Biological Responses of Pacific Herring Embryos to Crude Oil Are Quantifiable at Exposure Levels Below Conventional Limits of Quantitation for PAHs in Water and Tissues.

Pacific herring (Clupea pallasii), a cornerstone of marine food webs, generally spawn on marine macroalgae in shallow nearshore areas that are disproportionately at risk from oil spills. Herring embryos are also highly susceptible to toxicity from chemicals leaching from oil stranded in intertidal and subtidal zones. The water-soluble components of crude oil trigger an adverse outcome pathway that involves disruption of the physiological functions of cardiomyocytes in the embryonic herring heart. In previous studies, impaired ionoregulation (calcium and potassium cycling) in response to specific polycyclic aromatic hydrocarbons (PAHs) corresponds to lethal embryolarval heart failure or subtle chamber malformations at the high and low ends of the PAH exposure range, respectively. Sublethal cardiotoxicity, which involves an abnormal outgrowth (ballooning) of the cardiac ventricular chamber soon after hatching, subsequently compromises juvenile heart structure and function, leading to pathological hypertrophy of the ventricle and reduced individual fitness, measured as cardiorespiratory performance. Previous studies have not established a threshold for these sublethal and delayed-in-time effects, even with total (∑)PAH exposures as low as 29 ng/g of wet weight (tissue dose). Here, we extend these earlier findings showing that (1) cyp1a gene expression provides an oil exposure metric that is more sensitive than typical quantitation of PAHs via GC-MS and (2) heart morphometrics in herring embryos provide a similarly sensitive measure of toxic response. Early life stage injury to herring (impaired heart development) thus occurs below the quantitation limits for PAHs in both water and embryonic tissues as a conventional basis for assessing oil-induced losses to coastal marine ecosystems.

Metagenome meta-analysis reveals an increase in the abundance of some multidrug efflux pumps and mobile genetic elements in chemically polluted environments.

Many human activities contaminate terrestrial and aquatic environments with numerous chemical pollutants that not only directly alter the environment but also affect microbial communities in ways that are potentially concerning to human health, such as selecting for the spread of antibiotic-resistance genes (ARGs) through horizontal gene transfer. In the present study, metagenomes available in the public domain from polluted (with antibiotics, with petroleum, with metal mining, or with coal-mining effluents) and unpolluted terrestrial and aquatic environments were compared to examine whether pollution has influenced the abundance and composition of ARGs and mobile elements, with specific focus on IS26 and class 1 integrons (intI1). When aggregated together, polluted environments had a greater relative abundance of ARGs than unpolluted environments and a greater relative abundance of IS26 and intI1. In general, chemical pollution, notably with petroleum, was associated with an increase in the prevalence of ARGs linked to multidrug efflux pumps. Included in the suite of efflux pumps were mexK, mexB, mexF, and mexW that are polyspecific and whose substrate ranges include multiple classes of critically important antibiotics. Also, in some instances, ß-lactam resistance (TEM181 and OXA-541) genes increased, and genes associated with rifampicin resistance (RNA polymerases subunits rpoB and rpoB2) decreased in relative abundance. This meta-analysis suggests that different types of chemical pollution can enrich populations that carry efflux pump systems associated with resistance to multiple classes of medically critical antibiotics.IMPORTANCEThe United Nations has identified chemical pollution as being one of the three greatest threats to environmental health, through which the evolution of antimicrobial resistance, a seminally important public health challenge, may be favored. While this is a very plausible outcome of continued chemical pollution, there is little evidence or research evaluating this risk. The objective of the present study was to examine existing metagenomes from chemically polluted environments and evaluate whether there is evidence that pollution increases the relative abundance of genes and mobile genetic elements that are associated with antibiotic resistance. The key finding is that for some types of pollution, particularly in environments exposed to petroleum, efflux pumps are enriched, and these efflux pumps can confer resistance to multiple classes of medically important antibiotics that are typically associated with Pseudomonas spp. or other Gram-negative bacteria. This finding makes clear the need for more investigation on the impact of chemical pollution on the environmental reservoir of ARGs and their association with mobile genetic elements that can contribute to horizontal gene transfer events.

Genomic and biotechnological potential of a novel oil-degrading strain Enterobacter kobei DH7 isolated from petroleum-contaminated soil.

