Assessment of Heavy Metals in Some Vegetables Sold in Urban Open Markets of Kathmandu Valley

Abstract

Present study describes the extent of heavy metal contamination in two vegetable types viz., cabbage (Brassica oleracea var capitata) and cauliflower (Brassica oleracea var botrytis) sold in urban open markets of Kathmandu valley. A total of 18 vegetable samples collected from various market sites of the valley were analyzed for heavy metals viz., As, Cd, Cu, Hg, Pb and Zn using atomic absorption spectrophotometer (AAS). Results revealed that the metal concentrations in both the vegetables tested were found in the order as Zn>Cu>Pb>Cd. The metal levels in cabbage leaves irrespective of the market sites, ranged between 0.91–2.05 mg/kg for Cd, 14.32-28.31 mg/kg for Cu, 7.29–14.70 mg/kg for Pb and 36.33–108.09 mg/kg for Zn respectively. Similarly, the metal levels in cauliflower varied from 0.81–1.50 mg/kg for Cd, 19.29–26.77 mg/kg for Cu, 10.82–21.23 mg/kg for Pb and 62.45–73.72 mg/kg for Zn respectively. However, As and Hg were found below the detection limits in both the vegetables tested. It was also found that while the mean concentrations of Cd and Pb exceeded the maximum permissible limits for vegetables, Cu and Zn were found within the safe limits as recommended by FAO/WHO. From the present study, we conclude that a regular monitoring of heavy metals in vegetables is necessary for safe consumption as well as to prevent excessive buildup of these metals in the human food chain.

DOI: http://dx.doi.org/10.3126/njst.v15i1.12008

Nepal Journal of Science and Technology

Vol. 15, No.1 (2014) 39-44