Assessment of drugs and personal care products biomarkers in the influent and effluent of two wastewater treatment plants in Ho Chi Minh City, Vietnam.

Wastewater samples were collected at the influent and effluent of two wastewater treatment plants (WWTPs) in Ho Chi Minh City, Vietnam and then pooled to daily samples over multiple days using 6 hourly grab samples. The aim was to provide a first assessment of the occurrence, consumption, removal and release of a range of organic chemicals including pharmaceuticals and personal care products (PPCPs), illicit drugs, an artificial sweetener, tobacco and its metabolites and alcohol biomarkers (referred to here as DPCPBs). Nineteen DPCPBs were detected via direct measurement of filtered wastewater on LC-MS/MS with a concentration range of 0.05-38μg/L. Caffeine and paracetamol were the most prominent compounds detected in the influent, while acesulfame was found at the highest concentration in the effluent of both WWTPs. Mean concentrations of metabolites of tobacco (nicotine: 7.6μg/L, cotinine: 1.4μg/L and hydroxycotinine: 1.7μg/L) and alcohol (ethyl sulphate: 3.3μg/L) were lower than those of European countries. Consumption rates based on daily mass loads and catchment population data obtained from the WWTPs were <10g/d/1000 pp for the majority of selected PPCPs, except for caffeine (300g/d/1000 pp) and paracetamol (320g/d/1000 pp). Consumption rates for codeine and methamphetamine were 0.05g/d/1000 pp and 0.17g/d/1000 pp, respectively. Consistently across the two WWTPs most of the chemicals (10) showed >80% apparent removal rate from the wastewater, three chemicals showed apparent removal efficiency of approximately 50%; and the removal efficiency could not be assessed for 5 compounds due to their low concentrations in the influent. Based on the fraction of treated and untreated wastewater (10:90) that is released into the receiving environment we estimated a total discharge of approximately 170kg per day of DPCPBs in Ho Chi Minh City.