Editing Smelting (section)

==Environmental and occupational health impacts==
Smelting has serious [[human impact on the environment|effects on the environment]], producing [[wastewater]] and [[slag]] and releasing such toxic metals as [[copper]], silver, iron, [[cobalt]], and [[selenium]] into the atmosphere.<ref>{{Cite journal |last1=Hutchinson |first1=T.C. |last2=Whitby |first2=L.M. |date=1974 |title=Heavy-metal pollution in the Sudbury mining and smelting region of Canada, I. Soil and vegetation contamination by nickel, copper, and other metals |journal=Environmental Conservation |volume=1 |issue=2 |pages=123–13 2 |doi=10.1017/S0376892900004240 |bibcode=1974EnvCo...1..123H |s2cid=86686979 |issn=1469-4387}}</ref> Smelters also release gaseous [[sulfur dioxide]], contributing to [[acid rain]], which acidifies soil and water.<ref>{{Cite journal |last1=Likens |first1=Gene E. |last2=Wright |first2=Richard F. |last3=Galloway |first3=James N. |last4=Butler |first4=Thomas J. |date=1979 |title=Acid Rain |jstor=24965312 |journal=Scientific American |volume=241 |issue=4 |pages=43–51 |doi=10.1038/scientificamerican1079-43|bibcode=1979SciAm.241d..43L }}</ref>

The smelter in [[Flin Flon|Flin Flon, Canada]] was one of the largest point sources of [[Mercury (element)|mercury]] in North America in the 20th century.<ref name=":0">{{Cite journal |last1=Wiklund |first1=Johan A. |last2=Kirk |first2=Jane L. |last3=Muir |first3=Derek C.G. |last4=Evans |first4=Marlene |last5=Yang |first5=Fan |last6=Keating |first6=Jonathan |last7=Parsons |first7=Matthew T. |date=2017-05-15 |title=Anthropogenic mercury deposition in Flin Flon Manitoba and the Experimental Lakes Area Ontario (Canada): A multi-lake sediment core reconstruction |url=http://www.sciencedirect.com/science/article/pii/S0048969717302875|journal=Science of the Total Environment |volume=586 |pages=685–695 |doi=10.1016/j.scitotenv.2017.02.046 |pmid=28238379 |bibcode=2017ScTEn.586..685W |issn=0048-9697}}</ref><ref>{{Cite web |last=Naylor |first=Jonathon |title=When the smoke stopped: the shutdown of the Flin Flon smelter |url=http://www.thereminder.ca/news/local-news/when-the-smoke-stopped-the-shutdown-of-the-flin-flon-smelter-1.9955169 |access-date=2020-07-06|website=Flin Flon Reminder|date=21 February 2017 }}</ref> Even after smelter releases were drastically reduced, landscape [[Volatility (chemistry)|re-emission]] continued to be a major regional source of mercury. Lakes will likely receive mercury contamination from the smelter for decades, from both re-emissions returning as rainwater and [[Leaching (chemistry)|leaching]] of metals from the soil.<ref name=":0" />

===Air pollution===
Air pollutants generated by [[aluminium smelter]]s include [[carbonyl sulfide]], [[hydrogen fluoride]], [[polycyclic compound]]s, lead, [[nickel]], [[manganese]], [[polychlorinated biphenyl]]s, and [[Mercury (element)|mercury]].<ref>{{cite web |title=Primary Aluminum Reduction Industry |website= National Emission Standards for Hazardous Air Pollutants (NESHAP) |url=https://www.epa.gov/stationary-sources-air-pollution/primary-aluminum-reduction-industry-national-emission-standards |date=2022-05-25 |publisher=U.S. Environmental Protection Agency (EPA) |location=Washington, D.C.}}</ref> Copper smelter emissions include arsenic, [[beryllium]], [[cadmium]], [[chromium]], lead, manganese, and nickel.<ref>{{cite web |title=Primary Copper Smelting |website=NESHAP |url=https://www.epa.gov/stationary-sources-air-pollution/primary-copper-smelting-national-emissions-standards-hazardous-air |date=2022-02-01 |publisher=EPA}}</ref> Lead smelters typically emit arsenic, [[antimony]], cadmium and various lead compounds.<ref>{{cite web |title=Primary Lead Processing |website=NESHAP |url=https://www.epa.gov/stationary-sources-air-pollution/primary-lead-processing-national-emission-standards-hazardous-air |date=2022-04-07 |publisher=EPA}}</ref><ref>{{cite journal | title=Potentially toxic elements pollution in road deposited sediments around the active smelting industry of Korea| year=2021| pmc=8012626| last1=Jeong| first1=H.| last2=Choi| first2=J. Y.| last3=Ra| first3=K.| journal=Scientific Reports| volume=11| issue=1| page=7238| doi=10.1038/s41598-021-86698-x| pmid=33790361}}</ref><ref>{{cite journal | url=https://pubag.nal.usda.gov/catalog/7503323 | title=Heavy Metal Pollution Assessment in Stream Sediments from Urban and Different Types of Industrial Areas in South Korea| year=2021| doi=10.1080/15320383.2021.1893646| last1=Jeong| first1=Hyeryeong| last2=Choi| first2=Jin Young| last3=Ra| first3=Kongtae| journal=Soil and Sediment Contamination| volume=30| issue=7| pages=804–818| bibcode=2021SSCIJ..30..804J| s2cid=233818266}}</ref>
{{Expand section|Description of air pollution emissions and control options|date=September 2021}}

