Abstract:
This study was carried out to assess the concentration
levels of heavy metals in vegetables grown on urban waste dumpsites. The
research was carried out on three waste dumpsites in Kumasi where vegetables
cultivation (cabbage, lettuce and spring onions) are practised. Experimental
plots of cabbage, lettuce and spring onions were set up at these sites
and harvested at complete maturity stage. Crops and soil samples were
collected and analysed for the presence of four heavy metals: cadmium,
lead, copper and zinc. Cadmium levels recorded were in the range of 0.68-1.78
mg kg-1 as against WHO/FAO recommended level of 0.20 mg kg-1;
lead had values in the range of 2.42-13.50 mg kg-1 as against
the WHO/FAO recommended guideline value of 0.30 mg kg-1; copper
levels were in the range of 16.17-90.33 mg kg-1 as against
the WHO/FAO recommended guideline value of 73.3 mg kg-1 and
zinc had values between 26.77-106.83 mg kg-1 compared to the
WHO/FAO recommended guideline value of 99.40 mg kg-1. The levels
of the two most toxic heavy metals, cadmium and lead, were far higher
in the vegetables than the WHO/FAO recommended values and the transfer
factors of these two metals were also the highest suggesting that consumption
of vegetables grown on such sites could be dangerous to human health.
Samuel Nii Odai, Ebenezer Mensah, Dela Sipitey, Shoji Ryo and Esi Awuah, 2008. Heavy Metals Uptake by Vegetables Cultivated on Urban Waste Dumpsites: Case Study of Kumasi, Ghana. Research Journal of Environmental Toxicology, 2: 92-99.
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