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1.
通过分析底泥中微生物的酶活性以及污染物的释放规律,探讨了温度对河道底泥生物修复的影响.结果表明,底泥中微生物的脱氢酶、脲酶和磷酸酶的活性随着温度的升高而显著增大,但温度对纤维素酶的活性影响较小.4 ℃和10 ℃时底泥中污染物的释放量和微生物的酶活性均较低,水质较稳定;20~37 ℃时底泥中污染物的释放量明显增加,微生物的新陈代谢能力有较大提高,水体的自净能力较强.在各种因素的综合作用下,20~30 ℃是进行底泥生物修复的适宜环境温度.此外,当pH为9.0以及添加葡萄糖时,底泥中微生物均表现出较高的脱氢酶活性. 相似文献
2.
This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies). 相似文献
3.
The human-driven loss of biodiversity has numerous ecological, social, and economic impacts at the local and global levels, threatening important ecological functions and jeopardizing human well-being. In this perspective, we present an overview of how tropical defaunation—defined as the disappearance of fauna as a result of anthropogenic drivers such as hunting and habitat alteration in tropical forest ecosystems—is interlinked with four selected Sustainable Development Goals (SDGs). We discuss tropical defaunation related to nutrition and zero hunger (SDG 2), good health and well-being (SDG 3), climate action (SDG 13), and life on land (SDG 15). We propose a range of options on how to study defaunation in future research and how to address the ongoing tropical defaunation crisis, including but not limited to recent insights from policy, conservation management, and development practice. 相似文献
4.
This article focuses on the governing system of the mitigation of eutrophication in the Baltic Sea. Policies and measures of the Baltic Sea coastal countries, the macro--regional (HELCOM) level, and the level of the European Union are described and governance challenges explicated. We found that the main challenges at different governance levels include: differences between coastal countries in terms of environmental conditions including environmental awareness, overlaps of policies between different levels, the lack of adequate spatial and temporal specification of policies, and the lack of policy integration. To help to meet these challenges, we suggest closer involvement of stakeholders and the public, the improvement of the interplay of institutions, and the introduction of a “primus motor” for the governance of the mitigation of eutrophication in the Baltic Sea. 相似文献
5.
The increasing production and use of plastic in the Arabian Gulf combined with shipping and waste disposal practices, have increased the concentration of plastic particles on the sea's surface and beaches. The objective of this investigation was to provide an assessment of the abundance, distribution, potential sources and significance of industrial plastic on the western beaches of the United Arab Emirates on the Arabian Gulf and on the eastern beaches on the Gulf of Oman. The abundance of stranded plastic pellets was highly uneven. By early 1992 alarming levels of fresh plastic pellets were noticed on the Arabian Gulf beaches of the UAE. Large numbers of 25 kg sacks of white plastic spherules manufactured by (SABIC) in Jubail, Saudi Arabia were washed ashore. When compared to the west coast on the Arabian Gulf, the east coast on the Gulf of Oman exhibited much lower levels of plastic pellets. When compared to other parts of the world, the beaches of the UAE on the Arabian Gulf are considered to be heavily polluted with industrial plastic. 相似文献
6.
In the present study, the endocrine activity of the antiepileptic pharmaceutical carbamazepine (CBZ) in the crustacean Daphnia magna was assessed. To assess the hormonal activity of the drug, we exposed maternal daphnids and embryos to environmental relevant concentrations of CBZ (ranging from 10 to 200 μg/L) and to mixtures of CBZ with fenoxycarb (FEN; 1 μg/L). Chronic exposure to CBZ significantly decreased the reproductive output and the number of molts of D. magna at 200 μg/L. This compound induced the production of male offspring (12?±?1.7 %), in a non-concentration-dependent manner, acting as a weak juvenile hormone analog. Results showed that this substance, at tested concentrations, did not antagonize the juvenoid action of FEN. Further, CBZ has shown to be toxic to daphnid embryos through maternal exposure interfering with their normal gastrulation and organogenesis stages but not producing direct embryo toxicity. These findings suggest that CBZ could act as an endocrine disruptor in D. magna as it decreases the reproductive output, interferes with sex determination, and causes development abnormality in offspring. Therefore, CBZ could directly affect the population sustainability. 相似文献
7.
