Enhanced Formation of 6PPD-Q during the Aging of Tire Wear Particles in Anaerobic Flooded Soils: The Role of Iron Reduction and Environmentally Persistent Free Radicals.

Rapid urbanization drives increased emission of tire wear particles (TWPs) and the contamination of a transformation product derived from tire antioxidant, termed as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q), with adverse implications for terrestrial ecosystems and human health. However, whether and how 6PPD-Q could be formed during the aging of TWPs in soils remains poorly understood. Here, we examine the accumulation and formation mechanisms of 6PPD-Q during the aging of TWPs in soils. Our results showed that biodegradation predominated the fate of 6PPD-Q in soils, whereas anaerobic flooded conditions were conducive to the 6PPD-Q formation and thus resulted in a ∼3.8-fold higher accumulation of 6PPD-Q in flooded soils than wet soils after aging of 60 days. The 6PPD-Q formation in flooded soils was enhanced by Fe reduction-coupled 6PPD oxidation in the first 30 days, while the transformation of TWP-harbored environmentally persistent free radicals (EPFRs) to superoxide radicals (O2•-) under anaerobic flooded conditions further dominated the formation of 6PPD-Q in the next 30 days. This study provides significant insight into understanding the aging behavior of TWPs and highlights an urgent need to assess the ecological risk of 6PPD-Q in soils.

Multiple Effects of Humic Components on Microbially Mediated Iron Redox Processes and Production of Hydroxyl Radicals.

Microbially mediated iron redox processes are of great significance in the biogeochemical cycles of elements, which are often coupled with soil organic matter (SOM) in the environment. Although the influences of SOM fractions on individual reduction or oxidation processes have been studied extensively, a comprehensive understanding is still lacking. Here, using ferrihydrite, Shewanella oneidensis MR-1, and operationally defined SOM components including fulvic acid (FA), humic acid (HA), and humin (HM) extracted from black soil and peat, we explored the SOM-mediated microbial iron reduction and hydroxyl radical (•OH) production processes. The results showed that the addition of SOM inhibited the transformation of ferrihydrite to highly crystalline iron oxides. Although FA and HA increased Fe(II) production over four times on average due to complexation and their high electron exchange capacities, HA inhibited 30-43% of the •OH yield, while FA had no significant influence on it. Superoxide (O2•-) was the predominant intermediate in •OH production in the FA-containing system, while one- and two-electron transfer processes were concurrent in HA- and HM-containing systems. These findings provide deep insights into the multiple mechanisms of SOM in regulating microbially mediated iron redox processes and •OH production.

A Novel Strategy to Evaluate the Aromaticity Degree of Natural Organic Matter Based on Oxidization-Induced Chemiluminescence.

Due to its complex composition and structure, many of the properties of natural organic matter (NOM) are poorly understood. In this study, the oxidization-induced chemiluminescence (OCL) of NOM was investigated, and a flow-injection OCL method was developed using alkaline persulfate-H2O2 as the oxidizing agent. The method is suitable for the direct analysis of NOM in both homogeneous and heterogeneous samples without isolation or concentration. A strong linear relationship (p < 0.001) was found between the normalized organic carbon OCL (OCLOC) and the percentage of aromatic carbon in standard NOM and soil samples, suggesting that OCLOC can be used as an empirical indicator to assess the aromaticity degree of NOM in both homogeneous and heterogeneous samples. By using this method, the percentages of aromatic carbon in a forest soil profile with low organic carbon content were estimated, and a decrease in the degree of aromaticity in deeper soil was observed. Considering the high sensitivity (lower than 0.1 mg C L-1) and throughput (13 s per detection) and low sample consumption (less than 1 mg) of the method, the proposed OCLOC indicator shows great promise for the high-throughput evaluation of the aromaticity degree of NOM for a wide variety of environmental and geochemical samples.

Pathway for the Production of Hydroxyl Radicals during the Microbially Mediated Redox Transformation of Iron (Oxyhydr)oxides.

