Mercury cycle

Last updated

Physical mercury cycle PhysicalMercuryCycle.png
Physical mercury cycle

The mercury cycle is a biogeochemical cycle influenced by natural and anthropogenic processes that transform mercury through multiple chemical forms and environments.

Contents

Mercury is present in the Earth's crust and in various forms on the Earth's surface. It can be elemental, inorganic, or organic. [1] Mercury exists in three oxidation states: 0 (elemental mercury), I (mercurous mercury), and II (mercuric mercury).

Mercury emissions to the atmosphere can be primary sources, which release mercury from the lithosphere, or secondary sources, which exchange mercury between surface reservoirs. [2] Annually, over 5000 metric tons of mercury is released to the atmosphere by primary emissions and secondary re-emissions. [3]

Sources of mercury

Sample of the mercury sulfide ore, cinnabar Cinnabar (New Almaden, California, USA) (18824306236).jpg
Sample of the mercury sulfide ore, cinnabar

Primary sources

Primary sources of mercury emissions can be natural or anthropogenic. [4] Most natural mercury occurs as the mercury sulfide mineral, cinnabar, which is one of the only significant ores of mercury. [5] [6] Organic-rich sedimentary rocks can also contain elevated mercury. Weathering of minerals and geothermal activity release mercury to the environment. [7] [8] Active volcanoes are another significant primary source of natural mercury. [9] Anthropogenic primary sources of mercury include gold mining, burning coal, and production of non-iron metals, such as copper or lead. [8] [10]

Secondary sources

Secondary natural sources, which re-emit previously deposited mercury, include vegetation, evasion from oceans and lakes, and biomass burning, including forest fires. [3] Primary anthropogenic emissions are leading to increased sizes of mercury in surface reservoirs. [11]

Processes

Mercury is transported and distributed by atmospheric circulation, which moves elemental mercury from the land to the ocean. [12] Elemental mercury in the atmosphere is returned to the Earth's surface by several routes. A major sink of elemental mercury (Hg(0)) in the atmosphere is through dry deposition. [13] Some of elemental mercury, on the other hand, is photooxidized to gaseous mercury(II), and is returned to the Earth's surface by both dry and wet deposition. [14] Because photooxidation is very slow, elemental mercury can circulate over the entire globe before being oxidized and deposited. [14] Wet and dry deposition is responsible for 90% of the mercury of surface waters, including open ocean. [15] [16]

A fraction of deposited mercury instantaneously re-volatilize back to the atmosphere. [17]

Inorganic mercury can be converted by bacteria and archaea into methylmercury ([CH3 Hg] +), [18] which bioaccumulates in marine species such as tuna and swordfish and biomagnifies further up the food chain. [19] [20]

Certain xenophyophores have been found to have abnormally high concentrations of mercury within their bodies. [21]

See also

Related Research Articles

<span class="mw-page-title-main">Carbon cycle</span> Natural processes of carbon exchange

The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many rocks such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks.

<span class="mw-page-title-main">Nitrogen cycle</span> Biogeochemical cycle by which nitrogen is converted into various chemical forms

The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmospheric nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems.

<span class="mw-page-title-main">Biogeochemical cycle</span> Chemical transfer pathway between Earths biological and non-biological parts

A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by living organisms and through various geological forms and reservoirs, including the atmosphere, the soil and the oceans. It can be thought of as the pathway by which a chemical substance cycles the biotic compartment and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, lithosphere and hydrosphere.

<span class="mw-page-title-main">Oxygen cycle</span> Biogeochemical cycle of oxygen

Oxygen cycle refers to the movement of oxygen through the atmosphere (air), biosphere (plants and animals) and the lithosphere (the Earth’s crust). The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used. The oxygen cycle is the biogeochemical cycle of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. The word oxygen in the literature typically refers to the most common oxygen allotrope, elemental/diatomic oxygen (O2), as it is a common product or reactant of many biogeochemical redox reactions within the cycle. Processes within the oxygen cycle are considered to be biological or geological and are evaluated as either a source (O2 production) or sink (O2 consumption).

<span class="mw-page-title-main">Methylmercury</span> Toxic chemical compound

Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula [CH3Hg]+. It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a bioaccumulative environmental toxicant with a 50-day half-life. Methylmercury is the causative agent of the infamous Minamata disease.

<span class="mw-page-title-main">Iron cycle</span> Biogeochemical cycle of Fe2+/Fe3+

The iron cycle (Fe) is the biogeochemical cycle of iron through the atmosphere, hydrosphere, biosphere and lithosphere. While Fe is highly abundant in the Earth's crust, it is less common in oxygenated surface waters. Iron is a key micronutrient in primary productivity, and a limiting nutrient in the Southern ocean, eastern equatorial Pacific, and the subarctic Pacific referred to as High-Nutrient, Low-Chlorophyll (HNLC) regions of the ocean.

