Concentration of some heavy metals in the hair, kidney and liver of cattle and goats in the oil and non–oil producing areas of Ondo State

Abstract

Pollutions due to anthropogenic sources have made some animals possible carriers of certain toxic substances which could have detrimental effects on humans. In this study, the concentrations of lead (Pb), cadmium (Cd), mercury (Hg) and chromium (Cr) in the hair, kidney and liver of cattle and goats in the oil producing areas (OPA) and none oil producing areas (NOPA) of Ondo state, Nigeria, were evaluated. Hair, kidney and liver samples were collected from four purposely selected Local Government Areas in Ondo state in replicates, dried and digested using a 1:3 mixture of concentrated perchloric acid (HClO₄) and trioxonitrate (v) acid (HNO₃). Data collected were analyzed completely randomized design (CRD) and significant means were separated using Duncan multiple range test. Lead concentration (mg/kg) were not significantly different in the organs of cattle (mean = 0.076) and goats (mean = 0.043) in the OPA but varied significantly in the NOPA with highest values in the hair of cattle (0.081) and kidney of goat (0.056). Oil exploration effect was only significant in Pb deposition in the kidney. Cadmium values (mg/kg) ranged from 0.009 to 0.031 in cattle and from 0.010 to 0.020 in goats with no significant variation. However, oil exploration showed significant effect in the Cd deposition in the kidney of cattle. Mean values of mercury concentration (mg/kg) in cattle were between 0.022 to 0.054 and 0.029 to 0.039 in goats from the OPA. In the NOPA, Hg concentration did not vary significantly in the organs of cattle but showed significant variation in the organs of goats with values ranging from 0.016 – 0.046 mg/kg. Chromium concentration (mg/kg) varied between 0.004 to 0.020 in cattle and 0.005 to 0.025 in goats with no significant variation. Conclusively, all the heavy metal concentrations obtained from analysis of the hair, kidney and liver from both the oil producing and the non – oil producing areas were below permissible limits reported by some regulatory bodies.