The seasonal pattern of microplastics (MPs) contamination of the French littoral area of the Pertuis Charentais, one of the main French shellfish production regions, was assessed for the first time, between May 2019 and May 2020 at four different sites. The reference site was located at “Ile de Ré” and the other sites were located in the estuaries of the Sèvre Niortaise, Charente and Seudre rivers. Both blue mussels (Mytilus edulis) and Pacific oysters (Magallana gigas), that are considered sentinel species for the quality of the marine environment were analysed, along with sediment and seawater samples. MPs were extracted from each sample, counted, measured and sorted by colour and type. Micro-Raman spectroscopy was used to determine the proportion of confirmed MPs and the polymer types. The results showed that the contamination of mussels by fibres and fragments (1.9 ± 2.1 MPs/g ww) was significantly higher than for oysters (0.4 ± 0.4 MPs/g ww). Specifically, the contamination by fibres in both species was significantly greater than the contamination by fragments. Significant variations of MPs contamination were observed across the seasons and sites in bivalves, and depended on the species and the type of MPs (fibres or fragments). Mean concentrations of MPs measured in water and sediment were 0.007 MPs/L and 210 MPs/kg dw, respectively. Finally, blue was the dominant colour for fibres (79 %) and fragments (81 %). Blue fragments were mainly made of PS (70 %) followed by PC (18 %) and PP, PA or PLA (3 %) whereas blue fibres were mainly made of PA (80 %) followed by PET (13 %) or PP (7 %). This rare environmental case study of long-term chronic exposure of farming areas to MPs provides new knowledge on in situ variations of plastic fibres and fragments contamination throughout the seasons.

2019 年 5 月至 2020 年 5 月期间，在四个不同地点首次评估了法国主要贝类产区之一 Pertuis Charentais 沿岸地区的微塑料 (MPs) 污染的季节性模式。参考地点位于“Ile de Ré”，其他地点位于 Sèvre Niortaise、Charente 和 Seudre 河的河口。蓝贻贝 ( Mytilus edulis ) 和太平洋牡蛎 ( Magallana gigas)，被认为是海洋环境质量的前哨物种，以及沉积物和海水样本进行了分析。从每个样品中提取 MP，按颜色和类型进行计数、测量和分类。微拉曼光谱用于确定确认的 MP 的比例和聚合物类型。结果表明，贻贝的纤维和碎片污染（1.9 ± 2.1 MPs/g ww）明显高于牡蛎（0.4 ± 0.4 MPs/g ww）。具体而言，两种物种中纤维的污染明显大于碎片的污染。在双壳类动物的不同季节和地点观察到 MPs 污染的显着变化，并且取决于 MPs 的种类和类型（纤维或碎片）。在水和沉积物中测得的 MPs 平均浓度为 0。007 MPs/L 和 210 MPs/kg dw，分别。最后，蓝色是纤维 (79%) 和碎片 (81%) 的主要颜色。蓝色碎片主要由 PS (70%) 制成，其次是 PC (18%) 和 PP、PA 或 PLA (3%)，而蓝色纤维主要由 PA (80%) 制成，其次是 PET (13%) 或 PP ( 7%）。这一罕见的关于农区长期长期接触国会议员的环境案例研究提供了关于整个季节塑料纤维和碎片污染的原位变化。