Petroleum hydrocarbons and colored dissolved organic matter shape marine oil-degrading microbiota in different patterns.

Both petroleum hydrocarbons (PHCs) from oil pollution and colored dissolved organic matter (CDOM) have great influences on the marine microbial community as carbon source factors. However, their combined effects and the specific influence patterns have been kept unclear. This study selected the northeastern South China Sea (NSCS), a typical oil contaminated area, and investigated the characteristics of oil-degrading microbiota in the seawaters by high-throughput sequencing and the relationships with PHCs and CDOM as well as other environmental factors. The results showed the oil pollution had induced the enrichment of oil-degrading bacteria and oil-degrading functional genes, resulting in the core function of oil-degrading microbiota for shaping the microbial community. The Mantel test indicated carbon source factors played the dominant role in shaping the oil-degrading microbiota, compared with geographical distance and other non­carbon source factors. The influence patterns and strength of PHCs and CDOM on oil-degrading microbiota were further comprehensively analyzed. PHCs played a driving role in the differentiation of oil-degrading microbiota, while CDOM played a stabilizing role for the community similarity. The constructed structural equation model confirmed their distinct influence patterns and also explored the mediating effects of bulk organic carbon. This work not only revealed the important impact of oil pollution on marine microbial communities, but also made people realize the self-regulation ability of the marine environment through the endogenous organic matter.

Exploring the glycoprotein washing fluid-assisted cleanup for the restoration of oil-contaminated shorelines with environmental integrity.

Spilled oil in ocean can spread to the shoreline and cause long-term impacts on the shoreline's ecological environment. Therefore, removing oil accumulated on shorelines is crucial. This study proposed an innovative ovalbumin (OVA) fluid-assisted method for the cleanup of oiled shoreline substrates. The oil removal efficiency of OVA fluids was systematically investigated. Higher concentrations of OVA fluids effectively enveloped and immobilized the oil, aiding in its separation from the sand surface. The increased temperature reduced the viscosity of emulsions, facilitating improved flow and oil removal. High salinity promoted the creation of oil particle aggregates molecules and facilitated the release of oil from the sand surface. The factorial analysis demonstrated that a high salt environment significantly enhances the combined impact of temperature and pH on oil removal performance. Different methods for the responsive separation of washing effluents were studied, and the most effective separation method was adjusting the pH of effluents to 4.54 (the isoelectric point of OVA). Separated precipitates exhibited good decomposition efficiency through thermal decomposition and biodegradation. OVA fluids boast advantages, such as low cost, easy recyclability, and non-toxicity, while ensuring high oil removal efficiency and making them a promising eco-friendly technique for the cleanup of oiled shorelines.

Multiple endpoints analysis of the effects of diesel oil on a commercial species, Carcinus maenas.

Fuel spills in marine environments pose significant threats to aquatic ecosystems, evidencing the intricate relationship between fuel utilization and its impact on benthic species of commercial value for human consumption. This interconnectedness of human, animal and environmental welfare falls within the One Health framework. The aim of the present study was to evaluate the toxicological effects of diesel oil on the green crab Carcinus maenas, and make a parallelism between tested concentrations and petrogenic hydrocarbon levels in natural environments. Mortality, locomotion and feeding behavior, molting, somatic growth, morphological malformations, stress biomarkers, and nutritional variables were analyzed in three different bioassays. In Bioassay 1, prepuberal females were exposed to diesel oil water accommodated fraction (WAF) to determine the median lethal concentration (LC50) at different periods. In Bioassay 2, prepuberal females were exposed to 168 h LC50 and LC25 of diesel oil WAF for 7 days, and were subsequently exposed to clean water. In Bioassay 3, prepuberal females were exposed to 168 h LC12 and LC6 of diesel oil WAF for 30 days. Petrogenic hydrocarbon levels in the field were quantified at a port and a nature reserve, with concentrations of aromatic hydrocarbons being 1.92 µg/g in the former and below 0.01 µg/g in the latter. In Bioassay 1, the 168 h LC50 was estimated to be 1.04 % of diesel oil. The results obtained in Bioassays 2 (LC50 and LC25) and Bioassays 3 (LC12 and LC6) suggest that environmental exposure to petrogenic hydrocarbons produces high mortality or interferes with the molting process of crabs, leading to reduced growth and developmental abnormalities. Such malformations were observed in chelipeds, pereiopods, gills chambers and eye peduncles, and affected feeding and locomotion behaviors. Overall, this could impact on population size and health, and consequently alter the ecological role and commercial exploitation of economically important species like C. maenas.

