Heavy Metal Content in some Commonly Consumed Vegetables from Kariakoo Market, Dar es Salaam, Tanzania

Abstract

This work reports on the levels of cadmium, lead, copper, manganese and zinc in 174 samples from eight varieties of green vegetables (amaranth, Chinese cabbage, cowpea leaves, green pepper, leafy cabbage, lettuce, okra and pumpkin leaf) commonly grown in Dar es Salaam and marketed at Kariakoo, Tanzania. The amount of cadmium and lead ranged between 3-42 and 11-60 μg/kg respectively. The amount of copper, manganese and zinc ranged between 0.35 - 2.12, 1.01 - 7.57, and 1.19 - 6.33 μg/kg respectively. On average consumption pattern, the contribution of these vegetables to the recommended daily intakes (RDI) for cadmium and lead ranges from 0.5 - 10.8% and 0.1 - 4.0%, respectively. The contribution of these vegetables for copper, manganese and zinc to the recommended daily intake is observed to mostly be less than 20%. The estimated dietary intakes through these vegetables show that they may be considered as an appreciable source of both heavy metals and essential trace elements due to their extensive consumption.

Keywords: Heavy metals; Vegetables; Daily intake; Kariakoo market; Food safety