Assessing environmentally significant effects: a better strength-of-evidence than a single P value?

Interpreting a P value from a traditional nil hypothesis test as a strength-of-evidence for the existence of an environmentally important difference between two populations of continuous variables (e.g. a chemical concentration) has become commonplace. Yet, there is substantial literature, in many disciplines, that faults this practice. In particular, the hypothesis tested is virtually guaranteed to be false, with the result that P depends far too heavily on the number of samples collected (the ‘sample size’). The end result is a swinging burden-of-proof (permissive at low sample size but precautionary at large sample size). We propose that these tests be reinterpreted as direction detectors (as has been proposed by others, starting from 1960) and that the test’s procedure be performed simultaneously with two types of equivalence tests (one testing that the difference that does exist is contained within an interval of indifference, the other testing that it is beyond that interval—also known as bioequivalence testing). This gives rise to a strength-of-evidence procedure that lends itself to a simple confidence interval interpretation. It is accompanied by a strength-of-evidence matrix that has many desirable features: not only a strong/moderate/dubious/weak categorisation of the results, but also recommendations about the desirability of collecting further data to strengthen findings.     

对叶绿素a测定方法的改进

近年来的每年夏季 ,太湖某些水域都不同程度的出现大量藻类 ,个别监测点位的藻类密度高达7 6亿个 /Ｌ。由于藻类计数方法繁琐 ,藻类暴发期对藻类密度的监测工作显得力不从心。藻类属于低等浮游植物 ,各门藻类均含有叶绿素ａ ,测定叶绿素ａ可作为藻类现存量的一个重要指标。因此 ,通常可用叶绿素ａ来表示藻类含量的高低[1 ,2 ] 。叶绿素ａ测定方法较藻类计数更为简便、快捷。通过实践 ,对叶绿素ａ测定方法作一些改进。《环境监测技术规范》(以下简称《规范》)第 4册生物监测 (水环境 )部分关于叶绿素ａ的测定是将滤过水样的滤膜 ,置于低温冰…     

Systematic monitoring of heathy woodlands in a Mediterranean climate—a practical assessment of methods

Practical and useful vegetation monitoring methods are needed, and data compatibility and validation of remotely sensed data are desirable. Methods have not been adequately tested for heathy woodlands. We tested the feasibility of detecting species composition shifts in remnant woodland in South Australia, comparing historical (1986) plot data with temporal replicates (2010). We compared the uniformity of species composition among spatially scattered versus spatially clustered plots. At two sites, we compared visual and point-intercept estimation of cover and species diversity. Species composition (presence/absence) shifted between 1986 and 2010. Species that significantly shifted in frequency had low cover. Observations of decreasing species were consistent with predictions from temperature response curves (generalised additive models) for climate change over the period. However, long-term trends could not be distinguished from medium-term dynamics or short-term changes in visibility from this dataset. Difficulties were highlighted in assessing compositional change using historical baselines established for a different purpose in terms of spatial sampling and accuracy of replicate plots, differences in standard plot methods and verification of species identifications. Spatially clustered replicate plots were more similar in species composition than spatially scattered plots, improving change detection potential but decreasing area of inference. Visual surveys detected more species than point-intercepts. Visual cover estimates differed little from point-intercepts although underestimating cover in some instances relative to intercepts. Point-intercepts provide more precise cover estimates of dominant species but took longer and were difficult in steep, heathy terrain. A decision tree based on costs and benefits is presented assessing monitoring options based on data presented. The appropriate method is a function of available resources, the need for precise cover estimates versus adequate species detection, replication and practical considerations such as access and terrain.     

