A Review of the Petroleum Hydrocarbons Contamination of Soil, Water and Air and the Available Remediation Techniques, Taking into Consideration the Sustainable Development Goals

The emergence of several industrial activities has arguably led to hydrocarbon contamination of all aspects of the environment. The resultant effect of the increased dependence on crude oil is the hydrocarbon pollution via the exploration, transport and waste disposal. Crude oil is a complex mixture of aliphatic, aromatic and heterocyclic compounds. The impact of the crude oil spills, pesticides, fossil fuels and other organic pollutants, which majorly contains these hydrocarbons is that the natural heavy metal content of the soil is drastically rising, resulting in high concentration of heavy metals, thereby limiting the microbe’s activity, rendering it unsuitable for degradation and reduced effectiveness. This menace has hereby brought the dire need for adequate environmental remediation technique, putting into consideration the achievement of the Sustainable Development Goals (SDGs’). Variety of techniques exist for remediation depending on the media (e.g. air, water, or soil) and contaminant (e.g. heavy metals, PCB etc.). Some of the techniques adopted in the last several decades are physical/mechanical, chemical or biochemical remediation methods.

Evaluation of the physico-chemical state of the soil contaminant isolate indigenous bacterial species

The aim of the study is to isolate indigenous bacterial species which have the ability to degrade crude oil. Samples were collected from an oil polluted site in Ejama-Ebubu Eleme Rivers state. The samples were taken from five spot (A-E), of depth 0-15 (A1– E1) and 15-30 (A2– E2) in sterile polyethylene bags, using appropriate equipment, then taken to the laboratory for analysis, Physicochemical parameters such as pH, nitrate, sulphate, phosphate, total petroleum hydrocarbon (TPH), poly aromatic hydrocarbon (PAH), salinity, temperature, conductivity and heavy metals (iron, zinc, nikel, lead, chromium) were determined, The THB count was determined using the spread plate method on nutrient agar. Soil, sediment and water physicochemical parameters determined indicated that the samples had been exposed to hydrocarbon contamination. The Gram negative bacteria belonging to the genus pseudomonas is the most frequent. Other genera isolated were Nocardia, Micrococcus,Chromobacterium, Burkholdia, Corynebacterium. The study revealed the presence of petroleum hydrocarbons in the Ejama_Ebubu site as well as known genera of hydrocarbon utilizing bacteria. The biases associated with culture-dependent microbial enumeration techniques may limit the full description of the bacterial diversity in Ejama-Ebubu site. From the study, it is concluded that microorganisms that can degrade hydrocarbons are found in oil contaminated soil and can easily be isolated from these contaminated sites, although it is very difficult to work with aromatic hydrocarbons due to their volatility and toxic effects.

Atmospheric Photoionization Detector with Improved Photon Efficiency: A Proof of Concept for Application of a Nanolayer Thin-Film Electrode

Atmospheric photoionization is a widely applied soft ionization mechanism in gas sensing devices for the detection of volatile organic compounds in ambient air. Photoionization is typically induced by low-pressure Vacuum Ultraviolet (VUV) lamps with MgF2 or LiF lamp surface windows depending on the gas fill and the required wavelength transmission window. These lamps are known to exhibit gradually reduced VUV transmission due to hydrocarbon contamination. LiF surface windows are known to be especially problematic due to their hygroscopic nature, reducing VUV lamp lifetime to a mere 100 h, approximately. Here, we present a new design for the electrode of a photoionization detector based on thin-film technology. By replacing the commonplace metal grid electrode’s VUV lamp surface window with a chromium/gold thin film we obtain a doubling of photon efficiency for photoionization. Replacing the hygroscopic LiF lamp window surface with a metallic layer additionally offers the possibility to vastly increase operational lifetime of low-pressure Argon VUV lamps.

