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Transplacental transfer characteristics of organochlorine pesticides in paired maternal and cord sera, and placentas and possible influencing factors 全文
2018
Zhang, Xiaolan | Wu, Xia | Lei, Bingli | Jing, Ye | Jiang, Zi'an | Zhang, Xinyu | Fang, Xiangming | Yu, Yingxin
Organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane (DDT) and its metabolites [dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane], hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB), are widely detected in humans despite the considerable decline in environmental concentrations. To understand the placental transfer of OCPs and the possible maternal influence on them, we measured the concentrations of DDTs, HCHs, and HCB in 102 paired samples of maternal and cord sera, and placentas collected in Shanghai, China. The median concentrations of DDTs and HCHs were the highest in maternal sera (601, 188 ng g⁻¹ lipid), followed by umbilical cord sera (389, 131 ng g⁻¹ lipid), and placentas (65, 37 ng g⁻¹ lipid). 4,4′-DDE, β-HCH, and HCB were the predominant contaminants in the three matrices. The ubiquitous existence of OCPs, and the significant concentration relationships of DDTs, HCHs, and OCPs in the three matrices suggested placental transfer from mother to fetus. The lipid-based concentration ratios of 4,4′-DDE, β-HCH, and HCB in umbilical cord serum to those in maternal serum (F/M), and ratios of placenta to maternal serum (P/M) ranged from 0.66 to 1.01, and 0.12 to 0.25, respectively. Maternal variables affected the levels of fetal contamination. For primiparous women, significant correlations between maternal age and maternal HCHs, and between pre-pregnancy body mass index (BMI) and maternal HCHs were found. The negative effect of parity, and the positive effect of food consumption on maternal OCP concentrations were also observed, although there were no significant differences. The possible influence of parity on F/M and P/M of 4,4′-DDE suggested borderline significant differences between primiparous and multiparous women. Also, slight group differences were observed between elder and younger women, and between overweight and normal/underweight women. Parity seems to have a potential influence on transfer ratios of some OCP pollutants.
显示更多 [+] 显示较少 [-]Concentrations and variability of organophosphate esters, halogenated flame retardants, and polybrominated diphenyl ethers in indoor and outdoor air in Stockholm, Sweden 全文
2018
We investigated the concentrations and temporal variability of organophospate esters (OPEs), halogenated flame retardants (HFRs) and polybrominated diphenyl ethers (PBDEs) in indoor and outdoor urban air in Stockholm, Sweden over one year (2014–2015) period. The median concentrations of the three target chemical groups (OPEs, HFRs, PBDEs) were 1–2 orders of magnitude higher in indoor air than outdoor urban air. OPEs were the most abundant target FRs with median concentrations in indoor (Σ10OPE = 340 000 pg/m3) and outdoor urban (Σ10OPEs = 3100 pg/m3) air, being 3 orders of magnitude greater than for HFRs in indoor (Σ15HFRs = 120 pg/m3) and outdoor urban (Σ15HFRs = 1.6 pg/m3) air. In indoor air, PBDE concentrations (Σ17PBDEs = 33 pg/m3) were lower than for the HFRs, but in outdoor urban air, concentrations (Σ17PBDEs = 1.1 pg/m3) were similar to HFRs. The most abundant OPEs in both the indoor and outdoor urban air were tris(2-butoxyethyl)phosphate (TBOEP), tris(chloroisopropyl)phosphate (TCIPP), tris(2-chloroethyl)phosphate (TCEP), tri-n-butyl-phosphate (TnBP), triphenyl phosphate (TPhP) and tris(1,3-dichloroisopropyl)phosphate (TDCIPP). TCIPP in indoor air was found in the highest concentrations and showed the greatest temporal variability, which ranged from 85 000 to 1 900 000 pg/m3 during the one-year sampling period. We speculate that activities in the building, e.g. floor cleaning, polishing, construction, introduction of new electronics and changes in ventilation rate could explain its variation. Some OPEs (TnBP, TCEP, TCIPP, TDCIPP and TPhP), HFRs/PBDEs (pentabromotoluene, 2, 3-dibromopropyl 2, 4, 6-tribromophenyl ether, hexabromobenzene, BDE-28, -47, and -99) in outdoor urban air showed seasonality, with increased concentrations during the warm period (p < 0.05, Pearson's r ranged from −0.45 to −0.91). The observed seasonality for OPEs was probably due to changes in primary emission, and those for the HFRs and PBDEs was likely due to re-volatilization from contaminated surfaces.
