Quintana Martin-Montalvo, B., Moro, I., Lamprecht, T., Miliou, A., Antichi, S., Ashok, K. Pietroluongo, G. A Cost-Efficient Standardised Methodology for Microplastics Analysis: Case Study of Cetaceans and Mediterranean Monk Seals Stranded on Samos Island Coastline, Greece. World Marine Mammal Science Conference 2019.

Abstract:

The real impact of plastic pollution on the marine ecosystem is an issue yet to be fully assessed due to the lack of data and logistic difficulties, especially in remote locations. This study proposes a cost-efficient field methodology to be adopted as a model for microplastic quantification in sentinel species of the marine ecosystem.

A preliminary analysis of the presence of microplastics was conducted on a total of 12 dolphins (7 Stenella coeruleoalba, 4 Delphinus delphis, 1 Tursiops truncates) and 3 Mediterranean Monk seals (Monachus monachus) found stranded on the shores of Samos Island, Greece, between 2017 and 2019. Necropsies were conducted in situ or in the laboratory when possible. The entire digestive system was isolated from the oesophagus to the last tract of the large intestine. All samples were sieved (mesh sizes: 500μm and 200μm), treated to dissolve the organic matter content, and filtrated through glass fibre filters. The slides were observed under x40 magnification to quantify and categorise the microplastic items into type (fibre; fragment), colour and size. A “hot needle test” was conducted to distinguish between plastic pieces and organic matter. A test for airborne contamination was performed at random. A high concentration and variety of microplastics were found throughout each tract of the digestive systems of all the animals analysed, confirming the wide scope of the plastic pollution affecting the top predators of the trophic chain. These results prove the efficiency of the proposed field methodology to fill the data deficiency and improve the crucial research on marine litter impact.