Risk assessment of heavy metals and total petroleum hydrocarbons (TPHs) in coastal sediments of commercial and industrial areas of Hormozgan province, Iran.

The significant increase in the pollution of heavy metals and organic pollutants, their stable nature, and their high toxicity are gradually becoming a global crisis. In a recent study, a comprehensive assessment of the spatial distribution of heavy metals and total petroleum hydrocarbons (TPHs), as well as an assessment of their ecological risks in the sediments of 32 stations located in commercial and industrial areas (Mainly focusing on petrochemical and power industries, desalination plants and transit Ports) of Hormozgan province (East and West of Jask, Bandar Abbas, Qeshm, and Bandar Lengeh) was performed during 2021-2022. The sediment samples were digested with HNO3, HCl and HF solvents. The concentration of heavy metals was determined with furnace and flame systems of atomic absorption spectrometer. The concentration of heavy metals showed significant spatial changes between stations. The ecological assessment indices between the regions indicated that the stations located in Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan had a higher intensity of pollution than other places and significant risks of pollution, especially in terms of Cr and Ni. The average contamination degree (CD) (14.89), modified contamination degree (MCD) (2.48), pollution load index (PLI) (2.32), and potential ecological risk index (PERI) (100.30) showed the sediments in the area of Shahid Bahonar Port, Suru beach and Khor gorsouzuan, experience significant to high levels of pollution, especially Cr and Ni. Using contamination factor (CF) and Geoaccumulation index (Igeo), Cr was considered the most dangerous metal in the studied areas. Based on the global classification of marine sediment quality for the concentrations of TPHs, the sediments of the studied stations were classified as non-polluted to low pollution. In all regions, indices of the PELq (General toxicity) and CF (Contamination factor) were much lower than 0.1 and 1 respectively, showing the absence of adverse biological effects caused by TPHs in sediments. It is necessary to consider comprehensive and impressive strategies to control and reduce pollution of heavy metals, especially in the areas of Shahid Bahonar Port, Suru Beach, and Khor gorsouzuan, so that the sources of this pollution are required to be identified and managed.

Assessing petroleum contamination in parts of the Niger Delta based on a sub-catchment delineated field assessment.

The Niger Delta in Nigeria is a complex and heavily contaminated area with over 150,000 interconnected contaminated sites. This intricate issue is compounded by the region's strong hydrological processes and high-energy environment, necessitating a science-based approach for effective contamination assessment and management. This study introduces the concept of sub-catchment contamination assessment and management, providing an overarching perspective rather than addressing each site individually. A description of the sub-catchment delineation process using the digital elevation model data from an impacted area within the Delta is provided. Additionally, the contamination status from the delineated sub-catchment is reported. Sediment, surface water and groundwater samples from the sub-catchment were analyzed for total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), respectively. Surface sediment TPH concentrations ranged from 129 to 20,600 mg/kg, with subsurface (2-m depth) concentrations from 15.5 to 729 mg/kg. PAHs in surface and subsurface sediment reached 9.55 mg/kg and 0.46 mg/kg, respectively. Surface water exhibited TPH concentrations from 10 to 620 mg/L, while PAHs ranged from below detection limits to 1 mg/L. Groundwater TPH concentrations spanned 3 to 473 mg/L, with total PAHs varying from below detection limits to 0.28 mg/L. These elevated TPH and PAH levels indicate extensive petroleum contamination in the investigated sediment and water environment. Along with severe impacts on large areas of mangroves and wetlands, comparison of TPH and PAH concentrations with sediment and water quality criteria found 54 to 100% of stations demonstrated exceedances, suggesting adverse biological effects on aquatic and sediment biota are likely occurring.

Development of a green and low-cost method to determine mercury content in sediments affected by oil spill on the Brazilian coast.

Tons of crude oil were found on the Brazilian coast in 2019, and studies assessing its chemical composition are still scarce. This study aimed to develop a new and simple technique of cold vapor generation using infrared irradiation coupled with atomic absorption spectrometry to determine mercury content in sediments contaminated by crude oil. Experimental conditions were evaluated, including formic acid concentration, reactor temperature, and carrier gas flow rate. The accuracy of the method was validated by comparison with mercury contents in a certified reference material (PACS-2). The detection limit was found to be 0.44 µg kg-1. The developed method was applied to determine the total mercury content in marine sediment samples collected from beaches in Ceará State. Mercury concentrations ranged from 0.41 to 0.95 mg kg-1. The proposed method is efficient, simple, low-cost, and adequate for its purpose.

