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331.
The contents of 137Cs in the soil, plant, and animal samples collected in the ecosystems of protected areas from the White Sea to the Black Sea in 1999 slightly differ from those in the period between 1980 and 1984. As a result of global fallout after the Chernobyl accident, the content of radioactive cesium in the soil has increased only on the territory of the Biological Station of Moscow State University at the White Sea, whereas that in the litter and plants has increased in virtually all areas studied. The isotope content in animals is actually equal to that recorded between 1980 and 1984. The mobility of 137Cs in the soil–plant link has increased, which may be due to fallout after the accident. The duration of a complete radionuclide cycle in ecosystems decreases from 10 half-life periods in northern regions to 2.5 half-life periods in the southern regions. The Chernobyl disaster has caused no significant changes in the global radioactive background in the European part of the Russian Federation.  相似文献   
332.
ABSTRACT: Bluegills were exposed for one hour to 0.2 or 2.3 mg/liter water soluble fraction (WSF) of JP-4 in a testing chamber designed to contain individual fish. A strain gage paddle was used to monitor activity. Whole body movement of individual fish did not change appreciably during exposure to either 0.2 or 2.3 mg/liter WSF-JP-4. Strength of pectoral fin movement, accounting for the majority of the fish behavior, increased in six of ten individuals exposed to 2.3 mg/liter WSF-JP-4. Pectoral fanning may be a useful parameter to indirectly assess water quality.  相似文献   
333.
A cooperative mangrove mapping project between the Ecuadorian Center for Remote Sensing (CLIRSEN) and the University of Delaware was begun in August 1982. The objectives of the project were to create historical maps of mangrove ecosystem extent and change, while transferring aerial photographic interpretation techniques to Ecuadorian personnel. The result of this cooperation was a series of three 125,000 scale maps of historical mangrove extent and change from 1966 to 1982 in the southern Gulf of Guayaquil. This multitemporal study showed a 16% decrease in mangrove extent and a 27% increase in shrimp pond development. If these rates of change prevail into the future, mangroves in Ecuador will reach parity with shrimp ponds in 1984 and completely disappear by mid-1990. Recognizing the significance of this loss to shellfish and fish production along the coast, Ecuadorian scientists at CLIRSEN have subsequently initiated a nationwide mangrove mapping program to create a historical base for future mangrove management strategies.  相似文献   
334.
工程旨在探讨生态复合塘作为污水处理工艺,以实现城乡污水处理的多元化与可持续性目标。文章以蓟县毛家峪长寿度假村为例,结合混凝沉淀池、污泥浓缩池、快速渗滤湿地、潜流湿地和表面流湿地等技术,从工艺设计及其关键设计参数出发,在防治系统堵塞、冰冻、油渍及渗漏的基础上,创造性地将人工湿地同绿化带相结合,解决了生态塘占地面积大的问题。工程的预期结果:该技术工艺设计可使出水达到城镇污水处理厂污染物排放标准(GB8978-2002)一类A级水平、农田灌溉和城乡杂用水的用水标准,各类污染物去除率分别为SS(mg/L)87.5%~96.7%,BOD5(mg/L)93.3%,COD(mg/L)61.5%~84.8%,TP(mg/L)50%~91.7%,NH3-N(mg/L)最高达87.5%。该设计实现了污水处理与绿化、节地的有机统一,可根据实际情况在机关、企事业单位和住宅小区推广应用。  相似文献   
335.
On the basis of Annals of Nature of the Prioksko-Terrasnyi Biosphere Reserve, its colonization by invasive mammal species and the current state of their populations have been analyzed. In the mammal fauna of the reserve, 13 out of 60 species can be classified as invasive. They differ in the degree of impact on the biota. The house mouse, Norway and black rats, and European bison have virtually no effect on natural ecosystems; the effect of the muskrat, raccoon dog, American mink, red and axis deer is insignificant; and that of stray dogs and Tartarian roe deer is considerable. The European beaver and wild boar play an environment-forming role. The impact of beaver activities is strong but local, whereas activities of wild boars put into question the very possibility of conservation and analysis of representative biosphere areas and biological diversity in the reserve.  相似文献   
336.
