Effect of physico-chemical properties of road deposit sediments on BTEX accumulation

Abstract

Few studies have investigated on accumulation of benzene series pollutants (benzene, toluene, ethylbenzene and xylene, BTEX) on urban road surfaces as well as the relationship between BTEX accumulation and physio-chemical properties of road deposit sediment particles. In this paper, seventeen typical urban road sites in Henggang Street of Longgang District, Shenzhen city, were selected to analyze BTEX loads. These selected road sites covered different urban functional districts (commercial, industrial and residential) and different road types (common roads and road junctions). The accumulated particle samples were collected on the selected roads using a dry and wet vacuuming method and these samples were tested for BTEXs by a gas chromatography-mass spectrometer. The physico-chemical properties of particles such as particle size distribution, mineral content and chemical oxygen demand (COD) were tested. The effect of the cumulative load of BTEX particles on physical and chemical properties of particles was analyzed by using principal component analysis (PCA). The results indicate that build-up loads of BTEXs with particles size <150 μm are higher than those of BTEX particles with particle size > 150 μm; quartz is the main mineral in all particles with different particle sizes; the COD loads attached on fine particles are much higher than those on coarse particles; berlinite could be an important carrier of BTEXs on road surfaces. These results can provide useful insights to ensure stormwater reuse safety and safeguard urban water environment.