Investigation of Heavy Metal Levels in Talinum Fruticosum (Waterleaf) Cultivated on Dumpsites in Ogwashi-Uku, Delta State, Nigeria

The contamination of leafy vegetables with heavy metals from dumpsite soils constitutes a growing public health concern in Nigeria. This study assessed the concentrations of cadmium (Cd), lead (Pb), chromium (Cr), and mercury (Hg) in Talinum fruticosum (waterleaf) harvested from four dumpsite locations in Ogwashi-Uku, Delta State. Leaf samples were collected, authenticated, dried, pulverized, and digested using an aqua regia–perchloric acid mixture. Metal concentrations were determined by atomic absorption spectrophotometry. Results (mean values, mg/L) were as follows: Cd ranged from 0.030 to 0.083; Pb from 0.063 to 0.216; Cr from 0.044 to 1.042; and Hg from 0.014 to 0.449. All Cd, Pb, and Cr values were below the respective FAO/WHO soil guideline values of 1.0, 50, and 150 mg/L. However, Hg exceeded the guideline value of 0.3 mg/L at Ogbe-Onitsha (0.449 mg/L), indicating localized contamination. The findings suggest that while the vegetables are largely safe with respect to Cd, Pb, and Cr, the elevated Hg level at one site warrants precautionary measures. Routine monitoring of heavy metals in vegetables cultivated on or near dumpsites is recommended to safeguard consumer health.