Spatial distribution of PAHs, nickel, and vanadium in sediments from a large coastal lagoon near a petroleum extraction area in the southern Gulf of Mexico.

One of the world's crucial areas for crude oil exploration and extraction is the southern Gulf of Mexico, where Terminos Lagoon (TL) is located. Sediments from the TL region were used to assess the spatial patterns, origins, and ecotoxicological risks associated with 16 priority polycyclic aromatic hydrocarbons (PAHs; 3.1-248.9 ng⸳g-1 dry weight basis, dw) and trace metals (Ni = 11.0-104.0 mg⸳kg-1; V = 2.0-35.0 mg⸳kg-1 dw) linked to anthropogenic activities. Although origin indices based on PAHs and metals concentrations indicate no crude oil pollution in the region, sources of pyrogenic PAHs were identified. A chemometric approach demonstrated associations between organic matter and PAHs, and that metal accumulation depends mostly by the input of lithogenic materials. Ecotoxicological risk estimations showed a higher risk of possible adverse effects in sites near swamps and mangrove zones, highlighting the need of future monitoring. This study provides a reference for policymakers to conserve Mexico's largest coastal lagoon and other oil-impacted coastal areas worldwide.

Petroleum hydrocarbon ecological risk and changes induced on macrobenthic communities of a microtidal estuary in South America.

The coastal areas of Montevideo-Canelones, Uruguay, are strongly affected by anthropogenic activities. Polycyclic aromatic hydrocarbons (PAHs) are of especial ecological concern due to their acute toxicity. The study aimed to evaluate the relationship between different pollution levels and the ecological structure of macrobenthic communities of the subtidal coastal zone and to assess the ecological risk of the 16 PAHs identified by US EPA for these communities. Communities in Montevideo Bay are under the influence of combined effects of natural oscillations and anthropic pollution, while the adjacent coastal areas communities are strongly influenced by El Niño Southern Oscillation. Toxicity assessments classified two sites in Montevideo Bay as medium to low risk. This study allowed recognizing the complex nature of the responses of benthic organisms to multiple stressors and the importance of considering different approaches.

Hair and urinary 2-hydroxynaphthalene levels in the people living in a region with frequent oil pipeline incidents in Iran: Health risk assessment.

Oil spills from pipeline accidents can have long-lasting health effects on residents of polluted regions. Assessing the potential health risk of these accidents is crucial for effective environmental health management. This study analyzed the concentration of 2-OHNAP in urine and hair as biomarkers of PAHs exposure among the people living in a region with frequent oil pipeline incident in Iran. Fifty pairs of hair and urine samples were collected from residents along with demographic information and dietary habits via a questionnaire. The concentration of 2-OHNAP was analyzed using high performance liquid chromatography coupled with fluorescence detector (HPLC-FLD). 2-OHNAP was detected in 100% of urine and 88% of hair samples. The mean concentration of 2-OHNAP in urine was 16.65 ± 21.98 µg/g creatinine and in hair was 8.16±7.62 ng/g dry weight (dw). However, there was no significant correlations between the levels of 2-OHNAP in urine and hair. The mean values of HQ and CR were below 1 and 10-6, respectively. Moreover, some simulated health risk indices were near the threshold levels, and the carcinogenic risk above 70% of the simulated CRs was above 10-6 as well. Therefore, the health risk attributed to the exposure to the parent compound of 2-OHNAP in the study area is currently acceptable, but it is not negligible and may be worsened in the future. This study provides a valuable scientific information for regional decision makers and stakeholders about human health programs and identification of environmental health priorities.

Aquatic toxicity and chemical fate of diluted bitumen spills in freshwater under natural weathering.

