Investigating the Concentration of NO3- and Heavy Metals in Some Leafy Vegetables in the Greenhouses of Kermanshah County

Background: Vegetables are an important part of healthy diet. This study investigated the concentration of heavy metals and nitrate (NO3-) in leafy vegetables cultivated within selected greenhouses in Kermanshah County. Methods: The concentration nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), iron (Fe), and cadmium (Cd) were determined using an atomic absorption spectrometer. NO3- content was measured utilizing a spectrophotometer at a wavelength of 410 nm. To assess the potential health risks associated with vegetable consumption, the health risk index (HRI) for non-cancerous diseases was employed. Results: A significant difference was evident among the three examined vegetables regarding their concentrations of heavy elements and NO3-. Spinach exhibited the highest NO3- content at 203.33 mg/kg, while mint demonstrated the lowest at 113 mg/kg. Among the studied vegetables, spinach exhibited the highest concentrations of NO3- (203.33 mg/kg) and Fe (177.66 mg/kg). Coriander showed the highest concentration of Cd (0.366 mg/kg) and Ni (1.900 mg/kg), while mint displayed the highest concentration of Cu (40.0 mg/kg). The concentration of Ni, Pb and Cd in all three studied vegetables was higher than the World Health Organization (WHO) limit. The HRI for non-cancerous diseases was less than one for the studied heavy metals, and it was higher than one for NO3- in spinach (1.080). Conclusion: Given that prolonged consumption of vegetables poses a risk of carcinogenesis to consumers, it is imperative to implement corrective measures and maintain ongoing monitoring of heavy metal and NO3- levels in crops cultivated within greenhouses in Kermanshah.