Oil Hydrocarbons Research Articles

A method for determining the environmentally safe residual content of oil and petroleum products in soils

Introduction. The Black Sea Coast of the Caucasus is one of the most important recreational and tourist regions for Russia. In recent years, it has been subjected to a sharply increased anthropogenic load, due to an increase in the number of tourists, accompanied by an increase in traffic flows and, as a result, an increase in environmental pollution, including oil hydrocarbons. The risks of leakage of oil products during transportation and pumping are increasing. To predict and prevent dangerous consequences of pollution, it is necessary to determine the environmentally safe residual content of oil and oil products in the soil, based on the regional ecological and geochemical characteristics of soils.
 Materials and methods. Laboratory modelling of contamination with oil and petroleum products (fuel oil, gasoline, diesel fuel) of sod-carbonate typical soil was carried out. To simulate pollution, oil and petroleum products were added to soil samples including fuel oil, gasoline, diesel fuel in a weight concentration of 1% (low pollution), 5% (medium pollution) and 10% (high pollution) of the soil mass. The exposure period lasted 30 days. After the specified period, changes in biological parameters (enzyme activity, radish root length, number of soil bacteria) were determined. Based on the listed parameters, the integral indicator of the biological state IIBS of the soil was calculated .
 Results. Oil and oil products pollution negatively affected the biological properties of the studied soil. A significant decrease in enzymatic activity, the number of bacteria, and the length of plant roots was recorded. The range of toxicity of the studied substances on biological indicators of soils is as follows: oil > fuel oil > gasoline > diesel fuel. The study made it possible to determine the maximum level of residual content of oil and petroleum products (fuel oil, gasoline, diesel fuel) in the refinery. For oil, it is 0.27%, for gasoline – 0.40%, for fuel oil – 0.30%, for diesel fuel – 0.45%.
 Limitations. The proposed limit levels of residual oil and petroleum products (fuel oil, gasoline, diesel fuel) in soils are applicable primarily on the territory of the Black Sea coast of the Caucasus.
 Conclusion. The proposed limit levels of the residual content of oil and petroleum products (fuel oil, gasoline, diesel fuel) in the soils of the refinery area can be used by environmental, agricultural and scientific organizations

Quantifying the roles of thermal volatilization and decomposition in microwave remediation of polycyclic aromatic hydrocarbon–polluted soil and modeling remediation effectiveness

Microwave irradiation is a promising technology for the remediation of soil contaminated by organic contaminants. However, the roles of volatilization and decomposition in microwave removal of polycyclic aromatic hydrocarbons (PAHs) in soil have not yet been quantitatively determined. A model describing the removal efficiency of benz(a)anthracene (BaA) at different treatment times and varied conditions was constructed, wherein BaA removal efficiency was positively and linearly correlated with soil temperature. BaA removal in soil was attributed to thermal volatilization (97.8%) and decomposition (2.2%). Radicals such as ∙OH and ∙O 2− were found to initiate BaA decomposition, the pathway of which was elucidated through HPLC-MS analysis, revealing benz(a)anthracene-7,12-dione as the main intermediate product. The new ideas and perspectives founded in this study offer theoretical support for microwave remediation of organic compound–contaminated sites.

Effect of Wheat Residue-Derived Biochar on Naphthalene Adsorption in Loess Soil in Northwest China

