|Abstract Title:||Mercury methylation in the marine environment and potential risks associated with subsea oil and gas pipelines|
|Presenter Name:||Francesca Gissi|
|Session:||Special Session - Mercury in the Southern Hemisphere|
|Day and Session:||Wednesday 27th July - Session One|
|Start Time:||06:30 UTC|
|Co-Authors:||Francesca Gissi,Alexandra Boyd,Simon Apte,Chad Jarolimek,Fenny Kho,Darren Koppel,Rebecca von Hellfeldd,Stuart Higgings,Tom Cresswell|
Abstract Information :
In 2015-2016, Australias marine industries were worth an estimated AUD$68 billion annually, with the second largest contributor being the oil and gas industry (AUD$23 billion annually). It is estimated that by2026, over 65 offshore oil and gas installations will require decommissioning in some form. Current legislative requirements in Australia stipulate complete removal of all offshore infrastructure by the operator post-production life. This is a AUD$53 billion liability with subsea pipelines accounting for a third of the total decommissioning cost. There is an opportunity for some assets to be left in place under certain circumstances when deemed environmentally acceptable. This may have benefits for the marine ecosystem, where biomass of commercially important fisheries species can be up to 3.5 times greater on artificial structures than on surrounding natural reefs. However, there is rarely any recognition of contaminants associated with subsea pipelines that may contain metals (e.g. mercury) in the form of precipitated scale or films on production pipeline internal surfaces. Contaminants may leach from infrastructure over time if decommissioned in situ, which may impact marine organisms around decommissioned pipelines and potential human consumers (i.e. via fisheries).
Unique radiotracing capabilities at Australia?s Nuclear Science and Technology Organisation (ANSTO) allow us to understand the transport, uptake, and depuration pathways of contaminants in marine biota. The development and production of mercury radioisotopes (Hg-203) at ANSTO has led to the application of this radiotracer to a diverse range of research fields from human health to the environment. This paper will present experimental plans to apply the radiotracer to environmental studies to understand conditions which promote mercury methylation in the marine environment. Our research will inform investigations into the potential risk of mercury associated with decommissioning subsea oil and gas pipelines.