Assessment of heavy metal concentrations in food crops from Pece wet land in Gulu Township, Northern Uganda

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Kampala International University, School of Engineering Science
The present study is aimed at assessing the concentrations of heavy metals in food crops from pece wet land Gulu town ship. The study investigated heavy metals which include Copper, Zinc, Lead, and Cadmium in the soil and in selected crops which were banana fruit, sugar cane, coco yam and green vegetables (Amaranthus dubius). Metals are essential for maintaining human health throughout life however, at high concentrations they become poisonous. In Gulu town ship, waste disposal and management is still a challenge, wastes are dumped anywhere and when it rains they are taken by runoffs into pece wet land which is also used as a dumping site and on the other hand utilized for agriculture. Intake of heavy metal contaminated crops may pose a risk to the human health. Plants take in minerals from soil media or air through their roots or foliage. Understanding the distribution of some trace metals in some common food crops is important for establishing baseline concentrations from which anthropogenic effects can be measured. This will provide a basis for encouraging people to undertake proper care in the handling and disposal of solid wastes in addition to providing analytical data for further research. Soil and plant samples were collected from Pece wet land Gulu Township which was used as a dumping site and other samples from Katikamwe wet land in Bushenyi district which served as a control site. The samples from both sites were transported to the laboratory well prepared, soil parameters pH and electrical conductivity determined using a pH meter and a conductivity meter bridge respectively Samples were digested using acids and the concentrations of heavy metals Cadmium, Copper, Lead and Zinc determined using Atomic Absorption Spectrophotometer. The results showed that the soils in municipal waste dump sites are higher in heavy metals: Cd (1.35 ± 0.44)mg/kg, Cu (36.23 ± 4.04)mg/kg, Pb (46.23 ± 1.68) mg/kg and Zn (151.36 ± 2.22)mg/kg compared to those of the control site Cd (0.65 ± 0.0l)mg/kg, Cu (18.22 ± 3.22)mg/kg, Pb (12.56 + 3.36)mg/kg, and Zn (7.50 ± 2.76)mg/kg, suggesting possible mobility of metals from dumpsites to farmlands through leaching and runoffs. Soils from Gulu town ship had higher pH and EC values than the control site 6.35±0.07 compared to 5.47±0.09 and 167 ± 6 compared to 143 ± 3 respectively.
A thesis presented to the college of higher degrees and research Kampala International University Kampala, Uganda in partial fulfillment of the requirements for the Degree of Master of Science in Chemistry
metal concentrations, food crops, Gulu Township