Research on the environmental behavior of polycyclic aromatic hydrocarbons (PAHs) in soil is limited, particularly regarding the influence of biochar on naphthalene (NAP) adsorption on the loess soil of Northwest China. In this study, a batch equilibrium experiment was used to analyze the sorption kinetics, sorption isotherms, and influencing factors of NAP adsorption by biochar derived from wheat residue at various pyrolysis temperatures on loess soil. The results indicated that NAP adsorption onto biochar-modified soil was rapid, within 6 h, and reached equilibrium after 20 h. The sorption kinetics was accurately described by a pseudo-second-order model. Additionally, the sorption isotherms were best described by the Freundlich model, indicating a multilayer adsorption mechanism. The average value of KF decreased as follows: BC-600 (2.03) > BC-400 (1.52) > BC-200 (1.25) > soil (0.91), indicating that biochar addition was beneficial for the adsorption of NAP on loess soil. The Gibbs free energy (ΔGθ) of NAP was less than zero, and the enthalpy (ΔHθ) and entropy (ΔSθ) values were greater than zero, suggesting that the adsorption occurred spontaneously through an endothermic reaction. Furthermore, the initial concentration of NAP influenced its adsorption amount. Pyrolysis temperatures of 400 °C and 600 °C resulted in higher NAP adsorption capacities, highlighting the beneficial effect of biochar addition on enhancing NAP adsorption in loess soil. However, at a pyrolysis temperature of 200 °C, the process of carbonization became incomplete, resulting in a reduction in the adsorption amount.

Proteomes reveal metabolic capabilities of Yarrowia lipolytica for biological upcycling of polyethylene into high-value chemicals.

Sustainable processes for biological upcycling of plastic wastes in a circular bioeconomy are needed to promote decarbonization and reduce environmental pollution due to increased plastic consumption, incineration, and landfill storage. Strain characterization and proteomic analysis revealed the robust metabolic capabilities of Yarrowia lipolytica to upcycle polyethylene into high-value chemicals. Significant proteome reallocation toward energy and lipid metabolisms was required for robust growth on hydrocarbons with n-hexadecane as the preferential substrate. However, an apparent over-investment in these same categories to utilize complex depolymerized plastic (DP) oil came at the expense of protein biosynthesis, limiting cell growth. Taken together, this study elucidates how Y. lipolytica activates its metabolism to utilize DP oil and establishes Y. lipolytica as a promising host for the upcycling of plastic wastes.

Study on co-slurry and co-combustion characteristics of coal and modified-coal gasification fine slag

In this study, hydrocarbon oil was used to modify coal gasification fine slag(CGFS) to improve its hydrophobic performance. The modified CGFS(MCGFS) was then mixed with coal to prepare MCGFS-coal water slurry(MCGFS-CWS), and the slurry’s flowability and combustion characteristics of MCGFS-CWS were investigated. XPS analysis and contact angle experiments revealed an increase in the non-polar groups on the surface of MCGFS, resulting in enhanced hydrophobicity with higher hydrocarbon oil content. The viscosity of MCGFS-CWS decreases as the amount of hydrocarbon oil increased, significantly improving its fluidity compared to CGFS-CWS. Under the conditions of this study, when the amount of hydrocarbon oil is 8%, the constant-viscosity concentration of MCGFS-CWS is 0.46% higher than that of CWS. Combustion characteristic studies revealed that the addition of CGFS increased the concentrations of alkali metals and alkaline earth metals in the slurry, promoting the catalytic combustion reaction. When the amount of hydrocarbon oil is large, the hydrocarbon oil in MCGFS ignites and burns at a lower temperature. The temperature released during the combustion of hydrocarbon oil is beneficial to promote the ignition of slurry and reduce the ignition temperature of MCGFS-CWS. These results demonstrate that hydrocarbon oil modification enhances the hydrophobicity of CGFS and reduces the ignition temperature of MCGFS-CWS.

Sepiolite promotes photodegradation of pyrene under visible light

Mechanochemistry and photocatalysis are emergent technologies for the remediation of polycyclic aromatic hydrocarbons (PAHs) in soils. In this work, mechanochemistry and photocatalysis are combined for pyrene degradation. The photodegradation of pyrene, when in contact with sepiolite under pressure application, is studied. The mechanical treatment leads to a pyrene crystal phase transformation. In this new phase, pyrene undergoes a fast photodegradation in the 320–420 nm range. We show that sepiolite is superior as a photocatalyst in pyrene degradation to TiO2, the most exploited photocatalyst. A broad physicochemical characterization is carried out to propose a mechanism in which the photoexcitation of mechanically altered pyrene leads to an electron transfer to sepiolite matrix, which triggers the PAH degradation. Finally, we want to highlight that the pyrene/sepiolite combination is a simplified system to shed light on how PAH photodegradation may occur in soils.

