LONDON – Scientists have identified synthetic microfibres in the digestive systems of seven different species of turtle from the Atlantic, Mediterranean and Pacific oceans. All turtles examined were found to have ingested synthetic microfibres, while other microfibres including rayon and viscose were also in evidence. The research was aimed at filling current understanding gaps in the incidence and levels of synthetic particles in large marine vertebrates. Its findings raise further questions about the issue of microplastic and associated microfibre pollution, and the alarming possibility of tiny fragments of clothing ultimately finding their way into the human food chain.
The researchers used enzymatic digestion methodology, previously developed for zooplankton, to explore whether synthetic particles could be isolated from marine turtle ingesta. They report the presence of synthetic particles in every turtle subjected to investigation which included individuals from all seven species of marine turtle, sampled from three ocean basins, with the Mediterranean turtles containing the most microfibres, followed by the Atlantic and the Pacific.
The paper raises the possibility of multiple ingestion pathways. It says: “These include exposure from polluted seawater and sediments and/or additional trophic transfer from contaminated prey/forage items. We assess the likelihood that microplastic ingestion presents a significant conservation problem at current levels compared to other anthropogenic threats.”
In terms of impact, the paper says: “It remains unknown if and how these synthetic particles will impact turtles. Their size means they will pass through the gut lumen with relative ease (especially, for larger specimens) and therefore their presence does not lead to blockage or obstruction which is frequently reported in association with macroplastic ingestion. Importantly, future work should focus on whether microplastics may be affecting aquatic organisms more subtly, for example, exposure to associated contaminants (heavy metals, persistent organic pollutants and polychlorinated biphenyls) and pathogens, or by acting at cellular or subcellular level.”