Global atmosphere metals, emission

Table 3. Global heavy metals emissions into atmosphere and oceans (1(P tons per year).

In this discussion of heavy metals, geochemical cycles are treated in a simple manner emissions from land and oceans to the global atmosphere and subsequent deposition on the land and ocean surface, and runoff from the land to the ocean and eventual deposition in marine sediments. Only two components of this simple cycle will be discussed due to the availability of relatively accurate... 

TIMS has been used in the past few decades for the analysis of heavy metals in polar snow and ice of Antarctica and Greenland (11, 49-53, 66, 67). It is in fact an absolute technique, whose results can give not only the total concentration of the metal with unrivalled accuracy and precision, but also quantify the isotopic composition of the analyte. This last feature constitutes a precious tool for probing the sources of emission of heavy metals (e.g., Pb) to the global atmosphere throughout the centuries. 

Pacyna JM and Pacyna E (2001) An assessment of global and regional emissions of trace metals to the atmosphere from anthropogenic sources worldwide. Environ Rev 9 269-298. 

Table 5 Emissions of some metals to the global atmosphere...

Fig. 4 Global metal emissions to the atmosphere by region (tonnes/year) for arsenic (As), cadmium (Cd), mercury (Hg) and molybdenum (Mo) (a) chromium (Cr), copper (Cu) and manganese Mn (b) nickel (Ni), lead (Pb), vanadium (V) and zinc (Zn) (c) and antimony (Sb), selenium (Se), tin (Sn) and thallium (Tl) (d) (data from Pacyna and Pacyna 2001)...

Cadmium (Cd) anode cells are at present manufactured based on nickel-cadmium, silver-cadmium, and mercury-cadmium couples. Thus wastewater streams from cadmium-based battery industries carry toxic metals cadmium, nickel, silver, and mercury, of which Cd is regarded the most hazardous. It is estimated that globally, manufacturing activities add about 3-10 times more Cd to the atmosphere than from natural resources such as forest fire and volcanic emissions. As a matter of fact, some studies have shown that NiCd batteries contribute almost 80% of cadmium to the environment,4,23 while the atmosphere is contaminated when cadmium is smelted and released as vapor into the atmosphere4 Consequently, terrestrial, aquatic, and atmospheric environments become contaminated with cadmium and remain reservoirs for human cadmium poisoning. 

Nriagu J O. Global inventory of natural and anthropogenic emissions of trace metals to the atmosphere. Nature 1979 279 409M11. 

The value of technophility indices testifies to a higher actual and potential danger of such metals as Pb, Hg, and Cd in comparison with, let s say, Mn or Fe. These are also supported by registered changes in the global emissions of heavy metals into the atmosphere and oceans (Table 3). 

Besides its low natural concentrations, Hg is mostly anthropogenically introduced into the environment. The anthropogenic sources of Hg are numerous and worldwide. The annual emissions are estimated to be between 2700 and 6000 tons. The global cycle of Hg involves the emission of the metal from land and water surfaces into the atmosphere, its transport in the atmosphere on a global scale, possible conversion to unidentified soluble species, and return to land and water by various depositional processes [4]. In the aquatic system numerous transformations take place, which are mainly microbiological processes. An overview of the most common Hg species in the environment is given in Figure 22.1. 

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