<span class="mw-page-title-main">Arctic methane emissions</span> Release of methane in the Arctic

Arctic methane emissions contribute to a rise in methane concentrations in the atmosphere. Whilst the Arctic region is one of many natural sources of the greenhouse gas methane, there is nowadays also a human component to this due to the effects of climate change. In the Arctic, the main human-influenced sources of methane are thawing permafrost, Arctic sea ice melting, clathrate breakdown and Greenland ice sheet melting. This methane release results in a positive climate change feedback, as methane is a powerful greenhouse gas. When permafrost thaws due to global warming, large amounts of organic material can become available for methanogenesis and may therefore be released as methane.

Marine chemistry, also known as ocean chemistry or chemical oceanography, is the study of the chemical composition and processes of the world’s oceans, including the interactions between seawater, the atmosphere, the seafloor, and marine organisms. This field encompasses a wide range of topics, such as the cycling of elements like carbon, nitrogen, and phosphorus, the behavior of trace metals, and the study of gases and nutrients in marine environments. Marine chemistry plays a crucial role in understanding global biogeochemical cycles, ocean circulation, and the effects of human activities, such as pollution and climate change, on oceanic systems. It is influenced by plate tectonics and seafloor spreading, turbidity, currents, sediments, pH levels, atmospheric constituents, metamorphic activity, and ecology.

<span class="mw-page-title-main">Mercury regulation in the United States</span>

Mercury regulation in the United States limit the maximum concentrations of mercury (Hg) that is permitted in air, water, soil, food and drugs. The regulations are promulgated by agencies such as the Environmental Protection Agency (EPA) and Food and Drug Administration (FDA), as well as a variety of state and local authorities. EPA published the Mercury and Air Toxics Standards (MATS) regulation in 2012; the first federal standards requiring power plants to limit emissions of mercury and other toxic gases.

<span class="mw-page-title-main">Oceanic carbon cycle</span> Ocean/atmosphere carbon exchange process

The oceanic carbon cycle is composed of processes that exchange carbon between various pools within the ocean as well as between the atmosphere, Earth interior, and the seafloor. The carbon cycle is a result of many interacting forces across multiple time and space scales that circulates carbon around the planet, ensuring that carbon is available globally. The Oceanic carbon cycle is a central process to the global carbon cycle and contains both inorganic carbon and organic carbon. Part of the marine carbon cycle transforms carbon between non-living and living matter.

<span class="mw-page-title-main">Marine mercury pollution</span> Mercury contamination in sea and sediments

Mercury is a heavy metal that cycles through the atmosphere, water, and soil in various forms to different parts of the world. Due to this natural mercury cycle, irrespective of which part of the world releases mercury it could affect an entirely different part of the world making mercury pollution a global concern. Mercury pollution is now identified as a global problem and awareness has been raised on an international action plan to minimize anthropogenic mercury emissions and clean up mercury pollution. The 2002 Global Mercury Assessment concluded that "International actions to address the global mercury problem should not be delayed". Among many environments that are under the impact of mercury pollution, the ocean is one which cannot be neglected as it has the ability to act as a "storage closet" for mercury. According to a recent model study the total anthropogenic mercury released into the ocean is estimated to be around 80,000 to 45,000 metric tons and two-thirds of this amount is estimated to be found in waters shallower than 1000m level where much consumable fish live. Mercury can bioaccumulate in marine food chains in the form of highly toxic methylmercury which can cause health risks to human seafood consumers. According to statistics, about 66% of global fish consumption comes from the ocean. Therefore, it is important to monitor and regulate oceanic mercury levels to prevent more and more mercury from reaching the human population through seafood consumption.

<span class="mw-page-title-main">Marine biogeochemical cycles</span>

Marine biogeochemical cycles are biogeochemical cycles that occur within marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. These biogeochemical cycles are the pathways chemical substances and elements move through within the marine environment. In addition, substances and elements can be imported into or exported from the marine environment. These imports and exports can occur as exchanges with the atmosphere above, the ocean floor below, or as runoff from the land.

Caroline Masiello is a biogeochemist who develops tools to better understand the cycling and fate of globally relevant elemental cycles. She is a professor at Rice University in the Department of Earth, Environmental and Planetary Sciences and holds joint appointments in the Chemistry and Biochemistry Departments. Masiello was elected as a Fellow of the Geological Society of America in 2017. She currently leads an interdisciplinary team of scientists who are developing microbial sensors for earth system science.

