Research and analysis

Behaviour of lutetium-177 discharged into UK wastewater systems: summary

Published 31 July 2026

Applies to England

1. Chief Scientist’s Group report summary

This project investigated the behaviour of the novel medical radionuclide lutetitum-177 (177Lu) in wastewater environments through a field monitoring investigation. The project measured 177Lu levels in a wastewater treatment works and river after a hospital administration of a 177Lu cancer treatment. Its findings will help the Environment Agency better understand the environmental impacts of 177Lu waste discharges from hospitals.

1.1 Background

Hospitals are increasingly using 177Lu in cancer treatments which will increase the amount of 177Lu discharged in hospital wastewaters. The Environment Agency assesses the potential impacts of these waste discharges on people and wildlife as part of its radioactive substances regulation. Such assessments require a detailed understanding of the radionuclide’s environmental behaviour. However, 177Lu is a relatively new radionuclide in cancer treatments and there is limited information on its fate and transport in wastewater systems. Generating monitoring data for 177Lu in wastewater environments would help address this knowledge gap and could strengthen the Environment Agency’s radiological assessments.

1.2 Approach

Targeted environmental sampling and analysis was performed over the course of one week, timed to coincide with the administration of a 177Lu cancer treatment at a nearby hospital. Supplementary sampling and analysis was also undertaken the day proceeding the targeted treatment date to establish baseline levels of 177Lu in the environment. The project measured 177Lu concentrations in three types of environmental samples:

• sewage sludge in a wastewater treatment works that received 177Lu bearing waste from the hospital.
• river water that received treated effluent from the wastewater treatment works.
• sediment in the river that received treated effluent from the wastewater treatment works.

The monitoring data were used to calculate parameters that describe 177Lu behaviour in wastewater environments. The project compared the calculated parameter values with the Environment Agency’s current parameter data to identify potential differences in the predicted radiological impacts on people and the environment.

1.3 Results

The field measurements and calculations indicate that 177Lu accumulates in the wastewater and only a minor fraction transfers to sewage sludge or river water over short timescales. This is different to the Environment Agency’s current parameter values and suggests that medical and non-medical forms of a radionuclide could behave differently in a wastewater environment. However, this research focussed on one hospital and the connecting wastewater system and therefore provides limited insights into the fundamental behaviour of 177Lu in wastewater systems. The monitoring project, for example, did not consider the influence of known variations in 177Lu cancer treatments and environmental conditions on the behaviour of 177Lu.

1.4 Conclusions

The monitoring project measured 177Lu concentrations in wastewater environments. Lutetium appears to have a low affinity for solid phases in wastewater environments. Rather, 177Lu seems to largely remain in the wastewater and this result implies that the radiological impacts to people and wildlife could be dominated by exposure to the contaminated water. This is important for both the Environment Agency and the hospitals we regulate, who assess the radiological impacts of 177Lu waste discharges to wastewater systems. Nevertheless, the project was a localised study, and caution is needed if applying these conclusions to other locations.

1.5 Publication details

This summary relates to information reported in detail in the following output:

• Title: Behaviour of lutetium-177 discharged into UK wastewater systems
• Science manager: Christiana Dowds, Nuclear Regulation Group, Chief Regulators Group
• Research contractors: The University of Stirling consortia (which included Quintessa Ltd and RadEcol Consulting Ltd) and Socotec UK Ltd

This project was commissioned by the Environment Agency’s Chief Regulator’s Group.

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

© Environment Agency