Multisource emission retrieval within a biogas plant based on inverse dispersion calculations—a real-life example

Open digestate storage tanks were identified as one of the main methane (CH₄) emitters of a biogas plant. The main purpose of this paper is to determine these emission rates using an inverse dispersion technique in conjunction with open-path tunable diode laser spectroscopy (OP-TDLS) concentration measurements for multisource reconstruction. Since the condition number, a measure of “ill-conditioned” matrices, strongly influences the accuracy of source reconstruction, it is used as a diagnostic of error sensitivity. The investigations demonstrate that the condition number for a given source-sensor configuration in the highly disturbed flow field within the plant significantly depends on the meteorological conditions (e.g., wind speed, stratification, wind direction, etc.). The CH₄ emissions are retrieved by removing unrepresentative periods with high condition numbers, which indicate uncertainty in recovering the individual sources. In a final step, the CH₄ emissions are compared with the maximum biological methane potential (BMP) in the digestate analyzed under laboratory conditions. The retrieved methane emission rates represent an average of 50 % of the maximum BMP of the stored digestate in the winter months, while they comprised an average of 85 % during the measurement campaigns in the summer months. The results indicate that the open tanks have the potential to represent a substantial emission source even during colder periods.     

淡水中叶绿素a测定方法的探讨

对分光光度法测定叶绿素a中样品研磨转移损失,离心后750nm处吸光值达不到0.005要求,加酸消除脱镁叶绿素,加酸量及加酸后测定时间等方面进行对比实验研究,提出了对分光光度法测定叶绿素a修改建议.     

水体中叶绿素a测定方法的研究

对水体中叶绿素a的测定方法进行了研究,确定了乙醇免研法测定水体中叶绿素a的实验条件。用95%乙醇替代90%丙酮作为萃取剂,用高温免研磨萃取替代研磨萃取,其结果是乙醇免研法与丙酮法测定结果的相对偏差在可接受范围内; 同时对测定结果进行统计分析显示, 乙醇法的测定结果与丙酮法无显著性差异,且乙醇免研法萃取效率有所提高,其测定结果均略高于丙酮法,说明乙醇免研法可以替代丙酮法。     

分光光度法测定叶绿素a的比较

比较了《水和废水监测分析方法》(第四版)和ISO 10260:1992(E)中测定叶绿素a的典型方法,结果表明两种方法的测定结果之间既存在显著性差异,又有一定的相关性,从提取方法、提取溶剂和计算公式等方面讨论了原因,指出ISO方法提取效率更高,操作更简便。     

地表水浮游植物叶绿素a测定方法比较研究

比较了浮游植物叶绿素a测定方法中的丙酮萃取法和热乙醇萃取法.结果表明,应用反复冻融植物细胞的丙酮萃取法对地表水中浮游植物叶绿素a的萃取率显著高于其他方法,且重复测定的精密度较高.     

Test of a Modelling System for Estimating Nitrogen Leaching – A Pilot Study in a Small Agricultural Catchment

Nitrogen leaching is a world-wide concern for the quality of ground- and surfacewater. Measures to abate this is still limited by a lack of understanding mechanisms behind all factors describing the leaching process, time lags between countermeasures and improvement in waterquality and spatial distribution of nitrogen leaching. The purpose of this study was to do an initial test of the SOILNDB model system which is built on the existing mechanistic SOIL and SOILN models and an automatic parameterization procedure for use of simplified input data. The test was done by simulating nitrogen leaching from each of the 150 fields in a small catchment during a three-year study period. The simulated mean root-zone nitrogen leaching rate from all the fields in the catchment was compared to measurements of nitrogen flow in the stream draining the catchment and showed good agreement in between-year dynamics.     

Residents’ concerns and attitudes toward a municipal solid waste landfill: integrating a questionnaire survey and GIS techniques

The ever-growing industry of municipal solid waste (MSW) disposal appeals to the growing need for disposal facilities, and MSW treatment facilities are increasingly an environmental and public health concern. Residents living near MSW management facilities are confronted with various risk perceptions, especially odour. In this study, in an effort to assist responsible decision-makers in better planning and managing such a project, a structured questionnaire was designed and distributed to assess the nearby residents’ concerns and attitudes surrounding the Laogang Landfill in Shanghai. Geographic information system techniques and relevance analysis were employed to conduct the spatial analysis of physical perceptions, especially odour annoyance. The findings of the research indicate that a significant percentage of the responding sample was aware of the negative impacts of landfills on the environment and public health, and residents in close proximity preferred to live farther from the landfill. The results from the spatial analysis demonstrated a definite degree of correlation between odour annoyance and distance to the facility and proved that the benefits of the socially disadvantaged have been neglected. The research findings also direct attention to the important role of public participation, information disclosure, transparency in management, and mutual communication to avoid conflicts and build social trust.     

