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1.
2.
Increasing levels of Heracleum persicum (golpar) in drinking water were studied in broilers. Two hundred and forty-one-day-old male chickens were allocated to one of six treatments: control, without added phytogenics nor probiotics in drinking water, and probiotics at recommended manufacturer’s level (P) or 1.0, 1.5, 2.0, and 2.5 ml/l of golpar extract solution (G1, G1.5, G2, and G2.5 treatments, respectively) in drinking water. As a result of this study, no linear or quadratic trends in the feed intake (FI) and feed conversion rate (FCR) due to golpar supplementation were found. Body weight gain, final body weight, and relative carcass weight showed a positive linear response with increasing levels of golpar supplementation. Neither golpar nor probiotics had effects on the percentages of edible parts of the carcass. Golpar supplementation levels caused a linear negative response of the albumin content in blood plasma, whereas both abdominal fat as percentage of carcass weight and uric acid levels in blood plasma linearly increased. The effects on Ig responses were only observed at 42 days of age and were similar in probiotics and the highest level of golpar supplementation. Based on our results, both probiotics and golpar supplementation could improve broiler performance and immune function.  相似文献   

3.
We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.  相似文献   

4.
Considering the increasing incorporation of manufactured nano-material into consumer products, there is a concern about its potential impacts in biological wastewater treatment. In this study, the response of anaerobic sludge to the presence of Bi2WO6 nano-particles (NPs) was investigated in the anaerobic membrane bioreactor (AnMBR). As the concentration of Bi2WO6 in the reactor was controlled around 1 mg/L, there was no significant difference in effluent water quality or bacterial activities before and after NP exposure, partially due to the microbial-induced NP aggregation and stable complex formation. However, with the increasing dosage of Bi2WO6 from 5 to 40 mg/L, great influences on the AnMBR performance were observed, including the reduction of COD removal efficiency, inhibition of the mechanization step, increased production of soluble microbial products, and enhanced secretion of extracellular polymer substrates. Additional investigation with high-throughput sequencing was conducted, clearly demonstrating that Bi2WO6 NPs induced changes in the bacterial community.  相似文献   

5.
It has been shown that manganese dioxide (MnO2) can mediate transformation of phenolic contaminants to form phenoxyl radical intermediates, and subsequently, these intermediates intercouple to form oligomers via covalent binding. However, the reaction kinetics and transformation mechanisms of phenolic contaminants with humic molecules present in nano-MnO2-mediated systems were still unclear. In this study, it was proven that nano-MnO2 were effective in transforming triclosan under acidic conditions (pH 3.5–5.0) during manganese reduction, and the apparent pseudo first-order kinetics rate constants (k?=?0.0599–1.5314 h?1) increased as the pH decreased. In particular, the transformation of triclosan by nano-MnO2 was enhanced in the presence of low-concentration humic acid (1–10 mg L?1). The variation in the absorption of humic molecules at 275 nm supported possible covalent binding between humic molecules and triclosan in the nano-MnO2-mediated systems. A total of four main intermediate products were identified by high-resolution mass spectrometry (HRMS), regardless of humic molecules present in the systems or not. These products correspond to a suite of radical intercoupling reactions (dimers and trimers), ether cleavage (2,4-dichlorophenol), and oxidation to quinone-like products, triggered by electron transfer from triclosan molecules to nano-MnO2. A possible reaction pathway in humic acid solutions, including homo-coupling, decomposition, oxidation, and cross-coupling, was proposed. Our findings provide valuable information regarding the environmental fate and transformation mechanism of triclosan by nano-MnO2 in complex water matrices.  相似文献   