Radicals in West Absheron oil

Fractions of I-IV groups of aromatic hydrocarbons (AH) of West Absheron oil were studied by EPR and UV spectroscopy. Paramagnetism was not detected in the I group of AU. The presence of homologues of benzene, naphthalene, phenanthrene and anthracene was found in AC groups I-III. In oil fractions 120–230 oC, 150–280 oC EPR spectra are recorded ∆Hwidth=7.5 mT, g=2.3. Mn+2 were found in small amounts. In oil fractions 140–350 oC, 180–350 oC EPR signals were found ∆Hwidth=1.1 mT, g=2.002, which are also recorded in group II AC. Co, Mn+2 were also found in this group. In AC group IV, Co and asphaltene radicals are observed.

Spatial distribution and risk assessment of polycyclic aromatic hydrocarbons in soils from contaminated sites in Eastern China.

A total of 16 polycyclic aromatic hydrocarbons (PAHs) were measured in 28 soil column samples from two contaminated industrial sites in Eastern China. The total concentration of 16 PAHs (∑PAHs) in the surface soil (0-20cm) was measured up to 52,600ng/g (dry weight basis) with a remarkable spatial difference in the studied contaminated sites. The concentrations of the ∑PAHs in soils decreased with the increase in soil depth (0-10m). The surface and subsurface soil presented a tenfold higher concentration than the soil with depth greater than 4m. Additionally, the vertical migration tendency of the PAHs was found to be correlated significantly with their hydrophobicity (R2 = 0.79, P < 0.01). Naphthalene (with lowest octanol-water partition coefficient among the studied PAHs) showed the greatest average soil depth at which its peak concentration occurred. Furthermore, risk quotient analysis by using benzo[a]pyrene as reference compound showed that 71.4% of the samples exhibited high ecological risk for soil. Moreover, the total carcinogenic risk of the PAHs in the surface soil samples was assessed at 5.61 × 10-5-1.28 × 10-4 and 4.41 × 10-6-9.43 × 10-5 for male and female workers, respectively, in which 67.9%-71.4% of the samples showed potential risk. Generally, these results suggest a further consideration of ecological and health risks associated with PAHs in contaminated sites in Eastern China.

Application of whole-cell bioreporters for ecological risk assessment and bioremediation potential evaluation after a benzene exceedance accident in groundwater in Lanzhou, China

Oil spill events challenge human health and ecosystem safety, which are priority concerned issues for sustainable development. There is then an increasing demand of tools for ecological risks assessment at contaminated sites. In this study, we introduced two whole-cell bioreporters, ADPWH_alk and ADPWH_recA, to measure the available n-alkanes and the genotoxicities of total petroleum hydrocarbons in soils and groundwater which were contaminated by the Benzene Exceedance Accident in Lanzhou, China. Comparing to traditional chemical analysis methods, the whole-cell bioreporter method could provide risk assessment on cell level within a shorter time and a less cost, which is economical and environment friendly. The highest contents of available alkanes in soil and groundwater were 18,737 mg/kg and 308.4 mg/L, respectively. In addition, the available n-alkanes significantly (p < 0.01) correlated to chemical analysis of total n-alkanes. The highest genotoxicity level was found in soil and groundwater samples with lower TPHs concentration (4338.0 mg/kg and 1.4 mg/L Mitomycin C equivalent), suggesting the significant impacts of geochemical variables and alkane availability on the ecological risks of petroleum contamination. Combining chemical analysis and whole-cell bioreporter results, bioremediation strategies were suggested for groundwater and soils with higher n-alkane availability and lower ecological risks, whereas chemical oxidation were suggested for other contaminated sites. For the first time, we mapped the distribution of available n-alkanes and petroleum toxicities in a large scale soil-groundwater system using whole-cell bioreporters, showing their huge potential for rapid contaminant detection and fast risk assessment.

