Remarkable Contamination of Short- and Medium-Chain Chlorinated Paraffins in Free-Range Chicken Eggs from Rural Tibetan Plateau.

Rapid social-economic development introduces modern lifestyles into rural areas, not only bringing numerous modern products but also new pollutants, such as chlorinated paraffins (CPs). The rural Tibetan Plateau has limited industrial activities and is a unique place to investigate this issue. Herein we collected 90 free-range chicken egg pool samples across the rural Tibetan Plateau to evaluate the pollution status of CPs. Meanwhile, CPs in related soils, free-range chicken eggs from Jiangxi, and farmed eggs from markets were also analyzed. The median concentrations of SCCPs (159 ng g-1 wet weight (ww)) and MCCPs (1390 ng g-1 ww) in Tibetan free-range chicken eggs were comparable to those from Jiangxi (259 and 938 ng g-1 ww) and significantly higher than those in farmed eggs (22.0 and 81.7 ng g-1 ww). In the rural Tibetan Plateau, the median EDI of CPs via egg consumption by adults and children were estimated to be 81.6 and 220.2 ng kg-1 bw day-1 for SCCPs and 483.4 and 1291 ng kg-1 bw day-1 for MCCPs, respectively. MCCPs might pose potential health risks for both adults and children in the worst scenario. Our study demonstrates that new pollutants should not be ignored and need further attention in remote rural areas.

Regulating Crystallization and Lead Leakage of Perovskite Solar Cell Via Novel Polyoxometalate-Based Metal-Organic Framework.

Despite the unprecedented progress in lead-based perovskite solar cells (PSCs), the toxicity and leakage of lead from degraded PSCs triggered by deep-level defects and poor crystallization quality increase environmental risk and become a critical challenge for eco-friendly PSCs. Here, a novel 2D polyoxometalate (POM)-based metal-organic framework (MOF) (C5 NH5 )4 (C3 N2 H5 )2 Zn3 (H8 P4 Mo6 O31 )2 ·2H2 O (POMOF) is ingeniously devised to address these issues. Note that the integration of POM endows POMOF with great advantages of electrical conductivity and charge mobility. Ordered POMOF induces the crystallization of high-quality perovskite film and eliminates lead-based defects to improve internal stability. The resultant PSCs achieve a superior power conversion efficiency (23.3%) accompanied by improved stability that maintains ≈90% of its original efficiency after 1600 h. Meanwhile, POMOF with phosphate groups effectively prevents lead leakage through in situ chemical anchoring and adsorption methods to reduce environmental risk. This work provides an effective strategy to minimize lead-based defects and leakage in sustainable PSCs through multi-functional POM-based MOF material.

Source Identification of Organophosphate Esters through the Profiles in Proglacial and Ocean Sediments from Ny-Ålesund, the Arctic.

Little is known about the sources and environmental behavior of organophosphate esters (OPEs) in the Arctic, especially their transformation products. The present study unprecedentedly investigated both 16 tri-OPEs and 8 di-OPEs in proglacial and ocean sediments from Ny-Ålesund, the Arctic. Mean concentrations of tri-OPEs and di-OPEs in proglacial sediments were 487 and 341 pg/g dry weight (dw), respectively, which were significantly lower than those in ocean sediments (1692 and 525 pg/g dw). Ocean sediments might be simultaneously influenced by long-range atmospheric transport (LRAT), oceanic transport, and human activities, whereas proglacial sediments, since they are isolated from human settlements, may be dominantly affected by LRAT. Such source difference was evidenced by the contamination profile of OPEs: chlorinated tri-OPEs with high environmental persistence and high LRAT were dominant in proglacial sediments (66%); however, weakly environmentally persistent and highly hydrophobic aryl tri-OPEs were dominant in ocean sediments (47%), which were plausibly from local emission sources due to their low LRAT potential. Di-OPEs in proglacial and ocean sediments were dominated by groups of parent tri-OPEs with strong photodegradability, such as alkyl (75%) and aryl (58%). A higher mean molar ratio of di-OPE/tri-OPE in the proglacial sediment (14) than that in the ocean sediment (2.2) may be related to its higher photodegradation than that of the ocean sediment.

