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Результаты 651-660 из 4,309
Development of polyurethane-based passive samplers for ambient monitoring of urban-use insecticides in water Полный текст
2017
Liao, Chunyang | Richards, Jaben | Taylor, Allison R. | Gan, Jay
Widespread use of insecticides for the control of urban pests such as ants, termites, and spiders has resulted in contamination and toxicity in urban aquatic ecosystems in different regions of the world. Passive samplers are a convenient and integrative tool for in situ monitoring of trace contaminants in surface water. However, the performance of a passive sampler depends closely on its affinity for the target analytes, making passive samplers highly specific to the types of contaminants being monitored. The goal of this study was to develop a passive sampler compatible with a wide range of insecticides, including the strongly hydrophobic pyrethroids and the weakly hydrophobic fipronil and organophosphates. Of six candidate polymeric thin films, polyurethane film (PU) was identified to be the best at enriching the test compounds. The inclusion of stable isotope labeled analogs as performance reference compounds (PRCs) further allowed the use of PU film for pyrethroids under non-equilibrium conditions. The PU sampler was tested in a large aquarium with circulatory water flow, and also deployed at multiple sites in surface streams in southern California. The concentrations of pesticides derived from the PU sampler ranged from 0.5 to 18.5 ng/L, which were generally lower than the total chemical concentration measured by grab samples, suggesting that suspended particles and dissolved organic matter in water rendered them less available. The influence of suspended particles and dissolved organic matter on bioavailability was more pronounced for pyrethroids than for fipronils. The results show that the developed PU film sampler, when coupled with PRCs, may be used for rapid and sensitive in-situ monitoring of a wide range of insecticides in surface water.
Показать больше [+] Меньше [-]Response of soil microbial communities and microbial interactions to long-term heavy metal contamination Полный текст
2017
Li, Xiaoqi | Meng, Delong | Li, Juan | Yin, Huaqun | Liu, Hongwei | Liu, Xueduan | Cheng, Cheng | Xiao, Yunhua | Liu, Zhenghua | Yan, Mingli
Due to the persistence of metals in the ecosystem and their threat to all living organisms, effects of heavy metal on soil microbial communities were widely studied. However, little was known about the interactions among microorganisms in heavy metal-contaminated soils. In the present study, microbial communities in Non (CON), moderately (CL) and severely (CH) contaminated soils were investigated through high-throughput Illumina sequencing of 16s rRNA gene amplicons, and networks were constructed to show the interactions among microbes. Results showed that the microbial community composition was significantly, while the microbial diversity was not significantly affected by heavy metal contamination. Bacteria showed various response to heavy metals. Bacteria that positively correlated with Cd, e.g. Acidobacteria_Gp and Proteobacteria_thiobacillus, had more links between nodes and more positive interactions among microbes in CL- and CH-networks, while bacteria that negatively correlated with Cd, e.g. Longilinea, Gp2 and Gp4 had fewer network links and more negative interactions in CL and CH-networks. Unlike bacteria, members of the archaeal domain, i.e. phyla Crenarchaeota and Euryarchaeota, class Thermoprotei and order Thermoplasmatales showed only positive correlation with Cd and had more network interactions in CH-networks. The present study indicated that (i) the microbial community composition, as well as network interactions was shift to strengthen adaptability of microorganisms to heavy metal contamination, (ii) archaea were resistant to heavy metal contamination and may contribute to the adaption to heavy metals. It was proposed that the contribution might be achieved either by improving environment conditions or by cooperative interactions.
