Endocrine Disruption of Water and Sediment Extracts in a Non-Radioactive Dot Blot/RNAse Protection-Assay Using Isolated Hepatocytes of Rainbow Trout (14 pp).Deficiencies between bioanalytical effectiveness and chemically determined concentrations and how to explain them

Abstract

Overall, only a minor portion of the endocrine activity detected by bioassays could be linked to compounds identified by chemical analysis. In vitro assays for assessment of endocrine activities are useful as sensitive integrating methods that provide quantitative estimates of the total activity of particular receptor-mediated responses. Although discrepancies may also result from different bioanalytical approaches, it is overall likely that bioanalytical and not chemical analytical approaches give the correct estimate of endocrine disrupting potencies in environmental samples. As a conclusion, assessment of endocrine disruption based on chemical analysis alone does not appear sufficient and further research into the spectrum of substances with potential endocrine activity as well as into additive or even synergistic effects in complex environmental samples is urgently needed.

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

“…Mass-balance estimates of all major compounds contributing to the observed effects can be calculated to elucidate if all of the activity has been identified, and to assess the potential for interactions such as synergism or antagonism among contaminants present in the complex mixtures (Hilscherova et al 2000;Korner et al 2000). This strategy has been widely used for dioxin-like compounds (Safe 1990; Van den Berg et al 1998), and has recently been adopted for estrogenic chemicals (Hilscherova et al 2000;Hollert et al 2005;Khim et al 1999c;Korner et al 2000). Finally, a confirmation step in the EDA procedure evaluates how much of the observed toxicity in the environmental sample can be attributed to the mixture of identified toxicants (Brack 2003).…”

“…By means of bioassay-directed fractionation using estrogen-sensitive systems such as MVLN or MCF7-luc cells, it could be demonstrated that the concentrations of the endogenous estrogen 17β-estradiol and the synthetic estrogen ethinylestradiol represented between 88% and 99.5% of the total estrogen equivalents in water samples from certain areas (Snyder et al 2001). However, other studies revealed that synthetic chemicals such as alkylphenolic compounds can account for the majority of the estrogenic potential of a sample (Hollert et al 2005;Khim et al 1999b;Routledge et al 1998;Sheahan et al 2002). One of the key challenges for the assessment of the contribution of individual chemicals to the bioassay derived estrogenic potential (estradiol equivalents=EEQs) of a sample is the sensitivity of the utilized analytical method, as has been demonstrated by a study assessing estrogenic compounds in complex environmental samples in the catchment area of the River Neckar, Germany (Hollert et al 2005).…”

“…However, other studies revealed that synthetic chemicals such as alkylphenolic compounds can account for the majority of the estrogenic potential of a sample (Hollert et al 2005;Khim et al 1999b;Routledge et al 1998;Sheahan et al 2002). One of the key challenges for the assessment of the contribution of individual chemicals to the bioassay derived estrogenic potential (estradiol equivalents=EEQs) of a sample is the sensitivity of the utilized analytical method, as has been demonstrated by a study assessing estrogenic compounds in complex environmental samples in the catchment area of the River Neckar, Germany (Hollert et al 2005). Those estrogenic chemicals that were detected at concentrations above the method detection limits, including nonyl-and octylphenol, phthalates, PCBs, bisphenol A, and DDT, were only able to explain 9% to 14% of the total Bio-EEQs.…”

Endocrine disruptor screening: regulatory perspectives and needs

“…For example, Kidd et al [7] demonstrated declines in populations of certain fish species after exposure to environmentally relevant concentrations of the synthetic estrogen ethinylestradiol in whole lake experiments. Additionally, various studies demonstrated the potential of sediment-bound EDCs to cause adverse effects in aquatic wildlife using different in vitro and in vivo assays [26,27,29,30,[37][38][39]. Recent studies predicted that the objective of the WFD to achieve good ecological/chemical status by 2015 is likely to fail in many European catchment areas because of the continuing remobilization of sedimentbound pollutants in heavily contaminated old sediments [40][41][42].…”

“…A number of studies have been conducted to characterize the endocrine potential of municipal effluents [24,25], surface water [26][27][28] and sediments [26,27,29,30], and there has been increasing awareness of the need for testing approaches targeting EDCs to be included into current environmental assessments and monitoring [31][32][33][34][35][36] …”