Contaminants of emerging concern fate and fluvial biofilm status as pollution markers in an urban river

Contaminants of emerging concern (CEC) are still under research given the vast diversity of compounds reaching freshwater ecosystems and adverse effects they might cause. In this study, the environmental fate of 73 CEC, comprising sweeteners, stimulants and several pharmaceutical therapeutic classes, and changes in fluvial biofilm photosynthetic parameters were evaluated in a semi-arid urban river receiving diffuse and point sources of pollution (Suquía river, Argentina). Out of the 37 CEC detected, 30 were quantified in surface water (n.d. - 9826 ng/L), 10 in biofilm (n.d. - 204 ng/gd.w.) and 9 in the clay fraction of sediments (n.d. - 64 ng/gd.w.). CEC distribute differently among the 3 matrices: water phase presents the biggest diversity of compounds (14 CEC families), being analgesic/anti-inflammatories the most abundant family. Antibiotics largely predominated in biofilms (7 CEC families), while the stimulant caffeine and some antibiotics where the most abundant in sediments (6 CEC families). Different CEC accumulated in biofilms and sediments upstream and downstream the city, and big shifts of biofilm community occurred downstream WWTP. The shift of biofilm community upstream (F0 > 0) and downstream the WWTP (F0 = 0) shows a sensitive response of F0 to the impact of WWTP. Biofilm photosynthetic parameters responded in less impacted urban sites (sites 1, 2 and 3), where significant correlations were found between ketoprofen and some antibiotics and biofilm parameters. The diversity and amount of CEC found in the urban section of Suquía river alert to the magnitude of point and non-point sources of pollution.

This study has been co-financed by the Agencia Nacional de Promoción Científica y Técnica Argentina (FONCyT PICT-2019- N° 2892), the International Atomic Energy Agency (CRP: D52039, CN: 18849) and by the European Union through the European Regional Development Fund (FEDER). It has also been partly supported by the Economy and Knowledge Department of the Catalan Government through a Consolidated Research Group (ICRA-ENV-2021 SGR 01282). The Ultra-Performance Liquid Chromatograph coupled to a hybrid triple quadrupole linear ion trap mass spectrometer detector (Acquity UPLC-MS QTRAP 5500, Waters-SCIEX) received support from the CERCAGINYS program, funded by the Spanish Ministry of Science and Innovation. Sara Rodríguez-Mozaz thanks the Ramon y Cajal program (RYC-2014-16707) from the Spanish State Research Agency of the Spanish Ministry of Science, Innovation and Universities (AEI-MCIU). ICRA researchers thank funding from CERCA program. Argentinean authors would also like to thank CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas-Argentina), FCQ - UNC (Facultad de Ciencias Químicas – Universidad Nacional de Córdoba), ISIDSA/ICYTAC (Instituto Superior de Investigación, Desarrollo y Servicios en Alimentos/Instituto de Ciencia y Tecnología de Alimentos Córdoba) and Sci-Hub for useful access to knowledge.

Peer reviewed