Significant reduction of blood and tissue lead and cadmium concentrations in free-range and broiler chickens through soil remediation with biochar, phosphates, and calcined dolomite: Implications for public health and food safety

Food safety is increasingly threatened by environmental metal contaminants such as lead (Pb) and cadmium (Cd), which accumulate in animals, including poultry and poultry products. Consumption of these contaminated products could pose a health risk to humans, which could manifest itself in the form of neurological, renal, or developmental disorders. This concern is particularly critical in mining-affected regions such as Kabwe in Zambia. The current study evaluated the efficacy of four soil amendments: biochar (BC), triple superphosphate (TSP), phosphoric acid (PA), and calcined dolomite (CD) in reducing toxic metal accumulation in chicken tissues raised on Pb and Cd-contaminated soils. Using ex-situ and in-vivo approaches, chickens were raised on both amended and non-amended soils, and chicken organ samples were analyzed using inductively coupled plasma mass spectrometry. Biochar was the most effective amendment, significantly reducing (p < 0.05) both Pb (by 73.6 to 90.3 % and 63.2 to 89.8 % in free-range and broiler chickens, respectively) and Cd (by 56.8 to 89.7 % and 50.2 to 77.5 %) accumulation in various organs compared to the positive control (PC) group. Importantly, the levels of essential trace elements such as copper and zinc remained stable across treatments, maintaining the nutritional quality of poultry meat. These findings highlight the potential of cost-effective and accessible soil amendments, particularly BC, in reducing heavy metal transfer from contaminated soils to poultry. This approach has the potential to enhanced food safety and protect public health in regions burdened by metal contamination. However, further long-term and field-scale studies are needed to establish the effectiveness and sustainability of soil amendment use.