Colorado State University and National Oceanic and Atmospheric Administration (US Government NOAA) publish scientific study documenting Fukushima radiation, in the form of Cesium-137 and Cesium-134, in Pacific wildlife.  Specifically, levels in Albacore Tuna of .356 Bq/Kg and .550 Bg/Kg for -134 and -137, respectively.

Source

Commentary

While these are trace-levels and meet food standards, there is still cause for concern with internal radiation of cesium, especially cesium-137. A key bit to understand is that saltwater fish, like the tuna studied in the NOAA study, do not uptake Cs-137 readily because they have high potassium levels because there is more in the saltwater. Freshwater fish uptake cesium-137 far more readily, as do livestock animals and grains.

Cs-137 bio-accumulates and is easily picked up by the body and distributed to soft tissues, especially muscle tissue.  It does affect the heart.  It is a high energy beta emitter and decays to Barium-137, which emits high energy gamma rays.  With a half-life of 30 years, it is here to stay – in our environment and our bodies.

The US limit is 1,200 Bq/Kg.  For Canada it is 1,000, and yet for Japan, it is only 100.  The issue is that eating foods with these levels of contamination will cause significant bio-accumulation in our bodies.  The book, Living with Radiation:  Protect and Heal, highlights the threat of internal emitters and why these levels should be reduced.