Facts
Dysprosium has no biological role. Soluble dysprosium salts are mildly toxic by ingestion; insoluble salts are non toxic.
Applications
Dysprosium is used in nuclear reactors, to make laser materials, nuclear reactor control rods, as sources of infrared radiation for studying chemical reactions. Another use in the field of radioactivity is in dosimeters for monitoring exposure to ionizing radiation.
Dysprosium in the environment
Dysprosium is one of the more abundant lanthanide elements and is more than twice as abundant as tin. Dysprosium is never encountered as the free element, but is found in many minerals. The most important ores are monazite and bastnasite. World production in around 100 tonnes per year. Dysprosium poses no environmental threat to plants and animals.
Source: Dysprosium (Dy) - Chemical properties, Health and Environmental effects