Correlates of Food Contamination by Heavy Metals in Northwest Nigeria

Background: The increasing cases of chronic kidney disease is a global public health concern. The potential link between consumption of food contaminated with heavy metals and development of end stage renal disease is becoming an emerging challenge. This study aimed to identify heavy metal contaminants in food and environmental risk factors for development of chronic kidney disease in Nigeria.

Methods: Cross-sectional survey in 4 high burden local government areas of Jigawa state, northwest Nigeria.

Results: The median age of the respondents was 45 years (interquartile range = 30-80) years. All the households had normal values of cadmium in the food analyzed. The majority of households (97.8%) had elevated mercury levels in analyzed food. Approximately 4.2% of households had increased lead levels. Elevated mercury levels were significantly higher in households that did not cultivate the food they consumed (median = 2.503 mg/kg, P = .05), those that did not use fertilizer on their farms (median = 2.522 mg/kg, P = .02), and those whose farms were located outside their communities (median = 2.733 mg/kg, P = .020). Households that did not use fertilizer on the farm (median = 0.027 mg/kg, P = .007), and those that primarily consumed rice (median = 0.023 mg/kg, P = .005) had significantly higher lead concentrations.

Conclusions: We identified high levels of mercury in food samples of the majority of the households studied. Elevated levels of mercury were associated with food cultivation practices and fertilizer use. We recommend future studies that will identify points of food contamination and inform the development of appropriate environmental remediation measures.