Analytical Chemistry in High-Alpine Environmental Research

Snow and ice chemistry studies in the high-altitude regions of the Alps give insight into present and past atmospheric chemistry. Impurities found in snow originate from atmospheric aerosol particles or reactive trace gases and, thus, represent a broad spectrum of chemical species such as water-soluble inorganic and organic ions, insoluble minerals, organic components, soot, trace metals, etc. Consequently, a variety of analytical techniques need to be applied in snow chemistry studies, including ion chromatography, inductively coupled plasma optical emission or mass spectrometry, atomic absorption spectrometry etc. A few details of the respective methods used in our laboratory are discussed here. Since snow samples are characterised by low impurity concentrations, they are particularly sensitive with respect to stability and contamination. Thus, special care in sample handling is required. Investigations of the geographical, seasonal and year-to-year variations of the concentrations and deposition fluxes of major ionic species were carried out in the Alps. Concentrations of ammonium, nitrate and sulphate showed a West to East increase, which was, however, not reflected in the total flux, since precipitation heights exhibited an opposite pattern. Long-term records from an alpine glacier revealed substantial increases of sulphate, ammonium, nitrate, and lead in the course of the last 100 years.