Bio-Concentration Factors of Heavy Metals in the Leaf and Root System of Some Selected Vegetables along the Dilimi River in Jos North, Plateau State, Nigeria

Abstract

This research sought to evaluate the bio-concentration factors of specific heavy metals to facilitate the sustainable management and use of irrigation sites. Sixteen samples of lettuce and spinach were gathered, and each was divided into leaves and roots, placed into a different polythene bag and tagged with the plant's name, part, and stratum. The heavy metals that were analyzed included Lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), iron (Fe), and Nickel (Ni). The analysis was done using Atomic Absorption Spectroscopy (AAS). The findings showed that all the metals Cr, Fe, Pb, Ni, Zn, and Cd were within the WHO recommended permissible limit in soils, despite the vegetables having higher Fe concentrations than the recommended limit of 20.00 ppm. The results also showed that the roots and leaves of spinach and lettuce vegetables primarily categorized the heavy metals as having moderate Bio-Concentration Factor (BCF) values, which ranged between 0.1 and 1.0. The results also revealed hyper-accumulation of Ni (1.723) and Cr (1.249) in the leaves of lettuce and spinach. The results also indicate a weak relationship between plants and the heavy metals in the soil. The strongest association (r = -0.512) was found between Ni in the soil and Fe in the vegetables. Farmers along the river should be made aware of the detrimental consequences of their actions.