Mercury (pollutant) - Revision history

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	[[Category:Done ~~2015~~-09-05]]		[[Category:Done 2018-12-10]]
			[[Category: Rudi grade Ashley edit]]
	[[File:MercuryFoodChain-01.png\|400px\|thumb\|Figure 1. Mercury often finds its way into water bodies and into small fish. Through the process of biomagnification, the concentrations of mercury rise to very toxic levels.<Ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/c/c5/MercuryFoodChain-01.png</ref> This makes shark and pike more hazardous to eat than canned tuna which is still more hazardous than salmon.]]		[[File:MercuryFoodChain-01.png\|400px\|thumb\|Figure 1. Mercury often finds its way into water bodies and into small fish. Through the process of biomagnification, the concentrations of mercury rise to very toxic levels.<Ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/c/c5/MercuryFoodChain-01.png</ref> This makes shark and pike more hazardous to eat than canned tuna which is still more hazardous than salmon.]]

	<onlyinclude>'''~~Mercury~~ (Hg) as a [[pollutant]]''' ~~is a major problem in [[pollution]] from [[energy]]~~. ~~It is released from both~~ humans and natural sources~~, with the~~ burning of [[coal]] ~~believed to be~~ a ~~major contributor~~.</onlyinclude> ~~Many sources put human [[emission]]s of mercury higher than natural sources, with humans contributing~~ anywhere from 50-90% of the mercury present in the [[environment]].<ref name=unep>United Nations Environment Programme. 2013. ''Global Mercury Assessment'' [Online] (Accessed July 22, 2015). Available: http://www.unep.org/PDF/PressReleases/GlobalMercuryAssessment2013.pdf</ref><ref name=hackett>G. Tyler Miller, Jr. and D. Hackett, "What is the threat from Mercury?," in ''Living in the Environment'', 2nd ed. USA: Nelson , 2011, ch.24, sec.8, pp.589-590</ref>		<onlyinclude>When the energy sector releases '''mercury (Hg) as a [[pollutant]]''', it creates environmental problems. Both humans and natural sources release mercury; burning [[coal]] specifically releases quite a bit of mercury.</onlyinclude> Human activity contribute anywhere from 50-90% of the mercury present in the [[environment]].<ref name=unep>United Nations Environment Programme. 2013. ''Global Mercury Assessment'' [Online] (Accessed July 22, 2015). Available: http://www.unep.org/PDF/PressReleases/GlobalMercuryAssessment2013.pdf</ref><ref name=hackett>G. Tyler Miller, Jr. and D. Hackett, "What is the threat from Mercury?," in ''Living in the Environment'', 2nd ed. USA: Nelson, 2011, ch.24, sec.8, pp.589-590</ref>

	The ~~reason this number varies so much is~~ because it is difficult to ~~determine~~ how much ~~mercury is~~ re-emitted ~~that~~ was ~~previously~~ emitted by humans. Re-emission occurs when previously ~~present~~ mercury is reintroduced into the environment by forest fires or other means, and requires complex modelling techniques to determine how much can be traced back to human emissions.<ref name=unep/>		The estimates are not more precise because it is difficult to figure out how much re-emitted mercury was initially emitted by humans. Re-emission occurs when previously stored mercury is reintroduced into the environment by forest fires or other means, and requires complex modelling techniques to determine how much can be traced back to human emissions.<ref name=unep/>

	==Emissions==		==Emissions==

	Mercury levels in the upper layers of oceans are much higher than they were in the past, ~~up around 2 times~~ what they were in the pre-industrial era. This is primarily ~~because of~~ human emissions, which rise into the atmosphere and fall out into soils and bodies of water.<ref name=unep/>		Mercury levels in the upper layers of oceans are much higher than they were in the past, at approximately double what they were in the pre-industrial era. This is caused primarily by human emissions, which rise into the atmosphere and fall out into soils and bodies of water.<ref name=unep/>

	Mercury is released naturally from rocks, soil, volcanoes, and by vaporization from the ocean.<Ref name=hackett/> This contributes to about 10% of the global input of mercury into the atmosphere.		Mercury is released naturally from rocks, soil, volcanoes, and by vaporization from the ocean.<Ref name=hackett/> This contributes to about 10% of the global input of mercury into the atmosphere.

