Hazard profiles, distribution trends, and sources tracing of rare earth elements in dust of kindergartens in Beijing.

Children, the most vulnerable group in urban populations, are susceptible to the effects of pollution in urban environments. It is significant to evaluate the influence of rare earth elements (REEs) from kindergartens dust (KD) in Beijing on children's health. This study collected surface dust from 73 kindergartens in 16 districts of the mega-city of Beijing, and the concentrations of 14 REEs in KD, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, were detected. The contamination levels, source apportionment, and health exposure risk of REEs were comprehensively investigated. The results indicate that the contamination levels of 14 REEs are within the acceptable range. Nevertheless, Eu, Ce, La, Pr, Nd, Gd, and Sm show high enrichment due to anthropogenic influence. Besides, KD is rich in light rare earth elements (LREEs) (90.97 mg kg-1) compared to heavy rare earth elements (HREEs) (8.65 mg kg-1). The distribution parameter patterns of REEs suggest that complicated anthropogenic sources influence the enrichment of REEs in KD. The main sources of REEs in KD include natural sources (40.64%), mixed high-tech industries and construction (33.89%), and mixed coal-fired, historical industrial, and transportation sources (26.47%). The primary pathway for daily intake of REEs in children is through ingestion, which presents a low but not negligible health risk. This study provides guidance for the effective risk management of REEs in KD.

Remarkable contamination characteristics, potential hazards and source apportionment of heavy metals in surface dust of kindergartens in a northern megacity of China.

It is essential to understand the impact of heavy metals (HMs) present in the surface dust (SD) of kindergartens on children, who are highly sensitive to contaminated dust in cities in their growth stage. A study was conducted on 11 types of HMs present in the SD of 73 kindergartens in Beijing. This study aims to assess the pollution levels and sources of eleven HMs in Beijing's kindergartens surface dust (KSD), and estimate the potential health risks in different populations and sources. The results indicate that Cd has the highest contamination in the KSD, followed by Pb, Zn, Ni, Ba, Cr, and Cu. The sources of these pollutants are identified as industrial sources (23.7%), natural sources (22.1%), traffic sources (30.4%), and construction sources (23.9%). Cancer risk is higher in children (4.02E-06) than in adults (8.93E-06). Notably, Cr is the priority pollutant in the KSD, and industrial and construction activities are the main sources of pollution that need to be controlled. The pollution in the central and surrounding areas is primarily caused by historical legacy industrial sites, transportation, urban development, and climate conditions. This work provides guidance to manage the pollution caused by HMs in the KSD of Beijing. ENVIRONMENTAL IMPLICATION: Children within urban populations are particularly sensitive to pollutants present in SD. Prolonged exposure to contaminated SD significantly heightens the likelihood of childhood illnesses. The pollution status and potential health risks of HMs within SD from urban kindergartens are comprehensively investigated. Additionally, the contributions from four primary sources are identified and quantified. Furthermore, a pollution-source-oriented assessment is adopted to clearly distinguish the diverse impacts of different sources on health risks, and the priority pollutants and sources are determined. This work holds pivotal importance for risk management, decision-making, and environmental control concerning HMs in KSD.

Source partitioning using phosphate oxygen isotopes and multiple models in a large catchment.

Excessive phosphorus (P) loadings cause major pollution concerns in large catchments. Quantifying the point and nonpoint P sources of large catchments is essential for catchment P management. Although phosphate oxygen isotopes (δ18O(PO4)) can reveal P sources and P cycling in catchments, quantifying multiple P sources in a whole catchment should be a research focus. Therefore, this study aimed to quantitatively identify the proportions of multiple potential end members in a typical large catchment (the Yangtze River Catchment) by combining the phosphate oxygen isotopes, land use type, mixed end-element model, and a Bayesian model. The δ18O(PO4) values of river water varied spatially from 4.9‰ to18.3‰ in the wet season and 6.0‰ to 20.9‰ in the dry season. Minor seasonal differences but obvious spatial changes in δ18O(PO4) values could illustrate how human activity changed the functioning of the system. The results of isotopic mass balance and the Bayesian model confirmed that controlling agricultural P from fertilizers was the key to achieving P emission reduction goals by reducing P inputs. Additionally, the effective rural domestic sewage treatment, development of composting technology, and resource utilization of phosphogypsum waste could also contribute to catchment P control. P sources in catchment ecosystems can be assessed by coupling an isotope approach and multiple-models.

