Recent variations in heavy metal concentrations in firn and air from the Antarctic Peninsula
A snow-pit and hand-drilled core have been sampled at Spaatz Island in the Antarctic Peninsula to obtain evidence on the importance of short-term fluctuations of heavy metal (Cd, Cu, Pb, and Zn) concentrations. A programme of air sampling was undertaken at the same time to investigate directly the link between concentrations in air and in snow. The snow samples and air filters have been analysed by atomic absorption spectrometry (AAS) following preconcentration on tungsten wires and by differential pulse anodic stripping voltammetry (DPASV). One sequence of snow samples was preconcentrated in the field and analysed later for Cd in the laboratory.
The snow analyses confirm that year-to-year variations in heavy metal concentrations may be comparable with changes due to long-term variations in global emission rates to the atmosphere from industrial sources. The importance of understanding these apparently meteorologically controlled processes is underlined. Averaged data from the combined air/snow sampling programme show a satisfactory linear relationship between concentrations in air and in snow for both the heavy metals and for the cation component of the marine aerosol. The results, considered in the light of Junge's model for static rainout, give a ratio for concentration in air (ng m−3)/concentration in snow (ng g−1) of 0.6±0.3.