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
Caesium Known year-to-year variation within that period allows correlation with soil and sediment layers. Caesium-134, and to a lesser extent caesium-135, have also been used in hydrology to measure the caesium output by the nuclear power industry. While they are less prevalent than either caesium-133 or caesium-137, these bellwether isotopes are produced solely from anthropogenic sources. Caesium and mercury were used as a propellant in early ion engines designed for spacecraft propulsion on very long interplanetary or extraplanetary missions. The fuel was ionized by contact with a charged tungsten electrode. But corrosion by caesium on spacecraft components has pushed development in