Effect-directed analysis (EDA) in aquatic ecotoxicology: state of the art and future challenges

1 Background, aim, and scope One of the key challenges environmental toxicologists and risk assessors are facingisthe characterization and assessment of the complex exposure scenarios that are typical for many environments we wish to protect. During the early days of ecotoxicology, it became obvious that the sole use of classic chemical–analytical techniques is not suitable of addressing this issue. Specifically, analysis of the vast number of chemicalstypically present inanenvironmental samplewould not only beprohibitivelyexpensive but simplyimpossibledue to limits in the available analytical methodologies for many chemicals—especially as often no a priori knowledge of the chemicals exists which are present in the sample. Therefore, approaches have been developed supplementing chemical analysis with bio-analytical techniques that make use of the specific properties of specific groups of chemicals to interfere with specific biological processes. This type of analysis has been coined effect-directed analysis (EDA) and is based on a combination of fractionation procedures, bio-testing, and subsequent chemical analyses (Brack 2003; Brack et al. 2003; Samoiloff et al. 1983; Schuetzle and Lewtas 1986).