Stereomicroscopic and Fourier Transform Infrared (FTIR) Spectroscopic Characterization of the Abundance, Distribution and Composition of Microplastics in the Beaches of Qingdao, China

Microplastic pollution is considered to be a major coastal environmental issue worldwide, and studies have confirmed the ubiquitous nature of microplastics on many beaches. To best of our knowledge, no previous study on microplastic pollution has been conducted in the present study area to date. This study examined the microplastic abundance, polymer type, size, shape and color in the sediments of Liuqinghewan Bathing Beach and the fishing port beach of Qingdao, China. Microplastics (1–0.5, 0.5–0.25 and 0.25–0.125 mm) were extracted from beach sediments using a density separation method. Fourier transform infrared (FTIR) spectroscopy was used to determine the chemical composition of the plastics while physical characteristics (size, shape, and color) of microplastics were observed using a stereomicroscope. The average microplastic abundance values with the grain size ranges from 1 to 0.125 mm at Liuqinghewan Bathing Beach and at the fishing port beach were approximately 208 ± 3.5 and 299 ± 5.7 microplastics per kg of dry sand, respectively. The number of microplastic particles with the grain size from 0.25 to 0.125 mm was significantly higher than for the other grain sizes. Microplastics were mainly multicolor fibers in all samples making up a large proportion that exceeded 97%. On the basis of FTIR analysis, the microplastics were shown to be composed of polypropylene and polystyrene at both sites. Microplastic characteristics used to identify their origin revealed high development and industrialization predict the non-point source of microplastics related to their hydrodynamic and geographical conditions. Assessing the distribution and characterization of microplastics on sandy beaches of some regions is not novel but a rather common study. However, the outcomes of current study furnish valuable and novel data for the evaluation of microplastic concentrations in beach sediments, environmental risks in China, and a baseline for future analysis.