Organic micropollutants as markers of urban sources of pollution in the Suquia river (Argentina, South America)

VALDES, MARIA EUGENIA; RODRIGUEZ CASTRO, C.; GIORGI, A.; BARCELÓ, DAMIÁ; AMÉ, MARÍA VALERIA; RODRIGUEZ MOZAZ, S.

Oslo

Conferencia; 16th International Conference on Chemistry and the Environment; 2017

The use of chemical compounds to track different sources of pollution has been an area of growing interest in the last years and more recently, hydrophilic and stable markers have been proposed as tracers of soluble contaminants in aquatic systems. Harwood (2014) reviewed the use of organic chemicals named ?molecular markers? to determine anthropogenic sources of organic matter in natural waters, and pointed out specific compounds associated with pollution by landfill leachate, road runoff and sewage. In sewage, as well as municipal effluents, pharmaceuticals are an important group of contaminants, among which antibiotics have gained great concern because of their worldwide usage in both human and veterinary medicine (as growth promoters in livestock animal production, as feed additives in fish farming, etc.) and the development and spread of antibiotic-resistant bacteria. The objective of this work was to evaluate the presence of compounds stated in the literature as markers of urban pollution and pharmaceuticals (including a broad set of antibiotics) in the Suquía River (Córdoba, Argentina). The analytes selected were: propyphenazone, N,N-diethyl toluamide (DEET), clofíbric acid, mecoprop (as markers of dump leachate/runoff); carbamazepine, caffeine, acesulfame K and 80 pharmaceuticals (as markers of municipal effluents). Five sampling points were selected in the Suquía River, along the area of urban anthropogenic pollution of Cordoba city (1,330,023 inhabitants): S1- control (upstream Córdoba city), S2 (dump area), S3 (downstream Campo La Ribera and a city ringway channel discharge), S4 and S5 corresponding to 6 and 10 km downstream Cordoba city wastewater treatment plant effluent discharge. Water, sediment and natural biofilm samples of the river were taken in 2 monitoring campaigns, to consider seasonal variations in the river flow (higher river flow: May 2016; lower river flow: October 2016). Physicochemical parameters were measured in water and sediment and a water quality index (developed previously by the group) was calculated. For the analysis of organic chemical markers, water samples were filtered through 0.45 µm to separate particulate matter from dissolved water and kept at -80ºC until extraction by SPE. Particulate matter was dried at 30ºC, sediments and biofilms freeze-dried and all solid matrixes kept at -20ºC until extraction by pressurized liquid extraction, bed disruption, etc. Organic micropollutants were determined by UPLC-ESI(QqLIT)MS/MS analysis. The water quality index showed the impact of anthropogenic pollution of Cordoba city, following the decreasing water quality order: S1>S2≈S3>S4≈S5. Higher organic micropollutants loads were found along and downstream Cordoba city compared to S1-control, in both seasons. Compounds were detected in the four matrixes under study (in the ng/L-ng/g range), with higher frequency of analgesics/anti-inflammatories, β-blockers, psychiatrics, anti-hypertensives and antibiotics.Some associations between sources of pollution and organic compounds were found, being most noticeable in S4 and S5 were there is a markedly pollution by a point source: the wastewater treatment plant effluent of Cordoba city.