Analysis of the Plasmid-Based ts-Mutant ΔfabA/pTS-fabA Reveals Its Lethality under Aerobic Growth Conditions That Is Suppressed by Mild Overexpression of desA at a Restrictive Temperature in Pseudomonas aeruginosa.

It is uncertain whether PA1610|fabA is essential or dispensable for growth on LB-agar plates under aerobic conditions in Pseudomonas aeruginosa PAO1. To examine its essentiality, we disrupted fabA in the presence of a native promoter-controlled complementary copy on ts-plasmid. In this analysis, we showed that the plasmid-based ts-mutant ΔfabA/pTS-fabA failed to grow at a restrictive temperature, consistent with the observation by Hoang and Schweizer (T. T. Hoang, H. P. Schweizer, J Bacteriol 179:5326-5332, 1997, https://doi.org/10.1128/jb.179.17.5326-5332.1997), and expanded on this by showing that ΔfabA exhibited curved cell morphology. On the other hand, strong induction of fabA-OE or PA3645|fabZ-OE impeded the growth of cells displaying oval morphology. Suppressor analysis revealed a mutant sup gene that suppressed a growth defect but not cell morphology of ΔfabA. Genome resequencing and transcriptomic profiling of sup identified PA0286|desA, whose promoter carried a single-nucleotide polymorphism (SNP), and transcription was significantly upregulated (level increase of >2-fold, P < 0.05). By integration of the SNP-bearing promoter-controlled desA gene into the chromosome of ΔfabA/pTS-fabA, we showed that the SNP is sufficient for ΔfabA to phenocopy the sup mutant. Furthermore, mild induction of the araC-PBAD-controlled desA gene but not desB rescued ΔfabA. These results validated that mild overexpression of desA fully suppressed the lethality but not the curved cell morphology of ΔfabA. Similarly, Zhu et al. (Zhu K, Choi K-H, Schweizer HP, Rock CO, Zhang Y-M, Mol Microbiol 60:260-273, 2006, https://doi.org/10.1111/j.1365-2958.2006.05088.x) showed that multicopy desA partially alleviated the slow growth phenotype of ΔfabA, the difference in which was that ΔfabA was viable. Taken together, our results demonstrate that fabA is essential for aerobic growth. We propose that the plasmid-based ts-allele is useful for exploring the genetic suppression interaction of essential genes of interest in P. aeruginosa. IMPORTANCE Pseudomonas aeruginosa is an opportunistic pathogen whose multidrug resistance demands new drug development. Fatty acids are essential for viability, and essential genes are ideal drug targets. However, the growth defect of essential gene mutants can be suppressed. Suppressors tend to be accumulated during the construction of essential gene deletion mutants, hampering the genetic analysis. To circumvent this issue, we constructed a deletion allele of fabA in the presence of a native promoter-controlled complementary copy in the ts-plasmid. In this analysis, we showed that ΔfabA/pTS-fabA failed to grow at a restrictive temperature, supporting its essentiality. Suppressor analysis revealed desA, whose promoter carried a SNP and whose transcription was upregulated. We validated that both the SNP-bearing promoter-controlled and regulable PBAD promoter-controlled desA suppressed the lethality of ΔfabA. Together, our results demonstrate that fabA is essential for aerobic growth. We propose that plasmid-based ts-alleles are suitable for genetic analysis of essential genes of interest.

Effects of non-invasive brain stimulation (NIBS) for executive function on subjects with ADHD: a protocol for a systematic review and meta-analysis.

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder with a high risk of multiple mental health and social difficulties. Executive function domains are associated with distinct ADHD symptom burdens. Non-invasive brain stimulation (NIBS) mainly includes repetitive transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), which is a promising technique, but its impact on the executive function of ADHD is uncertain. Therefore, the aim of this systematic review and meta-analysis is to derive solid and updated estimates on the effect of NIBS on executive function in children/adults with ADHD. METHODS AND ANALYSIS: A systematic search will be performed through EMBASE, MEDLINE, PsycINFO and Web of Science databases from inception until 22 August 2022. Handsearching of grey literature and the reference lists of selected articles will also be conducted. Empirical studies assessing the effect of NIBS (TMS or tDCS) on executive function in children or adults with ADHD will be included. Two investigators will independently perform literature identification, data extraction and risk of bias assessment. Relevant data will be pooled by a fixed-effects or random-effects model according to I2 statistic. Sensitivity analysis will be performed to test the robustness of the pooled estimates. Subgroup analyses will be conducted to investigate the potential heterogeneity. This protocol will generate a systematic review and meta-analysis that comprehensively synthesises the evidence on the NIBS treatment of executive function deficit of ADHD.Ethics approval is not required as this is a protocol for a systematic review of published literature. The results will be submitted to a peer-reviewed journal or a conference. PROSPERO REGISTRATION NUMBER: CRD42022356476.

