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Large scale landfarming experiments, using an extensive range of treatments, were conducted in the Niger-Delta, Nigeria to study the degradation of oil in contaminated soils. In this work the effect of nutrient addition, biosurfactant, Eisenia fetida (earthworm) enzyme extract, bulking and sorption agents and soil neutralization were tested. It was found that these treatments were successful in removing up to 53% of the total petroleum hydrocarbon in the soil within 16 weeks. A comparison between treatments demonstrated that most were no more effective than agricultural fertilizer addition alone. One strategy that did show better performance was a combination of nutrients, biochar and biosurfactant, which was found to remove 23% more Total Petroleum Hydrocarbons (TPH) than fertilizer alone. However, when performance normalized costs were considered, this treatment became less attractive as a remedial option. Based on this same analysis it was concluded that fertilizer only was the most cost effective treatment. As a consequence, it is recommended that fertilizer is used to enhance the landfarming of hydrocarbon contaminated soils in the Niger Delta. The attenuation rates of both bulk TPH and Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG) fractions are also provided. These values represent one of the first large scale and scientifically tested datasets for treatment of contaminated soil in the Niger Delta region. An inverse correlation between attenuation rates and hydrocarbon molecular weight was observed with heavy fractions showing much slower degradation rates than lighter fractions. Despite this difference, the bioremediation process resulted in significant removal of all TPH compounds independent of carbon number.

Aim: This study evaluated the efficacy of aqueous extract of Acalypha godseffiana leaves against H2O2-induced oxidative stress and organ damage in wistar rats by measuring hepatotoxic biomarkers, nephrotoxicity and status of the antioxidant defense system. Study Design: Twenty-five rats, randomly divided into five groups, were used in this study. Fresh leaves of Acalypha godseffiana leaves were air-dried, ground into fine powder and used in the preparation of an aqueous extract. Place and Duration of Study: Department of Biochemistry, and Department of Physiology, University of Port Harcourt, Nigeria between November 2020 and April 2021. Methodology: Oxidative stress and toxicity was induced using 5ml of 6% H2O2. Treated rats received A. godseffiana aqueous leaf extract at various doses: 100, 200 and 400 mg/kg b.w. The rats were fasted for 24 h prior to sampling and then mildly anesthetized with chloroform. Biochemical assays and histological studies were conducted at days 14 and 28 respectively. Results: There was significant (P<0.05) increase in plasma levels of AST in the H2O2 -treated group as compared with the negative control which recorded 105.00 ± 3.00 and 107.50 ± 7.50 (µ/L) at day 14 and 28 respectively. The H2O2 group showed significant (P<0.05) increases in plasma levels of K-, Na+, Urea, Cl- and HCO3- as compared with the negative control. A. godseffiana-treated rats showed significant (P<0.05) increase in serum levels of GSH, Catalase and SOD. Photomicrographs obtained showed histologically distorted liver and kidney tissues in the H2O2 group at days 14 and 28. Overall, the architecture of the liver was preserved by the administered aqueous leaf extract of A. godseffiana. Conclusion: Data obtained from this study suggest that A. godseffiana leaves exhibit promising antioxidant and hepatoprotective potency, and consequently has ameliorative effects against H2O2-induced oxidative stress and organ damage in wistar rats.