Spatial and temporal trends of anthropogenic pollutants in a tropical, urban environment in east Africa

A range of chemicals which are potentially harmful to human health and the environment are used in industrial and consumer products including electronics. Source regions for such pollutants to the environment may be shifting from the Global North to the Global South given e.g., trade in products and waste and lacking capacity for environmentally sound waste handling. However, there are large knowledge gaps concerning the occurrence and fate of these chemicals in the Global South. In this work, occurrence, distribution, sources, and time trends of both legacy and emerging chemical pollutants were investigated in and around Dar es Salaam, Tanzania. This was done by analysis of samples from air and soil, and a dated sediment core. The results from the dated sediment core showed increasing levels of legacy chemical pollutants in the late 2010s. This suggests that international regulation has not yet been effective in lowering environmental burdens of these pollutants in Dar es Salaam. Levels of some emerging chemical pollutants were documented to increase dramatically in the late 2010s. Spatial trends of these emerging chemical pollutants in air and soil in the studied region suggests handling of both general waste and electronic waste are important sources.