INVESTIGATION OF HEAVY METAL POLLUTION AND HEALTH RISKS DUE TO FARMING ACTIVITIES ON A FORMER DUMPSITE IN DAR ES SALAAM, TANZANIA
The heavy metal pollution from a former solid waste disposal site in Dar es Salaam, Tanzania, that is currently used for urban farming was investigated. The pollution was assessed by measuring the content of copper, lead, zinc and chromium in soil, plants and leachate from the site as well as in the adjacent river. The safe daily intake of onsite cultivated vegetables, in regard to the heavy metal content, was calculated. The analysis showed that there is a health risk connected to consuming vegetables in volumes greater than 100 g cowpea leaves, 70 g pumpkin leaves or 1700 g maize grains for someone with a body weight of 80 kg due to the concentration of Pb. The heavy metal content in leachate exceeded the Swedish limits for leachate discharge to water recipient. The river water contained too high levels of Cr to be within the FAO standards set for irrigation water. Measures are urgently needed to cover the site with a final layer and collecting the leachate for purification. To stop further contamination from the Vingunguti dumpsite the bottom and sides of the dump need to be covered to ensure a fully enclosed site. The local community also needs to be informed of the risks connected to urban farming in the area.
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