Sampling Microplastics in Beach Sediments and Analysis Using FTIR Spectroscopy

Abstract

The focus of the thesis is to find suitable methods to collect and separate microplastics from beach sediments, analyse them with microscope and identify the polymer types with FTIR spectroscopy. Microplastics are plastic particles that are less than 5 mm diameters and they originate from either fragmentation of macroplastics or production of plastics in micro meter size. This results in steadily increasing amount of microplastics litter in the environment. Microplastic pollution in aquatic environment is increasing daily and there are not enough resources to prevent it. Microplastic sampling in marine environment occurs on beach sediments, sea bottom and sea surface. This thesis focuses on sampling microplastics on sandy beaches with bulk and selective sampling methods. Samples were collected from different locations around the world. Micro particles were separated from sand samples by density separation and the floating micro particles were used in two different separation methods that are wet peroxide oxidation and vacuum filtration. Wet peroxide oxidation is a method to dissolve organic matters in the samples which failed during the experiment. Vacuum filtration method was used with filter paper that is effective for removing samples to analyse in FTIR spectroscopy. Many red and blue coloured fibers were found in each sample with microscopic analysis and they were failed to identify with transmission method in FTIR. Most of the microplastics found in the samples were HDPE and a few of them were identified as PP. Unexpectedly there were no PET found in the samples, however one sample was found as PVC with the possibility of 48% during the analysis of FTIR spectroscopy.