Estimation of Heavy Metals in Neem Tree Leaves along Katsina – Dutsinma – Funtua Highway in Katsina State of Nigeria

Widespread and growing use of medicinal plants has created public health challenges in terms of quality, safety and effectiveness. Using Atomic Absorption Spectrophotometer (AAS), concentrations of Ni, Zn, Mn, Cu, Cr and Pb, , were determined in samples of neem tree (Azadirachta indica) leaves obtained from Katsina, Dutsinma, Kankara and Funtua along Katsina – Dutsinma – Funtua highway in Katsina state of Nigeria. The mean level of the metals in the various locations along the highway varied between Ni (1.14mg/Kg and 1.92mg/Kg); Zn (2.48mg/Kg and 6.08mg/Kg);Mn (2.67mg/Kg and 4.72mg/Kg); Cu (1.91mg/Kg and 2.99mg/Kg); Cr (0.17mg/Kg and 0.37mg/Kg) and Pb (0.77mg/Kg and 2.25mg/Kg). Samples from Katsina indicated the highest levels of Zn, Ni and Pb while samples from Funtua indicated the highest levels of Cu and Cr. However, the levels of all metals obtained from the samples from various locations along the highway were below the WHO/FDA permissible levels of heavy metals in herbal plants.