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811.
Abstract

A unique form of optical ecological traps is polarised light pollution. Typical sources of this phenomenon is asphalt roads that attract a variety of polarotactic aquatic adult insects seeking horizontally polarised sources recognized as water surfaces. Several harmful effects of polarised light pollution have been previously demonstrated but no quantitative data are available in regard to the loss of a given adult population under these conditions. Our objective was to study the impact of an asphalt road parallel to a creek on the stonefly Perla abdominalis (Guérin-Méneville, 1838 Guérin-Méneville, F. E. (1838), ‘Genre Perle’, in Iconographie du Règne animal de G. Cuvier, ed. F. E. Guérin-Méneville, pp. 393395. [Google Scholar]). Throughout a three-year study, by comparing the number of exuviae along a stream and the number of adult individuals attracted by the road, we established that 19.6% of the females were trapped by the nearby road. By measuring the reflection–polarisation characteristics of the stream and asphalt surface, we demonstrated that the road may act as attractive, supernormal stimulus for adult females.  相似文献   
812.
ABSTRACT

Enzymes are powerful tools that help sustain a clean environment in several ways. They are utilized for environmental purposes in a number of industries including agro-food, oil, animal feed, detergent, pulp and paper, textile, leather, petroleum, and specialty chemical and biochemical industry. Enzymes also help to maintain an unpolluted environment through their use in waste management. Recombinant DNA technology, protein engineering, and rational enzyme design are the emerging areas of research pertaining to environmental applications of enzymes. The future will also see the employment of various technologies including gene shuffling, high throughput screening, and nanotechnology. This article presents an overview of the enzymatic applications in pollution control and the promising research avenues in this area.  相似文献   
813.
814.
815.
Four brominated aliphatic hydrocarbons (14), including a novel brominated ene-tetrahydrofuran named as mutafuran H (1), and five sterols (59) were isolated from the South China Sea sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of NMR (1H, 13C NMR, HSQC, HMBC, 1H–1H COSY, and NOESY), MS, and optical rotation analysis. Known compounds were identified by comparison of their NMR data with those reported in the literature. Compounds 14, and 69 were evaluated for their toxicity against Artemia salina larvae, and anti-acetylcholinesterase activity.  相似文献   
816.
Epidemiologic studies of the short-term effects of ambient particulate matter (PM) on the risk of acute cardiovascular or cerebrovascular events often use data from administrative databases in which only the date of hospitalization is known. A common study design for analyzing such data is the case-crossover design, in which exposure at a time when a patient experiences an event is compared to exposure at times when the patient did not experience an event within a case-control paradigm. However, the time of true event onset may precede hospitalization by hours or days, which can yield attenuated effect estimates. In this article, we consider a marginal likelihood estimator, a regression calibration estimator, and a conditional score estimator, as well as parametric bootstrap versions of each, to correct for this bias. All considered approaches require validation data on the distribution of the delay times. We compare the performance of the approaches in realistic scenarios via simulation, and apply the methods to analyze data from a Boston-area study of the association between ambient air pollution and acute stroke onset. Based on both simulation and the case study, we conclude that a two-stage regression calibration estimator with a parametric bootstrap bias correction is an effective method for correcting bias in health effect estimates arising from delayed onset in a case-crossover study.  相似文献   
817.
赣江上游沉积物重金属空间分布及污染特征   总被引:1,自引:0,他引:1  
为了解赣江上游表层沉积物重金属污染特征,采集赣江上游38个样品,采用电感耦合等离子体质谱仪(ICP-MS,Agilent 8800)分析沉积物中重金属含量,结合内梅罗综合污染指数法、地累积指数法、主成分分析及沉积物质量基准等研究赣江上游沉积物中重金属污染程度,分析污染物可能的来源及评价其存在的生态风险。结果表明:赣江上游沉积物中W、Cr、Mn、Cu、Zn、As、Cd、Hg、Pb等9种重金属的平均含量分别为12.30、4.40、999.84、9.72、293.81、47.66、2.85、1.34、63.68 mg·kg-1;除Cr和Cu外,其余7种重金属的平均值均超过江西省土壤背景值。内梅罗综合污染评价表明,赣江上游表层沉积物中47.37%的采样点呈严重污染,28.95%采样点污染明显,其中污染程度章水段>桃江段>贡江段;地积累指数法显示,Mn、As、W、Pb呈轻度污染,Cd和Hg呈中度或偏重度污染;主成分分析显示,As、W、Hg、Pb具有相似的污染源,Cr和Mn具有相似的污染源;沉积物质量基准分析表明,对底栖生物可能产生毒性效应的重金属主要是Cd和Hg,主要分布在章水段和桃江段。  相似文献   
818.
本研究采取辽河油田曙光采油厂、欢喜岭采油厂和锦州采油厂井场周边土壤,并以未污染稻田土壤作为对照,分析了各采样点的土壤理化性质、石油烃浓度组成及土壤微生物群落结构。结果表明: 1) 3个采油厂井场周边土壤均受到严重的石油烃污染,但其石油烃浓度及组成存在一定的差异,曙光和欢喜岭采油厂土壤石油烃平均浓度是锦州采油厂的2倍以上;曙光采油厂土壤中胶质沥青质含量最高,而欢喜岭和锦州采油厂土壤中烷烃含量最高,比例均在40%以上。2)与稻田土壤相比,锦州采油厂土壤微生物操作分类单元(OTU)、Chao1指数和Shannon指数升高,而其在曙光和欢喜岭采油厂土壤中降低;各采油厂土壤样品中存在相同的优势菌门及菌属,但丰度存在较大差异。锦州采油厂土壤中分枝杆菌属、假单胞菌属的丰度高,曙光采油厂土壤中鞘氨醇单胞菌属、类诺卡氏菌属、马赛菌属的丰度高,而欢喜岭采油厂土壤中溶杆菌属、硫杆菌属、假节杆菌属的丰度高。3)相关分析表明,鞘氨醇单胞菌属、类诺卡氏菌属、硫杆菌属、马赛菌属、假节杆菌属与总石油烃、总有机碳和胶质沥青质含量呈显著正相关,分枝杆菌属、溶杆菌属、假单胞菌属与总氮和总磷呈显著正相关。本研究系统分析了不同采油厂土壤中石油烃、土壤理化性质和微生物群落特征,揭示了辽河油田污染土壤中特定的优势菌属和群落结构,为辽河油田石油烃污染土壤修复功能微生物筛选及修复过程菌群构建提供理论依据,也为其他油田高效降解菌筛选提供了方法借鉴。  相似文献   
819.
Abstract

