خيارات البحث
النتائج 271 - 280 من 8,010
Effects of the technical ingredient clomazone and its two formulated products on aquatic macrophytes النص الكامل
2021
Stevanović, Marija | Brkić, Dragica | Tomić, Tanja | Mihajlović, Varja | Đorđević, Tijana | Gašić, Slavica
One active ingredient can be a component of different types of formulations of pesticides, while the toxicity of its formulations may vary depending on various constituents used in the mixture. The present study focuses on evaluating the effects of the active ingredient clomazone and its formulations (Rampa® EC and GAT Cenit 36 CS, both containing 360 g a.i./l of clomazone) on non-target aquatic macrophytes. The two formulation types differ in their active ingredient release and presumed environmental impact. In order to cover different ecological traits, two species of aquatic macrophytes – the floating monocot Lemna minor and the rooted dicot Myriophyllum aquaticum, were used as test models. The results of this study revealed differences in the sensitivity of tested plants to clomazone. Based on the most sensitive parameters, M. aquaticum proved to be more sensitive than L. minor to the technical ingredient and both formulations. The species sensitivity distribution (SSD) approach that was tried out in an attempt to create a higher tier step of risk assessment of clomazone for primary producers indicates that tests on rooted macrophytes can add value in risk assessment of plant protection products. The capsule formulation of clomazone was less toxic than the emulsion for L. minor, but more toxic for M. aquaticum. The most toxic for L. minor was the emulsifiable concentrate formulation Rampa® EC, followed by technical clomazone (EC₅₀ 33.3 and 54.0 mg a.i./l, respectively), while the aqueous capsule suspension formulation GAT Cenit 36 CS did not cause adverse effects. On the other hand, the most toxic for M. aquaticum was the formulation GAT Cenit 36 CS, followed by technical clomazone and the formulation Rampa® EC, demonstrating a greater effect of the capsule formulation.
اظهر المزيد [+] اقل [-]The application of hierarchical clustering to analyzing ashes from the combustion of wood pellets mixed with waste materials النص الكامل
2021
Grabowski, Jacek | Smoliński, Adam
Air pollution constitutes the greatest environmental threat to human health in the European Union. In Poland, the emission of particulate matter and harmful gases originating from local coal based boiler plants and the combustion of fuels in residential heating appliances is a considerable source of air pollution. The combustion of fuel in home furnaces is inefficient due to the use of cheap fuels of low heating parameters and the frequent addition of waste. For the purpose of the research, deciduous tree wood pellets were selected as the basic fuel with the admixture of plastic waste, rubber, waste paper, wood residues, diapers, textile waste, multi-material packaging, construction waste, biomass and alternative fuel (RDF). Examining ash samples to confirm the practices of combusting or co-combusting waste materials in heating appliances is considered to be one of the most reliable detection methods; however, the results of direct research require further data processing. The application of hierarchical clustering analysis to the obtained results arranged into a matrix enabled in a simple way to demonstrate the similarities between the examined samples of fuel and the samples of fuel mixed with waste materials in the parameters space as well as to analyze the similarities among the measured parameters (the content of particular elements in ash) in the space of the examined samples. The application of chemometric methods for the purpose of identifying the combusted fuels, and, in particular the co-combusted waste complements the currently used monitoring tools which control the use of low quality fuels or the combustion of waste of different origin.
اظهر المزيد [+] اقل [-]Interactions between Escherichia coli survival and manganese and iron oxides in water under freeze-thaw النص الكامل
2021
Wang, Xu | Yuan, Weilin | Tao, Jiahui | Xu, Meng | Guo, Ping
Pathogenic survivals were dramatically affected by Fe³⁺ and Mn²⁺ under freeze-thaw (FT), and the dissolutions of manganese and iron oxides (MIOs) were also accelerated under FT. But the mutual influences of pathogenic bacterial survival and MIOs under FT have not been profoundly explored yet. In this work, aqueous systems containing Escherichia coli as well as synthetic ferrihydrite (Fh) and manganese dioxide (MnO₂) were experimented under simulated FT cycles to study the mutual influences of metal oxides and bacteria survival while oxide dissolutions and appearances, bacterial morphology and activities (survival number, cell surface hydrophobicity (CSH) and superoxide dismutase (SOD)) were obtained. The results showed that broken E. coli cells by ice growth were observed, but both oxides promoted E. coli survival under FT stress and prolonged bacterial survival time by 1.2–2.9 times, which were mainly attributed to the release of Fe³⁺ and Mn²⁺ caused by FT. The dissolutions of Fh and MnO₂ under FT, which took place at a low level in absence of E. coli cells, were markedly enhanced with bacterial interferences by 2–8 times and higher dissolved manganese concentrations were detected than iron. This was probably because that concentrated organic matters which were released from broken cells, rejected into unfrozen liquid layer and acted as electron donors and ligands to oxide dissolution. Compared with Fh system, more significant promotion of E. coli survival under FT in MnO₂ systems were found because of more SOD generations associated with high dissolved manganese concentrations and the stronger cellular protection by MnO₂ aggregations. The results suggested that FT significantly influenced the interactions between metal oxides and bacterial in water, resulting to changes in pathogen activity and metal element cycling.