显示更多 [+] 显示较少 [-]Detection of semi-volatile compounds in cloud waters by GC×GC-TOF-MS. Evidence of phenols and phthalates as priority pollutants 全文
2018
Although organic species are transported and efficiently transformed in clouds, more than 60% of this organic matter remains unspeciated. Using GCxGC-HRMS technique we were able to detect and identify over 100 semi-volatile compounds in 3 cloud samples collected at the PUY station (puy de Dôme mountain, France) while they were present at low concentrations in a very small sample volume (<25 mL of cloud water). The vast majority (∼90%) of the detected compounds was oxygenated, while the absence of halogenated organic compounds should be specially mentioned. This could reflect both the oxidation processes in the atmosphere (gas and water phase) but also the need of the compounds to be soluble enough to be transferred and dissolved in the cloud droplets. Furans, esters, ketones, amides and pyridines represent the major classes of compounds demonstrating a large variety of potential pollutants. Beside these compounds, priority pollutants from the US EPA list were identified and quantified. We found phenols (phenol, benzyl alcohol, p-cresole, 4-ethylphenol, 3,4-dimethylphenol, 4-nitrophenol) and dialkylphthalates (dimethylphthalate, diethylphthalate, di-n-butylphthalate, bis-(2-ethylhexyl)-phthalate, butylbenzylphthalate, di-n-octyl phthalate). In general, the concentrations of phthalates (from 0.09 to 52 μg L−1) were much higher than those of phenols (from 0.03 to 0.74 μg L−1). To our knowledge phthalates in clouds are described here for the first time. We investigated the variability of phenols and phthalates concentrations with cloud air mass origins (marine vs continental) and seasons (winter vs summer). Although both factors seem to have an influence, it is difficult to deduce general trends; further work should be conducted on large series of cloud samples collected in different geographic areas and at different seasons.
显示更多 [+] 显示较少 [-]Gene cloning, expression, and reducing property enhancement of nitrous oxide reductase from Alcaligenes denitrificans strain TB 全文
2018
Wang, Yu | Wang, Zeyu | Duo, Yankai | Wang, Xiaoping | Chen, Jianmeng | Chen, Jun
Nitrous oxide (N₂O) is a potent greenhouse gas and tends to accumulate as an intermediate in the process of bacteria denitrification. To achieve complete reduction of nitrogen oxide (NOₓ) in bacteria denitrification, the structural gene nosZ encoding nitrous oxide reductase (N₂OR) was cloned from Alcaligenes denitrificans strain TB (GenBank JQ044686). The recombinant plasmid containing the nosZ gene was built, and the expression of nosZ gene in Escherichia coli was determined. Results show that the nosZ gene consisting of 1917 nucleotides achieves heterologous expression successfully by codon optimization strategy under optimal conditions (pre-induction inoculum OD₆₀₀ of 0.67, final IPTG concentration of 0.5 mM, inducing time of 6 h, and inducing temperature of 28 °C). Determination result of gas chromatography confirms that N₂O degradation efficiency of recombinant E. coli is strengthened by at least 1.92 times compared with that of original strain TB when treated with N₂O as substrate. Moreover, N₂OR activity in recombinant strain is 2.09 times higher than that in wild strain TB, which validates the aforementioned result and implies that the recombinant E. coli BL21 (DE3)-pET28b-nosZ is a potential candidate to control N₂O accumulation and alleviate greenhouse effect. In addition, the N₂OR structure and the possible N₂O binding site in Alcaligenes sp. TB are predicted, which open an avenue for further research on the relationship between N₂OR activity and its structure.
显示更多 [+] 显示较少 [-]Occurrence, elimination, enantiomeric distribution and intra-day variations of chiral pharmaceuticals in major wastewater treatment plants in Beijing, China 全文
2018
Duan, Lei | Zhang, Yizhe | Wang, Bin | Deng, Shubo | Huang, Jun | Wang, Yujue | Yu, Gang
The occurrence, eliminations, enantiomeric distribution and intra-day variations of five chiral pharmaceuticals (three beta-blockers and two antidepressants) were investigated in eight major WWTPs in Beijing, China. The results revealed that metoprolol (MTP) and venlafaxine (VFX) were of the highest concentrations among the five determined pharmaceuticals with mean concentrations of 803 ng L⁻¹ and 408 ng L⁻¹, respectively in influents, and 354 ng L⁻¹ and 165 ng L⁻¹ in effluents, respectively. Their removal efficiencies, intra-day concentration changes and enantiomeric profiles during wastewater treatment were further analyzed. Loads of these two chiral pharmaceuticals were also studied to reveal drug use pattern. A/A/O+MBR (anaerobic/anoxic/oxic + membrane bio-reactor) followed by joint disinfection treatment process exhibited the high removal efficiencies. No or weak enantioselectivity was observed in most WWTPs. However, obvious enantiomeric fraction (EF) changing of MTP was observed in WWTP3 employing A/A/O+MBR. Intra-day concentration fluctuations of MTP were smaller than VFX. A quick response to sudden rise influent concentration of MTP was observed in WWTP1 effluent but EF response lagged behind. Similar bihourly EF variations in influents and effluents were also observed in most WWTPs for MTP and VFX in consideration of hydraulic residence time (HRT).
