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61.
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   
62.
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   
63.
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   
64.
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   
65.
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   
66.
The increasing demand for horticultural products for nutritional and economic purposes by lesser developed countries (LDC's) is well-documented. Technological demands of the LDC's producing horticultural products is also increasing. Pesticide use is an integral component of most agricultural production, yet chemicals are often supplied without supplemental information vital for their safe and efficient implementation. Illiteracy rates in developing countries are high, making pesticide education even more challenging. For women, who perform a significant share of agricultural tasks, illiteracy rates are even higher than for men. The dilemma exists of how a developing country can improve its nutritional and economic situation without giving consideration to social and environmental consequences.  相似文献   
67.
Valiela I  Bowen JL 《Ambio》2003,32(7):476-480
As global warming intensified toward the end of the 20th century, there was a northward shift in winter ranges of bird species in Cape Cod, Massachusetts, USA. These poleward shifts were correlated to local increases in minimum winter temperatures and global temperature anomalies. This evidence, plus other recent results, suggests that during the last two decades global warming has led to massive and widespread biogeographic shifts with potentially major ecological and human consequences. Local habitat changes associated with urban sprawl affected mainly forest birds with more northern winter distributions. In Cape Cod, the effects of warming on bird distributions are more substantial at the start of the 21st century, than those of habitat alteration, but as urban sprawl continues its importance may rival that of global warming.  相似文献   
68.
紫外诱变筛选高效氧化亚铁硫杆菌   总被引:1,自引:0,他引:1  
为了取得高效氧化亚铁硫杆菌(T.f菌),采用紫外线诱变处理,对照射1.5 min,3 min,5 min的菌株进行实验测试,结果表明,T.f3将Fe^2+完全氧化由7 d缩短为5 d,并且在较低SO3^2-浓度范围内,Fe2+浓度与SO3^2-的氧化速率呈正相关性,但当菌液浓度一定时,增加Fe2+浓度,SO3^2-的氧化速率不会明显增加。  相似文献   
69.
双酚A(BPA)作为典型的环境内分泌干扰物,由于其在环境中痕量浓度即可对生物产生内分泌干扰效应,因此受到了越来越广泛的关注。城市污水为BPA重要污染源,污水处理过程中部分BPA转移到污泥中,成为潜在的环境隐患。本文综述了双酚A在环境中的赋存情况以及相应的萃取技术、分析检测方法。此外,通过对比不同的回收率与检测下限,对几种常用的分析方法进行了比较,并展望了这一领域未来的研究发展趋势。  相似文献   
70.
我国矿山地质环境评价方法研究现状及展望   总被引:2,自引:0,他引:2  
中国矿山地质环境研究起步比较晚,但发展迅猛。本文阐述了中国矿山地质环境评价方法现状,介绍和评论了中国矿山地质环境评价的常用工作方法,分析了中国矿山地质环境评价存在的主要问题,并就未来中国矿山地质环境评价方向提出了一些建议。  相似文献   
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