Effect of Soil Contamination with Crude Petroleum on Cowpea: An Insight into the Prospects of Crop Production in Nigerian Frontier Basins

Petroleum hydrocarbon contamination remains a major challenge confronting soil health, environmental sustainability, and food security in oil exploration areas. In this study, the effect of Bonny Light crude oil on cowpea (Vigna unguiculata L. Walp.) was investigated with a view to assessing its toxicity to plant growth and performance. Pristine soil samples were collected in different pots and contaminated with crude oil to achieve 0.0%, 2.5%, 5.0%, 7.5% and 10.0% v/w contamination levels. Viable seeds of cowpea were planted and monitored for the emergence and subsequent growth for a period of 12 weeks. Results showed that the crude oil extended the period of seed germination and delayed the emergence of sprouts by 2 days at a rate of 96.7%, 80.0%, 50.0%, 96.7%, and 73.3% emergence respectively. The plants’ shoots, roots, and leaves lengths were longer in control than in the contaminated soil. Phytotoxicity study showed that shoots, roots and leaves lengths of the plants were significantly reduced by ≥ 50% of the control. The relative plants' weights, chlorophyll, and the number of leaves were worst affected especially in plants grown in higher crude oil concentrations where fewer or absence of leaves was observed at the end of the experiments. No yield parameter was observed in all plants grown in contaminated soil as opposed to the control where flowers, fruits, and seeds were produced. The findings illustrated that the growth rate of V. unguiculata was severely affected due to hydrocarbon contamination in a concentration-dependent manner. It further demonstrated the imminent danger to food security especially in frontier basins with impending oil exploration activities. Therefore, there is a need to identify and integrate effective measures that minimize or prevent oil spillage in the course of oil exploration activities with a view to avoiding the repeat of persistent pollution problems disturbing host communities.

Occurrence of Mineral Oil Hydrocarbons in Omega-3 Fatty Acid Dietary Supplements

Omega-3 fatty acid dietary supplements have become increasingly popular with consumers due to their multiple health benefits. In this study, the presence of mineral oil hydrocarbons (MOH) was investigated in seventeen commercial samples of such supplements, characterized by different formulations. The analyses were performed using on-line liquid chromatography–gas chromatography (with flame ionization detection), which is considered the most efficient method for the determination of MOH in foodstuffs. Analyte transfer was performed by using the retention gap technique, with partially concurrent solvent evaporation. Various degrees of mineral oil saturated hydrocarbon contamination (from 2.4 ppm to 375.7 ppm) were found, with an average value of 49.9 ppm. Different C-number range contaminations were determined, with the >C25–≤C35 range always found with an average value of 26.9 ppm. All samples resulted free of mineral oil aromatic hydrocarbons, except for two samples in which a contamination was found at the 9.9 and 6.6 ppm levels, respectively.

Assessment of Mycoremediation Potential of Fusarium Spp. On Polycyclic Aromatic Hydrocarbon in Western India

Motor or engine oil is a lubricant for engines containing majorly of base oils; these base oils include petrol-based hydrocarbons. Petroleum hydrocarbon contamination is one of the major environmental problems resulting from its large scale uses in transportation, industrial and other sectors. Accidental release and workshop seepage of petroleum products are the key concern of the environment. Fresh engine oil contains polycyclic aromatic hydrocarbons (PAHs). Used engine oil also leads to further generation of PAHs. As an attempt to clean up such hydrocarbons, bioremediation or biodegradation methods are adapted. Bioremediation is a cost effective and eco-friendly treatment for oil contaminated materials by the use of micro-organisms. The present study is an attempt to isolate and find out hydrocarbon degrading fungi from oil and petroleum contaminated regions. Biodegradation potential of soil mycobiota isolated from automobile mechanic workshop in Virar on engine oil was investigated using standard methods. The most capable oil degrading fungi was identified morphologically by wet mount technique as Fusarium sp. The biodegradation of hydrocarbons and oil was determined by using 2,6 Dichlorophenol-indophenol (DCPIP) assay and gravimetric analysis. The quantitative estimation of engine oil degradation showed rate of degradation as 87% and 89%. This study confirms that isolated Fusarium sp. has the potential exploited in the bio-treatment and removal of hydrocarbons from the polluted soil. Results were recorded in the form of biodegradation percentage of hydrocarbon. The present study and their results can give unique future prospects in the field of bioremediation and biodegradation of petroleum contaminated soil.

