Evaluation of Groundhog Synergy beach monitoring system, and assessment of health risks of alpha-rich objects for beach users.
Since 2006 an intensive programme of monitoring for radioactive objects has been carried out on beaches in the vicinity of the Sellafield site in West Cumbria. Until August 2009, the Groundhog Evolution2™ beach monitoring system was used. At that time, a new beach monitoring system, Groundhog Synergy, was brought into operation. This system has a better detection capability for “alpha-rich” objects that contain alpha-emitting radionuclides such as americium-241 (241Am). The Environment Agency (EA) first sought the advice of the Health Protection Agency (HPA) on the health implications of the findings of this beach monitoring in 2007.
At the request of the Environment Agency (EA), HPA undertook an assessment of the health risks to people using the beaches, and this was published in early 2011. That assessment used only the data from the Groundhog Evolution2™ beach monitoring programme. The study presented in this report was carried out to evaluate the performance of the Synergy system, and to assess the implications of the results of the Synergy monitoring programme for the health risk assessment. Good evidence was found that the increased object find rate of Synergy can be attributed to its increased sensitivity, rather than to any real increase in the number of objects present on the beaches. New estimates were made of the health risks to beach users from the ingestion of alpha-rich objects and the changes in the estimated health risks were small and judged not to be significant. The conclusions of the original study therefore remain unchanged. That is, based on the currently available information, it may be concluded that the overall health risks to beach users are very low and significantly lower than other risks that people accept when using the beaches.