Global distillation

Global distillation or the grasshopper effect is the geochemical process by which certain chemicals, most notably persistent organic pollutants (POPs), are transported from warmer to colder regions of the Earth, particularly the poles and mountain tops. Global distillation explains why relatively high concentrations of POPs have been found in the Arctic environment and in the bodies of animals and people who live there, even though most of the chemicals have not been used in the region in appreciable amounts.[1]

## Contents

* 1 Mechanism
* 2 Effect of global distillation
* 3 See also
* 4 References
* 5 Further reading
* 6 External links

## Mechanism

The global distillation process can be understood using the same principles that explain distillations used to make liquor or purify chemicals in a laboratory. In these processes, a substance is vapourised at a relatively high temperature, and then the vapour travels to an area of lower temperature where it condenses. A similar phenomenon occurs on a global scale for certain chemicals. When these chemicals are released into the environment, some evaporates when ambient temperatures are warm, blows around on winds until temperatures are cooler, and then condensation occurs. Drops in temperature large enough to result in deposition can occur when chemicals are blown from warmer to cooler climates, or when seasons change. The net effect is atmospheric transport from low to high latitude and altitude. Since global distillation is a relatively slow process that relies on successive evaporation/condensation cycles, it is only effective for semi-volatile chemicals that break down very slowly in the environment, like DDT, polychlorinated biphenyls, and lindane.

## Effect of global distillation

Several studies have measured the effect, usually by correlating the concentrations of a certain chemical in air, water, or biological specimens from various parts of the world with the latitude from which the samples were collected. For example, the levels of PCBs, hexachlorobenzene, and lindane measured in water, lichens, and tree bark have been shown to be greater in higher latitudes.[2]

The effect is also used to explain why certain pesticides are found in Arctic and high altitude samples even though there is no agricultural activity in these areas,[3] and why indigenous peoples of the Arctic have some of the highest body burdens of certain POPs ever measured. Recent studies conclude that for most pollutants slower degradation in colder temperatures is a more important factor in accounting for their accumulation in cold region than global distillation. Exceptions include highly volatile, persistent substances such as chlorofluorocarbons.[4][5]

## See also

* Stockholm Convention

## References

1. ↑ "Ridding the world of POPs: A guide to the Stockholm Convention on Persistent Organic Pollutants". United Nations Environment Programme. April 2005. http://chm.pops.int/Portals/0/Repository/CHM-general/UNEP-POPS-CHM-GUID-RIDDING.English.PDF.
2. ↑ Simonich SL, Hites RA (September 1995). "Global distribution of persistent organochlorine compounds". Science 269 (5232): 1851–4. doi:10.1126/science.7569923. PMID 7569923. Bibcode: 1995Sci...269.1851S.
3. ↑ "Western Airborne Contaminants Project - Results". 2008. https://www.nature.nps.gov/air/Studies/air_toxics/docs/2008FinalReport/08_FactSheet_LoRes_smIm_letter.pdf.
4. ↑ Schenker, Scheringer, Hungerbühler: Do Persistent Organic Pollutants reach a thermodynamic equilibrium in the global environment? Environmental Science & Technology, 2014, doi:10.1021/es405545w.
5. ↑ Fabio Bergamin: The result of slow degradation, ETH News, 2014.

## Further reading

* Cone, Marla (2006). Silent Snow: The Slow Poisoning of The Arctic. Grove Press. ISBN 0-8021-4259-1. https://archive.org/details/isbn_9780802142597.

## External links

* The Grasshopper Effect and Tracking Hazardous Air Pollutants, Environment Canada.

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Pollution

Air pollution|

* Acid rain
* Air quality index
* Atmospheric dispersion modeling
* Chlorofluorocarbon
* Indoor air quality
* Global dimming
* Global distillation
* Global warming
* Ozone depletion
* Atmospheric particulate matter
* Smog

Water pollution|

* Environmental impact of pharmaceuticals and personal care products
* Environmental impact of shipping
* Environmental monitoring
* Eutrophication
* Freshwater environmental quality parameters
* Groundwater pollution
* Hypoxia
* Marine debris
* Marine pollution
* Nutrient pollution
* Ocean acidification
* Oil spill
* Septic tank
* Surface runoff
* Thermal pollution
* Turbidity
* Urban runoff
* Wastewater
* Water quality
* Water stagnation
* Waterborne diseases

Soil contamination|

* Bioremediation
* Electrical resistance heating
* Herbicide
* Open defecation
* Pesticide
* Phytoremediation
* Soil Guideline Values (SGVs)

Radioactive contamination|

* Actinides in the environment
* Bioremediation of radioactive waste
* Environmental radioactivity
* Fission product
* Nuclear fallout
* Plutonium in the environment
* Radiation poisoning
* Radium in the environment
* Uranium in the environment

Other types of pollution|

* Land degradation
* Light pollution
* Pollution from nanomaterials
* Noise pollution
* Radio spectrum pollution
* Urban heat island
* Visual pollution

Pollution response|

* Cleaner production
* Industrial ecology
* Pollutant release and transfer register
* Polluter pays principle
* Pollution control
* Pollution prevention
* Waste minimization
* Zero waste

Inter-government treaties|

* Basel Convention
* CLRTAP
* Kyoto Protocol
* MARPOL Convention
* Montreal Protocol
* OSPAR
* Rotterdam Convention
* Stockholm Convention

Major organizations|

* Basel Action Network
* Central Pollution Control Board (India)
* DEFRA
* Environment Agency (England)
* Scottish Environment Protection Agency
* U.S. EPA
* European Environment Agency
* Greenpeace

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