Executive Summary
Society’s need for energy, industrial processes, health and wellbeing and national security have resulted in past and present human activities that have led to the introduction of radionuclides to the marine environment. Activities linked to the production of energy (nuclear sector) have led to discharges of artificial radionuclides, while extraction of oil and gas activities have resulted in the discharge of naturally occurring radionuclides. Industrial uses, research, survey and educational activities and medical uses have also led to discharges of radionuclides. Military activities such as atmospheric nuclear weapons testing and other sources such as the Chernobyl accident have resulted in further inputs of radionuclides to the marine environment.
Under the Radioactive Substances Strategy (RSS) of the North-East Atlantic Environment Strategy (NEAES) 2010-2020, OSPAR’s aim was to reduce inputs and levels of radionuclides. From the assessments carried out by OSPAR on data available up to 2018, there is clear evidence for the nuclear sector of progressive and substantial reductions in discharges in the majority of cases. For the oil and gas sub-sector there is evidence of some reductions in discharges. However, in most cases discharges of radioactive substances from this sub-sector have remained unchanged. As to indicator radionuclides for the nuclear sector, there is clear evidence that current environmental concentrations are close to or lower than historic levels. The environmental concentrations of indicator radionuclides for the nuclear sector and modelled additional concentrations of indicator radionuclides for the oil and gas sub-sector would not result in a significant radiological impact on humans or the marine environment.
It can be concluded that Contracting Parties have successfully fulfilled the objectives of the OSPAR RSS for 2020 under the NEAES 2010-2020 and have made significant progress towards fulfilling the ultimate aim of concentrations in the environment near background values for naturally occurring radioactive substances and close to zero for artificial radioactive substances. In doing so, Contracting Parties have prevented pollution of the OSPAR Maritime Area by ionising radiation. As delivering the aims of the OSPAR Convention is an ongoing task, new strategic and operational objectives for radioactive substances have been agreed by OSPAR under the new NEAES 2030.
Q1. Identify the problems? Are they the same in all OSPAR Regions?
Radioactive substances affect living organisms
Radioactivity is associated with energy released from radionuclides through radiation. Ionising radiation occurs as electromagnetic rays (γ-rays), α-particles and β-particles. It can cause genetic, reproductive, cancerous as well as acute effects in living organisms. Because of this, it has the potential to cause negative effects on marine organisms at the level of populations and to affect human health through, for example, seafood consumption. The potential for harm through radiation depends on the properties of the radionuclides, the amount of radiation energy absorbed by marine organisms (i.e. the dose) and the pathway through which they are exposed.
Impact across the OSPAR Regions
As was the case for the Quality Status Report (QSR) 2010, the main sources from which radioactive substances are discharged into the OSPAR Maritime Area are the nuclear sector (associated with electricity generation) and the non-nuclear sector (mainly the offshore oil and gas industry). The contribution to environmental concentrations from liquid discharges of radioactive substances from the nuclear and non-nuclear sectors is greatest within the area where discharges occur. The majority of discharges of radioactive substances from the nuclear and non-nuclear sectors occur in OSPAR Regions II (Greater North Sea) and III (Celtic Seas). Discharges of radioactive substances can be transported away from discharge points by ocean currents to other parts of the OSPAR Maritime Area, where environmental concentrations are typically lower than in the areas where the discharges originated. However, in some cases marine biota have the ability to accumulate levels of radionuclides to a relatively high degree, even if environmental concentrations in seawater are low.
The nuclear sector is the main source of artificial radionuclides
The number of nuclear sector sites in OSPAR countries discharging radionuclides directly or indirectly to the OSPAR Maritime Area has decreased in the past ten years. In 2021, the 82 nuclear sites (Figure 1) in operation or undergoing decommissioning in the OSPAR catchment area comprised: nuclear power plants, which harness the heat produced in nuclear reactions and convert this to electrical energy; nuclear fuel reprocessing plants, which recycle used nuclear fuel to recover uranium and plutonium; nuclear fuel fabrication and enrichment plants, which provide the uranium fuel for the power plants; and research and development facilities relating to all aspects of the nuclear sector and which can include the production of radionuclides for medical or industrial purposes.
