Evaluation of heavy metals’ contamination of ground water and soil around Mbodo-Aluu dumpsites for sustainable agriculture

Abstract

Evaluation of heavy metals contamination in soil and groundwater around Mbodo-Aluu dumpsites was carried out at three foremost sites; farmlands around the dumpsite, Egbelu River, and some Boreholes in Ogbogoro town. The water sample was obtained in triplicates at a hand-dug pit at 10m depth; borehole water was used as control while soil samples were taken randomly at 0-15cm and 15-30cm depth. Standard procedure was adopted in determining the physicochemical properties of groundwater and soil samples; heavy metal concentration was determined by Atomic Absorption Spectrophotometer. Results of the analysis showed pH of 4.2 around the dumpsite and 6.2 in the control sample. The conductivity of 11 and 40 uS/cm deviated from NIS/WHO set the standard; Chloride and Nitrate content around the dumpsite were 63.81mg/Land 56mg/L, while the control sample was 23mg/L and 0.22mg/L, respectively. Heavy metal analysis showed high concentrations of Cadmium (0.86mg/L), Nickel (0.42mg/L), and lead (0.017mg/L) around the dumpsite. In the control sample, lead and arsenic were absent. Meanwhile Chromium concentration was 0.219mg/L and 0.102mg/L for both samples. The result of soil analysis in this study showed pH of 3.41 and 5.89 as Pb concentration varied between 0.08 and 11.98 mg/L, and Cadmium ranged from 2.3-3.71mg/L, result also revealed that Nickel and chromium concentrations ranged from 0.05 - 0.38 mg/L and 0.07- 0.56 mg/L. An increase in heavy metals contamination in groundwater and soil can be linked to human activities rather than normal. It is therefore recommended that dumpsites be properly managed, and hazardous wastes separated before disposal.