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Ecotoxicological effects of the discharge of Nigerian petroleum refinery oily sludge on biological sentinels were examined. The ecotoxicological effects examined included acute toxicity tests on Nitrobacter sp., fresh water shrimp (Desmoscaris trispinosa) and brackish water shrimp (Palaemoneles africanus) from the aquatic environment. It also covered chronic toxicity tests on microbial nitrogen transformation activity in soil and the growth of the terrestrial fauna, earthworm (Apporectoda longa) in pristine soils spiked with predetermined concentrations of the sludge. Analysis of the Nigerian petroleum refinery oily sludge used in this study indicated that the sludge is slightly acidic with a high total petroleum hydrocarbon (TPH) content of 340,000 mg/kg made up mainly between 10-40 carbon unit compounds. The sludge reduced the growth of Nitrobacter sp. in aqueous medium and also caused chronic effect on microbial nitrogen transformation activity in soil because it exceeded the 25% inhibition limit for chemicals with the potential to cause chronic effects on soil microbial activities. Similarly, the sludge exhibited toxicity on fresh and brackish shrimp. The freshwater shrimp was however more affected with an LC 50 of 1097.375 ± 0.62 mg/kg when compared with an LC 50 of 1590. 37±0.92 mg/kg obtained for the brackish water shrimp. It also reduced the growth rate of the earthworm (A. longa) progressively as the sludge concentration increased.

Aim: Over dependence on fossil fuels has triggered environmental and economic concerns, creating an ultimate need to redirect towards renewable energy options. Hence, the study on biodiesel production from algal biomass. Study Design: Modified open pond culture system was applied in the biomass culture and growth was  monitored via pH and turbidity. Place and Duration of Study: Study was done in the laboratory of the Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun between June 2020 and July 2021. Methodology: Soxhlet extraction was applied in algal oil extraction. Alkali-mediated transesterification of algal oil blends into biodiesel was conducted. Biodiesel blends were characterized physically and spectroscopically for fuel properties and chemical position. The synthesis and fuel properties of biodiesels from three micro algal species: Chroococcus sp, Ankistrodesmus falcatus, and Chlamydomonas reinhardtii were conducted. Due to low algal oil yield, characterization of four types of hybrid oils were prepared: 100 percen(%)t lavender oil (100LO), 10% Ankistrodesmus falcatus oil plus 90% LO (10AN90LO), 10% Chlamydomonas reinhardtii oil plus 90% LO (10CHL90LO), and 10% Chroococcus sp oil plus 90% LO (10CHR90LO). Results: The synthesis and fuel properties of biodiesels from the micro algal species: Chroococcus sp, Ankistrodesmus falcatus, and Chlamydomonas reinhardtii gave a percentage yield of algal oil of 29.6%, 23.4% and 15.5%, respectively. The percentage yield of biodiesel from 10AN90LO, 10CHL90LO, 10CHL90LO was 66.7%, 61.7% and 50.0%, respectively. Gas Chromatography-Mass Spectrometry(GC-MS) analysis revealed presence of four fatty acid methyl and vinyl esters namely; hexadecanoic acid methyl ester, octadecadienoic acid methyl ester, methyl stearate, carbonic acid eicosyl vinyl ester and carbonic acid, tetradecyl vinyl ester. Fourier transform infrared spectroscopy(FTIS) confirms that chemicals produced are esters. Conclusion: Fuel properties of biodiesel from these selected algal strains appear appreciable when compared to standard limits. Blends with petroleum diesel showed great potential for use in diesel engines.