The reduction of ferric iron (Fe(III)) to ferrous iron (Fe(II)) by dissimilatory iron-reducing bacteria is widespread in anaerobic environments. The oxidation of Fe(II) in aerobic environments has been found to produce hydroxyl radicals (•OH); however, the role of iron-reducing bacteria in the process has not been well understood. Here, Shewanella oneidensis MR-1-mediated redox transformation of four typical iron (oxyhydr)oxides and the production of reactive oxygen species were investigated. The results showed that the production of •OH was mainly determined by the insoluble Fe(II) formed during microbially mediated reduction and also mediated by the mineralogical phase. Moreover, this study for the first time observed the exogenetic iron-independent production of •OH by S. oneidensis MR-1, and the integrated pathway of •OH generation during the iron redox process was revealed. Superoxide (O2•-) was indicated as a key intermediate species that was produced by both abiotic and biotic pathways, and •OH was generated by both the exogenetic iron-dependent Fenton-like reaction and exogenetic iron-independent pathways. S. oneidensis MR-1 played a pivotal role in both the reduction of Fe(III) and the production of O2•-. These findings contribute substantially to our understanding of the generation mechanism of reactive oxygen species at oxidation-reduction boundaries in the environment.

Facet-Mediated Adsorption and Molecular Fractionation of Humic Substances on Hematite Surfaces.

Interactions between dissolved organic matter (DOM) and iron oxyhydroxides have important environmental and geochemical implications. The present study employed two hematite nanocrystals to investigate the adsorption and molecular fractionation of two typical humic substances (HSs) using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). Hematite with a predominant exposure of {100} facets induced more pronounced adsorption and molecular fractionation of HSs than {001} facets, indicating that the interfacial adsorptive fractionation process of HSs was mediated by exposed facets of hematite. Further exploration of the surface OH groups of the two hematite nanocrystals confirms that the facet-mediated molecular fractionation of HSs was attributable to the abundance of singly iron-atom coordinated -OH sites on the hematite surfaces. Molecules with a high oxidation state and high aromaticity such as oxidized black carbon, polyphenol-like, and tannic-like compounds preferentially formed ligand-exchange complexes with singly coordinated -OH groups on the hematite surfaces, inducing the selective binding and molecular fractionation of HSs at the mineral-water interface. These results demonstrate that singly iron-atom coordinated -OH sites determine DOM adsorption and mediate molecular fractionation on hematite surfaces, and this contributes substantially to our understanding of the molecular mechanisms of iron oxyhydroxide-mediated molecular exchange of DOM in soils and/or sediments.

Uptake, Translocation, and Biotransformation of Organophosphorus Esters in Wheat (Triticum aestivum L.).

The uptake, translocation and biotransformation of organophosphate esters (OPEs) by wheat (Triticum aestivum L.) were investigated by a hydroponic experiment. The results demonstrated that OPEs with higher hydrophobicity were more easily taken up by roots, and OPEs with lower hydrophobicity were more liable to be translocated acropetally. A total of 43 metabolites including dealkylated, oxidatively dechlorinated, hydroxylated, methoxylated, and glutathione-, and glucuronide- conjugated products were detected derived from eight OPEs, with diesters formed by direct dealkylation from the parent triesters as the major products, followed with hydroxylated triesters. Molecular interactions of OPEs with plant biomacromolecules were further characterized by homology modeling combined with molecular docking. OPEs with higher hydrophobicity were more liable to bind with TaLTP1.1, the most important wheat nonspecific lipid transfer protein, consistent with the experimental observation that OPEs with higher hydrophobicity were more easily taken up by wheat roots. Characterization of molecular interactions between OPEs and wheat enzymes suggested that OPEs were selectively bound to TaGST4-4 and CYP71C6v1 with different binding affinities, which determined their abilities to be metabolized and form metabolite products in wheat. This study provides both experimental and theoretical evidence for the uptake, accumulation and biotransformation of OPEs in plants.

Soil source, not the degree of urbanization determines soil physicochemical properties and bacterial composition in Ningbo urban green spaces.