<span class="mw-page-title-main">Aluminum cycle</span>

Aluminum is the third most abundant element in the lithosphere at 82,000 ppm. It occurs in low levels, 0.9 ppm, in humans. Aluminum is known to be an ecotoxicant and expected to be a health risk to people. Global primary production (GPP) of aluminum was about 52 million tons in 2013 and remains one of the world's most important metals. It is used for infrastructure, vehicles, aviation, energy and more due to its lightweight, ductility, and cheap cost. Aluminum is harvested from gibbsite, boehmite, and diaspore which make up bauxite. The aluminum cycle is the biogeochemical cycle by which aluminum is moved through the environment by natural and anthropogenic processes. The biogeochemical cycle of aluminum is integral with silicon and phosphorus. For example, phosphates store aluminum that has been sedimented and aluminum is found in diatoms. Aluminum has been found to prevent growth in organisms by making phosphates less available. The humans/lithosphere ratio (B/L) is very low at 0.000011. This level shows that aluminum is more essential in the lithospheric cycle than in the biotic cycle.

<span class="mw-page-title-main">Elsie Sunderland</span> American scientist

Elsie M. Sunderland is a Canadian toxicologist and environmental scientist and the Gordon McKay Professor of Environmental Chemistry at Harvard University. She studies processes through which human activities increase and modify pollutants in natural ecosystems and living systems.

<span class="mw-page-title-main">Boron cycle</span> Biogeochemical cycle

The boron cycle is the biogeochemical cycle of boron through the atmosphere, lithosphere, biosphere, and hydrosphere.

<span class="mw-page-title-main">Arsenic cycle</span>

The arsenic (As) cycle is the biogeochemical cycle of natural and anthropogenic exchanges of arsenic terms through the atmosphere, lithosphere, pedosphere, hydrosphere, and biosphere. Although arsenic is naturally abundant in the Earth's crust, long-term exposure and high concentrations of arsenic can be detrimental to human health.

<span class="mw-page-title-main">Chlorine cycle</span>

The chlorine cycle (Cl) is the biogeochemical cycling of chlorine through the atmosphere, hydrosphere, biosphere, and lithosphere. Chlorine is most commonly found as inorganic chloride ions, or a number of chlorinated organic forms. Over 5,000 biologically produced chlorinated organics have been identified.

<span class="mw-page-title-main">Lead cycle</span>

The lead cycle is the biogeochemical cycle of lead through the atmosphere, lithosphere, biosphere, and hydrosphere, which has been influenced by anthropogenic activities.

<span class="mw-page-title-main">Fluorine cycle</span> Biogeochemical cycle

The fluorine cycle is the series of biogeochemical processes through which fluorine moves through the lithosphere, hydrosphere, atmosphere, and biosphere. Fluorine originates from the Earth’s crust, and its cycling between various sources and sinks is modulated by a variety of natural and anthropogenic processes.

