Heavy metals contamination of sedimentary microplastics in Hong Kong

This is the first study of heavy metals (As, Zn, Cd, Ni, Fe, Mn, Cu) contamination of microplastics on sandy beaches in Hong Kong. Three study sites are located in the eastern waters (Pak Lap Wan, Stanley Bay, Tung Lung Chau) and the other three in the western waters (Tai Pai Tsui, Ha Pak Nai, Shui Hau Wan). The three most abundant types of microplastics were polyethylene (42.2%), polypropylene (23.3%) and polystyrene (19.5%). The median concentration of Fe (302 mg kg^-1) was the highest and followed by Zn (19.6 mg kg^-1) and Mn (18.6 mg kg^-1). Very low concentrations of Cu (0.89 mg kg^-1), Ni (0.15 mg kg^-1), As (