ABSTRACT
Samples collected for physico-chemical and heavy metal analysis from different communities in Ogoni land include soil, river sediments and surface water samples. Ten surface water samples were collected using random sampling technique for analysis, while ten soil samples were collected randomly at depths of 15cm to 30 cm, including two controls (natural environment). Also, ten river sediments were collected including two controls. The samples were collected in order to ascertain the level of contamination/pollution of the study area as a result of oil spill and other anthropogenic activities within the study area. The result of the analysis showed pH (5.04- 5.6), Zn (8.58-11.89mg/kg), Fe (111.45-281.55mg/kg), Cu (21.44-29.72mg/kg), Cr (49.31- 68.36mg/kg), Ni (32.16-44.58) and Pb (16.08-22.29) for the river sediments; pH (4.99-6.14), Mn (17.14-27.97mg/kg), Ni (28.56-46.62mg/kg), Fe (214.2-349.65mg/kg), Cu (19.04-31.08mg/kg), Cr (40.99-71.48mg/kg) and Pb (14.28-23.31mg/kg) for the soil samples. Analysis of the water samples showed pH (5.29-5.68), Electrical conductivity (106-421 uS/cm), turbidity (0.55- 50.52NTU). Zn (6.04-24mg/l), Cu (2.86-11.37), Cr (8.48-33.68mg/l), Mn (19.19-76.2mg/l), Fe (36.36-144.4mg/l), Ni (5.51-21.89mg/l) and Pb (0.99-3.92mg/l). The results of the analysis were further subjected to statistical treatment such one analysis of variance (ANOVA), spearman correlation coefficient, pollution load index, Dendrograms etc to ascertain their spatial relationship between the samples. The ANOVA results for river and dry soil sediments indicated very strong significant difference (at p<0.01) between control and sediments in all parameters except for pH.correlation results revealed positive and negative correlation coefficients at r(0.01) and r(0.05) indicating strong relationship between them, which probably reflects their related source of contamination. Concentration maps generated for the area showed higher concentrations of Fe, Pb and Zn around the central and north eastern parts of the study area. Calculated pollution load index indicated that location SS2 had a maximum pollution load index of 3.5, and a minimum pollution load index value of 2.6 was obtained at location SS3 and SS6. The overall results revealed that both the surface water and soil are averagely contaminated/polluted. It is hereby recommended that proactive steps should be taken to minimize oil spillage and further measures also taken to efficiently clean the already oil-polluted surface water and soil which has hampered fishing and farming activities that has been the age long source of livelihood in Ogoni land.
