Use of sorbents for oil spills

It is generally acknowledged that removing spilled oil from the sea is preferable to dispersing it, but there have been severe problems in devising methods of collecting oil from thin slicks. In this article the merits of various methods of absorbing spilled oil are reviewed.     

Marine oil spills: An Australian view

Australia, now experiencing oil spills, is devising a clean-up policy in the light of international experience.     

Consequences of linseed oil spills in salt marsh sediments

In a simulated spill in a salt marsh, linseed oil penetrated rapidly into the sediments at a rate of 10(-7) cm2 s(-1). The oil concentration remained unchanged for the first month after the spill, but 60% of the oil disappeared from the top 30 cm after a further month. The oil adsorbed to and accumulated in the muddy sediments (top 15 cm) leading to decreased sediment permeability, pH, Eh, abundance of plant roots and infauna and to the establishment of anoxic conditions. These changes accompanied transformations in the original fatty acid composition of the linseed oil, mainly associated with a decrease in 18 : 3omega3, an increase in the other fatty acids and the presence of 'new' fatty acids. A rapid increase in the abundance of heterotrophic aerobic and anaerobic bacteria and aerobic oil degrading bacteria, suggested that these micro-organisms degraded the oil. The role of the bacteria in oil degradation was confirmed in laboratory experiments where the fatty acids composition of the linseed oil underwent identical transformations to those obtained in the field. The degradation of linseed oil appears to be a sequential process initiated by aerobic and/or anaerobic bacteria and continued by sulphate reducing bacteria, which were unable to degrade the raw oil.     

Effect of non-petroleum oil spills on wintering birds near Vancouver

Within the period of our records, spills of vegetable oils at Vancouver harbour have caused greater losses of birds than spills of petroleum oils. Vegetable oils affect birds by feather wetting but do not exhibit odour and slick characteristics of petroleum oils. Because most vegetable oils are edible their potential danger to aquatic birds may go unnoticed; sites of storage and transhipment of vegetable oils may be overlooked in oil spill contingency planning.     

Compensation for oil pollution damage caused by oil spills from ships and the international oil pollution compensation fund

Liability and compensation for pollution damage caused by oil spills from laden tankers is governed by two international conventions: the 1969 Civil Liability Convention and the 1971 Fund Convention. The Civil Liability Convention established a system of strict liability for tanker owners and introduced compulsory liability insurance. The Fund Convention created a system of supplementary compensation administered by an intergovernmental organization, the International Oil Pollution Compensation Fund (IOPC Fund), which at present has 56 member states (August 1993). The IOPC Fund pays compensation to victims of oil pollution in member states when the compensation from the shipowner and his insurer is insufficient. Over the years (up to August 1993), the IOPC Fund has been involved in 66 incidents and has paid US$92 million to victims. Only three of these incidents have been taken to court, whereas in all other cases claims have been settled out of court. The IOPC Fund has developed a policy on the admissibility of claims covering clean-up costs, measures to prevent pollution, damage to property and economic loss suffered by fishermen, hotel-owners and others who depend directly for their livelihood on sea-related activities.     

Simulated oil spills at two offshore fields in the Arabian gulf

A computer simulation program of oil spills in the Arabian Gulf, GULFSLIK II, is developed and applied to two offshore fields. The results of the simulation are examined to ascertain the risks to the neighboring coastal areas.     

Extent and frequency of vessel oil spills in US marine protected areas

Little is known about how marine protected areas (MPAs) may be vulnerable to vessel oil spills in the United States. This study investigated individual size, frequency, and total amount of vessel oil spilled in US MPAs, and how characteristics of MPAs and individual spill events influenced spills. Vessel oil spills in US waters (2002-06) and MPA boundaries were mapped. Total number and volume of oil spills inside and outside MPAs were computed. Results show that the presence of a MPA does not seem to prevent vessel oil spills or reduce the amount of oil spilled, and that a variety of MPA attributes (e.g., scale of protection, fishing restrictions, and others) and spill event characteristics (e.g., vessel type, year of spill, and others) affect oil spills inside and outside MPAs. These results can be used to develop MPA rules and marine transportation policies that reduce the vulnerability of sensitive resources to oil spills.     

Experimental investigation of various vegetable fibers as sorbent materials for oil spills

Oil spills are a global concern due to their environmental and economical impact. Various commercial systems have been developed to control these spills, including the use of fibers as sorbents. This research investigates the use of various vegetable fibers, namely mixed leaves residues, mixed sawdust, sisal (Agave sisalana), coir fiber (Cocos nucifera), sponge-gourd (Luffa cylindrica) and silk-floss as sorbent materials of crude oil. Sorption tests with crude oil were conducted in deionized and marine water media, with and without agitation. Water uptake by the fibers was investigated by tests in dry conditions and distillation of the impregnated sorbent. The silk-floss fiber showed a very high degree of hydrophobicity and oil sorption capacity of approximately 85goil/g sorbent (in 24hours). Specific gravity measurements and buoyancy tests were also used to evaluate the suitability of these fibers for the intended application.     

Probabilistic analysis of risk and mitigation of deepwater well blowouts and oil spills

The development of robust risk assessment procedures for offshore oil and gas operations is a major element for the assessment of the potential feedback between planned activities and the environment. We illustrate a methodological and computational framework conducive to (1) a quantitative risk analysis of deepwater well barrier failures and subsequent hydrocarbon release to the environment and (2) the analysis of the value of the deployment of conventional and/or innovative mitigation measures. Our methodological framework is grounded on historical records and combines the use of Dynamic Event Trees and Decision Trees from which we estimate probability of occurrence and impact of post-blowout events. Each sequence of response actions, which are undertaken immediately after the event or in the subsequent days, is considered within the context of appropriately structured event paths. This approach is conducive to an estimate of the expected value of key decisions and underlying technologies, with an emphasis on their potential to reduce the oil spill volume, which can critically impact the environment. Our study yields an original comparative analysis of diverse intervention strategies, and forms a basis to guiding future efforts towards the development and deployment of technologies and operating procedures yielding maximum benefit in terms of safety of operations and environmental protection.     

IT-OSRA: applying ensemble simulations to estimate the oil spill risk associated to operational and accidental oil spills

Oil Spill Risk Assessments (OSRAs) are widely employed to support decision making regarding oil spill risks. This article adapts the ISO-compliant OSRA framework developed by Sepp Neves et al. (J Environ Manag 159:158–168, 2015) to estimate risks in a complex scenario where uncertainties related to the meteo-oceanographic conditions, where and how a spill could happen exist and the risk computation methodology is not yet well established (ensemble oil spill modeling). The improved method was applied to the Algarve coast, Portugal. Over 50,000 simulations were performed in 2 ensemble experiments to estimate the risks due to operational and accidental spill scenarios associated with maritime traffic. The level of risk was found to be important for both types of scenarios, with significant seasonal variations due to the the currents and waves variability. Higher frequency variability in the meteo-oceanographic variables were also found to contribute to the level of risk. The ensemble results show that the distribution of oil concentrations found on the coast is not Gaussian, opening up new fields of research on how to deal with oil spill risks and related uncertainties.