Abstract
The aminopolycarboxylic acids ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) have attracted considerable industrial and commercial attention due to their effectiveness in metal masking and prevention of precipitation. EDTA and NTA are variously used in households and industries, wherever metal ions have to be kept in solution by complexation. Due to the wide field of their application and their high polarity, these substances reach the aquatic environment at considerable concentrations (in the µg/L-range) and have also been detected in drinking water. Recently, alternative aminopolycarboxylic acids such as diethylenetriaminepentaacetic acid (DTPA), ß-alaninediacetic acid (ß-ADA), 1,3-propylenediaminetetraacetic acid (1,3-PDTA), and methylglycinediacetic acid (MGDA) play a certain part. Even though EDTA and NTA have received exceptional attention in the literature in the past, there is no detailed review covering the knowlege of all aminopolycarboxylic acids mentioned above. This gap will now be closed by an extensive literature survey carried out by the TZW. This review will cover several aspects of aminopolycarboxylates, such as physico-chemical properties, production processes, production volumes, application areas, development of substitutes, analysis, entry and occurrence in waters, elimination by conventional and advanced sewage purification processes, behaviour during drinking water treatment, classical toxicology and ecotoxicology (incl. eutrophication, biotic and abiotic elimination, influence on the distribution of heavy metals between sediment and water, and aquatic toxicology). Finally, the potential risk of this group of substances will be assessed. Thereby, emphasis will also be put on the relevant aminopolycarboxylate speciation (i.e. the identity of the complexed metal ion), a subject which has often not been considered in more detail in previous overviews.

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