Urban green spaces provide multiple ecosystem services and have great influences on human health. However, the compositions and properties of urban soil are not well understood yet. In this study, soil samples were collected from 45 parks in Ningbo to investigate the relationships among soil physicochemical properties, heavy metals and bacterial communities. The results showed that soil dissolved organic matter (DOM) was of high molecular weight, high aromaticity, and low degree of humification. The contents of heavy metals were all below the China's national standard safety limit (GB 3660-2018). The bioavailability of heavy metals highly correlated with soil pH, the content of DOC, the fluorescent component, the degree of humification and the source of DOM. The most abundant genera were Gemmatimonadaceae_uncultured, Xanthobacteraceae_uncultured, and Acidothermus in all samples, which were related to nitrogen cycle and bioavailability of heavy metals. Soil pH, bioavailability of Zn, Cd, and Pb (CaCl2 extracted) were the main edaphic factors influencing bacterial community composition. It should be noted that there was no significant impact of urbanization on soil physicochemical properties and bacterial composition, but they were determined by the source of soil in urban green spaces. However, with the passage of time, the effect of urbanization on urban green spaces cannot be ignored. Overall, this study provided new insight for understanding the linkage among soil physicochemical properties, heavy metals, and bacterial communities in urban green spaces.

Aboveground plants determine the exchange of pathogens within air-phyllosphere-soil continuum in urban greenspaces.

The microbiome in the air-phyllosphere-soil continuum of urban greenspaces plays a crucial role in re-connecting urban populations with biodiverse environmental microbiomes. However, little is known about whether plant type affects the airborne microbiomes, as well as the extent to which soil and phyllosphere microbiomes contribute to airborne microbiomes. Here we collected soil, phyllosphere and airborne microbes with different plant types (broadleaf tree, conifer tree, and grass) in urban parks. Despite the significant impacts of plant type on soil and phyllosphere microbiomes, plant type had no obvious effects on the diversity of airborne microbes but shaped airborne bacterial composition in urban greenspaces. Soil and phyllosphere microbiomes had a higher contribution to airborne bacteria in broadleaf trees (37.56%) compared to conifer trees (9.51%) and grasses (14.29%). Grass areas in urban greenspaces exhibited a greater proportion of potential pathogens compared to the tree areas. The abundance of bacterial pathogens in phyllosphere was significantly higher in grasses compared to broadleaf and conifer trees. Together, our study provides novel insights into the microbiome patterns in air-phyllosphere-soil continuum, highlighting the potential significance of reducing the proportion of extensively human-intervened grass areas in future urban environment designs to enhance the provision of ecosystem services in urban greenspaces.

More Talk, More Support? The Effects of Social Network Interaction and Social Network Evaluation on Social Support via Social Media.

Introduction: Do more friends and more frequent interactions on social media result in more social support? The impact of variables such as interaction size and frequency on the social support individuals receive via social platforms has been studied from the perspective of social networks, and some studies have focused on the role of interaction topics from the perspective of private engagement. Little research has been done on the impact of affect control embedded in social networks. The emotion-first nature of social media and the rise of affect control theory mean that this perspective deserves attention. Methods: This study examined 634 WeChat users by means of an online survey on variables related to social media use, such as social network size, interaction frequency, users' evaluation of network members, and personal topic involvement, and then tested the influencing mode of these variables on people's perceived social support through chain mediation analysis using Model 80 of the process in spss. Results: (1) Interaction size influences perceived social support by affecting personal topic involvement; (2) Interaction frequency does not directly mediate the relationship between interaction size and perceived social support, but mediates the relationship in a chain by affecting personal topic involvement; and (3) Social network evaluation not only directly mediates the relationship between interaction size and perceived social support, but also further mediates the relationship by influencing personal topic involvement. Conclusion: The study confirmed the role of affective control in people's perceived social support through social network interactions. Those people talk about personal matters with individuals who have greater evaluation, potency, and activity in social networks are more likely to get perceived social support. The study draws our attention to the role of affection control in interpersonal relationships in the era of social media mediating people's daily interactions.

The impact of culture perception on kinship disconnection of Chinese youth: examining the chain mediating effect of kinship support, kinship burnout, and social media interaction.

