Editing Group 3 element (section)

==Biological chemistry==
Group 3 metals have low availability to the biosphere. Scandium, yttrium, and lutetium have no documented biological role in living organisms. The high radioactivity of lawrencium would make it highly toxic to living cells, causing radiation poisoning.

Scandium concentrates in the liver and is a threat to it; some of its compounds are possibly [[carcinogen]]ic, even though in general scandium is not toxic.<ref name="sc">{{cite web|year=1998|publisher=Lenntech|title=Scandium (Sc) — chemical properties of scandium, health effects of scandium, environmental effects of scandium|author=Lenntech|access-date=2011-05-21|url=http://www.lenntech.com/periodic/elements/sc.htm}}</ref> Scandium is known to have reached the food chain, but in trace amounts only; a typical human takes in less than 0.1&nbsp;micrograms per day.<ref name="sc"/> Once released into the environment, scandium gradually accumulates in soils, which leads to increased concentrations in soil particles, animals and humans. Scandium is mostly dangerous in the working environment, due to the fact that damps and gases can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. The element is known to damage cell membranes of water animals, causing several negative influences on reproduction and on the functions of the nervous system.<ref name="sc"/>

Yttrium tends to concentrate in the liver, kidney, spleen, lungs, and bones of humans.<ref>{{cite journal|journal = Journal of Biological Chemistry|year = 1952|volume = 195|pages = 837–841|title = The Skeletal Deposition of Yttrium|first1 = N. S.|last1 = MacDonald|last2 = Nusbaum|first2 = R. E.|last3 = Alexander|first3 = G. V.|pmid = 14946195|issue = 2|doi = 10.1016/S0021-9258(18)55794-X|doi-access = free}}</ref> There is normally as little as 0.5&nbsp;milligrams found within the entire human body; human [[breast milk]] contains 4&nbsp;ppm.<ref name="Emsley495" /> Yttrium can be found in edible plants in concentrations between 20&nbsp;ppm and 100&nbsp;ppm (fresh weight), with [[cabbage]] having the largest amount.<ref name="Emsley495">[[#Emsley2001|Emsley 2001]], pp. 495–498</ref> With up to 700&nbsp;ppm, the seeds of woody plants have the highest known concentrations.<ref name="Emsley495"/>

Lutetium concentrates in bones, and to a lesser extent in the liver and kidneys.<ref name="Emsley240"/> Lutetium salts are known to cause metabolism and they occur together with other lanthanide salts in nature; the element is the least abundant in the human body of all lanthanides.<ref name="Emsley240"/> Human diets have not been monitored for lutetium content, so it is not known how much the average human takes in, but estimations show the amount is only about several micrograms per year, all coming from tiny amounts taken by plants. Soluble lutetium salts are mildly toxic, but insoluble ones are not.<ref name="Emsley240">[[#Emsley2001|Emsley 2001]], p. 240</ref>