Discharges from the nuclear fuel reprocessing sub-sector remain the dominant source of discharges from the nuclear sector, although they are lower than during the period 1995 to 2001. In the period 2012 to 2018, this sub-sector contributed 92% of total alpha discharges and 67% of total beta (excluding tritium) discharges from the nuclear sector. The radionuclides used as indicators of discharges from the nuclear sector are caesium 137 (Cs-137), technetium-99 (Tc-99), plutonium-239,240 (Pu-239,240) and tritium (H-3). OSPAR has recognised that the industrial-scale abatement of tritium in the liquid effluent of nuclear power stations and nuclear reprocessing facilities is currently not technically feasible. Therefore, discharges of tritium are not currently assessed but discharge data for tritium is reported to OSPAR.
Figure 1: Nuclear sites for which discharges were reported by Contracting Parties to OSPAR in the period 1995 to 2018. The status of these sites may have changed from operational to decommissioning during the reporting period.
Offshore oil and gas activities discharge naturally occurring radionuclides
The offshore oil and gas industry is the largest non-nuclear contributor to the discharges of radioactive substances to the marine environment. Almost all the radionuclides discharged from this sector are from produced water (water extracted from the reservoir with the oil and gas) with smaller contributions from the descaling of pipes. The naturally occurring radionuclides in produced water include lead-210 (Pb-210), polonium-210 (Po-210), and radium-226 (Ra-226) and radium-228 (Ra-228). A less important source is the use of radioactive substances (e.g. tritium) as tracers.
Other non-nuclear sources are minor
An increasing number of radionuclides are used in medicine for therapy and diagnosis. The half-life1 (the time taken for the radioactivity of a specified isotope to fall to half its original value) of the large majority of these radionuclides is so short (usually less than one day) that they do not reach the marine environment after they are discharged. The main source of radioactive discharges from the medical sector to the marine environment is from the use of radioactive iodine-131 (I-131) in the treatment of thyroid complaints. However, the combination of the relatively short half-life of I-131 (eight days) and the use of delay tanks and discharge routes via municipal sewers, means that far lower levels reach the marine environment than are administered to patients. Several Contracting Parties report data to OSPAR for a number of other non-nuclear sub-sectors. From the data that have been reported for the university and research centre sub-sector, it is reasonable to conclude that this sub-sector is not a significant contributor to tritium or total beta (excluding tritium) discharges and that there are no alpha discharges. Radiochemical production is carried out in several Contracting Parties, but the discharges from this sub-sector are in some cases included with those from the nuclear research and development sub-sector due to co-location of sites. Discharges of naturally occurring radionuclides have been reported by some Contracting Parties for phosphate production, titanium dioxide pigment manufacture, primary steel manufacture and rare earth mineral production. From the data that have been reported to OSPAR it is reasonable to conclude that these sub-sectors are no longer a significant contributor to total alpha and total beta (excluding tritium) discharges.
Other sources of radionuclides to the marine environment
It is important to note that not all radionuclides present in the North-East Atlantic marine environment are the result of authorised discharges from the nuclear and non-nuclear sectors. There have been a number of accidents and events, such as the Chernobyl accident in 1986 and fallout from atmospheric nuclear weapons testing in the 1950s and 1960s, which have resulted in the introduction of radionuclides to the marine environment. Other industrial activities have also released radionuclides into the marine environment as a consequence of their processes. In many cases, the additional sources of radionuclides from these historical accidents and events are still detectable today and will generally be indistinguishable from past and contemporary discharges of radionuclides. For this reason, monitoring data for environmental concentrations of radioactive substances reflect the sum of contributions from historical accidents and events and past and contemporary discharges of radionuclides. In addition, environmental concentrations of naturally occurring radionuclides by definition will also contain natural background levels of these radionuclides.