Insights into Health Risks of Face Paint Application to Opera Performers: The Release of Heavy Metals and Stage-Light-Induced Production of Reactive Oxygen Species.

Face paints used by opera performers have been shown to contain high levels of heavy metals. However, whether frequent exposure, via dermal contact and inadvertent oral ingestion, results in occupational diseases is unknown, as is the potential exacerbation of toxicity by high-intensity irradiation from stage lights. In this study, we examined the release of Cr, Cu, Pb, and Zn from 40 face paints and the consequent health risks posed by different practical scenarios involving their use. The results showed that the in vitro bioaccessibility (IVBA) of Cr, Cu, Pb, and Zn in the tested products was, on average, 7.0, 5.5, 19.9, and 7.9% through oral ingestion and 1.1, 2.2, 1.6, and 1.2% through dermal contact, respectively. Stage light irradiation significantly increased the IVBA associated with dermal contact, to the average of 4.8, 34.9, 5.7, and 1.9% for Cr, Cu, Pb, and Zn, respectively. The increase was mainly due to the light-induced generation of reactive oxygen species, particularly hydroxyl free radicals. The vitality and transcriptional response of 3D skin models as well as a quantitative risk assessment of skin sensitization indicated that dermal contact with face paints may induce predictable skin damage and potentially other skin diseases. Long-term exposure to face paints on stage may also pose a non-carcinogenic health risk. The demonstrated health risks to opera performers of face paint exposure should lead to strict regulations regarding the content of theatrical face paints.

Variations and its driven factors of anthropogenic nitrogen loads in the Yangtze River Economic Belt during 2000-2019.

Since the millennium, China has economically taken off with rapid urbanization, and anthropogenic nitrogen emission intensity has undergone remarkable changes. To better understand the impact of urbanization on anthropogenic nitrogen, this study calculated the spatio-temporal heterogeneity of anthropogenic nitrogen in the Yangtze River Economic Belt (YREB) since 2000, based on the estimation, using obstacle analysis to quantify the driving of industry and agriculture on N growth and using the gray model to analyze the impact of urbanization on N changes. Additionally, using the environmental pressure model to predict the future N load. The results indicated N load in the YREB increased rapidly from 21.4 Tg in 2001 to a peak of 24.5 Tg in 2012 and then decreased to 22.2 Tg in 2019. Although N flux gradually increased from the west to the east of the YREB, the growth rate had an opposite trend with a negative growth in the eastern region. Hotspots are mainly concentrated in urban agglomerations, which contributed to ~ 60% N load of the YREB, and the YREB contributed to ~ 90% N load of the Yangtze River Basin. Obstacle degree scores indicated wastewater was a major industrial driver of N growth before 2010, and then became waste gas; increased mechanization and fertilizer control effectively reduced nitrogen emissions during agricultural development. The gray analysis of urbanization indicated urban population, industry, and services had the strongest correlation with N load changes. Scenario simulations suggest N loads of the YREB remain at a high level by 2030; however, there are still opportunities to effectively control N growth through high technological innovation and reducing the proportion of industry under an enormous population. This research contributes to a better understanding of the impact of urbanization on anthropogenic nitrogen and helps developing countries to precisely control nitrogen hotspots and sources.

Neuro- and hepato-toxicity of polystyrene nanoplastics and polybrominated diphenyl ethers on early life stages of zebrafish.