Kinship connections are an essential foundation of social relationships in China, yet in recent years there has been an increasing tendency toward kinship disconnection (Duanqin) among Chinese youth. In this study, based on online survey data of 555 Chinese individuals aged 18-35 years under a comprehensive explanatory framework of culturalism, functionalism, and behaviorism, regression and mediation analyses found that (1) cultural perception based on family-state values is the dominant factor influencing people's tendency to disconnect. (2) Kinship support decreases people's propensity to break off relatives, while kinship burnout increases people's propensity to cut off relatives. Both act as functionalist factors in the chain that mediates the effect of cultural perception on the propensity to break kinship, and kinship burnout obscures the effect of kinship support and becomes a differentiating variable. (3) Both social media kin interaction size and kin group activity significantly reduce people's propensity to disconnect. However, group activities are more significant in cultural perception's mediating effect on disconnection propensity. It indicates that truly "active" social media connections are more important. The study attempts to propose a framework of "cultural perception + functional satisfaction and burnout + social media" to interpret Chinese youth kinship communication activity. On a practical level, more support for young people in social media interactions could slow or even reverse the trend of disconnection.

A combined strategy to mitigate the accumulation of arsenic and cadmium in rice (Oryza sativa L.).

Arsenic and cadmium in rice grain are of growing concern in the global food supply chain. Paradoxically, the two elements have contrasting behaviors in soils, making it difficult to develop a strategy that can concurrently reduce their uptake and accumulation by rice plant. This study examined the combined impacts of watering (irrigation) schemes, different fertilizers and microbial populations on the bioaccumulation of arsenic and cadmium by rice as well as on rice grain yield. Compared to drain-flood and flood-drain treatments, continuously flooded condition significantly reduced the accumulation of cadmium in rice plant but the level of arsenic in rice grain remained above 0.2 mg/kg, which exceeded the China national food safety standard. Application of different fertilizers under continuously flooded condition showed that compared to inorganic fertilizer and biochar, manure addition effectively reduced the accumulation of arsenic over three to four times in rice grain and both elements were below the food safety standard (0.2 mg/kg) while significantly increasing the rice yield. Soil Eh was the critical factor in the bioavailability of cadmium, while the behavior of arsenic in rhizosphere was associated with the iron cycle. The results of the multi-parametric experiments can be used as a roadmap for low-cost and in-situ approach for producing safe rice without compromising the yield.

Application of earthworm and silicon can alleviate antibiotic resistance in soil-Chinese cabbage system with ARGs contamination.

Organic fertilization is a major contributor to the spread of antibiotic resistance genes (ARGs) in the agroecosystem, which substantially increases the risk of ARGs acquisition and their transmission into human food chains. Earthworms are among the most vital soil faunas involved in the link between belowground and aboveground, and silicon is beneficial for soil health and plant stress resistance. This study aims to explore the effect of different amendment strategies (earthworm and/or silicon) and the related influencing factors on the alleviation of ARGs using high-throughput qPCR. The results showed that the application of earthworms and silicon fertilizers reduced the absolute abundance of ARGs in the rhizosphere soils, either singly or in combination. According to the structural equation model and random forest analysis, mobile genetic elements are the major factors enhancing ARGs transfers and the treatment affects ARGs in direct or indirect ways. Our results highlight the role of "rhizosphere effect" in alleviating antibiotic resistance and suggest that silicon fertilizers, together with the earthworms, can be considered as a sustainable and natural solution to mitigate high-risk ARGs spread in the soil-plant systems. Our findings provide guidance in formulating strategies for halting the spread of ARGs in the agroecosystem.

Optical properties of sedimentary dissolved organic matter in intertidal zones along the coast of China: Influence of anthropogenic activities.

The intertidal zone, due to its location in the transition zone of terrestrial and marine ecosystems, is seriously disturbed by anthropogenic activities such as fuel combustion and industrial production, causing significant increase in dissolved organic matter (DOM). However, the distribution and properties of DOM in intertidal sediments at the large scale and their correlations with local socio-economic indicators remain unclear. In this study, we collected sediment samples from 13 intertidal zones across 11 coastal provinces in China and analyzed optical properties and compositions of sedimentary DOM. The results showed that the physico-chemical properties of sediment, such as pH and texture, affected the content of organic matter, thereby influencing the concentration of sedimentary DOM indirectly. The contents of fulvic acid- and protein-like components were relatively higher than humic acid-like component at all sampling sites. Moreover, urbanization could lead to the release of aromatic and humified organic matters into intertidal zones. Unlike coal, oil consumption exhibited positive correlation with SUVA254, indicating that the combustion of oil released more aromatic compounds. These findings revealed the impact of anthropogenic activities on sedimentary DOM and provided theoretical basis for predicting and regulating intertidal carbon sink.