导数同步荧光法测定绿藻叶绿素a浓度

建立了绿藻中叶绿素a的导数同步荧光检测法。该方法快速、简便,不需要复杂的前处理。叶绿素a的线性范围为0.02～125μg/L,检出限为0.25μg/L,回收率为97.0%～103.8%。     

苯并[a]芘分析方法进展

一、液相色谱法和高效液相色谱法 HPLC技术近年发展较快,提供了测定PAHs的有力工具。以紫外和荧光作为HPLC的检测器,很适合于PAHs的测定。Y.Kamada等分析大气飘尘颗粒物时,以超声波萃     

岳阳南湖叶绿素a及其水质关系分析

通过对南湖水环境中叶绿素a的测定并同时分析其水质,结果表明,南湖水域叶绿素a呈现明显的时空变化特征:夏季>春季>秋季>冬季,麦子港>湖心。叶绿素a含量与环境因子有关,如水温、水质营养因子、BOD5、CODMn有关,南湖N、P满足藻类生长需要,春季总P对数值与夏季叶绿素a对数值成线性关系。南湖叶绿素a含量变化范围在1.75～3.62mgm3,说明南湖水体处于中富营养状态。     

近58 a巴音郭楞蒙古自治州沙尘天气气候特征分析

利用巴音郭楞蒙古自治州(以下简称巴州)境内各气象站1961—2019年统计的逐日天气气象资料,分析巴州沙尘天气的地理分布、时空分布及年际变化。结果表明：沙尘天气的分布受地形地貌影响较大,在巴州南、北部较高海拔山区基本无沙尘天气,巴州南部平原地区若羌县、且末县沙尘天气最多;巴州平原地区全年都有沙尘天气出现,其中,春季(3—5月)沙尘天气最多,冬季沙尘最少;自1961年以来库尔勒市沙尘、浮尘、扬沙、沙尘暴天气表现为减少的趋势。但2010年以来,浮尘天气日数有明显反弹,产生这种反弹现象的主要原因是近几年气候变暖,气温冷暖变幅加大,极端灾害性天气事件频发等。     

民勤县近50a来日照时数变化特征分析

利用民勤县气象站1960~2009年的逐月、逐季、逐年的日照时数观测资料,采用气候倾向率分析法对民勤县近50a日照时数的变化特征进行分析,得出民勤县近50a来日照时数的变化特征。结果表明:近50a来民勤县年日照时数总体呈增加趋势,在四季中,春、夏、秋、冬季日照时数均呈增加趋势并以春季和夏季增加幅度最为显著,变化趋势最为明显,对年日照时数的贡献率最大,秋、冬季增加幅度略小。近50a中民勤县年日照时数最多为2006年的3423.5h,最少为1975年的2763h,两者相差达660.5h,说明年日照时数的变化较大。     

乙醇法测定浮游植物叶绿素a含量的讨论

采用热乙醇法以及乙醇冷冻提取法测定浮游植物叶绿素a含量,以比较两种方法的效果.实验结果表明,两种方法的测定值之间有较好的线性相关关系.热乙醇法快速高效,可以替代国内使用较多的乙醇冷冻提取法.     

微囊藻中叶绿素a提取方法的优化

用组织研磨、浸泡提取、热浴超声3种提取方法和丙酮、甲醇、乙醇3种提取溶剂,从实验室纯培养微囊藻中提取叶绿素a,并以高效液相色谱法测定其质量浓度。结果表明,经组织研磨破碎藻细胞后用甲醇提取的效果好于丙酮和乙醇,经浸泡和超声破碎藻细胞后用乙醇的提取效果好于丙酮和甲醇;使用乙醇-热浴超声法在所有的试验组合中获得最佳提取效果,条件为：乙醇温度为50℃-55℃,超声6min-8min后再静置提取5h-6h。