Oil Spill Model Research Articles

Assessing the environmental risk posed by a legacy tanker wreck: a case study of the RFA War Mehtar

The ocean floor is littered with thousands of wrecks containing hazardous fuels, lubes, armaments and cargoes that have polluted, are polluting, or will pollute the marine environment. The UK Ministry of Defence manages the environmental risk associated with its ∼5,700 military wrecks through the Wreck Management Programme. This paper explores the methods used to assess the environmental risk associated with the wreck of the Royal Fleet Auxiliary (RFA) tanker RFA War Mehtar, which lies at approximately 39 m depth, 15 nm east of Great Yarmouth, United Kingdom. The methods employed include archival research, computational oil spill modelling combined with sensitivity mapping, environmental sampling and hydrocarbon concentration analysis, multibeam echosounder sonar surveys and neutron backscatter probe measurements. Each method is described, and its efficacy discussed. The archival research was essential to determine what fuel and cargo the RFA War Mehtar sank with; but only when high-resolution multibeam sonar images were combined with the ship’s plans and neutron backscatter measurements from individual tanks could one confidently conclude that the wreck does not pose a significant pollution risk.

An Overview of Oil-Mineral-Aggregate Formation, Settling, and Transport Processes in Marine Oil Spill Models

An oil spill is considered one of the most serious polluting disasters for a marine environment. When oil is spilled into a marine environment, it is dispersed into the water column as oil droplets which often interact with suspended particles to form oil-mineral-aggregate (OMA). Knowing how OMA form, settle, and are transported is critical to oil spill modelling which can determine the fate and mass balance of the spilled volumes. This review introduces oil weathering and movement, and the commonly used numerical models that oil spill specialists use to determine how a spill will evolve. We conduct in-depth reviews of the environmental factors that influence how OMA form and their settling velocity, and we review how OMA formation and transport are modelled. We point out the existing gaps in current knowledge and the challenges of studying OMA. Such challenges include having to systematically conduct laboratory experiments to investigate how the environment affects OMA formation and settling velocities, and the need for a comprehensive algorithm that can estimate an OMA settling velocity.

Operational Modeling of North Aegean Oil Spills Forced by Real-Time Met-Ocean Forecasts

Over the latest decades, oil marine pollution has posed a vital threat for global ocean health, since spillages of any scale are related to environmental, social and financial impacts. The worldwide increase in oil and gas demand, and the parallel rise in oil and gas production, exploiting particularly coastal and offshore marine deposits, have significantly increased the risk of accidental oil release to the sea. In the present study, an operational oil spill model was applied to test the oil dispersive properties and to reveal the relative magnitude of weathering processes, after an accidental oil spill release along the main tanker transportation route in the North Aegean Sea. Numerical simulations were implemented using the OpenOil transport and fate numerical model, a subclass of the OpenDrift open-source trajectory framework. This model integrates algorithms with several physical processes, such as oil entrainment, vertical mixing, oil resurfacing and oil emulsification. The oil dispersion model was coupled to real-time met-ocean forecasts received from NOAA-GFS and CMEMS. Present simulation results have focused on the impact of turbulent kinetic energy, induced by the background flow field, on the horizontal spreading of particles, as well as on the evolution of oil mass balance and oil mass properties.

Surfactant-assisted sol-gel synthesis of zinc ferrite magnetic nanoparticles for oil spills cleanup from seawater and antibacterial activity applications

