Environmental Geochemistry and Heavy Metal Assessment in Soils, Surface and Groundwater from Eastern Niger-Delta, Nigeria using Multivariate Pollution Indices

Abstract

In recent times, there have been increasing interests regarding heavy metal contaminations in the environments, apparently due to their toxicity and perceived persistency within the aquatic systems. Land and water are precious natural resources on which rely the sustainability of agriculture, industrialization and the civilization of mankind. They have been subjected to severe exploitation and contamination due to anthropogenic activities resulting from industrial effluent, refuse dumps, gas flaring, oil spillage and petroleum refining leading to the release of heavy metals into the environment. The results of the analyses indicate a low pH (3.84 - 7.74) and high concentrations of electrical conductivity (28.00 - 752.00), chloride (12.00 - 721.00) and heavy metals in the decreasing order of: Fe > Ni > Cu > Zn > Mn > Cd > V > Co > Pb > Cr > As > Hg. The heavy metal pollution index revealed that the metal pollution in the soil and water ranged from slightly polluted to very highly polluted. The poor sanitary condition coupled with the high degree environmental abuses in terms of oil spillage, gas flaring and industrial effluent in the area are responsible for the low pH, wide range in the concentration of EC, TDS, Chloride, E.coli, total coliform and heavy metals in the soil and water system in the area. Good sanitation, use of well-lined soakaway, treatment of industrial effluent before discharge and putting an end to gas flaring and oil spills are advocated. The use of environmentally friendly techniques such as bioremediation and phytoremediation in remediating the contaminated soil and water in the area is recommended.