Nanoplastics (NPs) are good carriers of persistent organic pollutants (POPs) such as polybrominated diphenyl ethers (PBDEs) and can modify their bioavailability and toxicity to aquatic organisms. This study highlights the single and combined toxic effects of polystyrene nanoplastics (PS-NPs) and 2,2 ',4,4 '-tetrabromodiphenyl ether (BDE-47, one of the major PBDE congeners) on zebrafish embryos after an exposure of up to 120 hpf. Our results showed that PS-NPs and BDE-47 formed larger particle aggregates during co-exposure, which attached to the surface of the yolk membrane and even changed its structure, and these particles also bioaccumulated in the intestine of zebrafish larvae, compared with the PS-NPs single exposure. Further, the co-exposure significantly increased mortality, accelerated voluntary movements, enhanced hatching rate, and decreased heart rate. Hepatoxicity analyses revealed that the mixture exposure induced a darker/browner liver colour, atrophied liver and greater hepatotoxicity in zebrafish larvae. In addition to increased ROS accumulation, the reduced expression of the antioxidant gpx1a gene and increased expression of cyp1a1 were found after co-treatment. Moreover, ache and chrn7α genes associated with neurocentral development, were significantly downregulated, mainly in the co-exposure group. In conclusion, simultaneous exposure to PS-NPs and BDE-47 exacerbated oxidative stress, developmental impacts, hepatotoxicity, and neurodevelopmental toxicity in zebrafish larvae. Therefore, neurotoxic effects of complex chemical interactions between PS-NPs and persistent organic pollutants in freshwater environments should be paid more attention.

Polyaspartic acid enhances the Cd phytoextraction efficiency of Bidens pilosa by remolding the rhizospheric environment and reprogramming plant metabolism.

The green soil chelator polyaspartic acid (PASP) can enhance heavy metal phytoextraction efficiency, but the potential mechanisms are not clearly understood from the whole soil-plant system. In this study, we explored the effects and potential mechanisms of PASP addition in soils on plant growth and cadmium (Cd) uptake in the Cd hyperaccumulator Bidens pilosa by analysing variations in chemical elements, rhizospheric microbial community, and plant metabolomics. The results showed that PASP significantly promoted the biomass yield and Cd concentration in B. pilosa, leading to an increase in the total accumulated Cd by 46.4% and 76.4% in shoots and 124.7% and 197.3% in roots under 3 and 6 mg kg-1 PASP addition, respectively. The improved soil-available nutrients and enriched plant growth-promoting rhizobacteria (e.g., Sphingopyxis, Sphingomonas, Cupriavidus, Achromobacter, Nocardioides, and Rhizobium) were probably responsible for the enhanced plant growth after PASP addition. The increase in Cd uptake by plants could be due to the improved rhizosphere-available Cd, which was directly activated by PASP and affected by the induced rhizobacteria involved in immobilizing/mobilizing Cd (e.g., Sphingomonas, Cupriavidus, Achromobacter, and Rhizobium). Notably, PASP and/or these potassium (K)-solubilizing rhizobacteria (i.e., Sphingomonas, Cupriavidus, and Rhizobium) highly activated rhizosphere-available K to enhance plant growth and Cd uptake in B. pilosa. Plant physiological and metabolomic results indicated that multiple processes involving antioxidant enzymes, amino acids, organic acids, and lipids contributed to Cd detoxification in B. pilosa. This study provides novel insights into understanding how soil chelators drive heavy metal transfer in soil-plant systems.

Recent Advances of Biochar-Based Electrochemical Sensors and Biosensors.

In the context of accelerating the global realization of carbon peaking and carbon neutralization, biochar produced from biomass feedstock via a pyrolysis process has been more and more focused on by people from various fields. Biochar is a carbon-rich material with good properties that could be used as a carrier, a catalyst, and an absorbent. Such properties have made biochar a good candidate as a base material in the fabrication of electrochemical sensors or biosensors, like carbon nanotube and graphene. However, the study of the applications of biochar in electrochemical sensing technology is just beginning; there are still many challenges to be conquered. In order to better carry out this research, we reviewed almost all of the recent papers published in the past 5 years on biochar-based electrochemical sensors and biosensors. This review is different from the previously published review papers, in which the types of biomass feedstock, the preparation methods, and the characteristics of biochar were mainly discussed. First, the role of biochar in the fabrication of electrochemical sensors and biosensors is summarized. Then, the analytes determined by means of biochar-based electrochemical sensors and biosensors are discussed. Finally, the perspectives and challenges in applying biochar in electrochemical sensors and biosensors are provided.

Toxic effects of polystyrene nanoplastics and polybrominated diphenyl ethers to zebrafish (Danio rerio).

