Abstract:

Heavy metal environmental contamination consequent of anthropogenic factors has become a global concern with cadmium and lead constituting a major public health, livestock and ecological threat. This study, therefore, uses goats (as sentinel animals) raised in 2 different regions based on their mining history (previous and existing) to evaluate exposure to cadmium and lead and their consequent toxicities and pathological changes. A total of 130 goats (composed of 88 goats which constitute the suspected exposure (SE) group and 44 goats, the suspected unexposed (SU) group) were sampled. Blood and tissue samples (liver, kidney and muscles) were analysed for lead and cadmium levels using Atomic Absorption Spectrophotometer along with the complete blood count analysis. The mean blood lead levels (BLLs) and cadmium levels (BCLs) in the goats from the SE groups were 14.59 and 3.12 µg/dl respectively, which were significantly higher than the SU groups (9.23 and 0.46 µg/dl respectively) A significantly higher frequency of goats in the SE (93.18%) also had an elevated BLLs compared to the SU group (78.57%). The levels of tissue lead and cadmium in both the SE and SU groups were found significant and higher than the FAO/WHO maximum limits. The packed cell volume, red blood cell count, and haemoglobin concentration were found significantly lower, and the platelet count and some leucocyte parameters (total white blood cell, neutrophil, eosinophil, and monocyte count) were found significantly higher in the SE group. The elevated cadmium and lead level in both groups further highlight the ubiquitous spread of cadmium and lead environmental contamination in both study regions and the direct risk of exposure to human and animals in Nigeria. The relative differences in the observed pathological changes in the two study groups also suggest the influence of the environmental heavy metal pollution and exposure levels on health.

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