Increasing global demands for oils are fueling the production of diluted bitumen (DB) from Canada's oil sands region. More weathered than conventional crude (CC) oils, Alberta bitumen is often diluted with lighter petroleum oils to reduce density and viscosity to meet pipeline specifications for transportation. Being a heavy oil product that is transported in large volumes across Canada and the USA, there has been interest to compare its behavior and toxicity characteristics when spilled to those of CC. To determine the influence of environmental weathering upon DB following a freshwater spill, we conducted separate controlled spills of Cold Lake Blend DB and Mixed Sweet Blend light CC oil in a mesocosm spill-tank system at 24 °C with wave-action for 56 days. DB-contaminated waters remained acutely lethal for a period of 14 days to early life stage fathead minnows (Pimephales promelas) exposed during embryologic development, while CC was lethal for 1 day. However, concentrations of mono- and polycyclic aromatic compounds, often claimed to be principally responsible for the acute and chronic toxicity of crude oils, were consistently higher in CC water compared to DB. Elevated aromatic concentrations in CC water correlated with higher prevalences of developmental malformations, reduced heart and growth rates, and impacts on the aryl hydrocarbon receptor pathway. Organic acids were measured over the course of the studies and O2 containing naphthenic acids were present at greater relative abundances in DB- compared to CC-contaminated water, with their attenuation correlating with reduced acute and sublethal toxicity. Furthermore, organic acid degradation products accumulated with time and likely contributed to the consistently sublethal toxicity of the weathered oils throughout the experiment. Improved characterization of the fractions including organic acids and those organic compounds found within the unresolved complex mixture of fresh and weathered crude oils is necessary to adequately understand and prepare for the risks that accidental petroleum spills pose to aquatic resources.

Compositional change of bacterial communities in oil-polluted seawater amid varying degrees of nanoplankton bacterivory.

Petroleum hydrocarbons are being released into the marine environment continuously. They will undergo weathering and may eventually be biodegraded by bacteria and other microbes. While nanoplankton (2-20 µm) are the major consumers of marine bacteria, their effect on the process of biodegradation of oil hydrocarbons is still debated. A 14-day microcosm experiment was conducted to investigate the effects of crude oil hydrocarbons on nanoplankton bacterivory and bacterial community in coastal waters. The coefficients of population growth (0.56-1.80 d-1 for all treatments considered) and grazing mortality (0.38-1.65 d-1 for all treatment considered) of bacteria estimated with the dilution method did not differ among the treatments of control (Ctrl), low dose chemically dispersed oil (LDOil, 2 µL L-1 of crude oil), and high dose chemically dispersed oil (HDOil, 8 µL L-1 of crude oil). Bacterial abundance ranged between 0.21-0.86 × 106 cells mL-1 on average for all treatments. The lack of drastic increases in the cell density of bacterial cells in the oil-loaded treatments was observed throughout the experiment period. Sequencing analysis of the 16S rRNA gene revealed the progressive changes in the community compositions of bacteria in all treatments. The relatively high abundance of oil-degrading bacteria, including Cycloclasticus and Alcanivorax on Days 3-14 of the experiment reflected the presence of biodegradation of oil in the LDOil and HDOil treatments. Throughout the 14 days, the community composition of bacteria in the LDOil and HDOil treatments became more similar and they both differed from that in the Ctrl treatment. This study concluded that, in oil-polluted seawater, the changes in the bacterial community composition were mainly resulting from the addition of chemically dispersed crude oil.

Efficient oil spill cleanup from water: Investigating the effectiveness of a sustainable anti-swelling hydrogel for rapid water repellency and oil absorption.

