HEAVY METALS IN VEGETABLES GROWN IN KORANGI AREA, KARACHI, PAKISTAN

Abstract

Karachi is the most congested city of Pakistan where a big part of vegetables is irrigated by waste water of two main rivers i.e. Malir and Lyari Rivers. This study was conducted to see the presence of heavy metals in samples of vegetables cultivated by waste water of Malir River. This contained mainly sewerage water and very small portion of industrial effluent. The levels of the six different heavy metals i.e. cadmium (Cd), lead (Pb), cobalt (Co), iron (Fe), manganese (Mn), zinc (Zn) were determined in various vegetables. Turnip (Brassica Rapa) and its leaves, radish (Raphanus sativus) and its leaves, fenugreek leaves (Trigonelle sp.) and anethumsowa (Abelmoschus moschatus) and spinach (Spinacia oleracea) were collected from Sharafi Goth in Korangi during winter season and brought to the Federal Urdu University of Arts Science & Technology Gulshan-e-Iqbal Campus for analysis. Atomic absorption spectrophotometer was used to determine the concentration of heavy metals in each vegetable. The amount of Cd, Mn, Fe, Zn in the vegetables samples were below the permissible values as per EU standards. In case of lead and cobalt, some of the vegetable contained more than permitted values. Turnip (Brassica Rapa) leaves had maximum concentration of lead i.e. 8.45ppm which was 28 times higher the allowed limit. It is concluded that since excessive accumulation of heavy metals in vegetables effect the food quality. Therefore, it is highly recommended that efforts should be made to control the irrigation of vegetables using contaminated Malir river water.