Runoff and total corrosion loss for copper and zinc were investigated at seven sites in Switzerland. The exposure sites were chosen near the stations of the National Air Pollution Monitoring Network (NABEL), where climatic and air pollution data are measured. Runoff and corrosion rates were investigated after 0.5, 1, 2 and 4 years of exposure. Runoff rates differ from corrosion rates depending on the material, the exposure time and the sampling site.

No abstract

This study explored the possibility of using laser ablation inductively-coupled plasma-mass spectroscopy to measure trace metals and other elements within the annual growth layers of the teeth of walrus harvested from the Canadian Arctic. Using sample ablation "footprints" of 125 microns diameter on transects across the exposed cross-sections of teeth, this technique detected Pb, Cu, Zn and Sr, but not Cd, in tooth cementum. The micro-spatial patterns of elements were consistent among different transects on the same tooth, and revealed subtle differences between animals of different ages. The youngest walrus in the sample (4 yr) contained higher concentrations of Pb and Cu than older animals in the growth layer deposited during the first year of life, while the oldest animal (33 yr) exhibited higher Pb and Zn than younger animals in the outer layer corresponding to the year 1988. The differences between animals and across annual layers may reflect both life history and metal exposure phenomena, including high amounts of metals transferred from mothers to pups in maternal milk. The ability to detect metals in a repeatable fashion within annual growth layers suggests that metal exposure histories accurate to within a year might be re-constructed for the life-times of long-lived animals, and that a series of such individual studies would allow exposure histories covering centuries to be quickly assembled. These data may suggest the most likely explanation for the currently high levels of some metals observed in certain Arctic marine mammals, i.e., natural phenomenon or anthropogenic contamination.

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A new technique is evaluated for normalizing laser power fluctuations in laser-ablation atomic spectrometry. The technique involves measuring the light loss caused by scattering from the ablated material as it flows through a specially designed cell. The resulting measured optical density can be used to correct for variations in the amount of sample that has been ablated. This new approach is compared to the use of a matrix element as an internal standard. Three different excitation sources for AES (Ar-ICP, Ar-MIP, and He-MIP) were combined with laser ablation and evaluated with the new normalization approach. Although the overall performance is best for the Ar-ICP combination, the MIPs have some desirable characteristics (i.e., low background radiation) which in some cases lead to better results. The spectra were collected with a photodiode-based spectrometer that is designed for simultaneous multichannel detection and is therefore especially well suited to measurement and background correction of signals produced during transient sampling such as with laser ablation. The ability of such a spectrometer to deal with complex samples such as cast iron is discussed.