Human impacts have caused dramatic changes in
the geochemical cycle of many elements, and the
possible effects of these changes have raised increasing
concern on a regional and global scale (Fyfe
1981; Buat-Ménard 1993). Based on the most recent
inventories of natural and anthropogenic source
terms (Nriagu and Pacyna 1988; Nriagu 1989; Pacyna
et al. 1995; Olendrzynski et al. 1996), total anthropogenic
lead emissions to the atmosphere make
up 332!109 g/year(range: 288.7–376), compared to
estimated total natural emissions of 12!109 g/year
(range: 0.9–23.5). Table 1 lists the estimated contributions
of various natural and anthropogenic
sources in more detail.
Of all the pollutant metals, lead yields the highest
interference factor (IF; Nriagu 1978), which is calculated
as: