Classification of Water Constituents

Natural organic matter (NOM) is derived from plant or microbial residues, or it is produced in situ in water by life cycles and by a variety of decomposition pathways. Humic material (HM) is found in surface water. Its concentration is typically about 50% of the DOM. HM itself consists of the fulvic acid (FA) fraction that is soluble in water of all pH values and has an average molar mass M of 500-2000 g moh. In contrast, the humic acid (HA) fraction is only soluble under acidic conditions. HA has an average molar mass M of 2000-5000 g mol and higher (Sigg and Stumm, 1996). The composition and structure of HM or of hu- 

However, modern analytical techniques, for example capillary gas-chromatogra-phy coupled with mass-selective detectors (GC-MS) allow the characterization of 

The complexity of water chemistry and the diversity of its constituents results in a system of water quahty criteria that is based on the relationship between pollutant concentrations and environmental and human health effects. The compilation of the Environmental Protection Agency currently covers 157 priority pollutants (EPA, 1999). It lists estimations of maximum and continuous concentrations of pollutants in surface water according to the latest scientific information. Accordingly, the analytical-chemical requirements of water analyses and the correct assessments of their results are enormous (cf Kolle, 2001). 

The most important analytical parameters for the description of water quality and some randomly selected examples are presented in Tab. 5-1. These parameters are usually subdivided into global, group and specific parameters and into bacteriological and toxicological qualities. Global parameters (or sum parameters) of water quality are not substrate specific. Group parameters are related to defined classes of compounds such as chlorinated hydrocarbons, PAHs, phenols, whereas specific parameters indicate the concentrations of single chemicals present in 

Total Dissolved Gases Global Parameters Group Parameters Specific Parameters Other Element-ZSubstance Specific Data 

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