Refinar búsqueda
Resultados 1711-1720 de 6,548
Selenium sources differ in their potential to alleviate the cadmium-induced testicular dysfunction Texto completo
2020
Zhang, Cong | Huang, Yan | Talukder, Milton | Ge, Jing | Lv, Mei-Wei | Bi, Shao-Shuai | Li, Jin-Long
Cadmium (Cd), a major environmental contaminant, is closely associated with male reproductive health. Selenium (Se) has been recognized as an effective chemo-protectant against Cd toxicity, but the underlying mechanisms remain unclear. The objective of present study was to illustrate the toxic effect of Cd on testis, and then compare the antagonistic effect among different Se sources on growth performance, testicular damage, ion homeostasis, antioxidative potential, and the expression of selenotranscriptome and biosynthetic related factors in Cd-treated chicken. Male chickens were fed with (Ⅰ) Control group: basal diet; (Ⅱ) Cd group: basal diet with 140 mg/kg CdCl₂; (Ⅲ) YSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 3 mg/kg Yeast-Se; (Ⅳ) NSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 1 mg/kg Nano-Se; (Ⅴ) SSe + Cd group: basal diet with 140 mg/kg CdCl₂ and 3 mg/kg Na₂SeO₃. It was observed that different Se treatments dramatically alleviated Cd-induced testicular developmental disorder, ion homeostasis disorder, hormone secretion disorder and oxidative stress. Simultaneously, Se mitigated Cd-induced testicular toxicity by regulating selenoprotein biosynthetic related factors to promote selenoprotein transcription. Finally, this study indicated that dietary supplementation of Yeast-Se produced an acceptable Se form to protect testis from Cd exposure.
Mostrar más [+] Menos [-]A 3D-hydrodynamic model for predicting the environmental fate of chemical pollutants in Xiamen Bay, southeast China Texto completo
2020
Ma, Liya | Lin, Bin-Le | Chen, Can | Horiguchi, Fumio | Eriguchi, Tomomi | Li, Yongyu | Wang, Xinhong
Simulation model is very essential for predicting the environmental fate and the potential environmental consequences of chemical pollutants including those from accidental chemical spills. However very few of such simulation model is seen related to Chinese costal water body. As the first step toward our final goal to develop a simulation model for the prediction and the risk assessment of chemical pollutants in Chinese coastal water, this study developed a three-dimensional (3D) hydrodynamic model of Xiamen Bay (XMB). This hydrodynamic model was externally derived by meteorological data, river discharge and boundary conditions of XMB. We used the model to calculate the physical factors, especially water temperature, salinity and flow field, from June to September 2016 in XMB. The results demonstrated a good match between observations and simulations, which underscores the feasibility of this model in predicting the spatial-temporal concentration of chemical pollutants in the coastal water of XMB. Longitudinal salinity distributions and the mixing profile of river-sea interactions are discussed, including the obvious gradation of salinity from the river towards sea sites shown by the model. We further assumed that 1000 kg and 1000 mg/L of a virtual chemical pollutant leaked out from Jiulong River (JR) estuary (point source) and whole XMB (non-point source), respectively. The model illustrates that it takes three months for XMB to become purified when point source pollution occurs in the estuary, while half a year to be required in the case of non-point source pollution across the entire bay. Moreover, the model indicated that pollutants can easily accumulate in the western coastal zone and narrow waters like Maluan Bay, which can guide environmental protection strategies.
Mostrar más [+] Menos [-]Estimation of the emissions by transport in two port cities of the northeastern Mediterranean, Greece Texto completo
2020
Fameli, K.M. | Kotrikla, A.M. | Psanis, C. | Biskos, G. | Polydoropoulou, A.
