Heavy Metals in Five Leafy Vegetables from Urban and Periurban Sites in Ngaoundere, Cameroon

Heavy metal concentrations were estimated in selected five leafy vegetables (Solanum nigrum, Brassica oleraceae, Lactuca sativa, Amaranthus hybridus and Corchorus olitorius) from urban and periurban sites in Ngaoundere (Cameroon) using an Atomic Absorption Spectrophotometer (AAS). Vegetable samples were collected at the usual stage of harvesting. The highest concentrations of Fe (673.92 mg/kg DW), Cu (10.42 mg/kg) and Pb (34.39 mg/kg DW) were recorded in Lactuca sativa, Zn(86.92 mg/kg DW) in Solanum nigrum, Cd (0.93 mg/kg DW) in B. oleracea and Ni (16.91 mg/kg DW) in Corchorus olitorius. Some of the concentrations of Ni and Pb in vegetables exceeded the critical level for plant growth. The transportation index (Ti) indicated that Cu and Pb were more accumulated in roots than in aerial parts of leafy vegetables. Vegetables were more contaminated in urban site than in periurban site. In all farms, the lead concentrations in all vegetables exceeded the FAO/ WHO maximum recommended level in leafy vegetable for human consumption, while all vegetables from only urban sites had some Cd concentrations that were higher than limits set by FAO/WHO. So, the vegetables produced especially in urban sites in Ngaoundere are not suitable for human consumption.