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Identifying the contributions of various chlorinated paraffins (CPs) sources in the environment plays an important practical role in the prevention and control of the CPs contamination. However, little is known about how main CP-related emission industries affect the regional atmospheric characteristics of CPs, including CP products industry, metal working industry, and polyvinyl chloride (PVC) industry. In this study, 60 passive air samples were collected from five typical cities in Henan Province, China, which had serious CP pollution and different structures of CP-related emission industry. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) were detected in all samples in concentrations ranging of 2.6-7.7 × 10

During three sampling periods in 2014, systematic investigations were conducted into contamination profiles of ten organophosphate flame retardants (OPFRs) in both suspended particulate phase and water phase in the Yellow River (Henan Area). This research shows that OPFRs exist at lower concentrations in the suspended phase than in the water phase. The median concentration of 10 OPFRs (∑10OPFRs) in the suspended particulate phase was 62.5 ng/g (fluctuating from ND to 6.17 × 103 ng/g, dw), while their median concentration in the water phase was 109 ng/L (fluctuating from 35.6 to 469 ng/L). Among the selected 10 OPFRs, triethylphosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(2-chloroethyl) phosphate (TCEP) were the predominant compounds in the water phase (occupying 91.6% of the ∑10OPFRs), while TCPP, TCEP, and tri-o-tolyl phosphate (o-TCP) were the most common in the suspended particulate phase, accounting for 90.1% of the ∑10OPFRs. Across the three sampling periods, there was no significant seasonable variation for OPFRs either in the water phase or in the suspended particulate phase, except for TCEP and TCPP in the water phase. Compared with research findings relating to concentrations of OPFRs around China and abroad, the OPFRs of the Yellow River (Henan Area) in the water phase were at a moderate level. Suspended particles (SS) had a very important impact on the transportation of OPFRs in the studied area, with about 83.9% of ∑10OPFRs inflow attributed to SS inflow and about 81.7% of ∑10OPFRs outflow attributed to SS outflow. The total annual inflow and outflow of OPFRs were 7.72 × 104 kg and 6.62 × 104 kg in the studied area, respectively.

Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N

BackgroundLignocellulosic biomass for biofuel production was considered as an effective way to develop new energy. However, the efficient sugar conversion of cellulose and practical utilization of lignin are great challenges for sustainable biorefinery. In addition, sugar conversion and lignin utilization are generally performed separately. In this study, high reducing sugar production and multiple lignin nanoparticles preparation were realized in a pattern based on tetrahydrofuran-water (THF-H2O) pretreatment of corn straw (CS). ResultsThe maximum production of the reducing sugar was 26.79 g/l, which was significantly higher than the theoretical yield of 20.65 g/l. Lignin nanoparticles with different sizes ranged from 239 to 798 nm were prepared using dissolved lignin in the supernatant fluid from different THF-H2O pretreatment conditions through self-assembly with introducing water. The formation of lignin particles with different sizes were influenced by soluble lignin characteristics in the pretreatment liquid. The lignin molecular, functional groups, and structure were explored to elucidate the effects on the variation of lignin particles sizes by GPC, FTIR, and 2D-HSQC-NMR. The guaiacyl (G)-type lignin was easier to be dissolved in the mild pretreatment liquid, contributing to form smaller lignin nanoparticles with a good dispersibility. Comparatively, a small content of syringyl- and G-type lignin which caused by the lignin depolymerization retained in the severe pretreatment liquid to form the larger sphere particles. ConclusionsThe optimal pretreatment under TH22 (THF-H2O pretreatment at 120 °C for 2 h) simultaneously realized the utilization of all components in biomass through high reducing sugar production and the smaller lignin particles preparation. This new pattern of CS pretreatment plays a novel perspective for the technical design of lignocellulosic biomass conversion.

This study was conducted in order to explore the seasonal characteristics, climate impact and source of PM2.5 in Xinxiang, China. Daily PM2.5 samples were collected at urban site from January to December in 2015. Average PM2.5 concentration was 100.6 ± 65.8 μg m−3 in Xinxiang, which was several times higher than China Ambient Air Quality Standards (GB3095-2012). Secondary inorganic aerosols (SIA) constituted 70% of the total ionic concentrations. The average concentration of SO42- was 6.4 ± 12.0 μg m−3, which ranked the highest among the water-soluble ions analyzed. Seasonal variations of PM2.5 and its major chemical components were significant, most of them with high values in winter and the lowest values in summer, especially with heavier PM2.5 events (more than 200 μg/m3) in December. SIA and OC on polluted days were 2.1–2.3 times higher than those of on clean days. It was estimated that Fe, Li, Na, Mg, Al, K, Ca and Sr were emitted from crustal sources and Pb, Cr, Ni, Cu, Zn, As, Cd and V were emitted from anthropogenic emissions using the EF values. Analysis using the tracer and PCA/MLR revealed that vehicle exhausts were the most important source of PM2.5, which contributed 26.9% of PM2.5 over the whole study period. This study provides detailed composition data and first comprehensive analysis of PM2.5 in Xinxiang during a whole year.

