Biochar addition to soil may change the hydrophobicity of amended soil and influence soil hydraulic properties. Soil hydrophobicity, i.e. soil water repellency (SWR) can interrupt water infiltration and form preferential flow leading to a potential risk of soil erosion or groundwater pollution. Up to date, the effect of different biochars on soil hydrophobicity remains unclear and the association of SWR with soil hydraulic properties is still unknown. To link the biochar hydrophobicity to SWR and soil water holding capacity (WHC), the surface structure and chemical composition of 27 biochars with different feedstocks and pyrolysis temperatures were characterized, and the SWR and soil WHC of biochar-added soil were investigated. Carboxylic groups on the biochar surface, surface area and pore volume were mostly influenced by pyrolysis temperature, which suggested the dominant factor determining the severity of biochar hydrophobicity was pyrolysis temperature. Hydrophilic soil became hydrophobic after biochar amendment. A higher addition rate led to a stronger SWR of hydrophilic soil. Biochar addition increased soil WHC of hydrophilic soil with low total organic carbon (TOC) content. Biochar did not have significant influence on SWR and soil WHC of hydrophobic soil with high TOC content. It implied that the influence of biochar on SWR and soil hydraulic properties mainly depended on soil original hydrophobicity and TOC content. Therefore, the properties of biochar and influence on soil hydrophobicity and hydraulic properties should be considered before processing biochar application.

Metabolic syndrome is an important risk factor for non-communicable diseases, particularly type 2 diabetes, coronary heart disease, and stroke. Long-term exposure to greenspace could be protective of metabolic syndrome, but evidence for such an association is lacking. Accordingly, we investigated the association between long-term exposure to greenspace and risk of metabolic syndrome.The present longitudinal study was based on data from four clinical examinations between 1997 and 2013 in 6076 participants of the Whitehall II study, UK (aged 45–69 years at baseline). Long-term exposure to greenspace was assessed by satellite-based indices of greenspace including Normalized Difference Vegetation Index (NDVI) and Vegetation Continuous Field (VCF) averaged across buffers of 500 and 1000 m surrounding the participants’ residential location at each follow-up. The ascertainment of metabolic syndrome was based on the World Health Organization (WHO) definition. Hazard ratios for metabolic syndrome were estimated using Cox proportional hazards regression models, controlling for age, sex, ethnicity, lifestyle factors, and socioeconomic status.Higher residential surrounding greenspace was associated with lower risk of metabolic syndrome. An interquartile range increase in NDVI and VCF in the 500 m buffer was associated with 13% (95% confidence interval (CI): 1%, 23%) and 14% (95% CI: 5%, 22%) lower risk of metabolic syndrome, respectively. Greater exposure to greenspace was also associated with each individual component of metabolic syndrome, including a lower risk of high levels of fasting glucose, large waist circumference, high triglyceride levels, low HDL cholesterol, and hypertension. The association between residential surrounding greenspace and metabolic syndrome may have been mediated by physical activity and exposure to air pollution.The findings of the present study suggest that middle-aged and older adults living in greener neighbourhoods are at lower risk of metabolic syndrome than those living in neighbourhoods with less greenspace.

An emission inventory of carbonyl sulfide (COS) from primary anthropogenic sources in China was compiled from 2010 to 2015. The national total emission was estimated at 174 Gg S yr⁻¹ in 2015, with an annually average sustainable growth rate of 7.2% from 2010 to 2015. Industrial sources, biomass burning, coal combustion, agricultural sources and vehicle exhaust contributed 68.2%, 22.0%, 6.1%, 2.2%, and 1.5%, respectively, of total COS emissions in 2015. Aluminum production, carbon black production, titania production, coke production, pulp and paper industry, were the main industrial sources of COS, with the emission about 118 Gg S yr⁻¹ COS in 2015, accounting for 98.5% of total direct emissions from the Chinese industry. The distribution of COS emissions in China showed significant differences at the provincial level. In Shandong and Xinjiang province, they were much bigger than other provinces, with total emissions of 31 and 15 Gg S yr⁻¹, respectively. Uncertainty analysis of COS emission inventories showed that the emission range was 70–267 Gg S yr⁻¹ at a 95% confidence interval. In this study, COS emissions in China were much higher than prior underestimated estimations, even for Asian and global emissions, which could be resolved part of missing sources in the global COS budget.

