Grasshopper effect

Semeena VS, Lammel G (2005) Significance of the grasshopper effect on the atmospheric distribution of persistent organic substances. Geophysical Research Letters 32 Senthilkumar K, Ohi E, Sajwan K, Takasuga T, Kannan K (2007) Perfluorinated compounds in river water, river sediment, market fish, and wildlife samples from japan. Bull of Environ Contain Toxicol 79 427 131... 

On a worldwide basis, toxic concentrations of the heavy metals have thus far been limited to industrialized harbors. The only metals that appear to have accumulated to toxic levels on a regional scale are mercury, cadmium, and lead in the Arctic Ocean. This concentration of mercury and lead has been fecilitated by a natural process, called the grasshopper effect, which acts to transport volatile compoimds poleward. This transport plays a major role in redistributing the volatile organic pollutants, such as the PCBs, and, hence, is discussed at further length in Chapter 26.7. The process responsible for the cadmium enrichment in the Arctic appears to involve low-altitude transport of the fine particles that compose Arctic haze. 

Gouin T, Mackay D, Jones KC, Harner T, Meijer SN. 2004. Evidence for the grasshopper effect and fractionation during long-range atmospheric transport of organic contaminants. Environ Pollut 128 139-148. 

All the three groups of SVOCs concerned in this paper, namely PCBs, PBDEs and PAHs, are persistent and semi-volatile and subject to atmospheric transport to remote locations, through a series of deposition/volatilization hops, known as the grasshopper effect. As a result, these compounds have been detected in the Arctic and Antarctic samples in numerous studies. The major factors determining the long-range transport potential (LRTP) are the volatihty and the degradation rate, or half life of the SVOCs in the atmosphere. 

The Global Distillation Model, also called the Grasshopper Effect and the Cold-Condensation Effect, predicts a global fractionation of these chemicals will occur whereby more... 

Grasshopper effect Progressive evaporation of chemicals from warmer environments toward colder environments in high latitudes and high altitudes. 

In temperate regions, mercury speciation processes are important as they facilitate the movement of mercury to Polar Regions in a process referred to as the Grasshopper Effect (Fig. 2). Elemental mercury transport has erroneously... 

Figure 2 Movement of mercury to the Polar Regions by the grasshopper effect ...

The effects of climate change on the speciation and fate of mercury in Polar ecosystems is particularly important. Not only is mercury increasing in the atmosphere but atmospheric deposition will be favored in colder climates due to changes in atmospheric redox chemistry. This means that mercury released in equatorial areas will undergo a global distillation via a process similar to the grasshopper effect observed with semi-volatUe organic pollutants. 

HCB tends to sorb to soil rather than remain in water or air (Figure 4.2) but has a relatively high vapor pressure. It degrades slowly. Consequently HCB released to the environment will persist and a large amount of the mass may be transported long distances by air. (See Table 4.3 for relevant model results.) Remember the "grasshopper effect" described in Chapter 2 This effect accounts for the airborne movement of HCB from the countries where it was manufactured and used toward the poles of the earth [91,92]. 

The actual transport of pollutants is considerably more complex. One mechanism, termed the grasshopper effect, consists of the repeated precipitation of the pollutant from the atmosphere and its revolatization. The simple model we provided here does not take these details into accoxmt. It does, however, set an upper limit to what can be expected if the emissions persist. This is important and useful information. 

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