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61.
对白洋淀几种不同食性鱼体内六六六和DDT残留量分析表明,草食性鱼体内农药残留量最少,六六六含量为59.3μg/kg,DDT含量为29.6μg/kg;其次是杂食性鱼类,六六六含量为90.4μg/kg,DDT含量为108.5μg/kg;肉食性鱼体内农药残留量最高,六六六含量为110.7μg/kg,DDT含量为124.4μg/kg。鱼体对DDT的浓缩因子为311~1244,明显高于六六六的177~368。鱼体内BHC4种异构体的残留顺序为δ>α>γ>β,与其在水体中的比例α>γ>δ>β略有不同。鱼体内DDT主要以代谢物p,p'-DDE的形式存在,但个别样品中少量的p,p'-DDD及o,p'-DDT的检出,表明白洋淀水生生态系统最近受到DDT的轻度污染。本项研果与1975~1977年检测结果进行比较;白洋淀鱼体内六六六残留量显著下降,下降率为15.8%~79.2%;DDT残留量却明显增加(草食性鱼类除外),增加率约为47.8%~97.8%。  相似文献   
62.
The current acid deposition critical loads in Guangdong, China were calculated using the PROFILE model with a 3 km × 3 km resolution. Calculations were carried out for critical loads of potential acidity, actual acidity, sulfur and nitrogen, with values in extents of 0–3.5, 0–14.0, 0–26.0 and 0–3.5 kmol/(hm2·year), respectively. These values were comparable to previously reported results and reflected the influences of vegetation and soil characteristics on the soil acid buffering capacity. Simulations of S...  相似文献   
63.
Wildlife-road conflict has profound negative impacts on both wildlife populations and society. Despite a long-held understanding of this problem, in most regions the wildlife-management strategies (WMS) available to mitigate this conflict are still relatively underutilized. This study examines the implementation of these strategies into road infrastructure, using Southern Ontario as a case study, in order to develop an understanding of what leads to successful WMS implementation. The project management concept of critical success factors was applied and interviews with project decision-makers and key stakeholders were conducted. Nine factors were identified and a comparison between a ‘smooth’ and ‘rough’ project is used to illustrate the cumulative effects that these factors, and their interrelationships, have on project implementation success. Practitioners can use these findings to evaluate WMS projects based on likelihood of success and allocate resources accordingly, ultimately leading to increased chances of implementation and overall benefit to conservation and society.  相似文献   
64.
In the spring and summer of 2017, communities along the Lake Ontario shoreline suffered from the worst flood event on record. In late May, daily water levels reached their highest point in over 100 years, and flooding continued throughout much of the summer as lake levels slowly declined, with inundation and erosion significantly impacting shoreline homes and businesses. In this work, we present results from a rapid response online survey of property owners along the New York Lake Ontario shoreline to quantify the perceived flood impacts of the 2017 extended high water event. The survey focused on the degree and spatial distribution of inundation and erosion; the duration and drivers of inundation; the associated damages to different property features, with an emphasis on shoreline protection; and the degree of disruption to business and other activities and services. Photographic documentation of inundation extent and property damage also was provided by survey respondents. We demonstrate the potential utility of this dataset by characterizing key features of inundation and erosion impacts across the shoreline, and by using classification and regression trees to explore the predictability of inundation and erosion based on property characteristics. This work is part of a larger effort to develop models of inundation and erosion that can support flood impact assessments across the shoreline and help communities better prepare for future extended high water events.  相似文献   
65.
珠江三角洲新垦大气核化速率研究   总被引:1,自引:1,他引:0  
计算了珠江三角洲新垦地区的大气核化速率,对核化机制及核化速率计算的影响因素进行了分析. 基于PRIDE-PRD2004观测实验期间新垦站点的气溶胶数浓度谱分布观测数据,计算出3 nm粒子的表观形成速率. 根据表观形成速率与核化速率之间的关系式,分析了1 nm粒径临界核的大气核化速率. 结果表明,新粒子事件期间3 nm粒子的表观形成速率为7.2~9.4 cm-3·s-1,1 nm临界核的大气核化速率为7.65×102~1.14×105 cm-3,与前体物硫酸蒸气浓度比较一致,气态硫酸应是主要的核化前体物. 新垦地区背景气溶胶中积聚模态对碰并汇贡献较大,事件期间气溶胶数浓度变化对核化速率计算结果影响不大. 本研究获取了新垦核化速率信息,有助于进一步了解核化机制. 由于成核临界粒径的不确定性对核化速率计算结果影响很大,确定成核临界粒径对核化速率计算十分重要.  相似文献   
66.
应用简单质量平衡法计算酸沉降临界负荷的研究   总被引:3,自引:1,他引:2  
基于植物响应、土壤稳定性,铝浓度,碱度和pH标准,应用简单质量平衡法计算红壤各种土的酸沉降临界负荷。结果表明,沙质红泥土,红沙土,潮沙土、中度侵蚀红壤和潮沙泥土的酸沉降临界负荷较低,棕泥土和红壤土较大;  相似文献   
67.
络合萃取法处理含酚废水技术经济分析   总被引:9,自引:3,他引:6  
从技术经济角度对络合萃取法处理含酚废水进行了分析,建立了投资及净现值与处理量和浓度的关系式。结果表明:络合萃取法投资及净现值指标对处理理敏感,而对浓度不敏感;  相似文献   
68.
报道在正常生产情况下,用环境监测仪测定锆英石及锆英釉料瓷砖的放射性水平。锆英石的总比放射性大于7.0×10~4Bq·kg~(-1),属放射性物质;锆英釉料瓷砖的γ、β放射性污染致公众的附加年剂量当量为0.34mSv,相当于公众剂量限值的1/3。  相似文献   
69.
临界区甲醇的聚碳酸酯降解研究   总被引:2,自引:0,他引:2  
在间歇高压反应器中研究了聚碳酸酯在甲醇临界区域的降解行为 .降解无需借助催化剂 ,降解温度 2 2 0— 2 6 0℃ ,压力5 2 0— 8 6 7MPa ,时间 5— 4 5min ,通过GC MS与GC FID对液相产物进行了定性和定量分析 ,聚碳酸酯醇解主要产物为碳酸二甲酯 (DMC)和双酚A(BPA) .降解温度和时间为 2 4 0℃和 30min时 ,DMC和BPA的产率分别 91 75 %和 90 0 3% .通过凝胶渗透色谱 (GPC)对 2 4 0℃醇解反应的固相聚合物进行了分析 .降解初期 ,聚合物大分子发生断裂 ,PC的数均分子量 (Mn)迅速下降 ,仅有少量DMC和BPA生成 ;降解的中间阶段 ,低聚物在降解产物中的比例快速增加 ,同时DMC与BPA相应增多 ,最终PC被完全分解 .  相似文献   
70.
Scientists in higher education institutions around the globe recognize the importance of engaging with public stakeholders to share their enthusiasm, explain their science, and encourage primary and secondary students to enter the sciences. However, without direct consideration of students’ and teachers’ perspectives and interests, scientists may design activities around their own goals, limiting the impact on school stakeholders (i.e., students, teachers, paraprofessional staff, students’ parents, and other caregivers). We drew from natural and social science research to describe how expanding the conception of place beyond the biophysical can help engage school stakeholders in meaningful ways. We describe the multidimensional PLACE framework that we developed to integrate perspectives, knowledge, and values of all stakeholders in engagement programming. The framework is organized around topics that stakeholders should discuss early on to ensure successful partnerships. We recommend that scientists identify and use pedagogy that is inclusive; language framed around dialogic communication methods; aims and motivations centered on engagement; cultural funds of knowledge of place (i.e., disciplinary, personal, or experiential knowledge); and evaluation of engagement based on meaningful metrics. Two case studies are presented to illustrate how the PLACE framework components, when addressed, can lead to robust, successful partnerships between scientists and schools.  相似文献   
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