Few attempts have been made to systematically investigate the impacts of urbanization on PM₂.₅ concentrations in countries at different stages of economic development. In this study, a broad concept of urbanization that considers the transformations in the urban economy and the transport sector induced by urbanization is proposed to investigate the influence of urbanization on national PM₂.₅ concentrations for underdeveloped, developing and developed countries during 1998–2014. The results indicate that urbanization has a significant relationship with PM₂.₅ concentrations, but the magnitude of its influence varies among groups of countries with different development levels. First, the positive response of PM₂.₅ concentrations to increased urbanization and transport-related emissions in underdeveloped countries are noticeably stronger than that in developing and developed countries. Second, for developing countries, urbanization, transport-related emissions and industrialization all have a significant positive effect on national PM₂.₅ concentrations increase, although their impacts are unexpectedly smaller than those in the other groups of countries. Finally, increasing urbanization and the decrease in CO₂ emissions from manufacturing industry appear to reduce national average PM₂.₅ concentrations in developed countries, while the decrease in transport-related CO₂ emission is likely to cause the rise in national average PM₂.₅ concentrations.

A particulate matter (PM) source apportionment study was carried out in one of the most polluted districts of Tuscany (Italy), close to an old waste incinerator plant. Due to the high PM10 levels, an extensive field campaign was supported by the Regional Government to identify the main PM sources and quantify their contributions. PM10 daily samples were collected for one year and analysed by different techniques to obtain a complete chemical characterisation (elements, ions and carbon fractions). Hourly fine (<2.5 μm) and coarse (2.5–10 μm) aerosol samples were collected by a Streaker sampler for a shorter period and hourly elemental concentrations were obtained by PIXE.Positive Matrix Factorization (PMF) analysis of daily and hourly data allowed the identification of 10 main sources: six anthropogenic (Biomass Burning, Traffic, Secondary Nitrates, Secondary Sulphates, Incinerator, Heavy Oil combustion), two natural (Saharan Dust and Fresh Sea Salt) and two mixed sources (Local Dust and Aged Sea Salt). Biomass burning turned out to be the main source of PM, accounting for 30% of the PM10 mass as annual average, followed by Traffic (18%) and Secondary Nitrates (14%). Emissions from the Incinerator turned out to be only 2% of PM10 mass on average.PM10 composition and source apportionment have been assessed in a polluted area near a waste incinerator, by PMF analysis on daily and hourly compositional data sets.

Phytochelatins (PCs) play a vital role in the tolerance and enrichment of cadmium (Cd) in higher plants by chelating with Cd2+. The aim of this study was to perform a full-scale metabolomics analysis of metabolic responses highly correlated with PCs generation. These metabolites and metabolic pathways were expected to promote PCs generation and further optimize Cd absorption in plants. In the current study, Amaranthus hypochondriacus, a potential species for phytoremediation, was first adopted to investigate physiological responses to Cd stress via LCMS/MS-based metabolomics and the HPLC based determination of thiol compounds. The results showed that the leaves of A. hypochondriacus under high Cd stress accumulated 40 times the amount of Cd compared to the leaves of the plants not under Cd stress and had an increased content of three types of PCs. Metabolomics qualitatively identified 12084 substances in total, among which 41 were significantly different metabolites (SDMs) between the two groups and involved in 7 metabolic pathways. Among the SDMs, 12 metabolites were highly linearly correlated with PCs involved in three pathways (Val, Leu and Ile biosynthesis; Ala, Asp and Glu metabolism; and Arg and Pro metabolism). These results provide an innovative method to promote PCs synthesis for the restoration of Cd-contaminated-soil.

Some basic research has shown that nanomaterials can aggravate allergic asthma. However, its potential mechanism is insufficient. Based on the research that alumina nanopowder (nAl2O3) has been reported to cause lung tissue damage, the purpose of this study was to explore the relationship between nAl2O3 and allergic asthma as well as its molecular mechanism. In this study, Balb/c mice were sensitized with ovalbumin (OVA) to construct the allergic asthma model while intratracheally administered 0.5, 5 or 50 mg kg−1·day−1 nAl2O3 for 3 weeks. It was observed that exposure to nAl2O3 exacerbated airway hyperresponsiveness (AHR), airway remodeling, and inflammation cell infiltration, leading to lung function damage in mice. Results revealed that nAl2O3 could increase ROS levels and decrease GSH levels in lung tissue, promote the increases of the T-IgE, TGF-β, IL-1β and IL-6 levels, stimulate the overexpression of transcription factors GATA-3 and RORγt, decrease the levels of IFN-γ and IL-10 and increase the levels of IL-4 and IL-17A, resulting in the imbalance of Th1/Th2 and Treg/Th17 immune responses. In addition, antioxidant Vitamin E (Vit E) could alleviate asthma-like symptoms through blocking oxidative stress. The study displayed that exposure of nAl2O3 deteriorated allergic asthma through promoting the imbalances of Th1/Th2 and Treg/Th17.