Socio-economic baseline for oil-impacted communities in Ogoniland: towards a restoration framework in Niger Delta, Nigeria.

This study documents the socio-economic baselines in selected oil-impacted communities prior to the commencement of the Ogoni clean-up and restoration project. Adopting mixed approach consisting of semi-structured interviews, focus group discussions (FGDs), key informant interviews (KIIs), and household surveys, we surveyed the pre-remediation socio-economic conditions in the Ogoniland communities between July 2018 and March 2019. Results indicated that almost all respondents (99.6%) agreed that the smell of petroleum products or crude oil was evident in the air they breathed even as there were visible black particles (soot) in the respondents' nostrils, on their clothes, and in water. The respondents described the ambient air as smoky and choked with an offensive smell. The household waters were smelly, brownish, or oily, and most respondents (76%) cannot afford to treat their water. Forty-two percent of the respondents who relied on fishing and farming for a living sought for alternative means of subsistence and acknowledged that oil pollution caused stunted growth and low crop yield. The majority of respondents (91%) reported falling fish catches, while the fish caught smell and taste of oil, lowering their market value and posing a potential health risk to consumers. It is evident that oil pollution has impacted the socio-ecological values and sustainable livelihood in Ogoniland. This study provides baseline data for monitoring post-remediation socio-economic improvements in Ogoniland. It also highlights areas of urgent intervention to improve livelihood, and access to basic amenities (e.g., potable drinking water), waste management infrastructure, and statutory policy changes for sustainable development in Ogoniland.

Polycyclic Aromatic Hydrocarbons (PAHs) in aquatic ecosystem exposed to the 2020 Baghjan oil spill in upper Assam, India: Short-term toxicity and ecological risk assessment.

This study focuses on the short-term contamination and associated risks arising from the release of Polycyclic Aromatic Hydrocarbons (PAHs) due to the 2020 Baghjan oil blowout in upper Assam, India. Shortly after the Baghjan oil blowout, samples were collected from water, sediment, and fish species and examined for PAHs contents. The results of the analysis revealed ΣPAHs concentrations ranged between 0.21-691.31 µg L-1 (water); 37.6-395.8 µg Kg-1 (sediment); 104.3-7829.6 µg Kg-1 (fish). The prevalence of 3-4 ring low molecular weight PAHs compounds in water (87.17%), sediment (100%), and fish samples (93.17%) validate the petrogenic source of origin (oil spill). The geographic vicinity of the oil blowout is rich in wildlife; thus, leading to a significant mass mortality of several eco-sensitive species like fish, plants, microbes, reptiles, amphibians, birds and mammals including the Gangetic River dolphin. The initial ecological risk assessment suggested moderate to high-risk values (RQ >1) of majority PAHs concerning fish, daphnia, and algae species. This study highlights the need for recognizing the potential for short-term exposure to local species. To safeguard local ecosystems from potential future environmental disasters, it is imperative for the government to adopt a precautionary strategy.

Methodology for the estimation of an oil spill origin: Analysis of the 2019 Brazilian coast oil spill.

This research presents a procedure for determining the origin of marine pollution through the use of a time-direct trajectory modeling, associated with a Kriging metamodel technique and Monte Carlo random sampling. These methods were applied to a real case, specifically the oil spill that affected the Brazilian coast in the second half of 2019 and early 2020. A total of 140 trajectories, defined by the geographical coordinates of the origin and the spill date, were generated through Latin Hypercube Sampling and simulated using the PyGNOME model to construct the Kriging metamodel. The metamodel demonstrated cost-effectiveness by efficiently simulating numerous input data combinations which were compared and optimized based on available real data regarding temporal and spatial pollution distribution.

A hybrid Monte Carlo simulation risk model for oil exploration projects.

