Method for EDTA speciation determination: application to sewage treatment plant effluents

This paper presents an HPLC method allowing the quantification of EDTA speciation, specifically the Fe(III)EDTA species, which is the only one considered to undergo significant degradation in the environment via photoreduction. The method relies on the exchange kinetics of metals with EDTA. Preliminary results were obtained by applying the method to the study of sewage treatment plants. We measured the evolution of the total EDTA concentration during the sewage treatment, together with the changes of EDTA speciation following the process. Special attention is given to the quantitative importance of the Fe(III)EDTA species.