Linking Transthyretin-Binding Chemicals and Free Thyroid Hormones: In Vitro to In Vivo Extrapolation Based on a Competitive Binding Model.

Large numbers of pollutants competitively inhibit the binding between thyroid hormones and transthyretin (TTR) in vitro. However, the impact of this unintended binding on free thyroid hormones in vivo has not yet been characterized. Herein, we established a quantitative in vitro to in vivo extrapolation (QIVIVE) method based on a competitive binding model to quantify the effect of TTR-binding chemicals on free thyroid hormones in human blood. Twenty-five TTR-binding chemicals including 6 hydroxyl polybromodiphenyl ethers (OH-PDBEs), 6 hydroxyl polychlorobiphenyls (OH-PCBs), 4 halogenphenols, 5 per- and polyfluorinated substances (PFASs), and 4 phenols were selected for investigation. Incorporating the in vitro binding parameters and human exposure data, the QIVIVE model could well predict the in vivo effect on free thyroid hormones. Co-exposure to twenty-five typical TTR-binding chemicals resulted in median increases of 0.080 and 0.060% in circulating levels of free thyroxine (FT4) and free triiodothyronine (FT3) in the general population. Individuals with occupational exposure to TTR-binding chemicals suffered 1.88-32.2% increases in free thyroid hormone levels. This study provides a quantitative tool to evaluate the thyroid-disrupting risks of TTR-binding chemicals and proposes a new framework for assessing the in vivo effects of chemical exposures on endogenous molecules.

Occurrence differences of hexachlorobutadiene and chlorobenzenes in road dust and roadside soil media in an industrial and residential mixed area in Eastern China.

The road dust and roadside soil can act as both sinks and sources of hexachlorobutadiene (HCBD) and chlorobenzenes (CBzs), but comparative research on these two adjacent media is extremely limited. In this study, HCBD and CBzs were simultaneously analyzed in road dust and roadside soil samples from an area containing both industrial factories and residential communities in Eastern China. The road dust there was found to have 2-6 times higher contents of HCBD (mean 1.14 ng/g, maximum 6.44 ng/g) and ∑Cl3-Cl6CBzs (22.8 ng/g, 90.6 ng/g) than those in the roadside soil. The spatial distributions of HCBD and CBzs in road dusts were affected by various types of sources, showing no significant discrepancy among the sites. On the contrast, HCBD and CBzs contamination in roadside soils occurring near several factories were strongly correlated to their industrial point sources. Risk assessments showed, at current contamination levels in the road dust and roadside soil, HCBD and CBzs are not likely to induce carcinogenic or non-carcinogenic risks to residents in the studied area. Nevertheless, road dust ingestion, as the major exposure pathway of HCBD and CBzs, should be avoided to reduce the exposure risk. These findings based on the contamination differences between two media provide a new perspective and evidence for screening important sources and exposure pathway of HCBD and CBzs, which would be helpful to their source identification and risk control.

Multifunctional MOF@COF Nanoparticles Mediated Perovskite Films Management Toward Sustainable Perovskite Solar Cells.

Although covalent organic frameworks (COFs) with high π-conjugation have recently exhibited great prospects in perovskite solar cells (PSCs), their further application in PSCs is still hindered by face-to-face stacking and aggregation issues. Herein, metal-organic framework (MOF-808) is selected as an ideal platform for the in situ homogeneous growth of a COF to construct a core-shell MOF@COF nanoparticle, which could effectively inhibit COF stacking and aggregation. The synergistic intrinsic mechanisms induced by the MOF@COF nanoparticles for reinforcing intrinsic stability and mitigating lead leakage in PSCs have been explored. The complementary utilization of π-conjugated skeletons and nanopores could optimize the crystallization of large-grained perovskite films and eliminate defects. The resulting PSCs achieve an impressive power conversion efficiency of 23.61% with superior open circuit voltage (1.20 V) and maintained approximately 90% of the original power conversion efficiency after 2000 h (30-50% RH and 25-30 °C). Benefiting from the synergistic effects of the in situ chemical fixation and adsorption abilities of the MOF@COF nanoparticles, the amount of lead leakage from unpackaged PSCs soaked in water (< 5 ppm) satisfies the laboratory assessment required for the Resource Conservation and Recovery Act Regulation.