How Social Media Influences Public Attitudes to COVID-19 Governance Policy: An Analysis Based on Cognitive-Affective Model.

Introduction: Based on the cognitive-affective model, this paper examines how social media affects the public cognitive and affective factors, further influence their attitudes towards COVID-19 governance policy. Methods: Through an online survey, we measured individual COVID-19 policy attitude, social media use and other related factors of 1222 respondents from 12 countries, and based on this, we carried out regression and mediation analysis on the data to obtain the research results. Results: From the perspective of cognitive factors, the public perception of the severity of the COVID-19 itself does not significantly affect their attitudes towards governance policy. On the contrary, the evaluation on government governance performance, risks and governance anticipations have more significant impacts. Among the affective factors, personal anxiety and patriotism significantly affect the formation of public attitudes, personal anxiety is positively correlated, and patriotism is negatively correlated. It is important to note that nationalism has no significant influence on public attitudes to COVID-19 policy on a global scale. Conclusion: (1) Social media influences the public COVID-19 policy attitudes through their moderating effect on affective and cognitive factors. (2) The impact of social media on affective pathways is more significant than that on cognitive pathways. (3) The positive moderating effect of social media on patriotism obscures the tendency of strict governance of COVID-19 caused by aggravating people's anxiety.

How Media Exposure, Media Trust, and Media Bias Perception Influence Public Evaluation of COVID-19 Pandemic in International Metropolises.

International metropolises are key sites of outbreaks of COVID-19 cases. Global public evaluation of the pandemic in international cities is affected by many factors. This study examines how media exposure affects this evaluation and how media trust and media bias perception moderate the relationship between them. Based on an online survey of the evaluation of 13 international cities' pandemic performances by 1171 citizens from 11 countries, this study conducted a multi-level stepwise regression analysis and discovered that: (1) different forms of media affect global citizens' perceptions of international metropolis COVID-19 pandemic performance differently; and the role of traditional paper media, including newspapers and magazines, is of little significance in comparison to electronic media. (2) Among electronic media, TV and broadcasting have the greatest impact, followed by social media and the Internet. (3) Media trust and media bias perception affect people's evaluations of international urban pandemics, but our survey reveals that they only function with regard to social media.

Correlative distribution of DOM and heavy metals in the soils of the Zhangxi watershed in Ningbo city, East of China.

In peri-urban critical zones, soil ecosystems are highly affected by increasing urbanization, causing probably an intense interaction between dissolved organic matter (DOM) and heavy metals in soil. Such interaction is critical for understanding the biogeochemical cycles of both organic matter and heavy metals in these zones. However, limited research has reported the correlative distribution of DOM and heavy metals at high seasonal and spatial resolutions in peri-urban critical zones. In this study, 160 soil samples were collected from the farmland and forestland of Zhangxi watershed, in Ningbo, eastern China during spring, summer, fall and winter four seasons. UV-visible absorption and fluorescent spectroscopy were used to explore the optical characteristics of DOM. The results indicated a mixture of exogenous and autogenous sources of DOM in the Zhangxi watershed, while DOM in farmland exhibited a higher degree of aromaticity and humification than that in forestland. Fluorescent results showed that humic acid-like, fulvic acid-like and microbial-derived humic-like fractions were mostly affected by seasons. The distribution of heavy metals was affected mainly by land-use changes and seasons. Correlation analysis between heavy metals and DOM characteristics and components suggested that aromatic and humic substances were more favorable in binding with EDTA extractable Ni, Cu, Zn and Cd. The bioavailable Cd and Pb decreased due to binding with humic fractions, indicating its great effects on the bioavailability of Cd and Pb. Overall, these findings provide an insight into the correlative distributions of DOM and heavy metals in peri-urban areas, thereby highlighting their biogeochemical cycling in the soil environment.

