Retinoids and endocrine disrupting chemicals in sewage treatment plants: removal efficiencies and ecological risks to marine organisms in a highly urbanized coastal city

Abstract

Marine environments of densely populated and urbanized coastal cities are often suffered from contamination of chemical pollutants such as retinoids (i.e., retinoic acids (RAs) and their metabolites) and endocrine disrupting chemicals (EDCs), which may pose ecological risks to marine organisms. In this study, we found that the sewage treatment processes in sewage treatment plants (STPs) of Hong Kong were not too efficient in removing total retinoids and EDCs from wastewater influents, with their average removal efficiency of 65% and 59%, respectively. Their removals were mainly attributed to sorption and degradation. With such limited removal, the effluents from STPs, and the adjacent seawaters (i.e., receiving water bodies) still exhibited elevated concentrations of retinoids and EDCs, which possessed medium ecological risks to the coastal marine ecosystem of Hong Kong (i.e., hazard quotients: 0.1–1).