High volume air samples were collected from April 2016 to March 2017 at five locations across the Beijing-Tianjin-Hebei (BTH) region, to investigate the atmospheric occurrence of organophosphate esters (OPEs). The mean atmospheric concentrations of ∑₈OPEs (gas and particle phases) varied from 531 ± 393 pg/m³ to 2180 ± 1490 pg/m³ with the highest level observed at the urban sampling site in Tianjin City. ∑₈OPEs were predominated by the chlorinated OPEs (TCEP, TCPP, and TDCIPP), which accounted for 60% ± 16% of the OPE concentrations across the BTH region. Generally, higher levels of gaseous OPEs were found in summer, while higher levels of particle-bound OPEs were observed in winter. The concentrations of gaseous OPEs were positively and significantly correlated with local temperatures (p < 0.05) and relative humidity (p < 0.01), while significantly positive correlations were found between concentrations of particle-bound OPEs and total suspended particulates (TSP) (p < 0.01). These findings confirmed that temperatures, relative humidity and levels of TSP are the main drivers for OPE distributions in different seasons and areas. Gas/particle partitioning of OPEs was also investigated based on the absorption-partitioning model (octanol–air partitioning coefficient (Kₒₐ) -based model) and Junge–Pankow adsorption-partitioning model (J-P model). Kₒₐ-based model generally showed a better performance in comparison with the measured results. The assessment of inhalation exposure risks indicated that relatively higher exposure risks were found in the urban areas, in particular, in Tianjin City (a median value of the estimated daily intake (EDI) of 106 pg/kg body weight/day), suggesting that more attention should be drawn to OPE distributions in the heavily industrialized megacities.

Understanding the factors that affect spatial differences in PM2.5 composition is crucial for implementing emissions control and health policies. Although previous studies have explored modeling of spatial patterns as a tool to improve human exposure assessment, little work has employed a multivariate clustering approach to identify spatial patterns in particle composition. In this study, we used this approach to assess the spatial patterns of ambient PM2.5 elemental concentrations in Eastern Massachusetts in the United States. To distinguish one cluster of sites from another, we considered air pollution sources and geodemographic variables. We evaluated spatial patterns for 11 elemental components of ambient PM2.5, which included S, K, Ca, Fe, Zn, Cu, Ti, Al, Pb, V, and Ni. The analyses for S, Ca, Cu, Ti, Al, and Pb resulted in: 2 clusters for Fe, Zn, V, and Ni; 3 clusters; and for 12 clusters for K. Overall, our findings suggest substantial variation of clusters among PM2.5 components. In addition, land use, population density, and daily traffic were used as variables to more effectively characterize clusters of sites. We used R2 values to estimate the effectiveness of each variable in characterizing clusters. Larger R2 values indicate better the discrimination among the sites. For example, population density had the highest R2 value when the analysis was performed for S, Ca, Zn, Ti, Al, Pb, and V; land use presented the highest R2 value for Cu, V, and Ni; and, traffic showed the highest R2 value for PM2.5 mass concentration. This study improves the ability to model both the between- and within-area variability of source emissions and pollution regime, using concentrations of PM2.5 components.

The present study evaluated the river water quality improvement by implementation of household-based biodigesters in vulnerability and poverty rural area, in Minas Gerais State-Brazil. For that, 78 household-based biodigesters were installed for domestic wastewater treatment. Wastewater was collected before and after treatment and the physicochemical parameters and pathogens removal (human adenovirus (HAdV), hepatitis A (HAV) virus, Salmonella sp. and Escherichia coli) were evaluated; Additionally, river water was sampled before and after the household-based biodigesters implementation, to verify the contamination reduction and the positive impact of domestic wastewater treatment on waterborne pathogen reduction, considering HAdV, HAV, Salmonella sp. and E. coli quantification. The applicability in real-scale of decentralized treatment systems using household-based biodigesters promoted reduction of 90, 99, 99.99 and 99.999% from HAV, Salmonella sp., E. coli and HAdV from domestic wastewater, respectively; The river water quality improvement before the wastewater treatment application was highlight in the present study, considering that the reduction of waterborne pathogens in this water in 90, 99.99 and 99.999% of E. coli, HAV and HAdV, respectively (Salmonella sp. was not detected in river water). In general, this is an important study for encouraging the decentralized sanitation in vulnerable and poverty area, as well in rural sites, considering the positive impact of this implementation on public health.