	~~30% of the mercury emissions are directly attributed~~ to ~~human sources, which include~~ coal burning ~~as in [[coal-fired power plant]]s~~, mining and smelting, cement production, oil refining, ~~artisanal and~~ gold mining, and wastes from consumer products. Asia contributes to about half of the total human input of mercury ~~due to~~ the ~~large amount of~~ [[coal]] burning ~~they do~~ for ~~the production of~~ [[electricity]].<Ref name=unep/>		In addition to coal burning, humans emit mercury with mining and smelting, [[cement]] production, [[oil refinery\|oil refining]], gold mining, and wastes from consumer products. Asia contributes to about half of the total human input of mercury because of the extensive [[coal]] burning for [[electricity]].<Ref name=unep/>

	The largest emission source for mercury is re-~~emissions~~. This means that mercury that was previously deposited from the air onto soils, surface waters, and vegetation from past emissions can be emitted back into the air via forest fires or [[biomass]] burning. Mercury may be deposited and re-emitted many times as it cycles throughout the environment, ~~therefore once mercury is input it can cycle~~ ''indefinitely''.<ref name=unep/>		The largest emission source contributor for mercury is re-emission. This means that mercury that was previously deposited from the air onto soils, surface waters, and vegetation from past emissions can be emitted back into the air via forest fires or [[biomass]] burning. Mercury may be deposited and re-emitted many times as it cycles throughout the environment, potentially cycling ''indefinitely''.<ref name=unep/>

	'''Re-emitted mercury should not be considered a natural ~~source~~''', even though it may have originally ~~came~~ from a natural source. ~~The reason for this is that as~~ humans have introduced more mercury into the environment, re-emissions of mercury have also increased due to environmental burdens caused by the higher levels input.<ref name=unep/> Continuing to add to the mercury levels will result in ever increasing levels of re-emission, and even when human emissions are cut out completely this mercury could remain in the ~~cycle~~ for a long time. ~~Therefore~~ it is important that efforts to reduce ~~emissions continue and are strengthened~~.		'''Re-emitted mercury should not be considered natural in origin''', even though it may have originally come from a natural source. As humans have introduced more mercury into the environment, re-emissions of mercury have also increased due to environmental burdens caused by the higher levels of input.<ref name=unep/> Continuing to add to the mercury levels will result in ever increasing levels of re-emission, and even when human emissions are cut out completely, this mercury could remain in the system for a long time. This is why it is important that continued efforts are made to reduce mercury pollution.

	[[File:mercury emissions.png\|700px\|thumb\|center\|Figure 2. Emissions of mercury.<ref name=unep/>]]		[[File:mercury emissions.png\|700px\|thumb\|center\|Figure 2. Emissions of mercury.<ref name=unep/>]]
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	===Composition===		===Composition===

	Mercury itself is an [[element]], just like [[lead]] or [[arsenic]], and is classified as a heavy metal. It has many interesting characteristics which can be read about [[mercury (element)\|here]], some of which make it a very dangerous [[pollutant]]. In the [[atmosphere]], elemental mercury can either converted into more toxic inorganic compounds in which oxidized mercury (Hg<sup>2+</sup>) combines with other elements, or it can combine with [[carbon]] to form a worse contaminant known as methylmercury (CH<sub>3</sub>Hg).<Ref name=hackett/> These compounds may fall onto land or water ~~by rain or snow~~, or they may fall as dry particles and find their way into a lake or ocean.		Mercury itself is an [[element]], just like [[lead]] or [[arsenic]], and is classified as a heavy metal. It has many interesting characteristics (which can be read about [[mercury (element)\|here]]), some of which make it a very dangerous [[pollutant]]. In the [[atmosphere]], elemental mercury can either converted into more toxic inorganic compounds in which oxidized mercury (Hg<sup>2+</sup>) combines with other elements, or it can combine with [[carbon]] to form a worse contaminant known as methylmercury (CH<sub>3</sub>Hg).<Ref name=hackett/> These compounds may fall onto land or water through precipitation, or they may fall as dry particles and find their way into a lake or ocean.

	==Effects==		==Effects==
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	*Inhaling elemental mercury (Hg) or inorganic salts (Hg<sup>2+</sup>)		*Inhaling elemental mercury (Hg) or inorganic salts (Hg<sup>2+</sup>)

	The first is the largest contributor to human effects. Methylmercury is toxic and can cause extremely adverse effects when consumed, which ~~happens~~ when humans eat fish ~~that contain large concentrations of it~~. Through the process of [[biomagnification]] (see Figure 1) the concentration of methylmercury within fishes increases as one goes higher in the food chain. ~~It is therefore~~ dangerous to ~~eat~~ apex ~~predators and other top~~ predators such as those listed in Figure 1, especially for pregnant women and young children.<Ref name=hackett/>		The first is the largest contributor to human effects. Methylmercury is toxic and can cause extremely adverse effects when consumed, which can happen when humans eat highly contaminated fish. Through the process of [[biomagnification]] (see Figure 1) the concentration of methylmercury within fishes increases as one goes higher in the food chain. This makes it dangerous to consume top and apex predators such as those listed in Figure 1, and especially dangerous for pregnant women and young children to do so.<Ref name=hackett/>