Considering the significant harm caused to aquatic ecosystems and marine life by oil spills and the discharge of oily wastewater, there is a pressing need to address this issue to protect our environment and prevent the wastage of valuable resources. We introduced a two-step approach to create an anti-swelling, water-repellent sorbent using a green polysaccharide called gum gellan, functionalized with Octadecyl trichlorosilane (OTS) through dip coating method. Natural gums like gellan have high absorption capability due to their large surface area. However, they are hydrophilic, which means they can only absorb water. This property makes them unsuitable for oil spill applications. To make gum gellan suitable for oil spill applications, we have modified it in this study. We have introduced a material called octadecyltrichlorosilane, which has low surface energy and hierarchical roughness. This modification changes the wettability of gellan from hydrophilic to hydrophobic/oleophilic, allowing it to absorb oil and repel water. The sorbent is analyzed using several techniques, such as FTIR, XRD, TGA, FE-SEM, BET, Raman, EDX, and H1-NMR. The hydrophobic sorbent obtained demonstrates low density, high surface area, and high porosity. These characteristics give it excellent floatability and immediate and exceptional selectivity for absorbing oil from water. Additionally, it does not absorb any detectable amount of water. The sorbent exhibited a water contact angle (WCA) of 140 ± 3 ° and an oil contact angle (OCA) of 0° for various oils and organic solvents. It has rapid oil absorption capacity of 3.72 g/g for diesel, and can be easily recovered after use. The BET analysis revealed that after the modification with OTS, the sorbent's total surface area increased from 0.579 m2/g to 4.713 m2/g. This indicates that the OTS modification greatly enhances the surface area and pore volume of the, thus improving its ability to absorb oil. This sorbent efficiently separates oil-in-water emulsions, both surfactant-stabilized and surfactant-free, achieving over 90% separation through gravity alone. Moreover, the sorbent can sustain its wettability even under harsh environmental conditions, including exposure to acids, alkalis, and salts. The absorption data predominantly aligned with the pseudo-2nd-order model. Thus, this sorbent provides a cost-effective alternative for efficiently absorbing and separating oil-water emulsions in households and industries.

Novel, active, and uncultured hydrocarbon-degrading microbes in the ocean.

Given the vast quantity of oil and gas input to the marine environment annually, hydrocarbon degradation by marine microorganisms is an essential ecosystem service. Linkages between taxonomy and hydrocarbon degradation capabilities are largely based on cultivation studies, leaving a knowledge gap regarding the intrinsic ability of uncultured marine microbes to degrade hydrocarbons. To address this knowledge gap, metagenomic sequence data from the Deepwater Horizon (DWH) oil spill deep-sea plume was assembled to which metagenomic and metatranscriptomic reads were mapped. Assembly and binning produced new DWH metagenome-assembled genomes that were evaluated along with their close relatives, all of which are from the marine environment (38 total). These analyses revealed globally distributed hydrocarbon-degrading microbes with clade-specific substrate degradation potentials that have not been reported previously. For example, methane oxidation capabilities were identified in all Cycloclasticus. Furthermore, all Bermanella encoded and expressed genes for non-gaseous n-alkane degradation; however, DWH Bermanella encoded alkane hydroxylase, not alkane 1-monooxygenase. All but one previously unrecognized DWH plume member in the SAR324 and UBA11654 have the capacity for aromatic hydrocarbon degradation. In contrast, Colwellia were diverse in the hydrocarbon substrates they could degrade. All clades encoded nutrient acquisition strategies and response to cold temperatures, while sensory and acquisition capabilities were clade specific. These novel insights regarding hydrocarbon degradation by uncultured planktonic microbes provides missing data, allowing for better prediction of the fate of oil and gas when hydrocarbons are input to the ocean, leading to a greater understanding of the ecological consequences to the marine environment.IMPORTANCEMicrobial degradation of hydrocarbons is a critically important process promoting ecosystem health, yet much of what is known about this process is based on physiological experiments with a few hydrocarbon substrates and cultured microbes. Thus, the ability to degrade the diversity of hydrocarbons that comprise oil and gas by microbes in the environment, particularly in the ocean, is not well characterized. Therefore, this study aimed to utilize non-cultivation-based 'omics data to explore novel genomes of uncultured marine microbes involved in degradation of oil and gas. Analyses of newly assembled metagenomic data and previously existing genomes from other marine data sets, with metagenomic and metatranscriptomic read recruitment, revealed globally distributed hydrocarbon-degrading marine microbes with clade-specific substrate degradation potentials that have not been previously reported. This new understanding of oil and gas degradation by uncultured marine microbes suggested that the global ocean harbors a diversity of hydrocarbon-degrading bacteria, which can act as primary agents regulating ecosystem health.

Hydrocarbon composition of oils spilt on the Brazilian coast in 2019 and 2022.