In this study, a novel oil-degrading strain Enterobacter kobei DH7 was isolated from petroleum-contaminated soil samples from the industrial park in Taolin Town, Lianyungang, China. The whole genome of the strain was sequenced and analyzed to reveal its genomic potential. The oil degradation and growth conditions including nitrogen, and phosphorus sources, degradation cycle, biological dosing, pH, and oil concentration were optimized to exploit its commercial application. The genome of the DH7 strain contains 4,705,032 bp with GC content of 54.95% and 4653 genes. The genome analysis revealed that there are several metabolic pathways and enzyme-encoding genes related to oil degradation in the DH7 genome, such as the paa gene cluster which is involved in the phenylacetic acid degradation pathway, and complete degradation pathways for fatty acid and benzoate, genes related to chlorinated alkanes and olefins degradation pathway including adhP, frmA, and adhE, etc. The strain DH7 under the optimized conditions has demonstrated a maximum degradation efficiency of 84.6% after 14 days of treatment using synthetic oil, which comparatively displays a higher oil degradation efficiency than any Enterobacter species known to date. To the best of our knowledge, this study presents the first-ever genomic studies related to the oil degradation potential of any Enterobacter species. As Enterobacter kobei DH7 has demonstrated significant oil degradation potential, it is one of the good candidates for application in the bioremediation of oil-contaminated environments.

Petroleum pollution changes microbial diversity and network complexity of soil profile in an oil refinery.

Introduction: Petroleum pollution resulting from spills and leakages in oil refinery areas has been a significant environmental concern for decades. Despite this, the effects of petroleum pollutants on soil microbial communities and their potential for pollutant biodegradation still required further investigation. Methods: In this study, we collected 75 soil samples from 0 to 5 m depths of 15 soil profiles in an abandoned refinery to analyze the effect of petroleum pollution on soil microbial diversity, community structure, and network co-occurrence patterns. Results: Our results suggested soil microbial a-diversity decreased under high C10-C40 levels, coupled with significant changes in the community structure of soil profiles. However, soil microbial network complexity increased with petroleum pollution levels, suggesting more complex microbial potential interactions. A module specific for methane and methyl oxidation was also found under high C10-C40 levels of the soil profile, indicating stronger methanotrophic and methylotrophic metabolic activities at the heavily polluted soil profile. Discussion: The increased network complexity observed may be due to more metabolic pathways and processes, as well as increased microbial interactions during these processes. These findings highlight the importance of considering both microbial diversity and network complexity in assessing the effects of petroleum pollution on soil ecosystems.

The effect of petroleum levels on some soil biological properties under phytoremediation and bioaugmentation.

With the development of industries and excessive use of petroleum compounds, petroleum pollution has become a serious threat to the environment. The aim of this study was to the effect of petroleum levels on the biological activities of soil affected by phytoremediation and bioaugmentation. A surface soil sample was collected from the polluted areas around Bandar Abbas Oil Refinery Company, and the petroleum-degrading bacteria were isolated. M. yunnanensis (native) was selected among the isolated colonies for further experiment. The used soil in this study was a surface soil collected from Baghu region of Bandar Abbas, Sothern Iran, and treatments were added to soil samples. To evaluate removal of petroleum levels (0, 4, and 8%) from the soil by phytoremediation (control, sorghum, barley, and bermudagrass) and bioaugmentation (control, A. brasilense (non-native) and M. yunnanensis) and bioaugmented phytoremediation, a factorial pot experiment with completely randomized design and three replications was performed. The results demonstrated that sorghum and bermudagrass were more resistant than barley to the toxic effects of petroleum. Positive effect of bacteria on dry weight in polluted soil was greater than in the non-polluted soil. The degradation of petroleum reaches 77% in sorghum + M. yunanesis + 4% petroleum. Plants had stronger ability to degrade total petroleum hydrocarbon (TPH), while bacteria could better degrade polyaromatic hydrocarbons (PAHs). Application of bacteria and plants stimulated soil biological characteristics (dehydrogenase, arylsulfatase, lipase, bacterial population, and respiration) in polluted soil. Among measured enzymes, dehydrogenase exhibited a stronger response to petroleum levels. Four-percent level had greater irritating effect on soil biological properties. Plants and bacteria rely on differences in biological properties to attain synergy in petroleum degradation. Results indicated that M. yunnanensis has a high ability to remove petroleum from soil, and plants enhance the efficiency of this bacterium.

Environmental risk assessment of petrogenic hydrocarbon spills in mangrove ecosystems: the Tumaco case study as a baseline, Colombian Pacific.

