No abstract

The potentials of the invasive duckweed species, Lemna paucicostata to remove pollutants from aquatic environment was tested in a constructed wetlands as an ecological based system for the phytoremediation of petroleum hydrocarbons in crude oil-contaminated waters within 120 days. Total petroleum hydrocarbons in wetlands and tissues of duckweed were analyzed using gas chromatography with flame ionization detector following established methods while the experimental data were subjected to the first-order kinetic rate model to understand the remediation rate of duckweed in wetlands. L. paucicostata effected a significant (F = 253.405, P < 0.05) removal of hydrocarbons from wetlands reaching 97.91% after 120 days. Assessment on the transport and fate of hydrocarbons in duckweed indicated that L. paucicostata bioaccumulated less than 1% and significantly biodegraded 97.74% of hydrocarbons in wetlands at the end of the study. The experimental data reasonably fitted (r 2 = 0.938) into the first-order kinetic rate model. From the result of the study, it is reasonable to infer that L. paucicostata is an effective aquatic macrophyte for the removal of petroleum hydrocarbons in moderately polluted waters. The expansion of the chemical industry after the dawn of the industrial age has significantly increased the levels of contaminants entering the natural and human environment. Among the many chemical industries, the petrochemical industry is a major player in the global energy landscape despite significant investment and interest in alternative energy. Today, petroleum remains a significant energy demand in modern society. In spite of all the necessary safety and precautionary approach in the petroleum industry, oil spill is an inevitable occurrence in the production, transport, processing and consumption of crude oil 1,2. The continuous advancement in offshore exploration has increased the level of exposure of hydrocarbons into aquatic environment, particularly freshwater, creating a cascade of negative impact on organisms relying on freshwater resources 3,4. Oil spills in water leads to extensive damage of water resources including sensitive habitats. It suffocates aquatic life and renders water unfit for communal and domestic use 5. Over the years, various technological approach has been developed for the treatment of oil spill in marine and coastal waters, as well as rivers, streams, wetlands, swamps and lakes 6-9. Chemical methods involving the application of dispersants and in situ burning have unintended consequences despite the success recorded with such application 8,10. The unintended effects with the application of chemicals for oil spill cleanup have given opportunities to the development of biological and nature-based solutions over the past three decades for the remediation of contaminants in aquatic environment 7,11. The usefulness of plants in the biological remediation of contaminants has been expanding over the years. Several species of plants with the potentials to remove a wide range of contaminants fro...

No abstract

Environmental pollution in the oil and gas industry is the unintended but inevitable consequences of oil and gas exploration and production. Over the years, different strategies have been implemented for the remediation of oil-polluted waters. The increasing call for the use of ecologically based solutions for remediation have intensified the quest for engineers, researchers and scientists to find pragmatic solutions from the natural world. Among the several biological application for the remediation of petroleum-polluted environment, aquatic macrophytes are becoming a promising and ecological based solution for the removal of hydrocarbons pollutants in water. Pistia stratiotes, - a monotypic genus in the family Araceae, is a floating aquatic macrophyte with extensive application in the phytoremediation of organic pollutants, heavy metals and sparingly in agrochemicals, pharmaceuticals and personal care products, nanomaterials, radioactive materials and petroleum hydrocarbons in wastewater effluents and aquatic environment. The dearth of studies on the application of water lettuce for the remediation of petroleum hydrocarbons and oilfield chemicals creates a gap in the potentials of the plant for long and short-term assessment of hydrocarbon uptake, removal and degradation in contaminated waters. There is need for laboratory and field trials on the application of P. stratiotes to remediate hydrocarbons and other related pollutants in oil and gas exploration to elucidate the effectiveness and efficiency of the plant as a sound ecological base approach for sustainable remediation of hydrocarbons in a polluted environment.

The comparative study of RENA, Mycoremediation and combination of the two techniques were carried out to determine their ability in the degradation of selected heavy metals (Cadmium, Chromium, Nickel, lead, Zinc, Manganese and Iron) in a Crude oil impacted soil. Three different plots for each technique and control were each spiked with 7.5 Litres of Bonny Light crude Soil Samples were taken at 0-15cm and 15-30cm depths for each of the techniques and control at 0, 4, 8, 12, 16 and 20 weekly intervals for heavy metal analyses. Results indicated that in the plots treated with RENA, Mycoremediation and combination of the two techniques, Lead (Pb) concentration was degraded by 55.9%,65.8%,85.1% respectively compared with control plots that gave 23.7% reduction of Pb. The percentage degradation of Manganese by RENA, Mycoremediation and Myco/RENA was 57.3, 64.3, 83.1 respectively while control plots recorded 26.1% Mn degradation. Concentration of Ni was reduced by 57.8% by RENA, 64.2%, by Mycoremediation and 85.6% by the combination of the two techniques (Myco/RENA) while in the control plots Ni was reduced by 27.89%. Concentration of Cd was reduced by 56.7% 65.6%, 88.7% by RENA, Mycoremediation and Myco/RENA respectively. The control plots recorded 26.1% Cd degradation. This was similar trend observed for other heavy metals studied. Thus the combination of the two techniques (Myco/RENA technique) gave a promising result in the degradation of all the heavy metals studied in Crude Oil Impacted soil.