اظهر المزيد [+] اقل [-]The human and ecological risks of neonicotinoid insecticides in soils of an agricultural zone within the Pearl River Delta, South China النص الكامل
2021
Yu, Zimin | Li, Xue-Fang | Wang, Shaorui | Liu, Liang-Ying | Zeng, E. Y. (Eddy Y.)
Neonicotinoid insecticides (NIIs) are extensively used worldwide and frequently detected in the environment. The human and ecological risks associated with the occurrence of NIIs in agricultural zones are of high importance. The present study highlights the regional occurrence and human exposure risks of NIIs in agricultural soil within the Pearl River Delta (PRD), South China. Six neonicotinoids, i.e., imidacloprid, clothianidin, acetamiprid, imidaclothiz, dinotefuran, and flonicamid, were measured in 351 soil samples from Zengcheng, a typical agricultural zone. The soil samples were categorized into three groups based on cultivated plants: vegetables, rice, and fruits. At least one of these neonicotinoid insecticides was detected in 95% of the soil samples. The levels of ∑₆NII (range (median)) were 0.26–390 (23), 0.26–280 (6.1), and 0.26–120 (5.0) ng g⁻¹ dry weight in soil samples from vegetable farms, rice paddies, and fruit farms, respectively. Neonicotinoids were detected more frequently and at statistically higher concentrations in vegetable farms than in both rice paddies and fruit farms. This is likely ascribed to higher application frequencies of NIIs in vegetable farms due to higher planting frequencies. The hazard index values for human exposure to NIIs in the agricultural soils were all below 1, suggesting negligible non-cancer risks. The current residual levels of NIIs in the soils could however pose sub-lethal or acute effects to non-target terrestrial organisms such as earthworms. The present study suggests that more information is needed regarding NIIs contamination in soils from agricultural regions of South China to ensure that human and ecological risk from exposure to these compounds can be fully addressed.
اظهر المزيد [+] اقل [-]Distribution of cyclic volatile methylsiloxanes in drinking water, tap water, surface water, and wastewater in Hanoi, Vietnam النص الكامل
2021
Nu Nguyen, Ha My | Khieu, Hanh Thi | Ta, Ngoc Anh | Le, Huong Quang | Nguyen, Trung Quang | Do, Trung Quang | Hoang, Anh Quoc | Kannan, Kurunthachalam | Tran, Tri Manh
In this study, four cyclic volatile methylsiloxanes (cVMSs) were determined in drinking water, tap water, surface water, and wastewater samples collected from Hanoi metropolitan area, Vietnam, during August to December 2020 (dry season) by using solid phase extraction combined with gas chromatography tandem mass spectrometry. Highest concentrations of cVMSs in the range of 63–7400 ng/L (mean/median: 1840/1310 ng/L) were found in wastewater samples. A significant difference existed in the concentrations of cVMSs between influent and effluent of a wastewater treatment plant. The sum concentrations of four cVMSs in lake water, tap water, and bottled water samples were in the ranges of 67.0–1100 ng/L (mean/median: 350/282 ng/L), 19.8–350 ng/L (12.6/12.3 ng/L), and 2.31–28.1 ng/L (10.3/8.23 ng/L), respectively. Among the four cVMSs, decamethylcyclopentasiloxane (D5) was found at the highest concentrations in all water samples analyzed. The mean exposure doses of cVMSs calculated for adults and children through the consumption of drinking were 0.409 and 0.412 ng/kg-bw/day, respectively. Human exposure to cVMSs calculated through drinking water consumption was significantly lower than that reported for inhalation.
