Are some radionuclides more dangerous than others?
Yes. As a rule, alpha emitting radionuclides are more dangerous than beta and gamma emitting radionuclides, especially if they are taken internally into the body (e.g. through eating contaminated food or inhaling contaminated air). External irradiation by beta particles and gamma rays can also be a serious problem for some radionuclides, for example through standing on contaminated ground or holding a powerful radiation source. Dangerous alpha emitters include plutonium-239, and cobalt-60 is a strong gamma emitter for which external irradiation can be a problem.
