Editing Slag (section)

==Health and environmental effect==
{{See also|Particulates#Controlling technologies and measures}}
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[[File:Indiana-Harbor-scrap.jpg|left|thumb|227x227px|Pile of steelmaking slag at the [[Cleveland-Cliffs]] Indiana Harbor steelmaking facility.]]
Slags are transported along with slag tailings to "slag dumps", where they are exposed to weathering, with the possibility of [[Leaching (chemistry)|leaching]] of toxic elements and hyperalkaline runoffs into the soil and water, endangering the local ecological communities. Leaching concerns are typically around non-ferrous or base metal slags, which tend to have higher concentrations of toxic elements. However, ferrous and ferroalloy slags may also have them, which raises concerns about highly weathered slag dumps and upcycled materials.<ref name=":2" /><ref name=":3" />

Dissolution of slags can produce highly [[alkaline]] [[groundwater]] with [[pH]] values above 12.<ref name=":1">{{Cite journal|last1=Roadcap|first1=George S.|last2=Kelly|first2=Walton R.|last3=Bethke|first3=Craig M.|date=2005|title=Geochemistry of Extremely Alkaline (pH > 12) Ground Water in Slag-Fill Aquifers|url=http://dx.doi.org/10.1111/j.1745-6584.2005.00060.x|journal=[[Ground Water]]|volume=43|issue=6|pages=806–816|doi=10.1111/j.1745-6584.2005.00060.x|pmid=16324002|bibcode=2005GrWat..43..806R |s2cid=12325820 |issn=0017-467X}}</ref> The [[calcium silicate]]s (CaSiO<sub>4</sub>) in slags react with water to produce [[calcium hydroxide]] ions that leads to a higher concentration of [[hydroxide]] (OH-) in [[ground water]]. This [[alkalinity]] promotes the mineralization of dissolved {{CO2}} (from the atmosphere) to produce [[calcite]] (CaCO<sub>3</sub>), which can accumulate to as thick as 20&nbsp;cm. This can also lead to the dissolution of other metals in slag, such as iron (Fe), [[manganese]] (Mn), [[nickel]] (Ni), and [[molybdenum]] (Mo), which become insoluble in water and mobile as [[Particulates|particulate matter]]. The most effective method to [[Detoxification|detoxify]] alkaline ground water discharge is [[air sparging]].<ref name=":1" />

Fine slags and slag dusts generated from [[Milling (machining)|milling]] slags to be recycled into the smelting process or [[upcycling|upcycled]] in a different industry (e.g. construction) can be carried by the wind, affecting a larger ecosystem. It can be ingested and inhaled, posing a direct [[health risk]] to the communities near the [[Chemical plant|plants]], mines, disposal sites, etc.<ref name=":2">{{Citation|last1=Ettler|first1=Vojtěch|title=Chapter 6: Environmental Impact of Slag Particulates|date=2021-08-04|url=https://pubs.rsc.org/en/content/chapter/bk9781788018876-00174/978-1-78801-887-6|work=Metallurgical Slags|pages=174–193|language=en|access-date=2021-11-27|last2=Kierczak|first2=Jakub|series=Chemistry in the Environment|doi=10.1039/9781839164576-00174|isbn=978-1-78801-887-6|s2cid=238952198}}</ref><ref name=":3">{{Citation|last1=Ettler|first1=Vojtěch|title=Chapter 5: Slag Leaching Properties and Release of Contaminants|date=2021-08-04|url=https://pubs.rsc.org/en/content/chapter/bk9781788018876-00151/978-1-78801-887-6|work=Metallurgical Slags|pages=151–173|language=en|access-date=2021-11-27|last2=Vítková|first2=Martina|series=Chemistry in the Environment|doi=10.1039/9781839164576-00151|isbn=978-1-78801-887-6|s2cid=238945892}}</ref>