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91.
<正>Mercury is a global pollutant due to its widespread use,emission,and long-range transport(Blum,2013;Pacyna et al.,2010).It is considered a priority pollutant due to its neurological toxicity,persistence,and bioaccumulation(Pacyna et al.,2010;Sharma et al.,2015).Mercury pollution can occur when products that contain mercury are improperly disposed of and mercury is released into the air,water,and soil(Zhang and Wong,2007).An estimated 22%of the annual world usage of mercury is in electrical equipment such as batteries,thermometers,and discharge lamps,and electronic devices such as monitors and  相似文献   
92.
为了研究运动对2,3,7,8-四氯二苯并二恶英(2,3,7,8-TCDD)急性暴露大鼠肝组织酶活性的影响,将40只雄性Wistar大鼠随机分为正常对照组(NC)、染毒组(NT)、运动对照组(EC)、运动染毒组(ET)。染毒组(NT组与ET组)腹腔注射10μg·kg-1(以单位体重计)的TCDD,对照组(NC组与EC组)腹腔注射等量的玉米油;NT、NC组静养4周,ET、EC组运动(尾部负重5%游泳30分钟)4周。4周后,称重并宰杀大鼠,分离肝组织,称重后-80℃保存待测7-乙氧基异吩恶唑酮脱乙基酶(EROD)、7-乙氧基香豆素-O-脱乙基酶(ECOD)及芳香烃羟化酶(AHH)的活性。将数据进行多因素方差分析(MAVONA)处理,结果表明,染毒可降低大鼠体重,增加肝湿重和肝相对重量、增加EROD、ECOD活性;运动可增加大鼠肝相对重量、增加AHH的活性;染毒后运动可降低EROD、ECOD的活性。结论:急性10μg·kg-1(以单位体重计)TCDD染毒后4周可增加大鼠肝相对重量;4周的运动能有效降低TCDD对EROD、ECOD活性的激活作用。  相似文献   
93.
Plant invasions are a serious threat to natural and semi-natural ecosystems worldwide. Most management-orientated research on invasions focuses on invaders that are already widespread and often have major impacts. This paper deals with "emerging" invaders-those alien species with the potential to become important problems without timely intervention. A climate matching procedure was developed to define areas of South Africa, Lesotho and Swaziland that could be invaded by 28 plant species that had previously been classified as emerging invaders. Information on the location of populations of these species in the study area was combined with information on their distributions (as native or alien) in parts of Australia and the United States of America. These two countries had the best available distribution data for this study. They also share many invasive alien plant species with South Africa. Climatic data obtained for weather stations near points of known occurrence in these countries were used to define the climatically suitable areas for each species in the study area. Almost 80% of the remaining natural environment in southern Africa was found to be vulnerable to invasion by at least one of these species, 50% by six or more and 24% by 16 or more species. The most vulnerable areas are the highveld grasslands and the eastern escarpment. The emerging invaders with the greatest potential range included Acacia podalyriifolia and Cortaderia selloana. The globally important invaders Ulex europaeus and Lythrum salicaria had a more limited invasion potential but could still become major invaders. There was no relationship between the extent of the climatically suitable areas for the different species and an expert ranking of their invasion potential, emphasising the uncertainties inherent in making expert assessments based on very little information. The methods used in this analysis establish a protocol for future modelling exercises to assess the invasion potential of other emerging invaders.  相似文献   
94.
程飞鹏  杨冬亮  常乐  吴登峰 《环境科学》2022,43(12):5676-5686
以河南南部天然钙基膨润土为原料,通过钠化改性得到了钠基膨润土.通过调控吸附剂用量、亚甲基蓝(MB)浓度、吸附时间、溶液pH值和温度,分析对比了天然钙基膨润土(PRT-1)、钙基提纯膨润土(PRT-1T)和钠基膨润土(PRT-1Na)对MB的去除效率.同时,对PRT-1T和PRT-1Na对MB的吸附动力学和吸附机制进行了研究.结果表明,由于PRT-1Na有更大的比表面积、更高的阳离子交换容量和更丰富的羟基结构,表现出对MB更好的吸附效果.在同等吸附条件下,PRT-1Na的吸附效果是PRT-1的4倍,PRT-1T是PRT-1的2倍.在20℃,pH为6,PRT-1Na用量为1.0 g,吸附时间为2 h,MB为500 mL,且初始浓度为500 mg·L-1时,MB去除率高达99.89%.另外,PRT-1Na对MB染料废水的吸附既存在物理吸附也有化学吸附,Elovich模型对PRT-1T和PRT-1Na吸附MB染料废水的过程拟合度均高,但伪一级动力学模型对PRT-1Na拟合效果最好.  相似文献   
95.
Narrowing the decision space is crucial in water quality management at the meso-scale for developing countries, where a lack of data and financial budgets prevent the development of appropriate management plans and result in serious water quality degradation in many rivers. In this study, a framework for handling this task is proposed, comprising a lumped water quality model, with sensitivity and uncertainty analyses, and a management domain, including loss estimation and value of information analysis. Through a case study with linear alkylbenzene sulfonate (LAS) in the Yodo River, it is found that non-point sources and flow rate are factors that influence LAS concentration at the hot spot location. By considering the entire process of water quality management planning, we identify that the definition of the cost function of LAS treatment determines the appropriate estimation for the expected loss in reducing LAS under uncertain water quality conditions. The value of information analysis with “expected value of including uncertainty” and “expected value of perfect information” further helps estimate the benefit of including uncertainty in decision-making and the financial cost for obtaining more information regarding inputs that have been previously prioritized.  相似文献   
96.
Different water Acts (e.g., the European Water Framework Directive) and stakeholders involved in aquatic affairs have promoted integrated river basin management over recent decades. However, few studies have provided feedback on these policies. The aim of the current article is to fill this gap by exploring how local newspapers reflect the implementation of a broad public participation within a catchment of France known for its innovation with regard to this domain. The media coverage of a water management strategy in the Drôme watershed from 1981 to 2008 was investigated using a content analysis and a geographic information system. We sought to determine what public participation and decentralized decision-making can be in practice. The results showed that this policy was integrated because of its social perspective, the high number of involved stakeholders, the willingness to handle water issues, and the local scale suitable for participation. We emphasized the prominence of the watershed scale guaranteed by the local water authority. This area was also characterized by compromise, arrangements, and power dynamics on a fine scale. We examined the most politically engaged writings regarding water management, which topics of each group emphasized, and how the groups agreed and disagreed on issues based on their values and context. The temporal pattern of participation implementation was progressive but worked by fits and starts.  相似文献   
97.
Many countries are confronting climate change that threatens agricultural production and farmers’ lives. Farmers’ perceived risks of climate change and factors influencing those perceived risks are critical to their adaptive behavior and well-planned adaptation strategies. However, there is limited understanding of these issues. In this paper, we attempt to quantitatively measure farmers’ perceived risks of climate change and explore the influences of risk experience, information, belief in climate change, and trust in public adaptation to those perceived risks. Data are from structured interviews with 598 farmers in the Mekong Delta. The study shows that perceived risks to production, physical health, and income dimensions receive greater priority while farmers pay less attention to risks to happiness and social relationships. Experiences of the events that can be attributed to climate change increase farmers’ perceived risks. Information variables can increase or decrease perceived risks, depending on the sources of information. Farmers who believe that climate change is actually happening and influencing their family’s lives, perceive higher risks in most dimensions. Farmers who think that climate change is not their concern but the government’s, perceive lower risks to physical health, finance, and production. As to trust in public adaptation, farmers who believe that public adaptive measures are well co-ordinated, perceive lower risks to production and psychology. Interestingly, those who believe that the disaster warning system is working well, perceive higher risks to finance, production, and social relationships. Further attention is suggested for the quality, timing, and channels of information about climate change and adaptation.  相似文献   
98.
以沈阳2013—2015年臭氧(O_3)监测数据为基础,从地域差异及时间变化上分析了沈阳O_3浓度变化特征。结果表明:沈阳城市外围O_3浓度高于城市中心;O_3浓度变化具有明显季节特征,夏季O_3浓度最高,冬季最低;O_3浓度日变化呈单峰分布,谷值出现在06:00,峰值出现在14:00;O_3浓度出现明显"周末效应",周末白天O_3浓度高于工作日O_3浓度,夜间差异不大。  相似文献   
99.
To find a better composting process with low greenhouse gas emission and high humus production, the effect of adding kitchen waste on reduction and humification of organic matter during straw composting was studied. Three processes were compared, consisting of different ratios of straw and kitchen waste (1:2, 1:1, and 2:1). At four time points over a 62-d incubation, the reduction and humification of compost was evaluated by measuring the total mass, carbon content, and humic material content of the compost. Treatment 1 (straw/kitchen waste ratio of 1:2) reduced the total mass of compost the most. Treatment 2 (straw/kitchen waste ratio of 1:1) reduced the total carbon content the most, reflecting the highest emission of greenhouse gas. Treatment 3 produced the most humic acid material and released the lowest amount of carbon. Hence, from the point of view of reducing greenhouse gas emissions and increasing stable organic matter such as humus and humic acid during composting, treatment #3 was optimal. The three treatments resulted in significant differences in microbial biomass and enzyme activity during composting. The highest amount of active microbial biomass was associated with the largest reduction in compost mass (treatment 1). Higher proportions of straw (treatments 2 and 3), which contains more lignin, were associated with greater β-glycosidase activity, which may generate more humus that can improve soil quality. Dehydrogenase activity seemed to be the most important microbial factor in organic carbon catabolism or humification.  相似文献   
100.
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