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Environmental and Scientific Issues

Oil Spill Trajectory Modelling

AMSA has recently updated its web site with two important new documents.

To assist National Plan stakeholders to understand the Oil Spill Trajectory Model (OSTM), the Top 30 Questions about the spill model have been answered on the web. This web page provides an overview of the recent changes and upgrades to OSTM, how the system operates, the range of datasets used, what types of outputs can be provided and examples of its use in spill incidents.

Additionally a revised form for requests for OSTM outputs for spill incidents and exercises has been added to the website. The new electronic form can be completed on-line and sent via email to AMSA. Faxed requests of the paper forms can still be sent through to 02 6279 5076.

Both web pages can be accessed under the National Plan, General Information pages at www.amsa.gov.au

Oil Spill Response Atlas

The Oil Spill Response Atlas (OSRA) provides vital environmental, biological and logistical information to marine spill responders in a useful and effective format to enable a fast and efficient response to oil and chemical spills in the marine environment.

A total of $112,500 was spent during the 2004-2005 financial year on State and Northern Territory OSRA Tasks. Funding for the 2005-2006 financial year has been approved to a sum of $82,000. This has been reduced due to competing budgetary priorities including the Chemical Spill Risk Assessment.

The Environment Working Group identified to NPOG 9 in November 2004 that it was timely to migrate OSRA and the OSRA Toolset to the ArcGIS platform; as such, NPOG decided to allocate $50,000 towards the migration. The project will take place during the financial year 2005-2006.

Research, Development and Technology Program

Bunker Weathering and Fingerprinting Study

When investigating and prosecuting ‘mystery spills’ where the source of the spill is unknown, authorities need to be able to determine how long the spilt oil has been at sea. Recent court cases in Australia have raised concerns regarding a lack of fundamental data on the rate and timing of bunker fuel oil weathering at sea. Because weathering of the oil changes its chemical properties, chromatographic profiles for weathered oils can look very different to profiles for fresh oil samples from ships.

To address the identified lack of data, funding was allocated from the National Plan and a consultant engaged to carry out a research project on the effects of weathering at sea of various grades of bunker oils.

The research project was commenced and completed during 2004-2005. The results of this successful project have provided an improved understanding of marine bunker fuel properties, behaviour, variability and weathering. The study has also demonstrated the effectiveness of the oil spill fingerprinting techniques employed by local analytical testing laboratories for National Plan oil spill investigations.

The final report has been circulated to National Plan stakeholders and a summary is available on the AMSA website.

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Oil and Dispersed Oil Impacts on Temperate Seagrasses

Although Australian-approved Oil Spill Dispersants rate predominantly as "slightly toxic" to "practically non-toxic" by the International Maritime Organization GESAMP classification system, there is limited knowledge on the specific effects on seagrasses exposed to dispersants. The use of dispersants may also increase the exposure of submerged seagrasses to oil as dispersed oil enters the water column.

To address the knowledge gap on the impact on seagrasses exposed to oil spills, AMSA entered into a funding agreement on behalf of the National Plan with the University of Technology Sydney (UTS). The National Plan is also providing in-kind support and technical advice to the research team.

The UTS researchers are using a combination of laboratory and field experiments to compare the toxicity of several oils and dispersant/oil mixtures on seagrasses, and to provide advice on the best approach to the use of dispersants on oil spills in the vicinity of seagrasses. An additional aim is the development of a method using microalgae to provide a rapid bioassay of expected impacts on seagrass from oils and oil/dispersant mixtures.

During 2004-2005, UTS completed proof-of-concept work using Slickgone NS and Gippsland Crude oil to study effects on a common seagrass species in temperate waters in New South Wales (Zostera capricorni). Subject to the approval of NPOG, the report on this work will be circulated in late 2005.

UTS and the Australian Research Council have provided further funding towards the project. Over the next three years, a PhD student will continue the work with more dispersants and oils. The National Plan will provide in-kind support and technical advice via the Environment Working Group throughout the project.

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Updated: May 2006