Health risk indices associated with heavy metals from vegetables cultivated in Tsagero District, Rimi Local Government Area, Katsina State, Nigeria

Abstract

Local preservation of vegetables involves drying to enhance shelf life. The drying processes could, in turn, contaminate the vegetables with environmental heavy metals. Ingestion of foods contaminated with heavy metals may lead to an increase in the chances of incurring cancer and other health disorders in the consumer population. This study investigated heavy metals contaminations and health risks associated with the consumption vegetables from Turaji, Tsagero District, Rimi Local Government Katsina State, North west Nigeria. The vegetables were three samples of Solanum lycopersicum L. (tomato) as fresh tomato, tomatoes sun-dried along tarred road side, and tomatoes air-dried on farmland soil; three samples of Capsicum annuum (sweet pepper) as fresh sweet pepper, sweet pepper sun-dried along tarred road side and sweet pepper air-dried on farmland soil. The samples were grinded, ashed and digested with HNO3 and HCl separately using standard methods. The heavy metals (Cu, Ni, Fe, Cr, Cd, Mn, Zn, and Pb) contents of the samples were analyzed using atomic absorption spectrophotometry. Daily intake, non-carcinogenic and carcinogenic risks as well as hazard indices of the heavy metals were determined. Results of the study showed that the vegetables analyzed generally have low levels of the heavy metals, with Ni being below detection level (BDL) in all the samples. All of the detected heavy metals concentrations were below the maximum permissible limits as set by the regulatory agencies. The calculated target hazard quotient (THQ) Health risk indices (HRIs) of the evaluated heavy metals in all the samples were therefore, less than 1. The Incremental Life time Cancer Risk (ILCR) to the population from consumption of the samples lies within the safe limit (≤10-4). From the results, these vegetables are hence, safe for human consumption.