Occurrence and seasonality of raw and drinking water contaminants of emerging interest in five water facilities

The goal of this work was to investigate the occurrence of contaminants of emerging interest (CEI) in source surface water (SW; river water) and drinking water (DW; tap water) from five drinking water treatment plants (DWTPs) in the Province of Quebec, Canada. A total of 28 sampling campaigns were conducted to collect SW and DW samples from each DWTP from June 2016 to July 2017. The seven targeted CEI, including acetaminophen, salicylic acid, caffeine, carbamazepine, ibuprofen, sulfamethoxazole and drospirenone, were analyzed using solid-phase extraction-ultra pressure liquid chromatography-mass spectrometry (SPE-UPLC-MS/MS) for all collected water samples. The selected CEI were detected in all SW and DW samples, with the exception of drospirenone, which occurred in amounts that were below the limit of detection in one DWTP in June and July 2016. In all the SW samples, caffeine was detected and had the highest median concentration range (12.3-91.0 ng/L), followed by acetaminophen (7.9-85.0 ng/L) and salicylic acid (21.6-39.0 ng/L). In the DW samples, salicylic acid was detected and had the highest median concentration range (20.5-50 ng/L), followed by caffeine (5.2-21.8 ng/L), and acetaminophen (5.0-7.7 ng/L). Carbamazepine, ibuprofen, and sulfamethoxazole primarily occurred in amounts between the limit of detection and limit of quantification in SW and occurred below the limit of detection in DW. All the DWTPs exhibited a similar trend in the removal of CEI, which include acetaminophen (<= 97.6%), followed by caffeine (71.0-86.5%) and salicylic acid (<50.0%). Varying levels of efficiencies were observed among the removal strategies for CEI under study, which were mainly associated with the contaminant concentration in SW in the case of acetaminophen, and with the treatment processes in the case of caffeine and salicylic acid. (C) 2020 Elsevier B.V. All rights reserved.