Assessment of selected heavy metals pollution (chromium, lead, and cadmium) in edible vegetables and agricultural soils influenced by tannery activities in the Amhara Region, Ethiopia.

Abstract

Industrial heavy metal pollution in agricultural soils threatens food safety and human health. This study assessed chromium (Cr), lead (Pb), and cadmium (Cd) concentrations in soils and vegetables collected from four tannery sites in Ethiopia's Amhara region. Soil and vegetable samples were subjected to wet digestion, and metal concentrations were determined using flame atomic absorption spectrometry (FAAS). Results showed soil samples contained Cd concentrations ranging from 7.41 to 15.1 mg/kg, Pb from 14.3 to 23.0 mg/kg, and Cr from 77.3 to 257.1 mg/kg. Variation was observed among vegetable samples. Lead concentrations reached 2.6 mg/kg in cabbage from Kombolcha and 6.1 mg/kg in potatoes from Bahir Dar and Habesha. Cadmium levels ranged from 0.4 mg/kg in lettuce to 1.9 mg/kg in tomatoes from Kombolcha, while chromium concentrations reached 14.4 mg/kg in Kombolcha tomatoes and 24.3 mg/kg in potatoes from Bahir Dar and Habesha. Heavy metal concentrations in vegetable samples exceeded FAO/WHO permissible limits. Most soil samples exceeded the permissible limits for the investigated heavy metals, including Cd, while Cr concentrations in Kombolcha soil remained below the referenced guideline value. These findings emphasize the need for monitoring and pollution control measures around tannery effluent-affected areas to protect ecosystems and human health.