The Impact of Pandemic Perception, National Feeling, and Media Use on the Evaluation of the Performance of Different Countries in Controlling COVID-19 by Chinese Residents.

Different nations responded to the global spread of COVID-19 differently. How do people view the governance practices and effects of various countries? What factors affect their views? Starting from the three-dimensional model of cognitive-affective-media, this study examines how pandemic perception, the national feeling, which is the emotional preference of public for different countries, and media use affect the Chinese public views on the performance of other countries in controlling COVID-19. After performing regression analysis on the data of 619 Chinese public samples collected by an online survey, it reveals the following: (1) pandemic perception is negatively correlated with the evaluation of controlling-pandemic performance in different countries by Chinese residents, whereas national feeling is positively correlated with the evaluation of controlling-pandemic performance. (2) The use of media has different characteristics in the evaluation of controlling-pandemic performance in different countries by Chinese residents. Television has a significant influence on the evaluation of controlling-pandemic performance in the United States, China, and Germany by Chinese residents. (3) Collectivist cultural orientation has no significant impact on the evaluation of the anti-pandemic performance of different countries by Chinese residents, whereas virus perception only has a significant impact on the evaluation of the controlling-pandemic performance of the United States and Italy. Research has confirmed the existence of the cognitive-affective-media model in the evaluations by public on the governance of other countries, and prospects for the superimposed role of media in the cognitive-affective model.

Hematite facet-mediated microbial dissimilatory iron reduction and production of reactive oxygen species during aerobic oxidation.

Microbial dissimilatory iron reduction and aerobic oxidation affect the biogeochemical cycles of many elements. Although the processes have been widely studied, the underlying mechanisms, and especially how the surface structures of iron oxides affect these redox processes, are poorly understood. Therefore, {001} facet-dominated hematite nanoplates (HNP) and {100} facet-dominated hematite nanorods (HNR) were used to explore the effects of surface structure on the microbial dissimilatory iron reduction and aerobic oxidation processes. During the reduction stage, the production of total Fe(II) normalized by specific surface area (SSA) was higher for HNP than HNR due to steric effects and the ligand-bound conformation of the connection between iron on different exposed facets and electron donors from microorganisms. However, during the aerobic oxidation stage, both the SSA- and Fe(II)-normalized reactive oxygen species (ROS), including hydrogen peroxide (H2O2) and hydroxyl radical (•OH), were higher for HNR than HNP. Theoretical calculation results showed that the {100} facets exhibited a lower activation energy barrier for oxygen reduction reaction than {001} facets, supporting the experimental observation that {100} facet-dominated HNR had a higher ROS production efficiency than {001} facet-dominated HNP. These results indicated that surface characteristics not only mediated the microbial reduction of Fe(III) but also affected the aerobic oxidation of microbially reduced Fe(II). Accessibility of electron donors to surface iron atom determined the reduction of Fe(III), and activation energy barrier for oxygen reduction by surface Fe(II) dominated the ROS production during the redox processes. This study advances our understanding of the mechanisms through which ROS are produced by iron (oxyhydr)oxides during microbial dissimilatory iron reduction and aerobic oxidation processes.

Sustained production of superoxide radicals by manganese oxides under ambient dark conditions.

Manganese (Mn) oxides are ubiquitous in the environment and have strong reactivity to induce the transformation of various contaminants. However, whether reactive oxygen species contribute to their surface reactivity remains unclear. Here, sustainable production of superoxide radicals (O2•-) by various MnO2 polymorphs in the dark was quantified and the mechanisms involved were explored. The results confirm that O2•- was produced through one-electron transfer from surface Mn(III) to adsorbed O2. In contrast, no H2O2 was detected due to its decomposition by Mn oxides to form O2•- and Mn(III), leading to the sustained production of O2•- on Mn oxide surfaces. In addition, the production of O2•- was found to make a clear contribution (4 - 28%) to the transformation of a series of halophenols by MnO2, suggesting that the O2•--mediated surface reaction is an important supplement to the direct electron-transfer mechanism in the reactivity of Mn oxides. These findings advance our understanding of the surface reactivity of Mn oxides and also reveal an important but hitherto unrecognized abiotic source of O2•- in the natural environment.