Investigation of Organic Pollutants in Sediments of the Kaduna River, North Central Nigeria

River sediments serve as sinks and secondary sources of organic pollutants, making their chemical characterisation essential for comprehensive environmental monitoring of freshwater systems. This study investigates the presence and distribution of polycyclic aromatic hydrocarbons and selected chlorinated organic compounds in sediment samples collected from five stations along the Kaduna River in North Central Nigeria. Samples were collected seasonally, extracted by Soxhlet extraction with dichloromethane and hexane, and analysed by gas chromatography-mass spectrometry. Diagnostic ratios were used to assess pollution sources. Total organic carbon was determined to evaluate the relationship between sediment organic content and contaminant partitioning. Results indicate the presence of naphthalene, acenaphthylene, fluoranthene, pyrene, and benzo(a)pyrene in all sediment samples, with higher concentrations recorded near Kaduna city and downstream of industrial effluent discharge points. Diagnostic ratio analysis suggests a mixture of pyrolytic and petrogenic sources, consistent with vehicular runoff, industrial discharge, and combustion-related inputs. Total PAH concentrations at certain stations exceeded probable effects concentration thresholds, suggesting potential ecological risk. The study recommends the integration of sediment quality guidelines into the regulatory framework for Kaduna River management and enhanced monitoring of industrial discharge in the catchment. Keywords: polycyclic aromatic hydrocarbons, sediment, Kaduna River, GC-MS, organic pollutants