We reconstruct the chronology of organochlorine pesticides (OCPs) releases and study the role of sediment characteristics (e.g organic matter) in the interpretation of this chronology. For that, sediment cores MAR16-02 and MAR15-01 were collected downstream of the Eure River watershed, the main tributary of the Seine estuary (France).The analysis of particulate OCPs in the MAR16-02 sediment core was performed using microwave-assisted extraction, with toluene:acetone mixture for extraction. Following the microwave-assisted extraction, a gas chromatograph (7890B, Agilent, US) coupled to a mass spectrometer (MS; 7000C) was used to measure the concentrations. Organic matter parameters from MAR15-01 sediment core was measured by Rock-Eval 6.