Petrogenic hydrocarbon spills (PHS) are harmful to mangrove ecosystems along tropical coastlines in the short and long term. The aim of this study was to assess the environmental risk of recurrent PHS on mangrove ecosystems in Tumaco municipality, Colombian Pacific. Mangrove characteristics and management aspects led to subdividing the study area into 11 units-of-analysis (UAs) for which threats, vulnerability, potential impacts, and risks were assessed based on environmental factors and the formulation and use of indicators in a rating scale with five categories, which are very low, low, moderate, high, and very high. The results showed that all UAs are highly (64%; 15,525 ha) or moderately (36%; 4,464 ha) threatened by PHS, highly (45%; 13,478 ha) or moderately (55%; 6,511 ha) vulnerable to this kind of pollution, and susceptible to high (73%; 17,075 ha) or moderate (27%; 2,914 ha) potential impacts. The environmental risk was high in 73% (17,075 ha) of the UAs, indicating likely irreversible damage to mangrove ecosystems by PHS, thus pointing to the need of urgent intervention by responsible authorities to ease their recovery and conservation. The methodology and results of this study become technical inputs that serve for environmental control and monitoring, which can be incorporated into contingency and risk management plans.

Spatial distribution and driving factors of groundwater chemistry and pollution in an oil production region in the Northwest China.

Concerns have been raised on the deterioration of groundwater quality associated with anthropogenic impacts such as oil extraction and overuse of fertilizers. However, it is still difficult to identify groundwater chemistry/pollution and driving forces in regional scale since both natural and anthropogenic factors are spatially complex. This study, combining self-organizing map (SOM, combined with K-means algorithm) and principal component analysis (PCA), attempted to characterize the spatial variability and driving factors of shallow groundwater hydrochemistry in Yan'an area of Northwest China where diverse land use types (e.g., various oil production sites and agriculture lands) coexist. Based on the major and trace elements (e.g., Ba, Sr, Br, Li) and total petroleum hydrocarbons (TPH), groundwater samples were classified into four clusters with obvious geographical and hydrochemical characteristics by using SOM - K-means clustering: heavily oil-contaminated groundwater (Cluster 1), slightly oil-contaminated groundwater (Cluster 2), least-polluted groundwater (Cluster 3) and NO3- contaminated groundwater (Cluster 4). Noteworthily, Cluster 1, located in a river valley with long-term oil exploitation, had the highest levels of TPH and potentially toxic elements (Ba, Sr). Multivariate analysis combined with ion ratios analysis were used to determine the causes of these clusters. The results revealed that the hydrochemical compositions in Cluster 1 were mainly caused by the oil-related produced water intrusion into the upper aquifer. The elevated NO3- concentrations in Cluster 4 were induced by agricultural activities. Water-rock interactions (e.g., carbonate as well as silicate dissolution and precipitation) also shaped the chemical constituents of groundwater in clusters 2, 3, and 4. In addition, SO42--related processes (redox, precipitation of sulfate minerals) also affected groundwater chemical compositions in Cluster 1. This work provides the insight into the driving factors of groundwater chemistry and pollution which could contribute to groundwater sustainable management and protection in this area and other oil extraction areas.

CO2 improves the anaerobic biodegradation intensity and selectivity of heterocyclic hydrocarbons in heavy oil.

Heterocyclic hydrocarbons pollution generated by oil spills and oilfield wastewater discharges threatens the ecological environment and human health. Here we described a strategy that combines the greenhouse gas CO2 reduction with microbial remediation. In the presence of nitrate, CO2 can improve the biodegradation efficiency of the resins and asphaltenes in heavy oil, particularly the biodegradation selectivity of the polar heterocyclic compounds by the newly isolated Klebsiella michiganensis. This strain encoded 80 genes for the xenobiotic biodegradation and metabolism, and can efficiently utilize CO2 when degrading heavy oil. The total abundance of resins and asphaltenes decreased significantly with CO2, from 40.816% to 26.909%, to 28.873% with O2, and to 36.985% with N2. The transcripts per million (TPM) value of accA gene was 57.81 under CO2 condition, while respectively 8.86 and 21.23 under O2 and N2 conditions. Under CO2 condition, the total relative percentage of N1-type heterocyclic compounds was selectively decreased from 32.25% to 22.78%, resulting in the heavy oil viscosity decreased by 46.29%. These results demonstrated a novel anaerobic degradation mechanism that CO2 can promote the anaerobic biodegradation of heterocyclic hydrocarbons in heavy oil, which provides a promising biotreatment technology for the oil-contaminated water.

Treatment of drilling fluid waste during oil and gas drilling: a review.

