Oil Spills in the Niger Delta Region, Nigeria: Environmental Fate of Toxic Volatile Organics.

Background: Over the years, the issue of environmental degradation of ecological resources from crude oil pollution and its human health impacts is receiving more global attention. The utilization of environmental models capable of predicting the fate, transport and toxicity of chemicals in spilled crude oil can provide essential knowledge required to deal with the complexity associated with the fate of volatile petroleum chemicals in the environment. Objective: This paper explores environmental fate of toxic volatile organics from oil spill in the Niger Delta Region of Nigeria.Methods: A critical analysis of available literatures/data from PubMed, Scopus, ResearchGate, Google Scholar, Jstor, including expert working group reports and environmental modeling using a screening tool (USEPA EPI Suite™) was carried out to determine the environmental partitioning of Benzene, Toluene and Naphthalene (BTN) respectively. The organic-carbon partitioning coefficient (Koc) was computed as a function of soil-water distribution coefficient (Kd) and percentage organic matter (%OM). This was utilized to determine the distribution of BTN in the environment and the possible risk posed on delicate ecological resources from crude oil pollution due to exploration and production activities within the Niger Delta Region (NDR), Nigeria. Results: Results from literature implicated sabotage and operational failures from pipelines as primary causes of crude oil spillages. Generation of a fugacity model using EPI Suite™ revealed that the behavior of BTN is greatly influenced by Koc values. The default Molecular Connectivity Index (MCI) showed that benzene and toluene will partition more into the water compartment while naphthalene will partition into the soil compartment. However, user-entered values showed all three chemicals partitioning more into the soil compartment. Aquatic toxicology estimation using Ecological Structural Activity Relationship (ECOSAR) revealed all chemicals not to be toxic even at over-estimated Koc values. Conclusion: This research established the usefulness of screening level environmental modelling tools in assessing environmental risk and hence helpful in developing site-specific models for monitoring chemicals in the environment which can assist governments, policy makers and industries in the design of appropriate regional disaster management plans.

Changes of Heart Rate and Lipid Composition in Mytilus Edulis and Modiolus Modiolus Caused by Crude Oil Pollution and Low Salinity Effects

Blue mussels, Mytilus edulis, inhabiting tidal zones, are naturally exposed to fluctuating environmental conditions (e.g., fluctuations in temperature and salinities), while horse mussels, Modiolus modiolus, live under relatively invariable shelf water conditions. The present investigation tested the hypothesis: blue mussels, in comparison to horse mussels, have an increased ability to tolerate the stress of pollution combined with low salinity. To assess the response of blue mussels and horse mussels to oil pollution at seawater salinities of 25 psu (normal) and 15 psu (low), we used a combination of heart rate and lipid composition as physiological and biochemical indicators, respectively. A sharp decrease in heart rate as well as important fluctuations in cardiac activity was observed under all oil concentrations. Modifications in the concentrations of the main membrane lipid classes (phosphatidylcholine, phosphatidylethanolamine, and cholesterol) and storage lipids (primarily triacylglycerols) in response to different crude oil concentrations were time- and dose-dependent. Both chosen indicators showed a high sensitivity to crude oil contamination. Furthermore, both bivalve species showed similar responses to oil pollution, suggesting a universal mechanism for biochemical adaptation to crude oil pollution.

Variations of Structural and Functional Traits of Azolla pinnata R. Br. in Response to Crude Oil Pollution in Arid Regions

In oil-producing countries, water pollution by crude petroleum oil frequently occurs and causes many environmental problems. This study aims to investigate the effect of crude petroleum oil on the growth and functional trails of the economically important freshwater plant Azolla pinnata R. Br. and to report on the plant’s resistance to this abiotic stress. Plants were raised in an open greenhouse experiment under different levels of crude oil pollution ranging from 0.5 to 2.0 g/L. Plant functional traits were monitored over a three-week period. Plant cover of A. pinnata was decreased with the increased levels of oil pollution. The total chlorophyll content decreased from 0.76 mg/g fresh weight under 2 g/L oil treatment after 21 days of growth. The chlorophyll a/b ratio exceeded the unity at crude oil treatments above 1 g/L, with values reaching 2.78 after seven days, while after 21 days, the ratio ranged from 1.14 to 1.31. The carotenoid content ranged from 0.17 mg/g in the control to 0.11 mg/g in the 2 g/L oil treatment. The carotenoid content varied over time in relation to DNA% damage, which increased from 3.63% in the control to 11.36% in the highest oil treatment level of 2 g/L. The crude oil stress caused severe damage in the frond tissues and chloroplast structure of A. pinnata, including a less compacted palisade, the malformation of the epidermis, the disintegration of parenchyma tissue, and the lysis and malformation of the chloroplasts. Since A. pinnata cannot withstand high concentrations of crude oil pollution, it is for use in the remediation of slightly polluted freshwaters up to 0.5 g/L.