Heavy Metal Contamination in Green Leafy Vegetables Collected From Different Market Sites of Kathmandu and Their Associated Health Risks

Abstract

The present study was carried out to assess contamination of five heavy metals (As, Cd, Cr, Pb and Zn) in five different types of green leafy vegetables viz., mustard (Brassica campestris), garden crees (Lepidium sativum), fennel (Foeniculum vulgare), coriander (Coriandrum sativum), and spinach (Spinacea oleracea) collected from different market sites of Kathmandu. Atomic absorption spectrometer was used to determine the concentrations of these metals in a total of 45 test vegetables. Results showed a substantial accumulation of heavy metals in roots and leafy shoots of the vegetables. The range of various metals was 0.9-12.0, 2.7-12.5 and 16.8-158.7 mg kg-1 in roots and 3.2-19.1, 5.3- 32.9 and 23.9-223.1 mg kg-1 in leafy shoots of the test vegetables for Cd, Pb and Zn respectively. However, the levels of As and Cr were found below the detection limits. Results revealed that the average concentrations of all metals (both leafy shoots and roots together) in the vegetables were found in order of their abundance as Zn>Pb>Cd. It was also found that Pb and Cd levels exceeded the maximum permissible limits set by FAO/WHO for human consumption. Daily intake of heavy metals through consumption of the vegetables was also investigated. From the present study, we conclude that a monitoring plan and a health risk assessment are necessary to evaluate the levels of metal concentration in vegetables in order to develop the proper measures for reducing excessive build-up of these metals in the food chain.

Scientific World, Vol. 11, No. 11, July 2013, page 37-42

DOI: http://dx.doi.org/10.3126/sw.v11i11.8550