Environmental impact of nanoplastics from fragmentized consumer plastics
The smallest microplastics are called nanoplastics. Due to the small size, they are difficult to find and study, but have different biological impact then larger pieces of plastics. The project has used model polystyrene nanoplastics to fill knowledge gaps about life-time toxicity to filtrating zooplankton D. magna and to identify what proteins from the gut of D. magna bind to toxic and non-toxic nanoplastics. Nanoplastics in nature will come from break-down of larger plastics. The project has mechanically mimicked this process and produced nanoplastics from 8 different plastics and rubbers using 14 different daily used products.
The nanoplastics are irregular in shape and highly oxidized compared to the starting material. Nanoplastics from HDPE and PLA are not toxic to D. magna. On the contrary D. magna exhibit increased lifetime probably due to that the nanoplastics can support bacterial growth which can be used as food by D. magna. UV-irradiation further degraded polystyrene nanoplastics. This, together with the bacterial growth, may imply faster plastic degradation in nature than believed today.
The project has been funded by the Swedish EPA’s environmental research grant, which aims to fund research in support of the Swedish EPA and the Swedish Marine and Water Authority’s knowledge needs.