Editing Rare-earth element (section)

====On animal health====
Experiments exposing rats to various cerium compounds have found accumulation primarily in the lungs and liver. This resulted in various negative health outcomes associated with those organs.<ref name=Pagano>{{cite journal |last1=Pagano |first1=Giovanni |last2=Aliberti |first2=Francesco |last3=Guida |first3=Marco |last4=Oral |first4=Rahime |last5=Siciliano |first5=Antonietta |last6=Trifuoggi |first6=Marco |last7=Tommasi |first7=Franca |title=Rare earth elements in human and animal health: State of art and research priorities |journal=Environmental Research |volume=142 |pages=215–220 |doi=10.1016/j.envres.2015.06.039 |pmid=26164116 |bibcode=2015ER....142..215P |year=2015 |hdl=11586/148470 |hdl-access=free}}</ref> REEs have been added to feed in livestock to increase their body mass and increase milk production.<ref name=Pagano/> They are most commonly used to increase the body mass of pigs, and it was discovered that REEs increase the digestibility and nutrient use of pigs' digestive systems.<ref name=Pagano/> Studies point to a dose-response when considering toxicity versus positive effects. While small doses from the environment or with proper administration seem to have no ill effects, larger doses have been shown to have negative effects specifically in the organs where they accumulate.<ref name=Pagano/> 

The process of mining REEs in China has resulted in soil and water contamination in certain areas, which when transported into aquatic bodies could potentially bio-accumulate within aquatic biota. In some cases, animals that live in REE-contaminated areas have been diagnosed with organ or system problems.<ref name=Kyung/> REEs have been used in freshwater fish farming because it protects the fish from possible diseases.<ref name=Pagano/> One main reason why they have been avidly used in animal livestock feeding is that they have had better results than inorganic livestock feed enhancers.<ref>{{cite thesis |url=https://edoc.ub.uni-muenchen.de/5936/ |title=Rare Earth Elements in Agriculture with Emphasis on Animal Husbandry |last=Redling |first=Kerstin |date=2006 |type=Dissertation |location=LMU München |publisher=Faculty of Veterinary Medicine |access-date=2018-04-05 |archive-date=June 15, 2022 |archive-url=https://web.archive.org/web/20220615124341/https://edoc.ub.uni-muenchen.de/5936/ |url-status=live}}</ref>