Global Mass Balance of Mercury

The up-to-date results can be compared with those of the late of 1970s. The review of natural sources of mercury emission has been carried out in some researches. Table 27 presents values of natural emissions obtained by J. Nriagu in 1989. 

Data of other authors differ appreciably from the estimates shown in Table 27. Eor example, Thornton et al (1995) believed that integral value of natural emissions to the atmosphere reach 180 x 10 tons/year, whereas those of Rasmussen (1994) were 350 x 10 tons/year. According to data of Geological Survey of Canada (GSC, 1995) the natural inflow of mercury to the atmosphere can exceed even KXX) x 10 tons/year. 

Natural source Mercnry emissions, 10 tons/year 

Source type Mercury emission flux, 10 ton/year 

A similar comparison can be conducted with results of environmental biogeo-chemical cycle of mercury. The most important anthropogenic emission sources of mercury are listed in Table 28. 

---