Abstract:
The concentrations of heavy metals in municipal solid waste (MSW) reflect the amount of metals
in products and are directly related to the amount of metals transferred to disposal sites. This
study was conducted on MSW dumping sites at Selate and Kile sites in Harar City, Harari
Regional State, Ethiopia to investigate the concentrations of some heavy metals in decomposed
municipal solid waste and soil. From both dumping sites separately six decomposed waste
sampling points were selected purposively to form two (a total of 2*2 = 4) composite samples
and to investigate the concentration of heavy metals in soil at both dumping sites, three soil
sampling points were purposively selected as fresh, intermediate and old waste dumping areas.
Soil samples were collected from 0-20, and 20-40 cm depth using auger. A total of 6*2 = 12 soil
samples were collected for both dumping sites separately. A composite soil samples were also
collected from control areas near the dumping sites where wastes were not dumped separately
from the depths. The heavy metals were analyzed using AAS. The results showed that the mean
concentration were in the order of Zn>Mn>Cu>Fe>Pb>Co>Cd> Ni>Cr at Selate and Zn >
Fe>Mn>Cu>Pb>Cd>Ni>Co>Cr at Kile. The pH values ranged from 8.17-8.19 and 7.78-8.18
for the soil from old and intermediate dumping sites respectively at Selate and it was also similar
for the Kile site. Concentrations of the heavy metals were higher in soils from old and
intermediate waste dumping areas at 0-20 cm and 20-40 cm depth. Concentrations of heavy
metals in soil from dumping sites were higher than in soil from control sites. At both dumping
sites concentration of heavy metals were below the acceptable range of deferent standards. pH
of the soil was statistically correlated with most of heavy metals. Even though the concentrations
of heavy metals were below the acceptable range, rule and regulation of waste treatment system
and recycling of waste should be applied for sustainable use of the resources and environmental
quality.
