Heavy Metal Characteristics of Soils at the Municipal Solid Wastes Dumpsite at Uyo Metropolis, Akwa Ibom State, South-South, Nigeria

Abstract

These findings documented the heavy metal contents of soil at dumpsite and soils at 10, 20 and 800m outside the dumpsite, during the wet and dry seasons in the vicinity of the municipal solid wastes dumpsite at Uyo metropolis, Akwa Ibom State, South - South (SS) Nigeria. The soil samples were analyzed for heavy metals Fe, Mn, Cr, Ni, Cd, Pb and Zn. The heavy metal contents recorded for the dumpsite soil and for soils at 10, 20 and 800m outside the dumpsite in both seasons agreed with the World Health Standard (WHO). The heavy metal contents recorded for the dumpsite soil in both seasons; Pb (9.90 and 8.70 )mg/kg, Zn (137 and 146 ) mg/kg, Ni (12.56 and 11.82 ) mg/kg, Cr (3.60 and 4.05)mg/kg, Cd (9.05 and 12.2) mg/kg, and Mn (94.0 and 91.2  ) mg/kg  were significantly (P<0.05) higher than the control values; Pb (3.78 mg/kg), Zn (50.90 mg/kg), Ni (2.19 mg/kg), Cr (1.06mg/kg), Mn (44.27mg/kg) and Cd (1.09 mg/kg).  Also, soils sampled from 10 and 20m east of the dumpsite  in both seasons showed a significant (P<0.05) increase in Pb, Zn, Ni, Cr, Cd and Mn contents compared with the control.  These mean values agreed with the mean concentrations measured for the dumpsite soil samples in both seasons. However, soils from 10 and 20m west, south and north of the dumpsite recorded heavy metal contents which agreed with the control results in both seasons. These findings revealed that the dumpsite has a potential effect on the ambient soil characteristics. Particularly soil located east lowland of the dumpsite. Therefore, the government of Akwa Ibom State should set up standard solid wastes recycling and reusing plants within the state to convert the different metal containing wastes generated within the metropolis into useful products. This will minimize heavy metal contamination in the soil in future.

KEY WORDS: Solid wastes, dumpsite area, heavy metals, soil, Uyo, Nigeria.