Maternal transfer of emerging brominated and chlorinated flame retardants in European eels

The European eel (Anguilla anguilla) is regarded as a critically endangered species. Scientists are in agreement that the “quality of spawners” is a vital factor for the survival of the species. This quality can be impaired by parasites, disease and pollution. Especially endocrine  disrupting organic chemicals pose a potential threat to reproduction and development of offspring.  To our knowledge, the findings in this publication for the first time describe maternal transfer of contaminants in eels. We analysed the concentrations of in total 53 polybrominated diphenyl ethers (PBDEs) and their halogenated substitutes in muscle, gonads and eggs of  artificially matured European eels and in muscle and gonads of untreated European eels that were used for comparison. We found evidence that persistent organic pollutants such as PBDEs, as well as their brominated and chlorinated substitutes are redistributed from muscle tissue to gonads and eggs. Concentrations ranged from 0.001 ng g-1 ww for sum Dechlorane metabolites (DPMA, aCL10DP, aCl11DP) to 2.1 ng g-1 ww for TBA in eggs, 0.001 ng g-1 ww for Dechlorane metabolites to 9.4 ng g-1 ww for TBA in gonads and 0.002 ng g-1 ww for Dechlorane metabolites to 54 ng g-1 ww for TBA in muscle tissue. Average egg muscle ratios (EMRs) for  compounds detectable in artificially matured eels from both Schlei Fjord and Ems River ranged from 0.01 for Dechlorane 602  (DDC-DBF) to 10.4 for PBEB. Strong correlations were found between flame retardant concentrations and lipid content in the analysed tissue types, as well as transfer rates and octanol-water partitioning coefficient, indicating that these parameters  were the driving factors for the observed maternal transfer. Furthermore, indications were found, that TBP-DBPE, TBP-AE, BATE and TBA have a significant uptake from the surrounding water, rather than just food and might additionally be formed by metabolism or biotransformation processes. Dechloranes seem to be of increasing relevance as contaminants in eels and are transferred to eggs. A change of the isomer pattern in comparison to the technical product of Dechlorane Plus (DP) was observed indicating a redistribution of DP from muscle tissue to gonads during silvering with a preference of the syn-isomer. The highly bioaccumulative DDC-DBF was the most abundant Dechlorane in all fish of the comparison group even though it is not produced or imported in the EU. The aldrin related “experimental flame retardant” dibromoaldrin (DBALD) was detected for the first time  in the environment in similar or higher concentrations than DP. </p

Non-target assessment of the maternal transfer of non-polar toxic organic compounds in European eels by GCxGC-TOF and GC-FTICR-MS

Chemical pollution is hypothesized as one of the factors driving the strong decline of the critically endangered European eel population. Specifically the impact of contaminants on the quality of spawning eels and subsequent embryo survival and development has been discussed as crucial investigation point. However, so far only very limited information on potential negative effects of contaminants on the reproduction of eels is available.  Through the combination of non-targeted ultra-high resolution mass spectrometry and multidimensional gas chromatography, combined with more conventional targeted analytical approaches, compounds of particular relevance and their maternal transfer in artificially matured European eels from the German river Ems have been identified.  Substituted diphenylamines were, unexpectedly, found to be the primary organic contaminants in the eel samples, with concentrations exceeding 10 µg g-1 ww. Furthermore, it could be shown that these contaminants, as well as known contaminants in eel such as polychlorinated biphenyls (PCBs), organochlorine pesticides and polyaromatic hydrocarbons (PAHs), are not merely stored in lipid rich tissue of eels, but maternally transferred into gonads and eggs.  The results of this study provide unpreceded information on both the fate and behavior of substituted diphenylamines in the environment as well as their relevance as contaminants in European eels.</p

Evidence for High Concentrations and Maternal Transfer of Substituted Diphenylamines in European Eels Analyzed by Two-Dimensional Gas Chromatography–Time-of-Flight Mass Spectrometry and Gas Chromatography–Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Chemical pollution is hypothesized to be one of the factors driving the strong decline of the critically endangered European eel population. Specifically, the impact of contaminants on the quality of spawning eels and subsequent embryo survival and development has been discussed as crucial investigation point. However, so far, only very limited information on potential negative effects of contaminants on the reproduction of eels is available. Through the combination of nontargeted ultrahigh-resolution mass spectrometry and multidimensional gas chromatography, combined with more-conventional targeted analytical approaches and multimedia mass-balance modeling, compounds of particular relevance, and their maternal transfer in artificially matured European eels from the German river Ems have been identified. Substituted diphenylamines were, unexpectedly, found to be the primary organic contaminants in the eel samples, with concentrations in the μg g^–1 wet weight range. Furthermore, it could be shown that these contaminants, as well as polychlorinated biphenyls (PCBs), organochlorine pesticides, and polyaromatic hydrocarbons (PAHs), are not merely stored in lipid rich tissue of eels but maternally transferred into gonads and eggs. The results of this study provide unique information on both the fate and behavior of substituted diphenylamines in the environment as well as their relevance as contaminants in European eels