A review of the potential risks associated with mercury in subsea oil and gas pipelines in Australia
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Date
2022-11-01
Journal Title
Journal ISSN
Volume Title
Publisher
CSIRO
Abstract
In the coming years, the oil and gas industry will have a significant liability in decommissioning offshore infrastructure such as subsea pipelines. The policies around decommissioning vary depending on regional policies and laws. In Australia, the ‘base case’ for decommissioning is removal of all property and the plugging and abandonment of wells in line with the Offshore Petroleum and Greenhouse Gas Storage (OPGGS) Act 2006. Options other than complete
removal may be considered where the titleholder can demonstrate that the alternative decommissioning activity delivers equal or better environmental outcomes compared to complete removal and meets all requirements under the OPGGS Act and regulations. Recent research has demonstrated that decommissioning in situ can have significant environmental benefits by forming artificial reefs, increasing marine biodiversity, and providing a potential fishery location.
An issue, which has been given less attention, is around contaminants remaining within decommissioned infrastructure and their potential risks to the marine environment. Mercury is a contaminant of concern known to be present in some oil and gas pipelines, but the potential long-term impacts on marine ecosystems are poorly understood. We present a synthesis of information on mercury cycling in the marine environment including key drivers of methylation in
sediments and ocean waters, existing models to predict methylmercury concentrations in sediments, and toxicological effects to marine biota. We discuss the applicability of existing water and sediment quality guidelines, and the associated risk assessment frameworks to decommissioning offshore infrastructure contaminated with mercury. Globally, research is needed to provide a comprehensive risk assessment framework for offshore infrastructure decommissioning. We recommend future areas of research to improve our understanding of the potential risks associated with mercury in subsea oil and gas pipelines. © 2022 The Author(s) (or their employer(s)). This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
Description
Keywords
Decommissioning, Acquatic ecosystems, Mercury, Petroleum, Risk assessment, Sediments, Seas, Pipelines, Australia, Wells
Citation
Gissi, F., Koppel, D., Boyd, A., Kho, F., von Hellfeld, R., Higgins, S., Apte, S., & Cresswell, T. (2022). A review of the potential risks associated with mercury in subsea oil and gas pipelines in Australia. Environmental Chemistry, 19, (4), 210-227. doi:10.1071/EN22048