Cortinarius caperatus found to be infested with maggots when picked. Mycologist David Arora recommends discarding the tough stipes. The popularity of "C. caperatus" across Europe has led to safety concerns related to its propensity to accumulate contaminants. Fungi are very efficient at absorbing radioactive isotopes of caesium from the soil and naturally have trace amounts of the element. Caesium may take the place of potassium, which exists in high concentrations in mushrooms. "C. caperatus" bioaccumulates radioactive caesium Cs—a product of nuclear testing—much more than many other mushroom species. Levels dramatically rose after the 1986 Chernobyl disaster. This is a potential health issue
Radiation effects from the Fukushima Daiichi nuclear disaster of marine life that is fished in the coastal waters off Fukushima. Despite caesium isotopic concentration in the waters off of Japan being 10 to 1000 times above concentration prior to the accident, radiation risks are below what is generally considered harmful to marine animals and human consumers. A year after the disaster, in April 2012, sea fish caught near the Fukushima power plant still contain as much radioactive Cs and Cs compared to fish caught in the days after the disaster. At the end of October 2012 TEPCO admitted that it could not exclude radioactivity releases into the ocean,