6.
Abstract

We evaluated day-of-week differences in mean concentrations of ozone (O3) precursors (nitric oxide [NO], nitrogen oxides [NOx], carbon moNOxide [CO], and volatile organic compounds [VOCs]) at monitoring sites in 23 states comprising seven geographic focus areas over the period 1998– 2003. Data for VOC measurements were available for six metropolitan areas in five regions. We used Wednesdays to represent weekdays and Sundays to represent weekends; we also analyzed Saturdays. At many sites, NO, NOx, and CO mean concentrations decreased at all individual hours from 6:00 a.m. to 3:00 p.m. on Sundays compared with corresponding Wednesday means. Statistically significant (p < 0.01) weekend decreases in ambient concentrations were observed for 92% of NOx sites, 89% of CO sites, and 23% of VOC sites. Nine-hour (6:00 a.m. to 3:00 p.m.) mean concentrations of NO, NOx, CO, and VOCs declined by 65, 49, 28, and 19%, respectively, from Wednesdays to Sundays (median site responses). Despite the large reductions in ambient NOx and moderate reductions in ambient CO and VOC concentrations on weekends, ozone and particulate matter (PM) nitrate did not exhibit large changes from week-days to weekends. The median differences between Wednesday and Sunday mean ozone concentrations at all monitoring sites ranged from 3% higher on Sundays for peak 8-hr concentrations determined from all monitoring days to 3.8% lower on Sundays for peak 1-hr concentrations on extreme-ozone days. Eighty-three percent of the sites did not show statistically significant differences between Wednesday and weekend mean concentrations of peak ozone. Statistically significant weekend ozone decreases occurred at 6% of the sites and significant increases occurred at 11% of the sites. Average PM nitrate concentrations were 2.6% lower on Sundays than on Wednesdays. Statistically significant Sunday PM nitrate decreases occurred at one site and significant increases occurred at seven sites.  相似文献   

7.
The provision of ecosystem services is a prominent rationale for urban greening, and there is a prevailing mantra that ‘trees are good’. However, understanding how urban trees contribute to sustainability must also consider disservices. In this perspective article, we discuss recent research on ecosystem disservices of urban trees, including infrastructure conflicts, health and safety impacts, aesthetic issues, and environmentally detrimental consequences, as well as management costs related to ecological disturbances and risk management. We also discuss tradeoffs regarding species selection and local conservation concerns, as well as the central role of human perception in the interpretation of ecosystem services and disservices, particularly the uncritical assertion that ‘everybody loves trees’. Urban forestry decision-making that fails to account for disservices can have unintended negative consequences for communities. Further research is needed regarding life cycle assessments, stakeholder decision-making, return-on-investment, and framings of services and disservices in urban forestry.  相似文献   

8.
Two types of zeolites—natural clinoptilolite (NZ) and synthetic zeolite A (A)—were enriched with approx. 0.25 mmol of Cu(II), Zn(II), or Ag(I) ions, and the obtained materials (M-Z) were tested against three different isolates of Escherichia coli. Two isolates were environmental isolates from waters in Serbia whereas the third one was DSM 498. Antibacterial activity was studied in different water media—nutrient-rich media (peptone water), water from Sava Lake, and commercially available spring water. The Ag-containing zeolites showed bactericidal activity in the nutrient-rich peptone water after 1 h of contact. Cu- and Zn-containing zeolites showed bactericidal activity in real water samples. Antibacterial activity of the M-Z decreases in all three examined water media in the following order: Ag-NZ ≈ Ag-A > Cu-NZ ≈ Cu-A > Zn-NZ >>> Zn-A, suggesting that mainly the metal type and not the zeolite type have a role in the antibacterial activity. Leaching experiments showed small amounts of the leached Cu(II) and Zn(II) ions, indicating that the antibacterial activity is not due to the metal ions but should be attributed to the M-Z itself. However, leached amounts of Ag(I) from Ag-NZ and Ag-A in peptone water indicate that the released Ag(I) could be mainly responsible for the bactericidal effect of the Ag(I)-containing zeolites. Since no loss of cellular material was found, the antibacterial activity is not attributed to cytoplasmic membrane damage.  相似文献   

