Multimedia distribution and bioaccumulation of methylsiloxanes in industrialized bays of Korea

Abstract

Siloxanes are compounds that are widely used in numerous consumer and industrial applications due to their chemical inertness, soft texture, low surface tension, and high thermal stability, and they are found in various environments. Previous studies have reported that siloxanes are contaminants of emerging concerns in the environments. Despite this, little studies have been conducted on the distribution, time trends, and bioaccumulation of siloxanes in multiple environmental matrices. In this study, siloxanes were analyzed in water, sediments, and organisms collected from industrialized bays (Ulsan and Onsan Bays) to investigate contamination, spatial distribution, time trends, and bioaccumulation potential. Two fluorinated siloxanes (D3F and D4F), four cyclic siloxanes, and 15 linear siloxanes were measured in multiple environmental matrices. D3F and D4F were not detected in any samples. Cyclic siloxanes were the predominant compounds in all matrices, with detection frequency ranging from 63% to 98% across all matrices. This indicates widespread contamination by siloxanes in Korean coastal waters. The highest concentrations of siloxanes were observed in locations near a variety of industrial complexes, such as petrochemical, chemical fertilizer, and automobile industries, suggesting the potential sources of siloxane contamination. Different accumulation patterns of siloxanes were observed for fish and mollusks, implying species-specific accumulation. The results of bioaccumulation factor (BAF) and biota-sediment accumulation factor (BSAF) showed the potential for accumulation in biota for almost all siloxanes. Trophic magnification factor (TMF) showed increasing trends with increasing molecular weight of siloxanes. The concentrations of D4 and D5 measured in water were below thresholds, whereas some sediments showed the exceeding values for thresholds proposed by previous studies. This study suggests the continuous monitoring studies to assess the potential health risks associated with siloxane contamination in Korean coastal waters.