Evaluation of radioactivity concentrations from the Fukushima nuclear accident in fish products and associated risk to fish consumers

Radioactive contamination of the Pacific Ocean following the Fukushima nuclear accident has raised public concerns about seafood safety(1, 2). Many people are wondering whether fish products from the Pacific Ocean and Japan are safe to eat 2 y after the accident. There is also some concern about seafood caught locally, outside of Japan. Based on monitoring data reported in July 2013, radioactive caesium concentrations in fish products from Fukushima and adjacent prefectures are evaluated. Resulting radiation doses from annual consumption at average contamination levels and occasional fish meals at much higher levels of caesium are calculated. To put radiation doses from caesium intake in perspective, comparisons are made to doses from naturally occurring radioactive polonium commonly found in fish. Discussion and conclusions are given subsequently. The Tokyo Electric Power Company has conducted routine radioactivity measurements (134Cs and 137Cs) of various marine fish and shellfish in the ocean area within a 20-km radius of the Fukushima Daiichi Nuclear Power Station (FDNPS). Based on their posted summary on 16 August 2013(3), a total of 100 fish samples were collected from 7 to 23 July, offshore of the FDNPS and outside of its port area. The nuclide analysis report showed that 134Cs was detected in 64 samples with concentrations varying from 3.5 to 130 Bq kg-1. 137Cs was detected in 79 samples and the concentration varied from 3.6 to 260 Bq kg-1. On average, fish and shellfish caught within 20-km offshore of the FDNPS contain 12 Bq kg-1 of 134Cs and 26 Bq kg-1 of 137Cs. The Japanese Fisheries Agency (JFA), in cooperation with the relevant prefectural governments and organisations, has conducted sampling and inspections of fishery products at the major fishing ports in Fukushima and adjacent prefectures on a weekly basis to examine the possible contamination of fishery products by radioactive materials released from the FDNPS. (authors)