A survey of 17α-ethinylestradiol and mestranol residues in Hawkesbury River, Australia, using a highly specific enzyme-linked immunosorbent assay (ELISA) demonstrates the levels of potential biological significance

Exposure to an environmentally relevant concentration of 17α-ethinylestradiol disrupts craniofacial development of juvenile zebrafish

Endocrine disrupting chemicals (EDCs) can interact with native hormone receptors to interfere with and disrupt hormone signalling that is necessary for a broad range of developmental pathways. EDCs are pervasive in our environment, in particular in our waterways, making aquatic wildlife especially vulnerable to their effects. Many of these EDCs are able to bind to and activate oestrogen receptors, causing aberrant oestrogen signalling. Craniofacial development is an oestrogen-sensitive process, with oestrogen receptors expressed in chondrocytes during critical periods of development. Previous studies have demonstrated a negative effect of high concentrations of oestrogen on early craniofacial patterning in the aquatic model organism, the zebrafish (Danio rerio). In order to determine the impacts of exposure to an oestrogenic EDC, we exposed zebrafish larvae and juveniles to either a high concentration to replicate previous studies, or a low, environmentally relevant concentration of the oestrogenic contaminant, 17α-ethinylestradiol. The prolonged / chronic exposure regimen was used to replicate that seen by many animals in natural waterways. We observed changes to craniofacial morphology in all treatments, and most strikingly in the larvae-juveniles exposed to a low concentration of EE2. In the present study, we have demonstrated that the developmental stage at which exposure occurs can greatly impact phenotypic outcomes, and these results allow us to understand the widespread impact of oestrogenic endocrine disruptors. Given the conservation of key craniofacial development pathways across vertebrates, our model can further be applied in defining the risks of EDCs on mammalian organisms.

Effect-directed analysis of a hospital effluent sample using A-YES for the identification of endocrine disrupting compounds

An effect-directed analysis (EDA) approach was used to identify the compounds responsible for endocrine disruption in a hospital effluent (Basque Country). In order to facilitate the identification of the potentially toxic substances, a sample was collected using an automated onsite large volume solid phase extraction (LV-SPE) system. Then, it was fractionated with a two-step orthogonal chromatographic separation and tested for estrogenic effects with a recombinant yeast (A-YES) in-vitro bioassay. The fractionation method was optimized and validated for 184 compounds, and its application to the hospital effluent sample allowed reducing the number of unknowns from 292 in the raw sample to 35 after suspect analysis of the bioactive fractions. Among those, 7 of them were confirmed with chemical standards. In addition, target analysis of the raw sample confirmed the presence of mestranol, estrone and dodemorph in the fractions showing estrogenic activity. Predictive estrogenic activity modelling using quantitative structure-activity relationships indicated that the hormones mestranol (5840 ng/L) and estrone (128 ng/L), the plasticiser bisphenol A (9219 ng/L) and the preservative butylparaben (1224 ng/L) were the main contributors of the potential toxicity. Derived bioanalytical equivalents (BEQs) pointed mestranol and estrone as the main contributors (56 % and 43 %, respectively) of the 50 % of the sample's explained total estrogenic activity.

17α-Ethinylestradiol (EE2): concentrations in the environment and methods for wastewater treatment – an update

17α-Ethinylestradiol (EE2) is a frequently used drug and an endocrine disruptive substance. Adverse effects on biota have been reported when they are exposed to this substance in the environment. The last review on EE2 in the environment was published in 2014. Since then, well above 70 studies on EE2 and related substances have been published. The aim of this review was therefore to bring together recent data with earlier ones. The topics emphasized were observable trends of environmental levels of EE2 and methods to reduce EE2 levels in wastewater, before it can enter the environment. This should give an overview of the recent knowledge and developments regarding these environmental aspects of EE2. In the studies discussed, EE2 levels in surface waters were well detectable in many countries, both above and below the predicted no effect concentration (PNEC) of 0.035 ng L⁻¹, although analytical methods used for the quantification often are unsatisfactory regarding their limit of detection. To support the degradation of EE2 prior to entry into the environment, appropriate treatment methods could help to control the emissions of EE2. Several methods for the reduction of EE2 levels of up to 100% removal efficiency were reported recently and are of chemical, biological, adsorptive or ion-exchange nature. Depending on the required properties like initial EE2 concentration or treatment duration, several promising methods are available.