A new 3-D Hybrid Monte Carlo Simulation (MCS) Risk Model is proposed in this study. The wind, wave, current, climate change, and tsunami sub-models of the Three-Dimensional Hydrodynamic Transport and Water Quality Model HYDROTAM-3D are interrelated with MCS, to obtain probability distributions for the simulation of environmental conditions. This is the only model that can incorporate the tsunami, storm, and sea level rise risks in oil exploration projects. The spill risk index (SRI) of 50 blue barrels spilled due to a blowout from the rig/port during fuel supply was circa 1 ton/ship as Tier I with an average annual occurrence probability of 1.0 × 10-6. The discharge of 4000 bbls for 6 h was modeled, resulting in the SRI of 546 metric tons from the riser blowout with SRI = 0.2 per meter, indicating a Tier II risk. The mean arrival time of this spill was found by MCS as 145 min.

Assessment of the effect of short-term weathering on the molecular-level chemical composition of crude oils in contact with aquatic environments.

Multiple studies have focused on the effect of long-term weathering processes on oils after spill events, without considering the chemical compositional changes occurring shortly after the release of oil into the environment. Therefore, the present study provides a broad chemical characterization for understanding of the changes occurring in the chemical compositions of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from the Sergipe-Alagoas basin submitted to two simulated situations, one under marine conditions and the other in a riverine environment. Samples of the oils were collected during the first 72 h of contact with the simulated environments, followed by evaluation of their chemical compositions. SARA fractionation was used to isolate the resins, which were characterized at the molecular level by UHRMS. The evaporation process was highlighted, with the GC-FID chromatographic profiles showing the disappearance of compounds from n-C10 until n-C16, as well as changes in the weathering indexes and pristane + n-C17/phytane + n-C18 ratios for the crude oils submitted to the riverine conditions. Analysis of the resins fraction showed that basic polar compounds underwent little or no alterations during the early stages of weathering. The marine environment was shown to be much less oxidative than the riverine environment. For both environments, a feature highlighted was an increase of acidic oxygenated compounds with the increase of weathering, especially for the crude oil with °API = 27.0.

Risk assessment of marine oil spills using dynamic Bayesian network analyses.

Oil spills are serious threats to the marine ecosystem. Especially when an oil spill is faced with extreme weather, the consequences might be more severe. Until now, no such researches focus on the risk of these extreme scenarios. This paper proposes a novel dynamic assessment method to quantify the risk of oil spills in extreme winds based on dynamic Bayesian networks (DBNs). The physical models of advection, spreading, evaporation, and dispersion are transformed into DBNs, and the vulnerability model is established according to coastline types and socio-economic resources. By integrating all the sub-models, the overall DBN to quantify the dynamic risk of oil spills occurring in extreme winds is obtained. The proposed method is demonstrated by the Laizhou Bay. The developed model is validated by a three-axiom-based approach. Temporal and spatial dynamics of risk caused by oil spills in potential locations could be calculated. Based on the developed DBN, the risk of the Laizhou Bay coast caused by oil spills in annual extreme wind speeds corresponding to different mean recurrence intervals is studied. In addition, the effects of the occurrence time of annual extreme winds are also researched.

Community-based assessment of marine resources contamination after a large-scale oil spill.

As of August 2019, several oil slicks reached the Brazilian coast, compromising local ecosystems and the economy of coastal communities. In this context, this study aimed to assess seafood quality at the Canavieiras Extractive Reserve (RESEX), located in the state of Bahia, Northeastern Brazil, by determining polycyclic aromatic hydrocarbons (PAHs) concentrations in local biota following the oil spill. It was designed and carried out in a participatory manner, involving RESEX fishers, shellfish and crab gatherers and managers, as well as university researchers. A total of 72 biota samples were analyzed, and the sum of the 16 priority USEPA PAHs ranged from less than the limit of detection to 30.81 ng g-1 (w.w.). When also considering alkylated compounds, concentrations ranged from 3.53 to 360.75 ng g-1 (w.w.). No sample contained PAHs concentrations suggestive of human consumption risks. No difference in PAHs concentrations between the six studied areas and regarding different biota feeding habits were observed. Higher PAHs concentrations were generally noted in molluscs, as these organisms do not have enzyme systems capable of metabolizing these compounds. This initiative demonstrated the feasibility of participatory construction resulting in a study concerning valued species to local communities, ensuring a contribution to local fishing and marketing activities.

