Assessment of microplastic contamination on beaches in South Korea

Abstract

The composition and distribution of microplastics in twelve beaches along Korean coast and six beaches of Geoje Island affected by riverine discharge from nearby Nakdong River were determined in 2012 and 2013-2014 respectively. On the beaches, ten quadrats (0.5 m x 0.5 m) were randomly placed along the high-stranded line and 1L sand passed through a 1 mm sieve was collected. In the laboratory, 50 mL sand from each 1L of ten quadrats was sub-sampled to make a composite sample (500 ml) representing each beach. The microplastics were separated with sediment using saturated NaCl solution. Supernatant was filtered through a 1.2 μm filter paper and plastic like particles on the filter papers were identified with a FT-IR microscope. The abundance of microplastics from eighteen beaches was in the range of 12-9,280 particle/L-sediment. The mean abundance of microplastics (< 1mm) from six beaches of Geoje (2,721 particles/L-sediment) was significantly (p<0.05) higher than those in others beaches (213 particles/L-sediment). The beaches in the East coast of Geoje Island were severely contaminated by microplastics. Among the five categories of microplastics (fragment, fiber, spherule, sheet and expanded polystyrene (EPS)), fragment type accounted for the highest portion (50-100%) in the 12 beaches, while in Gangneung, the highest portion was fiber (50%) and in 5 beaches were EPS (49-100%). In polymer composition, polypropylene, es, ten quadrats (0.5 m x 0.5 m) were randomly placed along the high-stranded line and 1L sand passed through a 1 mm sieve was collected. In the laboratory, 50 mL sand from each 1L of ten quadrats was sub-sampled to make a composite sample (500 ml) representing each beach. The microplastics were separated with sediment using saturated NaCl solution. Supernatant was filtered through a 1.2 μm filter paper and plastic like particles on the filter papers were identified with a FT-IR microscope. The abundance of microplastics from eighteen beaches was in the range of 12-9,280 particle/L-sediment. The mean abundance of microplastics (< 1mm) from six beaches of Geoje (2,721 particles/L-sediment) was significantly (p<0.05) higher than those in others beaches (213 particles/L-sediment). The beaches in the East coast of Geoje Island were severely contaminated by microplastics. Among the five categories of microplastics (fragment, fiber, spherule, sheet and expanded polystyrene (EPS)), fragment type accounted for the highest portion (50-100%) in the 12 beaches, while in Gangneung, the highest portion was fiber (50%) and in 5 beaches were EPS (49-100%). In polymer composition, polypropylene,