The chemical composition of spilt oils from events that took place on the north-eastern coast of Brazil in 2019 and 2022 was investigated to better understand their sources, and post-spill processes. Oils from both events originated from different sources, based on their fingerprints, hydrocarbons composition and specific biomarkers, such as the C23 tricyclic terpane and oleanane. Despite the differences, the source rocks share similarities in paleoenvironments and depositional conditions and both oils suffered little weathering, mainly due to evaporation and dissolution. Our findings for 2019 spilt oil reinforce that it is a mixed product, enriched both in lighter n-alkanes and 25-norhopanes. Differently, the 2022 samples exhibited characteristics of a non-processed crude oil that originated from a paraffinic deposit in storage tanks. The molecular composition and diagnostic ratios reported for samples from these spill events help to establish baselines for ongoing monitoring of oil spills in marine ecosystems.

A new ship tracing technology from oil spills based on multi-source data.

Oil spill from ship can cause serious pollution to the Marine environment, but it is very difficult to find and confirm the troublemaker. In order to determine the oil spill ship, this paper proposes a new method to trace the source of ship oil spills and find the suspected ship that spills oil based on SAR imagery, AIS data and related marine environment data. First, we filter AIS data based on position of oil spill areas on remote sensing imagery and convert oil spill areas into trajectory points. Secondly, based on the Lagrangian particle motion model, a bidirectional drift model is proposed to calculate the average similarity between the forward and backward drift results. Finally, the most likely oil spill ship is determined according to the average similarity results. The results of the case study show that the method is effective and practical.

Strategic location model for oil spill response vessels (OSRVs) considering oil transportation and weather uncertainties.

In the event of oil spills in offshore oil and gas projects, containment and dispersion equipment must be sent to the affected areas within a critical time by vessels known as oil spill response vessels (OSRVs). Here, we developed an optimization tool, integrated with an oil spill trajectory simulation model, both in deterministic and stochastic alternatives, to support decision-making during the strategic planning of OSRV operations. The tool was constructed in Python using GNOME for oil spill simulations and the GUROBI to solve the optimization model. The tool was applied to a case study in Brazil and afforded relevant recommendations. In terms of research contributions, we proved the viability of the integration between oil spill simulation and mathematical modeling for OSRV strategic operation planning, we explored the stochasticity of the problem with an innovative strategy and we demonstrated flexibility and easy applicability of the framework on real operations.

Toxicity of the oil spilled on the Brazilian coast at different degrees of natural weathering to early life stages of the zebrafish Danio rerio.

Toxicity of water accommodated fractions (WAF) from the oil spilled on the Brazilian coast at different stages of weathering were investigated using Danio rerio. Weathering stages included emulsified oil that reached the coast (OM) and oil collected 50 days later deposited on beach sand (OS) or adhered to shore rocks (OR). Parent and alkylated naphthalenes decreased whereas phenanthrenes increased from less weathered WAF-OM to more weathered WAF-OS and WAF-OR. More weathered WAF-OS and WAF-OR were more potent inducers of zebrafish developmental delay, suggesting that parent and alkylated phenanthrenes are involved. However, less weathered WAF-OM was a more potent inducer of failure in swim-bladder inflation than more weathered WAF-OS and WAF-OR, suggesting that parent and alkylated naphthalenes are involved. Decreases in heart rates and increased heart and skeletal deformities were observed in exposed larvae. Lowest observed effect concentrations for different developmental toxicity endpoints are within environmentally relevant polycyclic aromatic hydrocarbon concentrations.

Chemical exposure from the Hebei spirit oil spill accident and its long-term effects on mental health.

While evidence indicates that exposure to oil spill incidents can affect mental health, it is unclear whether the mental health effects result from the incident itself or from exposure to associated chemicals. Oil contains chemicals that can impact mental health and these chemicals may have long-term effects due to their persistence in the environment. To address the gap in current knowledge, we conducted cross-sectional and prospective analyses of data from adults who participated in the Health Effects of the Hebei Spirit Oil Spill study. To assess chemical exposure from oil spills, we used indirect exposure indicators such as distance from the contaminated oil band to residences and duration of clean-up work, along with direct exposure indicators such as urine metabolite concentrations of volatile organic compounds and polycyclic aromatic hydrocarbons. Mental health assessments covered posttraumatic stress disorder (PTSD), depression, state anxiety, and trait anxiety. In the cross-sectional analyses, all four mental health issues were found to be associated with proximity to the oil band (p-value<0.05) and showed a positive association with clean-up work duration (p-value<0.05). Cox regression analysis revealed that higher urinary t, t-muconic acid levels were associated with an increased risk of depression (Hazard Ratio [HR] = 1.55, 95 % Confidence Interval [CI] = 1.05-2.28), and elevated 1-hydroxypyrene levels increased the risk of PTSD (HR = 1.60, 95 % CI = 1.03-2.48). Additionally, higher urinary 2-naphthol levels were associated with increased state anxiety (HR = 1.39, 95 % CI = 1.00-1.93) and trait anxiety (HR = 1.64, 95 % CI = 1.15-2.32). These associations persisted even after controlling for distance and duration variables related to psychosocial exposure. Our findings suggest that environmental disaster response plans should prioritize minimizing chemical exposure while also considering the duration and nature of the mental health impacts.

