The characteristics of plastic nanoparticles and their effect on zooplankton

Everyday items release of nanoplastics A well-known problem of today’s society is the large plastic pollutions on both land and in the oceans. The macroplastics (5mm to 20 μm) and the microplastics (smaller than 5 mm.) are well studied, and it is generally known that these types of particles are harmful for animals if ingested or entangled. Even though it is generally thought that plastics only degrade into smaller and smaller pieces little is known about the next expected sizes of plastics, the nanoplastics (<20 μm). In this study nanoplastics will be produced by degrading plastics from pacifiers of both latex and silicone and also by degrading the plastic Poly ethylene (PE) from a water bottle. Then the size, characteristics and toxicity of these particles will be analysed. To mimic an accelerated degradation of the monotone tear of everyday use, a stick blender was used to degrade plastics in distilled water. By using a combination of laser scattering and a microscope, the result showed that all the products released nanoplastics. These nanoplastics are around the size of 100 nm. However, the number of plastics that gets released vary between the products. The water bottle released 3.7 million particles/mL, the silicone released 18.7 million particles/mL and the latex released 20.3 million particles/mL as shown in the figure. With the help of Fourier-transform infrared spectroscopy (FTIR) the molecular bonds within the particle could be identified and compared with the raw material. This confirmed that the nanoparticles were still of the original materials Silicone, latex and PE. This agreed with the theory that plastics only degrade into smaller and smaller particles. To get an understanding of the stability of all the particles in water solution the zeta potential were measured. It showed unstable solutions for all the samples when they had been left for a few days. An acute toxicity test was performed with the zoo plankton, Daphnia magna, neither of the plastics showed any significant toxicity in comparison to the controls with distilled water and mixed distilled water. However, a life time test should be made to confirm that these particles are harmless. To conclude, all the plastics degrade into nanoplastics, the particles are instable in a water solution but there is no sign of toxicity after an acute toxicity test, however, more extensive toxicity tests should be made to confirm that these everyday items do not affect our well-being. Bachelor thesis in Molecular Biology 30 hp 2019 Department of biology, Lunds University Supervisors: Tommy Cedervall, Mikael Ekvall, Martin Lundqvist Biochemistry, Lunds University (Less)