Last year, 31 types of illegal drugs, including methamphetamine, synthetic cannabinoids, and ketamine, were detected in wastewater across the country. The Ministry of Food and Drug Safety expanded its analysis from a maximum of 22 substances to 243, revealing the use of new drugs and so-called 'club drugs' that had previously gone undetected.
On July 24, the Ministry announced the results of the '2025 Illegal Drug Usage Survey.' The analysis was conducted on wastewater samples collected from 34 sewage treatment plants across 17 cities and provinces, as well as from densely populated areas such as Yongsan in Seoul, Incheon, Gwangju, and Jeonnam. The upper drainage basin refers to an intermediate collection area where wastewater from various regions converges before entering treatment plants.
The survey found 31 types of illegal drugs, including methamphetamine, and 25 types of medical narcotics, such as zolpidem, in the wastewater samples. Among the illegal drugs, 28 were classified as controlled substances under the Narcotics Control Act, while three were temporary narcotics. Notably, synthetic cannabinoids accounted for the largest share, with 21 types detected.
A significant aspect of this survey was the expanded scope of analysis. Since last year, the Ministry has increased the number of detectable drugs to 243 and broadened the survey methodology from focusing solely on sewage treatment plants to include upper drainage basins and specific densely populated areas. As a result, the number of detected illegal drugs rose sharply compared to the previous year, which recorded only seven types.
Methamphetamine was found at all survey sites. The estimated daily usage per 1,000 residents at sewage treatment plants was 85 mg, which is lower than levels in the United States (2,109 mg), Australia (1,518 mg), and the Czech Republic (1,175 mg). However, when adjusted for population, it suggests that approximately one in every 10,000 people is using methamphetamine, indicating a widespread issue nationwide.
By sampling location, 11 types of illegal drugs were confirmed at sewage treatment plants, 18 types in upper drainage basins, and eight types in densely populated areas. Notably, during the Halloween period last October, wastewater collected near entertainment venues in Yongsan revealed multiple club drugs, including cocaine, MDMA (ecstasy), and ketamine. These substances were not detected in general sewage treatment plants or upper drainage basins.
Considering that only four types of drugs, including club drugs, were detected during weekend surveys in the same area, it suggests that drug usage patterns can vary significantly depending on specific times and locations. There is a possibility that drug distribution and usage surged during events attracting foreign visitors and young people.
Based on the survey results, the Ministry plans to expand its monitoring scope. Next year, the number of upper drainage basin survey sites will increase from three to six, and the number of densely populated area surveys will rise from one to three. If illegal drugs are detected during the survey process, the Ministry will promptly provide information to law enforcement and local governments for enforcement actions.
Additionally, substances suspected to be new drugs will undergo further analysis for rapid classification as temporary narcotics. A Ministry official stated, "Wastewater-based epidemiological surveys are a means to quickly identify regional drug usage trends," adding that they aim to enhance the utility of these findings for enforcement and policy development.
On July 24, the Ministry announced the results of the '2025 Illegal Drug Usage Survey.' The analysis was conducted on wastewater samples collected from 34 sewage treatment plants across 17 cities and provinces, as well as from densely populated areas such as Yongsan in Seoul, Incheon, Gwangju, and Jeonnam. The upper drainage basin refers to an intermediate collection area where wastewater from various regions converges before entering treatment plants.
The survey found 31 types of illegal drugs, including methamphetamine, and 25 types of medical narcotics, such as zolpidem, in the wastewater samples. Among the illegal drugs, 28 were classified as controlled substances under the Narcotics Control Act, while three were temporary narcotics. Notably, synthetic cannabinoids accounted for the largest share, with 21 types detected.
A significant aspect of this survey was the expanded scope of analysis. Since last year, the Ministry has increased the number of detectable drugs to 243 and broadened the survey methodology from focusing solely on sewage treatment plants to include upper drainage basins and specific densely populated areas. As a result, the number of detected illegal drugs rose sharply compared to the previous year, which recorded only seven types.
Methamphetamine was found at all survey sites. The estimated daily usage per 1,000 residents at sewage treatment plants was 85 mg, which is lower than levels in the United States (2,109 mg), Australia (1,518 mg), and the Czech Republic (1,175 mg). However, when adjusted for population, it suggests that approximately one in every 10,000 people is using methamphetamine, indicating a widespread issue nationwide.
By sampling location, 11 types of illegal drugs were confirmed at sewage treatment plants, 18 types in upper drainage basins, and eight types in densely populated areas. Notably, during the Halloween period last October, wastewater collected near entertainment venues in Yongsan revealed multiple club drugs, including cocaine, MDMA (ecstasy), and ketamine. These substances were not detected in general sewage treatment plants or upper drainage basins.
Considering that only four types of drugs, including club drugs, were detected during weekend surveys in the same area, it suggests that drug usage patterns can vary significantly depending on specific times and locations. There is a possibility that drug distribution and usage surged during events attracting foreign visitors and young people.
Based on the survey results, the Ministry plans to expand its monitoring scope. Next year, the number of upper drainage basin survey sites will increase from three to six, and the number of densely populated area surveys will rise from one to three. If illegal drugs are detected during the survey process, the Ministry will promptly provide information to law enforcement and local governments for enforcement actions.
Additionally, substances suspected to be new drugs will undergo further analysis for rapid classification as temporary narcotics. A Ministry official stated, "Wastewater-based epidemiological surveys are a means to quickly identify regional drug usage trends," adding that they aim to enhance the utility of these findings for enforcement and policy development.
* This article has been translated by AI.
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