Understanding the chemical response and characteristics of bacterial communities in soil is critical to evaluate the effects of selenium (Se) supplement on plant growth and chromium (Cr)/Se uptake in Cr contaminated soil. The rhizosphere soil characteristics of pak choi (Brassica campestris L. ssp. Chinensis Makino) were investigated in soil contaminated with different levels and forms of Cr when supplemented with Se. Although inhibition of plant growth caused by Cr stress was not completely alleviated by Se, Cr content in plant tissues decreased in Cr(VI)120Se5 treatment (Cr(VI): 120 mg kg−1 soil; Se: 5 mg kg−1 soil) and its bioavailability in soil decreased in Cr(III)200Se5 (Cr(III): 200 mg kg−1 soil; Se: 5 mg kg−1 soil) treatment. Moreover, antagonism of Cr and Se on soil enzyme activities and bacterial communities were revealed. Notably, results of Cr(VI) reduction and Se metabolism functional profiles confirmed that bacterial communities play a critical role in regulating Cr/Se bioavailability. Additionally, the increases of Se bioavailability in Cr contaminated soil were ascribed to oxidation of Cr(VI) and reduction of Se reductases proportions, as well as the enhancing of pH in soil. These findings reveal that Se has the potential capacity to sustain the stability of microdomain in Cr contaminated soil.

Whilst numerous studies have explored the spatial patterns and underlying causes of PM₂.₅, little attention has been paid to the spatial heterogeneity of the factors affecting PM₂.₅. In this study, a geographically weighted regression (GWR) model was used to explore the strength and direction of nexus between various factors and PM₂.₅ in Chinese cities. A comprehensive interpretive framework was established, composed of 18 determinants spanning the three categories of natural conditions, socioeconomic factors, and city features. Our results indicate that PM₂.₅ concentration levels were spatially heterogeneous and markedly higher in cities in eastern China than in cities in the west of the country. Based on the results of GWR, significant spatial heterogeneity was identified in both the direction and strength of the determinants at the local scale. Among all of the natural variables, elevation was found to be statistically significant with its effects on PM₂.₅ in 95.60% of the cities and it correlated negatively with PM₂.₅ in 99.63% cities, with its effect gradually weakening from the eastern to the western parts of China. The variable of built-up areas emerged as the strongest variable amongst the socioeconomic variables studied; it maintained a positive significant relationship in cities located in the Pearl River Delta and surrounding areas, while in other cities it exhibited a negative relationship to PM₂.₅. The highest coefficients were located in cities in northeast China. As the strongest variable amongst the six landscape factors, patch density maintained a positive relationship in part of cities. While in cities in the northeast regions, patch density exhibited a negative relationship with PM₂.₅, revealing that increasing urban fragmentation was conducive to PM₂.₅ reductions in those regions. These empirical results provide a basis for the formulation of targeted and differentiated air quality improvement measures in the task of regional PM₂.₅ governances.

Fine particulate matter (Particulate matter with diameter ≤ 2.5 μm) is associated with multiple health outcomes, with varying effects across seasons and locations. It remains largely unknown that which components of PM₂.₅ are most harmful to human health.We systematically searched all the relevent studies published before August 1, 2018, on the associations of fine particulate matter constituents with mortality and morbidity, using Web of Science, MEDLINE, PubMed and EMBASE. Studies were included if they explored the associations between short term or long term exposure of fine particulate matter constituents and natural, cardiovascular or respiratory health endpoints. The criteria for the risk of bias was adapted from OHAT and New Castle Ottawa. We applied a random-effects model to derive the risk estimates for each constituent. We performed main analyses restricted to studies which adjusted the PM₂.₅ mass in their models.Significant associations were observed between several PM₂.₅ constituents and different health endpoints. Among them, black carbon and organic carbon were most robustly and consistently associated with all natural, cardiovascular mortality and morbidity. Other potential toxic constituents including nitrate, sulfate, Zinc, silicon, iron, nickel, vanadium, and potassium were associated with adverse cardiovascular health, while nitrate, sulfate and vanadium were relevant for adverse respiratory health outcomes.Our analysis suggests that black carbon and organic carbon are important detrimental components of PM₂.₅, while other constituents are probably hazardous to human health. However, more studies are needed to further confirm our results.