显示更多 [+] 显示较少 [-]Nitrous oxide emissions in Chinese vegetable systems: A meta-analysis 全文
2018
Wang, Xiaozhong | Zou, Chunqin | Gao, Xiaopeng | Guan, Xilin | Zhang, Wushuai | Zhang, Yueqiang | Shi, Xiaojun | Chen, Xinping
China accounts for more than half of the world's vegetable production, and identifying the contribution of vegetable production to nitrous oxide (N₂O) emissions in China is therefore important. We performed a meta-analysis that included 153 field measurements of N₂O emissions from 21 field studies in China. Our goal was to quantify N₂O emissions and fertilizer nitrogen (N) based-emission factors (EFs) in Chinese vegetable systems and to clarify the effects of rates and types of N fertilizer in both open-field and greenhouse systems. The results indicated that the intensive vegetable systems in China had an average N₂O emission of 3.91 kg N₂O-N ha⁻¹ and an EF of 0.69%. Although the EF was lower than the IPCC default value of 1.0%, the average N₂O emission was generally greater than in other cropping systems due to greater input of N fertilizers. The EFs were similar in greenhouse vs. open-field systems but N₂O emissions were about 1.4 times greater in greenhouses. The EFs were not affected by N rate, but N₂O emissions for both open-field and greenhouse systems increased with N rate. The total and fertilizer-induced N₂O emissions, as well as EFs, were unaffected by the type of fertilizers in greenhouse system under same N rates. In addition to providing basic information about N₂O emissions from Chinese vegetable systems, the results suggest that N₂O emissions could be reduced without reducing yields by treating vegetable systems in China with a combination of synthetic N fertilizer and manure at optimized economic rates.
显示更多 [+] 显示较少 [-]Modeling nitrous oxide emissions from digestate and slurry applied to three agricultural soils in the United Kingdom: Fluxes and emission factors 全文
2018
Shen, Jiacheng | Treu, Roland | Wang, Junye | Nicholson, Fiona | Bhogal, Anne | Thorman, Rachel
Organic fertilizers, such as digestates and manure, are increasingly applied in agricultural systems because of the benefits they provide in terms of plant nutrients and soil quality. However, there are few investigations of N₂O emissions following digestate application to agricultural soils using process-based models. In this study, we modified the UK-DNDC model to include digestate applications to soils by adding digestate properties to the model and considering the effect of organic fertilizer pH. Using the modified model, N₂O emissions were simulated from two organic fertilizers (digested food waste and livestock slurry) applied to three farms in the United Kingdom: one growing winter wheat at Wensum (WE) and two grasslands at Pwllpeiran (PW) and North Wyke (NW). The annual cumulative gross (i.e. not excluding control emission) N₂O emissions were calculated using MATLAB trapezoidal numerical integration. The relative errors of the modeled annual cumulative emissions to the measured emissions ranged from −5.4% to 48%. Two-factor models, including linear, exponential and hyperbola responses, correlating total N loading and soil clay content to calculations of N₂O emissions and N₂O emission factors (EFs) were developed for calculations of emission fluxes and EFs. The squares of the correlation coefficients of the measured and two-factor linear modeled emissions were 0.998 and 0.999 for digestate and slurry, respectively, and the corresponding squares of correlation coefficients of the EFs were 0.998 and 0.938. The two-factor linear model also predicted that the EFs increased linearly with decreasing clay content and the maximum EFs for digestate and slurry were 0.95 and 0.76% of total N applied, respectively. This demonstrates that the modified UK_DNDC is a good tool to simulate N₂O emission from digestate and slurry and to calculate UK EFs using TIER 3 methodology..
显示更多 [+] 显示较少 [-]Effects of a glyphosate-based herbicide on Fucus virsoides (Fucales, Ochrophyta) photosynthetic efficiency 全文
2018
Falace, Annalisa | Tamburello, Laura | Guarnieri, G. (Giuseppe) | Kaleb, Sara | Papa, Loredana | Fraschetti, Simonetta
Herbicides are increasingly recognised as sources of water pollution. Glyphosate-based herbicides (GBHs) are widely used because of their low cost and high effectiveness. By measuring the photosynthetic efficiency of Fucus virsoides fronds exposed to a GBH (Roundup® Power 2.0), we investigated the effect of a continuous exposure (6 days) and the potential of recovery after a short exposure (24 h). Both experiments were carried out combining GBH with and without nutrient enrichment, simulating a runoff event. A factorial experimental design allowed us to assess the potential of interactions between GBH and nutrients, which are likely to co-occur in coastal areas. Our results show deleterious effects of GBH at low concentration on F. virsoides, independently from the duration of exposure and the presence of nutrients.
