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41.
利用制备气相色谱仪分离塔里木天然气中N2 并测定同位素比值 ,结果显示不同区域天然气氮的含量及其同位素比值不同 ,塔中、塔北与和田河地区天然气含氮量高 ,δ15N低 ,库车天然气则相反。结果还显示塔里木原油与天然气氮同位素比值具有可比性 ,表明同源油 气成因上的内在联系  相似文献   
42.
Environmental Science and Pollution Research - Previous studies have reported that daily average temperature is connected with respiratory diseases (RD), but proof is limited for the influence of...  相似文献   
43.
Our best understanding of marine mammal mating systems comes from land-mating pinnipeds. Logistical problems of observing behavior at sea have limited our ability to make inferences about species with aquatic-mating systems, which comprise over half the pinnipeds. The mating systems of these species likely involve different mating tactics than land-mating species. We used several methods in combination (e.g., animal-borne cameras, radio telemetry, time-depth recorders, and DNA paternity assessment) to provide a comprehensive study of the aquatic-mating tactics of harbor seal males. Males decreased time offshore (26.0 vs 14.8%) and increased time near shore (33.8 vs 43.7%) between premating and mating periods, respectively. Concomitantly, males reduced foraging effort and increased activities associated with competition for females (e.g., visual/vocal displays and threats). As females come into estrus near the end of lactation and spend more time at sea, males reduced their near-shore ranges (4.2 vs 1.0 km2), which were clustered within 1–1.5 km of the beach where females attended their pups. Body mass of males was not a major factor affecting their reproductive behavior. From a small number of paternity assignments to study males, it appears that females select males. These combined results are more consistent with a lek-type mating system than with the territorial or female defense systems characteristic of land-mating pinnipeds.  相似文献   
44.
Effectively addressing the health risks of climate change necessitates an active crosssectoral approach because health risks arise predominantly via sectors such as water, agriculture and energy. Much has been written on climate change and its impact on health, but little attention has focused on the realpolitik of how to progress the development and implementation of health-relevant strategies and policies to reduce this impact. The objective of this paper is to propose three solutions to address current deficiencies: i) strengthening the capacity and understanding of health officials in relation to climate change and health; ii) improving cross-sectoral partnerships with sectors relevant to climate change and health, and iii) identifying organisations influential in the development of climate change mitigation and adaptation strategies and policies, with a view to better target advocacy efforts. Practical examples of each solution are provided. In conclusion, as a steward of public health, the health sector must take the initiative to encourage a cross-sectoral approach that includes capacity development, coupled with an understanding of influential organisations. If this is done effectively, health, social and economic development goals can be reached more efficiently.  相似文献   
45.
介绍了抗生素制药废水的来源及成因。根据抗生素制药废水高浓度、难降解、可生化性差等特点,综述了近年国内外抗生素制药废水处理中应用各种物理、化学、生物处理技术处理的试验情况及进展。其中物理处理技术有:混凝、沉淀、气浮、吸附和膜过滤等,化学处理技术有:氯氧化、高铁酸盐氧化、铁碳微电解、高级氧化工艺等,生物处理技术有好氧处理法、厌氧处理法等。指出需根据当前形势从技术经济角度选用合适的组合工艺处理不同种类的抗生素制药废水,并提出展望。  相似文献   
46.
渤海湾大气金属元素沉降和来源解析研究   总被引:3,自引:0,他引:3  
干湿沉降是污染物从大气进入到地表生态环境的主要途径.渤海湾临近大气污染严重的京津冀地区,同时受航运交通排放影响,但渤海湾大气金属元素沉降量及其来源并不十分清楚.本研究于2016年11月—2017年10月在渤海西岸采集了大气沉降样品,利用电感耦合等离子体质谱仪(ICP-MS)对样品中25种金属元素的含量进行了测定分析,估算了大气金属沉降量并进行了源解析.结果表明:沉降样品中25种元素的浓度变化范围为2458.8μg·L~(-1)(Ca)~9.9 ng·L~(-1)(Th),年沉降量变化为1229.9 mg·m~(-2)·a~(-1)(Ca)~5.0μg·m~(-2)·a~(-1)(Th).受降水量季节分布的影响,多数金属元素的沉降量在夏季最高,春秋季较低.除Be、Fe、Ni、Cr、Al、Th和U等元素外,其余18种元素都有不同程度的富集,特别是Cd、Ag、Se和Sb等元素已高度富集.燃煤(12.8%)、扬尘(25.9%)、工业(33.1%)和航运(28.2%)是渤海湾沉降样品中金属元素的主要来源,尤其是航运排放对海湾大气Sb、Cd和Mo沉降具有显著贡献.研究结果可为京津冀区域海陆协同发展和环境质量改善提供科学参考.  相似文献   
47.