PurposeThe purpose of this research is to assess the removal of oil spills from the seawater surface as well as the antibacterial activity of ZnFe2O4-cetyltrimethylammonium bromide (CTAB, cationic surfactant) magnetic nanoparticles (ZFO-CTAB MNPs).Design/methodology/approachA CTAB-assisted sol–gel method was used to synthesize ZFO-CTAB MNPs. X-ray powder diffraction and Fourier transform infrared spectroscopy were used for ZFO-CTAB MNPs characterization. Also, the magnetic force and apparent density of ZFO-CTAB MNPs were determined. The oil spill cleanup was investigated by using the gravimetric oil removal (GOR) technique, which used ZFO-CTAB MNPs as oil absorbent material and four oil samples (crude, diesel, gasoline and used oil) as oil spill models. The antibacterial activity of ZFO-CTAB MNPs against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi) was investigated by using the optical density method.FindingsThe results revealed that, when the amount of ZFO-CTAB was 0.01 g, gasoline oil had the highest GOR (51.80 ± 0.88 g/g) and crude oil had the lowest (11.29 ± 0.82 g/g). Furthermore, for Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa, ZFO-CTAB MNPs inhibited bacterial growth with a higher percentage (94.24%–95.63%).Originality/valueThe applications of ZFO-CTAB MNPs in the cleanup of oil spills from aqueous solutions, as well as their antibacterial activity. The results showed that ZFO-CTAB MNPs are a promising material for removing oil spills from bodies of water as well as an antibacterial agent against Gram-negative bacterial strains.

Impact of oil−sediment interaction on transport of underwater spilled oil in the Bohai Sea

Based on a validated underwater oil spill model and validated ocean hydrodynamic background, the influence of oil−sediment interaction on the transport of underwater spilled oil is investigated through numerical experiments. Numerical result shows that interaction between oil and suspended sediment can form oil−sediment aggregates (OSAs), which can significantly decrease the amount of surface oil and increase the amount of underwater oil and its sweeping volume under certain conditions. Sensitivity of the model output (in terms of oil in OSAs, underwater oil amount, surface oil amount, and sweeping volume) to input factors (including oil spill volume, sediment diameter, and sediment concentration) is further investigated quantitatively through numerical experiments, which shows that increasing oil spill volume and sediment concentration and reducing sediment diameter can promote oil−sediment interaction. Among the three input factors, oil spill volume is the most sensitive factor, followed by sediment concentration and sediment diameter. This study is expected to provide useful information for spilled oil monitoring, contingency planning, and environmental damage assessment.

Research on transport and weathering of oil spills in Jiaozhou Bight, China

Jiaozhou Bight is a semi-closed embayment, located on the eastern coast of Jiaodong Peninsula. Qingdao Port located in the bight is one of the largest transportation trade and professional crude oil transportation ports in China. Potential oil spills will cause serious damage to the local ecological environment and lead to huge social and economic losses. In this study, the hydrodynamic model of Jiaozhou Bight was established and its accuracy was verified based on the tidal current data of Qingdao Port and Huangdao Station. The oil spill model of Jiaozhou Bight was constructed by coupling with wind, tidal current and other environmental fields. Taking the “11.22” Huangdao oil spill accident as a case, the accuracy of the developed oil spill model was verified. The key factors affecting oil spill movement in Jiaozhou Bight are found out and the influences of wind regime, tidal current, oil spill source location and oil spill amount on drift and diffusion movement are researched. The effects of wind speed and other factors on weathering of the oil spill are studied. The research results can provide technological supports for making emergency responses to the oil spill in Jiaozhou Bight.

Mathematical modelling of oil spill weathering processes for contingency planning in Izmit Bay

One of the main oil refineries in Turkey is located in Izmit. This results in a high volume of crude oil and oil products handled in Izmit ports. The region is consequently at a very high risk for oil pollution. Due to the destructive effects of oil on the various segments of the environment, comprehensive preventive measures for crisis management related to potential oil spill scenarios are necessary to minimize the contaminated areas. In this study, hydrodynamic data are obtained from the HYDROTAM3D, and 36 oil spill scenarios, which involve Basrah light, Iranian light, and Russian oil, are evaluated for oil spill weathering processes using ADIOS2. Although the API gravities of the three different oil types are within the same range, their weathering processes are noticeably different in terms of their viscosity and density. Moreover, Basrah light oil has a higher evaporation and viscosity increase rate compared to the other two types of oil. Of the three types of oil, the Basrah light is the most likely to hinder recovery actions. In situations of crisis management to provide efficient recovery actions, comparison of weathering modelling data for each handled oil type is necessary for oil spill contingency planning.