Future developments
A number of the nuclear power stations and other nuclear facilities that have been in operation over the last decades are now either decommissioned or will be decommissioned over the next decade. Although operational discharges from these facilities will cease, discharges associated with decommissioning will continue for a period of time during which there could be some fluctuations in the amount of radioactive substances discharged from year to year. Currently, there are two new civilian nuclear power stations under construction that will contribute additional discharges to the OSPAR Maritime Area, but other projects are under discussion. In addition, some Contracting Parties are examining the possible construction and use of small modular reactors as an alternative model for energy production to the larger scale nuclear power stations in use today.
For the oil and gas sub-sector, the current trend of declining production and associated produced water volumes as well as increasing decommissioning activities would be expected to continue.
Q2. What has been done?
Use of Best Available Techniques to reduce radioactive discharges
OSPAR’s work to prevent and reduce pollution from radioactive substances has focused on the nuclear sector and the application of Best Available Techniques (BAT). Examples of BAT for the nuclear sector include treatment systems for converting radionuclides in effluents into solid waste for disposal. Even when BAT is applied, low-level radioactive discharges into the environment are usually unavoidable. Such discharges are regulated through authorisations from the authorities. Regular reports to OSPAR indicate that the use of BAT is stipulated in national legislations and regulations and that management systems are in place to minimise radioactive discharges from the nuclear sector to the extent possible. OSPAR Contracting Parties also use BAT to prevent pollution from oil and ‘other substances’ caused by discharges of produced water, and this can also result in reduced discharges of naturally occurring radionuclides.
Monitoring programmes and assessment methodologies developed
OSPAR has established common tools and methods for monitoring and reporting discharges from the nuclear and non-nuclear sectors as well as environmental concentrations. Baselines have been established against which progress in reducing discharges and environmental concentrations can be monitored. Statistical methods to evaluate progress have also been identified. An approach for modelling additional concentrations of indicator radionuclides from discharges of produced water from the oil and gas sub-sector has been developed. OSPAR has also agreed a methodology to assess the radiological impact of environmental concentrations in the OSPAR Maritime Area. The work of OSPAR complements that by other international organisations, such as the European Commission (EU) and the International Atomic Energy Agency (IAEA).
OSPAR, through the Radioactive Substances Committee (RSC), undertakes periodic evaluations to analyse the progress that Contracting Parties to the OSPAR Convention have made against the objectives of the OSPAR Radioactive Substances Strategy (RSS). The Fifth Periodic Evaluation (5PE) published in 2022, is a comprehensive evaluation that assesses authorised discharges from the nuclear and non-nuclear sectors, environmental concentrations of radionuclides in the OSPAR Maritime Area and the radiological consequences of those concentrations. The 5PE assesses data available up to 2018 and builds upon the data and conclusions of the previous four periodic evaluations to provide the scientific underpinning for the Radioactive Substances Thematic Assessment for the QSR 2023.
Q3. Did it work?
Discharges of radioactive substances from the nuclear sector have shown progressive and substantial reductions
OSPAR has carried out assessments of indicators for each nuclear sub-sector (for individual Contracting Parties where discharges from these sub-sectors occur to the OSPAR Maritime Area and for the sum of all such discharges) as well as for the nuclear sector as a whole (the sum of all such discharges from all sub-sectors). These assessments have determined whether there were progressive reductions over the period 1995 to 2018 and substantial reductions in discharges in the assessment period of 2012 to 2018 compared to the baseline period (1995 to 2001). The combination of these outcomes has been used to determine whether the discharge element of the first objective of the OSPAR RSS under the North-East Atlantic Environment Strategy (NEAES) 2010-2020 has been fulfilled. From the assessments carried out there is clear evidence that the discharge element of the first objective of the OSPAR RSS under the NEAES 2010-2020 has been fulfilled in the majority of cases, that is, in these situations there have been progressive and substantial reductions in discharges. Further, it should be noted that no assessments revealed any actual increase in discharges.
