Modelling benzene series pollutants (BTEX) build-up loads on urban roads and their human health risks: Implications for stormwater reuse safety

Benzene series compounds (BTEX) are toxic pollutants primarily generated by traffic activities in an urban environment. BTEX pollutants can be deposited (build-up) on urban road surfaces during dry periods and then washed-off into stormwater runoff. Since BTEX pollutants can pose high human health risks, they can undermine stormwater reuse safety after they enter stormwater runoff. In this study, the BTEX pollutants build-up loads on urban road surfaces were investigated in Shenzhen, China. An artificial neural network (ANN) approach and two conventional regression modelling approaches were compared in terms of estimating BTEX build-up loads based on land use related parameters. It was found that the ANN approach had a better performance than the two regression modelling approaches. Additionally, the spatial distribution maps and human health risk map of BTEX pollutants build-up created using the ANN approach can provide a robust visualization platform to identify 'hot spot' areas. These areas have a potential to generate highly BTEX polluted stormwater runoff and hence be inappropriate to be reused. These research outcomes are expected to provide an effective approach for ensuring stormwater reuse safety and a useful guidance for decision-making for stormwater management and water environment protection related urban planning.