Environmental biofilms versus POCIS: efficiency to highlight environmental presence of pharmaceuticals and their effect on biofilm microbiome

Pharmaceutical compounds (PhC) are an important environmental issue, because of their high variety, potentially toxic byproducts and bioactivity at low concentrations. PhC concentrations in WWTP effluents often exhibit large and rapid variations that are difficult to record. Passive samplers are helpful to incorporate spot pollution events and register PhC occurrence at low concentrations. In this work, we aim at (i) studying PhC accumulation in polar organic chemical integrative samplers (POCIS) and environmental biofilms exposed to urban (U) and hospital (H) treated effluents and (ii) evaluating the capacity of POCIS to predict changes in biofilm microbiome over a defined time period. Moreover, we (iii) determine the enrichment of PhC in the recipient river to evaluate levels of environmental contamination and potential effects on microbial biofilms. Biofilms and POCIS were installed in treated effluents and in the recipient river to measure the accumulation of PhC. In parallel, microbial biofilm communities were studied using DNA metabarcoding. The duration of each deployment was one month and the experiment was repeated six times. The performance of POCIS and biofilms to quantify PhC was depending on the compound. POCIS appeared well adapted to reveal contamination trends similar to these in the water column and to identify key PhC drivers of microbial changes. POCIS have the potential to predict pharmaceutical effects on biofilm community structure.