A wastewater-based epidemiological study of licit and illicit drugs among schoolchildren and students in Slovenia
Abuse of illicit and licit drugs creates a huge social and economic burden in terms of poor health and increased crime. According to a 2017 report on the drug situation in the Republic of Slovenia, 26% of children and youth (15-16 year) had used a drug at some point in their lives. It also reports that 14% of young people (15 year) drink alcohol on a weekly basis and 55.1% (15-17 year) smoke tobacco on a daily basis. These are disturbing statistics especially considering that the health consequences of substance abuse are highest among young people and that drug surveys generally underestimate the number of users. A new approach called wastewater-based epidemiology (WBE) is a promising alternative to survey methods for estimating community drug consumption. WBE is based on accurate chemical analysis and quantification of human metabolic excretion products (biomarkers) of illicit and licit drugs. This approach provides spatial and temporal data as well as objective estimates of drug use. The aim of this study is to investigate drug consumption trends in primary and secondary schools and centres for higher education using WBE and is the first study of its kind in Europe.
Daily composite sewage samples were collected from six urban and six rural educational establishments from five Slovenian regions. After filtration, the target urinary biomarkers of drugs and tobacco were extracted by solid-phase extraction (Oasis MCX and Oasis HLB cartridges). After enrichment of analytes from samples, wastewater extracts were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the levels of biomarkers of six illicit drugs (cocaine, heroin, amphetamine, methamphetamine, ecstasy and cannabis) and four licit drugs (tobacco, alcohol codeine and methadone) were determined. For determination of biomarkers for alcohol consumption, wastewater samples were filtered and injected directly into to the LC. Based on determined concentrations of biomarker and wastewater flow, daily mass loads were calculated and normalized to number of students. Drug consumption was estimated using the method of Zuccato et al.
A comparison of drug consumption based on weighted student population data according to geographical location (urban vs. rural) and educational level (primary, secondary, higher education) will be presented and compared with data from the European School Survey Project on Alcohol and Other Drugs (ESPAD) and the Health Behaviour in School-Aged Children (HBSC) project.
Wastewater analysis provides complementary data on drug use. This is the first time this method has been used in Slovenia and will provide important information on drug use among Slovenian schoolchildren and students.