EVALUATION OF HEAVY METALS CONTAMINATION AND ASSOCIATED HEALTH RISKS IN PASTEURIZED AND UNPASTEURIZED COW MILK IN GASHUA, YOBE STATE, NIGERIA

Abstract

Milk is a vital source of nutrients but may also serve as a pathway for toxic heavy metal exposure. This study assessed cadmium, chromium, lead, and mercury in cow milk consumed in Gashua, Yobe State, Nigeria. To determine the levels of Cd, Cr, Pb, and Hg in pasteurized and unpasteurized cow milk, compare the findings with WHO limits, and evaluate associated health risks. A cross-sectional study was conducted using 10 milk samples (5 pasteurized, 5 unpasteurized) collected from sales points through a stratified random sampling technique. Atomic absorption spectrophotometry was used to determine heavy metal concentrations. Health risk assessment was performed using estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and incremental lifetime cancer risk (ILCR) based on United States Environmental Protection Agency (USEPA) standards. Data were analyzed using descriptive statistics. Mean concentrations of Cd (0.012–0.017 mg/L), Cr (0.153 mg/L), and Pb (0.220–0.228 mg/L) exceeded WHO permissible limits, while Hg (0.0026–0.003 mg/L) remained within safe levels. Health risk assessment showed that EDI, THQ, and HI values were <1, indicating no immediate non-carcinogenic risks. However, ILCR values approached the upper acceptable limit, particularly in children. Pasteurized and unpasteurized cow milk in Gashua, Yobe State, is contaminated with Cd, Cr, and Pb above safe limits. Although immediate non-carcinogenic risks appear low, the potential long-term carcinogenic risks, especially in children, warrant routine monitoring and preventive interventions. Strengthen regulatory frameworks and establish routine monitoring systems to ensure milk safety and protect public health is suggested.