Samuel Ebinum OSEJI

The extent of groundwater and soil pollution arising from an open dumpsite was carried out to examine the physico-chemical and trace metals status in Osubi, Delta State. Twenty two (22) soil samples were collected randomly at depths of 0-15 cm, and 15-30 cm and one control (natural environment). While sixteen (16) groundwater samples were collected through random sampling technique for analysis. The soil samples were digested into solution using aqua regia and analyzed using the Atomic Absorption Spectrometer (AAS), [buck model 210 VGP]. The results of the analysis was then subjected to statistical treatment (One-way Analysis of Variance), Spearman’s Correlation Coefficient and Pollution Load Index to ascertain significant difference among the trace metals, association and status of contamination/pollution respectively. Result from the analysis showed that both groundwater and soil samples in the study area is acidic with pH values ranging from 5.28-5.96, and 2.30-6.20 respectively. The level of average metal contents obtained from soil samples at the different depths is as follows: Arsenic; 10.58-20.4 mg/kg, Manganese; 1.42-3.58 mg/kg, cadmium; 1.05-3.46 mg/kg, Chromium; 1.61-4.55 mg/kg, Lead; 2.11-3.71 mg/kg, Zinc; 5.77-15.5 mg/kg, Copper; 1.69-3.23 mg/kg, Cyanide; 0-0.005 mg/kg, Nickel; 1.31-4.59 mg/kg and Vanadium; 1.24-0.3.95 mg/kg which were much higher than that of the control. The correlation result between the analyzed parameters in hand-dug wells and borehole samples, revealed positive and negative correlation coefficients at r(0.01) and r(0.05) indicating strong association between them, which probably reflects their related source of contamination. However, correlation was also not significant among some parameters in the groundwater samples indicating an uncommon source of contamination. Calculated pollution load index (PLI) indicated that location SS8 had maximum pollution load index of 2.15 and a minimum pollution load index value of 1.80 was obtained at location SS6. The order of pollution load index per location for the sediments is as follows: SS8 > SS5 > SS9 > (SS4=SS7=SS10) > SS2 > SS3 > SS6. While the order of contamination factor (CF) revealed among the heavy metals is as follows: Mn> V > Cr > Ni > Cd > Zn > As >Pb> Cu. The results revealed that both the groundwater and soil were slightly- moderately contaminated. It is hereby reco mended that groundwater monitoring and proactive steps be taken to minimize gradual accumulation of these contaminants from the dumpsite.