The Athabasca Oil Sands Region (AOSR) in Alberta, Canada, is an important source of atmospheric pollutants, such as aerosols, that have repercussions on both the climate and human health. We show that the mean freezing temperature of snow-borne particles from AOSR was elevated (−7.1 ± 1.8 °C), higher than mineral dust which freezes at ∼ −15 °C and is recognized as one of the most relevant ice nuclei globally. Ice nucleation of nanosized snow samples indicated an elevated freezing ability (−11.6 ± 2.0 °C), which was statistically much higher than snow-borne particles from downtown Montreal. AOSR snow had a higher concentration (∼2 orders of magnitude) of >100 nm particles than Montreal. Triple quadrupole ICP-(QQQ)-MS/MS analysis of AOSR and Montreal snow demonstrated that most concentrations of metals, including those identified as emerging nanoparticulate contaminants, were much more elevated in AOSR in contrast to Montreal: 34.1, 34.1, 16.6, 5.8, 0.3, 0.1, and 9.4 mg/m³ for Cr, Ni, Cu, As, Se, Cd, and Pb respectively, in AOSR and 1.3, 0.3, 2.0, <0.03, 0.1, 0.03, and 1.2 mg/m³ in Montreal snow. High-resolution Scanning Transmission Electron Microscopy/Energy-dispersive X-ray Spectroscopy (STEM-EDS) imaging provided evidence for various anthropogenic nano-materials, including carbon nanotubes resembling structures, in AOSR snow up to 7–25 km away from major oil sands upgrading facilities. In summary, particles characterized as coming from oil sands are more efficient at ice nucleation. We discuss the potential impacts of AOSR emissions on atmospheric and microphysical processes (ice nucleation and precipitation) both locally and regionally.

Solid phase extraction has been increasingly applied for the detection of organic micropollutants (OMPs). However, time-consuming and high-cost disadvantages also limit the widespread use of this method, especially for the extraction of large-volume field water samples. In this study, a gas chromatography-mass spectrometry (GC-MS) method based on the magnetic microsphere (M150) solid-phase-extraction (MSPE) was established to investigate the OMPs in source water throughout the whole Huai River. In brief, the results demonstrated that the extraction efficiency of the M150 was superior to that of C₁₈ and HLB for the selected OMPs, including species of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), phthalate esters (PAEs) and nitrobenzenes (NBs), and the method detection limits of M150 for these OMPs were comparable to those of C₁₈ and HLB. The optimized conditions of extraction and elution were the 100 mg/L dosages of microspheres, extraction time of 60 min and pH of 2, and the eluent with a similar polarity, hydrophobicity and molecular structure to the OMPs rendered higher elution efficiencies. A total of 21 types of OMPs affiliating to PAHs, OCPs, PAEs and NBs were detected by the established method, with the total concentrations of 505–2310 ng/L in source water of the Huai River. Spatial differences of the OMPs were also observed, demonstrating the link between pollutant profiles and geographical locations. This study provides an alternative to enrich OMPs in filed water samples, and it reveals pollutant profiles of source water throughout the whole Huai River.

Sustainable alternatives to landfill disposal for municipal mixed wastes represents a major challenge to governments and waste management industries. In the state of New South Wales (NSW) Australia, mechanical biological treatment (MBT) is being used to reduce the volume and pathogen content of organic matter isolated from municipal waste. The product of this treatment, a compost-like output (CLO) referred to as mixed waste organic output (MWOO), is being recycled and applied as a soil amendment. However, the presence of contaminants in MWOO including trace organics, trace metals and physical contaminants such as microplastic fragments has raised concerns about potential negative effects on soil health and agriculture following land application. Here, we used multiple lines of evidence to examine the effects of land application of MWOO containing microplastics in three soils to a variety of terrestrial biota. Treatments included unamended soil, MWOO-amended soil and MWOO-amended soil into which additional high-density polyethylene (HDPE), polyethylene terephthalate (PET), or polyvinyl chloride (PVC) microplastics were added. Tests were conducted in soil media that had been incubated for 0, 3 or 9 months. Addition of microplastics had no significant negative effect on wheat seedling emergence, wheat biomass production, earthworm growth, mortality or avoidance behaviour and nematode mortality or reproduction compared to controls. There was also little evidence the microplastics affected microbial community diversity, although measurements of microbial community structure were highly variable with no clear trends.