Performance Measures for Validation of Oil Spill Dispersion Models Based on Satellite and Coastal Data

This article presents a set of performance metrics, whose purpose is to provide a quantitative measure of the ability of oil spill dispersion models to simulate real-world oil spills. The metrics are described in detail and are applied to the output from an existing oil spill model for two specific case studies. The metrics in question make use of both satellite imagery and coastal impact reports as the basis of the validation. Specifically, we recommend the 2-D measure of effectiveness as a means of quantifying model performance based on the extent of overlap between the observations and the model output. Additionally, we show that it is advantageous to supplement the 2-D measure of effectiveness with a newly proposed set of skill scores, based on the geometric area and centroid of a given oil spill. We also demonstrate how the metrics can be used to assess the sensitivity of a model to its input parameters and the impact this has on the accuracy of the resultant forecast. Finally, we offer a real-world interpretation for each metric introduced and suggest ways that they can be used to assist in cleanup operations of actual oil spills.

Enhancing science-policy interface in marine environmental governance: Oil spill response models as boundary objects in the Gulf of Finland, Baltic Sea

Scientific models provide important input to the governance of complex socio-ecological risks. However, scientific knowledge rarely translates to policy in a simple, direct manner. By focusing on the use of scientific models for oil spill risk assessment and management in the Gulf of Finland (GoF), Baltic Sea, this paper aims to enhance the understanding of the capacity of scientific models to connect science, operational decision-making, and policy. In this study, we conceptualize scientific models as boundary objects, i.e. tools that facilitate interactions between different actors, types of knowledge, and perspectives across system boundaries. The study focuses on the different affordances associated with the models regarding their ability to represent, share, and convey knowledge between science and policy and to link the involved knowledge to action (i.e. changes in practice and in policy). We explore 1) how do the different oil spill models work as boundary objects in the science-policy interface, 2) how do different science-policy contexts affect the model affordances, and vice versa. We also provide recommendations for future research. The study is based on interviews of modelers/researchers, response operators, and policymakers. The results suggest that the existing models lack several of the important affordances that are required to successfully integrate different types of knowledge and transform new knowledge to action. As such, we suggest that currently models remain as instrumental, calculative, tools that support pre-determined policies rather than as means for exploring alternative framings of risks and the possible solutions. Finally, we argue that the co-production of knowledge best supports the plurality of model affordances needed to enable transformative change in policy and practice.

A case study of the Suez Gulf: Modelling of the oil spill behavior in the marine environment

The marine environment is a dynamic and diversified network of habitats and species. The more oil explorations occur in the marine environment, the more strategies of preparedness and response to oil spills should be designed.Once the oil is introduced to the marine environment, it undergoes a series of natural processes known as 'weathering.' For a successful response operations and protection, it is critical to precisely estimate the behavior of the spilled oil.Twenty-four simulated scenarios were created (12 Regular and 12 Worst Cases Scenarios) and run into the licensed Canadian SL-Ross predictive mathematical oil spill model, which successfully was used as a decision support and response tool to investigate the oil spill trajectory, beaching of oil, and its fate from the expected oil drilling rig source near Ras Gharib area in the Red Sea Region.Twenty-four oil spill trajectories maps were developed, which predicted all possibilities and probabilities of oil spill movements. Accordingly, the oil spill trajectories varied not only in magnitude and directions, but also in the shoreline interaction time (hrs.).The weathering processes are shown in ten graphs, which provided output data regarding the change in the spill's total area of slick (km2), the volume of slick (bbl.), the emulsion water content percentage, the rate of evaporation percentage, and the rate of natural dispersion percentage.

