River biofilms play fundamental roles in shaping the architecture of aquatic systems.
Sorption to biofilms was thought to be a crucial mechanism controlling the fate and
transport of trace emerging contaminants. This study focused on the role of in situ
colonized river biofilms in the early fate of phthalate esters (PAEs) and bisphenols
(BPs) at trace concentrations in a representative urban river. PAEs and BPs were readily
sorbed to biofilms with uptakes of 38.2-162.5 mu g/g for PAEs and 1787.7-4425.6 mu
g/g for BPs, respectively. The total mass and characteristics of the colonized biofilms
varied in response to seasons and water qualities. The biofllm colonized in the downstream
of a wastewater treatment plant exhibited the highest sorption capacity among the
tested sites, possibly attributed to the higher organic contents of biofilms owing
to the elevated availability of nutrients. Correlation analysis indicates that certain
water qualities, e.g., TN and NH3-N, and biofllm properties, e.g., organic and polysaccharide
fractions could be selected to predict the sorption capacities of river biofilms.
Hydrophobic partitioning into organic matter appears to be the dominant sorption mechanism
and biofllm polysaccharides were probably responsible for the adhesion of tested compounds.
The contaminant partitioning into biofilm and sediment at mass/volume ratios typical
for small rivers suggests that the biofilm could serve as an important sorbing matrix
for the trace organic contaminants as compared to the sediments. Our work yields new
insights into the early uptake and accumulation of trace plasticizers by natural biofilms,
which is of significance in understanding the subsequent transport of trace organic
contaminants in fluvial systems. (C) 2018 Elsevier Ltd. All rights reserved.