Occurrence and distribution of estrogenic substances in the northern South China Sea.

Estrogenic substances are today among the contaminants of emerging concern. Besides naturally occurring estrogens, other natural and synthetic substances can mimic a hormonal action due to their structural resemblance to hormones, possibly affecting the endocrine system of living organisms. Estrogens have been detected in inland water bodies such as influents and effluents of waste water treatment plants as well as in rivers, but data on their distribution and variability in the marine ecosystem are still limited. Surface water samples obtained during two research cruises on the northern shelf of the South China Sea (SCS) near the Pearl River Estuary, in September 2018 and in August 2019, were investigated for estrogenic substances, namely estrone (E1), 17ß-estradiol (E2), 17α-ethinylestradiol (EE2), genistein (GEN), daidzein (DAI) and zearalenone (ZEN). Among the target analytes, the natural hormones E1 and E2, as well as the synthetic EE2, were the most abundant with maximum concentrations of 1.1 ng L-1, 0.7 ng L-1 and 0.6 ng L-1, respectively. Of substances produced by plants and fungi, GEN, DAI and ZEN, only GEN was detected (1.2 ng L-1). High concentrations occurred predominantly close to the coast, which was also reflected in the calculated estradiol equivalent quotients (up to 1.4 ng L-1). In general, the distribution of estrogenic substances observed in both years shows a regional and inter-annual variability consistent with the modeled surface current data for the SCS. Regarding single estrogenic compounds and estradiol equivalents, marine organisms in the northern SCS might be exposed to high potential risk.

UV-Polymerized Vinylimidazolium Ionic Liquids for Permselective Membranes.

Ionic liquids are highly charged compounds with increasing applications in material science. A universal approach to synthesize free-standing, vinylalkylimidazolium bromide-containing membranes with an adjustable thickness is presented. By the variation of alkyl side chains, membrane characteristics such as flux and mechanical properties can be adjusted. The simultaneous use of different ionic liquids (ILs) in the synthesis can also improve the membrane properties. In separation application, these charged materials allowed us to retain charged sugars, such as calcium gluconate, by up to 95%, while similar neutral compounds such as glucose passed the membrane. An analysis of the surface conditions using atomic force microscopy (AFM) confirmed the experimental data and explains the decreasing permeance and increased retention of the charged sugars.

Abundance and characteristics of microfibers detected in sediment trap material from the deep subtropical North Atlantic Ocean.

Plastics and microplastics increasingly gain importance due to their perils and wide distribution in the marine environment. Microfibers account for the largest percentage of anthropogenic-induced microparticles, which inter alia, consist of plastic, and are found in deep-sea sediments. However, the sinking of fibers from the surface through the water column to the seafloor is still poorly understood. The present study investigates microfibers extracted from sediment trap samples, which were deployed in the North Atlantic Subtropical Gyre (NASG). The average result of eleven analyzed samples showed 913 microfibers per gram of collected particle flux material, with a predominant fiber length shorter than 1 mm (75.6%) and a distribution maximum between 0.2 and 0.4 mm. Further, the average number of microfibers found in this study was used to derive microfiber fluxes for the NASG based on the deployment time of the sediment trap. Extrapolating the computed flux of 94 microfibers m-2 day-1 to the entire NASG area would correspond to a total microfiber mass flux of 9800 t a-1 or 73 × 1013 microfibers a-1 of sinking microfibers through the water column. These findings offer an extended application of sediment traps to monitor microfiber fluxes, which reveals the opportunity to investigate the mechanism driving sinking of microfibers and microplastics into the deep open ocean.