2020-02-27
The draft Cancer Risk from Exposure to Plutonium and Uranium is now available for public consultation. We welcome comments from individuals and organisations. The draft document can be downloaded from the ICRP website. Comments must be submitted through the ICRP website no later than June 5, 2020.
The objective of this publication is to provide a detailed review of results from recent epidemiological studies of cancer risk from exposure to plutonium and uranium, and how these results relate to the assumptions currently used for protection against alpha radiation. For plutonium, the two main studies are of the cohorts of workers employed at the nuclear installations at Mayak in the Russian Federation and at Sellafield in the United Kingdom. The analysis of the Mayak cohort provides an estimate of the slope of the dose-response for lung cancer risk, while at lower levels of plutonium exposure, the Sellafield cohort provides results that, within relatively large confidence intervals, are consistent with those for the Mayak cohort. Results from the Mayak cohort also show an association between plutonium exposure and risks of liver and bone cancers, but not of leukaemia. Lifetime excess risk of lung cancer mortality has been calculated for scenarios of acute and chronic inhalation of plutonium nitrate and plutonium oxide, similarly to that done previously for radon and its decay products in Publication 115. Estimated lifetime excess risks of lung cancer mortality per unit absorbed dose are close to those derived from miner studies for exposure to radon and its progeny, and are compatible with the assumption of a radiation weighting factor of 20 for alpha particles. Epidemiological studies of cancer risk associated with uranium exposure have been conducted among cohorts of European and North American workers involved in the nuclear fuel cycle. Current results do not allow the reliable derivation of dose-risk models for uranium for any cancer type. Continuation of efforts to improve dose assessment associated with uranium and plutonium exposure is recommended for future research.