Analytical methods for the direct determination of inorganic and organic species: seasonal changes of iron, sulfur, and pedogenic and aquogenic organic constituents in the eutrophic Lake Bret, Switzerland

Because the behaviour of elements and organic compounds in the environment depended on the properties of the chemical form in which they occurred, the need for analytical methods which provided data on the nature, concentrations and properties of the different chemical forms, not just total concentrations present, is discussed. These data are needed for an understanding of environmental cycles. Available methods discussed include differential pulse polarography, colorimetry, flame atomic absorption spectrometry, absorbance measurements, fluorescence measurements, cathodic sweep voltammetry, filtration, and calculations based on formation, equilibrium, and solubility product constants. These methods were used to identify iron and sulphur species and natural organic matter in the waters of Bret lake, Switzerland. A bibliography of 38 references is appended.