Assessment of bioremediation potential of petroleum-contaminated soils from the shanbei oilfield of China revealed by qPCR and high throughput sequencing.

With the crude oil exploration activities in the Shanbei oilfield of China, the risk of soil contamination with crude oil spills has become a major concern. This study aimed at assessing the bioremediation potential of the petroleum polluted soils by investigating the expression of key functional genes decoding alkane and aromatic component degradation using an array of primers and real-time quantitative PCR (qPCR), and the functional microbiomes were determined using a combination of substrate-induced metabolic responses and high throughput sequencing. The results showed that the species that were more inclined to degrade aliphatic fraction of crude oil included Acinetobacter, Stenotrophomonas, Neorhizobium and Olivebacter. And Pseudomonas genus was a highly specific keystone species with the potential to degrade PAH fraction. Both aliphatic and PAH-degrading genes were upregulated when the soil petroleum contents were less than 10,000 mg/kg but downregulated when the oil contents were over 10,000 mg/kg. Bioremediation potential could be feasible for medium pollution with petroleum contents of less than 10,000 mg/kg. Optimization of the niche of Acinetobacter, Stenotrophomonas, Pseudomonas, Neorhizobium and Olivebacter species was beneficial to the biodegradation of refractory hydrocarbon components in the Shanbei plateau oilfield.

Optimisation of the uncertainty of oil spill identification from replicate comparative analyses: Comparison of standardised and novel identification methods.

Oil spill identifications involve the comparison of oil fingerprints between the oil spill and suspected oil sources, defined by ratios between the abundances of oil-discriminating compounds, Diagnostic Ratios (DR). The normalised Nordtest and EN 15522-2 methodologies use Student's t statistic (S-t) or a maximum relative difference (SC) to compare mean DR from replicate sample analysis. While the S-t method assumes the normality of DR distribution, the SC method is based on controlled DR dispersion. However, when false, the assumptions and approximations adopted can lead to low true identification rates. This work presents a novel computational tool for the statistically sound oil spill identification that allows following requirements defined by EN 15522-2, the comparison of replicate DR determinations, and the use of different DR sets and formats. The tool uses the Monte Carlo Method (MCM) to describe the probability distribution of the difference of mean DR, allowing estimating the probability of the true acceptance of fingerprints equivalence. The studied methods were applied to the comparison of signals from the same oil and to a real scenario reproduced in an International Round Robin Test. The methods were compared considering the probabilities of true acceptance of oil patterns equivalence based on a single, γ, or various, δ, DR. The MCM method performs identifications with γ equivalent to the defined confidence level for the comparison, P. Since the various DR studied are not perfectly correlated, the δ is below P. The number of replicate analyses performed and the DR considered in the comparison affect identification performance. The S-t produces comparison criteria with a γ lower than P. The SC criteria for duplicate analysis is associated with a δ lower than the obtained by the MCM. A user-friendly MS-Excel spreadsheet is available to perform oil pattern comparisons using various methods and conditions.

Pollution level and health risk assessment of the total petroleum hydrocarbon in marine environment and aquatic products: a case of China.

To evaluate the pollution level and health risk of total petroleum hydrocarbon (TPH), seawater, sediments, and aquatic organisms were sampled from the southern sea area of Zhejiang Province (Yangtze River Delta, China) between 2017 and 2019. TPH was widely present in the aquatic environment and products, and its concentration was highly variable. The average value of pollution index (PI) exceeded 1 from 2017 to 2018, and 45.46-69.19% of seawater samples and 56.87-50.00% of sediment samples were polluted. The results showed significant differences in the TPH concentration in various species of aquatic organisms. The average TPH value in aquatic organisms could be ranked in the order as follows: bivalve > shrimp > crab > fish, further reflecting that the ability to accumulate and metabolize TPH existed differently among aquatic organisms within the same pond aquaculture environment. It was relatively safe to eat aquatic products since the exposure risk index was found to be far below the threshold value in this study. Therefore, it would be prudent to undertake regular monitoring of TPH to ensure effective ecosystem functioning and seafood safety in the southern Zhejiang ocean.

