USE OF ALKYL POLYGLYCOSIDES IN THE REMEDIATION OF HEAVY METALS FROM HYDROCARBON CONTAMINATED SOILS

Heavy metal contamination of soil is a global issue because of the accumulation of these compounds in the environment, endangering human health, plants, and animals. This research investigated surfactant enhanced remediation of heavy metals such as of Fe, Zn, Pb, Ni, Cr, and Cu in hydrocarbon contaminated soil samples from Eneka, Ozuoba and Rukpokwu. The soil samples were contaminated with medium and light crude oil, and the concentrations of heavy metals were analysed with Atomic Absorption Spectroscopy. Results obtained from the medium crude contaminated soil samples before remediation showed: Cu: 5.82mg/kg, Fe:11897.00 mgkg-1, Zn :129.00 mgkg-1, Pb: 6.80 mgkg-1, Ni:11.60 mgkg-1, Cr: 20.70 mgkg-1 for soil samples from Eneka. The metal concentrations were reduced to 3.80 mgkg-1, 2013.00 mgkg-1, 29.40 mgkg-1, < 0.012 mgkg-1, <0.008 mgkg-1, and <0.005 mgkg-1 respectively after remediation. The results of the soil samples from Ozuoba were: Cu: 3.04 mgkg-1, Fe: 7197.00 mgkg-1, Zn: 51.80 mgkg-1, Pb: 3.10 mgkg-1, Ni: 11.90 mgkg-1, Cr: 37.90 mgkg-1 before remediation. The concentrations of the metals were reduced to 1.27 mgkg-1, 2017.00 mgkg-1, 19.40 mgkg-1, 0.012 mgkg-1, <0.008 mgkg-1 and < 0.005 mgkg-1 respectively after remediation. The results of soil samples from Rukpokwu were: Cu: 3.56 mgkg-1, Fe: 4188.00 mgkg-1, Zn: 111.00 mgkg-1, Pb: 1.04 mgkg-1, Ni: 9.50 mgkg-1, Cr: 34.50 mgkg-1 before remediation. The concentrations of the heavy metals were reduced to 1.57 mgkg-1, 2034.00 mgkg-1, 16.00 mgkg-1, <0.012 mgkg-1, <0.008 mgkg-1 and <0.005 mgkg-1 respectively after remediation. The soil samples contaminated with light crude showed the following results before remediation; Cu: 5.04 mgkg-1, Fe: 10495.00 mgkg-1, Zn: 97.50 mgkg-1, Pb: 4.70 mgkg-1, Ni: 8.44 mgkg-1, Cr: 19.00 mgkg-1 for Eneka:. The concentrations of the metals were reduced to 2.86 mgkg-1, 2080.00 mgkg-1, 27.20 mgkg-1, <0.012 mgkg-1, <0.008 mgkg-1 and <0.005 mgkg-1 after remediation. The results of soil samples from Ozuoba are as follows: Cu:1.13 mgkg-1, Fe: 5504.00 mgkg-1, Zn:43.00 mgkg-1, Pb: 2.70 mgkg-1, Ni: 12.10 mgkg-1, Cr: 17.20 mgkg-1 before remediation. The concentrations were reduced to 0.21 mgkg-1, 1909.00 mgkg-1, 12.20 mgkg-1, <0.012 mgkg-1, <0.008 mgkg-1 and <0.005 mgkg-1 after remediation. The soil samples from Rukpokwu showed the following results before remediation: Cu: 2.43 mgkg-1, Fe: 4572.00 mgkg-1, Zn: 65.30 mgkg-1, Pb: 0.86 mgkg-1, Ni 13.70 mgkg-1, Cr: 20.70 mgkg-1. These concentrations were reduced to 0.26 mgkg-1, 1841.00 mgkg-1, 15.30 mgkg-1, <0.012 mgkg-1, <0.008 mgkg-1, and <0.005 mgkg-1 after remediation. The results of this study showed that the concentrations of Pb, Ni, and Cr were removed to below the detection limit of the equipment. Fe and Zn showed a very high degree of success, achieving a 60% to 83% reduction in all soil. The removal of Cu from the Eneka sample showed the least removal tendency of 33.51% in medium crude contaminated soil and 43.25% in light crude contaminated soil. The use of alkyl polyglucoside surfactant enhanced the solubilisation and surfactant-metal complexation, resulting in the removal of these heavy metals from hydrocarbon contaminated soils.