Nanoplastics (NPs) are good carriers of persistent organic pollutants (POPs) such as polybrominated diphenyl ethers (PBDEs), and can alter their bioavailability and toxic impacts to aquatic organisms. This study highlights the single and combined toxic effects of polystyrene nanoplastics (PS-NPs) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47, one of the dominant congeners of PBDEs) on zebrafish embryos after an exposure duration of up to 120 hpf. Results showed that PS-NPs and BDE-47 co-exposure exacerbated the morphological deformities in terms of pericardial edema, yolk sac edema and curved tail in zebrafish larvae. Compared to BDE-47 single exposure, the combined exposure caused lower survival rates, shorter body lengths, and accelerated spontaneous movements. Further, PS-NPs were quickly aggregated on the surface of the embryonic chorions covered almost the entire membrane at 12 and 48 hpf, and concentration dependent accumulation was also found in the brain, mouth, trunk, gills, heart, liver and gastrointestinal tract at the larval stages. During the recovery period (7 days), PS-NPs were released from all the organs, with the highest elimination from the gastrointestinal tract. Histopathological examination revealed that co-exposure caused greater damage to retinal structures, muscle fibers and cartilage tissues. Responses of hypothalamic-pituitary-thyroid axis (CRH, TSHß, NIS, TTR, Dio2, TG, TRα and TRß) and reproduction (Esr2 and Vtg1) related genes were also investigated, and results showed that the co-exposure induced more significant upregulated expressions of TSHß, TG, Doi 2, and TRß, compared to BDE-47 single exposure. In conclusion, co-exposure to NPs and BDE-47 exacerbated developmental and thyroid toxicity in zebrafish, generally elucidating the toxicological effects mediated by complex chemical interactions between NPs with POPs in the freshwater environment.

Tracing phosphorus cycle in global watershed using phosphate oxygen isotopes.

The Phosphorus (P) cycle is a crucial biochemical process in the earth system. However, an extensive increase of P input into watersheds destroyed the ecosystem. To explore the effects of internal P loading and external P input in global watersheds, we reviewed the research progress and synthesized the isotope data of experimental results from literatures. An integrated result of the observational and experimental studies revealed that both internal P and external P largely contribute to watershed P loadings in watersheds. Internal P can be released to the overlying water during sediment resuspension process and change of redox conditions near the sediment-water interface. Growing fertilizer application on farmlands to meet food demand with population rise and diet improvement contributed to an huge increase of external P input to watersheds. Therefore, water quality cannot be improved by only reducing internal P or external P loadings. In addition, we found that phosphate oxygen isotope technology is an effectively way to trace the P biogeochemical cycle in watersheds. To better predict the dynamic of P in watersheds, future research integrating oxygen isotope fractionation mechanisms and phosphate oxygen isotope technology would be more effective.

An integrated approach to quantify ecological and human health risks of soil heavy metal contamination around coal mining area.

Soil heavy metals harm ecological biodiversity and human health, and quantifying the risks more accurately is still obscure. In this study, a network environ analysis was applied to quantify risks between ecological communities based on control allocation and human health risk models to calculate human health exposure risks from soil heavy metals around Greenside coal mining in South Africa. Ecological and human health risks were apportioned using PMF model. Results showed assessed heavy metals (mean) exceeded local background content with a cumulative of moderately polluted using pollution load index (PLI). Total initial risk (Ri), the risk to biological organisms from direct soil exposure, was 0.656 to vegetation and 1.093 to soil microorganisms. Risk enters the food web via vegetation and harms the whole system. Integrated risks (initial, direct, and indirect) to vegetation, herbivores, soil microorganisms, and carnivores were 0.656, 0.125, 1.750, and 0.081, respectively, revealing that soil microorganisms are the most risk receptors. Total Hazard Index (HIT) was <1 for adults (0.574) whereas >1 for children (4.690), signifying severe non-cancer effects to children. Total cancer risk (TCR) to children and adults surpassed the unacceptable limit (1.00E-04). Comparatively, Cr is a high-risk metal accounted for 63.24% (adults) and 65.88% (children) of the HIT and 92.98% (adults) and 91.31% (children) of the TCR. Four sources were apportioned. Contributions to Ri (soil microorganisms and vegetation) from F3 (industrial), F4 (atmospheric), F2 (coal mining), and F1 (natural) were 42.20%, 24.56%, 23.55%, and 9.68%, respectively. The non-cancer risk from F3 (37.67% to adults and 38.40% to children) was dominant, and TCR to children from the sources except F1 surpassed the unacceptable limit. An integrated approach of risk quantification is helpful in managing risks and reducing high-risk pollution sources to better protect the environment and human health.

