Antarctic snow record of cadmium, copper, and zinc content during the twentieth century

A snowpit in Coats Land, Antarctica, has been sampled in order to obtain a record of Cd, Cu and Zn covering the period 1923-1986. The snowpit record g ives an indication of southern hemisphere (SH) pollution reaching Antarctic a. For Zn, concentrations (averaging 1.5 ng kg(-1)) can be explained as ari sing from natural crustal dust (based on Zn/Al ratios). No increase is obse rved over the period of the record here, despite a large increase in emissi ons from smelting operations. The main emitters are near the equator, and t his may explain the lack of response in the Antarctic record. For Cd, conce ntrations (averaging 0.1 ng kg(-1)) cannot easily be explained in terms of natural emissions, unless the volcanic input is dominant. No significant in crease is seen in the snow for this metal also. For Cu, the natural input c an explain only a small part of the concentration (averaging 3.5 ng kg(-1)) measured, and increased concentrations (factor 2) are seen in the 1970s an d 1980s compared to earlier decades. This is consistent with increased emis sions from Cu smelting activities, particularly in Chile, where emissions a re relatively far south compared to the main part of SH landmasses. Cu thus joins Pb as a metal whose natural cycle has been significantly perturbed e ven in the Antarctic atmosphere. (C) 1999 Elsevier Science Ltd. All rights reserved.