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Partition of endocrine-disrupting chemicals between colloids and dissolved phase as determind by cross-flow ultrafiltration
journal contributionposted on 2023-06-08, 06:40 authored by Ruixia Liu, Andrew Wilding, Andrew Hibberd, John L Zhou
Cross flow ultrafiltration (CFUF) was developed first for the isolation of natural colloids, and subsequently for determining the partition of selected endocrine disrupting chemicals (EDCs) between river colloids and dissolved phase. In this study, a 1-kDa Millipore Pellicon 2 cartridge type CFUF system was validated using a range of molecular probes spiked in natural waters. Results show that good retention (>80%) of high molecular weight (HMW, > 1-kDa) molecules and low retention of low molecular weight (LMW, < 1-kDa) molecules can be achieved at high concentration factor (cf) values in sampling mode or over long time scales in recirculation mode. The interactions between aquatic colloids and EDCs were studied by mixing EDCs, water and colloids previously isolated by CFUF for a certain duration, followed by the separation of the target compounds between the truly dissolved and colloid-bound phases by CFUF and analysis by gas chromatography-mass spectrometry (GC-MS). The kinetics of EDCs binding to colloids were relatively rapid, reaching equilibrium within 5 min. The mass balance of chosen EDCs through CFUF system was fully investigated, with good recovery for the relatively polar EDCs such as estrone and 17b-estradiol. Based on EDC sorption by colloids, the partition coefficient normalised to colloidal organic carbon content (Kcoc) was 8.85 B4 103, 1.50 B4 104, 8.85 B4 103, 4.87 B4 104 and 1.59 B4 104 mL/g for bisphenol A, estrone, 17b-estradiol, 17a-ethynylestradiol and 16a-hydroxyestrone, respectively, which are comparable with the values reported in the literature. In addition, it has been shown that the Kcoc values of EDCs were relatively independent of their octanol-water partition coefficient (Kow) values, suggesting the important role of different binding mechanisms other than non-specific hydrophobic interaction between EDCs and natural colloids. As the CFUF-GC-MS method can be used to quantify very low concentration of pollutants and is not limited to fluorescent compounds, it has the potential to be a widely applicable separation/analytical tool for determining the partition of organic pollutants between colloidal materials and dissolved phase.
JournalEnvironmental Science and Technology
PublisherAmerican Chemical Society
Department affiliated with
- Biology and Environmental Science Publications
NotesJZ directed the research and was the corresponding author. This is one of the first papers published describing a new method developed for determining the distribution of EDCs between dissolved and colloidal phases. The method laid a foundation for further research into EDC speciation and bioavailability in the aquatic environment.
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