Ambient particulate pollution, especially PM₂.₅, has adverse impacts on health and welfare. To manage and control PM₂.₅ pollution, it is of great importance to determine the factors that affect PM₂.₅ levels. Previous studies commonly focused on a single or several cities. This study aims to analyze the impacts of meteorological and socio-economic factors on daily concentrations of PM₂.₅ in 109 Chinese cities from January 1, 2015 to December 31, 2015.To evaluate potential risk factors associated with the spatial and temporal variations in PM₂.₅ levels, we developed a Bayesian spatio-temporal model in which the potential temporal autocorrelation and spatial autocorrelation of PM₂.₅ levels were taken into account to ensure the independence of the error term of the model and hence the robustness of the estimated parameters.Daily concentrations of PM₂.₅ peaked in winter and troughed in summer. The annual average concentration reached its highest value (79 μg/m³) in the Beijing-Tianjin-Hebei area. The city-level PM₂.₅ was positively associated with the proportion of the secondary industry, the total consumption of liquefied petroleum gas and the total emissions of industrial sulfur dioxide (SO₂), but negatively associated with the proportion of the primary industry. A reverse U-shaped relationship between population density and PM₂.₅ was found. The city-level and daily-level of weather conditions within a city were both associated with PM₂.₅.PM₂.₅ levels had significant spatio-temporal variations which were associated with socioeconomic and meteorological factors. Particularly, economic structure was a determinant factor of PM₂.₅ pollution rather than per capita GDP. This finding will be helpful for the intervention planning of particulate pollution control when considering the environmental and social-economic factors as part of the strategies.

Methyl tert-butyl ether (MTBE) degradation technologies based on two-phase partitioning systems such as extractive membrane biofilm reactors (EMBFR) permit separation of biological and contaminant compartments, thus allowing optimization of the biological section. In this study, we set-up an EMBFR with three MTBE-degrading and cooperating strains (termed social biofilm: Agrobacterium sp. MS2, Paenibacillus etheri SH7ᵀ and Rhodococcus ruber EE6). The removal efficiency of the social-biofilm EMBFR was 80%, and functional stability was observed in the reactor, i.e. more efficient than previous studies (single-strain inoculated EMBFR, <50% removal efficiency and unstable function). Metabolite tert-butyl alcohol was not observed, and the EC₅₀ values were higher than those observed in single-strain EMBFRs. Comparative analysis of the MTBE enzymatic pathway and the social-biofilm was performed, where the mechanism of cooperation observed within the social-biofilm is likely due to enzymatic redundancy. Functional outcomes were equal to previous batch tests, hence 100% scalability was obtained. Overall, higher functional and stability outcomes are obtained with the use of the social-biofilm in an MTBE-EMBFR.

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths in the study area. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na+, K+, Cl−, SO42−, PO43− and NO3−. The groundwater samples collected from shallow water sources were observed to contain higher amount of dissolved salts. EC, TA, Cl−, TH, Na+, and K+ were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste,dumping of industrial waste and agricultural activities, in the nearby areas, could lead to deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality so as to minimize public health risks.

Parent polycyclic aromatic hydrocarbons (PPAHs) in the ambient air of the coastal cities near the Bohai and Yellow Seas were measured over a full year. The range and geometric average of total PPAH₂₉ (29 species) were 5.16-1.22 × 10³ and 118 ng/m³, respectively, with 77 ± 14% in a gaseous phase. The 16 priority components accounted for 90 ± 4% of the total mass concentration. The incremental life cancer risk (ILCR) via inhalation exposure to the PPAHs (3.17 × 10⁻⁴) was underestimated by 80%, as only the priority PPAHs were considered. The air concentrations of PPAHs in the Bohai Sea area were generally higher (p < 0.01) than those in the Yellow Sea area. A significant increase (p < 0.01) in the levels of PPAHs and large fractions of high molecular weight (HMW) components were observed in winter. Absorption by particulate organic carbon dominated in gas-particle partitioning of the PPAHs, and the seasonal variations in gas-particle partitioning of the low and moderate molecular weight compounds were more noticeable relative to the HMW species. In summer, significantly higher concentrations of PPAHs were found in the daytime than during nighttime, while the opposite case occurred in winter (p < 0.05). The positive matrix factorization (PMF) results indicated greater contributions of coal and biomass combustion to the PPAH emissions in the coastal cities of the Bohai Sea area compared with the Yellow Sea area. The burning of coal and biomass served as the main source of PPAHs in winter, while traffic exhaust was the dominant source in other seasons. The potential source contribution function (PSCF) revealed the important impacts of the external inputs on the local PPAHs via air mass transport. The contributions of the resolved emission sources to the ILCR were clearly different from those of the mass concentrations, indicating the necessity for source-oriented risk assessments.