Oil and gas exploration and development provide important energy sources for the world, and drilling fluid is an essential engineering material for oil and gas exploration and development. During the drilling of oil wells, drilling fluids are eventually discarded as waste products after many cycles. Abandoned drilling fluid constitutes one of the largest wastes generated during oil and gas exploration and development. Drilling fluid contains many chemicals, which turn into pollutants during use. Furthermore, when drilling is carried out to reach reservoir, the drilling fluid becomes contaminated with crude oil. It may also mix with groundwater containing salts and heavy metals. The resulting pollutants and harmful substances threaten the environment, humans, animals, and plants. The variety and complexity of drilling fluid waste have increased in recent years. Various countries and regions are paying more attention to the ecological environment, and effective methods are urgently needed to solve problems associated with of environmental pollution caused by drilling fluid wastes. At present, various physical, chemical, and biological methods have been proposed for the treatment of drilling fluid wastes: safe landfilling, stabilization/solidification treatment, physicochemical treatment, thermal treatment, supercritical fluid treatment, bioremediation, etc. All of these methods show promising characteristics, and they each have advantages and limitations; thus, treatment methods need to be selected according to the actual application scenarios. This critical overview is based on an extensive literature review, and it summarizes and expounds on the current drilling fluid waste treatment technologies and proposes views future potential and outlook.

Health conditions of Hitnü indigenous people potentially exposed to crude oil in Arauca, Colombia / Condiciones de salud de los indígenas hitnü potencialmente expuestos a petróleo crudo (Arauca, Colombia)

Introduction: The Hitnü indigenous people live in precarious sanitary conditions, with food insecurity and being victims of sociopolitical violence in Arauca, Colombia. In addition, it is possible that they may be affected by exposure to hydrocarbons found in oil. Objective: To identify the health outcomes of morbidity and mortality profiles of the Hitnü people that could be associated with the exposure to crude oil. Materials and methods: A cross-sectional study was carried out with Hitnü indigenous people, during February and March, 2021, time of drought. A household questionnaire was applied, and one individual to collect data from the environment around the house, occupations and other activities, as well as data from sociodemographic, signs, symptoms, and findings of a medical examination. The potential association with hydrocarbons was explored considering three groups: inhabitants in Arauca city, Aspejaná reserve (not exposed), and San José del Lipa and La Vorágine reserves (exposed by the Ele river and tributaries). With free listings, causes of death were explored. The study incorporated a rigorous intercultural management in all its components. Results: A total of 576 indigenous people from 16 settlements participated. The water consumed could serve as means of exposure to hydrocarbons. Health problems were very varied, including infectious and chronic diseases, malnutrition, and trauma. The masses on the neck were associated with residing in the ancestral reserves (PR = 3.86; CI95% 1.77-8.39), territories with potential exposure to crude-oil. The most relevant causes of death were homicide, tumors, and tuberculosis. Conclusion: For its possible association with exposure to hydrocarbons, it is a priority to start the intercultural study of lymphadenopathies in indigenous communities potentially exposed to crude oil.

Introducción. El pueblo hitnü vive en condiciones sanitarias precarias, con inseguridad alimentaria y víctima de la violencia sociopolítica en Arauca (Colombia). Además, se sospecha que pueden estar afectados por la exposición a los hidrocarburos del petróleo. Objetivo. Identificar los eventos de salud del perfil de morbilidad y mortalidad de los indígenas hitnü que podrían asociarse con la exposición a petróleo crudo. Materiales y métodos. Se realizó un estudio transversal con indígenas hitnü, durante febrero y marzo de 2021, época de sequía. Se aplicó un cuestionario de hogares y uno individual para recolectar datos del ambiente peridomiciliario, ocupaciones y otras actividades, así como datos sociodemográficos, signos, síntomas y hallazgos de un examen médico. La potencial asociación con los hidrocarburos se exploró considerando tres grupos, según su localización: cabecera de Arauca, resguardo Aspejená (no expuestos) y resguardos de San José del Lipa y La Vorágine (expuestos por su cercanía al río Ele y afluentes). Con listados libres, se exploraron las causas de muerte. El estudio incorporó un riguroso manejo intercultural en todos sus componentes. Resultados. Participaron 576 indígenas de 16 asentamientos. El agua consumida pudo servir como medio de exposición a los hidrocarburos. Los problemas de salud fueron muy variados e incluían enfermedades infecciosas y crónicas, malnutrición y trauma. Las masas en el cuello se asociaron con residir en los resguardos ancestrales (RP=3,86; IC95% 1,77-8,39), territorios potencialmente expuestos al petróleo. Las causas de muerte más relevantes fueron el homicidio, los tumores y la tuberculosis. Conclusión: Por su posible asociación con los hidrocarburos, es prioritario el estudio intercultural de linfoadenopatías entre indígenas potencialmente expuestos al petróleo.