Numerical Modelling of Oil Spill Transport in Tide-Dominated Estuaries: A Case Study of Humber Estuary, UK

Oil spills in estuaries are less studied and less understood than their oceanic counterparts. To address this gap, we present a detailed analysis of estuarine oil spill transport. We develop and analyse a range of simulations for the Humber Estuary, using a coupled hydrodynamic and oil spill model. The models were driven by river discharge at the river boundaries and tidal height data at the offshore boundary. Satisfactory model performance was obtained for both model calibration and validation. Some novel findings were made: (a) there is a statistically significant (p < 0.05) difference in the influence of hydrodynamic conditions (tidal range, stage and river discharge) on oil slick transport; and (b) because of seasonal variation in river discharge, winter slicks released at high water did not exhibit any upstream displacement over repeated tidal cycles, while summer slicks travelled upstream into the estuary over repeated tidal cycles. The implications of these findings for operational oil spill response are: (i) the need to take cognisance of time of oil release within a tidal cycle; and (ii) the need to understand how the interaction of river discharge and tidal range influences oil slick dynamics, as this will aid responders in assessing the likely oil trajectories.

Experimental Investigation of Oil Droplet Size Distribution in Underwater Oil and Oil-Air Jet

Abstract Understanding the droplet size distribution of subsea oil releasing is important to predict the subsequent transport and degradation of the spilled oil. Single- and multi-phase oil jet experiments were conducted in the Ohmsett facility, including pure oil jet and oil-air jet through a 10.7-mm pipe and a 4.7-mm pipe. Measurements of the vertical jet hydrodynamics and the oil size distribution were obtained. The reported results help to extend subsea oil spills experiment scale into a meso-scale, and the measurement range of the oil size is widened up to 2 cm. Moreover, the application of dispersant and involvement of air phase provided valuable scientific evidence for the usage of dispersants to treat oil spills. The data confirmed the effectiveness of the dispersant that reduces oil droplet size and also suggested that the participation of the gas phase facilitated the decreasing of oil droplet size. The results were compared to the numerical simulation tool VDROP-J. While the hydrodynamics showed good consistency, the system-dependent coefficient needed a slight revision to coincide with presented data. This also confirmed the significance of experimental materials for further validation and development of oil spill models, where we also provided guidance and discussion on conducting and post-processing the oil spill experiment.

Hazard assessment of oil spills along the main shipping lane in the Red Sea

This study investigates the risk from oil spills along the main shipping lane in the Red Sea based upon oil spill model trajectories forced by the outputs of validated high resolution regional met-ocean data. Following the intra-annual variations in the met-ocean conditions, the results are presented by classifying the basin into three regions: northern, central and southern Red Sea. The maximum distance traveled by the slick is presented for 1, 2, 5, 10, 14 and 20 days after the commencement of a spill. Different measures of hazard assessment in terms of the concentration of beached oil alongside the corresponding probability maps are also analyzed. The volume fractions of beached, dispersed and evaporated oil, 20 days after the commencement of a spill are quantified. The Red Sea general circulation is characterized by rich mesoscale eddies, which appear to be the most prevailing dynamics in oil transport in the basin. Two case events are analyzed to closely examine the effects of the mesoscale circulations on the fate of spilled oil. The results of this study provide a comprehensive assessment of oil spill hazards in the Red Sea, stemming its main shipping lane and identifies the areas at high risk that require timely mitigation strategies.

Stochastic oil spill modeling for environmental protection at the Port of Taranto (southern Italy)

We performed stochastic simulations of hypothetical oil spills from a single-point buoy mooring and subsea pipeline for the Port of Taranto given that this port is an essential strategic hub in the European logistic chain. Our methodology integrates (1) the MEDSLIK-II oil spill model coupled to a high-resolution hydrodynamic model run on an unstructured grid in operational forecasting mode; (2) a hypothetical oil spill scenario based on a historical pipeline rupture at the Port of Genoa, 2016; and (3) randomly sampling the environmental conditions over 2018–2020. The main oil drift was found to be directed southwesterly towards the outlet to the open sea. When oil is transported by highly variable currents, waves and turbulent mixing, it is exposed to multiple strandings and washing-offs from concrete constructions in the port. Consequently, oil tends to be dispersed almost isotropically over the Mar Grande, indicating low to moderate pollution indices.