For the nuclear sector as a whole, there was evidence that the discharge element of the first objective of the OSPAR RSS under the NEAES 2010-2020 had been fulfilled for total alpha, total beta (excluding tritium), Tc-99 and Cs-137. Compared to the baseline period, there had been overall reductions in total alpha discharges by a factor of around 2 and by a factor of 13 for total beta (excluding tritium). Figure 2 shows the reductions in total alpha and total beta (excluding tritium) for the four nuclear sub-sectors. Overall discharges of Tc-99 and Cs-137 showed reductions by a factor of 66 and around 3, respectively. In the case of Pu-239,240, although the statistical assessment showed no evidence that the discharge element of the first objective of the OSPAR RSS under the NEAES 2010-2020 had been fulfilled, discharges of Pu-239,240 from the nuclear sector as a whole showed a reduction by a factor of 1,2. It is anticipated that discharges of Pu-239,240 will continue to decrease following the cessation of nuclear fuel reprocessing operations at Sellafield which is expected during 2022.
Figure 2: Comparison of mean total beta (excluding tritium) discharges for the baseline period 1995-2001 (black columns) and assessment period 2012-2018 (grey columns) for the different nuclear sub-sectors
Figure 3: Comparison of mean total beta (excluding tritium) discharges for the baseline period 1995-2001 (black columns) and assessment period 2012-2018 (grey columns) for the different nuclear sub-sectors
Best Available Techniques have been implemented in the nuclear sector
Contracting Parties have now completed seven rounds of reporting under PARCOM Recommendation 1991/4 on the implementation of BAT in the nuclear sector and have begun a further round of reporting under the new OSPAR Recommendation 2018/1 (as amended). Reporting rounds 5, 6 and 7 were completed during the period 2010 to 2020. Implementation reports for individual Contracting Parties and overviews of all national statements after the completion of each round of reporting under PARCOM Recommendation 1991/4 have been published by OSPAR. All Contracting Parties have been found to be applying BAT in the nuclear sector under PARCOM Recommendation 1991/4, which has in turn contributed to meeting the objectives of the OSPAR RSS under the NEAES 2010-2020.
Discharges of radioactive substances from the oil and gas sub-sector have mostly remained unchanged
For the oil and gas sub-sector, assessments have been carried out to determine whether there were progressive reductions over the period 2005 to 2018 and substantial reductions in discharges in the assessment period of 2012 to 2018 compared to the baseline period (2005 to 2011). The assessments carried out for the oil and gas sub-sector indicate that, in most cases, discharges of radioactive substances from the oil and gas sub-sector have remained unchanged. However, there is evidence that the discharge element of the first objective of the OSPAR RSS under the NEAES 2010-2020 has been fulfilled in some cases. Further, it should be noted that none of the assessments carried out for individual Contracting Parties revealed any actual increase in discharges.
Discharges from the other non-nuclear sub-sectors are not assessed, as either they are not significant contributors to discharged activities or there are uncertainties associated with the reported data and the amount entering the marine environment.
Best Available Techniques not available specifically for radioactive substances from the oil and gas sub-sector
For the oil and gas sub-sector, OSPAR Recommendation 2001/1 (as amended) requires the application of BAT to prevent pollution from oil and ‘other substances’ caused by discharges of produced water. While this Recommendation is not specific to radioactive substances, its implementation can result in reduced discharges of produced water and hence reduced discharges of naturally occurring radionuclides. In some circumstances, discharges of produced water from oil and gas installations can be reduced by re-injection. Re-injection as an option depends on a number of variables and not all production fields have sub-surface geology that would allow or accommodate the re-injection of produced water. Where produced water is routinely re-injected, the availability of the injection system can also result in periodic discharges of produced water.
Q4. How does this field affect the overall quality status?