Air pollution is one of the most important branches of environmental science as it affects human health, climate and ecosystems. Emissions of air pollutants from transport (vehicles and ships) in port cities strongly affect air quality at local scales, warranting for a combination of theoretical and experimental studies to identify pollution hotspots. The purpose of this paper is to provide a methodology for developing a hybrid emission inventory from transport sector for two port cities located respectively on the Northern Aegean islands of Chios and Lesvos. Emission inventories were constructed for the year 2014 based on top-down and bottom-up approaches. Official data from local authorities and survey results were used for the calculation of emissions. Traffic emissions were spatially allocated to the road network based on population data and hourly traffic counts, and distributed over time (on an hourly basis) with the use of local temporal coefficients.Regarding carbon monoxide road emissions, the highest quantities are mainly emitted by Passenger Cars (43%,32% in Chios and Lesvos respectively) while for PM₁₀ emissions, trucks have the largest share (66% in Chios and 86% in Lesvos). The pollutants that are emitted in greater quantities from the ships at the ports of Mytilene and Chios are NOₓ, followed by SO₂ and CO. Most of the ship emissions in the ports occur by the ships at berth, as they remain berthed for hours whereas maneuvering lasts 15–20 min. As for the daily contribution of the two transport sources to the pollution profile of Mytilene, road emissions are higher for almost all pollutants. However, the contribution of ship emissions is not negligible, especially during the touristic period when marine traffic increases and emissions close to the port area become more important than those from road transport.
Mostrar más [+] Menos [-]Reduced phytotoxicity of nonylphenol on tomato (Solanum lycopersicum L.) plants by earthworm casts Texto completo
2020
Jiang, Lei | Wang, Bingjie | Liang, Jingqi | Pan, Bo | Yang, Yi | Lin, Yong
Concentrations as high as thousands of milligrams per kilogram (dry weight) of nonylphenol (NP), an endocrine-disrupting chemical of great concern, have been reported in soil. Soil is considered one of the primary pathways for exposure of crop plants to NP. However, there have been few studies on the toxicity of soil NP to crop plants, especially with comprehensive consideration of the application of organic fertiliser which is a common agricultural practice. In this study, tomato plants were grown in soils treated with NP in the presence and/or absence of earthworm casts (EWCs). After four weeks, we tested the physiological and biochemical responses (accumulative levels of hydrogen peroxide (H₂O₂) and superoxide anion radicals (O₂-·), total chlorophyll content, degree of membrane lipid peroxidation, activities of defence-related enzymes, and level of DNA damage) and the changes in plant growth (elongation and biomass). The growth inhibition, reactive oxygen species (H₂O₂ and O₂-·) accumulation, decrease in chlorophyll content, increase in activity of defence-related enzymes (including superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione S-transferase and glutathione reductase), enhancement of membrane lipid peroxidation, and DNA damage in NP-treated seedlings were clearly reversed by the intervention of EWCs. In particular, the suppressed elongation, biomass, and chlorophyll content in tomato plants exposed to NP alone were significantly restored by EWCs to even greater levels than those of the undisturbed control. In other words, EWCs could efficiently invigorate the photosynthesis of crops via up-regulating the chlorophyll content, thereby overwhelming the NP stress on plant growth. Accordingly, except for reducing the bioavailability of soil NP as reported in our previous study, EWCs could also help crop plants to cope with NP stress by strengthening their stress resistance ability. Our findings are of practical significance for the formulation of strategies to relieve the negative effects of soil NP on crop growth.