Condiciones de salud de los indígenas hitnü potencialmente expuestos a petróleo crudo (Arauca, Colombia) / Health conditions of Hitnü indigenous people potentially exposed to crude oil in Arauca, Colombia

Introducción. El pueblo hitnü vive en condiciones sanitarias precarias, con inseguridad alimentaria y víctima de la violencia sociopolítica en Arauca (Colombia). Además, se sospecha que pueden estar afectados por la exposición a los hidrocarburos del petróleo. Objetivo. Identificar los eventos de salud del perfil de morbilidad y mortalidad de los indígenas hitnü que podrían asociarse con la exposición a petróleo crudo. Materiales y métodos. Se realizó un estudio transversal con indígenas hitnü, durante febrero y marzo de 2021, época de sequía. Se aplicó un cuestionario de hogares y uno individual para recolectar datos del ambiente peridomiciliario, ocupaciones y otras actividades, así como datos sociodemográficos, signos, síntomas y hallazgos de un examen médico. La potencial asociación con los hidrocarburos se exploró considerando tres grupos, según su localización: cabecera de Arauca, resguardo Aspejená (no expuestos) y resguardos de San José del Lipa y La Vorágine (expuestos por su cercanía al río Ele y afluentes). Con listados libres, se exploraron las causas de muerte. El estudio incorporó un riguroso manejo intercultural en todos sus componentes. Resultados. Participaron 576 indígenas de 16 asentamientos. El agua consumida pudo servir como medio de exposición a los hidrocarburos. Los problemas de salud fueron muy variados e incluían enfermedades infecciosas y crónicas, malnutrición y trauma. Las masas en el cuello se asociaron con residir en los resguardos ancestrales (RP=3,86; IC95% 1,77-8,39), territorios potencialmente expuestos al petróleo. Las causas de muerte más relevantes fueron el homicidio, los tumores y la tuberculosis. Conclusión. Por su posible asociación con los hidrocarburos, es prioritario el estudio intercultural de linfoadenopatías entre indígenas potencialmente expuestos al petróleo.

Introduction. The Hitnü indigenous people live in precarious sanitary conditions, with food insecurity and being victims of sociopolitical violence in Arauca, Colombia. In addition, it is possible that they may be affected by exposure to hydrocarbons found in oil. Objective. To identify the health outcomes of morbidity and mortality profiles of the Hitnü people that could be associated with the exposure to crude oil. Materials and methods. A cross-sectional study was carried out with Hitnü indigenous people, during February and March, 2021, time of drought. A household questionnaire was applied, and one individual to collect data from the environment around the house, occupations and other activities, as well as data from sociodemographic, signs, symptoms, and findings of a medical examination. The potential association with hydrocarbons was explored considering three groups: inhabitants in Arauca city, Aspejaná reserve (not exposed), and San José del Lipa and La Vorágine reserves (exposed by the Ele river and tributaries). With free listings, causes of death were explored. The study incorporated a rigorous intercultural management in all its components. Results. A total of 576 indigenous people from 16 settlements participated. The water consumed could serve as means of exposure to hydrocarbons. Health problems were very varied, including infectious and chronic diseases, malnutrition, and trauma. The masses on the neck were associated with residing in the ancestral reserves (PR = 3.86; CI95% 1.77-8.39), territories with potential exposure to crude-oil. The most relevant causes of death were homicide, tumors, and tuberculosis. Conclusion. For its possible association with exposure to hydrocarbons, it is a priority to start the intercultural study of lymphadenopathies in indigenous communities potentially exposed to crude oil.

Assessing some Cladosporium species in the biodegradation of petroleum hydrocarbon for treating oil contamination.

AIM: Biodegradation is a cost-effective and eco-friendly treatment for oil-contaminated materials using microorganisms. Bacteria and fungi can degrade petroleum by using it as an energy source and this may provide an enormous scope to remediate soils contaminated with petroleum and oil. This study aimed to assess the biodegradation of petroleum hydrocarbons by certain Cladosporium species. METHODS AND RESULTS: By using traditional and spectroscopic assessment analysis, qualitative screening was carried out using Cladosporium spores isolated from air and cultured on mineral salt medium supplemented with petroleum hydrocarbon as the sole carbon source, followed by quantitative assessment using gas chromatography-mass spectroscopy. Nineteen Cladosporium strains from a total of 212 isolates exhibited remarkable capability to degrade petroleum hydrocarbon, representing four species (C. herbarum, C. macrocarpum, C. sphaerospermum, and C. cladosporioides). The results were expressed in terms of biodegradation percentage and optical density of hydrocarbon using a standard calibration curve. The highest reduction of petroleum hydrocarbon was observed with five Cladosporium strains belonging to two species (C. sphaerospermum and C. cladosporioides). CONCLUSION: This study succeeded in isolating several Cladosporium strains (from the air) with a high ability to degrade crude oil that can be used as biological agents to control petroleum pollution in soils and seas. The addition of a surfactant (Tween 80) enhanced the degradation of crude oil reaching a final concentration of 0.4%. Based on these results, the present study could indicate some unique prospects in the field of bioremediation and biodegradation of petroleum-contaminated soil. SIGNIFICANCE AND IMPACT OF STUDY: This study gives unique prospects in the field of bioremediation and biodegradation of petroleum-contaminated soil.

