The Source of Parabens in Urban River Water: The Evidence From Outdoor Multimedia Environment in Six Metropolitan Cities, China

Parabens (PBs) are typical endocrine disrupting compounds (EDCs) that are commonly found in a water environment. However, their fate and transport in urban rivers remain largely unexplored. This study offers a quantitative analysis of the sources of PBs in urban river water, considering the perspective of a multimedia environment. PBs were ubiquitous in the surface water of six metropolitan cities in China, with median concentrations of 8.38 ng/L. A significant difference was observed for PB concentrations in different cities. The geographical variation of PBs in the six rivers may be influenced by multiple factors, including hydrological conditions (runoff amounts and catchment areas), environmental factors (temperature and SPM concentrations), population density, production, and domestic wastewater discharge. Here, the occurrence of PBs in outdoor dust was reported for the first time and was found to be the most polluted solid medium on the land surface. The estimated input fluxes of PBs in the six rivers ranged from 32.0 to 1470 tons/a. The point source emission was the primary input source of PBs in river water of the six cities, contributing between 56.7% and 93.7%, followed by the non-point source discharge of runoff scouring dust, contributing 1.77% to 38.4%.