Environmental concentrations are close to or lower than historic levels
From the assessments that OSPAR has carried out on environmental concentrations of indicator radionuclides for the nuclear sector there is clear evidence that the second objective of the OSPAR RSS under the NEAES 2010-2020 has been fulfilled or more than fulfilled in all of the cases except one. In these situations, therefore, it is clear that environmental concentrations in the assessment period are close to or lower than historic levels. Examples of environmental concentrations for the period 1995 to 2018 are given in Figure 4. In OSPAR RSC sub-region 32, the statistical assessment showed evidence of an increase in environmental concentrations of H-3 in seawater between the assessment and baseline periods, which probably reflects the influence of the tritium discharges from the French nuclear fuel reprocessing facility at la Hague in OSPAR RSC sub-region 2. OSPAR has recognised in previous periodic evaluations that the industrial scale abatement of tritium in the liquid effluent of nuclear power stations and nuclear reprocessing facilities is currently not technically feasible.
Figure 4: Examples of environmental concentrations for the period 1995 to 2018, showing Cs-137 in seawater in OSPAR RSC sub-region 10, Pu-239,240 in molluscs for OSPAR RSC sub-region 6, Cs-137 in fish for OSPAR RSC sub-region 12 and Tc-99 in seaweed for OSPAR RSC sub-region 6 (evidence of a reduction in all cases). Time periods indicated are baseline period 1995-2001 (black columns), assessment period 2012-2018 (grey columns) and intervening years (white columns). Note, different scales are used for the vertical axes in the examples above.
No significant radiological impact from environmental concentrations
OSPAR has carried out assessments to determine the radiological impact of mean values of environmental concentrations of indicator radionuclides for the nuclear sector (H-3, Tc-99, Cs-137 and Pu-239,240) in seawater in the assessment period. In all cases except one the annual doses from the indicator radionuclides would be a fraction of those corresponding to the relevant environmental reference levels. This would not result in a significant radiological impact on humans or the marine environment. This includes the situation in OSPAR RSC sub-region 3, where there was evidence of an increase in environmental concentrations of H-3 in seawater between the assessment and baseline periods. The impact of the environmental concentration of H-3 in the OSPAR Maritime Area is far lower than the trivial dose. The one case where the OSPAR methodology did not conclude that the impact was trivial, was for Pu 239,240 in seawater in OSPAR RSC sub-region 6. However, more focused assessments carried out by the United Kingdom have concluded that the radiological impacts resulting from Pu-239,240 in seawater in OSPAR RSC sub-region 6 are very low.
OSPAR has also carried out assessments to determine the radiological impact of modelled additional concentrations of indicator radionuclides for produced water from the non-nuclear oil and gas sub-sector over the wider OSPAR Maritime Area. In all cases the annual doses from the additional concentrations of these indicator radionuclides in seawater would be a fraction of those corresponding to relevant environmental reference levels. Again, this would not result in a significant radiological impact on humans or the marine environment.
Q5. What do we do next?
Preventing pollution of the OSPAR Maritime Area is an ongoing task
Contracting Parties have successfully fulfilled the objectives of the OSPAR RSS for 2020 under the NEAES 2010-2020 and have made significant progress towards fulfilling the ultimate aim of concentrations in the environment near background values for naturally occurring radioactive substances and close to zero for artificial radioactive substances. In doing so, Contracting Parties have prevented pollution of the OSPAR Maritime Area by ionising radiation. However, delivering the aims of the OSPAR Convention is an ongoing task. Therefore, new strategic and operational objectives for radioactive substances were agreed by the Ministerial Meeting of the OSPAR Commission 2021 in Cascais, Portugal, under the North-East Atlantic Environment Strategy 2030. Under the theme of Clean seas, the new strategic objective for radioactive substances states that:
OSPAR will prevent pollution by radioactive substances in order to safeguard human health and to protect the marine environment with the ultimate aim of achieving and maintaining concentrations in the marine environment at near background values for naturally occurring radioactive substances and close to zero for human made radioactive substances.
