COWS AND GOATS AS SENTINELS FOR ENVIRONMENTAL LEAD (Pb) BURDEN IN ZARIA, NIGERIA

Blood lead levels (BLLs) is considered as a good indicator of current body burden of the toxic metal. Assessment of BLLs of white Fulani cattle(Bos primigenius indicus)and red Sokoto goats (Capra aegagrus hircus) grazed freely on open pastures in Zaria was carried out by Atomic Absorption Spectrophotometry using Shimadzu Atomic Absorption Spectrophotometer (model AA-6800, Japan) after wet digestion to evaluate the potential effects of the metal on the animals, the toxicological implication of consuming this major source of animal protein by humans and most importantly as an indirect measure of the lead pollution status of Zaria ecological geochemical environment. The blood lead levels of Bos primigenius indicus ranged from a minimum of 0.62 mg/l to a maximum of 2.28 mg/l with a mean value of 1.36±0.48 mg/l. On the other hand, blood lead levels of Capra aegagrus hircus ranged between 0.26 mg/l and 1.56 mg/l with a mean value of 0.89±0.43mg/l. The BLLs of both cows and goats were found to exceed the allowable limit for the elements in blood of food animals indicating that cows and goats grazed freely on open pastures in Zaria metropolis are not safe for human consumption. Routine monitoring of the heavy metal in plant and animal products is therefore recommended to safeguard human health. Most importantly, the study indicates the presence of elevated levels of environmental lead in Zaria ecological geochemical environment.