Assessing heavy metal contamination in leafy vegetables and associated health risks in Dhaka, Bangladesh

Abstract Leafy vegetables, widely consumed for their nutritional benefits, can pose significant health risks when contaminated with toxic metals, emphasizing the need to monitor and assess their safety. An atomic absorption spectrophotometer (AAS) was used to analyze the metal accumulation in leafy vegetables. The specific minerals analyzed included calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn), and iron (Fe). Additionally, heavy metals such as copper (Cu), cadmium (Cd), lead (Pb), chromium (Cr), cobalt (Co), and nickel (Ni) were also examined. Risk factors for the human population were examined, focusing on the transfer of metals from different sources to vegetable samples. These metals were then consumed by humans through the ingestion of leafy vegetables that had accumulated them. The results of this study showed that the average concentrations detected ranged from 68.0 to 1507 mg/kg of Ca, 126.0 to 829.0 mg/kg of Mg, 4.03 to 44.0 mg/kg of Zn, 2.7 to 74.5 mg/kg of Mn, 25.0 to 154.5 mg/kg of Fe, 0.74 to 4.51 mg/kg of Cu, 0.005 to 0.22 mg/kg of Cd, 0.19 to 1.75 mg/kg of Pb, 0.43 to 4.69 mg/kg of Cr, 0.005 to 0.39 mg/kg and 0.25 to 2.21 mg/kg of Ni. The highest mean levels of minerals like Ca, Mg, Zn, Mn and Fe were detected in red amaranth, Garden purslane, Stem amaranth. The study used, estimated daily intakes (EDIs), target hazard quotient (THQ), and cancer risk (CR) assessments to assess the potential health risks of consuming contaminated vegetables. The results showed that the value of THQ was found to be larger than 1 in the cases of Pb and Mn in Stem Amaranth, indicating a significant non-carcinogenic health risk, especially due to high lead exposure exceeding the standard limit by two-fold in all fields. Furthermore, the CR values for Cd, Cr, and Ni indicated a notable carcinogenic risk in multiple cases.