Editing Thorium (section)

===Biological===
Thorium is odourless and tasteless.<ref>{{cite web|url=https://www.atsdr.cdc.gov/toxprofiles/tp147.pdf|title=Toxicological Profile for Thorium|publisher=Agency for Toxic Substances and Disease Registry U.S. Public Health Service|date=1990|page=4|access-date=5 September 2016|archive-date=21 October 2004|archive-url=https://web.archive.org/web/20041021114032/https://www.atsdr.cdc.gov/toxprofiles/tp147.pdf|url-status=live}}</ref> The chemical toxicity of thorium is low because thorium and its most common compounds (mostly the dioxide) are poorly soluble in water,<ref name="Schneckenstein">{{cite report|last1=Merkel |first1=B. |last2=Dudel |first2=G. |display-authors=etal |year=1988 |archive-url=https://web.archive.org/web/20130108094057/http://www.geo.tu-freiberg.de/~merkel/schneckenstein.PDF |archive-date=8 January 2013 |url=http://www.geo.tu-freiberg.de/~merkel/schneckenstein.PDF |title=Untersuchungen zur radiologischen Emission des Uran-Tailings Schneckenstein |publisher=Sächsisches Staatsministerium für Umwelt und Landesentwicklung |language=de}}</ref> precipitating out before entering the body as the hydroxide.{{sfn|Stoll|2005|p=34}} Some thorium compounds are chemically moderately [[toxic]], especially in the presence of strong complex-forming ions such as citrate that carry the thorium into the body in soluble form.{{sfn|Stoll|2005|p=35}} If a thorium-containing object has been chewed or sucked, it loses 0.4% of thorium and 90% of its dangerous daughters to the body.<ref name="Poljanc" /> Three-quarters of the thorium that has penetrated the body accumulates in the [[skeleton]]. Absorption through the skin is possible, but is not a likely means of exposure.<ref name="epa" /> Thorium's low solubility in water also means that excretion of thorium by the kidneys and faeces is rather slow.{{sfn|Stoll|2005|p=35}}

Tests on the thorium uptake of workers involved in monazite processing showed thorium levels above recommended limits in their bodies, but no adverse effects on health were found at those moderately low concentrations. No chemical toxicity has yet been observed in the [[tracheobronchial tract]] and the lungs from exposure to thorium.{{sfn|Stoll|2005|p=34}} People who work with thorium compounds are at a risk of [[dermatitis]]. It can take as much as thirty years after the ingestion of thorium for symptoms to manifest themselves.<ref name="Emsley2011" /> Thorium has no known biological role.<ref name="Emsley2011" />