engleski

Surfactant-Derived Alkylphenolic Compounds

The ever-expanding utilization of synthetic organic materials in the last sixty years is accompanied by an increasing flux of xenobiotic chemicals to the environment. Synthetic surfactants belong to the most important large-volume anthropogenic compounds and were among the first chemicals which revealed that unrestricted use of these promising novel materials in the human society could lead to serious environmental consequences. The introduction of widely accepted legal demand on 80 % biodegradability in the 1960s contributed to the significant decrease of surfactant concentrations in ambient waters. However, lack of analytical methods for an accurate and comprehensive assessment of the environmental fate and effects of these chemicals before the 1980s resulted in the failure to predict problems arising from the formation of toxic and/or persistent metabolites. One of the most prominent examples of possible detrimental consequences of ill-designed industrial chemicals is definitely the “ Nonylphenol story” , which was conceived in Eawag by combining the ultimate advances in capillary gas chromatography/mass spectrometry and high-performance liquid chromatography and a lucid detective work by Giger and co-workers. These studies were among the first ones to demonstrate both the necessity and feasibility of mass balance studies of highly complex mixtures of xenobiotic chemicals, including both parent compounds and all major metabolites, in wastewater treatment and ambient waters. Numerous studies around the globe confirmed the early Eawag findings, indicating ubiquitous occurrence of surfactant-derived alkylphenolic compounds, while the discovery of their endocrine-disrupting effects in fish gave a strong impulse to further studies, aimed at their comprehensive ecotoxicological assessment. Continuing development of analytical techniques, especially the recent developments of LC-MS-MS techniques gave a boost to the analysis of polar environmental contaminants. For the “ Nonylphenol story” , this meant that a number of new metabolites, including doubly oxidized carboxylated alkylphenoxy acetic acids, could be identified and analyzed in the environment. With these new data, hydrological fate models describing the fate of alkylphenolic compounds were further refined. Another recent development is the realization that the different components of the complex industrial nonylphenol mixture do not necessarily show the same environmental behaviour. Different nonylphenol isomers show different endocrine disrupting potential. In addition, laboratory tests show that biodegradation rates of different isomers vary. We will present the most important issues and turning points in the analytical chemistry and ecotoxicology of surfactant-derived alkylphenolic compounds, with a particular emphasis on the work done at Eawag and on the latest developments in the field.

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