Assessment of soil properties in abandoned dumpsites in Aba Metropolis, Abia State, Nigeria

Solid waste management is an environmental challenge affecting all spheres of environment including soil. However, little is known about the status of soil under abandoned dumpsites. The present study investigated the soil properties in the abandoned dumpsites of different ages in Aba Metropolis namely Umunwankwo (25 years) and Umuigwe (3 years) dumpsites. Ten 10m x10m quadrats were delineated in each dumpsites and relatively disturbed forest (RDF) i.e. control plot. A soil sample was collected in each quadrat using soil auger at the topsoil (0-15cm depth); thus, 10 soil samples were collected from each dumpsite and RDF. Soil samples were collected into well-labelled polythene bags and brought into the laboratory. The soil samples were air-dried and carefully sieved with 2mm diameter mesh to separate the soil from stones. Thereafter, the soil samples were taken to the laboratory for analysis to determine the levels of the physical and chemical properties in the dumpsites and RDF using standard techniques. Descriptive and inferential statistics were used for data analysis. Results showed that sand content was predominantly high in the study area and silt content (3.15±0.6%), Organic C (3.33±0.6%), total N (0.33±0.1%) and K (0.50±0.2 meq/100g) were significantly highest in the abandoned dumpsite of 3 years while P was significantly higher in the abandoned dumpsite of 25 years. Heavy metals were highest in the abandoned dumpsite of 3 years except Cu which was highest in the abandoned dumpsite of 25 years (28.06±7.0 mg/kg). The physico-chemical properties of soil were higher in the dumpsite than the RDF and varied significantly among the plots at p<0.05. The study concluded that dumpsites have the capability of releasing heavy metals into the soil ecosystem but increase the soil nutrients. The study recommended that the solid wastes should be sorted to remove those that have potentials of releasing heavy metals.