	Effects of methylmercury can result in complex neurological problems, especially in young children and babies, ~~which affect~~ the brain and nervous system~~, potentially leading to~~ cerebral palsy, delayed onset of walking or talking, learning disabilities, tremors, irritability, impaired coordination and memory loss.<Ref name=hackett/> Pregnant mothers especially should not eat larger fish as their baby is vulnerable to these chemicals that attack developing organs.		Effects of methylmercury can result in complex neurological problems, especially in young children and babies, by affecting the brain and nervous system. Potential issues include: cerebral palsy, delayed onset of walking or talking, learning disabilities, tremors, irritability, impaired coordination and memory loss.<Ref name=hackett/> Pregnant mothers especially should not eat larger fish as their baby is vulnerable to these chemicals that attack developing organs.

	~~The effects of this substance when consumed~~ can be lethal. The largest first case of this was seen in Japan in 1956 in which thousands of people were killed. Mercury dumped from a chemical plant bioaccumulated in the fish and thousands of people were in turn affected by eating them.<ref name=pp>Pollution Probe. 2003. ''Mercury in the Environment''.</ref>		Mercury consumption can be lethal. The largest first case of this was seen in Japan in 1956 in which thousands of people were killed. Mercury dumped from a chemical plant bioaccumulated in the fish and thousands of people were in turn affected by eating them.<ref name=pp>Pollution Probe. 2003. ''Mercury in the Environment''.</ref>

	==Data Visualization==		==Data Visualization==

	The following data visualizations show the sources emitting mercury in Canada. The "Other" category contains all sources that are non-energy related; for a more in-depth look at mercury data, including a graph showing how mercury emissions have changed over time, click [~~http~~://energyeducation.ca/wiki/index.php?title=detailed_pollution_data&pollutant=Hg#Detailed_Source_Data here].		The following data visualizations show the sources emitting mercury in Canada. The "Other" category contains all sources that are non-energy related; for a more in-depth look at mercury data, including a graph showing how mercury emissions have changed over time, click [https://energyeducation.ca/wiki/index.php?title=detailed_pollution_data&pollutant=Hg#Detailed_Source_Data here].

	<html><iframe id='pollution-pie' class='data-visualization pollutant-Hg'></iframe></html>		<html><iframe id='pollution-pie' class='data-visualization pollutant-Hg'></iframe></html>

			==For Further Reading==
			*[[Periodic table of elements]]
			*[[Biomagnification]]
			*[[Pollution]]
			*[[Mercury (element)]]
			*Or explore a [[Special:Random\|random page]]

	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

J.williams: 1 revision imported

2015-08-26T21:31:21Z

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Jmdonev at 15:22, 26 August 2015

2015-08-26T15:22:06Z

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[[Category:Done 2015-09-05]]
[[File:MercuryFoodChain-01.png|400px|thumb|Figure 1. Mercury often finds its way into water bodies and into small fish. Through the process of biomagnification, the concentrations of mercury rise to very toxic levels.<Ref>Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/c/c5/MercuryFoodChain-01.png</ref> This makes shark and pike more hazardous to eat than canned tuna which is still more hazardous than salmon.]]

<onlyinclude>'''Mercury (Hg) as a [[pollutant]]''' is a major problem in [[pollution]] from [[energy]]. It is released from both humans and natural sources, with the burning of [[coal]] believed to be a major contributor.</onlyinclude> Many sources put human [[emission]]s of mercury higher than natural sources, with humans contributing anywhere from 50-90% of the mercury present in the [[environment]].<ref name=unep>United Nations Environment Programme. 2013. ''Global Mercury Assessment'' [Online] (Accessed July 22, 2015). Available: http://www.unep.org/PDF/PressReleases/GlobalMercuryAssessment2013.pdf</ref><ref name=hackett>G. Tyler Miller, Jr. and D. Hackett, "What is the threat from Mercury?," in ''Living in the Environment'', 2nd ed. USA: Nelson , 2011, ch.24, sec.8, pp.589-590</ref>

The reason this number varies so much is because it is difficult to determine how much mercury is re-emitted that was previously emitted by humans. Re-emission occurs when previously present mercury is reintroduced into the environment by forest fires or other means, and requires complex modelling techniques to determine how much can be traced back to human emissions.<ref name=unep/>

==Emissions==

Mercury levels in the upper layers of oceans are much higher than they were in the past, up around 2 times what they were in the pre-industrial era. This is primarily because of human emissions, which rise into the atmosphere and fall out into soils and bodies of water.<ref name=unep/>

Mercury is released naturally from rocks, soil, volcanoes, and by vaporization from the ocean.<Ref name=hackett/> This contributes to about 10% of the global input of mercury into the atmosphere.