Mostrar más [+] Menos [-]Sub micron aerosol variability and its ageing process at a high altitude site in India: Impact of meteorological conditions Texto completo
2020
Mukherjee, Subrata | Singla, Vyoma | Meena, Guman Singh | Aslam, Mohammad Yusuf | Safai, Pramod Digambar | Buchunde, Pallavi | Vasudevan, Anil Kumar | Jena, Chinmay Kumar | Ghude, Sachin Dinkar | Dani, Kundan | Pandithurai, Govindan
The effect of relative humidity and temperature on the submicron aerosol variability and its ageing process was studied over a high altitude site, Mahabaleshwar in south-west India. The mass composition of non-refractory particulate matter of 1 μm (NR-PM₁) size was obtained using Time of Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) along with the measurements on a few trace gases during winter (December 2017–February 2018) and summer season (20th March - 5th May 2018). Sulfate exhibited strong dependence on the relative humidity (RH) as its mass fraction increased with the increase in RH. The Sulfate oxidation ratio (SOR) calculated during summer season also showed an increasing trend with RH indicating the influence of aqueous phase oxidation on sulfate fraction. On the other hand, OOA showed remarkable enhancement in its mass fraction with the increase in temperature along with the corresponding increase in f₄₄ and tropospheric ozone. OOA, ozone and f₄₄ ratio increased 14–34%, 8–26% and 25–43% respectively with the increase in temperature from 18 to 30 °C. This is indicative of the dominance of photochemical ageing processes during high temperature conditions. The extent of photochemical ageing was found to be higher during summer season (mean temperature ∼25.4 ± 2.6 °C) as compared to winter season (mean temperature ∼20.5 ± 2.6 °C). The nitrate diurnal was majorly governed by gas to particle partitioning process during winter season, whereas the summertime nitrate diurnal was influenced primarily by its formation rate. The non parametric wind regression analysis revealed that the mass concentration during winter was majorly contributed by distant sources from north east direction while during summer the local sources were more dominant.
Mostrar más [+] Menos [-]Weathered Mississippi Canyon 252 crude oil ingestion alters cytokine signaling, lowers heterophil:lymphocyte ratio, and induces sickness behavior in zebra finches (Taeniopygia guttata) Texto completo
2020
Goodchild, Christopher G. | Love, Ashley C. | Krall, Jeffrey B. | DuRant, Sarah E.
The Deepwater Horizon (DWH) oil spill caused an estimated 100,000 bird mortalities. However, mortality estimates are often based on the number of visibly oiled birds and likely underestimate the true damage to avian populations as they do not include toxic effects from crude oil ingestion. Elevated susceptibility to disease has been postulated to be a significant barrier to recovery for birds that have ingested crude oil. Effective defense against pathogens involves integration of physiological and behavioral traits, which are regulated in-part by cytokine signaling pathways. In this study, we tested whether crude oil ingestion altered behavioral and physiological aspects of disease defense in birds. To do so, we used artificially weathered Mississippi Canyon 242 crude oil to orally dose zebra finches (Taeniopygia guttata) with 3.3 mL/kg or 10 mL/kg of crude oil or a control (peanut oil) for 14 days. We measured expression of cytokines (interleukin [IL]-1β, IL-6, IL-10) and proinflammatory pathways (NF-κB, COX-2) in the intestine, liver, and spleen (tissues that exhibit pathology in oil-exposed birds). We also measured heterophil:lymphocyte (H:L) ratio and complement system activity, and video-recorded birds to analyze sickness behavior. Finches that ingested crude oil exhibited tissue-specific changes in cytokine mRNA expression. Proinflammatory cytokine expression decreased in the intestine but increased in the liver and spleen. Birds exposed to crude oil had lower H:L ratios compared to the control on day 14, but there were no differences in complement activity among treatments. Additionally, birds exposed to 10 mL/kg crude oil had reduced activity, indicative of sickness behavior. Our results suggest cytokines play a role in mediating physiological and behavioral responses to crude oil ingestion. Although most avian population damage assessments focus on mortality caused by external oiling, crude oil ingestion may also indirectly affect survival by altering physiological and behavioral traits important for disease defense.
