Heavy Metals Health Risk Assessment through Consumption of Baobab Leaf Cultivated in Katsina State, North West Nigeria

Abstract

Vegetables play important roles in human nutrition and health. They can also contain some undesirable components that can be harmful, e.g.  Pesticides and heavy metals. The objectives of the study were mainly to detect the presence of heavy metals (Cr, Cd, Fe, Ni, Mn, Pb and Zn) in sampled Baobab leaf in Katsina state Nigeria and assessed the human health risks associated with the consumption of the Baobab leaves. The content of these metals was assayed by the AAS method. The health risk to the local inhabitants was evaluated by estimating daily heavy metal intake and computing the Incremental Lifetime Cancer Risk (ILCR) and the Target Hazard Quotient (THQ) for cancer and non-cancer risks. The results were compared with the safety standards established by the WHO/FAO and USEPA. With the exception of the heavy metal Pb (0.526-0.981) the mean concentration (mg/kg) range values of Cr (0.116-0.352), Cd (0.041-0.054), Fe (1.016-1.951) and Zn (0.940-1.229) in the samples were generally lower than the USEPA, WHO/FAO maximum permissive limits. The risk level of Target Hazard Quotient (THQ < 1) was observed for all the evaluated heavy metals for both adults and children. The THQ for the samples was in the decreasing order Zn>Fe>Pb>Cr>Cd, for all the baobab leaf samples respectively. All the studied samples showed the risk level (HI < 1). ILCR for Cd violated the threshold risk limit (>10−4) and ILCR for Pb reached the moderate risk limit (>10−3) for cancer in all the studied samples in adults, While in children ILCR for Pb in samples from Dabai and Daura have reached the moderate risk limit (>10−3), while the ILCR for Pb in rest of the samples and ILCR for Cd of all the samples are beyond the moderate risk level (>10−2). The consumption of the Baobab leaf sample may contribute to the population cancer burden.