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51.
Pesticides are among the most widely used chemicals in the world. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticide residues through their diets. Scientists do not yet have a total understanding of the health effects of these pesticide residues. This work aims to determine differences in terms of pesticide residue content in Portuguese strawberries grown using different agriculture practices. The Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation method was conducted and shown to have good performance for multiclass pesticides extraction in strawberries. The screening of 25 pesticides residue was performed by gas chromatography?Ctandem mass spectrometry. In quantitative validation, acceptable performances were achieved with recoveries of 70?C120 and <12?% residual standard deviation for 25 pesticides. Good linearity was obtained for all the target compounds, with highly satisfactory repeatability. The limits of detection were in the range of 0.1?C28???g/kg. The method was applied to analyze strawberry samples from organic and integrated pest management (IPM) practices harvested in 2009?C2010. The results showed the presence of fludioxonil, bifenthrin, mepanipyrim, tolylfluanid, cyprodinil, tetraconazole, and malathion when using IPM below the maximum residue levels.  相似文献   
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Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children’s exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1?±?4.3 % to 264.7?±?3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3?±?1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5?±?2.0 % to 118.8?±?1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose–response relationship or a mixture toxicity effect.  相似文献   
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Conflicts between human demands for clean water and terrestrial ecosystems’ needs for water are increasing. Such conflicts are stronger in the case of groundwater, as one of the cleanest forms of drinking water, and are expected to increase in frequency, in the context of population growth and climatic changes. This paper argues that behavioral approaches are essential not only toward understanding how socio-ecological conflicts emerge, but also how they could be overcome. A theoretical the framework is proposed, which suggests that the behaviors/actions of actors who sustain such conflicts can be understood by examining their ‘boundary judgments’ regarding natural resources and sustainability, in interaction with their powers/resources to implement the preferred behaviors. The concept of boundary judgements is rarely used in investigating sustainability conflicts. This concept is operationalized in relation to nature-society conflicts and applied empirically to illuminate the conflict in a case study from the Netherlands. Further, the theoretical framework suggests a parsimonious, yet comprehensive, typology of mechanisms that can be used to change/‘converge’ the behaviors and actions of the actors contributing to the problem, toward conflict closure. These are referred to as convergence mechanisms and can be persuasive, enabling or constraining. The paper concludes with reflections on the practical usefulness of the framework and concretes suggestions for further research, drawing on these convergence mechanisms and their interactions with boundary judgments on natural resources and sustainability.  相似文献   
54.
For a long time, watershed models focused on the transport of chemicals from the terrestrial part of the watershed to the surface water bodies by leaching and erosion. After the substances had reached the surface water, they were routed through the channel network often without any further transformation. Today, there is a need to extend watershed models with in-stream processes to bring them closer to natural conditions and to enhance their usability as support tools for water management and water quality policies. This paper presents experience with implementing in-stream processes in a ecohydrological dynamic watershed model and its application on the large scale in the Saale River basin in Germany. Results demonstrate that new implemented water quality parameters like chlorophyll a concentrations or oxygen amount in the reach can be reproduced quite well, although the model results, compared with results achieved without taking into account algal and transformation processes in the river, show obvious improvement only for some of the examined nutrients. Finally, some climate and water management scenarios expected to impact in-stream processes in the Saale basin were run. Their results illustrate the relative importance of physical boundary conditions on the amount and concentration of the phytoplankton, which leads to the conclusion that measures to improve water quality should not only take nutrient inputs into account but also climate influences and river morphology.  相似文献   
55.
The biogeochemical and ecological assessment of the industrial city territory including urban soils and trees was carried out. Chemical (macroelement and microelement) composition of the city soils, morphological and biochemical properties of the linden leaves, possible impact of de-icing salts on soil and tree state, the correlation between the content of trace elements, and the S-containing plant compounds (phytochelatins) were included in the assessment. It was found that concentrations of trace elements in the soils near road with intensive traffic are changed from the soils, located at a distance of 40–50 m from the road. They have higher concentrations of As, Fe, Mn, Se, and Sr and lower concentration of Zn. The linden leaves from the roadside were characterized by the increase in As, Cu, Fe, Zn, and Cr and sharp decrease in the Mn and Sr concentrations. The analysis of soil water extracts showed a slight decrease of pH and low content of Ca, Mg, K, and Na for the distant sites. The phytochelatin test of linden leaves was weakly effective as well as asymmetry degree study of leaf lamina. The main differences were observed in the damage symptoms of leaves (chlorosis and necrosis) and the content of pigments (chlorophyll and carotenoids). The biochemical and ecological assessment of soils and trees showed relatively satisfactory ecological state of the investigated area in Moscow. The data obtained shows the weak local impact of the application of de-icing salts and automobile emissions.  相似文献   
56.