The impact of biochar-entrapped microorganisms on enzymatic activity and the cleanup of petroleum hydrocarbons in polluted soil

The impact of biochar-entrapped microorganisms on enzymatic activity and the cleanup of petroleum hydrocarbons in polluted soil

Evaluation of the content and degradation rates of PAHs in biochars, in terms of assessing the environmental risks of their application for soil remediation

The growing worldwide practice of biochar application as soil ameliorants, as well as adsorbents for remediation of soil contaminated with oil products and heavy metals, can lead to an increase the risk of environmental pollution by pyrolysis by-products. One of the most dangerous components of biochars is polycyclic aromatic hydrocarbons (PAHs), which are inevitably formed during the production of pyrogenic material. In this work, biochars obtained from various plant materials (millet, corn, willow, linden) under different pyrolysis temperatures were tested for the content of polycyclic aromatic hydrocarbons. The total content of PAHs in the studied samples ranged from 8.49 to 221.21 µg/kg, which does not exceed the limit concentrations established by the International Biochar Initiative. At the same time, polynuclear hydrocarbons with high carcinogenic and immunotoxic properties are found in the composition of biochars. A natural question arises about the effect of the final pyrolysis temperature on the total content and composition of PAHs in pyrolysis by-products. To study the degradation of polycyclic aromatic hydrocarbons in soil, linden biochar obtained by pyrolysis at 250 °C was used, from which the contaminants were extracted and applied to the soil so that the concentration of the marker was 20 and 40 µg/kg. The determination of the residual amount of polycyclic aromatic hydrocarbons was carried out after 1, 2, 6, and 11 months of incubation. Complete degradation of some 3–5-membered polycyclic aromatic hydrocarbons was found after 1–2 months of incubation. The most persistent pollutants were benzo(a)pyrene, benzo(b)fluoranthene, and pyrene, the concentration of which decreased to 31–71% on after 11 months of incubation. The slower degradation was found in the variant of the experiment with the high concentration level of polycyclic aromatic hydrocarbons. It was concluded that in soils selective accumulation of polynuclear PAHs, that most resistant to biodegradation, can occur.

In‐situ remediation of TPH‐polluted soil by Na2FeO4 in the Loess Plateau of China

AbstractIn recent years, the oil pollution problem on the Loess Plateau in western China is becoming increasingly serious, therefore, the use of hydroxyl radical (·OH) advanced oxidation process has increased due to its ability to efficiently degrade total petroleum hydrocarbon (TPH) in soil. However, the ability to produce ·OH of different oxidants varies widely, and the removal effect of specific pollutants has fluctuations and differences. The objective of this study is to screen the best oxidant according to the physico‐chemical properties and pollution situation of polluted soil, and to reveal the degradation mechanism of pollutants. In this study, we employed sodium ferrate (Na2FeO4) to produce ·OH for the degradation of TPHs in aged oil‐polluted soil located in the western part of the Loess Plateau in China. The results showed that the removal rates of TPH in the soil samples by hydrogen peroxide (H2O2), sodium persulfate (Na2SO4) and Na2FeO4 could reach 45.5%, 62.4%, and 65.6% respectively. The ·OH produced during the process played a major role in TPH oxidation with a contribution of more than 80%; H2O2 was intermediate substance that generated ·OH, biochar could induce the production of ·OH, the addition of biochar could activate H2O2 to promote the generation of ·OH and the removal rate is significantly increased by 19.2%. In situ remediation of polluted soil on the Loess Plateau using Na2FeO4, with a TPH degradation rate of 87.5%. The results of this study will provide a new method for the efficient degradation of TPH in loessial soil.