The low activity of Anammox bacteria at low temperatures and competition from nitrite oxidation bacteria(NOB) when treating low strength wastewater have been major bottlenecks in implementing Anammox in mainstream wastewater treatment. By intermittent high strength feeding(IHSF) and stepwise temperature reduction, stable operation of a granular Anammox reactor was realized at low temperatures(down to 15°C) for 28 days when treating low strength synthetic wastewater. The nitrogen loading rate reached 1.23–1.34 kgN/m~3/day,and the total nitrogen removal rate reached 0.71–0.98 kgN/m~3/day. The IHSF enriched the Anammox sludge in high strength cycles and compensated for sludge loss in low strength cycles, and the high concentration of ammonium in high strength cycles inhibited NOB. The 16 SrRNA gene sequencing results revealed that Candidatus Kuenenia was predominant in the reactor at low temperatures.  相似文献   
48.
采用盆栽土壤模拟试验方法,以油菜(Brassica campestris)为供试植物,通过向土壤中接种微生物,研究了四种菌株JA1,JA2,JA3,JA4对油菜吸收Cd的效果影响。结果表明:菌株JA1,JA2,JA4不仅可以促进植株的生长,分别使油菜的生物量提高17%,28%和32%,而且增强了植株对土壤Cd的吸收,使油菜地上部富集量较对照提高了26.8%,48.8%和65.9%,植物提取量较对照增加了48.9%,76.1%和119%,并且可有效促进土壤Cd的活化,分别使土壤Cd的有效态含量提高了25.9%,59.2%和41.9%;菌株JA3则使其植株地上部富集量、植物提取量和土壤Cd有效态含量降低,较对照降低了14.6%,11.8%和13.6%。各处理的叶绿素和可溶性蛋白含量均略高于对照。  相似文献   
49.
为调查滏阳河水系的重金属污染状况,研究河流重金属污染对水生生物的毒性,根据河流结构、水文条件、排污口分布并考虑空间分布的均匀性,选取66个采样位点,采集河水及对应的表层沉积物样品,分析了样品中的重金属含量。用斜生栅藻和青海弧菌Q67作为模式生物,根据滏阳河水重金属污染较严重的邯郸近郊2号采样点采集水样的重金属含量配制系列重金属浓度的模拟河水进行重金属污染河水的生态毒性测试。结果表明,在全部66个采样点中,29个采样点河水重金属含量超过国家地表水III类水体重金属含量标准,主要污染元素是Hg、Pb、Cr、Zn。几乎所有采样点河水Mn和Fe含量都大大高于国家集中式生活饮用水地表水源地补充项目规定的标准限值。根据2号采样点河水样品中的重金属含量配成的模拟河水对青海弧菌Q67的EC_(50)值为6.65%,为毒性极强的污染物。模拟河水样品对斜生栅藻的抑制作用较小,在实验的最高浓度下(1 000倍河水重金属含量)暴露4 d尚未引起半数藻细胞死亡。随河水重金属浓度上升,斜生栅藻超氧化物歧化酶(SOD)活性总体上呈现先升高后降低的趋势,丙二醛(MDA)含量变化则与此相反,反映河水重金属污染可引起藻细胞的氧化损伤。叶绿素a和b含量则随暴露浓度的提高逐渐降低。在重金属浓度达到2号采样点河水的10%时,斜生栅藻叶绿素a含量已有显著降低,MDA含量显著升高,海河流域重金属污染对生态系统的影响应予以重视。河水发光菌Q67的生长抑制率、斜生栅藻的叶绿素a和MDA含量可以作为评估河流重金属污染生态危害的指标。  相似文献   
50.
The Waquoit Bay Watershed ecological risk assessment was performed by an interdisciplinary and interagency workgroup. This paper focuses on the steps taken to formulate the analysis plan for this watershed assessment. The workgroup initially conducted a series of meetings with the general public and local and state managers to determine environmental management objectives for the watershed. The workgroup then decided that more information was needed on the impacts of six stressors: nutrient enrichment, physical alteration of habitat, altered freshwater flow, toxic chemicals, pathogens, and fisheries harvesting. Assessment endpoints were selected to establish the link between environmental management objectives, impacts of stressors, and scientifically measurable endpoints. The following assessment endpoints were selected: estuarine eelgrass cover, scallop abundance, finfish diversity and abundance, wetland bird distribution and abundance, piping plover distribution and abundance, tissue contaminant levels, and brook trout distribution and abundance in streams. A conceptual model was developed to show the pathways between human activities, stressors, and ecological effects. The workgroup analyzed comparative risks, by first ranking stressors in terms of their potential risk to biotic resources in the watershed. Then stressors were evaluated by considering the components of stressors (e.g., the stressor chemical pollution included both heavy metals and chlorinated solvents components) in terms of intensity and extensiveness. The workgroup identified nutrient enrichment as the major stressor. Nutrient enrichment comprised both phosphorus enrichment in freshwater ponds and nitrogen enrichment within estuaries. Because phosphorus impacts were being analyzed and mitigated by the Air Force Center for Environmental Excellence, this assessment focused on nitrogen. The process followed to identify the predominant stressor and focus the analyses on nitrogen impacts on eelgrass and scallops will serve as an example of how to increase the use of the findings of a watershed assessment in decision making.  相似文献   
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