R02015: The radiological significance of farmed fish

Study Duration: April 2001 to October 2002

Contractor: The Centre for Environment, Fisheries and Aquaculture Science (CEFAS)

A previous study undertaken by CEFAS suggested that naturally-occurring polonium-210 levels might be high in fish-meal. Therefore farmed fish that were fed fish-meal might have higher levels of polonium-210 than wild fish. If true this would imply that the radiation exposure of consumers eating farmed fish would be greater than those consumers eating wild fish. The project sought to determine the concentrations of selected radionuclides in UK farmed fish and their feedstuffs; evaluate transfer factors from feed to fish for these nuclides and to assess the consequent radiation exposure to consumers.

The project examined a representative cross-section of UK salmon and trout farms and samples of both fish and feed were collected and analysed. The sample preparation and analytical techniques were the same as those used in the Agency’s routine radioactivity monitoring programmes, the results of which are published in the annual RIFE report. The results obtained were compared with other farmed fish data and the radiation exposure of consumers was assessed.

The Radioactivity in Food and the Environment (RIFE) report is published annually by the Agency in conjunction with the Scottish Environment Protection Agency (SEPA), the Environment Agency (EA) and the Environment and Heritage Service of Northern Ireland (EHSNI).

For carbon-14, technetium-99, polonium-210 and gamma emitting radionuclides, concentrations in farmed fish were similar to those found in wild fish. However, a difference was observed for lead-210 where values in farmed fish were an order of magnitude lower than those in wild fish. Transfer factors for radionuclides in fish feed to farmed fish were calculated. Much of the assessed radiation exposure was due to naturally-occurring lead-210 and polonium-210, and as these were present in concentrations which were within the expected range of natural levels in fish, the radiation exposure from man-made sources of radioactivity may be regarded as trivial.

The report recommended that:

• The Agency's radioactivity monitoring programme be reviewed to include more representative sampling of farmed fish;
• the calculated transfer factors be used in the Agency's prospective assessments of consumer radiation exposure.

These results give confidence that the radiation exposure of fish consumers is similar for both farmed and wild fish and such exposures are principally due to the naturally-occurring radioactivity. The report's recommendations will be acted upon by the Agency and the monitoring programme will be revised.

Final report is available from the FSA Library and Information Centre. To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency (Tel: 020 7276 8181/8182 or by email to: library&info@foodstandards.gsi.gov.uk).

Contact: Darren Cutts
Tel: 020 7276 8728 ( Intl +44 (0) 7276 8728 )
Email: darren.cutts@foodstandards.gsi.gov.uk