Assessment of Heavy Metal Contamination and Demographic Characteristics of Fish Consumers around Lake Geriyo, Adamawa State, Nigeria

Background and Objective: Lake Geriyo, Yola, is an important inland fishery that supports livelihoods and food security for surrounding communities. Increasing anthropogenic activities have led to possible contamination by heavy metals, raising concerns about public health impacts on local fish consumers. The main aim of this research was to assess the demographic characteristics of fish consumers around Lake Geriyo and determine the concentrations of selected heavy metals in their blood to evaluate potential health risks. The study sought to identify demographic patterns among fish consumers, quantify Fe, Mn, Zn, Cu, Cd, and Pb levels in human blood, and examine how gender, age, and occupation influence metal exposure. Materials and Methods: Blood samples from 100 adults (18-66 years) were collected in EDTA bottles under ethical approval and stored under refrigeration. Heavy metals were analyzed using Flame Atomic Absorption Spectrophotometry after standard digestion with triplicate analysis. Data were expressed as mean±SD and analyzed using descriptive statistics at p<0.05 significance level. Results: Cadmium and lead were not detected in any samples, while iron (Fe) and manganese (Mn) showed the highest mean concentrations in human blood (Fe = 7.64±3.21 mg/L in males; Mn = 0.62±0.27 mg/L). Although no significant gender or age differences were found for most metals (p>0.05), manganese varied significantly between males and females (p = 0.05). Fishermen exhibited the highest concentrations due to direct contact with lake water and fish. Conclusion: The results demonstrate that fish consumers around Lake Geriyo are exposed to elevated levels of iron and manganese, potentially increasing the risk of health complications. Continuous monitoring and community education are recommended to mitigate further contamination.