Effects-directed analysis (EDA) and toxicity identification evaluation (TIE): Complementary but different approaches for diagnosing causes of environmental toxicity

Abstract

Currently, 2 approaches are available for performing environmental diagnostics on samples like municipal and industrial effluents, interstitial waters, and whole sediments to identify anthropogenic contaminants causing toxicological effects. One approach is toxicity identification evaluation (TIE), which was developed primarily in North America to determine active toxicants to whole-organism endpoints. The second approach is effects-directed analysis (EDA), which has origins in both Europe and North America. Unlike TIE, EDA uses primarily in vitro endpoints with an emphasis on organic contaminants as the cause of observed toxicity. The 2 approaches have fundamental differences that make them distinct techniques. In EDA, the sophisticated and elegant fractionation and chemical analyses performed to identify the causes of toxicity with a high degree of specificity often compromise contaminant bioavailability. In contrast, in TIE, toxicant bioavailability is maintained and is considered critical to accurately identifying the causes of environmental toxicity. However, maintaining contaminant bioavailability comes with the cost of limiting, at least until recently, the use of the types of sophisticated fractionation and elegant chemical analyses that have resulted in the high specificity of toxicant diagnosis performed in EDA. The present study provides an overview of each approach and highlights areas where the 2 approaches can complement one another and lead to the improvement of both.

The European technical report on aquatic effect-based monitoring tools under the water framework directive

“…Both approaches combine biotesting, physicochemical fractionation and chemical analysis in a sequential procedure. However, the philosophy behind both approaches is slightly different [21]. The TIE approach has its origin in whole effluent testing, which focuses on the question, whether an effluent will cause adverse effects on aquatic organisms when emitted to the environment.…”

The value of zebrafish as an integrative model in effect-directed analysis - a review

“…Target and non-target chemical analyses are applied to select candidates and identify bioactive substances. Bioassays again play an important role in the confirmation phase, for biotesting of the pure substance identified as the bioactive compound [3][4][5].…”

“…For accurate identification of bioactive fractions, the bioassays should present high sensitivity and low internal test variability and be able to detect different chemicals that address similar endpoints or modes of action. Furthermore, due to limited sample amounts and large numbers of fractions to be tested, high-throughput low-volume bioassays are required [5].…”

Toxicology of Marine Mammals: New Developments and Opportunities

“…Apart from these studies, an additional step forward in in vitro studies has been the development of biosensor systems, which use engineered cells (i.e. bioassays) to be applied to marine mammals and concepts like 'effect-driven approach' (EDA), 'adverse outcome pathway' (AOP) and 'toxicity pathway' (Yordy et al 2010;Burgess et al 2013;Jin et al 2013Jin et al , 2015Simon et al 2013). These developments allow to screen marine mammal tissue samples with respect to specific endpoints and, depending on the study design, can be used as an initial step to explore the influence of contaminant mixtures.…”