Inhibitory effects of dissolved organic matter on erythromycin bioavailability and possible mechanisms

[Display omitted] •DOM decreased bioaccumulation of ERY in aquatic organisms.•SRHA and SRFA inhibited ERY bioavailability greater than the other DOM.•ERY KDOC values increased with the content of humic and fulvic acid-like compounds.•DOM interacted with ERY via reactions of −COO− with ERY+ and H-bonding.•Inhibitory effects of DOM were related with its sources and properties. Macrolides are widely used antibiotics with ubiquitous occurrence in aquatic environments. Unlike many emerging contaminants, macrolides are positively charged on their amine groups and are likely to interact with negative charge groups of dissolved organic matters (DOMs), which may alter macrolide bioaccumulation but yet to be explored. Here we evaluated the effects of different DOM (LeHA, PPHA, SRHA and SRFA) on erythromycin (an important macrolide) bioaccumulation into aquatic biota with 14C tracing. Results showed that ERY uptake in organisms was significantly inhibited by DOM (P