Microplastics in the marine environment, presence in water and interaction with marine organisms

Pollution of the marine environment by microplastics is a topic of increasing concern and it has received a lot of attention in recent years. This work presents a study conducted in the framework of a European project “CLAIM” (Cleaning Litter by developing & Applying Innovative Methods in European seas) in which the Lebanese University is a partner. It aims to develop innovative technologies in order to reduce the amount and impact of plastic pollution on the ecosystem-based services of the Mediterranean and Baltic Seas. The objective of this project is to advance the knowledge on the current status of marine plastic pollution in the Gulf of Gabes area of the Mediterranean Sea, by quantifying and qualifying the microplastics in water and biota samples. The results obtained showed a high abundance of microplastics in all marine compartments studied with an average abundance of 1.16 items/m3 ± 0.83 SD in the water sample. This concentration is relatively high compared to those reported in other Mediterranean regions. Dominance in number of fragments over other shapes of microplastics was reported in all sites. Polyethylene was the main plastic polymer for water samples (73% of the items analyzed are polyethylene). These data underscore that the Gulf of Gabes region is a hotspot for plastic pollution, and this calls urgently for precautionary measures. Concerning the ingestion of microplastics by marine organisms, one blue plastic particle of 0.13 mm is found in 20 tested fishes. In addition, ecotoxicological tests were performed in order to verify whether 1-4 μm and 20-25 μm polyethylene beads are likely to trigger lethal and sub-lethal responses in marine planktonic crustaceans. The results showed that microplastics were accumulated in crustaceans, and may affect mortality specially if no future precautions were taken. These results report a better understanding of the extended threat of microplastics in the marine environment on marine species and humans.