An investigation of toxic heavy metals (Pb, Cd, Cu, Cr and Zn) in Garlic (Allium sativum L.) and soil samples collected from different locations of Punjab, Pakistan using atomic absorption spectrometry

Abstract

The present study is based on the determination of heavy metal contents (Pb, Cd, Cu, Cr and Zn) in garlic and soil samples collected from ten different locations of Punjab, Pakistan using flame atomic absorption spectrometer. In garlic samples, Pb, Cd, Zn, Cu and Cr ranged from 4.9 to 94.6 mg/kg, 0.625 to 151.4 mg/kg, 3.7 to 56.4 mg/kg, 2.5 to 50.2mg/kg and 56.4 to 111.6 mg/kg respectively, whereas Pb, Cd, Cr, Zn and Cu in investigated soil samples ranged respectively from 57.4 to 99.6 mg/kg, 25.6 to 132.7 mg/kg, 61.7 to 115.1 mg/kg, 9.2 to 324.7 mg/kg and 15.5 to 34.5 mg/kg. Elevated concentration of Pb and Cd was found in garlic samples from Gujranwala, Cr concentration was found to be higher in samples collected from Raiwind while the other metals such as Cu and Zn were predominant in samples from Kasur. Heavy metal content in soil and garlic samples was within the permissible limits proposed by World Health Organization (WHO) except Cd, Cr and Zn which showed elevated levels in almost all soil and garlic samples. Average concentrations determined in all samples represented that metal content in soil samples was in increasing order as Zn<Cu<Pb<Cd<Cr while in garlic samples, this order was as Cu<Cd<Zn<Pb<Cr. In the present study, it was observed that garlic samples from those areas presented relatively higher levels for investigated metals from where the soil samples also showed comparatively elevated levels of these metals.