Processed fibers are highly present in our daily life and can be either natural, artificial (regenerated cellulose) or synthetic (made with petrochemicals). Their widespread use leads to a high contamination of the environment. Previous studies focus on plastic particles regardless of their type or shape as long as they are smaller than 5 mm. On the contrary, this study focuses exclusively on fibers using a smaller mesh size net (80 μm) to sample freshwater. First, the short term temporal variability of the fibers in the environment was assessed. While exposing the sampling net during 1 minute, a coefficient of variation of approx. 45% (with n = 6) was determined. It was of only 26% (n = 6) when the exposure was of 3 minutes. The assessment of the distribution through the section showed a possible difference in concentrations between the middle of the water surface and the river banks which could be attributed to the intense river traffic within the Paris Megacity. The vertical variability seems negligible as turbulence and current conditions homogenize the distribution of the fibers. A monthly monitoring showed concentrations of 100.6 ± 99.9 fibers/m³ in the Marne River and of 48.5 ± 98.5, 27.9 ± 26.3, 27.9 ± 40.3 and 22.1 ± 25.3 fibers/m³ from the upstream to downstream points in the Seine River. Once these concentrations are converted into fluxes, it seems that the impact generated by the Paris Megacity cannot be distinguished. Investigations on the role of sedimentation and deposition on the banks are required. This study helped fill some major knowledge gaps regarding the fibers in rivers, their sampling, occurrence, spatial-temporal distribution and fluxes. It is encouraged that future studies include both synthetic and none synthetic fibers.
Fibers, Microplastics, Seine River, Paris Agglomeration, Plastics
Dris, R., Gasperi, J., Rocher, V., Tassin, B., 2018a. Microplastic contamination in the Seine River: Spatial and temporal variations of synthetic and non-synthetic fibers. Techniques – Sciences – Methodes 5: 45–53.
Anthropogenic particles (APs) are a very broad category of particles produced directly or indirectly by human activities. Their ingestion by biota is well studied in the marine environment. In contrast, studies on AP ingestion in wild freshwater organisms are scarce despite high contamination levels in some rivers and lakes. In this study, we aimed to evaluate the ingestion of APs and the possible occurrence of APs in the liver and muscle of a freshwater fish, Squalius cephalus, from the Parisian conurbation. After isolation, the particles were analyzed using Raman spectroscopy. In sixty stomachs, eighteen APs were found, half of which were plastics and the other half were dyed particles. Twenty-five percent of sampled individuals had ingested at least one AP. The mean length of the APs was 2.41 mm. No significant difference was found between the sites upstream and downstream of Paris. Additionally, 5% of sampled livers contained one or more APs, which were characterized as microplastics (MPs). No APs were found in the muscle tissue. The majority of APs isolated from stomach contents were fibers, which is similar to the findings of a previous river contamination study. This highlights that fish could be more exposed to fibers than previously thought and that more studies on the impacts of fiber ingestion are required. Despite their low occurrence, MPs are reported, for the first time, in the liver of a wild freshwater fish species. While the pathways and impacts are still unknown, MPs also occur in liver of marine mollusks and fish. Physiological in vitro studies are needed to better evaluate the impacts of such phenomena.
Microplastics, Fibers, Seine River, European chub, Muscle, Liver
Collard, F., Gasperi, J., Gilbert, B., Eppe, G., Azimi, S., Rocher, V., Tassin, B., 2018. Anthropogenic particles in the stomach contents and liver of the freshwater fish Squalius cephalus. Science of the Total Environment 643: 1257–1264.