Global Mass Balance of Lead

Dobrovolsky has conducted a detailed consideration of global lead mass balance in 1994. The pools and fluxes of this heavy metal are shown in Table 30 and 31. 

We can compare the natural and anthropogenic emissions of lead in the global cycle. Table 32 shows the natural sources and Table 33 demonstrates the major anthropogenic ones. 

Data of other researchers differ appreciably from the data of Table 32. For example, Thornton et al (1995) considered the integral natural emission of lead as much as 35 X 10 tons/year. According to data of Geological Survey of Canada (GSC, 1995), the natural inflow of lead to atmosphere can reach 330 x 10- tons/year. 

As evident from Table 33, the uncertainty level of the estimates is significant. The mid-1990s estimates are given by Thornton etal (1995) and the global anthropogenic emission was calculated as much as 450 x 10- tons per year. The latest estimates were made for various continents by Pacina et al, 1998 (Table 34) 

We can see that anthropogenic emissions of lead are most important in developed industrial countries because they are mainly associated with fossil fuel combustion for power generation and with transport. The highest emission per individual is in Australia due to non-ferrous industry emissions predominating on this continent. As to the pollution density per area unit, however, Europe is ahead of Australia, Africa and South America by an order of magnitude. The total global emission was estimated as much as 210 x 10- tons per year with averaged emission of about 40 g/capita per year. 

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