Mostrar más [+] Menos [-]Influence of chemical aging on physico-chemical properties of mineral dust particles: A case study of 2016 dust storms over Delhi Texto completo
2020
Goel, Vikas | Mishra, Sumit K. | Pal, Prabir | Ahlawat, Ajit | Vijayan, Narayanasamy | Jain, Srishti | Sharma, C. (Chhemendra)
The physico-chemical properties of dust particles collected During Dust Storm (DDS) and After Dust Storm (ADS) events were studied using Scanning Electron Microscope coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Fluorescence Spectroscopy (XRF) and X-ray Photoelectron Spectroscopy (XPS). Morphological and compositional change in dust particles were observed as they react with the anthropogenic pollutants present in the urban environment. The calcite rich particles were observed to transform into calcium chloride, calcium nitrate, and calcium sulfate on reacting with the chlorides, nitrates, and sulfates present in the urban atmosphere. The frequency distributions of Aspect Ratio (AR) for the DDS and ADS particles were observed to be bimodal (mode peaks at 1.2 and 1.5) and monomodal (mode peak at 1.1), respectively. The highly irregular shaped solid dust particles were observed to transform into nearly spherical semisolid particles in the urban environment. XPS analysis confirms the high concentration of oxides, nitrates, and chlorides at the surface of ADS samples which show the signatures of mineral dust particles aging. Species with a high value of imaginary part of refractive index (like Cr metal, Fe metal, Cr₂O₃, FeO, Fe₂O₃) were observed at the surface of dust particles. At 550 nm wavelength, the light-absorbing potential of the observed species along with black carbon (BC) was found to vary in the order; Cr metal > Fe metal > Cr₂O₃> FeO > BC > Fe₂O₃> FeOOH. The presence of the aforementioned species on the surface of ADS particles will tremendously affect the particle optical and radiative properties compared to that of DDS particles. The present work could reduce the uncertainty in the radiation budget estimations of mineral dust and assessment of their climatic impacts over Delhi.
Mostrar más [+] Menos [-]Prenatal exposure to residential PM2.5 and anogenital distance in infants at birth: A birth cohort study from Shanghai, China Texto completo
2020
Sun, Xiaowei | Liu, Cong | Wang, Ziliang | Yang, Fen | Liang, Hong | Miao, Maohua | Yuan, Wei | Kan, Haidong
Fine particulate matter (PM₂.₅) is believed to be one of the most hazardous air pollution with a ubiquitous presence. Animal studies have reported the association between prenatal exposure to traffic pollutant (not exclusively including PM₂.₅) and reproductive development in male offspring. However, the effects of prenatal exposure to PM₂.₅ on reproductive health in children are still unknown. The present study was based on the Shanghai-Minhang Birth Cohort Study (S-MBCS). A total of 876 pregnant women and their infants were included. Infants’ anogenital distance (AGD, the distance from the anus to the genitals; AGDap [anus-penis] and AGDas [anus-scrotum] for boys, and AGDac [anus-clitoris] and AGDaf [anus-fourchette] for girls) were measured at birth. PM₂.₅ concentrations during pregnancy were estimated using satellite based modeling approach. Multiple linear regression analysis and multiple informant model were conducted to examine the associations between prenatal exposure to PM₂.₅ (pre μg/m³) and offspring’s AGDs (mm). In order to minimize the misclassification of exposure, a sensitivity analysis restricted to mothers being off work during pregnancy was performed. In multiple linear regression models, we found that prenatal exposure to PM₂.₅ during the 1ˢᵗ and 3ʳᵈ trimesters was associated with shorter AGDs. In multiple informant model, similar patterns were found, and statistically significant reductions were observed in AGDap (β=−0.278, 95%CI: -0.343∼-0.212), AGDac (β=−0.188, 95%CI: -0.247∼-0.130) and AGDaf (β= −0.163, 95%CI: -0.238∼-0.088) with PM₂.₅ exposure during the 1ˢᵗ trimester, and AGDap (β=−0.201, 95%CI: -0.247∼-0.155), AGDas (β=−0.158, 95%CI: -0.198∼-0.117), AGDac (β=−0.128, 95%CI: -0.167∼-0.089) and AGDaf (β = −0.144, 95%CI: -0.194∼-0.094) with PM₂.₅ exposure during the 3ʳᵈ trimester. The sensitivity analysis restricted to women being off work during pregnancy showed similar results. PM₂.₅ exposure during the 1ˢᵗ and 3ʳᵈ trimesters was associated with shortened AGDs in offspring at birth. Our findings provide preliminary evidence that prenatal exposure to PM₂.₅ might be associated with the reproductive development of offspring.
