Multitrophic and experimental studies on plastic abundance and their potential effects on marine organisms from Mediterranean Sea

The environmental pollution is one of the main issues of last decades, despite the many kinds of pollutants arising from many sources, one of the main concerns for scientific community is the Plastic Pollution. The plastic contaminants, especially those of micro-size, can follow the entire cycle of ecosystems contaminating many different environments including both vegetables and animals’ organisms in which the last trophic step are humans. The plastic pollution is already persistent worldwide and, in all environments, from air to soil and water masses. Among these last, the Mediterranean Sea is one of the main polluted marine environments, reaching the sadly known name of “The Plastic Soup”. Considering both the high amount of plastic daily enters seas and oceans and the ecological importance of the Mediterranean Sea, the aim of this study was to survey the plastic contamination status of some marine species that inhabit the basin. The study was divided in two phases: first environmental survey, and second in house experiments to assess microplastic effects on biota. During the environmental survey, different marine animal species were analysed, both caught by trawling fishing and sampled, and the plastic contents analysed and characterized. In total were counted 599 plastic items in 527 specimens (mean 1.3 plastic/specimen) belonging to 15 species in which 45.16% organisms were positive to plastic ingestion. The particles analysed by spectroscopies analysis were cellulose (CL), Kraton G, Polyamide (PA), Polyethylene (PE), Polypropylene (PP), Polytetrafluoroethylene (PTFE), Rayon and Nylon. During the second phase of the study was valuated the influence of microsphere of PE (10µm diameter) on feeding behaviour and life cycle of the brine shrimps Artemia salina used as experimental zooplankton model. The plastics microspheres were administered at different concentrations 0,1,10,102,103,104 MPs/ml in two different groups: Group A (without food source) and Group B (with food source). The ingestion degree was observed in treatment A4, A5 and from B1 to B5 and the main variations between the two groups was observed at exposure times T0, T6, T12, T24 vs. T48 in the Group A and at T0, T6, T12, T24 vs. T96 in Group B. The trial highlighted the influence of MPs on growth in A. salina as well: the main variance in Group A was between A0 and all other treatment while in Group B the MPs less influenced the body development than Group A. The comparison between the multitrophic and experimental approaches to plastic ingestion increased the knowledge regarding the dynamics that regulate the plastic distribution in the environment using organisms of different taxa as propagation vector. Moreover, the influence of plastic particles used during experimental phases, allows to understand the potential effect of MPs to the development stages of zooplankton.