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91.
Under laboratory conditions, female rainbow trout were exposed to graded concentrations of water from the River Lambro, a polluted tributary of the River Po, and to the effluent of a large wastewater treatment plant which flows into the River Lambro. In field exposures, trout were held in cages in the River Po upstream and downstream from the confluence of the River Lambro. After 10-day (laboratory) and 30-day (laboratory and field) exposures, trout were examined for several chemical, biochemical and histological endpoints. The results indicated that exposure to complex mixtures of chemicals, including estrogen receptor agonists, aryl-hydrocarbon receptor agonists, and probably antiandrogens, had occurred. Exposure altered the plasma levels of 17β-estradiol and testosterone, and some treatments also enhanced the activity of hepatic ethoxyresorufin O-deethylase. Gonadal histology showed varying levels of degenerative processes characterised by oocyte atresia, haemorrhages, melano-macrophage centres (MMCs), and oogonia proliferation. Liver histology showed less severe effects.  相似文献   
92.
93.
In many cases, the first step in large‐carnivore management is to obtain objective, reliable, and cost‐effective estimates of population parameters through procedures that are reproducible over time. However, monitoring predators over large areas is difficult, and the data have a high level of uncertainty. We devised a practical multimethod and multistate modeling approach based on Bayesian hierarchical‐site‐occupancy models that combined multiple survey methods to estimate different population states for use in monitoring large predators at a regional scale. We used wolves (Canis lupus) as our model species and generated reliable estimates of the number of sites with wolf reproduction (presence of pups). We used 2 wolf data sets from Spain (Western Galicia in 2013 and Asturias in 2004) to test the approach. Based on howling surveys, the naïve estimation (i.e., estimate based only on observations) of the number of sites with reproduction was 9 and 25 sites in Western Galicia and Asturias, respectively. Our model showed 33.4 (SD 9.6) and 34.4 (3.9) sites with wolf reproduction, respectively. The number of occupied sites with wolf reproduction was 0.67 (SD 0.19) and 0.76 (0.11), respectively. This approach can be used to design more cost‐effective monitoring programs (i.e., to define the sampling effort needed per site). Our approach should inspire well‐coordinated surveys across multiple administrative borders and populations and lead to improved decision making for management of large carnivores on a landscape level. The use of this Bayesian framework provides a simple way to visualize the degree of uncertainty around population‐parameter estimates and thus provides managers and stakeholders an intuitive approach to interpreting monitoring results. Our approach can be widely applied to large spatial scales in wildlife monitoring where detection probabilities differ between population states and where several methods are being used to estimate different population parameters.  相似文献   
94.
Environmental Geochemistry and Health - An integrated approach using chemical and microbial indicators has been tested in two different sites of the Campania Plain (Southern Italy) with different...  相似文献   
95.
The pesticides originally designed to kill target organisms are dangerous for many other wild species. Since they are applied directly to the environment, they can easily reach the water basins and the topsoil. A dataset of 125 aromatic pesticides with well-expressed aquatic toxicity towards trout was subjected to quantitative structure activity relationships (QSAR) analysis aimed to establish the relationship between their molecular structure and biological activity. A literature data for LC50 concentration killing 50% of fish was used. In addition to the standard 2D-QSAR analysis, a comparative molecular field analysis (CoMFA) analysis considering the electrostatic and steric properties of the molecules was also performed. The CoMFA analysis helped the recognition of the steric interactions as playing an important role for aquatic toxicity. In addition, the transport properties and the stability of the compounds studied were also identified as important for their biological activity.  相似文献   
96.
Quantitative structure-activity relationships (QSARs) urgently need to be applied in regulatory programs. Many QSAR models can predict the effect of a wide range of substances to different endpoints, particularly in the case of ecotoxicity, but it is difficult to choose the most appropriate model on the basis of the requirements of the application. During the EC-funded project DEMETRA (www.demetra-tox.net) a huge number of QSAR models have been developed for the prediction of different ecotoxicological endpoints. DEMETRA individual models on rainbow trout LC50 after 96 h, water flea LC50 after 48 h and honey bee LD50 after 48 h have been used as a QSAR database to test the advantages of a new index for evaluating model uncertainty. This index takes into consideration the number of outliers (weighted on the total number of compounds) and their root mean square error. Application on the DEMETRA QSAR database indicated that the index can identify the models with the best performance with regard to outliers, and can be used, together with other classical statistical measures (e.g., the squared correlation coefficient), to support the evaluation of QSAR models.  相似文献   
97.
