Development of Microplastic Sampling and Pretreatment Device by Μ Raman Spectroscopy and Distribution Characteristics of Microplastics in Fresh Water

In this study, our groups made sampling device that could both apply to small size MPs sampling and size separation. Sampling was based on physical filtration through a stainless filter. Wet peroxide oxidation process and density separation were performed to separate microplastics after collecting all particles. The device was made of aluminum alloy and the filter was fabricated with 1 to 45 μm pores by woven stainless filter. The recovery rate of the sampling device was over 93.84±2.88%, and the cross-contamination rate was also very low. Using this device, we sampled major water supply sources such as river and lake in Republic of Korea by depth. A μ-Raman spectrometer capable of analyzing the shape, size, and type of MPs with a size of 20 μm or less was used to confirm the distribution of MPs of various densities present according to the water depth. As a result, it was confirmed that the distribution type of MPs in the upper, middle, and lower depths was different. Especially, some high-density plastics such as PET and PVC were not detected in surface samples. These results indicate that small size of MPs, which has toxic possibility to human, have different distribution characteristics depending on the depth of water supply sources, so the results will be an important basic data for treatment and regulation.