METAL CONTAMINATION AT DUMP SITES IN MAKURDI, NIGERIA

Abstract

This study has focused on the investigation of metal contamination by refuse dumps in Makurdi, Nigeria. Soil samples were collected from 17 dump sites and also from a forest to serve as control. Samples were pretreated, digested by aqua regia and the resulting solution analyzed for Fe, Zn, Cu, Pb and Cd using atomic absorption spectrophotometer (AAS). Result shows that the range of iron was 120 –440ppm, zinc 100-260ppm; copper16-201ppm; lead 10-115ppm and cadmium 2-30ppm; in soil from refuse dump sites while forest soil has a range of 120-300ppm for iron, 25 –150ppm for zinc, 20-50ppm for copper, 7-31ppm for lead and 0.5-3.5ppm for cadmium. The significant difference between result obtained for refuse dump sites and the forest soil indicates that refuse dump sites most probably represent point sources of metal contamination to nearby environment. This study also examined metal mobility with 0.1M HCI solution. Result shows that extraction rates (mobility) were in the order Zn>Cd>Cu>Pd> Fe which may be due to differences in geochemical behaviour of metals in the soil. Finally the concept of pollution index (Pl) of soils was applied to determine the extent of multi-element contamination caused by refuse dumps.


Keywords: Extraction rate, Makurdi, metal contamination, pollution index, refuse dumps.


[Global Jnl Geol. Sci. Vol.1(1) 2003: 85-94]