Occurrence, spatial distribution, and historical trend of phthalates and non-phthalate plasticizers in sediment from semi-enclosed bays, Korea

Abstract

Phthalates (PHTHs) have been widely used as plasticizers in commercial industrial products. The occurrence of PHTHs in marine environment is of great concern due to their adverse health effects to aquatic organisms and humans via seafood. Based on domestic and global regulations on PHTHs in certain products, these contaminants have been replaced by non-phthalates plasticizers (NPPs). However, limited data is available on the occurrence and environmental fate of PHTHs and NPPs in coastal environments. In this study, 16 phthalates and five NPPs were measured in 54 surface sediments and 3 dated sediments from Masan Bay in Korea. The sediment samples were analyzed by a gas chromatography coupled to triple quadrupole mass spectrometer with optimized solid phase extraction method. The highly detected compounds in all sediment samples were dimethyl phthalate (DMP), di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP), di(2-ethylhexyl) adipate (DEHA), acetyl tri-n-butyl citrate (ATBC), and tris (2-ethylhexyl) trimellitate (TOTM), indicating widely consumed in Korea. The total concentrations of PHTH and NPPs in all sediment ranged from 47.5 to 246200 (mean: 10000) ng/g dry weight and 27.7 to 3440 (770) ng/g dry weight, respectively. Higher-molecular-weight PHTHs such as DiNP, DEHP, and DIDP showed the highest concentrations due to their higher consumption and octanol-water partitioning coefficient (Kow). The highest concentration of NPPs was found for TOTM, indicating an emerging contaminant in coastal environment. The overall distribution of PHTHs and NPPs in sediment showed the decreasing gradient from inner to outer part of the bay, suggesting the influence by anthropogenic activities. A clear decreasing trends in concentrations of PHTHs and NPPs in sediment from the outfall of a wastewater treatment plant (WWTP), implying contamination sources of these contaminants from WWTP activities. Sediment core with different sources had the highest concentrations in the sediment core 2 located in front of the WWTP, the second highest in the sediment core 1 affected by the industrial complex, and the lowest in the sediment core 3 affected by the residential area. Increasing trends in phthalates in dated sediments were found after 1970s and then decreased to 2000s. Due to the regulation effect for phthalates after industrialization of Korea. Our findings highlight the necessity of ecotoxicological survey associated with the exposure of phthalates and their alternatives to living organisms in aquatic environment.