Evaluation of spatial and temporal changes in illicit drug use in the Taipei metropolitan area via wastewater-based epidemiology.

Taiwan, identified as pivotal in the Asian drug trafficking chain, has been experiencing a surge in illicit drug-related issues. Wastewater-based epidemiology (WBE) has emerged as a promising approach for comprehensive evaluation of actual illicit drug usage. This study presents the first WBE investigation of illicit drug consumption in Taiwan based on the analysis of wastewater from four wastewater treatment plants (WWTPs) in the Taipei metropolitan area. Additionally, it demonstrates a high correlation between the amounts of illicit drugs seized and influent concentrations over an extended period of time. The reliability of solid-phase extraction and analysis via high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was validated for 16 illicit drugs (methamphetamine, ketamine, cocaine, codeine, methadone, morphine, meperidine, fentanyl, sufentanil, para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), 3,4-methylenedioxymethamphetamine (MDMA), cathinone, methcathinone, mephedrone (MEPH), and 4-methylethcathinone (4-MEC)). Methamphetamine, ketamine, and 4-MEC were consistently detected in all wastewater samples, underscoring their prevalence in the Taipei metropolitan area. Biochemical oxygen demand (BOD) and ammonia nitrogen (ammonia N) were employed to reduce uncertainty in estimations of population size during back-calculation of illicit drug consumption. The results indicate that methamphetamine was the most consumed drug (175-740 mg day-1 1000 people-1), followed by ketamine (22-280 mg day-1 1000 people-1). In addition, urban-related WWTPs exhibited higher consumption of methamphetamine and ketamine than did the suburban-related WWTP, indicating distinct illicit drug usage patterns between suburban and urban regions. Moreover, an examination of temporal trends in wastewater from the Dihua WWTP revealed a persistent predominance of ketamine and methamphetamine, consistent with statistical data pertaining to seizure quantities and urine test results. The study provides encouraging insight into spatial and temporal variations in illicit drug usage in the Taipei metropolitan area, emphasizing the complementary role of WBE in understanding trends in illicit drug abuse.

The thermal degradation and soil recovery of thermal treatment of field-weathered decabrominated diphenyl ether-contaminated soil.

A farm at Taoyuan in Taiwan was highly contaminated with decabrominated diphenyl ether (BDE-209), a widely used commercial brominated flame retardant and persistent in the environment, more than 10 years. Since crops are able to absorb and accumulate BDE-209 from soils in our previous research, posing a hazardous risk for humans, it is essential to develop a practical method of soil treatment. Thermal treatment was studied among different approaches. In our previous study (Ko et al., 2022), we found that heating to 450 °C for 30 min achieved a complete removal of BDE-209 in soil. However, the high temperature significantly decreased the original soil organic matter (SOM) from 2.47% to 0.27%, altering the soil texture, damaging microbial biomass, and thus affecting the revegetation after the thermal treatment. Sugarcane bagasse, a common agricultural residue, served as an amendment to restore soil fertility. Current results indicate that 2.5% bagasse can improve the SOM in soil by up to 2.73% and restore its bacterial composition, making the plant growth conditions similar to those of the untreated contaminated soil. In light of the high removal efficiency provided by the 450°C-thermal treatment and the high recovery efficiency of sugarcane bagasse, the strategy presented in this study serves to be a promising method for sustainable remediation.