global distillation 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. part of a series onpollutionair pollution from a factory air acid rain air quality index atmospheric dispersion modeling chlorofluorocarbon exhaust gas haze indoor air internal combustion engine global dimming global distillation ozone depletion particulates persistent organic pollutant smog aerosol soot volatile organic compound biological biological hazard genetic introduced species (invasive species) digital information electromagnetic light ecological overillumination radio spectrum natural ozone radium and radon in the environment volcanic ash wildfire noise transportation land water air rail sustainable transport urban sonar marine mammals and sonar industrial military abstract noise control radiation actinides bioremediation depleted uranium nuclear fission nuclear fallout plutonium poisoning radioactivity uranium electromagnetic radiation and health radioactive waste soil agricultural herbicides manure waste pesticides land degradation bioremediation defecation electrical resistance heating soil guideline values phytoremediation solid waste biodegradable waste brown waste electronic waste battery recycling food waste green waste hazardous waste biomedical waste chemical waste construction waste lead poisoning mercury poisoning toxic waste international waste industrial waste lead smelting litter mining coal mining gold mining surface mining deep sea mining mining waste uranium mining municipal solid waste garbage nanomaterials plastic microplastics packaging waste post-consumer waste waste management landfill thermal treatment space satellite thermal urban heat island visual air travel advertising clutter overhead power lines traffic signs vandalism war chemical warfare herbicidal warfare (agent orange) nuclear holocaust (nuclear fallout - nuclear famine - nuclear winter) scorched earth unexploded ordnance war and environmental law water agricultural wastewater diseases eutrophication firewater freshwater groundwater hypoxia industrial wastewater marine debris monitoring nonpoint source see misc section nutrient ocean acidification oil spill pharmaceuticals freshwater salinization septic tanks sewage septic tanks pit latrine shipping stagnation sulfur water surface runoff turbidity urban runoff water quality misc point source area source legacy pollution lists diseases law by country most polluted cities least polluted cities by pm2.5 treaties categories by country environment portal ecology portal 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. 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, 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.