Hydrocarbon charging process of Ordovician strike‐slip fault zones in the Shunbei area, Tarim Basin, NW China

Ultra‐deep marine carbonate reservoirs is an important field for oil and gas exploration, and it is also a hot research topic in recent years. However, their hydrocarbon episodic charging model is still under debate up to now. A great breakthrough has been made in the newly discovered ultra‐deep fault‐karst oil reservoir in the Shunbei area of Tarim Basin. Based on quantitative gas chromatogram‐mass spectrometry, stable carbon isotopes of reservoir oils, microthermometry and confocal laser scanning analyses of fluid inclusions, the reservoir oil origin and hydrocarbon charging history in Shunbei No. 1, No. 5 and No. 7 strike‐slip fault zones are expounded. The results showed that the Ordovician reservoir oil derives from the source rocks within the Cambrian Yuertusi Formation deposited in a highly anoxic bottom water environment. There were four stages of hydrocarbon charging in the study area, in the late Caledonian, late Hercynian–Indosinian, middle Yanshanian and late Himalayan. During this period, the force‐field strength of the charged oil gradually decreased, and the early‐stage charged crude oil with low maturity and high force‐field strength preferentially accumulated in the Yijianfang Formation, while the late‐stage charged crude oil with high maturity and low force‐field strength preferentially accumulated in the Yingshan Formation. This study reveals the history and differences of petroleum accumulation in the Shunbei fault zones, which is significance for understanding the hydrocarbon distribution in ultra‐deep marine carbonate reservoirs.

Potential for natural attenuation of crude oil hydrocarbons in benthic microbiomes near coastal communities in Kivalliq, Nunavut, Canada

Oil spilled in marine environments can settle to the seafloor through aggregation and sedimentation processes. This has been predicted to be especially relevant in the Arctic due to plankton blooms initiated by melting sea ice. These conditions exist in the Kivalliq region in Nunavut, Canada, where elevated shipping traffic has increased the risk of accidental spills. Experimental microcosms combining surface sediment and crude oil were incubated at 4 °C over 21 weeks to evaluate the biodegradation potential of seabed microbiomes. Sediments sampled near the communities of Arviat and Chesterfield Inlet were assessed for biodegradation capabilities by combining hydrocarbon geochemistry with 16S rRNA gene and metagenomic sequencing, revealing decreased microbial diversity but enrichment of oil-degrading taxa. Alkane and aromatic hydrocarbon losses corresponded to detection of genes and genomes that encode enzymes for aerobic biodegradation of these compounds, pointing to the utility of marine microbiome surveys for predicting the fate of oil released into Arctic marine environments.

Artificial Olfactory System for Distinguishing Oil-Contaminated Soils

Oil-contaminated soils are a major environmental problem for Kazakhstan. Oil spills or leaks lead to profound changes in the physical and agrochemical properties of the soil and the accumulation of hazardous substances. Whilst there are many remote sensing techniques and complex laboratory methods for oil spill detection, developing simple, reliable, and inexpensive tools for detecting the presence of pollutants in the soil is a relevant research task. The study aims to research the possibilities of an electronic nose combining a chemical sensor array with pattern recognition techniques to distinguish volatile organic compounds from several types of hydrocarbon soil pollutants. An electronic nose system was assembled in our laboratory. It includes eight gas metal oxide sensors, a humidity and temperature sensor, an analog-digital processing unit, and a data communication unit. We measured changes in the electrical conductivity of sensors in the presence of volatile organic compounds released from oil and petroleum products and samples of contaminated and uncontaminated soils. The list of experimental samples includes six types of soils corresponding to different soil zones of Kazakhstan, crude oil from three oil fields in Kazakhstan, and five types of locally produced fuel oil (including gasoline, kerosene, diesel fuel, engine oil, and used engine oil). We used principal component analysis to statistically process multidimensional sensor data, feature extraction, and collect the volatile fingerprint dataset. Pattern recognition using machine learning algorithms made it possible to classify digital fingerprints of samples with an average accuracy of about 92%. The study results show that electronic nose sensors are sensitive to soil hydrocarbon content. The proposed approach based on machine olfaction is a fast, accurate, and inexpensive method for detecting oil spills and leaks, and it can complement remote sensing methods based on computer vision.