اظهر المزيد [+] اقل [-]Effects of using different exposure data to estimate changes in premature mortality attributable to PM2.5 and O3 in China النص الكامل
2021
Wang, Chunlu | Wang, Yiyi | Shi, Zhihao | Sun, Jinjin | Gong, Kangjia | Li, Jingyi | Qin, Momei | Wei, Jing | Li, Tiantian | Kan, Haidong | Hu, Jianlin
The assessment of premature mortality associated with the dramatic changes in fine particulate matter (PM₂.₅) and ozone (O₃) has important scientific significance and provides valuable information for future emission control strategies. Exposure data are particularly vital but may cause great uncertainty in health burden assessments. This study, for the first time, used six methods to generate the concentration data of PM₂.₅ and O₃ in China between 2014 and 2018, and then quantified the changes in premature mortality due to PM₂.₅ and O₃ using the Environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) model. The results show that PM₂.₅-related premature mortality in China decreases by 263 (95% confidence interval (CI95): 142–159) to 308 (CI95: 213–241) thousands from 2014 to 2018 by using different concentration data, while O₃-related premature mortality increases by 67 (CI95: 26–104) to 103 (CI95: 40–163) thousands. The estimated mean changes are up to 40% different for the PM₂.₅-related mortality, and up to 30% for the O₃-related mortality if different exposure data are chosen. The most significant difference due to the exposure data is found in the areas with a population density of around 10³ people/km², mostly located in Central China, for both PM₂.₅ and O₃. Our results demonstrate that the exposure data source significantly affects mortality estimations and should thus be carefully considered in health burden assessments.
اظهر المزيد [+] اقل [-]Blood lead, vitamin D status, and albuminuria in patients with type 2 diabetes النص الكامل
2021
Wang, Bin | Wan, Heng | Cheng, Jing | Chen, Yingchao | Wang, Yuying | Chen, Yi | Chen, Chi | Zhang, Wen | Xia, Fangzhen | Wang, Ningjian | Wang, Li | Lu, Yingli
Environmental lead exposure has been linked with reduced kidney function. However, evidence about its role in diabetic kidney damage, especially when considering the nutritional status of vitamin D, is sparse. In this observational study, we investigated the association between low-level lead exposure and urinary albumin-to-creatinine ratio (UACR) and assessed potential impact of vitamin D among 4033 diabetic patients in Shanghai, China. Whole blood lead was measured by graphite furnace atomic absorption spectrometry. Serum 25-hydroxyvitamin D [25(OH)D] was tested using a chemiluminescence immunoassay. The associations of blood lead with UACR and albuminuria, defined as UACR ≥30 mg/g, according to 25(OH)D levels were analyzed using linear and Poisson regression models. A doubling of blood lead level was associated with a 10.7% higher UACR (95% CI, 6.19%–15.5%) in diabetic patients with 25(OH)D < 50 nmol/L, whereas the association was attenuated toward null (2.03%; 95% CI, −5.18% to 9.78%) in those with 25(OH)D ≥ 50 nmol/L. Similarly, the risk ratios of prevalent albuminuria per doubling of blood lead level between the two groups were 1.09 (95% CI, 1.03–1.15) and 0.99 (95% CI, 0.86–1.14), respectively. Joint analysis demonstrated that a combination of high blood lead and low 25(OH)D corresponded to significantly higher UACR. Among diabetic patients with 25(OH)D < 50 nmol/L, the increment of UACR relative to blood lead was more remarkable in those with reduced estimated glomerular filtration rate (<60 mL/min/1.73 m²). These results suggested that higher blood lead levels were associated with increased urinary albumin excretion in diabetic patients with vitamin D deficiency. Further prospective studies are needed to validate our findings and to determine whether vitamin D supplementation yields a benefit.