Improving soil fertility by driving microbial community changes in saline soils of Yellow River Delta under petroleum pollution.

It is promising to use indigenous microorganisms for fertility improvement in petroleum-contaminated coastal soil. As a result, the microbial community and physicochemical property are the base for the restoration. For the detailed information, the Phragmites Communis (P), Chinese Tamarisk (C), Suaeda salsa (S), and new Bare Land (B) soil of Yellow River Delta was 90 g in 100 mL sterile bottles simulated at 25 °C with soil: petroleum = 10:1 in the incubator for four months. The samples were detected at 60 and 120 days along with untreated soil and aged Oil Sludge (O) as control. The results showed that all the samples were alkaline (pH 7.99-8.83), which the salinity and NO3- content of incubate soil followed the in situ samples as P (1.09-1.72‰, 8.02-8.17 mg kg-1), C (10.61-13.79‰, 5.99-6.07 mg kg-1), S (10.19-12.43‰, 3.64-4.22 mg kg-1), B (31.85-32.45‰, 3.56-3.72 mg kg-1) and O (31.61-34.30‰, 0.89-0.90 mg kg-1). NO3- and organic carbon decreased after incubation, which the polluted samples (86.63-92.63 g kg-1) still had higher organic carbon than untreated ones with more NH4+ consumption. The high-throughput sequence results showed that the Gammaproteobacteria and Alphaproteobacteria were dominant in all samples, while sulfate reducting bacteria Alphaproteobacteria decreased at 120 days. Meanwhile, the electroactive Gammaproteobacteria might symbiosis with Methanosaetaceae and Methanosarcinaceae, degrading petroleum after electron receptors depletion. Nitrososphaeraceae and Nitrosopumilaceae oxidise NH4+ to NO2- for intra-aerobic anaerobes and denitrifying bacteria producing oxygen for biodegradation in polluted Phragmites Communis soil. The halotolerant Halomicrobiaceae and Haloferacaceae predominated in saline Chinese Tamarisk, Suaeda Salsa and Bare Land, which were potential electroactive degradater. As the ageing sludge formed, the hydrogen trophic methanogens Methanothermobacteraceae (73.90-92.72%) was prevalent with the petroleum pollution. In conclusion, petroleum initiated two-phase in the sludge forming progress: electron acceptor consumption and electron transfer between degradater and methanogens. Based on the results, the domestic sewage N, P removal coupling and electron transport will be the basement for polluted soils fertility improvement.

Desastres com petróleo e ações governamentais ante os impactos socioambientais e na saúde: scoping review / Oil disasters and government actions in the face of social, environmental, and health-related impacts: A scoping review

RESUMO Este artigo teve por objetivo analisar as ações desenvolvidas pelos governos para o enfrentamento dos impactos socioambientais e na saúde em decorrência dos desastres envolvendo petróleo no mundo. Trata-se de uma revisão de escopo realizada na Bireme, Lilacs, SciELO, PubMed, Cochrane Library e Embase, considerando artigos publicados entre 1973 e 2021. As buscas efetuadas nas bases de dados resultaram em 22 artigos sobre 10 desastres de petróleo ao redor do mundo em três continentes (Ásia, América e Europa), cujas causas dos desastres foram encalhe (3), naufrágio (1), colisão (2), derrame (3) e explosão (1). As ações desenvolvidas foram caracterizadas como intersetoriais, econômicas, ambientais e na saúde, sendo que as mais frequentes foram ações ambientais e econômicas. Nas ações desenvolvidas, observaram-se críticas ao controle, mitigação ou prevenção dos danos instantâneos ou futuros decorrentes dos desastres por petróleo, sendo essa uma agenda ainda em aberto para os movimentos sociais na luta pela garantia de um ambiente saudável, promotor de saúde e com preservação de toda a sua biodiversidade. Conclui-se que as ações para o enfrentamento dos desastres por petróleo nos diferentes países parecem ter sido incipientes, revelando uma incapacidade governamental de orientar o enfrentamento dos impactos desse evento inusitado.

