RÉSUMÉ
The Biobío River basin is highly impacted by a variety of anthropogenic activities such as pulp mills and urban wastewaters subjected to different treatment processes. This work assesses for the first time, the contamination source and biological effects (estrogenic and dioxin-like activities) in the river basin by the determination of 45 organic microcontaminants in seven sediment samples. Pressurized solvent extraction combined with two-dimensional comprehensive gas chromatography coupled to time of flight mass spectrometry was employed for this purpose. The organic microcontaminants identified comprise monoterpenes, sesquiterpenes, diterpenes, ionones, lineal alkyl benzenes, polycyclic aromatic hydrocarbons, musk fragrances, sterols and phathalate esters. The presence of pine and eucalyptus pulp mill effluents increased the abundance of resin-derived neutral compounds and monoterpenes respectively. A principal component analysis showed that the Biobío River basin was impacted by domestic wastewater treatment plants (WWTPs), pine or eucalyptus Kraft pulp mills and pyrolytic and pyrogenic processes. Finally, the recombinant yeast assays showed that the presence of estrogenic and dioxin-like activity was mostly located in sediments impacted by domestic WWTP effluents.