Recent research reveals alarming levels of mercury and arsenic in fish from Ghana’s Keta Lagoon. This contamination poses cancer risks, especially to children consuming local fish. The study marks urgent environmental and public health concerns demanding immediate attention.
Background of Keta Lagoon
Keta Lagoon is Ghana’s largest lagoon complex and a Ramsar wetland site. It is separated from the Gulf of Guinea by a sandbar, limiting water exchange. This closed nature causes pollutants to accumulate in the lagoon’s sediments and water, increasing contamination risks.
Study Findings on Heavy Metal Levels
Researchers analysed 12 fish samples from various parts of the lagoon. They found arsenic in 75% of samples exceeded the World Health Organization (WHO) safety limit of 2 mg/kg. Mercury levels were nearly three times higher than the WHO limit of 0.5 mg/kg in all samples. Cadmium surpassed limits in two samples. Chromium, lead, and zinc remained mostly within safe ranges but showed variability linked to industrial and agricultural runoff.
Health Risks from Metal Exposure
The study assessed cancer and non-cancer risks using standard risk models. Arsenic, mercury, and chromium were identified as the most dangerous metals. All metals except cadmium posed long-term cancer risks to children. Adults and children both face non-carcinogenic risks, with children more vulnerable due to lower body weight and higher absorption rates. The Target Hazard Quotient (THQ) for arsenic, mercury, and chromium exceeded safe thresholds in adults and children, signalling potential health hazards.
Bioaccumulation in Fish and Human Impact
Sediment-feeding fish tend to accumulate heavy metals over time. This makes them reliable indicators of aquatic pollution. Fish are a vital protein source for millions of local residents. Consuming contaminated fish increases exposure to toxic metals, raising cancer and other health risks. Children’s greater susceptibility makes this a pressing public health issue.
Environmental and Regulatory Implications
The study points to industrial and agricultural pollution as key contributors to heavy metal contamination. Limited water flow in the lagoon worsens pollutant buildup. Researchers call for stricter pollution controls and enhanced environmental monitoring. Public health campaigns are essential to educate communities relying on lagoon fish. Despite the study’s small sample size, its findings demand urgent action from Ghanaian authorities.
Recommendations for Mitigation
Authorities should enforce regulations to reduce industrial and agricultural runoff. Continuous monitoring of heavy metals in fish and water is critical. Public awareness programmes must inform about the risks of consuming contaminated fish. Alternative protein sources should be promoted to reduce dependency on lagoon fish. These steps are vital to protect vulnerable populations, especially children.
Questions for UPSC:
- Critically discuss the impact of industrial pollution on aquatic ecosystems and human health in developing countries.
- Analyse the role of wetland ecosystems like Ramsar sites in biodiversity conservation and pollution control.
- Examine the challenges of regulating heavy metal contamination in water bodies. How can policy interventions improve public health outcomes?
- Estimate the socio-economic effects of environmental pollution on fishing communities and suggest sustainable livelihood alternatives.
