Assessment of the phytoremediation potential of indigenous plant species for lead-contaminated soils in the Tiira artisanal gold mining zone, Busia district, Uganda.
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Date
2026
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Busitema University
Abstract
Lead contamination associated with artisanal and small-scale gold mining (ASGM) poses a significant environmental and public health concern because of the persistence, toxicity and potential mobility of Pb in contaminated soils. In Busia District, Uganda, mining activities have contributed to the degradation of soils and may increase the potential for Pb transfer to surrounding ecosystems and communities dependent on land resources. Conventional remediation approaches, including soil excavation and chemical stabilization, can be costly, disruptive and difficult to implement in resource-limited settings (Evanko et al., 1997). Phytoremediation therefore provides a potentially sustainable and locally adaptable approach for managing contaminated soils. This study assessed the phytoremediation potential of indigenous plant species naturally growing in Pb-contaminated soils within the Tiira artisanal gold mining zone, Busia District, Uganda. The specific objectives were to determine Pb concentrations in contaminated soil, identify indigenous plant species occurring naturally within the contaminated environment, and evaluate their Pb uptake and accumulation capacity. Soil and whole-plant samples of Ageratum conyzoides, Bidens pilosa, Amaranthus spinosus and Galinsoga parviflora were analysed following wet acid digestion, and Pb concentrations were determined using UV–Visible spectrophotometry. The soil contained 949 mg kg-1 Pb, approximately 9.5 times the adopted WHO/FAO guideline value of 100 mg kg-1, confirming substantial Pb contamination. Pb accumulation varied among the investigated species, with A. conyzoides recording the highest concentration (846 mg kg-1) and BAF (0.89), followed by B. pilosa (692 mg kg-1; BAF = 0.73), A. spinosus (513 mg kg-1; BAF = 0.54) and G. parviflora (256 mg kg-1; BAF = 0.27). None of the species recorded a BAF greater than one. A. conyzoides and B. pilosa therefore demonstrated the greatest Pb accumulation potential among the investigated indigenous species and warrant further evaluation in long-term phytoremediation studies. The findings provide baseline evidence supporting the use of locally adapted vegetation in the management of mining-contaminated soils and contribute to sustainable approaches to environmental restoration, responsible land management and community protection. The study is relevant to the Sustainable Development Goals, particularly SDG 3 (Good Health and Well-being), SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), SDG 15 (Life on Land) and SDG 13 (Climate Action), through its contribution to pollution reduction, ecosystem restoration and sustainable environmental management.
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Undergraduate research report
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Bwire, D. W. (2026). Assessment of the phytoremediation potential of indigenous plant species for lead-contaminated soils in the Tiira artisanal gold mining zone, Busia district, Uganda. [Unpublished undergraduate research report]. Busitema University.