Biochar-mediated bioremediation: a sustainable strategy to increase Avena sativa L. tolerance to crude oil soil contamination.

The present work investigated the effects of different doses of biochar (2.5%, 5%, 10%), a by-product of the pyrolysis of woody biomass, on the growth of oat plants (Avena sativa L., cv "Danko") grown under different crude oil concentrations (0.5%, 1%, 2%, 3%, 6%) added to the soil, evaluating both biometric (i.e. fresh weight) and biochemical (i.e., content of malondialdehyde and proline, and total antioxidant power) parameters. The findings indicate that biochar positively influences the fresh weight of oat plants across all concentrations of crude oil investigated. On the other hand, regarding oxidative stress, measured by malondialdehyde and proline content, biochar led to a significant reduction, with statistical significance observed at biochar concentrations > 2.5% and crude oil levels > 2% (malondialdehyde: ranging from -25% to -38%; proline ranging from -33% to -52%). Soil amendment with biochar increased the total antioxidant power, particularly at biochar concentrations > 2.5% and crude oil levels > 2% (ranging from + 20% to + 98%). These results suggest that biochar has a great potential in mitigating the negative effects of crude oil contamination on plant growth and oxidative stress levels, thereby highlighting its value as a conditioner in contaminated soils.

Pipeline emergency preparedness in Nebraska: Identifying interagency preparedness gaps and proposing solutions.

In Nebraska, there are over 28,000 miles of pipelines that carry various materials, which could impact human health and the natural environment in the event of a leak or spill. Nebraska is heavily reliant on its expansive groundwater supply from the large High Plains aquifer system as well as smaller secondary aquifers. Eighty-eight percent of Nebraska's population utilizes groundwater for personal use, and the state's agricultural sector depends on it for irrigation and livestock care. The ongoing challenges facing the implementation of the proposed Keystone XL pipeline system inspired re-searchers to examine the current state of pipeline emergency preparedness in Nebraska. To do this, a pipeline emergency preparedness workshop was held in November 2021 in Norfolk, Nebraska. Conference participants in-cluded county- and regional-level leadership, local public health departments, tribal representatives, and other organizations. Pipeline emergency responders and other stakeholders were invited to listen to plenary presenta-tions about inland oil spill responses and the current state of Nebraska pipelines and to participate in a facilitated discussion identifying pipeline response challenges and potential solutions. Through a facilitated discussion process, participants identified six general response challenge categories and 24 potential solutions. From those 24 solutions, three were selected as easily implementable solutions-increased joint/coordinated planning, increased pipeline emergency exercising, and increased pipeline emergency train-ing/education. Implementing this work will assist in reducing health risks associated with potential spills.

A study on source identification of contaminated soil with total petroleum hydrocarbons (aromatic and aliphatic) in the Ahvaz oil field.

