Abundance, Composition and Distribution of Microplastics on Korean Beaches

Abstract

Microplastics are widespread and ubiquitous in the marine environment. Especially, beach is the most important location of microplastics accumulation. Contamination levels of microplastics in various marine compartments were widely reported in the world, but nationwide assessment of microplastic pollution was limited. Spatial distribution within a beach is not well addressed yet. Major factors influencing on pollution levels and spatiotemporal distribution of microplastics on beach are still unclear. Multiple lines across a beach (backshore B, strandline S, middle M, and water-edge W) and two seasons (before and after rainy seasons) were investigated to evaluate spatiotemporal distribution in twenty beaches along the coast of Korea in 2016. The relationship of microplastic abundance with environmental and potential source related factors influencing their spatial distribution were evaluated. The median value of microplastic abundances at each sampling line was in order of B > M > S > W. The mean abundance was significantly (Tukey HSD, p<0.05) higher in B line than M and W lines. Among 20 beaches investigated, B and S lines showed the highest abundance at 11 and 9 sites, respectively. Sampling of microplastics from only high strandline may overestimate microplastic pollution level or miss the hot spots near backshore. Therefore, multiple line or transect survey is required to obtain representing sample from a beac in the world, but nationwide assessment of microplastic pollution was limited. Spatial distribution within a beach is not well addressed yet. Major factors influencing on pollution levels and spatiotemporal distribution of microplastics on beach are still unclear. Multiple lines across a beach (backshore B, strandline S, middle M, and water-edge W) and two seasons (before and after rainy seasons) were investigated to evaluate spatiotemporal distribution in twenty beaches along the coast of Korea in 2016. The relationship of microplastic abundance with environmental and potential source related factors influencing their spatial distribution were evaluated. The median value of microplastic abundances at each sampling line was in order of B > M > S > W. The mean abundance was significantly (Tukey HSD, p<0.05) higher in B line than M and W lines. Among 20 beaches investigated, B and S lines showed the highest abundance at 11 and 9 sites, respectively. Sampling of microplastics from only high strandline may overestimate microplastic pollution level or miss the hot spots near backshore. Therefore, multiple line or transect survey is required to obtain representing sample from a beac