Impact of Atmospheric Deposition on Surface Water Runoff of Toxic Chemicals in Urban Environment

Abstract

Pollutants loading from non-point and diffuse sources can be the most significant in a watershed. Atmospheric deposition in its three forms (ambient, dry, and wet) have been neglected and thus was not included in watershed approach to water resources management. Often regulatory frameworks for water resources protection have not taken into account atmospheric deposition because little or no data is available. The project undertaken is new and unique in its scope and approach to monitor and measure pollutants in atmospheric deposition and its impact on storm water quality.Specialized sampling equipment and ultra-clean analytical methodology were employed to quantify the concentrations or fluxes of mercury (Hg), cadmium (Cd) and polychlorinated biphenyls (PCBs) in ambient air, precipitation, and runoff. The relationship between the atmospheric deposition and runoff on controlled surfaces was explored for the three pollutants, and the impact of the atmospheric deposition to the toxic chemical loading in runoff was investigated. Atmospheric deposition was found to be the primary mass source of Cd, Hg, and PCBs in runoff from the controlled surfaces.