Assessment of the Impact of Waste Dumpsite on Soil Quality in Nekede, Imo State, Nigeria

This research was carried out to assess the physicochemical properties of the soil and concentration of heavy metals (lead, copper, zinc and nitrate) in waste dumpsite Ihiagwa Imo State, Nigeria. In other to assess the physicochemical properties of the soil in the study area , soil samples were collected from three (3) points labeled Point 1, Point 2 and Point 3(Control point) with depth ranging from 0-15 (top soil), 15-30 (Sub-soil), and 30-45 (Bottom). The physicochemical parameters and heavy metal results shows that the pH ranges from 5.756(sub soil) to 6.009 (top soil) at Point 1, from 5.722(sub soil) to 5.976(top soil) at Point 2, from 5.137(sub soil) to 6.147(bottom) at Point 3. The electrical Conductivity ranged from 80.50µs/cm (top soil) to 162.9µs/cm (bottom) at point 1, from 52µs/cm (top soil) to 90.1µs/cm(sub soil) at point 2, from 58.4µs/cm(sub soil) to 95.9µs/cm (bottom) at point 3. The bulk density ranged from 1.396g/cm3(top soil) to 1.462g/cm3 (bottom) at point 1, from 1.375g/cm3 (top soil) to 1.459g/cm3 (bottom) at point 2, from 1.399g/cm3 (top soil) to 1.511 (bottom) at point 3. Copper (Cu) ranged from 0.148Mg/100g (top soil) to 0.928Mg/100g (bottom) at point 1, from 0.232Mg/100g (top soil) at point 2, from 0.092Mg/100g (bottom) to 0.489Mg/100g (top soil) at point 3. Zinc (Zn) ranged from 0.12Mg/100g (bottom) to 0.21Mg/100g (sub soil) at point 1, from 0.098Mg/100g (top/sub soil) to 0.217Mg/100g (bottom) at point 2, from 0.026Mg/100g (bottom) to 0.188Mg/100g ( top soil) at point 3. Lead (Pb) ranged from 0.138Mg/100g (top soil) to 1.026Mg/100g (bottom) at point 1, from 0.282Mg/100g (top soil) to 0.547Mg/100g (sub soil) at point 2, from 0.084Mg/100g (bottom) to 0.442Mg/100g (top soil) at point 3. Nitrate (NO3) ranged from 3.336Mg/Kg (bottom) to 4.87Mg/Kg (top soil) at point 1, from 3.82Mg/Kg (bottom) to 4.687Mg/Kg (top soil) at point 2, from 3.838Mg/Kg (bottom) to 5.202Mg/Kg (top soil) at point 3.The range and the mean value of the results from the three soil samples (point 1,2 and 3) were compared with the World Health Organization (WHO) Standard the pH level of the sample shows a deviation of WHO Standard, tilting towards the acidic region of the scale, the Electrical Conductivity of all samples fell above the WHO permissible limit. Nitrate level all fell below the permissible WHO limit except for P3 (top soil) which slightly falls above the permissible limit. Copper (Cu) level all fell within the WHO standard. Zinc (Zn) value all fell below the permissible WHO standard. Lead (Pb) level fells above the permissible WHO standard. The bulk density of the dump site falls within the permissible WHO standards. The statistics of soil quality in the study area shows that conductivity has the highest value of standard error of 26.36481241, 11.0021715 and 11.54647613 for each point 1, 2 and 3 respectively. Also, zinc has the least value of Standard deviation of 0.044094595, 0.068704682, and 0.081663946 respectively.