Estimation of Some Heavy Metal Levels in Fresh Cut Vegetables Vended in Adamawa State, Nigeria

This study was conducted to estimate the levels of Cd, Pb, Cr, Zn, Ni, Fe and Cu present in fresh-cut leafy vegetables vended in Adamawa State. Three local government areas were purposively selected out of the three senatorial zones that made up the State, and one major horticultural market was also purposively selected from each of the selected zones. Three samples of fresh-cut lettuce and cabbage salads were collected from three different vendors in each zone, which were subjected to heavy metal contaminant analyses using AAS method at the Nutrition Laboratory of Adamawa State University, Mubi. Data collected were analyzed using Analysis of Variance (ANOVA) using IBM SPSS Statistics version 23 software, and means were separated using Duncan Multiple Range Test (DMRT) at a 5% level of significance. A very high significant (P ≤ 0.001) differences occurred in the concentration of Cd, Pb, Cr and Zn in fresh-cut cabbage salads while in case of fresh-cut lettuce salads, a very high significant (P ≤ 0.001) difference in the concentration of Cd, Pb, Cr, Zn, Ni, Fe and Cu in fresh-cut lettuce salads in the State. Fresh-cut cabbage salads produced in Yola zone had the highest levels of Cd = 0.354, Pb = 0.243, and Cr = 0.424 mgKg-1, while the highest value of Zn = 7.643 mgKg-1 was recorded in Numan zone. Similarly, Fresh-cut lettuce salads produced in the Yola zone had the highest level of Cd = 0.2900, Pb = 0.2433, Cr = 0.3222, Ni = 0.4322 and Fe = 15.48 mgKg-1, while Mubi zone recorded the highest value of Cu = 0.8211 and Numan had highest level of Zn = 7.6467 mgKg-1. Fortunately, all the values for the seven heavy metals studied are below the maximum permissible limit set by FAO/WHO (Cd = 0.2, Pb = 0.3, Cr = 2.00, Zn = 99.4, Ni = 67.9, Fe = 425.5 and Cu = 73.3 mgKg-1) except Yola that recorded dangerous levels of Pb above the safety levels in both products. Additionally, the levels of heavy metals observed in this study are the lowest when compared with the values recorded in other parts of the country; as such, the fresh-cut vegetable salads vended in Adamawa State are safe for consumption in terms of heavy metal content.