Evaluation of sedimentary bacterial community dynamics and contamination assessment of lower Des Plaines River

•Heavy metals and microbial parameters displayed significant spatiotemporal variations in the sediments.•Wastewater effluents modulates microbial community and biomass in a complex way.•Pollution associated bacterial groups were recorded from the effluents at the outfall of the WWTP.•Metal tolerant microbial community potentially help to maintain microbial biomass.