Heavy metal pollution in the atmosphere is a major environmental problem, which has important impacts on ecosystems and human health. In this study, the atmospheric deposition of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in Suqian, China, was investigated by using the moss Haplocladium microphyllum as a bioindicator. The survey was carried out during the summer of 2017 at 40 homogenously distributed sampling sites. Cr, Cu, Ni, Pb, V, and Zn were analyzed by inductively coupled plasma atomic emission spectrometry, and Cd was analyzed by inductively coupled plasma mass spectrometry. Wide variations in heavy metals (Cd, Pb, and Zn) indicated that the concentrations of elements are influenced by local emission sources. Spatial distribution maps of the elements were constructed using geographic information system technology. The pollution load index showed that the study area was moderately polluted to unpolluted. Significant positive correlations (p?<?.01) and weak positive correlations (p?<?.05) were identified among some of the elements, indicating that they originated from common sources. A principal component analysis classified the heavy metals into natural and anthropogenic sources, and identified four primary sources: nature soil dust, industry activities, traffic emission, and agricultural activities.  相似文献   
820.
Abstract

Potentially toxic elements and particulate matter (PM) in the ecosystem are regarded as extremely hazardous because of their persistence, toxicity and bioaccumulative characteristics. Therefore, present study was conducted to estimate the ecological and human health risks of potentially toxic elements (Cu, Mn, Pb, Cd and Ni) and particle pollution (TSP, PM10 and PM2.5) at 2 and 60 m roadside distance from 15 different sites at dust polluted megacity of Pakistan. The AQI assessments suggested that the majority of sites were found unhealthy for sensitive at 2 and 60 m roadside distance, which reveals that that quality of road pavement and streets are far below than the required standards resulting huge quantity of dust particles suspended in air by natural and anthropogenic activities. The maximum geo-accumulation index (I geo) values (1.47 and 0.52) and pollution index (PI) values (4.18 and 2.15) were observed for Ni at 2 and 60 m distance away from the muddy edge of the roads. Similarly, maximum contamination factor (CF) values (24.5 and 94.5) and ecological risk index (ERI) values (4.11 and 3.15) were found for Cd at 2 and 60 m. The I geo and PI indicated that the road dust at a distance of 2 m was relatively more contaminated as compared to 60 m roadside distance. Highest cancer risk (CR) values (2.33 adult and 10.9 for children) were observed for Pb at 2 m, while highest CR values (1.21 for adult and 5.67 for children) at 60 m distance. No probable health risk was observed as the total hazard index (HIexp) of all potentially toxic elements was <1. However, children were appeared to be more susceptible to potentially toxic elements. Based on the results, we believe that the exponential increase in traffic load and industries have aggravated the pollution level and it is expected to be increased in the future.  相似文献   
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