Organophosphate esters in terrestrial environments of Fildes Peninsula, Antarctica: Occurrence, potential sources, and bioaccumulation.

Despite growing concerns regarding the long-range transport (LRT) and ecological risks of organophosphate esters (OPEs), information on the environmental behaviors of OPEs in polar terrestrial ecosystems remains inadequate. In the present study, 10 OPEs were analyzed in soil and vegetation samples collected from Fildes Peninsula, Antarctica. The OPE concentrations in Antarctic soils, mosses, and lichens ranged from 0.87 to 15.7 ng/g dry weight (dw), 9.8 to 113 ng/g dw, and 3.6 to 75.2 ng/g dw, respectively. Non-chlorinated OPEs predominated in terrestrial matrices, accounting for approximately 76 % of the OPE composition. Source identification indicated that OPE contamination in Antarctica likely resulted from local anthropogenic sources and LRT. Moreover, the bioaccumulation behavior of OPEs from soil to vegetation was assessed using bioconcentration factors (BCFs), revealing a significant non-linear trend of initial increase and subsequent decrease in BCFs relative to the lipophilicities of the octanol-air partition coefficient (log KOA) and octanol-water partition coefficient (log KOW). While low levels of OPEs in Antarctic terrestrial environments were reported in this study, their sustained inputs and potential ecological risks in polar regions warrant further attention.

Hexabromocyclododecanes in soils, plants, and sediments from Svalbard, Arctic: Levels, isomer profiles, chiral signatures, and potential sources.

This study investigated the occurrence, stereoisomeric behavior, and potential sources of hexabromocyclododecanes (HBCDs) in topsoil and terrestrial vegetation from Svalbard and ocean sediment samples from Kongsfjorden, an open fjord on the west coast of Spitsbergen. The mean levels of total concentrations (Σ3HBCDs) were comparable to those in other remote regions and were lower than those in source regions. Elevated proportions of α-HBCD with an average of 41% in the terrestrial samples and 25% in ocean sediments compared to those in commercial products (10-13% for α-HBCD) were observed, implying isomerization from γ- to α-HBCD in the Arctic environment. In addition, the extensive deviations of enantiomeric fractions (EFs) from the racemic values reflected the effect of biotransformation on HBCD accumulation. Linear correlation analysis, redundancy analysis, and back-trajectory were combined to infer possible HBCD sources, and the results showed the important role of global production and long-range environmental transport (LRET) for the entry of HBCDs into the Arctic at an early stage. To the best of our knowledge, this study represents the first report on the diastereoisomer- and enantiomer-specific profiles of HBCDs in the Arctic terrestrial environment and sheds light on the transport pathways and environmental fate for more effective risk management related to HBCDs in remote regions.

Assessment of interactions between elemental carbon and metals in black carbon: Hydroxyl radical generation and glutathione depletion.

Elemental carbon (EC) and metals are two important parts of atmospheric black carbon (BC). However, little information is available regarding the interaction between them and its impacts on the reactive oxygen species (ROS) formation and physiological antioxidants depletion. In this study, we chose six most frequently detected metals (Cu(Ⅱ), Fe(Ⅲ), Mn(Ⅱ), Cr(Ⅲ), Pb(Ⅱ) and Zn(Ⅱ)) in BC and examined their interactions with EC in the ROS generation and glutathione (GSH) oxidation. Results showed that only Cu(Ⅱ) and EC synergically promoted the GSH oxidation and hydroxyl radical (•OH) generation. Other five metals had negligible effects on the GSH oxidation regardless of the presence or absence of EC. The synergistic interaction between Cu(Ⅱ) and EC could be attributed to the superior electrical conductivity of EC. In the process, EC transferred electrons from the adjacent GSH to Cu(Ⅱ) through its graphitic carbon framework to yield Cu(Ⅰ) and GSH radical. Cu(Ⅰ) further reacted with dioxygen to generate •OH, which eventually led to the oxidation of GSH. Our results revealed a new driving force inducing the ROS formation and GSH depletion as well as provided novel insights into the risk assessment of BC.

Small extracellular vesicles' enrichment from biological fluids using an acoustic trap.

