Assessment of heavy metal contamination in vegetables collected from selected localities of Okara, Pakistan

Saba Younas, Syeda Anjum Tahira, Umer Farooq


Background: Human health is prone to heavy metals especially which become part of food chain by any means. Previously, no extensive nutritional studies are conducted on local food products and grains. The research work was carried out to observe level of heavy metals in vegetables sold or consumed in different localities of Okara city, Pakistan.

Methods: The concentration of heavy metals Nickel, Cadmium, Cobalt, Copper and Chromium in ten different types of vegetables collected from selected sites survey were analyzed using tri-acid method for atomic absorption spectrometer.

Results: The results showed that concentrations of all analyzed heavy metals were significantly (P≤ 0.05) different, except values of copper in collected vegetable samples. The average concentration ranged from 5.4 – 44.06 ppm of Cobalt, 5.7 – 9.63 ppm of Copper, 4.49 – 11.13 ppm of Cadmium, 4.59 – 33.77 ppm of Chromium and 8.58 – 13.68 ppm of Nickel. Mean concentrations of metals were found in following sequence Copper < Cadmium < Nickel < Chromium < Cobalt.

Conclusion: It was concluded that vegetables can accumulate high concentrations of Cobalt and Chromium while Nickel,  Cadmium and Copper concentrates in low amount,  from which level of chromium and cadmium surpasses the permissible limits by FAO/WHO especially in underground vegetables (Onion and Radish), which could be the cause of serious health issues. Hence, monitoring and assessment of contaminants in vegetables are periodically needed and public safety measures should be imposed.

Keywords: Heavy metal; Bio-concentration; Vegetables; Pakistan

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