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891.
The seasonal changes in the concentrations of aluminium (Al), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), magnesium (Mg), manganese (Mn), lead (Pb), and zinc (Zn) in the leaves of Taraxacum officianale, Plantago lanceolata and Plantago major are investigated. the most convenient periods for sampling are established when the elemental concentrations have minimal variation and are independent on the development of the plant itself. On this basis, the presumption is made that the most appropriate sampling period for herbaceous species for biomonitoring processes is the end of blossoming of the plant or immediately after that.  相似文献   
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彭秀红  李月林  李波  罗芳 《环境工程》2016,34(7):160-164
地气测量是采用液态捕集剂,高效富集地气中纳米微粒,以高灵敏度的ICP-MS分析元素特征的监测方法。针对传统大气颗粒物监测方法,面临大范围高分辨率空气质量监控仍显乏力,固态滤膜本底浓度较高且不均一的技术难题,在研究大气颗粒物物化特征的基础上,结合地气测量法,提出一种新的大气颗粒物元素浓度采样方法。根据成都地区条件实验,新方法能有效富集大气颗粒物,并能较准确反应环境变化特征。  相似文献   
896.
环境意识水平的提升能从根本上改变大学生旅游者传统的思维方式和价值观,内在自觉地规范旅游环境行为和实践活动。以南京林业大学为研究对象,以配额抽样法探讨大学生旅游者学科专业、性别因素对环境意识的影响,研究发现大学生旅游者表现出较好的环境态度和倾向,对旅游环境和生态知识的渴求和认知程度对其整体环境意识水平有较大影响,然而也存在着知行脱节,环境行为滞后于环境情感、意志的现象。应重视高校环境教育工作,努力提升大学生旅游者的环境意识水平。  相似文献   
897.
Plant polyphenols are involved in important ecosystem processes and may affect nutrient cycling. Previous investigations have demonstrated detrimental effects of suboptimal sample treatment on the quantity of extractable plant polyphenols. We compared leaf polyphenol concentrations of 20 tree species from East China in two sample sets collected under different conditions: (a) according to established protocols and stored more than three years, (b) under conditions optimised for leaf polyphenols. We investigated the variance brought about by suboptimal sample handling as compared to the variance caused by the taxonomic range of species. Family-affiliation explained the largest proportion of variance, whereas sample handling had only minor effects. Reducing the taxonomic range increased the impact of differences in sample handling. Additionally, we showed that the concentrations of leaf polyphenols were phylogenetically more conserved than other leaf traits. Non-metric-multi-dimensional scaling revealed similar ordination patterns for leaf polyphenol concentrations in both sample sets with both ordinations being closely correlated. Finally, we computed separate ordinations including an extended set of leaf traits and found that both analyses led to similar ecological conclusions. Consequently, in studies comprising a wide taxonomic range, the adverse effects of suboptimal sample handling may be overridden by the variation brought about by phylogeny.  相似文献   
898.
A method for determining atmospheric concentrations of eight pesticides applied to corn and soybean crops in Mato Grosso state, Brazil is presented. The method involved a XAD-2 resin cartridge coupled to a low volume air pump at 2 L min?1 over 8 hours. Pesticides were recovered from the resin using sonication with n-hexane:ethyl acetate and determined by GC-MS. Good accuracy (76–128%) and precision (CV < 20%) were obtained for atrazine, chlorpyrifos, alpha- and beta-endosulfan, endosulfan sulfate, flutriafol, malathion, metolachlor and permethrin. Method detection ranged from 9.0 to 17.9 ng m?3. This method was applied to 61 gas phase samples collected between December 2008 and June 2009. Atrazine and endosulfan were detected both in urban and rural areas indicating the importance of atmospheric dispersion of pesticides in tropical areas. The simple and efficient extraction method and sampling system employed was considered suitable for identifying pesticides in areas of intense agricultural production.  相似文献   
899.
Abstract: General consensus among scientists, commercial interests, and the public regarding the status of shark populations is leading to an increasing need for the scientific community to provide information to help guide effective management and conservation actions. Experience from other marine vertebrate taxa suggests that public, political, and media pressures will play an increasingly important part in setting research, management, and conservation priorities. We examined the potential implications of nonscientific influences on shark research. In particular, we considered whether lethal research sampling of sharks is justified. Although lethal sampling comes at a cost to a population, especially for threatened species, the conservation benefits from well‐designed studies provide essential data that cannot be collected currently in any other way. Methods that enable nonlethal collection of life‐history data on sharks are being developed (e.g., use of blood samples to detect maturity), but in the near future they will not provide widespread or significant benefits. Development of these techniques needs to continue, as does the way in which scientists coordinate their use of material collected during lethal sampling. For almost half of the known shark species there are insufficient data to determine their population status; thus, there is an ongoing need for further collection of scientific data to ensure all shark populations have a future. Shark populations will benefit most when decisions about the use of lethal sampling are made on the basis of scientific evidence that is free from individual, political, public, and media pressures.  相似文献   
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