SINGLE AND COMBINATORIAL ATTENUATING POTENTIALS OF PHYTO-EMULSIFIED AND NON-IONIC SURFACTANTS ON CRUDE OIL IMPACTED SOIL

This study investigated the Single And Combinatorial Attenuating Potentials Of Phyto-Emulsified and Non-Ionic Surfactants on Crude Oil Impacted Soil. Crude oil highly impacted soil excavated from an oil spill site at Obeche community in Ogba/Egbema/Ndoni Local Government Area of Rivers State, Nigeria was used. Attenuation was induced using phyto-emulsified surfactant (Costus afer stem) and chemical surfactant (Triton x-100). The pH value of polluted soil sample (Cell A) was observed to be increased (6.81± 0.52) when compared with other cells that were amended. A significant reduction was observed in cell D (5.80 ± 0.00) amended with Costus afer + Triton x-100. The result of the soil electrical conductivity shows a significant difference (P≤ 0.05) when cell A is compared with other cells. Only cell C amended with 3ml of Triton x-100 had a lower value of 31.67 ± 1.52 when compared with cell A (polluted soil sample) (76.67 ± 1.52). All the other cells had higher values of 339.67 ± 5.50, 233.67 ± 4.04 and 134. 67 ± 2.51 respectively when compared with cell A (76.67 ± 1.52). After 60 days of incubation with the amendments used, only cell B amended with 200g of Costus afer had no significant difference (p≤ 0.05) when compared with cell A for total organic carbon (%) content were as others did. The same trend was observed for the total nitrogen (%) content where all the cells except cell B was significantly different (p≤ 0.05) when compared with cell A. Cells C and D had higher values of 0.32 ± 0.00 and 0.26 ± 0.07 respectively. For PO43- (mg/kg) and NO-3 (mg/kg) all the cells were significantly different (p≤ 0.05) and there was a recognized reduction in their values when compared with the control sample (Cell A). Organic Sulphur (mg/kg) value reduced exponentially but not significantly in all the cells (0.10 ± 0.00) when compared with the control cell (A) (15.00 ± 0.00). A significant difference (p≤ 0.05) when cell A is compared with the other cells was observed for the total PAH (mg/kg) concentration and all the other cells amended had a decrease in their total PAH (mg/kg) concentration with cell D having the highest reduction (1.77 ± 0.02) followed by cell B (4.74 ± 0.02) and cell C (5.97 ± 0.55) when compared with the control sample i.e cell A which has the value of 6.85 ± 0.01. All the cells amended were significantly different (p≤ 0.05) except for cell C (CISS + 3ml Triton x-100) for the TPH (mg/kg) and THC (mg/kg) concentration when compared with the control sample (cell A). All the cells amended had reduction in their TPH (mg/kg) and THC (mg/kg) concentration with the same reduction pattern observed with total PAH (mg/kg) concentration also observed here. In all the heavy metals quantified, there is a significant difference at p≤ 0.05 when all the amended cells (B to D) are compared with the control cell (A). For Pb (mg/kg), the concentration of all the cells amended significantly decreased with cell C (CISS + Triton x-100) having the lowest concentration of 1.52 ± 0.02 when compared with the control cell (11.31 ± 0.15). For Cu, Cd and Ni, (mg/kg) all the amended cells were seen to be reduced in their concentrations when compared with the concentration of the control sample. For Mn, the concentrations of the amended cells were seen to be high when compared with the concentration of the control sample. These results indicates that amendment with Costus afer stem alone and in combination with Triton x-100 proved to be very efficient materials in the cleanup of crude oil polluted soil.