Pyrazole derivatives display diverse biological and pharmacological activities. The aim of this study is to investigate the antioxidant properties of a novel pyrazolecarboxamide derivative (4-amino-N-[(4-chlorophenyl)]-3-methyl-1-phenyl-1H-thieno [2, 3-c] pyrazole-5-carboxamide) in African catfish, Clarias gariepinus, exposed to 1 mg/L PbNO₃. Fish were intramuscularly injected with pyrazole-5-carboxamidederivative according to the following groupings: Group 1 (control), Group 2 (1 mg/L lead nitrate), Group 3 (1 mg/L lead nitrate + 5 mg pyrazole derivative/kg body weight), and Group 4 (1 mg/L lead nitrate + 10 mg pyrazole derivative/kg body weight) for two weeks and four weeks. Lead nitrate (1 mg/L) caused significant elevation of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, uric acid, cholesterol, and glucose-6-phosphate dehydrogenase (G6PDH) compared to the control group after two and four weeks of exposure, while serum total lipids, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were significantly reduced compared to the control group. Furthermore, levels of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and total antioxidant capacity (TAC) were reduced in group 2 compared to the control group. However, in group 2, hepatic lipid peroxidation (LPO) and DNA fragmentation percentage were significantly increased compared to the control group. Histopathological changes in the liver of lead-exposed groups included marked disturbance of hepatic tissue organization, degeneration of hepatocytes, dilation of blood sinusoids and the central vein as well as necrosis. Injection of pyrazole derivative for two weeks and four weeks reversed alterations in biochemical parameters, antioxidant biomarkers, lipid peroxidation, hepatic DNA damage, and histopathological changes in liver tissue induced by 1 mg/L lead nitrate. This amelioration was higher in response to high-dose pyrazole derivative (10 mg) at the fourth week of exposure, showing concentration-and time-dependency. Overall, the sensitized derivative pyrazolecarboxamide is likely a useful tool to minimize the effects of lead toxicity due to its potent antioxidant activity.

The binding of metal ions with humic acid (HA) plays an important role in the aggregation of HA and the migration of metal ions in the environments. The effects of common cations (Na⁺, Mg²⁺, Ca²⁺ and Al³⁺) and heavy metal ions (Ag⁺, Cd²⁺, Cu²⁺, Cr³⁺ and Eu³⁺) on the aggregation of HA were investigated systematically by aggregation kinetics, spectroscopic techniques and molecular dynamic (MD) simulations. The critical coagulation concentration (CCC) of mono-, di- and trivalent cations could be predicted by the Schulze-Hardy rule. The aggregation of HA in the presence of Na⁺ and Ag⁺ was mainly due to the reduction of repulsive force and the hydrogen bonds between HA molecules. While the complexation of di- and trivalent cations with carboxylic/phenolic groups, or the cation-π interactions enhanced the intra- or inter-molecular bridges in HA and then contributed greatly to the aggregation of HA. Heavy metal ions could easily pass through the electric double-layer of HA compared with common cations. MD simulations further signified the strong aggregation ability of HA molecules in solutions containing high valence metal ions. These findings are important for understanding not only how the influence of metal ions on the aggregation of HA, but also the conditions which ions more efficient for aggregation.

Chronic ambient fine particulate matter (PM₂.₅) exposure correlates with various adverse health outcomes. Its impact on the circulating metabolome−a comprehensive functional readout of the interaction between an organism's genome and environment−has not however been fully understood. This study thus performed metabolomics analyses using a chronic PM₂.₅ exposure mouse model. C57Bl/6J mice (female) were subjected to inhalational concentrated ambient PM₂.₅ (CAP) or filtered air (FA) exposure for 10 months. Their sera were then analyzed by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). These analyses identified 2570 metabolites in total, and 148 of them were significantly different between FA- and CAP-exposed mice. The orthogonal partial least-squares discriminant analysis (OPLS-DA) and heatmap analyses displayed evident clustering of FA- and CAP-exposed samples. Pathway analyses identified 6 perturbed metabolic pathways related to amino acid metabolism. In contrast, biological characterization revealed that 71 differential metabolites were related to lipid metabolism. Furthermore, our results showed that CAP exposure increased stress hormone metabolites, 18-oxocortisol and 5a-tetrahydrocortisol, and altered the levels of circadian rhythm biomarkers including melatonin, retinal and 5-methoxytryptophol.