Occurrence and risk assessment of organophosphate esters in global aquatic products.

Organophosphate esters (OPEs), as an important class of new pollutants, have been pervasively detected in global aquatic products, arousing widespread public concern due to their potential bioaccumulative behavior and consequent risks. With the continuous improvement of living standards of citizens, there have been constant increment of the proportion of aquatic products in diets of people. The levels of OPEs exposed to residents may also be rising due to the augmented consumption of aquatic products, posing potential hazards on human health, especially for people in coastal areas. The present study integrated the concentrations, profiles, bioaccumulation, and trophic transfer of OPEs in global aquatic products, including Mollusca, Crustacea, and fish, evaluated health risks of OPEs through aquatic products in daily diets by Mont Carol Simulation (MCS), and found Asia has been the most polluted area in terms of the concentration of OPEs in aquatic products, and would have been increasingly polluted. Among all studied OPEs, chlorinated OPEs generally showed accumulation predominance. It is worth noting that some OPEs were found bioaccumulated and/or biomagnified in aquatic ecosystems. Though MCS revealed relative low exposure risks of residents, sensitive and special groups such as children, adolescents, and fishermen may face more serious health risks than the average residents. Finally, knowledge gaps and recommendations for future research are discussed encouraging more long-term and systematic global monitoring, comprehensive studies of novel OPEs and OPEs metabolites, and more toxicological studies to completely evaluate the potential risks of OPEs.

Lanthanide 3D Supramolecular Framework Boosts Stable Perovskite Solar Cells with High UV Utilization.

In this work, the ligand-to-metal charge transition and Förster resonance energy transfer process is exploited to derive lanthanide-organic framework (Tb-cpon) modified perovskite solar cells (PSCs) with enhanced performance under UV irradiation. Tb-cpon-modified PSCs exhibit rapid response and reduced degradation due to energy downconversion facilitated by effective coupling of UV-sensitive chromophores to lanthanide luminescent centers, enhancing the spectral response range of the composite films. Furthermore, the characteristic changes of precursor particle sizes suggest formation of Tb-cpon adducts as intermediate products, leading to enhanced crystallinity and reduced defect concentrations in the Tb-cpon-perovskite hybrid film. Accordingly, the Tb-cpon-modified PSC devices obtain a champion efficiency up to 23.72% as well as a sensitive photovoltaic conversion even under pure UV irradiation. Moreover, the unencapsulated devices maintain more than 80% of the initial efficiency after continuous irradiation under a 310 nm UV lamp for 24 h (from the Au electrode side), compared to 21% for the control devices.

Toxic arsenic in marketed aquatic products from coastal cities in China: Occurrence, human dietary exposure risk, and coexposure risk with mercury and selenium.

To improve the accuracy of dietary risk assessment of arsenic (As) from aquatic products, toxic As species (As(III), As(V), monomethylarsonic acid [MMA], and dimethylarsinic acid [DMA]) and total As were analyzed in 124 marketed aquatic products from eight coastal cities in China. Distribution characteristics of Toxic As (the sum of the four toxic As species) in the samples and associated risk of human dietary exposure were emphatically investigated. The impact of cooccurrence of As and other chemical elements in the aquatic products was assessed based on our former results of mercury (Hg) and selenium (Se). Toxic As contents (maximum value 0.358 mg kg-1 wet weight) in the samples accounted for at most 14.1% of total As. DMA was the major component (mean proportion 50.8% for shellfish, 100% for fish) of Toxic As in aquatic products. Shellfish contained more Toxic As than fish did. Mean estimated daily intakes of Toxic As for the residents with aquatic product consumption rates of 46.1-235 g day-1 ranged from 0.034 to 0.290 µg kg-1 day-1. Potential health risk was indicated among those who greatly consumed aquatic products, as their target hazard quotient (THQ) and target cancer risk (TR) values exceeded safety thresholds (1 for THQ, 10-4 for TR). DMA and MMA exposure contributed to 3.42-7.72% of the THQToxic As. Positive correlations between concentrations of As and Hg (Fish: r = 0.47, p < 0.01; Shellfish: r = 0.60, p < 0.01), as well as between that of As and Se (Fish: r = 0.69, p < 0.01; Shellfish: r = 0.37, p < 0.01) were found in the samples. It requires attentions urgently that As and Hg coexposure through aquatic product consumption rose the sum THQ of Toxic As and methylmercury (MeHg) to approximately two to eight times as high as the THQToxic As.

