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Resultados 3271-3280 de 4,308
Effect of acute exposure to PFOA on mouse liver cells in vivo and in vitro Texto completo
2017
Wu, Xinmou | Liang, Minqing | Yang, Zhao | Su, Min | Yang, Bin
Increasingly, epidemiological evidences indicate chemosynthetic perfluorooctanoic acid (PFOA), an environmental pollutant, induces potential adverse effect on human health after long-term exposure. However, less study has been performed for assessment of acute effect of PFOA exposure on metabolic homeostasis. In experimental designs, PFOA-exposed liver cells in vivo and in vitro were used to discuss underlying mechanism related to PFOA-induced metabolic dysfunction. In serological tests, PFOA-exposed mice showed increased treads of liver functional enzymes in alanine transaminase (ALT), aspartate transaminase (AST), and total bilirubin (T-BIL), trypsinase, low density lipoprotein-cholesterol (LDL-C), and insulin, while blood glucose, high density lipoprotein-cholesterol (HDL-C), and glucagon levels were reduced. In histocytological observations, PFOA-exposed liver showed visible cytoplasmic vesicles, and intact pancreatic islets were observed in PFOA-exposed pancreas. Additionally, increased insulin-positive cells and reduced glucagon-positive cells were detected in PFOA-exposed islets. As shown in immunoassays, PFOA-exposed liver resulted in elevations of cluster of differentiation 36 (CD36)-labeled cells and CD36 protein. In mouse liver cell study, PFOA-exposed cells showed increased cell apoptotic count, and increased phosphorylated levels of Bcl-2 and Bad in the cells. Furthermore, PFOA-exposed liver cells exhibited elevations of CD36-labeled cells and CD36 protein. Taken together, the present data demonstrate that acute exposure to PFOA-impaired liver function is associated with inducting CD36 expression and apoptosis, as well as disrupting key hormones in the pancreas.
Mostrar más [+] Menos [-]Removal of Anabaena spiroides by potassium permanganate pre-oxidation: effect on photosynthetic capacity and molecular weight distribution Texto completo
2017
Qiao, Junlian | Zhang, Xiaodong | Lv, Liping
Bench scale tests were conducted to investigate the effect of potassium permanganate pre-oxidation on the photosynthetic activity and molecular weight distribution of Anabaena spiroides. Different concentrations of potassium permanganate were added into the suspension of Anabaena spiroides, one of the dominant algae in water bloom, and after pre-oxidation of permanganate for 1 h, the results show that the removal rate significantly increases by 33.99~36.35% compared to direct coagulation. Then, the algal characteristics, including photosynthetic ability, the changes in extracellular organic matter three-dimensional fluorescence, and the distribution of molecular weight were conducted and the results show that along with increasing concentration of potassium permanganate, the photosynthetic ability of algae decreases, more extracellular organic matter is secreted, and large molecular weight matter (humic-like and fulvic-like substances) are generated. Therefore, this study demonstrates that potassium permanganate could be used in addressing the algae-rich water.
Mostrar más [+] Menos [-]Effects of portable solar water quality control machines on aquaculture ponds Texto completo
2017
Liu, Xingguo | Xu, Hao | Cheng, Guofeng | Liu, Chong | Liu, Shijing | Lu, Shimin | Tian, Changfeng | Tang, Rong | Gu, Zhaojun
The effects of a portable solar water quality control machine (PSWM) on water quality and sediment of aquaculture ponds were studied in bream aquaculture ponds in Shanghai, China. PSWM operation reduced the temperature and dissolved oxygen (DO) differences between upper and lower water levels. Concentrations of NH₄ ⁺-N, NO₂ ⁻-N, TN, TP, COD and TSS increased rapidly and reached maximums at 12 h. The density and biomass of phytoplankton and levels of chlorophyll a reached maximums after 40 h of PSWM operation. In a 165-day study, the mean concentrations of NH₄ ⁺-N, NO₂ ⁻-N and the available phosphorous (AP) in the PSWM ponds were significantly lower than in the control ponds, but the TP was significantly greater than the control ponds. Compared with the test began, the thickness of the sediment in PSWM ponds declined by 12.4 ± 4.3 cm, the control ponds increased by 5.0 ± 2.3 cm and the TN and AP levels in sediment significantly declined. PSWM treatment increased the production of bream and silver carp by 30 and 25%, respectively, and the feed coefficient was reduced by 24.2%. Use of PSWM in bream aquaculture ponds improved water quality, reduced sediment, reduced aquaculture pollution emissions and increased production.
