sewage was from about 2.5 million inhabitants in Bogota and
600,000 in Medellín.
They looked for metabolites of cocaine, cannabis, amphetamine,
methamphetamine, MDMA, heroin, and ketamine.
Cocaine dominated the results.
They estimated cocaine consumption up to 162 mg/day/1000 inhabitants
There was relatively little ketamine use, although it is relatively new
It is used as an adulterant in MDMA and a synthetic hallucinogen
which is "considered as the world's most expensive illicit drug
used by the upper-class party scene."
Estimation of illicit drug use in the main cities of Colombia
by means of urban wastewater analysis
China Tests Sewage For Drugs
An article in Nature in July 2018 reported that
"dozens of cities across China" were already using this.
It quotes Li Xiqing, an environmental chemist at Peking University
in Beijing who is working with police.
"Li says Zhongshan police have already used this technique to help
track down and arrest a drug manufacturer.
He says a handful of cities are planning to use data from waste water
to set targets for police arrests of drug users, some as early as
That is, in 2019.
"Li says the central and local governments will invest at least
10 million yuan (US$1.5 million) in wastewater-based epidemiology
by the end of the year."
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