PAHs impacts on aquatic organisms: contamination and risk assessment of seafood following an oil spill accident.

Oil spills, intrinsically related to the petroleum production chain, represent a risk to the marine environment and a potential threat to humans through seafood consumption. We revised the NE Brazil oil spill and other accidents along the Brazilian coast, with a focus on seafood contamination, covering topics such as bioaccumulation, bioaccessibility, and risk analysis. Comprehensive knowledge of the impacts of spills helps in the interpretation of the dynamics of hydrocarbons released into the sea, contributing to actions to control their negative impacts. Currently, no legal limits have been established permanently in Brazil for PAHs in seafood edible tissues.

Best available technique for the recovery of marine benthic communities in a gravel shore after the oil spill: A mesocosm-based sediment triad assessment.

Ecotoxicological effects of spilled oils are well documented, but study of recovery of marine benthic communities is limited. Long-term recovery of hard bottom communities during physical and biological remediations after a spill was monitored. A 60-day experiment was conducted using a mesocosm with monitoring of eight endpoints by use of the sediment quality triad (SQT). First, physical treatment of hot water + high pressure flushing maximally removed residual oils (max=93%), showing the greatest recovery among SQT variables (mean=72%). Physical cleanup generally involved adverse effects such as depression of the microphytobenthic community during the initial period. Next, biological treatments, such as fertilizer, emulsifier, enzyme and augmentation of the microbes, all facilitated removal of oil (max=66%) enhancing ecological recovery. Analysis of the microbiome confirmed that oil-degrading bacteria, such as Dietzia sp. and Rosevarius sp. were present. A mixed bioremediation, including fertilizer + multi-enzyme + microbes (FMeM) maximized efficacy of remediation as indicated by SQT parameters (mean=47%). Natural attenuation with "no treatment" showed comparable recovery to other remediations. Considering economic availability, environmental performance, and technical applicability, of currently available techniques, combined treatments of physical removal via hand wiping followed by FMeM could be most effective for recovery of the rocky shore benthic community.

Evaluation of offshore oil spill response waste management strategies: A lifecycle assessment-based framework.

This study presents a novel life cycle assessment-based framework for low-impact offshore oil spill response waste (OSRW) management. The framework consists of design of experiment, life cycle assessment (LCA), multi-criteria decision analysis (MCDA), operational cost analysis, and generation of regression models for impact prediction. The framework is applied to four OSRW management strategies as different combinations of solid and liquid oily waste collection, segregation, transportation, and treatment/disposal technologies. Hypothetical scenarios based on oily waste compositions are developed, and the associated environmental impacts and operational costs are evaluated. The LCA results show that oily waste composition accounts for < 5% of the total environmental impacts. Chemical demulsification has the highest total impacts due to high marine ecotoxicity and human toxicity, followed by incineration and transportation. The cost analysis reveals that the strategy comprised of centrifugation and landfilling is most preferable while the combination of chemical demulsification and incineration is least favorable. The strategy of combined use of centrifugation and landfilling is ranked as the most suitable in the MCDA. Regression models are developed to predict environmental impacts based on important factors. The framework can help waste management practitioners select low-impact strategies for handling offshore OSRW.

History of a disaster: A baseline assessment of the Wakashio oil spill on the coast of Mauritius, Indian Ocean.

Oil spills from tanker ships provide adverse and irreversible impacts of a pollutant over coastal and marine environments. Using Sentinel-1 and 2 satellite images, this baseline paper presents the detection, assessment, and monitoring of the aground and further oil spill from the Wakashio ship of August 06, 2020, on the Mauritius coast. The oil spill started on August 06, after cracks developed on the hull, and continued until the total breakup of the ship on August 15, 2020. Data shows displacements in ship position of about 100 m, and a maximum change of 80° in orientation (from NS to NE). The remote sensing results were validated using met-ocean observations and reanalysis, which showed winds, waves, and tides of high magnitude at the accident site during the incident period. Analysis of the results of this event using REAS and CMEMS data indicate their usefulness to study similar future oil spills events.

Development and validation of statistically sound criteria for the match of unweathered GC-MS fingerprints in oil spill forensics.

