Dilution and dispersion of particulate matter from abandoned mine sites to nearby communities in Namibia

Abstract

In this study, the HYSPLIT model was used to model the dilution and dispersion of particulate matter in the surrounding of two abandoned mine sites (Klein Aub and Oamites) to the nearby communities. The simulations indicated a relationship between mass concentrations and meteorological parameters as well as their impacts on the dilution and dispersion of particulate matter. Dispersion simulations of the non-residential point indicated that the community of Klein Aub is mainly affected by tailings dust through the Easterly wind which transports tailings contaminated dust to the residential area during winter. Oamites dispersion simulations of the residential point located at 23°47′24.6 S; 016°38′46.2 E indicated that this point is not directly affected by the tailings dust. The results suggest that the influence of the wind direction and wind speed is more on the dispersion than dilution. The wind or lack of thereof can cause the particulate matter to move or accumulate around the pollution source. The dilution of particulate matter was mainly influence by the temperature, with generally low dilution observed in the cold winter months.