Contamination characteristics of siloxanes in coastal sediment collected from industrialized bays in South Korea.

Siloxanes have been used as chemical additives in various products since the 1940s. They are known to have potentially toxic effects, to be environmentally persistent, and to be bioaccumulative. Previous studies have reported high levels of siloxanes in various environmental matrices. In this study, 6 cyclic siloxanes (D4-D9) and 13 linear siloxanes (L3-L15) in coastal sediment collected from southeastern bays adjacent to industrial zones in South Korea (Busan, Ulsan, Jinhae, and Gwangyang) were analyzed. The contamination levels and spatial distribution of siloxanes in the coastal sediment samples were investigated, with the hazard quotients (HQs) for siloxanes evaluated using Monte Carlo simulation. Across all samples, the total concentration (Σ19) of siloxanes was in the range of 11.6-3877 (mean: 305; median: 133) ng/g dry weight (dw). The highest average concentration of Σ19 siloxanes was found in Busan (mean: 580; median: 233 ng/g dw), followed by Ulsan (mean: 316; median: 209 ng/g dw), Jinhae (mean: 266; median: 125 ng/g dw), and Gwangyang (mean: 33; median: 27 ng/g dw), all of which are suggested to be affected by both industrial and domestic activities. The highest contributions were from D5 (18%) and D6 (34%), followed by D9 (7.3%) and L11 (5.8%). The HQs for siloxanes were less than 1, indicating that there was no risk to benthic organisms in the study areas; however, further monitoring of various environmental matrices is required to fully assess the potential ecological risks.