Assessment of Heavy Metals in Tomatoes, Green Beans and some Vegetables on Road Side Farms in Farin-Lamba, Jos South Local Government Area Plateau State, Nigeria

Abstract

Heavy metals retention by vegetables and crops planted along road-side is of awesome concern due to dangers associated with human health risks. This paper therefore evaluates the levels of heavy metals in onion bulbs, onion leaves, tomato fruit, cabbage, carrot roots, green beans and green pepper on Road-side Farms in Farin-Lamba, Jos South Local Government Area, Plateau State, Nigeria using AAS model AA240FS. The results of analysis show that the mean concentration of the heavy metals obtained by sum of all the plants analyzed were Cd: 0.633 ±.02; Cu: 0.209 ± 0.07; Pb: 0.756 ± 0.5; Cr: 0.566 ±0.07; Mn: 0.457 ± 0.3; Zn: 0.663 ± 0.1 and Ni: 0.057± 0.02, respectively. The result shows that the vegetable samples have high content of lead and low content of nickel. The average values of the heavy metal content obtained were compared to Food and Agricultural Organization (FAO) and world Health Organization (WHO) Standard limits, cadmium 0.2 mg/kg, copper 0.1 mg/kg, lead 0.3 mg/kg, chromium 2.3 mg/kg, manganese 0.4 mg/kg, zinc 3.3 mg/kg and nickel 5.0 mg/kg. The results from the study show that the mean concentration of chromium, zinc and nickel were within the permissible limits set by FAO/WHO with exception of cadmium, copper, lead and manganese which were higher than the permissible limits. Therefore, consumption of these vegetables by members of the communities where these vegetables were planted or other communities expose the population to adverse effects of these heavy metals. This may pose a serious health challenge on long term consumption of the vegetables.