Оценка экологического состояния реки Сояна в зоне возможного воздействия алмазоносного месторождения

The article presents the results of a comprehensive study of the Soyana River for the first time. The characteristics of hydrological and hydrochemical parameters were obtained while observations in July 2020 and March 2021. Changes in the hydrogen index (pH), mineralization, and the content of dissolved oxygen and biogenic elements in water, as well as petroleum hydrocarbons in water and bottom sediments were studied using generally accepted in hydrochemical practice methods. The data obtained were evaluated for compliance with the regulatory requirements for the river water quality. According to the chemical composition, the Soyana River water belongs to the hydrocarbonate class of small and medium mineralization (164–296 mg/L), weakly acidic and slightly alkaline type (pH 6.0–8.2). The data obtained allow us to conclude that there is no noticeable anthropogenic impact on the considered watercourse. The petroleum hydrocarbons content in water and bottom sediments was below maximum permissible concentrations. In river water it was below 0.010 mg/L, in bottom sediments – in the range from 0.2 to 3.2 mg/kg. The maximum content of petroleum hydrocarbons in soils was recorded in the lower course of the river, where bottom sediments are presented in the form of silty sand. The interannual variability of hydrological and hydrochemical characteristics in the direction from the source to the mouth of the river is estimated. The relationship and regularity of their distribution was specified. The data obtained can serve as background data for assessing the negative impact in case of anthropogenic load on the river basin.

Source apportionment and source specific health risk assessment of HMs and PAHs in soils with an integrated framework in a typical cold agricultural region in China

A new innovative methodology system framework for source apportionment and source-specific risk assessment has been proposed and actively applied to identify the contamination characteristics, oriented sources and health risks associated with contamination levels of Heavy metals (HMs) and Polycyclic Aromatic Hydrocarbons (PAHs) in soils, a typical cold agricultural region in Northeastern China. To achieve this meaningful goal, a large-scale dataset including 1780 top soil samples, 10 HMs and 16 priority PAHs has been organized and collected from a typical study area in China. The total concentrations of the 10 selected HMs in study area range from 0.05 to 2147.40 mg/kg, with an average of 549.25 ± 541.37 mg/kg. The average concentrations of PAHs for (3–6)-rings are 16.60 ± 18.90, 26.40 ± 28.20, 9.51 ± 13.00 and 1.99 ± 5.30 ng/g, respectively. On the base of optimized literature source fingerprints for HM and PAH, a widely used receptor model, positive matrix factorization (PMF) has been applied to apportion the contamination sources HMs and PAHs in soils. Then source-specific health risk of soil HMs and PAHs have been assessed using the probabilistic incremental lifetime cancer risk model incorporated with source apportionment results data. Fertilizer residues/coke oven comprise the primary contamination source contributors of HMs and PAHs with corresponding contributions of 32.23 % and 27.93 % for HMs and 37.94 % for PAHs. Fertilizer/pesticide residues contributes most to the risks of soil HMs (28.8 %), followed by fossil fuel combustion (24.6 %), mining activities (20.2 %), traffic and vehicle emission (16.3 %) and electroplating/dyeing (14.1 %). Meanwhile, the ranking of health risks from the five identified contamination sources of soil PAHs are resident discharge, coal-fired boilers, coke oven emission, gasoline combustion and power plant, with the contribution of 27.1 %, 25.3 %, 17.3 %, 15.5 % and 14.8 %.And relatively, source-specific risk assessment demonstrates fossil fuel and coal combustion contribute the greatest impact to the total risk of HMs and PAHs (61.7 % and 56.1 %), respectively. This study provides a good example of how the source specific health risk assessment can be utilized to reduce the contamination in soils.

