Analysis of some heavy metals in cow skin (Ponmo) sold at major markets in ado-odo/ota LGA, Ogun State, Nigeria

Abstract

Many of the food markets in Nigeria are open markets where foodstuffs are usually sold on open flat trays, wooden materials and baskets. Foods on sale in the open marketplace are at high risk of being contaminated by heavy metals. This study aimed at determining the occurrence of heavy metals in cow skin (ponmo) sold at the major markets in Ado-Odo/Ota Local Government Area of Ogun State. The wet and dried forms of ponmo were sampled from three major markets, Lusada, Atan and Ota. Thirty samples of the food items were analysed for lead (Pb), cadmium (Cd), nickel (Ni), manganese (Mn) and zinc (Zn) using the Atomic Absorption Spectroscopy (AAS). The results obtained were subjected to one-way analysis of variance (ANOVA). Most of the toxic heavy metals were detected (Ni, 25.62±1.55-70.45±2.44; Pb, 1.02±0.56-1.99±0.86) in both ponmo forms. However, Cd was detected only in the dried ponmo and in only one of the markets. These non-essential metals were detected in very high concentrations above maximum allowable limits by international regulatory agencies (USDA). Where detected, Mn (46.84±1.54-83.11±2.04) was also higher than the limits that are allowed in food in the two ponmo forms only in Ota and Atan markets. Zinc (8.86±0.81-11.70±0.96) was the only metal that was generally below the regulatory limits in the ponmo forms across the three markets. The present study shows that the cow skin on sale around the study area is not entirely free from heavy metal contamination and this may have health consequences.