HEAVY METAL CONTENTS AND THEIR DAILY INTAKE IN VEGETABLES UNDER PERI-URBAN FARMING SYSTEM OF MULTAN, PAKISTAN

Irrigating soil with waste water results in accumulation of heavy metals in the food chain. To examine the possible health hazards of heavy metals in local population, quantification of accumulation potential and daily intake values of heavy metals in two commonly grown vegetables of Pakistan; okra (Abelmoschus esculentus) and brinjal (Solanum melongena) was assessed. Three major sites of Multan were selected: Kot Abdul Fateh, Hamroot and Mozu Alamgir, irrigated by waste, tubewell and underground water respectively. Total 30 soil samples, 30 irrigation water samples and 60 vegetables samples were analysed. All samples of irrigation water, soil and vegetables were contaminated with heavy metals (Ni, Cd, Cu, Pb, Mn and Co). Out of contaminated, all irrigation water samples exceeded their maximum residual limits (MRLs) except Cu and Co while for soil only Cd exceeded its MRL. Documentation of accumulated heavy metals in vegetables suggests that the concentration of lead and cadmium in both vegetables is higher than their respective MRLs. However, the daily intake values of these metals in both children and adults were below their recommended values according FAO/WHO. The study suggests that regular monitoring of trace-metals may be helpful in controlling unnecessary build-up of trace metals in the food chain.