NICKEL, CADMIUM, MERCURY AND OXIDATIVE STRESS STATUS OF BITTER LEAF (Vernonia amygdalina) FROM USELU AND IKPOBA HILL MARKET IN BENIN CITY

ABSTRACT

Bitter leaf are common vegetable taken by populations in Nigeria, as a vegetable, it is a rich source of essential nutrients, and antioxidants. However, both essential and toxic elements are absorbed by vegetables from the soil by the apoplast of plant roots and further distributed and accumulated into their edible and non-edible parts, posing an imminent danger to the food chain. The aim of this study is to access the level of nickel (Ni) cadmium (Cd), and mercury (Hg) contamination in bitter leaf (Vernonia amygdalina) across Ikpoba Hill and Uselu market in Edo State Nigeria. From the result of the experiment, the mean concentrations of Nickel were notably high in the bitter samples from both areas 0.0779 and 0.0957 for Ikpoba Hill market Uselu Market respectively. Cadmium levels ranged from 0.0079 mg/g in Ikpoba Hill market to 0.0071 mg/g in Uselu market, while mercury was not detected in bitter leaf samples from both locations. The variations in metal contents could have been as a result of soil properties, metal absorption capacity by plants, and various environmental and human factors. The cadmium levels in bitter leaf samples exceeded the permissible limit set by FAO/WHO, while nickel levels were within acceptable levels for human consumption. Mercury was absent in the samples The findings underscore the potential of antioxidant enzymes, particularly catalase (CAT, SOD, GPX) and Malondialdehyde (MDA) as biomarkers for heavy metal pollution in bitter leaf samples collected from Ikpoba Hill Market and Uselu Market.. The Hazard Quotient for Nickel and Cadmium was below 1 in both markets, indicating a lower risk of adverse health effects from individual metal exposure. The Hazard Index for both markets is below 1, indicating that the combined intake of Nickel and Cadmium does not pose a significant health risk from these metals through the consumption of bitter leaf. However, it's essential to consider other potential sources of exposure and cumulative health risks from multiple contaminants.