为了查明成都市城郊水产品中汞的安全性,分两次对成都郊区16个鱼塘进行调查采样,用微波消解-氢化物发生原子荧光光谱仪并参考国标方法,测定了鱼中汞的含量。研究结果显示,与国家食品卫生标准鱼肉中汞含量(300ng/g)相比,16个鱼塘四种鱼肉中汞含量均未超标;鱼中汞含量空间分布上呈现东部>西部>南部;鱼的内脏中汞含量高于鱼肉;不同鱼类相比,肉食性鱼类>杂食性鱼类>草食性鱼类,无鳞鱼类>有鳞鱼类,即鲶鱼>鲫鱼>鲤鱼>草鱼。与国内外其它地区相比,成都市城郊鱼中汞含量相对较低。  相似文献   
337.
Many studies have suggested various kinds of forest policies, management planning and practices to help forests adapt to climate change. These recommendations are often generic, based mostly on case studies from temperate countries and rarely from Africa. We argue that policy and management recommendations aimed at integrating adaptation into national forest policies and practices in Africa should start with an inventory and careful examination of existing policies and practices in order to understand the nature and extent of intervention required to influence the adaptation of forest ecosystems to climate change. This paper aims to contribute to closing this gap in knowledge detrimental to decision making through the review and analysis of current forest policies and practices in Burkina Faso and Ghana and highlighting elements that have the potential to influence the adaptation of forest ecosystems to climate change. The analysis revealed that adaptation (and mitigation) are not part of current forest policies in Burkina Faso and Ghana, but instead policies contain elements of risk management practices which are also relevant to the adaptation of forest ecosystems. Some of these elements are found in policies on the management of forest fires, forest genetic resources, non-timber resources, tree regeneration and silvicultural practices. To facilitate and enhance the management of these elements, a number of recommendations are suggested. Their implementation will require experienced and well-trained forestry personnel, financial resources, socio-cultural and political dimensions, and the political will of decision makers to act appropriately by formulating necessary policies and mainstreaming adaptation into forest policy and management planning.  相似文献   
338.
目前富营养化评价方法众多,但各评价方法之间缺乏可比性,不利于湖泊富营养化的有效管理和治理.本文在对现有湖泊富营养化的评价方法进行分析、评价的基础上,从湖泊水生生态系统出发,提出了适合我国国情的基于<地表水环境质量标准>(GB3838-2002)的湖泊富营养化水生生态系统评价方法.即水质、水生生物与底质评价相结合的系统的、综合的富营养化评价方法.该方法可对不同湖泊的富营养化状况进行比较,并可对同一湖泊富营养化的时空变化进行分析,有利于对湖泊富营养化程度、成因做出客观、合理的判断,为治理富营养化提供全面、科学的决策依据.  相似文献   
339.
针对2005年11月14日吉林发生的松花江污染,采用鱼体血液指标进行了分析,结果发现污染物对鲤鱼血液高铁蛋白浓度影响显著,并探讨了此方法需注意的问题。  相似文献   
340.
利用气相色谱(GC-ECD)方法对珠江口水、沉积物及水生动物体内六六六(HCHs)和滴滴涕(DDTs)的污染现状进行了调查,并对该类污染物在水体多介质中的转移分配规律及对水生态环境安全的影响作了初步研究.结果表明,珠江口表层水中HCHs总量检出范围为1.12~8·91ng·L-1,平均值为4.25ng·L-1;;DDTs总量检出范围为2.61~16.86ng·L-1,平均值为7.66ng·L-1.表层沉积物(以干重计)中HCHs总量检出范围2.51~4.75ng·g-1,平均值为3.61ng·g-1;;DDTs总量检出范围为3.01~6.24ng·g-1平均值为4.33ng·g-1.水生动物中河蚬体内的HCHs和DDTs含量最高,分别为44.49和122.62ng·g-1;;虾类次之,为41.04和82.27ng·g-1;;鱼类最低,平均值分别为27.95和65.43ng·g-1.同国内外其他地区河流比较,珠江口水体和底泥中的HCHs和DDTs污染程度较低,但仍具有一定的潜在生态风险.林丹、三氯杀螨醇取代工业生产HCHs、DDTs,成为该水域有机氯污染的重要来源.  相似文献   
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