Characteristics of pollutants built-up on residential road surfaces

Abstract

Pollution build-up in relation to urban stormwater quality is one of the most important pollutant processes that need in-depth investigation. Build-up varies with range of climatic, land-use and regional parameters and illustrates a highly dynamic nature. This paper presents the outcomes of an in-depth investigation into pollutant build-up on typical residential urban road surfaces. The outcomes of the investigation revealed highly site specific rates of build-up that primarily varied with road surface conditions, traffic volume and surrounding land-use. The rate of build-up was initially in the range of 1 to 2g/m2/day and decreased when the antecedent dry days increased. The total build-up varied from site to site but did not exceed 6g/m2. This amount was significantly less compared to numerous previous research studies. It was further noted that particulate pollutant composition varied dynamically when the antecedent dry days increased. It is hypothesised that this is due to the re-distribution of finer particles by the wind and traffic. Analysis of quality parameters revealed that a higher fraction of pollutants is associated with the finer particle size ranges. Furthermore, a relatively high amount of dissolved organic carbon was detected in build-up samples during the study. Dissolved organic carbon enhances the solubility of other pollutants such as heavy metals and hydrocarbons thus increasing their bio-availability.