The oil industry in Khuzestan province (Southwest Iran) is one of the main reasons contributing to the pollution of the environment in this area. TPH, including both aromatic and aliphatic compounds, are important parameters in creating pollution. The present study aimed to investigate the source of soil contamination by TPH in the Ahvaz oil field in 2022. The soil samples were collected from four oil centers (an oil exploitation unit, an oil desalination unit, an oil rig, and a pump oil center). An area outside the oil field was determined as a control area. Ten samples with three replicates were taken from each area according to the standard methods. Aromatic and aliphatic compounds were measured by HPLC and GC methods. The positive matrix factorization (PMF) model and isomeric ratios were used to determine the source apportionment of aromatic compounds in soil samples. The effects range low and effects range median indices were also used to assess the level of ecological risk of petroleum compounds in the soil samples. The results showed that Benzo.b.fluoranthene had the highest concentration with an average of 5667.7 ug/kg in soil samples in the Ahvaz oil field. The highest average was found in samples from the pump oil center area at 7329.48 ug/kg, while the lowest was found in control samples at 1919.4 ug/kg-1. The highest level of aliphatic components was also found in the pump oil center, with a total of 3649 (mg. Kg-1). The results of source apportionment of petroleum compounds in soil samples showed that oil activities accounted for 51.5% of the measured PAHs in soil. 38.3% of other measured compounds had anthropogenic origins, and only 10.1% of these compounds were of biotic origin. The results of the isomeric ratios also indicated the local petroleum and pyrogenic origin of PAH compounds, which is consistent with the PMF results. The analysis of ecological risk indices resulting from the release of PAHs in the environment showed that, except for fluoranthene, other PAHs in the oil exploitation unit area were above the effects range median level (ERM) and at high risk. The results of the study showed that soil pollution by total petroleum hydrocarbons (TPH), both aromatic and aliphatic, is at a high level, and is mainly caused by human activities, particularly oil activities.

A seawater field study of crude and fuel oil depletion in Northern Norway at two different seasons - Chemistry and bacterial communities.

After marine oil spills, natural processes like photooxidation and biodegradation can remove the oil from the environment. However, these processes are strongly influenced by environmental conditions. To achieve a greater understanding of how seasonal variations in temperature, light exposure and the bacterial community affect oil depletion in the marine environment, we performed two field experiments during the spring and autumn. Field systems equipped with a thin oil film of Statfjord, Grane or ULSFO were deployed in northern Norway. Depletion of the total extractable matter was faster during the spring than during the autumn. Statfjord showed faster depletion of n-alkanes during spring, while depletion of polycyclic aromatic hydrocarbons varied between the seasons based on the degree of alkyl-substitutions. ULSFO displayed the overall slowest depletion. Biodegradation of the oils was associated with high abundances of unassigned bacteria during the spring but was governed by Alcanivorax, Cycloclasticus, Oleibacter and Oleispira during the autumn.

Oil uptake via marine snow: Effects on blue mussels (Mytilus sp.).

Accidental oil spills into the ocean can lead to downward transport and settling of oil onto the seafloor as part of marine snow, as seen during the Deepwater Horizon incident in 2010 in the Gulf of Mexico. The arctic and subarctic regions may favor conditions leading to this benthic oil deposition, prompting questions about the potential impacts on benthic communities. This study investigated the effects of oil-contaminated marine snow uptake on the blue mussel (Mytilus sp.). We exposed mussels for four days to 1) oil-contaminated marine snow (MOS treatment), or to 2) chemically-enhanced water-accommodated fraction (CEWAF) of oil plus unaggregated food particles (CEWAF treatment). Both oil treatments received the same nominal concentration of oil and food. Two controls were included: 1) Clean seawater plus unaggregated food (agg-free control) and 2) clean seawater plus marine snow (marine snow control). After the exposure, mussels were allowed to recover for ten days under clean, running seawater. Samples were taken right before and after the exposure period, and after the recovery phase for the following endpoints: distribution (partitioning) of oil compounds between seawater and MOS, and between seawater and mussel tissue; DNA damage (assessed via the comet assay); clearance rate; and condition index [tissue dry weight (g) divided by shell length (mm)]. Some discernable patterns were found in the partitioning of oil compounds between seawater and MOS. However, these patterns did not translate to any significant differences in the partitioning of oil compounds into mussel tissue between the two oil treatments. DNA damage did not exceed background levels (10% tail DNA or less; to be expected in healthy, viable cells) at any sampling time point, but significantly higher DNA damage was observed in CEWAF-T compared to MOS-T mussels after the recovery phase. After the exposure, a significant difference emerged in the clearance rate between the CEWAF treatment and the agg-free control, but not between the MOS treatment and the marine snow control. All mussels except those from the CEWAF treatment exhibited an increased condition index after the exposure time. Together, these results suggest that aggregates could moderate the effects of oil exposure on blue mussels, possibly by providing better, more concentrated nutrition than unaggregated food particles.