Emerging contaminants in municipal wastewaters and their relevance for the surface water contamination in the tropical coastal city Haikou, China

Abstract

Wastewater treatment plants in large urban agglomerations are worldwide among the main sources of emerging contaminants in aquatic systems. The present study is a first comprehensive characterization of potentially harmful emerging contaminants in sewage of a Chinese urban area. The study area Haikou City is located at the coast of tropical Hainan Island. A GC/MS based non-target screening approach for the identification of a wider range of lipophilic to semi-polar organic sewage constituents was applied. Pollution originating from sewage was tracked in the urban coastal waters by using selected source-specific indicators.A set of sewage constituents with a high structural diversity was identified comprising both, industrial and household chemicals. Ingredients of personal care products, pesticides and pharmaceuticals were found, that were rarely reported from other regions of the world. This observation might be attributed to different environmental legislation and consumption habits in China. Exceptionally high concentrations of the illegal drug ketamine with up to 1100 ng L−1 were detected, suggesting its high popularity and consumption rate. Noteworthy, sewage constituents reported here for the first time were the pharmaceuticals marmesin, oxolamine and ansimar also with high concentrations of up to 1200 ng L−1.Elevated concentrations of sewage indicators in the main city area suggest the overflow of the sewage system, in particular in the period of a typhoon event. Tracing the sewage contamination in the surface water system of the coastal urban area of Haikou revealed a lower level of pollution. The concentration ranges point to no acute risks for the coastal ecosystem due to sewage inputs from the city area.Generally, the detected spectrum of municipal emerging contaminants has to be considered for the testing and technical improvement of wastewater treatment techniques, for regular monitoring of the surface water quality and for environmental impact assessment in China. Furthermore, the compound spectrum reported here is a good reference point for the composition of municipal sewage in other emerging economies.