Occurrence and environmental risk assessment of 4 estrogenic compounds in surface water in Belgium in the frame of the EU Watch List.

The presence of natural estrogens estrone (E1), 17ß-estradiol (E2), estriol (E3) and synthetic estrogen 17α-ethynylestradiol (EE2) in the aquatic environment has raised concerns because of their high potency as endocrine disrupting chemicals. The European Commission (EC) established a Watch List of contaminants of emerging concerns including E1, E2 and EE2. The proposed environmental quality standards (EQSs) are 3.6, 0.4, 0.035 ng/L, for E1, E2, EE2, respectively. A thorough evaluation of analytical procedures developed by several studies aiming to perform sampling campaigns in different European countries highlighted that the required limits of quantification in surface water were not reached, especially for EE2 and to a lesser extent for E2. Moreover, data regarding the occurrence of these contaminants in Belgian surface water are very limited. A sampling campaign was therefore performed on a wide range of rivers in Belgium (accounting for a total of 63 samples). The detection frequencies of E1, E2, E3 and EE2 were 100, 98, 86 and 48%, respectively. E1 showed the highest mean concentration (= 4.433 ng/L). In contrast, the mean concentration of EE2 was 0.042 ng/L. The risk quotients (RQs) were calculated based on the respective EQS of each analyte. The frequency of exceedance of the EQS was 31.7% for E1, EE2, while it increased to 44.4% for E2. The extent of exceedance of the EQS, represented by the 95th percentile of the RQ dataset, was higher than 1 for E1, E2, EE2. The use of a confusion matrix was investigated to try to predict the risk posed by E2, EE2, based on the concentration of E1.

Development And Validation Of A Method For Determining Estrogenic Compounds In Surface Water At The Ultra-Trace Level Required By The EU Water Framework Directive Watch List.

Natural estrogens (estrone: E1, 17ß-estradiol: E2, estriol: E3) and the synthetic estrogen (17α-ethinylestradiol: EE2) are endocrine disruptors harmful to aquatic wildlife. The European Commission included these molecules in the surface water Watch Lists issued in 2015 and 2018 under the Water Framework Directive regarding emerging aquatic pollutants, proposing maximum detection limits (LOD) of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. Attaining these limits represents a challenge even with the most up-to-date analytical tools, in particular in surface water. A two-step sample preparation, involving a preliminary extraction of a whole water sample on a solid-phase extraction (SPE) disk and further purification on a Florisil SPE cartridge, was optimized. The purified extract was derivatized subsequently and quantified by LC-MS/MS. The main goal was to maximize the recoveries to achieve the very low LODs required by the European Watch Lists. The method was fully validated in seven surface water. The LODs calculated were below the maximum acceptable limits required by the European Commission.

Trace analysis of estrogenic compounds in surface and groundwater by ultra high performance liquid chromatography-tandem mass spectrometry as pyridine-3-sulfonyl derivatives.

Natural estrogens (estrone: E1, 17ß-estradiol: E2, estriol: E3) and synthetic 17α-ethynylestradiol (EE2) are reported as strong endocrine disruptors even at extremely low concentrations. Therefore, the watch list from the European Commission regarding emerging aquatic pollutants recommended maximum detection limits of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. In this study, a UHPLC-ESI-MS/MS method allowing quantification of E1, E2, E3 and EE2 in aqueous matrices was developed. The analytes were derivatized using pyridine-3-sulfonyl chloride and a broad range of product ions were generated and their specificity was assessed by analyzing both surface and groundwater. At least two product ions for each estrogenic compound were proved to be specific and hence suitable for quantification and confirmation. In complex aqueous matrices, analyte responses were particularly affected by ion suppression. This phenomenon was reduced by optimizing the clean-up and selecting a suitable stationary phase for the chromatographic separation. The limits of quantification assessed in surface water with the optimized method ranged from 0.098 ng/L (EE2) to 2.73 ng/L (E3).

Differential Interaction of Synthetic Glycolipids with Biomimetic Plasma Membrane Lipids Correlates with the Plant Biological Response.

Natural and synthetic amphiphilic molecules including lipopeptides, lipopolysaccharides, and glycolipids are able to induce defense mechanisms in plants. In the present work, the perception of two synthetic C14 rhamnolipids, namely, Alk-RL and Ac-RL, differing only at the level of the lipid tail terminal group have been investigated using biological and biophysical approaches. We showed that Alk-RL induces a stronger early signaling response in tobacco cell suspensions than does Ac-RL. The interactions of both synthetic RLs with simplified biomimetic membranes were further analyzed using experimental and in silico approaches. Our results indicate that the interactions of Alk-RL and Ac-RL with lipids were different in terms of insertion and molecular responses and were dependent on the lipid composition of model membranes. A more favorable insertion of Alk-RL than Ac-RL into lipid membranes is observed. Alk-RL forms more stable molecular assemblies than Ac-RL with phospholipids and sterols. At the molecular level, the presence of sterols tends to increase the RLs' interaction with lipid bilayers, with a fluidizing effect on the alkyl chains. Taken together, our findings suggest that the perception of these synthetic RLs at the membrane level could be related to a lipid-driven process depending on the organization of the membrane and the orientation of the RLs within the membrane and is correlated with the induction of early signaling responses in tobacco cells.

Analysis of the diastereoisomers of alliin by HPLC.

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their biosynthesis. The precursor of these compounds, alliin (a sulfur amino-acid) has been obtained by chemical synthesis. However, this synthesis route also leads to a diastereoisomer as co-product. This work describes the development of an analytical method which allows the separation and quantification of the two diastereoisomers in order to determine in which proportion the natural form can be produced. The HPLC method which was optimized and validated by accuracy profile exploits an original stationary phase consisting of porous graphitic carbon (PGC). Furthermore, the developped method was used to separate the diastereoisomers of methiin, another cysteine sulfoxide, and to analyze an aqueous extract of garlic. The ability to quantify the amount of natural alliin is valuable for further work on garlic molecules and their application for health protection.