1. Comparison of data from WBE with other sources
A summary of findings
Been F., Lai F. Y., van Nuijs A. L. N., Covaci A.

2. Why would you want to compare?
“Realising the full potential of wastewater-based information will depend on integrating it into the existing set of epidemiological indicators“
EMCDDA Insights 22; Assessing illicit drugs in wastewater: advances in wastewater-based drug epidemiology, 2016 
“Realising the full potential of wastewater-based information will depend on integrating it into the existing set of epidemiological indicators“
EMCDDA Insights 22; Assessing illicit drugs in wastewater: advances in wastewater-based drug epidemiology, 2016 

3. Why would you want to compare?
Measuring drug use
General population surveys
Deaths & Mortality
Infectious diseases
Problem drug use
Treatment demand
Law enforcement
Wastewater-based epidemiology
Measuring drug use
General population surveys
Deaths & Mortality
Infectious diseases
Problem drug use
Treatment demand
Law enforcement
Wastewater-based epidemiology
WBE is only one piece of the puzzle

4. Complementarity Surveys and other indicators Wastewater analysis
Consumption
Consumers
Illicit drug loads
[Milligrams per day per 1000 inhabitants]
Prevalence
Treatment
Seizures …

5. International studies
European multi-city study

6. International studies
Cities across Europe
2011: 19 cities ….
2017: 50 cities
Illicit drug loads
[Milligrams per day per 1000 inhabitants]
Prevalence
At the time, the estimated illicit drug loads measured from wastewater analysis were compared to prevalence figures.
In particular using data which was derived from the European Drug Report of 2012 and 2013.

7. International studies
Cocaine
Findings
Wastewater: stable use
Other indicators: decline
2016
Wastewater: increased use
European drug report:
Increased availability (seizures)
Stable prevalence
Wastewater as an early warning of an upcoming surge in cocaine use?
Looking at cocaine as an example, in 2013 WBE showed that consumption was overall stable
Other indicators mentioned in the Eu Drug Report were on the other hand suggesting a decline. 3 years later, WBE results reported in the Eu Drug Report indicate that there had been an increase
This appears to be confirmed by an increased availability, based on seizures, yet prevalence estimates indicate that consumption has remained stable.
Looking at this data one might ask whether WBE (and seizures) are not suggesting a potential upcoming increase in COC use across europe

8. International studies
Alcohol
Wastewater
1 week, 2014, 20 cities
Comparisons WHO: Global Status Report on Alcohol and Health
Sales
Surveys

9. International studies
Alcohol
Findings
Wastewater: daily consumption higher for 11/20 cities compared to WHO
Cities might be different than entire countries
Longer sampling periods could potentially provide different results
Interestingly, comparison of WBE results about alcohol use and figures from the WHO show that actual consumption appears to be higher to current figures in 11/22 cities across the world.
However…

10. International studies
Alcohol
Findings
Correlation with illicit drug use (from wastewater analysis)

11. National studies Italy Wastewater: 1 week, 2011-2014, 17 cities
General population surveys (mail)
2010, 2012, 2014
NE, NW, Centre and S
Stratified, 18-24y/25-34y/35-64y
Last-month prevalence

12. National studies Italy Findings
Overall WBE and GPS gave similar results
Substance
GPS
[last month prevalence %]
WBE
[back-calculated consumption g/day 1000 inhab]
Cannabis (THC)
3.0
4.35 (THC)
Cocaine
0.43
0.78
Opioids
0.17
0.092 (Heroin)
Amphetamines
0.14
0.103 (MA + MDMA)
Time trends
Period
GPS
[last month prevalence %]
WBE
[back-calculated consumption g/day 1000 inhab]
Amphetamines: -86%
Opioids: -53%
Cannabis: -39%
Cocaine: -39%
MA + MDMA: -87%
Heroin: -29%
Cannabis: +3%
Cocaine: ND
Amphetamines: ND
Opioids: ND
Cannabis: +102%
MA + MDMA: ND
Heroin: ND
Cannabis:+48%

13. National studies Finland Wastewater Complementary data
1, week, 14 cities, 2012 and 2014
Almost 40% of Finnish population
Complementary data
DUID statistics
Seizures data
Market size estimates

14. National studies Finland Findings Amphetamine dominates
Confirmed increase by all indicators
Increased purity in recent years
Methamphetamine stable
MDMA marked increase (WBE and DUID)
Cocaine increasing popularity (all indicators)

15. Regional studies Mid-sized city – Switzerland Wastewater
Two samples per week every second week
15 months (October ’13 – December ’14)
Complementary data
GPS (prevalence)
Web-surveys (consumption habits)
Purity (forensic)
Surveys
Forensic analysis
Waste water
Estimate cannabis use

16. Regional studies Mid-sized city – Switzerland Estimates Model
Daily cannabis consumption [g.day inhab-1]
Number of users
Prevalence
(12 months)
Epidemiological data only
Estimate
8.1
11’830
6.2%
95% CI
7’078 – 16’860 %
Wastewater data only
17.2 -
Epidemiological and wastewater data
14.0
19010
9.4%
13’370 – 26’720 %
Model
Daily cannabis consumption [g.day inhab-1]
Number of users
Prevalence
(12 months)
Epidemiological data only
Estimate
8.1
11’830
6.2%
95% CI
7’078 – 16’860 %
Model
Daily cannabis consumption [g.day inhab-1]
Number of users
Prevalence
(12 months)
Epidemiological data only
Estimate
8.1
11’830
6.2%
95% CI
7’078 – 16’860 %
Wastewater data only
17.2 -

17. Conclusion
WBE appears to anticipate results from GPS and other indicators  Early warning
Provides more easily temporal and geographical information
If a sufficient number of samples is collected
Figures from other indicators are and remain vital

18. Conclusion Additional efforts are required
Beyond comparisons with prevalence
Develop interpretative frameworks including WBE and other indicators
Prevalence
Consumption habits
User types
Consumption estimates (WBE) …
Uncertainties
Inference approaches

19. Added value Corroborate/ confute Refine estimates Evaluate Policies
Hypotheses
Prevalence
Prevention programs
Trends
Users
Quantities
Market size

20. Thank you