Threshold values for the protection of marine ecosystems from NORM in subsea oil and gas infrastructure

Darren J. Koppel* (Corresponding Author), Tom Cresswell, Amy Macintosh, Rebecca von Hellfeld, Astley Hastings, Stuart Higgins

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
8 Downloads (Pure)


Naturally occurring radioactive materials (NORM) may contaminate some oil and gas infrastructure. The risk of these NORM contaminants to the marine ecosystem must be assessed to determine appropriate decommissioning options, particularly where in situ decommissioning options are permitted. This is challenging because in these decommissioning scenarios, contaminants may be isolated from the marine environment until containing infrastructure corrodes, and there are limited data and guidelines describing how to assess radionuclide risk in a manner consistent with international recommendations.
This modelling study uses the ERICA approach to derive threshold values assessing the dose rate from NORM-contaminated products found in subsea oil and gas infrastructure to marine organisms.
Products include unsupported: (1) radium (226Ra and 228Ra) contaminated scales, (2) 210Pb films, and (3) 210Po films. Threshold values are calculated as the activity of the products’ head of chain radionuclide (i.e. 226Ra and 228Ra, 210Pb and 210Po, respectively) that will increase radiation dose rates in sediments by 10 µGy/h to the most exposed organism at a given release time.
To account for temporal variability in radioactivity of NORM-contaminated products due to ingrowth and decay, threshold values were also calculated at different ages of NORM-contaminated products allowing for age-dependent threshold values. The lowest values (corresponding to peak radiation dose rates from the ingrowth of progeny) were for radium-contaminated scales which were 0.009 Bq 226Ra/g, 0.029 Bq/g 228Ra (in the absence of 226Ra) or 0.14 Bq 228Ra/g (in the presence of 226Ra), 0.015 Bq/g for 210Pb films, and 1.6 Bq/g for 210Po films. These may be used as default threshold values and when added to background radionuclide activities after determining appropriate mixing and dilution, can provide a default screening value for generic assessments. Added activities of the NORM contaminated products to marine sediments below these threshold values implies a negligible doserate risk to organisms while exceedances imply that further investigation is necessary.
Original languageEnglish
Article number107093
JournalJournal of environmental radioactivity
Early online date6 Jan 2023
Publication statusPublished - Mar 2023

Bibliographical note

The authors thank Professor Claus Otto (Curtin University) and Professor Richard Neilson (National Decommissioning Centre, Aberdeen, UK.) for comments and support to the project team; and, Sam Jarvis (National Environment Resources Australia), Professor Peter Macreadie, Dr Rick Tinker, and the industry partners of the National Decommissioning Research Initiative for helpful comments to
this project.
This research was funded by the Australian Government’s Industry Growth Centre National Energy Resources Australia (NERA) through a National Decommissioning Research Initiative (NDRI) grant to Curtin University. The NDRI project was funded by eight industry partners including Shell Australia,
Esso Australia, Chevron Australia, BHP Petroleum, Woodside Energy, Santos Limited, ConocoPhillips Pipeline Australia, and Vermilion Oil and Gas Australia. AH is partly funded by the National Decommissioning Centre, Scotland, and the University of Aberdeen.

Data Availability Statement

No data was used for the research described in the article.


  • risk assessment
  • Rigs to reef
  • decommissioning
  • radium


Dive into the research topics of 'Threshold values for the protection of marine ecosystems from NORM in subsea oil and gas infrastructure'. Together they form a unique fingerprint.

Cite this