References

  1. ↑ "Mercury and health". www.who.int. Retrieved April 10, 2019.
  2. ↑ Beckers F, Rinklebe J (May 3, 2017). "Cycling of mercury in the environment: Sources, fate, and human health implications: A review". Critical Reviews in Environmental Science and Technology. 47 (9): 693–794. Bibcode:2017CREST..47..693B. doi:10.1080/10643389.2017.1326277. ISSN   1064-3389. S2CID   99877193.
  3. 1 2 Pirrone N, Cinnirella S, Feng X, Finkelman RB, Friedli HR, Leaner J, Mason R, Mukherjee AB, Stracher GB, Streets DG, Telmer K (July 2, 2010). "Global mercury emissions to the atmosphere from anthropogenic and natural sources". Atmospheric Chemistry and Physics. 10 (13): 5951–5964. Bibcode:2010ACP....10.5951P. doi: 10.5194/acp-10-5951-2010 . ISSN   1680-7324.
  4. ↑ US EPA, OITA (February 27, 2014). "Mercury Emissions: The Global Context". US EPA. Retrieved October 20, 2020.
  5. ↑ "Cinnabar: A toxic ore of mercury, once used as a pigment". geology.com. Retrieved April 12, 2019.
  6. ↑ Rytuba JJ (August 2, 2002). "Mercury from mineral deposits and potential environmental impact". Environmental Geology . 43 (3): 326–338. doi:10.1007/s00254-002-0629-5. S2CID   127179672.
  7. ↑ Bagnato E, Aiuppa A, Parello F, Allard P, Shinohara H, Liuzzo M, Giudice G (2011). "New clues on the contribution of Earth's volcanism to the global mercury cycle". Bulletin of Volcanology. 73 (5): 497–510. Bibcode:2011BVol...73..497B. doi:10.1007/s00445-010-0419-y. ISSN   0258-8900. S2CID   129282620.
  8. 1 2 Xu J, Bravo AG, Lagerkvist A, Bertilsson S, Sjöblom R, Kumpiene J (January 2015). "Sources and remediation techniques for mercury contaminated soil". Environment International. 74: 42–53. Bibcode:2015EnInt..74...42X. doi:10.1016/j.envint.2014.09.007. PMID   25454219.
  9. ↑ Geyman, BM, Thackray, CP, Jacob, DJ, Sunderland, EM (2023). "Impacts of volcanic emissions on the global biogeochemical mercury cycle: Insights from satellite observations and chemical transport modeling". Geophysical Research Letters. 50 (21): e2023GRL104667. Bibcode:2023GeoRL..5004667G. doi: 10.1029/2023GL104667 .
  10. ↑ Horowitz HM, Jacob DJ, Amos HM, Streets DG, Sunderland EM (September 2014). "Historical Mercury releases from commercial products: global environmental implications". Environmental Science & Technology. 48 (17): 10242–50. Bibcode:2014EnST...4810242H. doi:10.1021/es501337j. PMID   25127072. S2CID   17320659.
  11. ↑ "Global Mercury Assessment 2013: Sources, Emissions, Releases and Environmental Transport" (PDF). United Nations Environment Programme. 2013. hdl:20.500.11822/7984. Archived from the original (PDF) on October 21, 2019.
  12. ↑ Boening DW (2000). "Ecological effects, transport, and fate of mercury: a general review". Chemosphere. 40 (12): 1335–1351. Bibcode:2000Chmsp..40.1335B. doi:10.1016/S0045-6535(99)00283-0. PMID   10789973.
  13. ↑ Driscoll CT, Mason RP, Chan HM, Jacob DJ, Pirrone N (May 2013). "Mercury as a global pollutant: sources, pathways, and effects". Environmental Science & Technology. 47 (10): 4967–83. Bibcode:2013EnST...47.4967D. doi:10.1021/es305071v. PMC   3701261 . PMID   23590191.
  14. 1 2 Morel FM, Kraepiel AM, Amyot M (1998). "The chemical cycle and bioaccumulation of mercury". Annual Review of Ecology and Systematics. 29 (1): 543–566. doi:10.1146/annurev.ecolsys.29.1.543. ISSN   0066-4162. S2CID   86336987.
  15. ↑ Mason RP, Fitzgerald WF, Morel FM (1994). "The biogeochemical cycling of elemental mercury: Anthropogenic influences". Geochimica et Cosmochimica Acta. 58 (15): 3191–3198. Bibcode:1994GeCoA..58.3191M. doi:10.1016/0016-7037(94)90046-9.
  16. ↑ Leopold K, Foulkes M, Worsfold P (March 2010). "Methods for the determination and speciation of mercury in natural waters--a review". Analytica Chimica Acta. 663 (2): 127–38. Bibcode:2010AcAC..663..127L. doi:10.1016/j.aca.2010.01.048. PMID   20206001.
  17. ↑ Selin NE (2009). "Global Biogeochemical Cycling of Mercury: A Review". Annual Review of Environment and Resources. 34 (1): 43–63. doi: 10.1146/annurev.environ.051308.084314 . ISSN   1543-5938.
  18. ↑ Gilmour CC, Podar M, Bullock AL, Graham AM, Brown SD, Somenahally AC, Johs A, Hurt RA, Bailey KL, Elias DA (October 2013). "Mercury methylation by novel microorganisms from new environments". Environmental Science & Technology. 47 (20): 11810–20. Bibcode:2013EnST...4711810G. doi:10.1021/es403075t. PMID   24024607.
  19. ↑ "Mercury: Overview". Oceana. Oceana: Protecting the World's Oceans. 2012. Archived from the original on January 4, 2015. Retrieved February 28, 2012.
  20. ↑ Schartup AT, Balcom PH, Mason RP (January 2014). "Sediment-porewater partitioning, total sulfur, and methylmercury production in estuaries". Environmental Science & Technology. 48 (2): 954–60. Bibcode:2014EnST...48..954S. doi:10.1021/es403030d. PMC   4074365 . PMID   24344684.
  21. ↑ Gooday AJ, Sykes D, Góral T, Zubkov MV, Glover AG (August 2018). "Micro-CT 3D imaging reveals the internal structure of three abyssal xenophyophore species (Protista, Foraminifera) from the eastern equatorial Pacific Ocean". Scientific Reports. 8 (1): 12103. Bibcode:2018NatSR...812103G. doi:10.1038/s41598-018-30186-2. PMC   6092355 . PMID   30108286.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.