Previous studies have linked ambient PM₂.₅ to decreased pulmonary function, but the influence of specific chemical elements and emission sources on the severe asthmatic is not well understood. We examined the mass, chemical constituents, and sources of PM₂.₅ for short-term associations with the pulmonary function of adults with severe asthma in a low air pollution environment in urban Nagasaki, Japan. We recruited 35 asthmatic adults and obtained the daily record of morning peak expiratory flow (PEF) in spring 2014–2016. PM₂.₅ filters were extracted from an air quality monitoring station (178 days) and measured for 27 chemical elements. Source apportionment was performed using Positive Matrix Factorization (PMF). We fitted generalized linear model with generalized estimating equation (GEE) method to estimate changes in PEF (from personal monthly maximum) and odds of severe respiratory deterioration (first ≥ 15% PEF reduction within a 1-week interval) associated with mass, constituents, and sources of PM₂.₅, with adjustment for temperature and relative humidity. Constituent sulfate (SO₄²⁻) and PM₂.₅ from oil combustion and traffic were associated with reduced PEF. An interquartile range (IQR) increase in SO₄²⁻ (3.7 μg/m³, average lags 0–1) was associated with a decrease of 0.38% (95% confidence interval = −0.75% to −0.001%). An IQR increase in oil combustion and traffic-sourced PM₂.₅ (2.64 μg/m³, lag 1) was associated with a decrease of 0.33% (−0.62% to −0.002%). We found a larger PEF decrease associated with PM₂.₅ from dust/soil on Asian Dust days. There was no evidence linking total mass and metals to reduced pulmonary function. The ventilatory capacity of adults with severe asthma is susceptible to specific constituents/sources of PM₂.₅ such as sulfate and oil combustion and traffic despite active self-management of asthma and low air pollution levels in the study location.

Inductively coupled plasma – mass spectrometry (ICP-MS) analysis of airborne particulate bound mercury was carried out utilizing a high sulfur containing organic compound as a preservation agent to limit the negative bias that affects the determination of low levels of mercury. Between 600% and 1000% more Hg was detected with the use of the additive, lithium tetrathiafulvalene carboxylate (LiCTTF), during the microwave assisted acid digestion sample processing step without influencing the determination of other trace elements. The average Hg concentration was 0.05 ng m⁻³ and 0.4 ng m⁻³ in the absence and presence of LiCTTF, respectively. Stabilization of the mercury ions with the preservation agent resulted in higher precision for ICP-MS measurements with relative standard deviation (RSD) values ranging from 1.07% to 4.36%. The results obtained in this study emphasize the necessity of using a preservation agent in the atomic spectroscopic determination of mercury to prevent losses and is especially critical in low-level analyses such as those routinely performed in environmental mercury pollution trend assessments.

The ecological impacts of insecticides in aquatic areas around agricultural lands have long been ignored in the regulation scheme of pesticides in Japan. Upon the scheme, the predicted concentration of an insecticide in the main stream of a river is the only parameter considered, suggesting that the ecological impacts of insecticides on local biodiversity around agricultural fields are underestimated. To fill this knowledge gap, we measured insecticide concentrations in surface water and sediment in aquatic areas around paddy fields at 35 locations across Japan. Among the 18 insecticides considered, 15 were detected somewhere in Japan and their concentrations were generally higher in the southwestern region in Japan (e.g. Hiroshima, Saga, or Kagoshima prefectures). Most insecticides were accumulated at higher concentrations in sediment than in surface water, consistent with previous studies. We also detected insecticides applied to nursery boxes at high concentrations in surrounding aquatic areas, although such application is generally considered to have low environmental risks. In addition, derivatives of fipronil, which have similar toxicity as that of fipronil, were often detected in sediment at higher concentrations than fipronil itself. Concentrations of dinotefuran in water at two sampling points were higher than the 5% hazardous concentration (HC5), indicating a possibility of a risk of acute toxicity to aquatic organisms. Our findings indicate that ecological risk assessments of insecticides and their derivatives should be expanded to include concentrations in sediment and water around paddy fields as well.