ABSTRACT This article aims to analyze the actions taken by governments to face the social, environmental, and health impacts of oil spill disasters worldwide. This scoping review was conducted in Bireme, Lilacs, SciELO, PubMed, Cochrane Library, and Embase databases, considering articles published between 1973 and 2021. The database search returned 22 articles on ten global oil disasters in three continents (Asia, the Americas, and Europe), whose causes were grounding (03), shipwreck (01), collision (02), spill (03), and explosion (01). The actions developed were characterized as intersectoral, economic, environmental, and health-related, and the most frequent were environmental and economic actions. In the actions developed, we observed criticisms of controlling, mitigating, or preventing instantaneous or future damages resulting from oil disasters, which is still an open agenda for social movements in the struggle to ensure a healthy, health-promoting environment that preserves all its biodiversity. The actions to face oil disasters in different countries seem incipient, revealing a governmental inability to guide the confrontation of the impacts of this unusual event.

[Advances in the bioaugmentation-assisted remediation of petroleum contaminated soil].

Bioremediation is considered as a cost-effective, efficient and free-of-secondary-pollution technology for petroleum pollution remediation. Due to the limitation of soil environmental conditions and the nature of petroleum pollutants, the insufficient number and the low growth rate of indigenous petroleum-degrading microorganisms in soil lead to long remediation cycle and poor remediation efficiency. Bioaugmentation can effectively improve the biodegradation efficiency. By supplying functional microbes or microbial consortia, immobilized microbes, surfactants and growth substrates, the remediation effect of indigenous microorganisms on petroleum pollutants in soil can be boosted. This article summarizes the reported petroleum-degrading microbes and the main factors influencing microbial remediation of petroleum contaminated soil. Moreover, this article discusses a variety of effective strategies to enhance the bioremediation efficiency, as well as future directions of bioaugmentation strategies.

Evaluation of pyrene and tetracosane degradation by mixed-cultures of fungi and bacteria.

The present study was conducted to compare the efficiency of different microbial mixed-cultures consists of fifteen oil-degrading microorganisms with different combinations. The investigation was targeted toward the removal of 500 mg/l pyrene and 1% w/v tetracosane, as single compounds or mixture. Sequential Fungal-Bacterial Mixed-Culture (SMC) in which bacteria added one week after fungi, recorded 60.76% and 73.48% degradation for pyrene and tetracosane; about 10% more than Traditional Fungal-Bacterial Mixed-Culture (TMC). Co-degradation of pollutants resulted in 24.65% more pyrene degradation and 6.41% less tetracosane degradation. The non-specified external enzymes of fungi are responsible for initial attacks on hydrocarbons. Delayed addition of bacteria and co-contamination would result in higher growth of fungi which increases pyrene degradation. The addition of Rhamnolipid potently increased the extent of pyrene and tetracosane degradation by approximately 16% and 23% and showed twice better performance than Tween-80 in 20 times less concentration. The results indicated the importance of having sufficient knowledge on the characteristics of the contaminated site and its contaminants as well as oil-degrading species. Gaining this knowledge and using it properly, such as the later addition of bacteria (new method of mixed-cultures inoculation) to the contaminated culture, can serve as a promising approach.

Bioremediation perspectives and progress in petroleum pollution in the marine environment: a review.

The marine environment is often affected by petroleum hydrocarbon pollution due to industrial activities and petroleum accidents. This pollution has recalcitrant and persistent compounds that pose a high risk to the ecological system and human health. For this reason, the world claims to seek to clean up these pollutants. Bioremediation is an attractive approach for removing petroleum pollution. It is considered a low-cost and highly effective approach with fewer side effects compared to chemical and physical techniques. This depends on the metabolic capability of microorganisms involved in the degradation of hydrocarbons through enzymatic reactions. Bioremediation activities mostly depend on environmental conditions such as temperature, pH, salinity, pressure, and nutrition availability. Understanding the effects of environmental conditions on microbial hydrocarbon degraders and microbial interactions with hydrocarbon compounds could be assessed for the successful degradation of petroleum pollution. The current review provides a critical view of petroleum pollution in seawater, the bioavailability of petroleum compounds, the contribution of microorganisms in petroleum degradation, and the mechanisms of degradation under aerobic and anaerobic conditions. We consider different biodegradation approaches such as biostimulation, bioaugmentation, and phytoremediation.

