Chiral drugs, such as amphetamines, ephedrines, venlafaxine, and atenolol, break down differently depending on their mirror-image forms during wastewater treatment and in rivers. Monitoring at seven wastewater treatment plants (using activated sludge or trickling filters) and six river sites over nine months showed that the extent of this enantiomer-specific fate varied by drug, treatment method, and season. Atenolol and MDMA showed high stereoselectivity, activated sludge produced more stereoselectivity than trickling filters, and stereoselectivity in the environment was higher in spring and summer.
Amphetamine-like compounds undergo stereoselective degradation during wastewater treatment and in receiving waters, with microbial processes favoring the S-(+)-enantiomer over the R-(-)-enantiomer. In controlled laboratory microcosms simulating activated sludge, all four compounds—amphetamine, methamphetamine, MDMA, and MDA—showed preferential breakdown of the S-(+)-enantiomer, while R-(-)-enantiomers remained largely undegraded, indicating greater persistence. Amphetamine was the most biodegradable, followed by MDMA and methamphetamine. Photochemical processes degraded MDMA and methamphetamine but were not stereoselective. Biodegradation of S-(+)-methamphetamine produced S-(+)-amphetamine, and racemic MDMA degraded stereoselectively in activated sludge, enriching R-(-)-MDMA and forming S-(+)-MDA. Only mild stereoselectivity occurred during MDMA degradation in river water, likely due to different microbial communities. Kinetic studies confirmed MDMA's recalcitrance.
Wastewater-based epidemiology (WBE) can provide objective and timely information on the use of new psychoactive substances (NPS), originally designed as legal alternatives to internationally controlled drugs. NPS have rapidly emerged on the global drug market, posing a challenge to drug policy and a risk to public health. A WBE approach monitored over 300 NPS, plus fentanyl and norfentanyl, in influent wastewater from 12 European cities during March–June 2021. Fentanyl, norfentanyl, and eight NPS were quantified, with at least three substances found in each city. N,N-dimethyltryptamine and 3-methylmethcathinone (3-MMC) were the most common; 3-MMC had the highest mass loads, up to 24.8 mg/day/1000 inhabitants. Spatial trends and a changing weekly profile for 3-MMC were observed. WBE is a useful tool to complement common indicators for public health protection.