9.
The present study investigated the comprehensive chemical composition [organic carbon (OC), elemental carbon (EC), water-soluble inorganic ionic components (WSICs), and major & trace elements] of particulate matter (PM2.5) and scrutinized their emission sources for urban region of Delhi. The 135 PM2.5 samples were collected from January 2013 to December 2014 and analyzed for chemical constituents for source apportionment study. The average concentration of PM2.5 was recorded as 121.9 ± 93.2 μg m?3 (range 25.1–429.8 μg m?3), whereas the total concentration of trace elements (Na, Ca, Mg, Al, S, Cl, K, Cr, Si, Ti, As, Br, Pb, Fe, Zn, and Mn) was accounted for ~17% of PM2.5. Strong seasonal variation was observed in PM2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon seasons. The chemical composition of the PM2.5 was reconstructed using IMPROVE equation, which was observed to be in good agreement with the gravimetric mass. Source apportionment of PM2.5 was carried out using the following three different receptor models: principal component analysis with absolute principal component scores (PCA/APCS), which identified five major sources; UNMIX which identified four major sources; and positive matrix factorization (PMF), which explored seven major sources. The applied models were able to identify the major sources contributing to the PM2.5 and re-confirmed that secondary aerosols (SAs), soil/road dust (SD), vehicular emissions (VEs), biomass burning (BB), fossil fuel combustion (FFC), and industrial emission (IE) were dominant contributors to PM2.5 in Delhi. The influences of local and regional sources were also explored using 5-day backward air mass trajectory analysis, cluster analysis, and potential source contribution function (PSCF). Cluster and PSCF results indicated that local as well as long-transported PM2.5 from the north-west India and Pakistan were mostly pertinent.  相似文献   

10.
Natural and human activities generate a significant amount of PM2.5 (particles ≤2.5 μm in aerodynamic diameter) into the surrounding atmospheric environments. Because of their small size, they can remain suspended for a relatively longer time in the air than coarse particles and thus can travel long distances in the atmosphere. PM2.5 is one of the key indicators of pollution and known to cause numerous types of respiratory and lung-related diseases. Due to poor implementation of regulations and a time lag in introducing the vehicle technology, levels of PM2.5 in most Asian cities are much worse than those in European environments. Dedicated reviews on understanding the characteristics of PM2.5 in Asian urban environments are currently missing but much needed. In order to fill the existing gaps in the literature, the aim of this review article is to describe dominating sources and their classification, followed by current status and health impact of PM2.5, in Asian countries. Further objectives include a critical synthesis of the topics such as secondary and tertiary aerosol formation, chemical composition, monitoring and modelling methods, source apportionment, emissions and exposure impacts. The review concludes with the synthesis of regulatory guidelines and future perspectives for PM2.5 in Asian countries. A critical synthesis of literature suggests a lack of exposure and monitoring studies to inform personal exposure in the household and rural areas of Asian environments.  相似文献   

11.
BACKGROUND, AIM AND SCOPE: Pollution-induced endocrine disruption in vertebrates and invertebrates is a worldwide environmental problem, but relatively little is known about effects of endocrine disrupting compounds (EDCs) in planktonic crustaceans (including Daphnia magna). Aims of the present study were to investigate acute 48 h toxicity and sub-chronic (4-6 days) and chronic (21 days) effects of selected EDCs in D. magna. We have investigated both traditional endpoints as well as other parameters such as sex determination, maturation, molting or embryogenesis in order to evaluate the sensitivity and possible use of these endpoints in ecological risk assessment. MATERIALS AND METHODS: We have studied effects of four model EDCs (vinclozolin, flutamide, ketoconazole and dicofol) on D. magna using (i) an acute 48 h immobilization assay, (ii) a sub-chronic, 4-6 day assay evaluating development and the sex ratio of neonates, and (iii) a chronic, 21 day assay studying number of neonates, sex of neonates, molting frequency, day of maturation and the growth of maternal organisms. RESULTS: Acute EC50 values in the 48 h immobilization test were as follows (mg/L): dicofol 0.2, ketoconazole 1.5, flutamide 2.7, vinclozolin >3. Short-term, 4-6 day assays with sublethal concentrations showed that the sex ratio in Daphnia was modulated by vinclozolin (decreased number of neonate males at 1 mg/L) and dicofol (increase in males at 0.1 mg/L). Flutamide (up to 1 mg/L) had no effect on the sex of neonates, but inhibited embryonic development at certain stages during chronic assay, resulting in abortions. Ketoconazole had no significant effects on the studied processes up to 1 mg/L. DISCUSSION: Sex ratio modulations by some chemicals (vinclozolin and dicofol) corresponded to the known action of these compounds in vertebrates (i.e. anti-androgenicity and anti-oestrogenicity, respectively). Our study revealed that some chemicals known to affect steroid-regulated processes in vertebrates can also affect sublethal endpoints (e.g. embryonic sex determination and/or reproduction) in invertebrates such as D. magna. CONCLUSIONS: A series of model vertebrate endocrine disrupters affected various sub-chronic and chronic parameters in D. magna including several endpoints that have not been previously studied in detail (such as sex determination in neonates, embryogenesis, molting and maturation). Evaluations of traditional reproduction parameters (obtained from the 21 day chronic assay). as well as the results from a rapid, 4-6 day, sub-chronic assay provide complementary information on non-lethal effects of suspected organic endocrine disrupters. RECOMMENDATIONS AND PERSPECTIVES: It seems that there are analogies between vertebrates and invertebrates in toxicity mechanisms and in vivo effects of endocrine disruptors. However, general physiological status of organisms may also indirectly affect endpoints that are traditionally considered 'hormone regulated' (especially at higher effective concentrations as observed in this study) and these factors should be carefully considered. Further research of D. magna physiology and comparative studies with various EDCs will help to understand mechanisms of action as well as ecological risks of EDCs in the environment.  相似文献   