Sustainable Solar Evaporation while Salt Accumulation.

Solar-driven water evaporation, as a cost-effective and eco-friendly way to produce high-quality freshwater from saline water, is a burgeoning and promising force in the battle against global thirst. However, unsustainable vapor generation caused by salt accumulation has always plagued researchers. Here, it is revealed that a solar thermal photo vapor generator (STPV), which utilizes infrared photons as a heat source, can evaporate water stably in the presence of salt accumulation. Thanks to the low reflection of the wet salt in the infrared band and the porous structure of the salt layer, the energy can be used effectively and the vapor escapes without hindrance. The STPV evaporates water at a stable rate of 1.04-1.19 kg m-2 h-1 under 2 sun illumination for 8 h in a highly concentrated sea salt solution (20 wt %). In contrast, the evaporation rate of conventional solar thermal vapor generators (STVs) decreased by >50% in 1 h and ≈70% in 8 h. This finding could inspire the future development of more advanced solar evaporators so as to ease the global water scarcity.

Human-driven spatiotemporal distribution of phosphorus flux in the environment of a mega river basin.

Large river basins transport considerable nutrients to the ocean every year. However, phosphorus (P) generated by human activities not only threatens aquatic ecosystem health in the river basin, but also has a negative effect on the estuary water environment. To better understand the environmental effects of anthropogenic P in a mega basin, we examined its inputs and distribution characteristics, and analyzed the factors driving it in the Yangtze River Basin (YRB) and sub-catchments. Anthropogenic P flux in the sub-catchments gradually increased from upper to lower reaches, and hotspots were primarily concentrated in traditional agricultural areas such as the Sichuan Basin and the Middle-Lower Yangtze plains. Agricultural sources were the main anthropogenic P inputs, of which fertilizer P was the leading contributor and driver of P changes, but livestock manure also accounted for a high proportion. Presently, anthropogenic P inputs in the YRB are considerably higher than in other parts of the world. Although long-distance transportation allows some P from the entire basin to be deposited in freshwater, a large amount of P still reaches the estuary and has a negative effect on water quality, outweighing the influence of local coastal inputs. To maintain the ecological health of the river basin and estuary, it will be necessary to further improve P utilization efficiency and encourage greater cooperation between different regions in the river basin.

Low Concentrations of Silver Nanoparticles and Silver Ions Perturb the Antioxidant Defense System and Nitrogen Metabolism in N2-Fixing Cyanobacteria.

Although toxic effects of silver nanoparticles (AgNPs) on aquatic organisms have been extensively reported, responses of nitrogen-fixing cyanobacteria to AgNPs/Ag+ under environmentally relevant concentrations are largely unknown. Here, cyanobacteria were exposed to different concentrations of AgNPs (0.01, 0.1, and 1 mg/L) or Ag+ (0.1, 1, and 10 µg/L) for 96 h. The impacts of AgNPs and Ag+ on photosynthesis and N2 fixation in cyanobacteria (Nostoc sphaeroides) were evaluated. In addition, gas chromatography-mass spectrometry (GC-MS)-based metabolomics was employed to give an instantaneous snapshot of the physiological status of the cells under AgNP/Ag+ exposure. Exposure to high doses of AgNPs (1 mg/L) or Ag+ (10 µg/L) caused growth inhibition, reactive oxygen species overproduction, malondialdehyde accumulation, and decreased N2 fixation. In contrast, low doses of AgNPs (0.01 and 0.1 mg/L) and Ag+ (0.1 and 1 µg/L) did not induce observable responses. However, metabolomics revealed that metabolic reprogramming occurred even at low concentrations of AgNP and Ag+ exposure. Levels of a number of antioxidant defense-related metabolites, especially phenolic acid and polyphenols (gallic acid, resveratrol, isochlorogenic acid, chlorogenic acid, cinnamic acid, 3-hydroxybenzoic acid, epicatechin, catechin, and ferulic acid), significantly decreased in response to AgNPs or Ag+. This indicates that AgNPs and Ag+ can disrupt the antioxidant defense system and disturb nitrogen metabolism even at low-dose exposure. Metabolomics was shown to be a powerful tool to detect "invisible" changes, not observable by typical phenotypic-based endpoints.

Hafnium isotope constraints on the nature of the mantle beneath the Southern Lau basin (SW Pacific).