30% of the mercury emissions are directly attributed to human sources, which include coal burning as in [[coal-fired power plant]]s, mining and smelting, cement production, oil refining, artisanal and gold mining, and wastes from consumer products. Asia contributes to about half of the total human input of mercury due to the large amount of [[coal]] burning they do for the production of [[electricity]].<Ref name=unep/>

The largest emission source for mercury is re-emissions. This means that mercury that was previously deposited from the air onto soils, surface waters, and vegetation from past emissions can be emitted back into the air via forest fires or [[biomass]] burning. Mercury may be deposited and re-emitted many times as it cycles throughout the environment, therefore once mercury is input it can cycle ''indefinitely''.<ref name=unep/>

'''Re-emitted mercury should not be considered a natural source''', even though it may have originally came from a natural source. The reason for this is that as humans have introduced more mercury into the environment, re-emissions of mercury have also increased due to environmental burdens caused by the higher levels input.<ref name=unep/> Continuing to add to the mercury levels will result in ever increasing levels of re-emission, and even when human emissions are cut out completely this mercury could remain in the cycle for a long time. Therefore it is important that efforts to reduce emissions continue and are strengthened.

[[File:mercury emissions.png|700px|thumb|center|Figure 2. Emissions of mercury.<ref name=unep/>]]

Mercury emissions have decreased drastically in recent years ([[detailed pollution data#Time Series Data|click here]] and select "Mercury"), however small amounts of mercury can still be considered toxic in foods. There are limits placed on how much [[methylmercury]] can be contained within food before it is contaminated. For example, the limit for young children in Canada is 0.2 [[gram|micrograms]] per kilogram of body weight per day.<ref name=pp/> So if a child that weighs 20 kilograms ingests just 4 micrograms (an extremely small amount) in a day, they would be considered to have exceeded the maximum dose. '''An analogy:''' if a 1 gram paperclip were made entirely of methylmercury and you cut it into 250 000 pieces, only ''one'' of these pieces would be required for this toxic dose!

===Composition===

Mercury itself is an [[element]], just like [[lead]] or [[arsenic]], and is classified as a heavy metal. It has many interesting characteristics which can be read about [[mercury (element)|here]], some of which make it a very dangerous [[pollutant]]. In the [[atmosphere]], elemental mercury can either converted into more toxic inorganic compounds in which oxidized mercury (Hg<sup>2+</sup>) combines with other elements, or it can combine with [[carbon]] to form a worse contaminant known as methylmercury (CH<sub>3</sub>Hg).<Ref name=hackett/> These compounds may fall onto land or water by rain or snow, or they may fall as dry particles and find their way into a lake or ocean.

==Effects==

Humans are exposed to mercury in 2 ways:<ref name=hackett/>

*Eating fish contaminated with organic methylmercury.
*Inhaling elemental mercury (Hg) or inorganic salts (Hg<sup>2+</sup>)

The first is the largest contributor to human effects. Methylmercury is toxic and can cause extremely adverse effects when consumed, which happens when humans eat fish that contain large concentrations of it. Through the process of [[biomagnification]] (see Figure 1) the concentration of methylmercury within fishes increases as one goes higher in the food chain. It is therefore dangerous to eat apex predators and other top predators such as those listed in Figure 1, especially for pregnant women and young children.<Ref name=hackett/>

Effects of methylmercury can result in complex neurological problems, especially in young children and babies, which affect the brain and nervous system, potentially leading to cerebral palsy, delayed onset of walking or talking, learning disabilities, tremors, irritability, impaired coordination and memory loss.<Ref name=hackett/> Pregnant mothers especially should not eat larger fish as their baby is vulnerable to these chemicals that attack developing organs.

The effects of this substance when consumed can be lethal. The largest first case of this was seen in Japan in 1956 in which thousands of people were killed. Mercury dumped from a chemical plant bioaccumulated in the fish and thousands of people were in turn affected by eating them.<ref name=pp>Pollution Probe. 2003. ''Mercury in the Environment''.</ref>

==Data Visualization==

The following data visualizations show the sources emitting mercury in Canada. The "Other" category contains all sources that are non-energy related; for a more in-depth look at mercury data, including a graph showing how mercury emissions have changed over time, click [http://energyeducation.ca/wiki/index.php?title=detailed_pollution_data&pollutant=Hg#Detailed_Source_Data here].

<html><iframe id='pollution-pie' class='data-visualization pollutant-Hg'></iframe></html>

==References==
{{reflist}}
[[Category:Uploaded]]