显示更多 [+] 显示较少 [-]Bioaccumulation of microcystin congeners in soil-plant system and human health risk assessment: A field study from Lake Taihu region of China 全文
2018
Cao, Qing | Steinman, Alan D. | Wan, Xiang | Xie, Liqiang
A 120-day field study was carried out near Lake Taihu to evaluate the bioaccumulation of microcystin (MC) congeners in a soil-plant system, as well as to assess human health risk when consuming edible plants irrigated with MCs-contaminated water. Natural cyanobacteria bloom-containing lake water (lake water) and half-diluted natural cyanobacteria bloom-containing lake water with tap water (half-lake water) were used to irrigate lettuce and rice. An additional treatment involving fertilization with a cyanobacteria bloom was applied just to the lettuce experiment. MCs in soils, roots, leaves and grains (rice) were detected. In the soil-lettuce system, the three MC congeners in soils fertilized with a cyanobacteria bloom were not detected. The highest concentrations of MCs detected in soils, lettuce roots and leaves were 24.8 (MC-LR 10.1, MC-RR 10.5, MC-YR 4.2) μg kg−1, 424 (MC-LR 168, MC-RR 194, MC-YR 61.5) μg kg−1 and 183 (MC-LR 78.0, MC-RR 76.8, MC-YR 28.1) μg kg−1, respectively, in the lake water treatment. In the soil-rice system, the highest concentration of MCs was accumulated in roots 1504 (MC-LR 634, MC-RR 573, MC-YR 297) μg kg−1, in the lake water treatment. However, the concentration of MCs that accumulated in grains was extremely low with a total MCs concentration of 5.2 (MC-LR 2.1, MC-RR 2.0, MC-YR 1.1) μg kg−1 in the lake water treatment. According to the estimated daily intake (EDI) value, fertilizing with an appropriate amount (0.2% or less, w/w, dry weight (DW)) of a cyanobacteria bloom, as well as consuming rice irrigated with lake water would not pose a threat to human health. However, the EDI values for both adults and children reached tolerable daily intake (TDI) value, assuming they consumed lettuce irrigated with lake water. Results obtained from the growth and yield indicators suggest that MCs bioaccumulation in edible plants is not necessarily coupled with phytotoxic effects.
显示更多 [+] 显示较少 [-]The cold effect of ambient temperature on ischemic and hemorrhagic stroke hospital admissions: A large database study in Beijing, China between years 2013 and 2014—Utilizing a distributed lag non-linear analysis 全文
2018
Luo, Yanxia | Li, Haibin | Huang, Fangfang | Van Halm-Lutterodt, Nicholas | Qin, Xu | Wang, Anxin | Guo, Jin | Tao, Lixin | Li, Xia | Liu, Mengyang | Zheng, Deqiang | Chen, Sipeng | Zhang, Feng | Yang, Xinghua | Tan, Peng | Wang, Wei | Xie, Xueqin | Guo, Xiuhua
The effects of ambient temperature on stroke death in China have been well addressed. However, few studies are focused on the attributable burden for the incident of different types of stroke due to ambient temperature, especially in Beijing, China. We purpose to assess the influence of ambient temperature on hospital stroke admissions in Beijing, China. Data on daily temperature, air pollution, and relative humidity measurements and stroke admissions in Beijing were obtained between 2013 and 2014. Distributed lag non-linear model was employed to determine the association between daily ambient temperature and stroke admissions. Relative risk (RR) with 95% confidence interval (CI) and Attribution fraction (AF) with 95% CI were calculated based on stroke subtype, gender and age group. A total number of 147, 624 stroke admitted cases (including hemorrhagic and ischemic types of stroke) were documented. A non-linear acute effect of cold temperature on ischemic and hemorrhagic stroke hospital admissions was evaluated. Compared with the 25th percentile of temperature (1.2 °C), the cumulative RR of extreme cold temperature (first percentile of temperature, −9.6 °C) was 1.51 (95% CI: 1.08–2.10) over lag 0–14 days for ischemic type and 1.28 (95% CI: 1.03–1.59) for hemorrhagic stroke over lag 0–3 days. Overall, 1.57% (95% CI: 0.06%–2.88%) of ischemic stroke and 1.90% (95% CI: 0.40%–3.41%) of hemorrhagic stroke was attributed to the extreme cold temperature over lag 0–7 days and lag 0–3 days, respectively. The cold temperature's impact on stroke admissions was found to be more obvious in male gender and the youth compared to female gender and the elderly. Exposure to extreme cold temperature is associated with increasing both ischemic and hemorrhagic stroke admissions in Beijing, China.
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