NovelWater Quality Index (Novel WQI) for the Assessment ofWater Body Pollution in a Semi-Arid Gold Mining Area (Bam Province, Burkina Faso)

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Résumé

Since the 2000s, Burkina Faso has experienced a rapid mining expansion with more than
one hundred sites established, leading to increased waste generation often discharged
untreated into the environment. Assessing water quality in these areas is therefore critical
to mitigate environmental degradation and public health risks. This study develops a
site-specific water quality index (WQI) for a gold mining area in Bam Province, Burkina
Faso, with the objective of improving pollution monitoring and management in relation
to tailing dams. Surface and groundwater samples were collected between 2021 and
2024. Physico-chemical and bacteriological analyses of groundwater sources including
wells, piezometers and boreholes revealed that several parameters such as pH, turbidity,
nitrates, sulphates, total iron, aluminium, arsenic, cadmium, cyanide and total and faecal
coliforms exceeded international drinking water standards. Geospatial techniques were
employed to identify the main contamination sources: domestic wastewater, industrial and
artisanal mining and agricultural runoff. The evolution of these parameters in relation to
the dynamics of soil occupation and the influence of geological structure has enabled the
distinction of key parameters associated with discharges. Although individual contaminant
levels were mostly moderate, their combined effects pose a significant long-term risk to
ecosystems and human health. The tailored WQI is suitable for both surface water and
groundwater. It provides an integrated tool for classifying and monitoring water quality in
mining environments, supporting evidence-based decision making in the management of
tailing dams, environmental protection and public health.

Mots-clés

hydrogeochemical assessment; groundwater contamination; water quality index (WQI); mining-induced pollution; gold mining