Aim: The study assessed the bio treatability of the petroleum refinery sludge in contaminated soils by indigenous bacterial communities and the effects of the sludge contamination and bio stimulants on the biodiversity and dynamics (rate of change) of the bacterial communities involved in the biodegradation of the sludge, using the molecular biology technique, Denaturing Gradient Gel Electrophoresis (DGGE). Study Design: The randomnized block design was used for the study. Place and duration of the Study: The research was conducted in the biology laboratory of Flinders University, Adelaide, South Australia. Methodology: The percentage of total petroleum hydrocarbons (TPH) degraded and the bacterial load in the test microcosms was assessed tri-weekly for 12 weeks. The percentage TPH was assessed using Gas chromatography, while the bacterial count was determined as gene copies using the culture independent molecular tool, quantitative real-time PCR (qRt-PCR) analysis. The effects of the experimental treatments on the biodiversity and dynamics (rate of change) of the bacterial communities involved in the biodegradation of the sludge in the soils was determined by the culture-independent molecular biology technique, DGGE. Moving Windows Analysis (MWA) and Shannon Weaver diversity index were used to determine the dynamics (rate of change) and biodiversity of the bacterial communities respectively. Results: Results obtained for the Moving Window Analysis (MWA) which is used to determine the dynamics (Dy), or rate of change of the bacterial communities, showed that, the 1% and 5% sludge contaminated soils biostimulated with compost, recorded the highest Dy of 86.0 ± 1.90% and 87.0 ± 2.20% respectively.NPK biostimilated soil microcosms however recorded a lower Dy of 33.75± 3.20 and 32.50 ± 4.68% for 1% and 5% sludge contamination respectively. The biodiversity of the bacterial communities expressed as Shannon -Weaver index (H1), recorded the highest value of 2.76 ±0.02 for the compost biostimulated microcosm in the 1% sludge treatment, while for the 5% sludge contamination, the treatment with NPK and surfactant enhanced the bacterial biodiversity most with a value of 2.76 ±0.07%. In the test soils with 1% sludge contamination, bio stimulation with NPK gave the highest % TPH degradation (78.25%) while the treatment with NPK and Triton-X 100 had the highest TPH degradation (46.55%) for the 5% sludge contaminated soils. There was insignificant difference in the % sludge degradation between the control and other treatments at P > 0.05 and F = 4.07 for the 1% sludge treated soils, while for the soils treated with 5% sludge there was significant difference between the control and other treatments at P < 0.05 and F= 4.07. Conclusion: Bacteria species identified in the sludge by molecular biology techniques included; Pseudomonas sp. ITRI77, Uncultured Thauera sp., Uncultured Pseudomonas sp., Flavobacterium sp., Bacillaceae bacterium, Uncultured soil bacterium, Clostridium sp., most of which are Gram negative. Biostimulation with compost enhanced a higher biodiversity (H i) and dynamics (Dy) of the bacterial communities involved in the biodegradation of the sludge. Though the NPK treated soils enhanced the biodegradation of the sludge most, degradation started declining by the 9th week while that of compost continued to rise steadily till the 12th week. Results obtained indicate that compost is as good as NPK in the biodegradation of petroleum sludge especially at 1% sludge contamination, since there was no statistical difference between the % TPH degraded and the use of compost is environmentally friendly and economically sustainable.

Aim: The aim of the study is to assess the sublethal (chronic) Ecotoxicological effects ofpetroleum refinery sludge pollution on the biota of the terrestrial environment using the effects on bacteria nitrogen transformation activity and growth rate of the soil fauna, Earthworm (Aporrectodea longa)  as bioindicators. Place and Duration of Study: Department of Environmental Management and Toxicology, Federal University of Petroleum Resources, Effurun, between 2017 and 2018. Methodology: The OECD TG 216 (2000) test method was used to determine the chronic effects (% inhibition and EC50) of the petroleum sludge on the nitrogen transformation activity of Nitrobacter sp. in the soil, while the methods of Sandoval et al. [13] and OECD, 207 was used for the chronic effects of the sludge on the growth rate of the earthworms. Bioconcentration factor (BCF) of the sludge in the earthworms was also determined. Both tests were conducted for 28 days. Results from the test with multiple concentrations were analyzed using a regression model (ANOVA). EC5O was also determined using the Probit analytical software. Analyses weredone using ASTM methods. Results: Analysis of the Nigerian petroleum refinery sludge used for this research indicated that the sludge wasacidic with a pH value of 5.91and had a high TPH content of 340,000 mg/kg made mainly of between 10-40 carbon unit compounds. There was a progressive increase in the percentage (%) inhibition of the nitrogen transformation activitiesof the bacteria, from 18.0% (3125 mg/kg) to 79.30% (5000mg/kg) with increase in concentration and time. The effective concentration that decreased 50% (EC50) of the nitrogen transformation activity was 13761.059 mg/kg. The growth rate of the test earthworms decreased from 9.19x103 g/day (375 mg/kg) to 3.55x103 g/day (3000 mg/kg) for the test period. The BCF decreased from 5.168 (375 mg/kg) to 1.22 (3000 mg/kg) in the earthworms, while the EC50for the earthworms was 825.02mg/kg as the concentration of the sludge increased with time. Conclusion: The sludge inhibited the nitrogen transformation activity of Nitrobacter sp. because it exceeded the 25% inhibition limit for chemicals with the potential to cause chronic effects on soil microbial activities as specified in OECD TG 216. Similarly, the sludge reduced the growth rate of the earthworm progressively as the sludge concentration increased in relation to the control. Bioaccumulation factor also increased with increasing sludge concentration and time.