Distribution of antibiotics in water, sediments and biofilm in an urban river (Córdoba, Argentina, LA)

VALDÉS, M. EUGENIA ; SANTOS, LÚCIA H.M. ; RODRÍGUEZ CASTRO, M. CAROLINA; GIORGI, ADONIS ; BARCELÓ, DAMIÀ; RODRÍGUEZ-MOZAZ, SARA; AMÉ, M.VALERIA

ENVIRONMENTAL POLLUTION

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2020

0269-7491

In this study, we evaluated the distribution of up to forty-three antibiotics and 4 metabolites residues in different environmental compartments of an urban river receiving both diffuse and point sources of pollution. Solid phase extraction, bead beating disruption and pressurized liquid extraction were applied for sample preparation of water, biofilm and sediment respectively, followed by the quantification of target antibiotics by UPLC-ESI-MS/MS. Twelve antibiotics belonging to eight chemical families were detected in Suquía River samples (67% positive samples). Sampling sitesdownstream the WWTP discharge were the most polluted ones with the highest loads and variety of antibiotics. Concentrations of positive samples ranged 0.003-0.29 μg L-1 in water (max. cephalexin), 2-652 μg kg-1 d.w. in biofilm (max. ciprofloxacin) and 2-34 μg kg-1 d.w. in sediment (max. ofloxacin). Similar total antibiotic concentrations were found in water during wet and dry season. However higher concentrations were detected in biofilm and sediments during the wet season. Fluoroquinolones, macrolides and trimethoprim were the most frequently detected antibiotics in all environmental compartments. Bioaccumulation factors greater than 1,000 L kg-1d.w. were found for norfloxacin, ofloxacin, ciprofloxacin and clarithromycin in biofilms. Partition tosediments was not relevant (pseudo-partition coefficients below 1,000 L kg-1 d.w. for ofloxacin, clarithromycin and trimethoprim). High water quality and organic carbon sediment content were associated with autotrophic communities in biofilm situated upstream WWTP. Instead, downstream the WWTP, there were a low water and sediment quality jointly with the increase of antibiotic concentrations and biofilm biomass. Cephalexin and clarithromycin in river water were found to pose high risk for the aquatic ecosystem, while ciprofloxacin presented high risk for development ofantimicrobial resistance. This study contributes to the understanding of the fate anddistribution of antibiotic pollution in urban 56 rivers, reveals biofilm accumulation as animportant environmental fate, and calls for attention to government authorities tomanage identified highly risk antibiotics.