Monitoring of microplastics in Japanese oysters (Crassostrea gigas) of the French Atlantic coast (Pays de la Loire, France)

According to the last ten years of research, MPs have been detected in all natural habitats from pole to pole and in all environmental compartments. Monitoring the presence of MPs in marine organisms is currently of high... [ view full abstract ]

According to the last ten years of research, MPs have been detected in all natural habitats from pole to pole and in all environmental compartments. Monitoring the presence of MPs in marine organisms is currently of high importance. The aim of this study was to evaluate the contamination of Japanese oysters (Crassostrea gigas) from the French Atlantic coast which is a species considered as a good bioindicator, filter-feeder with an important socio-economic value.

A total of 60 Japanese oysters were analyzed and sampled in two sites of the French Atlantic coast, in the Pays de la Loire region at two different seasons: autumn 2015 and spring 2016. Cultivated and wild organisms were collected to be compared.

First, a fast protocol for isolation and identification of MPs without visual sorting was set up and validated using spiked samples. Oysters, taken individually, were subjected to digestion, sedimentation and filtration. MPs were then detected and identified directly on the membrane filters using µFTIR spectroscopy in reflection mode.

More than 120 MPs of six different chemical natures were found and identified in the sampled oysters; PP and PE representing 70% of the identified MPs. Their size ranged from 20 to 1300 µm with 53% of the particles ranging from 50 to 100 µm. The concentration of MPs was evaluated as an average of 2.1 MPs per oyster and 0.2 MPs per gram of soft tissue. Significant differences in the MP quantities according to the sampling site and the season were observed.