Medicinal plants treatment is independent of any age groups and sexes and is used all over the world for the treatment of ailments. Accumulation of major chemical carcinogens (MCCs): Cd and Cr consumed from the leaves of Adansonia digitata, Psidium guajava and Carica papaya as therapeutic herbs leads to various health hazards. In Borno, Jigawa, and Kano States in the northern part of Nigeria with a population of 17,933,394 inhabitants, consumed these leaf extracts for the treatment of many ailments including cancers. In order to investigate the health risk impact of consuming these leaf extract, this study has been designed to evaluate the average concentration of the MCCs. This was performed using the various techniques of the High-Resolution Continuum Source Atomic Absorption Spectrometry (HRCS AAS). The results were used to estimate the daily intake of the two MCCs and the target hazard quotient (THQ). This was done to evaluate the risk associated from the regular consumption of these leaf extracts over duration of a person’s lifetime. The mean maximum concentration of the MCCs of the three herbs obtained from Borno, Kano and Jigawa States falls within the safe limits of 0.02 mg/kg (UNSCEAR 2000). The Target Hazard Quotient (THQ) for Cd was greater than one in Adansonia digitata, and Carica papaya except P. guajava from Borno state. The excess lifetime cancer risks due to the MCCs were below the threshold values of < 10-4 (EPA 2001). The MCCs evaluated in this study posed no serious health hazard to the population. The analytical method adopted in this study provides highest recovery for all the analytes under investigation using the HRCS AAS in herbal medicine samples.
Keywords: Herbs; Leaf Extracts; Target Hazard Quotient; Excess Lifetime Cancer Risk; Health Risk Assessment.