The University of Siena has published the first results of its analyses of contaminants found in plastic waste abandoned at sea and collected on Italian beaches. We explore them in the editorial by the president of Legambiente.
The phenomenon of marine litter now represents the second global environmental emergency after that of climate change. The presence of plastic in the sea is a serious problem due to its effects on the environment and marine fauna and, consequently, due to the risk that fish may become a vehicle for toxic substances that end up directly on our plates.
This risk is substantiated by the experimental study Plastic busters, which found mercury, polychlorinated biphenyls, DDT and hexachlorobenzene in plastic waste abandoned at sea and collected by Legambiente volunteers. On the occasion of World Oceans Day, the first results of the analyses carried out by the University of Siena for Plastic busters were released — the first experimental project in the Mediterranean on this issue, also in light of the effects on the food chain linked to the ingestion of plastics at sea.
To begin with, contaminants were found in every sample analysed, at concentrations that varied according to the area, the nature of the polymer and the degree of ageing of the waste. The sampling covered a single type of floating plastic: "sheetlike user plastic", that is, bags, sheets and sheeting, which make up the most abundant fraction of marine litter.
Read also: Perché plastica e microplastiche sono la minaccia dei nostri oceani
The waste analysed by the researchers at the University of Siena was collected and sampled by Legambiente's Goletta Verde last summer during its voyage along the Peninsula. For each sample, the crew of the environmental vessel recorded the GPS position, took photographs, filled in a details sheet and followed a collection and preservation procedure as required by the University of Siena's protocol. Laboratory analyses were then carried out, with the polymer composition of each sample evaluated using infrared spectrometry. The analysis revealed that 86 per cent of the macroplastics analysed consisted of polyethylene and 14 per cent of polypropylene.
With regard to the analysis of organochlorine synthetic compounds and mercury found on floating microplastics, the study shows that all samples contained appreciable levels of these contaminants. The data show an increase in concentrations during an initial period at sea, followed by a subsequent decrease as the material ages: in all likelihood, as the degradative processes that plastic undergoes once at sea advance, it releases part of its contaminant load.
Read also: Pete Ceglinski. Anche un solo Seabin può fare la differenza per rimuovere la plastica dagli oceani
The results of the study prompt us to deepen this type of approach in analysing the phenomenon, and once again highlight the need to defend our planet's waters from waste by reducing the consumption of single-use products and promoting recycling and the circular economy. As well as, of course, educating citizens not to abandon waste in the environment. If nothing else, so as not to find it on their plates.
