Browsing by Author "Penrose, B"

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    Ecotoxicological effects of decommissioning offshore petroleum infrastructure: a systematic review
    (Taylor & Francis, 2021-05-07) MacIntosh, A; Dafforn, KA; Penrose, B; Chariton, AA; Cresswell, T
    Successful decommissioning of subsea oil and gas infrastructure requires a safe and effective approach to assess and manage waste products. These products, often present as scale on internals of pipelines, include naturally occurring radioactive materials (NORM) and trace metals. Understanding the potential effects of these contaminants on marine fauna is crucial to managing global decommissioning. This review is composed of two aspects: 1) a systematic review was conducted to synthesize literature on all contaminants associated with decommissioned offshore structures and the effects of NORM contaminants on marine organisms; 2) a critical review of current environmental regulations for decommissioning and characterization of petroleum scale and NORM components. Studies defining the chemical and radiological contaminants associated with decommissioned structures were very limited. The main source of contaminants was identified from offshore platforms, with none from subsea structures. Only three studies measured variable chemical effects of radium to organisms from scale materials in subsea oil and gas infrastructure. No studies measured effects on organisms from other NORM, such as lead-210 and polonium-210. Currently, there are no international regulations on subsea pipeline closure, with NORM being underreported and not addressed in environmental impact assessments. This review highlights research gaps from environmental monitoring and characterization of NORM associated with decommissioned structures. Key recommendations for future research include characterizing NORM scale and assessing effects of scale to marine organisms through direct organism exposure experiments. This review emphasizes the need to incorporate ecotoxicology into environmental risk assessment for offshore petroleum decommissioning. © 2021 The Author(s). Published with license by Taylor & Francis Group, LLC.
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    Radiological risk assessment to marine biota from exposure to NORM from a decommissioned offshore oil and gas pipeline
    (Elsevier Ltd, 2022-08-11) MacIntosh, A; Koppel, DJ; Johansen, MP; Beresford, NA; Copplestone, D; Penrose, B; Cresswell, T
    Scale residues can accumulate on the interior surfaces of subsea petroleum pipes and may incorporate naturally occurring radioactive materials (NORM). The persistent nature of ‘NORM scale’ may result in a radiological dose to the organisms living on or near intact pipelines. Following a scenario of in-situ decommissioning of a subsea pipelinNe, marine organisms occupying the exteriors or interiors of petroleum structures may have close contact with the scale or other NORM-associated contaminated substances and suffer subsequent radiological effects. This case study used radiological dose modelling software, including the ERICA Tool (v2.0), MicroShield® Pro and mathematical equations, to estimate the likely radiological doses and risks of effects from NORM-contaminated scale to marine biota from a decommissioned offshore oil and gas pipeline. Using activity concentrations of NORM (226Ra, 210Po, 210Pb, 228Ra, 228Th) from a subsea pipeline from Australia, environmental realistic exposure scenarios including radiological exposures from both an intact pipe (external only; accounting for radiation shielding by a cylindrical carbon steel pipe) and a decommissioned pipeline with corrosive breakthrough (resulting in both internal and external radiological exposure) were simulated to estimate doses to model marine organisms. Predicted dose rates for both the external only exposure (ranging from 26 μGy/h to 33 μGy/h) and a corroded pipeline (ranging from 300 μGy/h to 16,000 μGy/h) exceeded screening levels for radiological doses to environmental receptors. The study highlighted the importance of using scale-specific solubility data (i.e., Kd) values for individual NORM radionuclides for ERICA assessments. This study provides an approach for conducting marine organism dose assessments for NORM-contaminated subsea pipelines and highlights scientific gaps required to undertake risk assessments necessary to inform infrastructure decommissioning planning. © 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
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    To leave or not to leave: a tiered assessment of the impacts of scale residue from decommissioned offshore oil and gas infrastructure in Australia
    (ICRP, 2025-11-06) MacIntosh, A; Cresswell, T; Koppel, DJ; Hirth, GA; Tinker, R; Dafforn, KA; Chariton, AA; Penrose, B; Langendam, AD
    There are a range of potential options for the decommissioning of offshore petroleum infrastructure, including: complete removal; removal of topside infrastructure with subsea infrastructure left in situ; or partial removal or modification of infrastructure. The current decommissioning liability in Australia is estimated to exceed US$40 billion over the next 50 years. This is founded on the base-case regulatory position of complete removal of all infrastructure, with over half the liability occurring in the next 10 years. In Australia, a recently updated decommissioning framework requires that the planning for decommissioning begins from the outset of the project, and plans are matured throughout the life of operations. Successful decommissioning of subsea oil and gas infrastructure requires an effective and safe approach for assessing and managing chemical and radiological residues. Naturally occurring radioactive materials (NORM) are ubiquitous in oil and gas reservoirs around the world and may form contamination products including scales and sludges in topside and subsea infrastructure. In situ decommissioning of infrastructure left in the marine environment has many ecological benefits including establishment of artificial reefs, economic benefits from associated fisheries, reduced costs and improved human safety outcomes. However, there may be ecological risks associated with leaving infrastructures in the marine environment that are not well understood. Following a scenario of in situ decommissioning of subsea petroleum infrastructure, marine organisms occupying the exteriors or interiors of production pipelines may have close contact with the scale (metal and radionuclide contaminants). Consequently, radio- and chemo-toxicological effects from the scale could occur respectively. This paper considers the current assessment process for NORM-contamination products in oil and gas systems, recent and emerging Australian research in marine radioecology. Here we demonstrate a tiered approach to assess the ecological impacts of pipeline scale related to decommissioning practices, and identifies key research priorities. This can further aid our understanding of the fate of NORM contaminates in subsea oil and gas systems and guide Australia-specific (expand to other petroleum operating countries) risk assessments for infrastructure decommissioning options. The creation of a tiered assessment will enable industry to optimise decommissioning solutions and allow regulators to set clearer expectations on the requirements for environmental protection.