Distribution patterns and transportation behavior of alkylphenol polyethoxylate degradation metabolites among river, port area, and coastal water bodies of Kaohsiung City, Taiwan

Abstract

In this study, we conducted a comprehensive study of the distribution, transportation behavior and potential ecological risk of alkylphenol polyethoxylates (APnEOs) in the aquatic environments of Kaohsiung City, Taiwan because little information is available regarding the fate of APnEOs in the water bodies of a total environment. At Love River, APnEOs concentrations were much higher at upstream of interception stations L15 (27.33 ± 1.22 μg/L) and L16 (6.31 ± 0.14 μg/L) than at downstream of interception stations L1–L14 (0.69–2.54 μg/L). Additionally, the average ethoxy (EO) chain lengths of APnEOs at L15 and L16 were longer than at L1–L14. These observations were attributed to the sluice between L14 and L15 that intercepts and accumulates untreated sewage from upstream areas and to the infrastructure of the sewage system that prevents domestic sewage from flowing downstream in the river and to the Kaohsiung Port Area. At Kaohsiung Port Area, APnEO concentrations ranging from 0.63 to 6.50 μg/L were measured. The concentration range and average EO chain length of these APnEOs were similar to those of the downstream stretch of the river, which was attributed to the mixing efficiency of the Kaohsiung Port Area and Love River through tidal exchange. At Cijin Coastal Area, APnEO concentrations ranged from 0.14 to 18.77 μg/L. Notably, the APnEO concentration of surface waters was much higher than that of bottom waters. This observation was attributed to the sewage discharged from the ocean outfall buoying up to the surface instead of mixing with surrounding bottom waters. In potential ecological risk, 19 of 39 sampling points exceeded toxic equivalency of 1 μg/L, and approximately 48.7% of the sampling points would exceed the threshold. The result provides insight into the environmental implications of APnEOs contamination in aquatic environments and useful information for environmental policy and ecological risk assessments.