Показать больше [+] Меньше [-]Temperature exposure during pregnancy and birth outcomes: An updated systematic review of epidemiological evidence Полный текст
2017
Zhang, Yunquan | Yu, Chuanhua | Wang, Lu
Seasonal patterns of birth outcomes have been observed worldwide, and there was increasing evidence that ambient temperature played as a trigger of adverse birth outcomes, such as preterm birth (PTB), low birth weight (LBW), and stillbirth. To systematically review updated epidemiological evidence about the relationship between temperature exposure during pregnancy and PTB, LBW, and stillbirth, we searched for related studies published in English from electronic databases and references of identified papers. We only included original articles that directly reported the effects of prenatal temperature exposure on birth outcomes. The characteristics and main findings of included studies were examined. A total of 36 epidemiological studies were finally included in this review. Most of these studies focused on PTB and LBW, while less attention has been paid to stillbirth that was relatively rare in the occurrence. Several designs including ecological (e.g., descriptive and time-series) and retrospective cohort studies (e.g., case-crossover and time-to-event) were applied to assess temperature effects on birth outcomes. Temperature metrics and exposure windows varied greatly in these investigations. Exposure to high temperature was generally found to be associated with PTB, LBW, and stillbirth, while several studies also reported the adverse impact of low temperature on birth outcomes of PTB and LBW. Despite no conclusive causality demonstrated, the current evidence for adverse effect on birth outcomes was stronger for heat than for cold. In summary, the evidence linking birth outcomes with ambient temperature was still very limited. Consequently, more related studies are needed worldwide and should be conducted in diversified climate zones, so as to further ascertain the association between temperature and birth outcomes. Future studies should focus on more sophisticated study designs, more accurate estimation of temperature exposure during pregnancy, and more efficient methods to find out the exposure windows, as well as cold-related effects on birth outcomes.
Показать больше [+] Меньше [-]Relationships between acrylamide and glycidamide hemoglobin adduct levels and allergy-related outcomes in general US population, NHANES 2005–2006 Полный текст
2017
Guo, Jing | Yu, Dongdong | Lv, Na | Bai, Rongpan | Xu, Chunjing | Cao, Weiming | Chen, Guangdi
Acrylamide-induced immunotoxicity and allergic dermatitis have been reported in animal experiments and clinical reports, respectively. However, epidemiological evidence from the general population is limited.The purpose of the present study was to estimate the associations between acrylamide exposure and allergy-related outcomes in the general US population.A total of 6982 subjects were selected from the National Health and Nutrition Examination Survey 2005–2006 (NHANES). Internal exposure was measured by the hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA). Allergy-related outcomes including asthma, hay fever, allergy, itchy rash, sneeze, wheeze and eczema were obtained by self-administered questionnaires. Allergic sensitization was assessed by the total immunoglobulin E (IgE) levels. The associations of HbAA and HbGA quartiles with allergy-related outcomes were calculated using logistic regression models with multivariable adjustments. Analyses were additionally stratified according to age, gender and serum cotinine levels.When setting quartile 1 of HbAA as reference, the odds ratios (ORs) [95% confidence intervals (CIs)] of quartile 2 to 4 for eczema were 1.18 (0.79–1.76), 1.14 (0.73–1.78) and 1.58 (1.14–2.18), respectively (ptrend = 0.002). Individuals at the highest quartile of HbGA had significantly elevated likelihoods of itchy rash (OR = 1.37, 95% CI = 1.02–1.83, ptrend = 0.032) and eczema (OR = 1.45, 95% CI = 1.06–1.97, ptrend = 0.044). The stratification analyses indicated various results in different subgroups.This study indicated significant associations between HbAA and HbGA levels and the likelihoods of allergy-related outcomes in the general US population, depending on age, gender and smoke exposure status. These findings suggested potential public health concerns for the widespread exposure to acrylamide.
Показать больше [+] Меньше [-]Sampling design and required sample size for evaluating contamination levels of 137Cs in Japanese fir needles in a mixed deciduous forest stand in Fukushima, Japan Полный текст
2017
Oba, Yurika | Yamada, Toshihiro
We estimated the sample size (the number of samples) required to evaluate the concentration of radiocesium (¹³⁷Cs) in Japanese fir (Abies firma Sieb. & Zucc.), 5 years after the outbreak of the Fukushima Daiichi Nuclear Power Plant accident. We investigated the spatial structure of the contamination levels in this species growing in a mixed deciduous broadleaf and evergreen coniferous forest stand. We sampled 40 saplings with a tree height of 150 cm–250 cm in a Fukushima forest community. The results showed that: (1) there was no correlation between the ¹³⁷Cs concentration in needles and soil, and (2) the difference in the spatial distribution pattern of ¹³⁷Cs concentration between needles and soil suggest that the contribution of root uptake to ¹³⁷Cs in new needles of this species may be minor in the 5 years after the radionuclides were released into the atmosphere. The concentration of ¹³⁷Cs in needles showed a strong positive spatial autocorrelation in the distance class from 0 to 2.5 m, suggesting that the statistical analysis of data should consider spatial autocorrelation in the case of an assessment of the radioactive contamination of forest trees. According to our sample size analysis, a sample size of seven trees was required to determine the mean contamination level within an error in the means of no more than 10%. This required sample size may be feasible for most sites.