===Wastewater===
Wastewater pollutants discharged by iron and steel mills includes gasification products such as [[benzene]], [[naphthalene]], [[anthracene]], [[cyanide]], [[ammonia]], [[phenol]]s and [[cresol]]s, together with a range of more complex [[organic compound]]s known collectively as [[polycyclic aromatic hydrocarbon]]s (PAH).<ref name="EPA ironsteel">{{cite report |date=2002 |title=Development Document for Final Effluent Limitations Guidelines and Standards for the Iron and Steel Manufacturing Point Source Category |chapter=7. Wastewater Characterization |chapter-url=http://www.epa.gov/eg/iron-and-steel-manufacturing-effluent-guidelines-documents |publisher=EPA |pages=7–1ff |id=EPA 821-R-02-004}}</ref> Treatment technologies include recycling of wastewater; [[settling basin]]s, [[clarifier]]s and filtration systems for solids removal; [[oil skimmer]]s and filtration; [[chemical precipitation]] and filtration for dissolved metals; [[Adsorption#Activated carbon|carbon adsorption]] and biological oxidation for organic pollutants; and evaporation.<ref>{{cite report |title=Development Document for Effluent Limitations Guidelines, New Source Performance Standards and Pretreatment Standards for the Iron and Steel Manufacturing Point Source Category; Vol. I |url=https://www.epa.gov/eg/iron-and-steel-manufacturing-effluent-guidelines-documents |date=May 1982 |publisher=EPA |pages=177–216 |id=EPA 440/1-82/024a}}</ref>

Pollutants generated by other types of smelters varies with the base metal ore. For example, aluminum smelters typically generate [[fluoride]], [[benzo(a)pyrene]], antimony and nickel, as well as aluminum. Copper smelters typically discharge cadmium, lead, [[zinc]], arsenic and nickel, in addition to copper.<ref>EPA (1984). "Nonferrous Metals Manufacturing Point Source Category." ''Code of Federal Regulations,'' {{USCFR|40|421}}.</ref> Lead smelters may discharge [[antimony]], asbestos, cadmium, copper and zinc, in addition to lead.<ref>{{cite report |title=Development Document for Effluent Limitations Guidelines and Standards for the Nonferrous Metals Manufacturing Point Source Category; Volume IV |url=https://www.epa.gov/eg/nonferrous-metals-manufacturing-effluent-guidelines-documents-1990-amendment |date=May 1989 |publisher=EPA |pages=1711–1739 |id=EPA 440/1-89/019.4}}</ref>

===Health impacts===
Labourers working in the smelting industry have reported [[Respiratory disease|respiratory illnesses]] inhibiting their ability to perform the physical tasks demanded by their jobs.<ref>{{Cite journal |last=Sjöstrand |first=Torgny |date=1947-01-12 |title=Changes in the Respiratory Organs of Workmen at an Ore Smelting Works1 |journal=Acta Medica Scandinavica |volume=128 |issue=S196 |pages=687–699 |doi=10.1111/j.0954-6820.1947.tb14704.x |issn=0954-6820}}</ref>

===Regulations===
In the United States, the [[Environmental Protection Agency]] has published pollution control regulations for smelters.
* Air pollution standards under the [[Clean Air Act (United States)|Clean Air Act]]<ref>{{cite web |title=Clean Air Act Standards and Guidelines for the Metals Production Industry |url=https://www.epa.gov/stationary-sources-air-pollution/clean-air-act-standards-and-guidelines-metals-production-industry |date=2021-06-01 |publisher=EPA}}</ref>
* Water pollution standards ([[effluent guidelines]]) under the [[Clean Water Act]].<ref>{{cite web |title=Iron and Steel Manufacturing Effluent Guidelines |url=https://www.epa.gov/eg/iron-and-steel-manufacturing-effluent-guidelines |date=2021-07-13 |publisher=EPA}}</ref><ref>{{cite web |title=Nonferrous Metals Manufacturing Effluent Guidelines |url=https://www.epa.gov/eg/nonferrous-metals-manufacturing-effluent-guidelines |date=2021-07-13 |publisher=EPA}}</ref>
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