The contribution of dioxin-like compounds from platinum mining and processing samples

Dioxin-like compounds including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are polyhalogenated aromatic hydrocarbons (PHAHs) that bio-concentrate, bio-accumulate and bio-magnify because of their hydrophobicity, and persistence in the environment. These compounds are formed as a result of incomplete combustion during certain industrial and thermal processes (smelting of metals). Because non-ferrous metal production is a known source of dioxin-like compounds, a platinum mine in the Limpopo Province, South Africa was studied to determine if it was a possible source. Woodchip samples, as well as samples from the tailings dams, the slag and the dumpsite, were collected, extracted and the dioxin load determined by a bio-assay. Slag from the smelter contributed to the highest dioxin formation (61%), and a more in-depth investigation of the smelting process is suggested.