Surfactant Enhanced Bioremediation of Hydrocarbon Contaminated Soils Using Alkyl Polyglucoside

Bioremediation is an efficient and environmentally friendly method for the degradation of petroleum hydrocarbons in contaminated soils. This study investigated the effects of biosurfactant alkyl polyglycosides (APG) on enhanced biodegradation of petroleum hydrocarbon contaminated soils. Three soil samples were contaminated with two different grades of crude oil (medium and Light). Alkyl polyglucoside was synthesised and subjected to FTIR for comfirmation of the product before it was applied in the remediation of contaminated soil. The alkyl polyglucoside is used as a treatment regime in the remediation of the hydrocarbon contamination in the three soil samples. Results of total petroleum hydrocarbons (TPH) before remediation with bio-surfactant showed that samples contaminated with medium crude for Eneka, Ozuoba and Rukpokwu were 15744.00 mg/kg, 11359.00 mg/kg and 11470.00 mg/kg respectively and after remediation reduced to 4276.00 mg/kg, 4265.00 mg/kg, and 3205.00 mg/kg, showing a reduction percentage of 72.84%, 62.44% and 72.05% respectively. Soil samples contaminated with light crude showed result of TPH of 11339.00 mg/kg, 10662 mg/kg and 10226 mg/kg and after remediation reduced to 2981 mg/kg, 3879 mg/kg, and 4245 mg/kg respectively showing a reduction percentage of 73.71%, 63.62 % and 58.49% respectively. The enhanced efficiency of the bio-surfactant at degrading total petroleum hydrocarbons was achieved as a result of the increased solubility thus improving the bioavailability of the hydrocarbons due to the action of the alkyl polyglucoside.

The Impact of Different Types of Hydrocarbon Disturbance on the Resiliency of Native Desert Vegetation in a War-Affected Area: A Case Study from the State of Kuwait

This study assesses the impact of total petroleum hydrocarbon (TPH) concentration and soil parameters (heavy metals, chemical properties, and water-soluble boron) on the succession process of vegetation survival in the Al-Burgan oil field in Kuwait. A total of 145 soil samples were randomly collected from the three main types of hydrocarbon contamination, including dry oil lake (DOL), wet oil lake (WOL), and tarcrete. Sampling was also extended to noncontaminated bare soils that were considered reference sites. Remote-sensing data from Sentinel-2 were also processed to assess the level of contamination in relation to soil surface cover. The results showed that TPH concentration was significantly higher in WOL and DOL (87,961.4 and 35,740.6 mg/kg, respectively) compared with that in tarcrete (24,063.3 mg/kg), leading to a significant increase in soil minerals and heavy metals, greater than 50 mg/kg for Ba, and 10 mg/kg for V, Zn, Ni, and Cr. Such high concentrations of heavy metals massively affected the native vegetation’s resiliency at these sites (<5% vegetation cover). However, vegetation cover was significantly higher (60%) at tarcrete-contaminated sites, as TPH concentration was lower, almost similar to that in uncontaminated areas, especially at subsurface soil layers. The presence of vegetation at tarcrete locations was also associated with the lower concentration of Ba, V, Zn, Ni, and Cr. The growth of native vegetation was more likely related to the low concentration of TPH contamination at the subsurface layer of the soils in tarcrete sites, making them more suitable sites for restoration and revegetation planning. We concluded that further investigations are required to provide greater insight into the native plants’ phytoextraction potential and phytoremediation.