Biodegradation of polluting oil at sea is seriously limited by the scarcity of nitrogen and phosphorus. Since water soluble sources of these elements could be ineffective in the ocean, oleophilic compounds were screened to serve as fertilizers for oil slicks. A combination of paraffinized urea and octylphosphate was found to promote oil biodegradation both in laboratory experiments and in field trials to an extent that the practical application of this principle to oil cleanup appears feasible. The tested oleophilic fertilizer supplies nutrients to hydrocarbon-degrading microorganisms selectively, and in contrast to nitrate and phosphate salts it does not trigger algal blooms.

Stimulated biodegradation of oil slicks using oleophilic fertilizers. Technical report No. 3, January-December 1972

Enhanced biodegradation of hydrophobic organic pollutants by the bacterial consortium: Impact of enzymes and biosurfactants.

Characterization of two novel strains of Pseudomonas aeruginosa on biodegradation of crude oil and its enzyme activities.

Crude oil exploration is a source of significant revenue in Africa via trade and investment since its discovery in the mid-19th Century. Crude oil has bolstered the continent's economy and improved the wellbeing of the citizenry. Historically, Africa has suffered from conflicts due to uneven redistribution of crude oil revenue and severe environmental pollution. Advancements in geophysical survey techniques, such as magnetic and gravity methods, to seismic methods, have made the commercial exploration of crude oil possible for some other countries in Africa apart from Nigeria, Angola, Algeria, Libya, and Egypt. The occurrence of organic-rich, oil-prone Type I, II, and mixed II/III kerogens in sedimentary basins and entrapment within reservoir rocks with intrinsic petrophysical properties are majorly responsible for the large deposits of hydrocarbon in Africa. The unethical practices by some multinational oil corporations have resulted in social movements against them by host communities and human rights groups. The unscrupulous diversion of public funds, award of oil blocks, and production rights to certain individuals have impaired economic growth in Africa. The over-dependence on crude oil revenues has caused the economic recession in oil-producing countries due to plummeting oil prices and global pandemic. Most host communities of crude oil deposits suffer from a lack of infrastructure, arable soils, clean water, and their functioning capabilities are violated by crude oil exploratory activities, without adequate compensations and remedial actions taken by oil companies and the government. Thus, this review examines crude oil exploration in Africa and provides insight into the environmental and socio-economic implications of crude oil exploration in Africa. Furthermore, this report highlights some recommendations that may ensure ethical and sustainable practices toward minimizing negative impacts and improving the quality of life in affected communities.

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Crude oil exploration in Africa: socio-economic implications, environmental impacts, and mitigation strategies

Modeling oil biodegradation and remediation has become an increasingly important means to predict oil persistence and explore potential in-situ bioremediation strategies for oil-contaminated beaches. Beaches involve complex mixing dynamics between seawater and groundwater. Thus, numerically predicting oil biodegradation within beach systems faces major challenges in merging highly dynamic biogeochemical conditions into microbial degradation models. In this paper, we reviewed recent advances in modeling oil biodegradation from aspects of oil phases, reaction kinetics, microbial activities, environmental conditions, and beach hydrodynamics. We identified key controlling factors of oil biodegradation, highlighted the importance of fate and transport processes on nearshore oil biodegradation, and suggested some advances needed to achieve for developing a robust numerical model to predict oil biodegradation and bioremediation within beaches. 

Modeling oil biodegradation and bioremediation within beaches

Investigation of Bacillus licheniformis in the biodegradation of Iranian heavy crude oil: A two-stage sequential approach containing factor-screening and optimization.

Petroleum contamination of marine environments due to exploitation and accidental spills causes serious harm to ecosystems. Bioremediation with immobilized microorganisms is an environmentally friendly and cost-effective emerging technology for treating oil-polluted environments. In this study, Bacillus licheniformis was entrapped in Ca alginate beads using the electrospray technique for light crude oil biodegradation. Three important process variables, including inoculum size (5–15% v/v), initial oil concentration (1500–3500 ppm), and NaCl concentration (0–30 g/L), were optimized to obtain the best response of crude oil removal using response surface methodology (RSM) and Box–Behnken design (BBD). The highest crude oil removal of 79.58% was obtained for 1500 ppm of crude oil after 14 days using immobilized cells, and it was lower for freely suspended cells (64.77%). Our result showed similar trends in the effect of variables on the oil biodegradation rate in both free cell (FC) and immobilized cell (IC) systems. However, according to the analysis of variance (ANOVA) results, the extent of the variables’ effectiveness was different in FC and IC systems. In the immobilized cell system, all variables had a greater effect on the rate of light crude oil degradation. Moreover, to evaluate the effectiveness of free and immobilized B. licheniformis in bioremediation of an actual polluted site, the crude oil spill in natural seawater was investigated. The results suggested the stability of beads in the seawater, as well as high degradation of petroleum hydrocarbons by free and immobilized cells in the presence of indigenous microorganisms.

Enhanced biodegradation of light crude oil by immobilized Bacillus licheniformis in fabricated alginate beads through electrospray technique.

Improving mass transfer rates in microbial cell immobilization system for environmental applications: Synergistic interaction of cells on crude oil biodegradation.

Radon gas emission is emerging phenomenon that poses potential danger to human health as a result of modern lifestyles. Thus, it is critical to conduct stochastic evaluations of the amount of this hazardous gas in urban areas and residential buildings to identify environmental health risks. To assess statistical radon environmental health risks, this research proposes two novel fuzzy radon hazard indices (FRHIs), FRHI1 and FRHI2.. FRHI1 can contribute to every standard, while FRHI2 can be compared to geogenic radon potential or geogenic radon hazard indices. The output indices FRHIs range from 0 (no hazard) to 100 (the highest degree of hazard). The proposed approach can serve as a circumstantially integrated standard for stochastic radon risk assessment and management, so that fuzzification can bring innovation in stochastic standards in this field. In this study, radon concentration was measured in an urban building and natural radon and emission zoning maps were created using ArcGIS software at urban and geological scales. A residential building unit located in a critical area was selected and some corrective actions were adopted to reduce radon in urban building units. The FRHI Assessment for stochastic environmental health risk evaluation showed that the initial fuzzy level for the mean value of FRHI is hazardous (for an FRHI value equal to 60.1), indicated by red. However, the Maximum FRHI level for 48 h after the installation was rather hazardous (for an FRHI value equal to 44.8), indicated by orange. After steady-state installation, the maximum statistical environmental health risk would fall into an improved category. Identifying critical areas can provide exceptional control at the urban scale building that reduces the risks of natural radon. 

Ahmad Talebi

Papers

Investigation of Bacillus licheniformis in the biodegradation of Iranian heavy crude oil: A two-stage sequential approach containing factor-screening and optimization.

Enhanced biodegradation of light crude oil by immobilized Bacillus licheniformis in fabricated alginate beads through electrospray technique.

Improving mass transfer rates in microbial cell immobilization system for environmental applications: Synergistic interaction of cells on crude oil biodegradation.

Fuzzy radon hazard index assessment for stochastic environmental health risk evaluation of urban scale building