12.
Pharmaceuticals and personal care products (PPCPs) have attracted increasing concern during the last decade because of their widespread uses and continuous release to the aquatic environment. This work aimed to study the distribution of caffeine (CAF), oxybenzone (MBPh), and triclosan (TCS) when they arrive in salt marsh areas and to assess their remediation potential by two different species of salt marsh plants: Spartina maritima and Halimione portulacoides. Experiments were carried out in the laboratory either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, for 10 days. Controls without plants were also carried out. CAF, MBPh, and TCS were added to the media. In unvegetated sediment soaked in elutriate, CAF was mainly in the liquid phase (83%), whereas MBPh and TCS were in the solid phase (90% and 56%, respectively); the highest remediation was achieved for TCS (40%) and mainly attributed to bioremediation. The presence of plants in sediment soaked in elutriate-enhanced PPCPs remediation, decreasing CAF and TCS levels between approximately 20-30% and MBPh by 40%.. Plant uptake, adsorption to plant roots/sediments, and bio/rhizoremediation are strong hypothesis to explain the decrease of contaminants either in water or sediment fractions, according to PPCPs characteristics.  相似文献   

13.
Sood A  Uniyal PL  Prasanna R  Ahluwalia AS 《Ambio》2012,41(2):122-137
Aquatic macrophytes play an important role in the structural and functional aspects of aquatic ecosystems by altering water movement regimes, providing shelter to fish and aquatic invertebrates, serving as a food source, and altering water quality by regulating oxygen balance, nutrient cycles, and accumulating heavy metals. The ability to hyperaccumulate heavy metals makes them interesting research candidates, especially for the treatment of industrial effluents and sewage waste water. The use of aquatic macrophytes, such as Azolla with hyper accumulating ability is known to be an environmentally friendly option to restore polluted aquatic resources. The present review highlights the phytoaccumulation potential of macrophytes with emphasis on utilization of Azolla as a promising candidate for phytoremediation. The impact of uptake of heavy metals on morphology and metabolic processes of Azolla has also been discussed for a better understanding and utilization of this symbiotic association in the field of phytoremediation.  相似文献   

14.
Although the toxicological impact of metal oxide nanoparticles has been studied for the last few decades on aquatic organisms, the exact mechanism of action is still unclear. The fate, behavior, and biological activity of nanoparticles are dependent on physicochemical factors like size, shape, surface area, and stability in the medium. This study deals with the effect of nano and bulk CeO2 particles on marine microcrustacean, Artemia salina. The primary size was found to be 15 ± 3.5 and 582 ± 50 nm for nano and bulk CeO2 (TEM), respectively. The colloidal stability and sedimentation assays showed rapid aggregation of bulk particles in seawater. Both the sizes of CeO2 particles inhibited the hatching rate of brine shrimp cyst. Nano CeO2 was found to be more toxic to A. salina (48 h LC50 38.0 mg/L) when compared to bulk CeO2 (48 h LC50 92.2 mg/L). Nano CeO2-treated A. salina showed higher oxidative stress (ROS) than those treated with the bulk form. The reduction in the antioxidant activity indicated an increase in oxidative stress in the cells. Higher acetylcholinesterase activity (AChE) was observed upon exposure to nano and bulk CeO2 particles. The uptake and accumulation of CeO2 particles were increased with respect to the concentration and particle size. Thus, the above results revealed that nano CeO2 was more lethal to A. salina as compared to bulk particles.  相似文献   

