Polychlorinated biphenyls (PCB), chlorobenzenes (CB) and organochlorine pesticides (OC) data from river water collected at various sites within the Humber catchment area as part of the Land Ocean Interaction Study project (LOIS). Data were collected at regular weekly intervals and intermittently during periods of high flows. All sites were samples from early 1994 to the end of 1996 except for O12, which was sampled from November 1994 till November 1996. The sampling was carried out by the LOIS team at York University. The unfiltered samples were transported to the Institute of Terrestrial Ecology, Monks Wood, UK, where they were extracted with hexane, cleaned up by alumina column chromatography, concentrated and then analysed for CBs by Gas Chromatography-Mass Spectrometry (GC-MS) and PCBs and OCs by Gas Chromatography with Electron Capture Detection (GC-ECD).