Invasion of the abyssal North Atlantic by modern anthropogenic lead

Abstract

While anthropogenic emissions have dramatically elevated lead concentrations in the North Atlantic troposphere and surface waters by orders of magnitude above natural levels [Murozumi et al., 1969; Schaule and Patterson, 1983; Boyle et al., 1986], it has been assumed that the relatively low lead levels in North Atlantic abyssal waters are not yet contaminated [Schaule and Patterson, 1981; Flegal and Patterson, 1983]. That misperception is redressed by the following stable lead isotopic composition data which reveal the advective transport of industrial lead into those deep basin waters through the formation of North Atlantic Deep Water (NADW). Additionally, spatial gradients in the isotopic signatures of anthropogenic lead within the North Atlantic abyss appear to serve as transient tracers of contaminant penetration rates.