Estrogenic Activity Measurements in Water Using Diffusive Gradients in Thin-Film Coupled with an Estrogen Bioassay

Abstract

A novel type of diffusive gradients in thin-film (DGT) was combined with a chemically activated luciferase gene expression bioassay (CALUX) to measure estrogens in aquatic systems. The performance of this novel method was assessed with 17β-estradiol (E2) as the model steroid hormone, XAD 18 resin gel as the binding phase in the DGT method and VM7Luc4E2 cells (formerly BG1Luc4E2) for the Estrogen Responsive Element (ERE)-CALUX bioassay. The measured effective diffusion coefficient of E2 in agarose diffusive gel was 4.65 ± 0.37 × 10 cm s at 25 °C. The detection limit of this combined DGT/ERE-CALUX method for 1 day of sampling (0.026 ± 0.003 ng L of E2) is significantly lower than that obtained by spot sampling combined with GC-MS/MS or LC-MS/MS analysis (0.1-7.0 ng L). The method is independent of pH (5-8), ionic strength (0.001-0.5 M), and dissolved organic matter (DOM; concentrations up to 30 mg L). Field applications of this novel DGT in effluents of three sewage treatment plants in Beijing city (China) showed comparable results to conventional spot (grab) sampling. This study demonstrates that the combined DGT/ERE-CALUX approach is an effective and sensitive tool for in situ monitoring of estrogenic activity in waters and wastewaters.

In situ measurements of micronutrient dynamics in open seawater show that complex dissociation rates may limit diatom growth

“…The thickness of the hydrogel and the filter are known, but that of the diffusive boundary layer (DBL) has to be estimated. Recently we measured the DBL in a well-mixed water-effluent 65 . Since the glider is moving all the time and the surface water is well-mixed, a similar DBL of 0.02 cm was adopted.…”

Diffusive gradients in thin films: devices, materials and applications

“…Chen et al (2013Chen et al ( , 2014aChen et al ( , 2015a used XAD-18 as a DGT sorbent for the in situ sampling of multiple antibiotics in water and soil, combined with the DIFS model to investigate the supply kinetics of antibiotics from soil solid phase into solution. Estrogenic activity was measured by XAD-18 DGT and conventional grab sampling, with good agreement between conventional sampling methods and DGT sampling results (Guo et al 2017b). However, the DGT method provided the additional benefits of being in situ technique and more efficient in terms of cost, time, and labor.…”

“…However, the DGT method provided the additional benefits of being in situ technique and more efficient in terms of cost, time, and labor. Moreover, XAD-18 DGT has been employed to measure the concentration of illicit drugs in wastewater and rivers, showing no significant difference in detected concentrations between DGT and active sampling methods; although the concentrations obtained by DGT were slightly lower than with active sampling (Guo et al 2017b;Zhang et al 2018b). Xie et al (2018a) found that antibiotics concentrations in seawater were significantly different using XAD-1 DGT and active sampling.…”

Using Estrogenic Activity and Nontargeted Chemical Analysis to Identify Contaminants in Sewage Sludge

“…Careful statistics and modes of prioritization are necessary to select features of importance for further identification efforts , such as quantitative structure–activity relationships (QSARs) and in vitro bioassay measurements. QSAR is commonly used to predict activity based on structural moieties and has been used in a wide range of applications, including adsorption, distribution, metabolism, elimination, and toxicity, − but while QSAR models can be useful tools for predicting the toxicity or biological activity of individual compounds, chemicals in complex mixtures are often influenced by multiple compounds acting concurrently, which is where mechanism-based in vitro bioassays can help identify endocrine-active chemical mixtures …”