This paper reports the results obtained from the data collected within the European Commission funded project SAFEFOODNET regarding the state of the art in the control of chemical food contaminants in twelve European New Member States and one Associated Candidate Country (Turkey). Information has been gathered on institutions involved in food chemical contamination control, types of contaminants and matrices analyzed, procedures for data quality assurance, purposes of the analyses and accessibility of data in the participant countries. The resulting picture points out the general availability of adequate capabilities for the analysis of food contaminants in the laboratories in charge of control and the performance of the analysis of a large variety of chemicals (persistent organic pollutants, polycyclic aromatic hydrocarbons, pesticides, mycotoxins, heavy metals, radionuclides) in almost each country with few exceptions (dioxins in Bulgaria, Turkey, Latvia, persistent organic pollutants in Lithuania and Malta, polycyclic aromatic hydrocarbons in Malta). The application of validated analytical methods and the process of laboratory accreditation are partially fulfilled within the investigated countries, but still forthcoming for some countries, as in Romania, Turkey and Malta. Information collected on food controls is only partially available online and the language used is prevalently local and English to a lesser extent.  相似文献   
98.
Net primary productivity (NPP) is one of the major ecosystem products on which human societies rely heavily. However, rapid urban sprawl and its associated dense population and economic conditions have generated great pressure on natural resources, food security, and environments. It is valuable to understand how urban expansion and associated demographic and economic conditions affect ecosystem functions. This research conducted a case study in Southeastern China to examine the impacts of urban expansion and demographic and economic conditions on NPP. The data sources used in research include human settlement developed through a combination of MODIS, DMSP-OLS and Landsat ETM+ images, the annual NPP from MODIS, and the population and gross domestic product (GDP) from the 2000 census data. Multiple regression analysis and nonlinear regression analysis were used to examine the relationships of NPP with settlement, population and GDP. This research indicates that settlement, population and GDP have strongly negative correlation with NPP in Southeastern China, but the outcomes were nonlinear when population or GDP reached certain thresholds.  相似文献   
99.
Simulation of a process by means of physical models at a reduced scale is an essential tool in many application, allowing to perform a large number of experimental runs, so as to obtain a quantitative representation of the involved phenomena, at relatively low cost. Some difficulties can arise when the mathematical model derived from the simulation is applied to a real scale problem, in that the scaling of some empirical coefficients with the system size is not obvious at all. As fluid barrier scaling is a difficult task, still not deeply investigated in the scientific literature, the focus of this study is to translate knowledge from research on this topic into practice for industrial application. Following an extensive and accurate experimental work in wind tunnel, the main parameters determining the effectiveness of containment, absorption and dilution of chlorine releases were determined and a mathematical model is developed. In order to frame proper scale-up strategies, the most important result of this study rests on the explicit formulae giving, as a function of the aforesaid parameters, the single pass efficiency, the global absorption efficiency, and the toxic gas concentration downwind the barrier. In the far field, the gas concentration is practically determined only by the rate of atmospheric dispersion of the mass flow-rate of gas escaping the abatement. The absorption efficiencies are related to the drop size and to the mass transfer coefficients in the gas and liquid phases. The mean drop diameter plays an essential role in the absorption efficiency, since it simultaneously acts on air entrainment, interfacial surface and mass transfer coefficient in the gas phase. The evaluation of the mitigation effect for an industrial installation requires the scaling of the entrainment coefficient experimentally determined from wind tunnel testing. All the scaling criteria needed for adapting the proposed model to the design of a spray curtain suitable for the protection from a chlorine release, are amply discussed presenting some carefully designed simulations. Owing to its rather general structure, the model can be applied to different gaseous releases and/or absorbing solutions, provided that proper values of the parameters related with the chemical and physical absorption of the involved substances be theoretically or experimentally obtained in advance.  相似文献   
100.
Environmental Geochemistry and Health - The Riardo basin hosts groundwater exploited for the production of high quality, naturally sparkling, bottled water (e.g., Ferrarelle water), and circulating...  相似文献   
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