Mostrar más [+] Menos [-]Historical and future emission of hazardous air pollutants (HAPs) from gas-fired combustion in Beijing, China Texto completo
2017
Xue, Yifeng | Nie, Lei | Zhou, Zhen | Tian, Hezhong | Yan, Jing | Wu, Xiaoqing | Cheng, Linglong
The consumption of natural gas in Beijing has increased in the past decade due to energy structure adjustments and air pollution abatement. In this study, an integrated emission inventory of hazardous air pollutants (HAPs) emitted from gas-fired combustion in Beijing was developed for the period from 2000 to 2014 using a technology-based approach. Future emission trends were projected through 2030 based on current energy-related and emission control policies. We found that emissions of primary HAPs exhibited an increasing trend with the rapid increase in natural gas consumption. Our estimates indicated that the total emissions of NO X , particulate matter (PM)₁₀, PM₂.₅, CO, VOCs, SO₂, black carbon, Pb, Cd, Hg, As, Cr, Cu, Ni, Zn, polychlorinated dibenzo-p-dioxins and dibenzofurans, and benzo[a]pyrene from gas-fired combustion in Beijing were approximately 22,422 t, 1042 t, 781 t, 19,097 t, 653 t, 82 t, 19 t, 0.6 kg, 0.1 kg, 43 kg, 52 kg, 0.3 kg, 0.03 kg, 4.3 kg, 0.6 kg, 216 μg, and 242 g, respectively, in 2014. To mitigate the associated air pollution and health risks caused by gas-fired combustion, stricter emission standards must be established. Additionally, combustion optimization and flue gas purification system could be used for lowering NO X emissions from gas-fired combustion, and gas-fired facilities should be continuously monitored based on emission limits. Graphical abstract Spatial distribution and typical live photos of gas-fired boiler in Beijing
Mostrar más [+] Menos [-]Spatial analysis and health risk assessment of heavy metals concentration in drinking water resources Texto completo
2017
Fallahzadeh, Reza Ali | Ghaneian, Mohammad Taghi | Miri, Mohammad | Dashti, Mohamad Mehdi
The heavy metals available in drinking water can be considered as a threat to human health. Oncogenic risk of such metals is proven in several studies. Present study aimed to investigate concentration of the heavy metals including As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn in 39 water supply wells and 5 water reservoirs within the cities Ardakan, Meibod, Abarkouh, Bafgh, and Bahabad. The spatial distribution of the concentration was carried out by the software ArcGIS. Such simulations as non-carcinogenic hazard and lifetime cancer risk were conducted for lead and nickel using Monte Carlo technique. The sensitivity analysis was carried out to find the most important and effective parameters on risk assessment. The results indicated that concentration of all metals in 39 wells (except iron in 3 cases) reached the levels mentioned in EPA, World Health Organization, and Pollution Control Department standards. Based on the spatial distribution results at all studied regions, the highest concentrations of metals were derived, respectively, for iron and zinc. Calculated HQ values for non-carcinogenic hazard indicated a reasonable risk. Average lifetime cancer risks for the lead in Ardakan and nickel in Meibod and Bahabad were shown to be 1.09 × 10⁻³, 1.67 × 10⁻¹, and 2 × 10⁻¹, respectively, demonstrating high carcinogenic risk compared to similar standards and studies. The sensitivity analysis suggests high impact of concentration and BW in carcinogenic risk.