17α-Ethinylestradiol (EE2) is a frequently used drug and an endocrine disruptive substance.

Development of a portable electroanalytical method using nickel modified screen-printed carbon electrode for ethinylestradiol determination in organic fertilizers

Urine and struvite are organic fertilizers that have all nutritional requirements for the growth of a plant. However, these fertilizers may contain some emerging organic contaminants, such as ethinylestradiol, which is one of the most common hormones found in aquatic environments and can cause several changes in living organisms. Thus, the present study developed a fast, sensitive, inexpensive, and portable method for determining ethinylestradiol in urine and struvite, using square wave voltammetry (SWV) and screen-printed carbon electrodes modified with electrodeposited nickel film (SPCE-Ni). The electrodeposition of the nickel film on the screen-printed electrode was performed by cyclic voltammetry and optimized using complete factorial design 2³ and central composite design. The parameters optimized for SPCE-Ni were: number of cycles (1000); scan rate (5 V s^-1) and Ni²⁺ concentration (9.4 mmol L^-1). The operational parameters of the SWV for ethinylestradiol analysis were also optimized by experimental designs and obtained the following optimal values: step potential (10 mV), modulation amplitude (40 mV), and frequency (20 Hz). The method used 0.1 mol L^-1 BR buffer (pH 8.0) as support electrolyte and presented a limit of detection of 0.052 µmol L^-1 (R² = 0.996). Ethinylestradiol recovery test in struvite, human urine, synthetic urine, and pharmaceutical tablets ranged from 93.9% to 107.5%, indicating that there is no matrix effect. Furthermore, an interference test was performed with several drugs did not show any significant changes in the ethinylestradiol analytical signal, guaranteeing a greater precision of the method. These results reinforce the possibility of applying the proposed method in loco with a practical and fast way, without the need to use significant amounts of sample.

Monitoring pharmaceuticals in the aquatic environment using enzyme-linked immunosorbent assay (ELISA)-a practical overview

The presence of pharmaceuticals, which are considered as contaminants of emerging concern, in natural waters is currently recognized as a widespread problem. Monitoring these contaminants in the environment has been an important field of research since their presence can affect the ecosystems even at very low levels. Several analytical techniques have been developed to detect and quantify trace concentrations of these contaminants in the aquatic environment, namely high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, usually coupled to different types of detectors, which need to be complemented with time-consuming and costly sample cleaning and pre-concentration procedures. Generally, the enzyme-linked immunosorbent assay (ELISA), as other immunoassay methodologies, is mostly used in biological samples (most frequently urine and blood). However, during the last years, the number of studies referring the use of ELISA for the analysis of pharmaceuticals in complex environmental samples has been growing. Therefore, this work aims to present an overview of the application of ELISA for screening and quantification of pharmaceuticals in the aquatic environment, namely in water samples and biological tissues. The experimental procedures together with the main advantages and limitations of the assay are addressed, as well as new incomes related with the application of molecular imprinted polymers to mimic antibodies in similar, but alternative, approaches. Graphical Abstract.

17β-Estradiol residues and estrogenic activities in the Hawkesbury River, Australia

Two highly sensitive ELISAs for the specific detection of 17β-estradiol (E2) residues were developed, showing the limits of detection (LOD, a concentration at 15% inhibition of color development) of 0.04 ± 0.02 μg/L and 0.05 ± 0.03 μg/L. The average recovery rate of the river water samples spiked with E2 at 1-50 ng/L range was 111.5% (68.6-252%) with the % relative standard deviation (RSD) of 0.5-86.3%. The ELISA demonstrated a good correlation with the GC-MS analyses of the spiked river water samples (r = 0.909). Applying the developed E2 ELISA assay to the monitoring of E2 residues in Hawkesbury River (New South Wales, Australia) found that all the tested creek samples contained E2 residues less than the biologically significant level of 10 ng/L. However, 25% of the water samples tested demonstrated the estrogen activity (determined by the yeast estrogen screening (YES) assay) above the levels that have been linked to the adverse effects in fish and other aquatic organisms (> 20 E2 Eq ng/L). It was apparent that the E2 residues together with the EE2 residues (reported in our previous study) contributed to most of the observed estrogenic activity in Hawkesbury River.