Remote hydrospheric

The physico-chemical properties of these POPs are illustrated in Fig. 2.2. APs and PFAs (hydrophilic substances) are relatively more water soluble than the legacy POPs, which suggests that these pollutants could easily reside in water column and then can be carried to remote areas by hydrospheric movement (Yamashita et al., 2005). 

The last two decades have seen some spectacular achievements in analytical science the placing of the environmental revolution on a sound basis by the routine determination of p.p.m. or p.p.b. levels of pollutants in the atmosphere, hydrosphere and biosphere the routine testing of athletes and race horses for traces of stimulants the remote analysis of the surface of the Moon and Mars and the atmosphere of Venus, etc. It has also been a period when the normal criteria for acceptable limits of impurities has dropped from the level of per cent to p.p.b., when non-destructive testing has become routine and when samples can be so small that even destructive methods of analysis scarcely have a deleterious effect on bulk of the material from which the sample is taken. In short, the nature of analysis has changed greatly. 

Martian (SNC) meteorites, remote sensing, and spacecraft exploration have provided insights into the origin, evolution and interaction of several light-element reservoirs on Mars including the lithosphere, hydrosphere and atmosphere. Beyond Earth, Mars is certainly the most exhaustively investigated body from a stable isotopic perspective. 

Carbon is highly important for our biosphere, not just because it forms organic compounds it also creates atmospheric greenhouse gases, pH buffers in seawater, and redox buffers virtually everywhere. Carbon species can stabilize metamorphic minerals and they can affect plutonism and volcanism. These various C constituents all interact via the biogeochemical C cycle, an array of C reservoirs linked by a network of physical, chemical and biological processes. The overall C cycle actually consists of multiple nested cyclic pathways that differ with respect to some of their reservoirs and processes (Fig. 1). However, all pathways ultimately pass through the hydrosphere and atmosphere, and it is this common course that unites the entire carbon cycle and allows even its most remote constituents to influence our environment and biosphere. 

The background concentration of lead in the lithosphere can be determined by analysing soils and rocks remote from sources of contamination and the mean level is probably in the range 10 to 20 ppm. The original uncontaminated levels in the atmosphere and hydrosphere cannot, of course, now be directly ascertained but estimates have been made of natural levels of 0.0005 yg/m in air, 0.5 ppb in fresh water and 0.02 to 0.04 ppb in ocean water [14] (p.l). 

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