Mostrar más [+] Menos [-]Investigation of cis-trans isomer dependent dermatotoxicokinetics of UV filter ethylhexyl methoxycinnamate through stratum corneum in vivo Texto completo
2017
Sharma, Anežka | Bányiová, Katarína | Vrana, Branislav | Justan, Ivan | Čupr, Pavel
2-Ethylhexyl methoxycinnamate (EHMC) is one of the most used ultraviolet filters in personal care products. It undergoes cis/trans isomerization in sunlight, and there is limited toxicological understanding of the effects of the cis-isomer. It is known that two geometric isomers of one compound can have different physico-chemical properties and effects. However, there are no studies focusing on toxicokinetics of EHMC isomerization products to compare their potential difference in dermal exposure to cis-EHMC and trans-EHMC due to the difference in their dermatotoxicokinetics. In this study, dermal absorption of the parental trans-EHMC and its cis isomer was studied. A commercially available sunscreen lotion containing trans-EHMC and spiked with laboratory-prepared cis-EHMC was locally applied on the forearm skin of two volunteers. After 8 h of skin exposure, the stratum corneum (SC) layer was removed by tape stripping. The removed thickness of the SC was determined spectrophotometrically using a total protein assay. The concentration of both isomers in the removed SC was measured by HPLC-DAD. A new diffusion and permeability coefficient of both EHMC isomers in SC were determined by Fick’s second law of diffusion in vivo. The difference in dermatotoxicokinetic parameters between the two isomers was not statistically significant. However, separate toxicological studies of isomeric forms and the determination of their dermatotoxicokinetic parameters are crucial for refinement of human risk assessment.
Mostrar más [+] Menos [-]A socio-scientific analysis of the environmental and health benefits as well as potential risks of cassava production and consumption Texto completo
2017
Mombo, S. | Dumat, C. | Moshtaghzadeh, Majid | Schreck, E.
Due to its high adaptability, cassava (Manihot esculenta Crantz) is one of the world’s most cultivated and consumed plants after maize and rice. However, there are relatively few scientific studies on this important crop. The objective of this review was therefore to summarize and discuss the available information on cassava cropping in order to promote sustainable practices in terms of production and consumption. Cassava cultivation has been expanding recently at the global scale and is widely consumed in most regions of South America, Africa, and Asia. However, it is also characterized by the presence in its roots of potentially toxic hydrocyanic acid. Furthermore, cassava can also absorb pollutants as it is currently cultivated near roads or factories and generally without consideration for potential sources of soil, water, or atmospheric pollution. Careful washing, peeling, and adequate preparation before eating are therefore crucial steps for reducing human exposure to both environmental pollutants and natural hydrocyanic acid. At present, there is not enough precise data available on this staple food crop. To improve our knowledge on the nutritive benefits versus health risks associated with cassava consumption, further research is necessary to compare cassava cultivars and precisely study the influence of preparation methods.
Mostrar más [+] Menos [-]Benzo(a)pyrene degradation and microbial community responses in composted soil Texto completo
2017
Zhu, Fengxiao | Storey, Sean | Ashaari, Mardiana Mohd | Clipson, Nicholas | Doyle, Evelyn
Benzo(a)pyrene degradation was compared in soil that was either composted, incubated at a constant temperature of 22 °C, or incubated under a temperature regime typical of a composting process. After 84 days, significantly more (61%) benzo(a)pyrene was removed from composted soil compared to soils incubated at a constant temperature (29%) or at composting temperatures (46%). Molecular fingerprinting approaches indicated that in composted soils, bacterial community changes were driven by both temperature and organic amendment, while fungal community changes were primarily driven by temperature. Next-generation sequencing data revealed that the bacterial community in composted soil was dominated by Actinobacteria (order Actinomycetales), Firmicutes (class Bacilli), and Proteobacteria (classes Gammaproteobacteria and Alphaproteobacteria), regardless of whether benzo(a)pyrene was present or not. The relative abundance of unclassified Actinomycetales (Actinobacteria) was significantly higher in composted soil when degradation was occurring, indicating a potential role for these organisms in benzo(a)pyrene metabolism. This study provides baseline data for employing straw-based composting strategies for the removal of high molecular weight PAHs from soil and contributes to the knowledge of how microbial communities respond to incubation conditions and pollutant degradation.