اظهر المزيد [+] اقل [-]Differential mitochondrial dysregulation by exposure to individual organochlorine pesticides (OCPs) and their mixture in zebrafish embryos النص الكامل
2021
Lee, Hyojin | Ko, Eun | Shin, Sooim | Choi, Moonsung | Kim, Ki-Tae
Organochlorine pesticides (OCPs) have been reported to cause mitochondrial dysfunction. However, most studies reported its mitochondrial toxicity with respect to a single form, which is far from the environmentally relevant conditions. In this study, we exposed zebrafish embryos to five OCPs: chlordane, heptachlor, p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB), as well as an equal ratio mixture of these OCPs. We evaluated mitochondrial function, including oxygen consumption, the activity of mitochondrial complexes, antioxidant reactions, and expression of genes involved in mitochondrial metabolism. Oxygen consumption rate was reduced by exposure to chlordane, and β-HCH, linking to the increased activity of specific mitochondrial complex I and III, and decreased GSH level. We found that these mitochondrial dysfunctions were more significant in the exposure to the OCP mixture than the individual OCPs. On the mRNA transcription level, the individual OCPs mainly dysregulated the metabolic cycle (i.e., cs and acadm), whereas the OCP mixture disrupted the genes related to mitochondrial oxidative phosphorylation (i.e., sdha). Consequently, we demonstrate that the OCP mixture disrupts mitochondrial metabolism by a different molecular mechanism than the individual OCPs, which warrants further study to evaluate mitochondrial dysregulation by chronic exposure to the OCP mixture.
اظهر المزيد [+] اقل [-]Exploring common factors influencing PM2.5 and O3 concentrations in the Pearl River Delta: Tradeoffs and synergies النص الكامل
2021
Wu, Jiansheng | Wang, Yuan | Liang, Jingtian | Yao, Fei
Particulate matter with an aerodynamic equivalent dimeter less than 2.5 μm (PM₂.₅) and ozone (O₃) are major air pollutants, with coupled and complex relationships. The control of both PM₂.₅ and O₃ pollution requires the identification of their common influencing factors, which has rarely been attempted. In this study, land use regression (LUR) models based on the least absolute shrinkage and selection operator were developed to estimate PM₂.₅ and O₃ concentrations in China's Pearl River Delta region during 2019. The common factors in the tradeoffs between the two air pollutants and their synergistic effects were analyzed. The model inputs included spatial coordinates, remote sensing observations, meteorological conditions, population density, road density, land cover, and landscape metrics. The LUR models performed well, capturing 54–89% and 42–83% of the variations in annual and seasonal PM₂.₅ and O₃ concentrations, respectively, as shown by the 10-fold cross validation. The overlap of variables between the PM₂.₅ and O₃ models indicated that longitude, aerosol optical depth, O₃ column number density, tropospheric NO₂ column number density, relative humidity, sunshine duration, population density, the percentage cover of forest, grass, impervious surfaces, and bare land, and perimeter-area fractal dimension had opposing effects on PM₂.₅ and O₃. The tropospheric formaldehyde column number density, wind speed, road density, and area-weighted mean fractal dimension index had complementary effects on PM₂.₅ and O₃ concentrations. This study has improved our understanding of the tradeoff and synergistic factors involved in PM₂.₅ and O₃ pollution, and the results can be used to develop joint control policies for both pollutants.
اظهر المزيد [+] اقل [-]Pre-migration artificial light at night advances the spring migration timing of a trans-hemispheric migratory songbird النص الكامل
2021
Smith, Reyd A. | Gagné, Maryse | Fraser, Kevin C.
Artificial light at night (ALAN) is increasing at a high rate across the globe and can cause shifts in animal phenology due to the alteration of perceived photoperiod. Birds in particular may be highly impacted due to their use of extra-retinal photoreceptors, as well as the use of photoperiodic cues to time life events such as reproduction, moult, and migration. For the first time, we used light-logging geolocators to determine the amount of ALAN experienced by long-distance migratory songbirds (purple martin; Progne subis) while at their overwintering sites in South America to measure its potential relationship with spring migration timing. Almost a third of birds (48/155; 31%) were subjected to at least one night with ALAN over 30 days prior to spring migration. Birds that experienced the highest number of nights (10+) with artificial light departed for spring migration on average 8 days earlier and arrived 8 days earlier at their breeding sites compared to those that experienced no artificial light. Early spring migration timing due to pre-migration ALAN experienced at overwintering sites could lead to mistiming with environmental conditions and insect abundance on the migratory route and at breeding sites, potentially impacting survival and/or reproductive success. Such effects would be particularly detrimental to species already exhibiting steep population declines such as purple martins and other migratory aerial insectivores.
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