Spatial distribution of bulk atmospheric deposition of heavy metals in metropolitan Sydney, Australia

The detailed spatial distribution of atmospheric deposition flux of pollutants in metropolitan Sydney, Australia (ca. 480 km²) is investigated through the direct simultaneous sampling of bulk deposition adjacent to roads with various traffic volumes and at background sites over a period of 1 year. Based on the field results and detailed land-use analyses, atmospheric deposition rates of copper, lead and zinc are calculated for the metropolitan region, and the contributions to stormwater pollutant loads are evaluated. Total particulates and heavy metals in bulk atmospheric deposition are found to be temporally consistent, and to exhibit strong correlations with road proximity and traffic volume. The material captured adjacent to major roads has a distinct average composition of 862 mg/kg copper, 364 mg/kg lead and 4,617 mg/kg zinc. Modelling accounting for road proximity, traffic volume and land-use affords annualised stormwater-entrainable depositional fluxes of 6.5, 4.1, 47.2 and 10,800 kg/km²/year for copper, lead and zinc.