Horizontal and vertical distribution of phthalates acid ester (PAEs) in seawater and sediment of East China Sea and Korean South Sea: Traces of plastic debris?

Phthalate acid esters (PAEs) are commonly used as plasticizers in numerous plastic applications. Owing to their high leachability, the occurrence of PAEs can be used to trace plastic pollution. The northwest Pacific marginal seas, including the East China Sea, are suspected not only to be the area that receives the most plastic waste globally but also transit the waste to the ocean worldwide. To identify the potential sources of PAEs in this area, seawater at different water depths and sediment were investigated. The highest level of di(2-ethylhexyl) phthalate (DEHP), which is primarily used in plastic polymers, was observed in the accumulation zone of plastic debris. Moreover, DEHP exhibited not only the highest levels in the bottom layer of water column but also a significant correlation between bottom water layer and bed sediment, which strongly suggests a continuous flow of PAEs from the seafloor to the seawater column in this area.