Quantification of Heavy Metals using Contamination and Pollution Index in Selected Refuse Dumpsites in Owerri, Imo State Southeast Nigeria

Many sites in urban cities are used for dumping of domestic, industrial and municipal wastes because of high human population density in the area. Most often, people use these dumpsites for growing of crops without knowing the level of heavy metal contamination in soils of these areas. This study evaluated the quantification and contamination level of heavy metals in some refuse dumpsites in communities of the State Nigeria. Three replicate soil samples were collected from the dumpsites and at 20 m away from the non - dumpsite which do not receive sewage water within the root zone of 0 – 40 cm depth using soil auger sampler. Samples were analysed for soil properties and heavy metal concentrations using standard methods. The concentrations of the studied heavy metals (Cu, Pb, Zn and Cd) were compared with the permissible limits of other countries. Results showed that in the three studied locations, soil pH at dumpsites were 40 .6%, 39.4% and 38.9% higher than the values in the control sites while soil organic carbon were higher in the dumpsites by 50.1%, 31.3% and 41.1% as compared to the control sites. Cu concentrations at the three locations were below the standard limits of United Kingdom, European Union (EU), USA and WHO. The concentrations of the studied heavy metals passed the contamination stage and therefore will pose negative effect on plant and soil environment. Use of the dumpsite for crop cultivation or as compost materials should be avoided and construction of shallow wells near these areas should be discouraged.