Mostrar más [+] Menos [-]Advanced determination of the spatial gradient of human health risk and ecological risk from exposure to As, Cu, Pb, and Zn in soils near the Ventanas Industrial Complex (Puchuncaví, Chile) Texto completo
2020
Tapia-Gatica, Jaime | González-Miranda, Isabel | Salgado, Eduardo | Bravo, Manuel A. | Tessini, Catherine | Dovletyarova, Elvira A. | Paltseva, Anna A. | Neaman, Alexander
The townships of Puchuncaví and Quintero, on the coast of central Chile, have soils contaminated by atmospheric deposition of sulfur dioxide and trace elements from the nearby Ventanas Industrial Complex. The purpose of this study was to evaluate potential human health and ecological risks, by determining the spatial distribution of soil total concentrations arsenic (As), copper (Cu), lead (Pb), and zinc (Zn) in these townships. Total concentrations of these elements were determined in 245 topsoil samples, used to generate continuous distribution maps. The background concentrations of Cu, As, Pb, and Zn in the studied soils were 100, 16, 35, and 122 mg kg⁻¹, respectively. The concentrations of Cu, As, and Pb were positively correlated with each other, suggesting that their source is the Ventanas copper smelter. On the other hand, correlations for Zn were weaker than for other trace elements, suggesting low impact of the Ventanas copper smelter on spatial distribution of Zn. Indeed, only 6% of the study area exhibited Zn concentrations above the background level. In contrast, 77, 32 and 35% of the study area presented Cu, As, and Pb concentrations, respectively, above the background level. The carcinogenic risk due to exposure to As was above the threshold value of 10⁻⁰⁴ in the population of young children (1–5 years old) on 27% of the study area. These risk values are classified as unacceptable, which require specific intervention by the Chilean government. Based on the estimated concentrations of exchangeable Cu, 10, 15, and 75% of the study area exhibited high, medium, and low phytotoxicity risk, respectively.
Mostrar más [+] Menos [-]Effects of ambient particulate matter on fasting blood glucose: A systematic review and meta-analysis Texto completo
2020
Ma, Runmei | Zhang, Yi | Sun, Zhiying | Xu, Dandan | Li, Tiantian
Studies have found that ambient particulate matter (PM) affects fasting blood glucose. However, the results are not consistent. We conducted a systematic review and meta-analysis to determine the relationship between PM with an aerodynamic diameter of 10 μm or less (PM₁₀) and PM with an aerodynamic diameter of 2.5 μm or less (PM₂.₅) and fasting blood glucose. We searched PubMed, Web of Science, the Wanfang Database and the China National Knowledge Infrastructure up to April 1, 2019. A total of 24 papers were included in the review, and 17 studies with complete or convertible quantitative information were included in the meta-analysis. The studies were divided into groups by PM size fractions (PM₁₀ and PM₂.₅) and length of exposure. Long-term exposures were based on annual average concentrations, and short-term exposures were those lasting less than 28 days. In the long-term exposure group, fasting blood glucose increased 0.10 mmol/L (95% CI: 0.02, 0.17) per 10 μg/m³ of increased PM₁₀ and 0.23 mmol/L (95% CI: 0.01, 0.45) per 10 μg/m³ of increased PM₂.₅. In the short-term exposure group, fasting blood glucose increased 0.02 mmol/L (95% CI: −0.01, 0.04) per 10 μg/m³ of increased PM₁₀ and 0.08 mmol/L (95% CI: 0.04, 0.11) per 10 μg/m³ of increased PM₂.₅. Further prospective studies are needed to explore the relationship between ambient PM exposure and fasting blood glucose.
Mostrar más [+] Menos [-]