Impact of ocean waves on transport of underwater spilled oil in the Bohai Sea

To investigate the impact of ocean waves on transport of underwater spilled oil, a wave action module is developed and embedded into an underwater oil spill model. Combined with a validated hydrodynamic background data, the model is applied to a short-term numerical simulation of the 2011 Penglai 19-3 oil spill event in the Bohai Sea. Numerical result shows that the model result is rationally consistent with the field observation. In addition, waves can influence surface oil slick in both horizontal and vertical directions: in horizontal direction, Stokes drift tends to make oil slick spread more widely under the action of wind-waves; in vertical direction, breaking waves tend to entrain the surface oil into water column, and then affects the vertical distribution of spilled oil. Furthermore, sensitivity study shows that using different parameterizations of wave entrainment can make some difference to the model output, but the effect is limited. Besides, the impact of input wave errors varies on different model outputs. This study is expected to provide offshore oil spill emergency responders and researchers with useful information on oil spill monitoring, emergency plans and environmental damage assessment.

Oil spill model uncertainty quantification using an atmospheric ensemble

Abstract. We investigate the impact of atmospheric forcing uncertainties on the prediction of the dispersion of pollutants in the marine environment. Ensemble simulations consisting of 50 members were carried out using the ECMWF ensemble prediction system and the oil spill model MEDSLIK-II in the Aegean Sea. A deterministic control run using the unperturbed wind of the ECMWF high-resolution system served as reference for the oil spill prediction. We considered the oil spill rates and duration to be similar to major accidents of the past (e.g., the Prestige case) and we performed simulations for different seasons and oil spill types. Oil spill performance metrics and indices were introduced in the context of probabilistic hazard assessment. Results suggest that oil spill model uncertainties were sensitive to the atmospheric forcing uncertainties, especially to phase differences in the intensity and direction of the wind among members. An oil spill ensemble prediction system based on model uncertainty of the atmospheric forcing, shows great potential for predicting pathways of oil spill transport alongside a deterministic simulation, increasing the reliability of the model prediction and providing important information for the control and mitigation strategies in the event of an oil spill accident.

Assessing the coastal sensitivity to oil spills from the perspective of ecosystem services: A case study for Canada's pacific coast

Coastal environment is one of the most important ecological and socioeconomic areas. However, increasing energy demand and economic development lead to a continuous gas and oil exploration, production, and traffics, which notably raise the risk of oil spill accidents in coastal areas. Sensitivity assessment aiming to determine the coastal features that would be severely impaired by spill incidents is a crucial part of the response planning. In this study, an innovative framework for coastal sensitivity mapping that incorporated ecosystem service (ES) valuation and multidimensional assessment was proposed. Sensitivity was computed by valuing physical, biological, and social-economical indicators from ES perspective and separating each indicator into specific coastal domains. For different ES typologies, provisioning services contributed most to the overall ES value followed by culture services, supporting services, and regulating services. For ES value in different coastal domains, the highest value was recorded in the water column followed by water surface, shoreline, and seabed. However, the shoreline ranked highest regarding the ES value per ha. Sensitivity assessment revealed that sensitive areas differed in different domains, both in distribution and extent. Compared with the scoring method, the ES valuation method showed more coincidence with Ecologically and Biologically Significant Areas (EBSA), representing a more precise and practical approach for sensitivity assessment. A three-dimensional (3D) oil spill model was also applied to generate maps of oil contamination probability in shoreline, water surface, and water column. The obtained results highlighted the significance of incorporating different coastal domains into oil spill responses, and the urgent demand to broaden and deepen our understanding of ecological processes across the vertical coastal zones.

