Degradation of Commonly Used Plastics into Nanoparticles

The impact of degraded nanosized plastics Large amounts of plastics are released into the environment worldwide every year. An estimated 4 to 12 million metric tons (Mt) of plastic waste, generated on land, entered our oceans in 2010 alone. Of the 6300 Mt of plastic, generated in 2015, around 79% of which was collected in the natural environment. The enormous amounts of this release have been identified as an important concern for some time and is recognized as an important pollution related issue. It is well known that plastics are ending up in the guts of animals and plastic debris have been found in all major ocean watersheds. As a result of these growing issues, the concerns of the released plastic’s impact on nature and the aquatic life have grown. Only recently have studies about the impact of nanoplastics been presented, as opposed to the more researched field of microplastics. Nanosized plastic may pose a more severe danger to aquatic life than micro sized plastic. Consequential of their small size, they can travel through food webs and even make tissue penetration and accumulation in organs possible. Due to this narrow knowledge of nanoplastics we decided to construct a study of the degradation of different plastics, latex and silicone from pacifiers, water bottle and ICA shopping bag, and its impact on animals, using Daphnia magna. The degradation techniques that we used was mechanical, heat and UVB-light. These three approaches were chosen to mimic the degradation occurring naturally. As in boiling pacifiers, as the plastic continuously move by wind and waves, and scraped over rocks and sand, and as plastic laying around in nature getting exposed to UV-light. From our results, we can state that there are nanoparticles produced using mechanical force and to some extent heat. Degrading by UVB-light did not result in any produced nanosized particles. The biological test did not show any different results between the plastic tests and the controls for the three plastics except the ICA shopping bag. The Daphnia fed with ICA shopping bag survived for a tremendously longer time. The degradation of the plastics was done mechanically by using an immersion blender, breaking down by boiling the plastics and lastly by exposing them to UVB-light. To characterize the produces material four different methods were applied. We performed nanoparticle tracking analysis (NTA) to determine size and concentration. To determine surface charge Zeta potential measurements were performed. Attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) was executed to study the chemical composition of the nanoparticles. Finally, to characterize size further, and morphology, the blended plastic samples were examined by transmission electron microscopy (TEM). This study has opened up for multiple new questions. What will happen with other plastics? What other degradation processes can happen in the environment? What is the reason for the Daphnia to survive only on the ICA shopping bag? Hopefully, these questions will be answered soon. Plastics may be a huge problem now, we can only hope the future will be brighter with less plastic and clean oceans. For us, for the wildlife and for the planet. Final paper for bachelor’s degree in Molecular biology 30 hp 2019 Biological institution, Lund university Supervisors: Martin Lundqvist, Mikael Ekvall and Tommy Cedervall Biochemistry Lund university (Less)