This work will be carried forward through the delivery of the following operational objectives:
S3.O1: On an ongoing basis OSPAR will further prevent, progressively reduce or, where that is not practicable, minimise discharges of radioactive substances through the application of Best Available Techniques (BAT), taking into account technical feasibility, radiological impact and legitimate uses of the sea.
S3.O2: By 2025 OSPAR will identify and consider any obstacles in achieving further reductions in environmental concentrations of radioactive substances in the marine environment and examine possible solutions where appropriate.
S3.O3: By 2025 OSPAR will identify the different types of loss of radioactive substances that may contribute to pollution of the marine environment. By 2027 OSPAR will determine if any additional measures are required to prevent such pollution, to the extent that such pollution is not already the subject of effective measures agreed by other international organisations or prescribed by other international conventions.
S3.O4: By 2028 OSPAR will, following the outcome of the Quality Status Report 2023, address, where appropriate, any uncertainties by reviewing and updating methodologies to better determine the possible impact of releases, emissions and losses of radioactive substances on marine ecosystems.
As an addition operational objective (S10.O3), OSPAR has agreed to assess the current and projected impacts of climate change and ocean acidification on the OSPAR Maritime Area and its uses, to inform the development of national and international actions. For radioactive substances this work will influence the review of the currently agreed assessment methodologies and the data and parameters upon which these methodologies rely.
Table 1: Summary table for radioactive substances
| Region | Overall change in discharges | Overall change in environmental activity concentration of assessed radionuclides | Key factors and pressures (now and for the future) | Outlook for pressures | Action needed |
| Arctic Waters (Region I) | Nuclear industry: not applicable Offshore oil/gas industry: ↔ | ↓ | Dispersion of discharges from the nuclear industry from Regions II and III | Further reduction of discharges from the nuclear sector | Continued monitoring and assessment by OSPAR |
| Greater North Sea (Region II) | Nuclear industry: ↓ Offshore oil/gas industry: ↔ | ↓ | Discharges from the nuclear industry in Region II | Further reduction of discharges from the nuclear sector | Continued monitoring and assessment by OSPAR |
| Celtic Seas) Region III | Nuclear industry: ↓ Offshore oil/gas industry: ↔ | ↓ | Discharges from the nuclear industry in Region III | Further reduction of discharges from the nuclear sector | Continued monitoring and assessment by OSPAR |
| Bay of Biscay and Iberian Coast (Region IV) | Nuclear industry: ↓ Offshore oil/gas industry: not applicable | ↓ | Discharges from the nuclear industry in Region IV | Further reduction of discharges from the nuclear sector | Continued monitoring and assessment by OSPAR |
| Wider Atlantic (Region V) | Not applicable | No data | Dispersion of discharges from the nuclear industry in Regions II and III | Increasing climate change impacts | Research into climate change impacts |
Footnotes
1The time taken for the radioactivity of a specified isotope to fall to half its original value
2OSPAR RSC agreed to split the OSPAR Maritime Area into 15 sub-regions, taking into account specific sources, prevailing currents and the areas used in the MARINA II study. These 15 OSPAR RSC sub-regions generally represent subdivisions of the five main regions of the OSPAR Maritime Area, although some of the boundaries do not coincide exactly. See Figure S.1.
Contributors
Lead author: Justin Gwynn
Supporting authors: Adam Stackhouse and Carol Robinson
Supported by: Intersessional Correspondence Group for the Fifth Periodic Evaluation, Radioactive Substances Committee, Intersessional Correspondence Group for the Quality Status Report, Intersessional Correspondence Group on Ecosystem Assessment Outlook – Cumulative Effects Assessment, Intersessional Correspondence Group on Economic and Social analyses, Climate Change Expert Group and the OSPAR Secretariat
Citation
OSPAR, 2023. Radioactive Substances Committee Thematic Assessment. In: OSPAR, 2023: Quality Status Report 2023. OSPAR Commission, London. Available at: https://oap.ospar.org/en/ospar-assessments/quality-status-reports/qsr-2023/thematic-assessments/rsc