New Hf isotope data provide new insights into the nature of the mantle beneath the southern Lau basin, adding new constraints on the displacement process of the Pacific mid-ocean ridge basalt (MORB)-type mantle by the Indian MORB-type mantle. The Hf isotopic ratios (176Hf/177Hf) of submarine lavas from the eastern Lau spreading center (ELSC) range from 0.283194 (εHf = 14.92) to 0.283212 (εHf = 15.54), with an average value of 0.283199 (εHf = 15.11) whereas those from the Valu Fa ridge (VFR) vary from 0.283221 (εHf = 15.88) to 0.283200 (εHf = 15.14), with an average of 0.283214 (15.61), indicating that ELSC lavas have a slightly more radiogenic Hf isotopic composition than VFR lavas. In contrast to the results from previous studies, the new Hf analyses combined with previous Nd isotope data clearly show that both VFR and ELSC have the distinct Hf-Nd isotope composition of the so-called DUPAL isotopic anomaly in the Indian MORB-type mantle. The DUPAL isotopic signature at VFR demonstrates for the first time that the inflow of the Indian MORB-type mantle has reached the southern tip of tectonic propagation in the southern Lau basin.

Foliar Application of SiO2 Nanoparticles Alters Soil Metabolite Profiles and Microbial Community Composition in the Pakchoi (Brassica chinensis L.) Rhizosphere Grown in Contaminated Mine Soil.

Silica nanoparticles (SiO2-NPs) are promising in nanoenabled agriculture due to their large surface area and biocompatible properties. Understanding the fundamental interaction between SiO2-NPs and plants is important for their sustainable use. Here, 3 week-old pakchoi (Brassica chinensis L.) plants were sprayed with SiO2-NPs every 3 days for 15 days (5 mg of SiO2-NPs per plant), after which the phenotypes, biochemical properties, and molecular responses of the plants were evaluated. The changes in rhizosphere metabolites were characterized by gas chromatography-mass spectrometry (GC-MS)-based metabolomics, and the response of soil microorganisms to the SiO2-NPs were characterized by high-throughput bacterial 16S rRNA and fungal internal transcribed spacer (ITS) gene sequencing. The results showed that the SiO2-NP spray had no adverse effects on photosynthesis of pakchoi plants nor on their biomass. However, the rhizosphere metabolite profile was remarkably altered upon foliar exposure to SiO2-NPs. Significant increases in the relative abundance of several metabolites, including sugars and sugar alcohols (1.3-9.3-fold), fatty acids (1.5-18.0-fold), and small organic acids (1.5-66.9-fold), and significant decreases in the amino acid levels (60-100%) indicated the altered carbon and nitrogen pool in the rhizosphere. Although the community structure was unchanged, several bacterial (Rhodobacteraceae and Paenibacillus) and fungal (Chaetomium) genera in the rhizosphere involved in carbon and nitrogen cycles were increased. Our results provide novel insights into the environmental effects of SiO2-NPs and point out that foliar application of NPs can alter the soil metabolite profile.

Heavy metals in face paints: Assessment of the health risks to Chinese opera actors.

The actors in Chinese operas are exposed to heavy metals through the face paints that they use but the resulting health risks are unknown. We therefore conducted a survey of face paint use by Chinese opera actors and then assayed 91 paint samples of various paint brands and colors for their contents of eight heavy metals. The potential health risks of heavy metal exposure due to face paint use were determined as well. The average concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were 1.8, 0.6, 4.4, 23.1, 610, 7.6, 16.2, and 10,415 µg/g, respectively, and at least four of the eight elements were detected in all samples. Samples from the most frequently paint brands were the most highly contaminated, especially with Zn, whose mass contribution was extremely high (18.3%). Moreover, contamination of the paint was color-specific, with significantly higher heavy metal levels in brown (As, Cr, and Ni), black (Co and Zn), red (Pb), and green (Cu) paints. The total carcinogenic risk posed by the metals in 25 paint samples ranged between 0.01% and 0.96%, with the highest risk that of Cr. Thus, lifetime exposure to Cr-containing paints would result in a high probability of the actor developing cancer. The findings of our study highlight the need for Chinese regulations addressing the heavy metals in face paints, especially Cr. Capsule: Chinese opera actors have a high probability of developing cancer due to a lifetime exposure to high levels of heavy metals in their face paints.