Development of a health risk management framework for heavy metals and cyanide in Kwekwe City, Zimbabwe
Background: Globally, humans are constantly exposed to numerous environmental pollutants and suffer from acute and chronic conditions. Pollutants, such as heavy metals and cyanide cause various health conditions which impair public health. Aim: This study aimed to develop a health risk management framework for heavy metal and cyanide pollutants in Kwekwe City. Methods: The convergent parallel mixed-method study design was utilised. The systematic literature review identified and described key characteristics and elements of risk management frameworks guided by the Organisation for Economic Co o peration and Development principles. A cross-sectional exploratory qualitative study was conducted on purposively selected key stakeholders and industrial settlement residents. Unstructured interviews and focus group discussions were used to gather data on perceived heavy metals and cyanide risks. The data were transcribed verbatim, translated into English, coded, and thematically analysed using R-Software. A quantitative cross-sectional study was conducted to determine levels of heavy metals in the surface water, soil, and vegetables. Grab samples were analysed using the US EPA 3050b method to determine concentrations of heavy metals. Free cyanide was determined only in surface water samples. Statistical data analysis was done using R-Software in the quantitative study. The US EPA method was used to estimate the health risks of potentially toxic elements and cyanide. Results: The qualitative study on heavy metal and cyanide risk perceptions identified five main and fifteen sub-themes that emerged from the data analysis. Participants perceived that environmental pollution posed significant health risks in the area that were principally linked to cyanide, mercury, and chromium. Iron, zinc, lead, and cyanide were the main pollutants in the quantitative enquiry. Cyanide and iron contributed the most to the hazard index and non-cancer risks. The combined qualitative and quantitative data were analysed, compared, and merged to inform the development of a risk management framework. The developed framework was validated through stakeholder consultation and the Delphi Technique. Conclusions: Residents perceived heavy metal and cyanide pollutants as public health risks. The level of pollutants and associated health risks indicated the existence of a problem, which was leveraged to develop a risk management framework.
Cancer risk, Delphi technique, Health risk, Kwekwe, Mixed method study, Potentially toxic metal, Purposive sampling
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