Comprehensive sub-chronic toxicological profiling of illegal artisanal small-scale mining-polluted river bodies in four regions of Ghana

Authors: Du-Bois Asante, George Yaw Hadzi, Samuel Naaman, Michael Woode, Timothy Makwo, Benjamin Aboagye, Isaac Tabiri Henneh

Abstract:

Illegal artisanal mining, or ‘Galamsey’, in Ghana poses serious public health risks by contaminating water bodies with toxic heavy metals. This study assessed the sub-chronic toxicological effects of mining-polluted rivers in four Ghanaian regions using rats as an experimental model. A 90-day sub-chronic toxicity test was conducted using water samples from four regions associated with mining-polluted rivers: Bonsa, Birim, Nyam, and Subiri. Heavy metal analysis was conducted on the sampled water from these selected illegal mining-prone rivers. Rats were divided into six groups: two controls (distilled water and pristine river) and four treatment groups (contaminated water from the four rivers). Rats were given 2 mL of water from each water source for 90 days. Blood samples were analyzed for hormonal, hematological, and several biochemical markers. Fasting blood sugar, urine, and semen analyses were also performed. Rats were euthanized, and organs were harvested for histopathological analysis. Lead was significantly elevated in all mining-polluted rivers when compared to the controls. Exposed groups showed significant weight loss, elevated serum creatinine kinase (CK-Nac), and the presence of WBC, RBC, crystals, and casts during urinalysis. Haematological profiles indicated erythrocytosis and immune variations. Serum biochemical parameters, such as AST, ALP, and ALT, were significantly elevated (p < 0.05), and sperm counts were significantly reduced (p < 0.05) in the exposed groups. Histopathology revealed non-caseating granulomas, necrosis, and leucocytosis in the liver and lungs, as well as pronounced hemosiderosis in the spleen. Histopathology of renal and testicular organs revealed necrotic tissue and degenerative cellular changes.

Gap addressed:

Although several studies in Ghana have assessed the soil and water quality at galamsey sites, with some estimating the varied concentrations of heavy metals and their potential health effects, the systemic toxic effects of galamsey and unregulated small-scale mining-contaminated water on terrestrial organisms, particularly mammals, are yet to be investigated. Ultimately, these speculations further present the need to experimentally assess the potential toxic effects of galamsey and unregulated small-scale mining-contaminated rivers using rats as experimental models.

Sector/Industry focus:

Environmental and mining sector
Ghana water works
Health sector

Potential uptake or practical application:

These results suggest that illegal mining-related water contamination in Ghana presents severe health risks, demonstrating its severe haematotoxic, nephrotoxic, hepatotoxic, pulmonotoxic, myotoxicity, and reproductive toxicity in the experimental rat models.

Key recommendations:

Implementation of stringent policies is therefore needed as this does not only affect systemic toxicology but also carries profound implications for the broader fields of environmental toxicology and public health. By bridging the gap between environmental degradation and its ramifications on terrestrial organisms, including humans, this current study underscores the urgent need for effective environmental management and regulation in galamsey and unregulated small-scale mining-prone regions, while contributing to the collective effort to safeguard ecosystems and human health globally. This, therefore, calls for strict regulatory measures to be implemented regarding the practice of illegal mining and cessation of the spillage of heavy metals into nearby water bodies.