高羊茅对微牛物强化修复石油污染土壤影响的研究   总被引:1,自引:0,他引:1  
进行了石油污染土壤在外源微生物菌剂和高羊茅协调作用下的强化修复试验,对外源微生物菌剂在不同植被条件下的去除特征进行了分析。分别进行了没有植物、高羊茅草坪、高羊茅草种新育草坪3种不同情况下的降解试验。结果表明,微生物菌剂对石油污染土壤有着良好的降解效果,去除率为36%-43%,而没有微生物菌剂和植被作用下的对照组的去除率仅为5.74%~6.0%;高羊茅草坪能够提高微生物进一步降解的能力,在直接铺草坪的情况下,去除率可以达到51%~62%;在播种高羊茅草种,形成新嫩草坪的情况下,去除率为48%~54%。结果表明,在直接铺高羊茅草坪条件下,微生物菌剂的强化分解作用可以提高41.6%-44.2%,在新嫩草坪作用下能够提高27.9%-30.6%,可以认为高羊茅草坪对于提高微生物菌剂的强化分解有一定的促进作用。在试验过程中还对不同修复的土壤pH值变化特性进行了分析。  相似文献   
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The giving-up density (GUD) framework provides a powerful experimental approach with a strong theoretical underpinning to quantify foraging outcomes in heterogeneous landscapes. Since its inception, the GUD approach has been applied successfully to a vast range of foraging species and foraging scenarios. However, its application is not simple, as anyone who has tried to use it for the first time might attest. Limitations of the technique were noted at its conception, yet only the artificiality of the patches, the appropriateness of the food resource, and the possibility of multiple visiting foragers were identified. Here we show the current uses of GUD and outline the practical benefits as well as the often overlooked limitations of the technique. We define seven major points that need to be addressed when applying this methodology: (1) the curvilinearity between harvest rate and energy, (2) the energetic state of the forager, (3) the effect of group foraging, (4) food quality and substrate properties, (5) the predictability of the patch, (6) behavioral traits of the forager, and (7) nontarget species. We also suggest how GUD experiments can be enhanced by incorporating complementary methods (such as cameras) to better understand the foraging processes involved in the GUD itself. We conclude that the benefits of using GUD outweigh the costs, but that its limitations should not be ignored. Incorporating new methods when using GUD can potentially offer novel and important insights into the study of foraging behavior.  相似文献   
60.
The Common Agricultural Policy (CAP) of the European Union (EU) has dramatically changed after 1992, and from then on the CAP focused on the management of direct income subsidies instead of production-based subsidies. For this focus, Member States (MS) are expected to establish Integrated Administration and Control System (IACS), including a Land Parcel Identification System (LPIS) as the spatial part of IACS. Different MS have chosen different solutions for their LPIS. Currently, some MS based their IACS/LPIS on data from their Land Administration Systems (LAS), and many others use purpose built special systems for their IACS/LPIS. The issue with these different IACS/LPIS is that they do not have standardized structures; rather, each represents a unique design in each MS, both in the case of LAS based or special systems. In this study, we aim at designing a core data model for those IACS/LPIS based on LAS. For this purpose, we make use of the ongoing standardization initiatives for LAS (Land Administration Domain Model: LADM) and IACS/LPIS (LPIS Core Model: LCM). The data model we propose in this study implies the collaboration between LADM and LCM and includes some extensions. Some basic issues with the collaboration model are discussed within this study: registration of farmers, land use rights and farming limitations, geometry/topology, temporal data management etc. For further explanation of the model structure, sample instance level diagrams illustrating some typical situations are also included.  相似文献   
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