Unseen streams tracing emerging contaminants from stormwater to surface water: A brief review

Abstract

Emerging contaminants (ECs) have raised global concern due to their adverse effect on ecosystems and human health. However, the occurrence and transport of ECs in stormwater remain unclear. The impact of ECs from stormwater on surface water quality and ecosystem health is also poorly documented. In this review, we examined the variations in EC concentrations in surface water resulting from stormwater. During the wet weather, the concentrations of most investigated ECs, e.g., microplastics, per- and polyfluoroalkyl substances, and vehicle-related compounds, significantly increase in surface water, indicating that stormwater may be a critical source of these contaminants. Furthermore, the potential pathways of ECs from stormwater enter surface water are outlined. Studies demonstrate that surface runoff and combined sewer overflows are important pathways for ECs, with discharges comparable to or exceeding those from wastewater treatment plants. Illicit connection also plays an important part in elevated EC concentrations in surface water. Overall, our findings underscore the importance of stormwater as a source for ECs in surface waters, and urge for increased emphasis on, and reinforcement of, stormwater monitoring and control measures to minimize the transport of ECs into receiving water bodies.