15.
A gas chromatographic method for the determination of the insecticides acephate, dimethoate, methamidophos and omethoate in small amounts of nectar has been developed. By the use of a miniaturized extraction technique and a nitrogenphosphorus selective detector (NPD) residues down to 0.005 – 0.01 ppm could be detected in a sample size of 1 g. Because of the low content of co-extractives in nectar and the use of a highly selective detector a clean-up of the extracts was not necessary.  相似文献   

16.

Purpose  

Besides classical organic pollutants and pesticides, pharmaceuticals and their residues have nowadays become recognized as relevant environmental contaminants. The risks of these chemicals for aquatic ecosystems are well known, but information about the pharmaca-plant interactions and metabolic pathways is scarce. Therefore, we investigate the process of uptake of acetaminophen (N-Acetyl-4-aminophenol) by Brassica juncea, drug-induced defense responses and detoxification mechanisms in different plant parts.  相似文献   

17.
A greater understanding of gendered roles in fisheries is necessary to value the often-hidden roles that women play in fisheries and households. We examine women’s contributions to household food and income using focus group discussions, market surveys, and landings data in six communities in Timor-Leste. Women were actively fishing more days per month than men. Gleaning was the most frequent activity and 100% of trips returned with catch for food and/or income. Mollusc and crab catches were common and exploitation appeared targeted on a dynamic reappraisal of changing food values and changing estimates of group needs. With as many as 80% of households in coastal areas involved in fishing, and at least 50% of women fishing, this highlights the current lack of women’s engagement as a critical gap in fisheries management approaches. The current androcentric dialogue limits social-ecological understanding of these systems and the potential for their effective stewardship.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01335-7) contains supplementary material, which is available to authorized users.  相似文献   

18.
Relational thinking has recently gained increasing prominence across academic disciplines in an attempt to understand complex phenomena in terms of constitutive processes and relations. Interdisciplinary fields of study, such as science and technology studies (STS), the environmental humanities, and the posthumanities, for example, have started to reformulate academic understanding of nature-cultures based on relational thinking. Although the sustainability crisis serves as a contemporary backdrop and in fact calls for such innovative forms of interdisciplinary scholarship, the field of sustainability research has not yet tapped into the rich possibilities offered by relational thinking. Against this background, the purpose of this paper is to identify relational approaches to ontology, epistemology, and ethics which are relevant to sustainability research. More specifically, we analyze how relational approaches have been understood and conceptualized across a broad range of disciplines and contexts relevant to sustainability to identify and harness connections and contributions for future sustainability-related work. Our results highlight common themes and patterns across relational approaches, helping to identify and characterize a relational paradigm within sustainability research. On this basis, we conclude with a call to action for sustainability researchers to co-develop a research agenda for advancing this relational paradigm within sustainability research, practice, and education.  相似文献   

19.
20.
The median total mercury concentration in 898 UK rural topsoils, sampled between 1998 and 2008, was 0.095 μg g−1. Approximate adjustment for unreactive metal produced an estimate of 0.052 μg g−1 for reactive Hg. The highest concentrations were in the north and west, where organic-rich soils with low bulk densities dominate, but the spatial pattern was quite different if soil Hg pools (mg m−2) were considered, the highest values being near to the industrial north of England and London. Possible toxic effects of Hg were best evaluated by comparison with soil Critical Limits expressed as ratios of Hg to soil organic matter, or soil solution Hg2+ concentrations, estimated by chemical speciation modelling. Only a few percent of the rural UK soils showed exceedance, and this also applied to rural soils from the whole of Europe. UK urban and industrial soils had higher Hg concentrations and more cases of exceedance.  相似文献   

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