Показать больше [+] Меньше [-]Novel pollutants in the Moscow atmosphere in winter period: Gas chromatography-high resolution time-of-flight mass spectrometry study Полный текст
2017
Mazur, D.M. | Polyakova, O.V. | Artaev, V.B. | Lebedev, A.T.
The most common mass spectrometry approach analyzing contamination of the environment deals with targeted analysis, i.e. detection and quantification of the selected (priority) pollutants. However non-targeted analysis is becoming more often the method of choice for environmental chemists. It involves implementation of modern analytical instrumentation allowing for comprehensive detection and identification of the wide variety of compounds of the environmental interest present in the sample, such as pharmaceuticals and their metabolites, musks, nanomaterials, perfluorinated compounds, hormones, disinfection by-products, flame retardants, personal care products, and many others emerging contaminants. The paper presents the results of detection and identification of previously unreported organic compounds in snow samples collected in Moscow in March 2016. The snow analysis allows evaluation of long-term air pollution in the winter period. Gas chromatography coupled to a high resolution time-of-flight mass spectrometer has enabled us with capability to detect and identify such novel analytes as iodinated compounds, polychlorinated anisoles and even Ni-containing organic complex, which are unexpected in environmental samples. Some considerations concerning the possible sources of origin of these compounds in the environment are discussed.
Показать больше [+] Меньше [-]Polychlorinated biphenyls and its potential role in endometriosis Полный текст
2017
Yao, Mengyun | Hu, Tingting | Wang, Yinfeng | Du, Yongjiang | Hu, Changchang | Wu, Ruijin
With the progress of global industrialization and environmental deterioration, the relationship between human health and the living environment has become an increasing focus of attention. Polychlorinated biphenyls (PCBs, including dioxin-like polychlorinated biphenyls and non-dioxin-like polychlorinated biphenyls), as part of the organic chlorine contaminants, have been suspected as playing a role in the etiopathogenesis of endometriosis. Several population-based studies have proposed that exposure to PCBs may increase the risk of developing endometriosis, while some epidemiological studies have failed to find any association between PCBs and endometriosis. The purpose of this review is to discuss the potential pathophysiological relationship between endometriosis and PCBs with a focus on both dioxin-like polychlorinated biphenyls and non-dioxin-like polychlorinated biphenyls.
Показать больше [+] Меньше [-]A flow-through aqueous standard generation system for thin film microextraction investigations of UV filters and biocides partitioning to different environmental compartments Полный текст
2017
Ahmadi, Fardin | Sparham, Chris | Pawliszyn, Janusz
In this paper problems associated with preparation of aqueous standard of highly hydrophobic compounds such as partial precipitation, being lost on the surfaces, low solubility in water and limited sample volume for accurate determination of their distribution coefficients are addressed. The following work presents two approaches that utilize blade thin film microextraction (TFME) to investigate partitioning of UV filters and biocides to humic acid (dissolved organic carbon) and sediment. A steady-state concentration of target analytes in water was generated using a flow-through aqueous standard generation (ASG) system. Dialysis membranes, a polytetrafluoroethylene permeation tube, and a frit porous (0.5 μm) coated by epoxy glue were basic elements used for preparation of the ASG system. In the currently presented study, negligible depletion TFME using hydrophilic-lipophilic balance (HLB) and octadecyl silica-based (C18) sorbents was employed towards the attainment of free concentration values of target analytes in the studied matrices. Thin film geometry provided a large volume of extraction phase, which improved the sensitivity of the method towards highly matrix-bound analytes. Extractions were performed in the equilibrium regime so as to prevent matrix effects and with aims to reach maximum method sensitivity for all analytes under study. Partitioning of analytes on dissolved organic carbon (DOC) was investigated in ASG to facilitate large sample volume conditions. Binding percentages and DOC distribution coefficients (Log KDOC) ranged from 20 to 98% and 3.71–6.72, respectively. Furthermore, sediment-water partition coefficients (Kd), organic-carbon normalized partition coefficients (Log KOC), and DOC distribution coefficients (Log KDOC) were investigated in slurry sediment, and ranged from 33 to 2860, 3.31–5.24 and 4.52–5.75 Lkg-1, respectively. The obtained results demonstrated that investigations utilizing ASG and TFME can yield reliable binding information for compounds with high log KOW values. This information is useful for study of fate, transport, and ecotoxicological effects of UV filters and biocides in aquatic environment.
