Choge Phoebe*, Samuel Lutta
Department of Chemistry,University of Eldoret
P.O. Box 1125-30100 Eldoret,Kenya
chogephoebe@yahoo.com : stlutta@gmail.com

Abstract

Urban agriculture in developing countries is facing major challenges which include limited land spaces and the rising cost of artificial fertilizers. As a result, free land spaces are used to grow food crops and raw sewage sludge is applied to enhance fertility. In Eldoret town; Kenya, the old municipal dumpsite has become an ideal site for growing vegetables and sewage sludge is applied without regards to risks of toxic heavy metals and other contaminants. This research was conducted to determine levels of selected heavy metals in soil and vegetables grown in the dumpsite. A total of 42 samples were analysed using atomic absorption spectroscopy and all data were analysed using SPSS version 20.0 where significance was considered at p < 0.05. Results obtained from soil indicated the following mean concentrations: lead, 1.630 mg/Kg, cadmium, 0.070 mg/Kg, copper, 0.380 mg/Kg, zinc, 2.310 mg/Kg, iron, 101.530 mg/Kg and nickel, 10.370 mg/Kg. In kales mean concentration were as follows: lead, 1.356 mg/Kg; cadmium, 0.110 mg/Kg; copper, 0.095 mg/Kg; iron, 42.070 mg/Kg; zinc, 0.875 mg/Kg and nickel, 9.240 mg/Kg. In spinach the following concentrations were obtained: lead, 1.088 mg/Kg; cadmium, 0.090 mg/Kg; copper, 0.103 mg/Kg; iron, 22.110 mg/Kg; zinc, 0.800 mg/Kg and nickel, 9.190 mg/Kg. In onions mean concentration were as follows: lead, 0.404 mg/Kg; cadmium, 0.345 mg/Kg; copper, 0.109 mg/Kg; iron, 2.650 mg/Kg and zinc, 2.650 mg/Kg. Levels of all the heavy metals in soil were within the acceptable range of WHO/FAO while in vegetables, all the heavy metals were within the acceptable range except lead and cadmium which were above the acceptable limits. It was therefore concluded that the vegetables grown in the dumpsite are not good for human consumption due to high levels of lead and cadmium.

Keywords: Heavy metals, dumpsite wastes, wastewater, vegetables