Editing Group 7 element (section)

== Toxicity and precautions ==

Manganese compounds are less toxic than those of other widespread metals, such as [[nickel]] and [[copper]].<ref>{{cite book|pages=31 |title=Manganese|first=Heather|last=Hasan|publisher=The Rosen Publishing Group|date=2008|isbn=978-1-4042-1408-8 |url=https://books.google.com/books?id=nRmpEaudmTYC&pg=PA31}}</ref> However, exposure to manganese dusts and fumes should not exceed the ceiling value of 5&nbsp;mg/m<sup>3</sup> even for short periods because of its toxicity level.<ref>{{cite web|url=http://www.environmentwriter.org/resources/backissues/chemicals/manganese.htm |archive-url=https://web.archive.org/web/20060828211701/http://www.environmentwriter.org/resources/backissues/chemicals/manganese.htm |url-status=dead |archive-date=28 August 2006 |title=Manganese Chemical Background |access-date=30 April 2008 |publisher=Metcalf Institute for Marine and Environmental Reporting University of Rhode Island |date=April 2006 }}</ref> Manganese poisoning has been linked to impaired motor skills and cognitive disorders.<ref>{{cite web|url=http://rais.ornl.gov/tox/profiles/mn.html|publisher=Oak Ridge National Laboratory|title=Risk Assessment Information System Toxicity Summary for Manganese|access-date=23 April 2008}}</ref>

Technetium has low chemical toxicity. For example, no significant change in blood formula, body and organ weights, and food consumption could be detected for rats which ingested up to 15&nbsp;μg of technetium-99 per gram of food for several weeks.<ref>{{cite book|url=https://books.google.com/books?id=QLHr-UYWoo8C&pg=PA392|pages=392–395|title=Technetium in the environment|author=Desmet, G.|author2=Myttenaere, C.|publisher=Springer|isbn=978-0-85334-421-6|date=1986}}</ref> In the body, technetium quickly gets converted to the stable {{chem|TcO|4|-}} ion, which is highly water-soluble and quickly excreted. The radiological toxicity of technetium (per unit of mass) is a function of compound, type of radiation for the isotope in question, and the isotope's half-life.{{sfn|Schwochau|2000|pp=371–381}} However, it is radioactive, so all isotopes must be handled carefully. The primary hazard when working with technetium is inhalation of dust; such [[radioactive contamination]] in the lungs can pose a significant cancer risk. For most work, careful handling in a [[fume hood]] is sufficient, and a [[glove box]] is not needed.{{sfn|Schwochau|2000|p=40}}

Very little is known about the toxicity of rhenium and its compounds because they are used in very small amounts. Soluble salts, such as the rhenium halides or perrhenates, could be hazardous due to elements other than rhenium or due to rhenium itself.{{sfn|Emsley|2001|p=358-361}} Only a few compounds of rhenium have been tested for their acute toxicity; two examples are potassium perrhenate and rhenium trichloride, which were injected as a solution into rats. The perrhenate had an [[Median lethal dose|LD<sub>50</sub>]] value of 2800&nbsp;mg/kg after seven days (this is very low toxicity, similar to that of table salt) and the rhenium trichloride showed LD<sub>50</sub> of 280&nbsp;mg/kg.<ref>{{cite journal|title=Pharmacology and toxicology of potassium perrhenate and rhenium trichloride|pages=321–323|first =Thomas J.|last=Haley|author2=Cartwright, Frank D. |doi=10.1002/jps.2600570218|journal=Journal of Pharmaceutical Sciences|volume=57|issue=2|date=1968|pmid=5641681}}</ref>