Development of an oil spill model adaptable to exposure and submergence conversion of tidal flats: A case study in the Changjiang Estuary

Through the application of the Water Pollution Emergency Response System (WPERS) in the Changjiang Estuary, it was found that tidal flats significantly affect the trajectory of an oil film, and the deposition of the oil film on tidal flats is remarkable. In this study, the Estuarine Oil Spill Model (EOSM) was developed to simulate the process of the oil film landing on tidal flats. The Lagrangian particle algorithm and oil fate experience algorithms were adopted. An algorithm for generating dynamic shorelines was also involved. Compared to the oil spill algorithm without wet-dry functionality, the spatial distribution of the oil film deposition simulated in the EOSM better matched the reanalysis data of the satellite remote sensing image. This indicated that the dynamic wet-dry switch phenomenon of tidal flats could be involved in the simulation of offshore oil spills to improve the accuracy of accident prediction and ecological loss assessment. Plain language summaryOn December 30th, 2012, a vessel carrying 400 tons of heavy oil sank in the Changjiang Estuary, China. The heavy oil leaked at around 4 am the next day. In this study, a new oil spill model was developed to simulate the process of an oil film landing on land and tidal flats. An algorithm for generating the dynamic shorelines in an oil spill simulation was adapted for the wet-dry switch of tidal flats. The landing distribution of the oil film in this new model was well matched to the satellite image for this accident. This indicated that the dynamic wet-dry switch phenomenon of tidal flats could be involved in the simulation of oil spills offshore, to improve the accuracy of accident prediction and ecological loss assessment. The research results could provide some new ideas for the development of offshore oil spill simulation technology.

Modelling the accidental oil spills at potentially hazardous facilities in the Arctic zone of Krasnoyarsk Krai

Intensified human activity in exploiting the natural resources leads to increasing technogenic load on Arctic’s fragile ecosystem. The boost in industrial facilities is associated with a growing number of stationary fuel reservoirs poorly monitored due to their considerable remoteness and extreme weather conditions. The 2020 emergency in the Arctic zone of Krasnoyarsk Krai exposed the lack of adequate methods for risk assessment and behaviour in case of accidents at potentially hazardous facilities. The existing methodologies for assessing the area of spill following an accidental depressurisation present significant limitations. Most methodologies are based on analytical models not taking into account the physics of processes. This work uses modelling with neural networks of oil spill at the potentially hazardous object located in the Arctic territory of the Krasnoyarsk Krai. The software used was neural network simulator NeuroPro, developed in the Institute of Computational Modelling of Krasnoyarsk Scientific Centre of SB RAS. For training the neural network there were used daily operational data on fourteen main vectors affecting the propagation rate. The neural network modelling of the accidental oil spill during the depressurization of one of the fuel tanks at potentially hazardous facilities in the Arctic zone in 2020 correlated perfectly with the real data.

A Review of River Oil Spill Modeling

River oil spills are generally more frequent and pose greater environmental and public health risk than coastal and offshore oil spills. However, the river oil spill research has received a negligible amount of academic attention in the past three decades, while at the same time the coastal and offshore oil spill research has expanded and evolved tremendously. This paper provides the state-of-the-art review of river oil spill modeling and summarizes the developments in the field from 1994 to present. The review has revealed that the majority of the gaps in knowledge still remain. Thus, there is a need for (i) experimental studies in order to develop and validate new models and better understand the main physicochemical processes, (ii) studies on inter-linking of the governing processes, such as hydrodynamics, advection–dispersion, and weathering processes, (iii) adaptation and validation of coastal and offshore oil spill models for applications in riverine environments, and (iv) development of river oil spill remote sensing systems and detection techniques. Finally, there is a need to more actively promote the importance of river oil spill research and modeling in the context of environmental and public health protection, which would form the basis for obtaining more research funding and thus more academic attention.