The concentrations and compositions of polychlorinated naphthalenes (PCNs) in sediments and suspended particulate matters (SPM) in the middle and lower reaches of the Yellow River were investigated. The mean concentrations of PCNs were 7.15 ± 19.3 ng/g dw in the sediment and 38.1 ± 58.4 ng/g dw in SPM. Tri- and tetra-CNs were the dominant homologue groups in most samples. CN-23 was the predominant congener at all sites, and its presence may be attributed to coal combustion. Combustion indicators showed that local combustion source was the main contributor to the PCN concentrations. These sources were related to the energy structure of this region, where coal is the most important energy resource. Human activities, including industrial thermal processes and reservoir construction, were major factors affecting PCN levels and hydrological conditions, which strongly influenced the environmental fate of PCNs in the Yellow River.

Twenty-four PM 2.5 samples were collected at a suburban site of Xinxiang during Chinese Spring Festival (SF) in 2015. 10 water-soluble ions, 19 trace elements and 8 fractions of carbonaceous species in PM 2.5 were analyzed. Potential sources of PM 2.5 were quantitatively apportioned using principal component analysis (PCA)-multivariate linear regressions (MLR). The threat of heavy metals in PM 2.5 was assessed using incremental lifetime cancer risk (ILCR). During the whole period, serious regional haze pollution persisted, the average concentration of PM 2.5 was 111 ± 54 μg m − 3 , with 95.8% and 79.2% of the daily samples exhibiting higher PM 2.5 concentrations than the national air quality standard I and II. Chemical species declined due to holiday effect with the exception of K, Fe, Mg, Al and K + , Cl − , which increased on Chinese New Year (CNY)'s Eve and Lantern Festival in 2015, indicating the injection of firework burning particles in certain short period. PM 2.5 mass closure showed that secondary inorganic species were the dominant fractions of PM 2.5 over the entire sampling (37.3%). 72-hour backward trajectory clusters indicated that most serious air pollution occurred when air masses transported from the Inner Mongolia, Shanxi and Zhengzhou. Health risk assessment revealed that noncancerous effects of heavy metals in PM 2.5 of Xinxiang were unlikely happened, while lifetime cancer risks of heavy metals obviously exceeded the threshold, which might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and first comprehensive analysis of PM 2.5 during the Spring Festival period in Xinxiang.

To evaluate the effects of internal recycle ratio on nitrous oxide (N 2 O) generation, we set up three laboratory-scale anaerobic–anoxic–oxic (A 2 O) wastewater treatment processes, with internal recycle ratios of 100%, 200%, and 300%, respectively. Total nitrogen (TN) removal was markedly enhanced from 45.8% to 61.9%, as the internal recycle ratio increased from 100% to 300%. N 2 O generation was increased from 3.47 to 9.81 × 10 −2 mg/L during the treatment process, with the anoxic section showing the largest N 2 O increment from denitrification. This phenomenon is attributed to the increased amount of nitrate (NO 3 − -N) substrate available for denitrification, due to the increased volume of internal recycle liquid, as well as the increased amount of oxygen, which could restrain the activity of nitrous oxide reductase brought to the anoxic section. Nitrous oxide reductase was more sensitive to oxygen than nitrate and nitrite reductases. Microorganism analysis indicated that the population of nosZ gene-containing bacteria was only slightly affected by the recycle ratio. However, the number of nosZ gene copies decreased as the internal recycle ratio increased from 100% to 300%; this result reveals noticeable decreases in the denitrification capacity of the system for reducing N 2 O to N 2 .

Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10−2 N/m2 to 5.0 × 10−2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2−-N accumulation, leading to a decrease in the N2O–N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).

Particle size is a significant parameter which determines the environmental fate and the behavior of dust particles and, implicitly, the exposure risk of humans to particle-bound contaminants. Currently, the influence of dust particle size on the occurrence and seasonal variation of hexabromocyclododecanes (HBCDs) remains unclear. While HBCDs are now restricted by the Stockholm Convention, information regarding HBCD contamination in indoor dust in China is still limited. We analyzed composite dust samples from offices (n = 22), hotels (n = 3), kindergartens (n = 2), dormitories (n = 40), and main roads (n = 10). Each composite dust sample (one per type of microenvironment) was fractionated into 9 fractions (F1-F9: 2000-900, 900-500, 500-400, 400-300, 300-200, 200-100, 100-74, 74-50, and

This study was conducted in order to explore the seasonal characteristics, climate impact and source of PM