Small extracellular vesicles (sEVs), a form of extracellular vesicles, are lipid bilayered structures released by all cells. Large-scale studies on sEVs from clinical samples are necessary, but a major obstacle is the lack of rapid, reproducible, efficient, and low-cost methods to enrich sEVs. Acoustic microfluidics have the advantage of being label-free and biocompatible, which have been reported to successfully enrich sEVs. In this paper, we present a highly efficient acoustic microfluidic trap that can offer low and large volume compatible ways of enriching sEVs from biological fluids by flexible structure design. It uses the idea of pre-loading larger seed particles in the acoustic trap to enable sub-micron particle capturing. The microfluidic chip is actuated using a piezoelectric plate transducer attached to a silicon-glass bonding plate with circular cavities. Each cavity works as a resonant unit, excited at the frequency of both the half wave resonance in the main plane and inverted quarter wave resonance in the depth direction, which has the ability to strongly trap seed particles at the center, thereby improving the subsequent nanoparticle capture efficiency. Mean trapping efficiencies of 35.62% and 64.27% were obtained using 60 nm and 100 nm nanobeads, respectively. By the use of this technology, we have successfully enriched sEVs from cell culture conditioned media and blood plasma at a flow rate of 10 µL min-1. The isolated sEV subpopulations are characterized by NTA and TEM, and their protein cargo is determined by WB. This acoustic trapping chip provides a rapid and robust method to enrich sEVs from biofluids with high reproducibility and sufficient quantities. Therefore, it can serve as a new tool for biological and clinical research such as cancer diagnosis and drug delivery.

Bioaccumulation and Trophodynamics of Novel Brominated Flame Retardants (NBFRs) in Marine Food Webs from the Arctic and Antarctic Regions.

The pervasive contamination of novel brominated flame retardants (NBFRs) in remote polar ecosystems has attracted great attention in recent research. However, understanding regarding the trophic transfer behavior of NBFRs in the Arctic and Antarctic marine food webs is limited. In this study, we examined the occurrence and trophodynamics of NBFRs in polar benthic marine sediment and food webs collected from areas around the Chinese Arctic Yellow River Station (n = 57) and Antarctic Great Wall Station (n = 94). ∑7NBFR concentrations were in the range of 1.27-7.47 ng/g lipid weight (lw) and 0.09-1.56 ng/g lw in the Arctic and Antarctic marine biota, respectively, among which decabromodiphenyl ethane (DBDPE) was the predominant compound in all sample types. The biota-sediment bioaccumulation factors (g total organic carbon/g lipid) of NBFRs in the Arctic (0.85-3.40) were 4-fold higher than those in the Antarctica (0.13-0.61). Trophic magnification factors (TMFs) and their 95% confidence interval (95% CI) of individual NBFRs ranged from 0.43 (95% CI: 0.32, 0.60) to 1.32 (0.92, 1.89) and from 0.34 (0.24, 0.49) to 0.92 (0.56, 1.51) in the Arctic and Antarctic marine food webs, respectively. The TMFs of most congeners were significantly lower than 1, indicating a trophic dilution potential. This is one of the very few investigations on the trophic transfer of NBFRs in remote Arctic and Antarctic marine ecosystems, which provides a basis for exploring the ecological risks of NBFRs in polar regions.

A high-precision, effective method for extraction and identification of small-sized microplastics from soil.

A growing evidence showed that the terrestrial ecosystem was a greater sink for microplastics (MPs) compared with ocean. Owing to the limitation of pretreatment methods, there are few reports on the identification of small-sized MPs(<60 µm) in soil currently, which may led to an underestimation of the environmental risk of MPs in soil system. In this study, we established an efficient pretreatment method for MPs in soils by developing a novel device, Plastic Flotation and Separator system (PFSS). The device integrated the suspension, digestion and filtration procedures into one system, reducing the losses of pretreatment process. It was shown that the recovery of MPs with size of 45 µm was 90%, significantly surpassing that of the traditional pretreatment methods in this particle size range. Combined with the SEM-Raman technique, MPs with small size were accurately determined. This work provides an effective method for the extraction and determination of MPs in soils and is of significance for the risk assessment of MPs in soil system.