Metal pollution source apportionment in two important Rivers of Eastern Cape Province, South Africa: a case study of Bizana and Mthatha Rivers

Regular monitoring of the chemical status of water bodies remains crucial in countries where data on chemical fingerprints that can assist in environmental policy is still limited. The current study focused on the concentrations of 14 metals and their sources in two important South African rivers that pass through various rural areas and two semi-urban towns in the province of the Eastern Cape. Most of the essential metals were within the South African guidelines for domestic water use except for selenium and iron which reached the concentrations of 131 and 712 µg L⁻¹ that exceed the guideline values of 20 and 200 µg L⁻¹, respectively. Cadmium and lead were above the South African Water Quality Guidelines and World Health Organization limits of 3 and 10 µg L⁻¹, attaining the highest concentrations of 35 and 34 µg L⁻¹, respectively. The impact of the wastewater treatment plant effluent and the municipal dumpsite leachates on metal ion concentrations in the rivers was observed for some metals. The metals source was related to deterioration of galvanized corrugated steel sheets from scrap yards and dwellings made-out of galvanized corrugated sheets, as well as agricultural activities and natural geological processes. An overview of the current water quality status of the two rivers may serve as a basis for sink-oriented pollutant fingerprinting toward sustainable water sources for communities.