Pd nanoparticles lubricant additive catalyze the construction of carbon-based tribofilm to reduce graphitization-induced wear of DLC films under boundary lubrication

To explore approaches of reducing graphitization-induced wear on the friction surface of DLC films under boundary lubrication to increase their service life, Pd nanoparticles (PdNPs) prepared by chemical reduction method were used as lubricant additive of DLC films and GCr15 ball under boundary lubrication. Tribotests, reactive force field molecular dynamics (ReaxFF MD) and surface characterization methods, such as SEM, XPS, Raman and FIB-TEM, were used to study the effects of PdNPs as lubricant additive on the graphitization-induced wear of DLC films and the effect mechanisms. The results show that, PdNPs lubricant additive can reduce the friction coefficient (COF) of the tribosystems, and more importantly, they can obviously increase the lifespan of DLC films. Characterization results indicate that PdNPs can promote the tribochemical reaction on the friction surface and catalyze the formation of carbon-based tribofilm on the friction surface, which significantly reduces the graphitization-induced wear of DLC films. ReaxFF MD studies show that PdNPs effectively catalyze the massive dehydrogenation and chain-breaking of base oil hydrocarbon molecules, providing the basis for the formation of carbon-based tribofilm. These results indicate that PdNPs are promising as effective additive to prolong the service life of DLC films under boundary lubrication.

Screening of Bacteria Isolated from Arctic Atmospheric Aerosols for Oil Degradation Ability

Currently, a significant part of the world's soil cover is exposed to negative pollution, leading to its degradation. Oil hydrocarbons play a significant role among numerous soil pollutants. Sources of pollution are enterprises of oil extraction, oil refining, oil and oil products transportation. Every year in the world millions of tons of oil and oil products are lost during extraction, transportation, storage and use. Biological remediation based on the potential of microorganisms to transform pollutants of different origin is the most promising and environmentally safe method of restoring soil fertility, so the search for new strains to create and improve such biological preparations is still relevant. Atmospheric aerosols are a source of both transient and endogenous microbiota, which are metabolically active in relation to pollutants. During a complex airborne expedition on atmospheric sounding over the Arctic Ocean seas samples of aerosols were collected for microbiological analysis. The isolated cultures of microorganisms belonging to the genera Bacillus, Acinetobacter, Rhodococcus were tested for the ability to oil destruction when growing on agarized and liquid medium with the addition of oil to 2% as the only source of carbon and incubation for 10 days. The bioemulsifying and biodegrading abilities of microorganisms during growth in liquid medium were estimated visually by destruction of the surface film of oil, turbidity of the nutrient medium due to an increase in the biomass of microorganisms, formation of a uniform emulsion of oil in the medium, microscopy of cultural suspensions, and by their seeding on agarized nutrient medium to determine the titer of viable cells. Highly effective mesophilic and psychrotolerant oil destructor bacteria were isolated from northern atmospheric aerosols, which can be used to create complex biopreparations capable of assimilating a wider range of oil hydrocarbons for remediation of polluted soils and grounds in cold territories of Siberia and the Arctic.

Downwind gas condensate volatiles affect phytoplankton communities

We investigated the effects of volatile organic carbons (VOCs) evaporated from gas condensate on the cyanobacteria Synechococcus sp. WH8103, the diatom Asterionellopsis glacialis, and the dinoflagellate Alexandrium minutum. We used custom algal incubation chambers enabling only the gas condensate-derived VOCs to interact with the cell cultures via an atmospheric bridge, without direct contact with the hydrocarbon oil. The exposure to gas condensate VOCs reduced the abundance, growth rate, and photosynthetic efficiency of Synechococcus sp. WH8103. Thiobarbituric acid reactive substances (TBARS) assays hint at oxidative damage to the chloroplasts and/or the thylakoid membranes in this organism. A.glacialis abundance, physiological state and growth rates remained unchanged, whereas A.minutum abundance and photosynthetic efficiency increased relative to their respective controls. Our results demonstrate that the effects of a gas condensate formed due to an oil spill will not be restricted to the polluted area, but may be prominent in downwind locations through atmospheric transport.