Miscanthus x giganteus role in phytodegradation and changes in bacterial community of soil contaminated by petroleum industry.

The second generation energy crop Miscanthus x giganteus (Mxg) was cultivated in pots with mixtures of clean and petroleum industry contaminated soil affected by petroleum, Pb, Zn contamination and high salinity. The survival rate reached 100%, nevertheless the biomass parameters were negatively affected even in the lowest proportion of contaminated soil. In the lowest contamination, where the plant grew still quite successfully, C10-C40 degradation was significantly enhanced compared to the unplanted control with degradation of 58 ± 14%. The plant contribution to aliphatics degradation was significantly correlated with biomass, thus it was negligible in higher contamination. A similar pattern was documented in development of the soil bacterial community. The shift in community structure after Mxg cultivation was observed mainly in the soil with the lowest contaminant proportion, though an increase of bacterial diversity in the miscanthus rhizosphere was observed in all cases. Relative abundance of Actinobacteria was reduced on behalf of several less abundant phyla (Verrucomicrobia, Bacterioides, Acidobacteria). The majority of genera identified as potential petroleum degraders (Pseudomonas, Shinella, Altererythrobacter, Azospirillum, Mesorhizobium, Dyella) were more abundant in contaminated soil with miscanthus, suggesting that Mxg could be a promising crop for phytomanagement of petroleum contaminated soils but salt phytotoxicity needs to be mitigated first.

Phenanthrene alters the electrical activity of atrial and ventricular myocytes of a polar fish, the Navaga cod.

Oil and gas exploration in the Arctic can result in the release of polycyclic aromatic hydrocarbons (PAHs) into relatively pristine environments. Following the recent spill of approximately 17 500 tonnes of diesel fuel in Norilsk, Russia, May 2020, our study focussed on the effects of phenanthrene, a low molecular weight PAH found in diesel and crude oil, on the isolated atrial and ventricular myocytes from the heart of the polar teleost, the Navaga cod (Eleginus nawaga). Acute exposure to phenanthrene in navaga cardiomyocytes caused significant action potential (AP) prolongation, confirming the proarrhythmic effects of this pollutant. We show AP prolongation was due to potent inhibition of the main repolarising current, IKr, with an IC50 value of ~2 µM. We also show a potent inhibitory effect (~55%) of 1 µM phenanthrene on the transient IKr currents that protects the heart from early-after-depolarizations and arrhythmias. These data, along with more minor effects on inward sodium (INa) (~17% inhibition at 10 µM) and calcium (ICa) (~17% inhibition at 30 µM) currents, and no effects on inward rectifier (IK1 and IKAch) currents, demonstrate the cardiotoxic effects exerted by phenanthrene on the atrium and ventricle of navaga cod. Moreover, we report the first data that we are aware of on the impact of phenanthrene on atrial myocyte function in any fish species.

Response of soil bacterial communities to high petroleum content in the absence of remediation procedures.

Oil spills are events that frequently lead to petroleum pollution. This pollution may cause stress to microbial communities, which require long adaption periods. Soil petroleum pollution is currently considered one of the most serious environmental problems. In the present work, processes occurring in the bacterial communities of three soil samples with different physicochemical characteristics, artificially polluted with 12% of crude oil, were investigated in 120-day laboratory experiment. It was found that the total petroleum hydrocarbon content did not decrease during this time; however, the proportion of petroleum fractions was altered. Petroleum pollution led to a short-term decrease in the bacterial 16S rRNA gene copy number. On the basis of amplicon sequencing analysis, it was concluded that bacterial community successions were similar in the three soils investigated. Thus, the phyla Actinobacteria and Proteobacteria and candidate TM7 phylum (Saccaribacteria) were predominant with relative abundances ranging from 35 to 58%, 25 to 30%, and 15 to 35% in different samples, respectively. The predominant operational taxonomic units (OTUs) after pollution belonged to the genera Rhodococcus and Mycobacterium, families Nocardioidaceae and Sinobacteraceae, and candidate class ТМ7-3. Genes from the alkIII group encoding monoxygenases were the most abundant compared with other catabolic genes from the alkI, alkII, GN-PAH, and GP-PAH groups, and their copy number significantly increased after pollution. The copy numbers of expressed genes involved in the horizontal transfer of catabolic genes, FlgC, TraG, and OmpF, also increased after pollution by 11-33, 16-63, and 11-71 times, respectively. The bacterial community structure after a high level of petroleum pollution changed because of proliferation of the cells that initially were able to decompose hydrocarbons, and in the second place, because proliferation of the cells that received these catabolic genes through horizontal transfer.