Evaluating Exposure Risk of Consuming Cadmium Contaminated Spinach and Waterleaf Vegetables Grown by Roadside in Selected Areas of Kano State

Abstract

This study investigates the contamination of waterleaf and spinach, both known as Cadmium (Cd) accumulators, cultivated in open fields along roadsides exposed to vehicular emissions in five locations . Microwave Plasma-Atomic Emission Spectroscopy (MP-AES) was utilized to quantify Cd levels, revealing concentrations ranging from 0.37 to 0.94 mg/kg in spinach and 0.22 to 1.08 mg/kg in waterleaf. The research identifies Cd concentrations exceeding the FAO and WHO permissible limit of 0.2 mg/kg for leafy vegetables, rendering the consumption of spinach and waterleaf from these locations unsafe due to elevated Cd levels resulting from vehicular pollution. An exception was noted in waterleaf from , where Cd was not detected, attributed to a transfer factor. Ecological index evaluations produced contamination factor and Pollution Load Index (PLI) values of 1 and 0.01, indicating moderate contamination (1 < CF < 3) and the presence of pollution (PLI > 1). Average Daily Dose (ADD) calculations exceeded the Reference Dose limit for Cd (RfD of Cd = 0.001 mg/kg). The Estimated Daily Intake (EDI) results ranged from 0.01800 to 0.02200 mg/kg for Cd, while the Hazard Quotient (HQ) assessment based on unity classification for the analyzed vegetables showed Cd concentrations from 0.63700 to 0.01603 mg/kg. In conclusion, the computed values suggest the presence of heavy metals in the study areas, indicating an elevated risk of adverse health effects from exposure to these contaminants. The study underscores the urgent need for environmental management strategies to mitigate Cd contamination in leafy vegetables grown along roadsides.