The investigation of an oil spill's origin frequently relies on determining the equivalence of oil component patterns in samples from the contaminated environment and suspected oil source. This comparison benefits if based on the ratio of the abundance of unweathered characteristic components of the oil product, Diagnostic Ratios, DR. Replicate determinations of DR from one sample are used to set limits for the second sample's DR. The composition equivalence of oil patterns in both samples is indicated if all compared DR are statistically equivalent with a high confidence level. Some studies define DR limits assuming their normality and using Student's t statistics (S-t). However, since the ratio of correlated abundances can be not normally distributed, this criterion can drive to more false comparisons than predicted by the test confidence level. This work developed a computational tool for the reliable description of the non-normal distribution of the DR based on the Monte Carlo Method (MCM), aiming to allow the accurate control of the confidence of DR comparison. This work concluded that S-t defines 95% or 98% confidence limits with probabilities of falsely rejecting samples equivalence, φ, that can be up to 4.3% higher than predicted by the confidence level of the S-t test (i.e., 5% and 2%). The fragilities of the S-t limits significantly reduce the probability (1-θ) of two samples with the same oil producing equivalent values of all compared DR. For the studied 69 DR from unweathered components, the (1-θ) for 98% confidence level limits, set by the MCM and S-t from triplicate injections of one sample, are 94.8% and 91.7%, respectively. These values are below the confidence level (P) defined for each DR because DR are correlated with a correlation coefficient lower than 1. The (1-θ) can be increased to above P by using MCM limits and accepting composition equivalence if at least one of two sample extract injections produces values within limits set from the other sample's replicate injection. The validated user-friendly MS-Excel file used to set and access comparison criteria is made available as Supplementary Material and was checked experimentally. However, it is not feasible to estimate model confidence exclusively from experimentation because it would require too much independent analysis.

Who has sustained psychological symptoms nine years after the Hebei Spirit oil spill?: The Health Effect Research on Hebei Spirit oil spill (HEROS) study.

This study evaluated risk factors for sustained psychological symptoms in affected residents, nine years after the Hebei Spirit oil spill in Korea in 2007. The participants included residents of high-exposure areas, living within 2 km from the contaminated coast (n = 2013), among the cohort of the Health Effect Research on Hebei Spirit oil spill study from 2009 to 2016. Symptoms for post-traumatic stress disorder (PTSD), depression, psychosocial distress, and anxiety, as well as sociodemographic information were assessed through questionnaire interviews. Trajectory analysis was conducted to identify the group with sustained symptoms over time and logistic regression analysis was performed to identify risk factors for sustained symptoms adjusted for covariates. A longer duration of clean-up work, lower household income, and presence of a chronic disease in all type of symptoms, and being female, younger age, and higher educational level in all symptoms but PTSD, showed a significant association with increased risk of sustained symptoms. The highest risk was found in the subgroup with a longer clean-up together with offshore and maritime occupations or lower income in PTSD, depression, and anxiety, compared with those with a shorter clean-up and other occupation or higher income. Increased risk of sustained PTSD in relation to a longer clean-up was limited to those with a lower educational level (p-interaction = 0.009). The results suggested that participating longer in clean-up work increased sustained psychological symptoms, synergistically with socioeconomic factors such as offshore and maritime occupations, lower household income, or economic losses related to educational level.

Development of a dispersibility assessment kit for use on oil spill response vessels.

The use of dispersants can be an effective response tool for large offshore spills by applying dispersants on unemulsified slicks and treating as much oil as possible before it becomes too viscous. Assessing the dispersibility of an oil slick under actual environmental conditions is an important step in spill response decision-making. This research seeks to develop a new field kit that is quick and reliable and could be used by spill response personnel without scientific training. The resulting Dispersibility Assessment Kit (DAK) incorporates an automated mixing unit to standardize the applied energy, thereby eliminating the variability in "hand mixing" that is used in other dispersant field kits. The automated mixing energy was studied to determine the optimal mixing regime that correlates with ocean conditions and was incorporated in the DAK protocol. The DAK was validated against 14 oils and emulsions and was successfully tested by response personnel during at-sea demonstration.