Показать больше [+] Меньше [-]Application of a spatially resolved model to contextualise monitoring data for risk assessment of down-the-drain chemicals over large scales Полный текст
2017
Kilgallon, John | Franco, Antonio | Price, Oliver R. | Hodges, Juliet E.H.
Many regulatory screening level exposure assessments are based on simple large scale conceptual scenarios. However, exposure, and therefore risks associated with chemicals, are characterised by high spatial variability. The Scenario assembly tool (ScenAT) is a global screening level model to enable spatially resolved local predictions of environmental concentrations of home and personal care chemicals. It uses the European Union Technical Guidance Document (TGD) equation to predict local scale freshwater concentrations (predicted environmental concentrations - PECs) of chemicals discharged via wastewater. ScenAT uses Geographic Information System (GIS) layers for the underlying socio-economic (population) and environmental parameters (per capita water use, sewage treatment plant connectivity, dilution factor). Using a probabilistic approach, we incorporate sources of uncertainty in the input data (tonnage estimation, removal in sewage treatment plants and seasonal variability in dilution factors) for two case-study chemicals: the antimicrobial triclosan (TCS) and the anionic surfactant linear alkylbenzene sulphonate (LAS). We then compare model estimates of wastewater and freshwater concentrations of TCS and LAS to UK monitoring data. Comparison showed that modeled PECs were on average higher than mean measured data for TCS and LAS by a factor 1.8 and 1.4, respectively. Considering the uncertainty associated with both model and monitoring data, the use of a probabilistic approach using the ScenAT model for screening assessment is reasonable. The combination of modelled and monitoring data enables the contextualisation of monitoring data. Spatial PECs can be used to identify areas of elevated concentration for further refined assessment.A probabilistic approach for large scale screening assessments to contextualise monitoring data for risk assessment.
Показать больше [+] Меньше [-]Distinct physiological and molecular responses in Arabidopsis thaliana exposed to aluminum oxide nanoparticles and ionic aluminum Полный текст
2017
Jin, Yujian | Fan, Xiaoji | Li, Xingxing | Zhang, Zhenyan | Sun, Liwei | Fu, Zhengwei | Lavoie, Michel | Pan, Xiangliang | Qian, Haifeng
Nano-aluminium oxide (nAl2O3) is one of the most widely used nanomaterials. However, nAl2O3 toxicity mechanisms and potential beneficial effects on terrestrial plant physiology remain poorly understood. Such knowledge is essential for the development of robust nAl2O3 risk assessment. In this study, we studied the influence of a 10-d exposure to a total selected concentration of 98 μM nAl2O3 or to the equivalent molar concentration of ionic Al (AlCl3) (196 μM) on the model plant Arabidopsis thaliana on the physiology (e.g., growth and photosynthesis, membrane damage) and the transcriptome using a high throughput state-of-the-art technology, RNA-seq. We found no evidence of nAl2O3 toxicity on photosynthesis, growth and lipid peroxidation. Rather the nAl2O3 treatment stimulated root weight and length by 48% and 39%, respectively as well as photosynthesis opening up the door to the use of nAl2O3 in biotechnology and nano agriculture. Transcriptomic analyses indicate that the beneficial effect of nAl2O3 was related to an increase in the transcription of several genes involved in root growth as well as in root nutrient uptake (e.g., up-regulation of the root hair-specific gene family and root development genes, POLARIS protein). By contrast, the ionic Al treatment decreased shoot and root weight of Arabidopsis thaliana by 57.01% and 45.15%, respectively. This toxic effect was coupled to a range of response at the gene transcription level including increase transcription of antioxidant-related genes and transcription of genes involved in plant defense response to pathogens. This work provides an integrated understanding at the molecular and physiological level of the effects of nAl2O3 and ionic Al in Arabidopsis.
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