Caractéristiques physico-chimiques des eaux et sédiments des sites d’exploitation artisanale de l’or dans le territoire de watsa (République Démocratique du Congo)
Keywords:
Physicochemical characteristics, Degradation, Artisanal gold mining, Watsa, CorrelationAbstract
Artisanal gold mining intensifies environmental degradation and threatens human health by altering the physicochemical characteristics of
environmental compartments. This study evaluated the physicochemical properties of river water, spring water, and associated sediments
collected from artisanal gold mining sites in the Watsa Territory, Democratic Republic of Congo. A total of 20 water and sediment samples
were collected and analyzed. In situ measurements included pH, oxidation-reduction potential (Eh), electrical conductivity (EC), salinity, and
total dissolved solids (TDS), while laboratory analyses determined calcium (Ca), magnesium (Mg), chloride (Cl⁻), organic matter (OM), and
moisture content using standardized methods. River water (pH 5.25 ± 0.66; Eh 580 ± 10 mV) and spring water (pH 5.48 ± 0.06; Eh 580 ± 20
mV) exhibited acidic conditions and elevated redox potential. Sediments showed higher EC values (27.6 ± 26.1–54.2 ± 2.5 µS/cm) than water
samples. Major ionG concentrations (Ca, Mg, and Cl⁻) remained generally low (<60 mg/L), although they were comparatively higher in water
than in sediments. Several physicochemical parameters exceeded World Health Organization guideline values, indicating deterioration of
environmental quality and potential health risks associated with artisanal mining. Principal Component Analysis (PCA) identified Eh, chloride,
EC, and salinity as the most representative and positively correlated variables, explaining 88.2% of the total variance. The first principal
component (PC1) represented the redox gradient, demonstrating that oxidation-reduction processes are the dominant factors governing
physicochemical variability across the investigated mining environments and surrounding ecosystems.
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