Investigation on the Mechanism of Radical Intermediate Formation and Moderate Oxidation of Spiro-OMeTAD by the Synergistic Effect of Multisubstituted Polyoxometalates in Perovskite Solar Cells.

Conventional oxidation of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) by air would bring various drawbacks for perovskite solar cells (PSCs), such as low power conversion efficiency (PCE) and poor stability. Here, a series of heteroatom-substituted Keggin-type polyoxometalates (POMs), H4PMo11VO40 (PMo11V), H5PMo10V2O40 (PMo10V2), and H6PMo9V3O40 (PMo9V3) are prepared and applied as p-type dopants to realize quantitative and controllable oxidation of Spiro-OMeTAD under an inert condition. The possible mechanism and electron donor regions in the oxidation of Spiro-OMeTAD are investigated using two-dimensional nuclear magnetic resonance (NMR) spectra and the relationship between POM structures and the oxidation degree of Spiro-OMeTAD is proposed. In addition, the synergistic effect of heteroatoms makes V2-substituted PMo10V2 exhibit appropriate oxidation of Spiro-OMeTAD and promoted the highest efficient hole extraction as well as the decreased charge recombination. Therefore, the champion device doped with PMo10V2 shows a PCE of 20.41% and a superior open circuit voltage (Voc) of 1.133 V, surpassing that of the pristine device (18.61%). This work presents a fresh perspective to the controllable oxidation of Spiro-OMeTAD employing economical inorganic POM dopants, which would promote the commercialization of PSCs.

Chemical doping engineering by utilizing trilacunary Keggin polyoxometalates as a dopant for high performance perovskite solar cells.

Chemical doping engineering is an effective strategy to modify the hole transport layer (HTL) and achieve high-efficiency perovskite solar cells (PSCs). In this work, we synthesize an infrequent trilacunary Keggin type polyoxometalate Na10[Zn2(H2O)6(WO2)2(BiW9O33)2] (BiW9-Zn) and apply it as an additive to enhance the hole mobility and electrical conductivity of Spiro-OMeTAD based HTLs. Thanks to the strong electron-accepting properties of polyoxometalate molecules, the as-synthesized BiW9-Zn can directly oxidize Spiro-OMeTAD under an inert atmosphere and avoid the tedious long-term oxidation process. Therefore, the power conversion efficiency (PCE) of optimal PSCs with BiW9-Zn doping is enhanced from 17.58% (without doping) to 19.56% with a significantly improved fill factor and open-circuit voltage. In addition, the assembly repeatability and long-term stability of PSCs are also improved. This work demonstrates the potential of using polyoxometalates (POMs) as low-cost, efficient and highly flexible chemical dopants for HTLs, and more importantly paves a new route to enhance the performance of PSCs.

New Insight into the Lewis Basic Sites in Metal-Organic Framework-Doped Hole Transport Materials for Efficient and Stable Perovskite Solar Cells.

Currently, Spiro-OMeTAD is the most widely used hole transport material (HTM) in the best-performing perovskite solar cells (PSCs), resulting from its suitable energy level and facile processing. However, the intrinsic properties of organic molecules, such as low conductivity and a nonpolar contact interface, will limit the power conversion efficiency (PCE) and stability of Spiro-OMeTAD-based PSCs. Chemical doping could be an effective strategy to ameliorate the performance of Spiro-OMeTAD, and most of the dopants are designed for controllably oxidizing Spiro-OMeTAD. In this work, a highly stable metal-organic framework {[Zn(Hcbob)]·(solvent)}n (Zn-CBOB) with rod topology and Lewis basic sites is assembled and employed as a dopant for the hole transport layer. It is found that Zn-CBOB not only controllably oxidizes Spiro-OMeTAD and improves the conductivity of the HTM but also passivates the surface traps of the perovskite film by coordinating with Pb2+. The Zn-CBOB-doped PSCs achieved a remarkable PCE of 20.64%. In addition, the hydrophobicity of Zn-CBOB can prevent water from destroying the perovskite layer, which helps elevate the stability of PSCs.