Research and analysis

Radionuclide transfer parameter review: summary

Published 31 July 2026

Applies to England

1. Chief Scientist’s Group report summary

This project examined the environmental behaviour of ten radionuclides whose importance in environmental dose assessments is novel or increasing. The project reviewed the published scientific literature to identify the state-of-the-art knowledge of environmental transfer parameters for the ten radionuclides of interest.

The findings will help the Environment Agency assess the impacts of radioactive waste disposal and discharge operations on the public and the environment and to better regulate the nuclear and non-nuclear industry.

1.1 Background

The nuclear and non-nuclear industry routinely discharge low levels of radioactive waste to the environment via gaseous waste and/or wastewater treatment systems. The Environment Agency assesses the potential impacts of these waste discharges on humans and wildlife as part of its regulation of radioactive substances. These assessments require knowledge of transfer parameters to predict the fate and transport of radionuclides in the environment. However, existing parameter data may be outdated or sparse. Examination of the scientific literature to identify new or updated transfer parameter values would help address these uncertainties and strengthen the Environment Agency’s radiological assessments.

1.2 Approach

A review of the published scientific literature for environmental transfer parameter data was performed. The project evaluated the suitability of new or updated information for five different transfer parameters:

• Concentration factor: transfer of radionuclides from soil to plants, and from plants to animal foodstuffs.
• Concentration ratio: transfer of radionuclides to animal tissue from the surrounding environment.
• Distribution coefficient: transfer of radionuclides between soil/sediment and water bodies
• Gaseous uptake factor: transfer of airborne radionuclides (gases) to plants.
• Gastrointestinal factor: transfer of ingested radionuclides to an animal’s gut and then excretion.

The project examined transfer parameter data for ten radionuclides that are relevant to environmental dose assessments: tritium (3H), carbon-14 (14C), phosphorus-32 (32P), yttrium-86 (86Y), iodine-129 (129I), lutetium-177 (177Lu), rhenium-186 (186Re), rhenium-188 (188Re), radium-223 (223Ra), and actinium-225 (225Ac).

1.3 Results

The literature review found several examples of new or updated transfer parameter data for many of the ten radionuclides. For example, version 2.0 of the Environmental Risk from Ionising Contaminants: Assessment and management (ERICA) Tool provides scientifically robust and modern information that may aid wildlife dose assessments. However, transfer parameter data remains limited or completely absent for some radionuclides used in nuclear medicine (e.g., 177Lu, 186/188Re, and 225Ac). These gaps mean that improvements to current assessment approaches may not be possible for certain novel or rarely used radionuclides.

2. Conclusions

The project reviewed the published scientific literature for the latest information on radionuclide environmental transfer parameters. Recent studies contain new parameter datasets that may strengthen environmental assessments and help reduce uncertainties for some radionuclides. On the other hand, information on new medical radionuclides in the published literature was sparse and offers limited benefits for these assessments. The knowledge and evidence gaps identified in this project may need to be addressed through further research to help ensure that environmental radiological assessment approaches remain up to date.

This is important for both the Environment Agency and those we regulate (such as the nuclear and non-nuclear industry) who regularly assess the impacts of releasing man-made radioactivity into the environment.

2.1 Publication details

This summary relates to information from project SC250035, reported in detail in the following output:

• Report: SC250035
• Title: Radionuclide transfer parameter review
• Science manager: Adam Lang, Environment and Human Health Research, Chief Scientist’s Group
• Research contractor: Eden Nuclear and Environment Ltd

This project was commissioned by the Environment Agency’s Chief Scientist’s Group, which provides scientific knowledge, tools and techniques to enable us to protect and manage the environment as effectively as possible.

Enquiries: research@environment-agency.gov.uk.

© Environment Agency