Heavy Metal Contamination in Green Leafy Vegetables Collected from Selected Market Sites of Piliyandala Area, Colombo District, Sri Lanka

Abstract

The content of nickel (Ni), cadmium (Cd), chromium (Cr), lead (Pb) and copper (Cu) in five different types of green leafy vegetables viz., Kangkung (Ipomoea aquatica), Mukunuwenna (Alternanthera sessilis), Thampala (Amaranthus viridis), Nivithi (Basella alba) and Kohila (Lasia spinosa) collected from four randomly selected urban and sub urban market sites in and around Piliyandala area of Colombo District, Sri Lanka, were measured using atomic absorption spectrometry. The results showed significant differences in elemental concentrations among the green leafy vegetables analyzed. The average concentrations of heavy metals detected in green leafy vegetables ranged from 0.71-15.89, 0.07-0.97, 0.18-5.05, 0.18-1.59, 7.05-18.44 mg/kg for Ni, Cd, Cr, Pb and Cu respectively, on dry matter basis. In addition, the mean concentrations of metals in the green leafy vegetables were found in the order of their abundance as Cu>Ni>Cr>Pb>Cd. However, there were no significant differences (p < 0.05) between the heavy metal contents in combined green leafy vegetables collected from the four market sites. It was also found that the Ni, Cd, Cr and Pb levels exceeded the maximum permissible limits set by FAO/WHO for human consumption.