Mostrar más [+] Menos [-]Comparison of soil heavy metal pollution caused by e-waste recycling activities and traditional industrial operations Texto completo
2017
He, Kailing | Sun, Zehang | Hu, Yuanan | Zeng, Xiangying | Yu, Zhiqiang | Cheng, Hefa
The traditional industrial operations are well recognized as an important source of heavy metal pollution, while that caused by the e-waste recycling activities, which have sprouted in some developing countries, is often overlooked. This study was carried out to compare the status of soil heavy metal pollution caused by the traditional industrial operations and the e-waste recycling activities in the Pearl River Delta, and assess whether greater attention should be paid to control the pollution arising from e-waste recycling activities. Both the total contents and the chemical fractionation of major heavy metals (As, Cr, Cd, Ni, Pb, Cu, and Zn) in 50 surface soil samples collected from the e-waste recycling areas and 20 soil samples from the traditional industrial zones were determined. The results show that the soils in the e-waste recycling areas were mainly polluted by Cu, Zn, As, and Cd, while Cu, Zn, As, Cd, and Pb were the major heavy metals in the soils from the traditional industrial zones. Statistical analyses consistently show that Cu, Cd, Pb, and Zn in the surface soils from both types of sites were contributed mostly by human activities, while As, Cr, and Ni in the soils were dominated by natural background. No clear distinction was found on the pollution characteristic of heavy metals in the surface soils between the e-waste recycling areas and traditional industrial zones. The potential ecological risk posed by heavy metals in the surface soils from both types of sites, which was dominated by that from Cd, ranged from low to moderate. Given the much shorter development history of e-waste recycling and its largely unregulated nature, significant efforts should be made to crack down on illegal e-waste recycling and strengthen pollution control for related activities.
Mostrar más [+] Menos [-]Influence of crude oil exposure on cardiac function and thermal tolerance of juvenile rainbow trout and European sea bass Texto completo
2017
Anttila, Katja | Mauduit, Florian | Le Floch, Stéphane | Claireaux, Guy | Nikinmaa, Mikko
Influence of crude oil exposure on cardiac function and thermal tolerance of juvenile rainbow trout and European sea bass Texto completo
2017
Anttila, Katja | Mauduit, Florian | Le Floch, Stéphane | Claireaux, Guy | Nikinmaa, Mikko
Oil spills pose a threat to aquatic organisms. However, the physiological effects of crude oil on cardiac function and on thermal tolerance of juvenile fish are still poorly understood. Consequently, in this paper, we will present results of two separate experiments where we exposed juvenile rainbow trout and European sea bass to crude oil and made cardiac thermal tolerances and maximum heart rate (f Hₘₐₓ) measurements after 1 week (rainbow trout) and 6-month recovery (sea bass). In both species, the f Hₘₐₓ was lower in crude oil-exposed fish than in the control ones at temperatures below the optimum but this difference disappeared at higher temperatures. More importantly, the oil-exposed fish had significantly higher Arrhenius break point temperature for f Hₘₐₓ, which gave an estimate for optimum temperature, than the control fish in both species even though the exposure conditions and recovery times differed between species. The results indicated that exposure of juvenile fish to crude oil did not have a significant negative impact upon their cardiac performance in high temperatures and upper thermal tolerance increased when the fish were tested 1 week or 6 months after the exposure. Our findings suggest that the cardiac function and thermal tolerance of juvenile fish are relatively resistant to a crude oil exposure.
Mostrar más [+] Menos [-]Influence of crude oil exposure on cardiac function and thermal tolerance of juvenile rainbow trout and European sea bass Texto completo
2017
Anttila, Katja | Mauduit, Florian | Le Floch, Stephane | Claireaux, Guy | Nikinmaa, Mikko
Oil spills pose a threat to aquatic organisms. However, the physiological effects of crude oil on cardiac function and on thermal tolerance of juvenile fish are still poorly understood. Consequently, in this paper, we will present results of two separate experiments where we exposed juvenile rainbow trout and European sea bass to crude oil and made cardiac thermal tolerances and maximum heart rate (fHmax) measurements after 1 week (rainbow trout) and 6-month recovery (sea bass). In both species, the fHmax was lower in crude oil-exposed fish than in the control ones at temperatures below the optimum but this difference disappeared at higher temperatures. More importantly, the oil-exposed fish had significantly higher Arrhenius break point temperature for fHmax, which gave an estimate for optimum temperature, than the control fish in both species even though the exposure conditions and recovery times differed between species. The results indicated that exposure of juvenile fish to crude oil did not have a significant negative impact upon their cardiac performance in high temperatures and upper thermal tolerance increased when the fish were tested 1 week or 6 months after the exposure. Our findings suggest that the cardiac function and thermal tolerance of juvenile fish are relatively resistant to a crude oil exposure.
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