Impacts of some recyclable plastic on marine key species

The aim of this study was to detect the acute ecotoxicological effects of three microplastics (MPs) and their leachates derived from plastic-made packaging in some marine organisms. The MPs were made of polyethylene (PE 4), polypropylene (PP) and polystyrene (PS 6) (≤ 38 μm). Lethal responses of leachates and MPs were investigated in Tigriopus fulvus, Gammarus aequicauda, Cymodoce truncata and Idothea baltica. Growth inhibition/stimulation responses in the green microalga Dunaliella tertiolecta were evaluated only for leachates.The results of acute tests with leachates did not cause acute toxicity, in any tested species, even at very higher concentrations. Similarly, PE4 MPs and PS 6 MPs resulted to be non-toxic (LC50 > 100 mg/L) with the exception of G. aequicauda in which PS 6 MPs have determined an acute lethal effect (LC50 = 20.90 mg/L). Acute exposition to PP MPs revealed toxic effects on all crustacean tested species with LC50 values from 2.73 mg/L to 80 mg/L. These results highlight that the current approach for MP risk assessment needs to be deepened, providing alternative endpoints able to monitor the biological effects of MPs tested.