Polychlorinated biphenyls (PCBs) have been detected as prevalent environmental contaminants in water, food and biota. Previous studies in vitro have shown that a variety of sorbent materials, including carbon, can sorb PCBs; however, PCB sorbents that can be added to food or drinking water to decrease toxin bioavailability in humans and animals have not been reported. To address this problem, we have developed a broad-acting and highly effective sorbent for PCBs using montmorillonite clays reported to be safe for consumption in animals and humans. In this study, calcium montmorillonite clays were acid processed (APMs) and the interactions of six PCB congeners (PCB 77, 126, 153, 157, 154 and 155) on the surfaces of APMs were characterized. Computational models and isothermal analyses were used to derive surface capacities and affinities, delineate mechanisms and predict the thermodynamics of sorption. To confirm the safety and predict the efficacy of APMs against individual PCBs and common mixtures (Aroclors 1254 and 1260), we have also used a living organism (Hydra vulgaris) that is sensitive to toxins. APMs significantly protected hydra against the toxicity of PCBs and Aroclors. This finding was supported by studies showing tight binding; high capacity, affinity, and enthalpy; and a low therapeutic dose.

Pesticide residues most likely coexist with antibiotics due to the application of animal-based fertilizers in agriculture. In this study, the degradation and enantioselectivity of beta-cypermethrin in soil and chicken manure-amended soil were investigated. The effects of oxytetracycline on the soil microbial community were also estimated. The results showed that the half-life of beta-cypermethrin in the soil was 16.9 days and that the (+)-enantiomer was degraded preferentially in both pairs of enantiomers. The metabolites cis/trans-DCCA(3-(2′,2′-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid) and 3-PBA (3-Phenoxybenzoic acid) were detected. The trans-DCCA concentrations ranged from 0.094 to 0.120 mg/kg, which were higher than the concentrations of cis-DCCA (0.091–0.120 mg/kg) and 3-PBA (0.022–0.061 mg/kg). In the presence of oxytetracycline, beta-cypermethrin degradation was inhibited slightly, while the enantioselectivity was not affected. Oxytetracycline increased the enrichment and persistence of the metabolites. Addition of chicken manure decreased the cis-DCCA residue levels in the soil and alleviated the effect of oxytetracycline; however, chicken manure increased the accumulation and persistence of 3-PBA. In addition, oxytetracycline perturbed the structure of the soil microbial community. The abundance of Proteobacteria increased, while the abundances of Firmicutes and Actinobacteria decreased. These changes might affect the biodegradation of beta-cypermethrin and its metabolites. Combined pollution with antibiotics should be considered for its potential impact on pesticide residues.

As one of the highest energy consuming and polluting industries, the power generation industry is an important source of particulate matter emissions. Recently, implementation of ultra-low emission technology has changed the emission characteristic of fine particulate matter (PM2.5). In this study, PM2.5 emitted from four typical power plants in China was sampled using a dilution channel sampling system, and analyzed for elements, water-soluble ions and carbonaceous fractions. The results showed that PM2.5 concentrations emitted from the four power plants were 0.78 ± 0.16, 0.63 ± 0.09, 0.29 ± 0.07 and 0.28 ± 0.01 mg m−3, respectively. Emission factors were 0.004–0.005 g/kg coal, nearly 1–2 orders of magnitude lower than those reported in previous studies. The highest proportions of PM2.5 consisted of organic carbon (OC), SO42−, elemental carbon (EC), NH4+, Al and Cl−. Coefficients of divergence (CDs) were in the ranges 0.22–0.41 (for an individual plant), 0.43–0.69 (among different plants), and 0.60–0.99 (in previous studies). The results indicated that the source profiles of each tested power plant were relatively similar, but differed from those in previous studies. Enrichment factors showed elevated Se and Hg, in accordance with the source markers Se and As. Comparing source profiles with previous studies, the proportion of OC, EC and NH4+ were higher, while the proportion of Al in PM2.5 were relatively lower. The OC/EC ratio became concentrated at ∼5. Results from this study can be used for source apportionment and emission inventory calculations after implementation of ultra-low emission technologies.