Détection et caractérisation des macro-, micro- et nanoplastiques dans l'estuaire et golfe du fleuve Saint-Laurent, Canada

The St Lawrence River Canada), (despite its potential role in the accumulation and transfer of plastic debris from land to ocean remains poorly documented in this regard. This study aims to fill this gap by providing a baseline assessment of macro micro and nanoplastics MNP) (concentrations in the Estuary and Gulf of St Lawrence EGSL). While macroplastics are generally characterized by FTIR spectroscopy, mass quantification is essential to accurately assess MNP fluxes and their toxicological impacts. In this context, pyrolysis coupled with gas chromatography tandem mass spectrometry Py GC MS/ MS) has proven to be an optimal method. This work helps to overcome the specific analytical challenges associated with the study of MNP in complex environmental matrices, thus providing a framework for improving the reliability and sensitivity of environmental analyses.In environmental terms, this study provides for the first time a detailed overview of the mass concentration, composition and distribution of MNP in surface water and blue/common mussels (Mytilus spp.) from the EGSL. The results show macroplastics concentrations of 0,17 ± 0,11 items/m², MNP in water of 3,800 ± 2,700 ng/L and in blue mussels of 93 ± 53 ng/mg dry weight.From the societal point of view, this study provides unprecedented data on a key Canadian ecosystem, helping to raise public awareness and guide environmental management policies. By reporting on macro and MNP contamination, it provides valuable data for local and global pollution reduction strategies, and for sustainable management of the St Lawrence's natural resources.