Spatial monitoring of organohalogen compounds in surface water and sediments of a rural-urban river basin in Tanzania

► Levels of persistent organohalogenated pollutants in Pangani river basin are low. ► Residues of OCPs mainly originate from past applications in the sugarcane plantations. ► p,p′-DDE was the main metabolite recovered in the samples, indicating old inputs. ► PCB profiles dominated by low-chlorinated compounds indicating recent contamination ► Concentrations of PCBs and PBDEs linked to urbanization and transportation.