Determination of heavy metal contamination of street-vended fruits and vegetables in Lagos state, Nigeria

Fruits and vegetables are edible plant products that are good for health. Precise qualitative and quantitative analyses of heavy metals present in them are important for accurate nutritional labeling, determination of compliance with the standard of identification and in ensuring that the products meet manufacturer’s specification. Data and information about heavy metal contamination of street-vended fruits and vegetables in many parts of Nigeria are not available in the literature. Therefore, 162 samples consisting of six different fruits and leafy vegetables were purchased from two major markets in Lagos, Nigeria and analyzed for their heavy metal concentrations using Atomic Absorption Spectrometry (AAS). Cadmium (Cd), zinc (Zn), copper (Cu), cobalt (Co) and nickel (Ni) were found in the samples of the three types of fruits (mango, pawpaw and watermelon) and three types of leafy vegetables ( smooth amaranth, cabbage and lettuce) studied; but chromium (Cr), arsenic (Ar) and mercury (Hg) were not detected in all. Manganese (Mn) and Lead (Pb) were also absent in mango and smooth amaranth respectively. The results further indicated that the fruits and vegetables collected from the chosen markets have heavy metal concentration within the safe limits prescribed by WHO/FAO except for Pb. The study will bring awareness to consumers of these items about what they are taking and the health implication as well as assist them and the farmers in taking necessary precautions towards proper care of their fruits and vegetables before consumption. This will indeed be a good way of reducing substantial quantity of contaminants from getting to the human body thereby avoiding health problems, with its attendant positive economic implication.