Humic acid consists of a recalcitrant (unhydrolysed fraction) (the core) and labile (hydrolysable fraction) fraction. Core-humic acid (core-HA) isolation was performed by treating source material with apolar and polar solvents (organic solvents+acid hydrolysis) before alkaline extraction. Leonardite, soil Ah horizont and dry blood were chosen for this study because of their different origin and degree of humification. Chemical analysis (elemental analysis, total acidity, E(4):E(6)), spectroscopic analysis (DRIFT and (1)H NMR), and complete mass balance were used to investigate the effect of purifying humic acids. The results obtained showed that purification produced a slight modification of Leonardite humic acids as was expected for these highly humified organic matrices. On the other hand, about 500 g kg(-1) of soil humic acids were lost by purification. The fractions lost mainly consisted of carbohydrates. Dry blood showed the presence of humic acids that contrasted with its origin, thus indicating the limitations of the common analytical methods used for HA extraction. Nevertheless, in practice, purification caused the complete disappearance (914 g kg(-1) of HA was lost) of these HAs. The results obtained in this work suggest that the HA fraction isolated (named core-HA) effectively represents the HA structure proposed by the existing literature, since the purification proposed was able to eliminate the adsorbed organic molecules (interference materials) coating the HA structure. 相似文献
8.
This study assesses the growth of the microalgae Nannochloris oculata in the presence of lindane and the ability of N. oculata to remove lindane from media. Algal biomass increased with 0.1 and 0.5 mg L ?1 of lindane, and lindane concentrations in the media decreased. N. oculata removed 73% and 68.2% of lindane in the 0.1 and 0.5 mg L ?1 media concentrations, respectively. Algal biomass decreased to the level of the control at lindane concentrations greater than 2.5 mg L ?1, probably due to toxicity. N. oculata removed lindane from the media at concentrations lower than 1.0 mg L ?1. Thus, N. oculata may be useful for lindane bioremediation in contaminated aquatic systems. 相似文献
9.
A study was made of the influence of the application of sewage sludge on the degradation of pesticides in the soil. Two kinds of sludge were used, with different characteristics, one from an urban treatment plant and one from a food processing plant. Three organophosphorus insecticides, fenitrothion, diazinon and dimethoate, were studied. The relative importance was determined of the chemical and biological degradation processes, which involved experiments on soil and sterile soil samples. A comparative study was also made of the degradation of pesticide residues and the evolution of the microbial population. The application of sludge seems to have a complex effect on the degradation of pesticides, determined by the bioavailability and biodegradability of their active ingredient. The biodegradation of pesticide residues brings about alterations in the microorganism population of the soil. 相似文献
10.
Pentachlorophenol, depending on the applied concentration, reduces the activity of some microorganisms, as measured by the iron reduction test. The test is more sensitive, if the procedures reported in literature are modified, including the use of glucose as a source of energy instead of yeast extract. 相似文献
12.
阐述了环境保护与党的执政能力建设的内在联系。论述了加强环境保护是增强“党的领导能力”的题中之意;加强环境保护是“坚持把发展作为党执政兴国的第一要务,不断提高驾驭社会主义市场经济的能力”的重要内容;环境保护关系到社会和谐与国家安全。环境保护工作者应全面分析和妥善应对来自各方面的机遇和挑战,促使环境发展矛盾由“两难”向“双赢”转化,走生产发展、生活富裕、生态良好的文明发展之路。 相似文献
14.
Environmental Science and Pollution Research - Land use changes have led to the degradation of multiple ecosystem services and affected the quality of aquatic ecosystems. The aims of this study... 相似文献
16.
研究了热解终温对污泥热解残渣物理化学特性的影响,着重分析了不同热解终温下污泥热解残渣的比表面积、孔结构与吸附性能,并根据傅里叶红外光谱分析污泥热解残渣表面化学性质变化.研究表明,与污泥干燥基相比,污泥热解残渣中的水分、挥发分含量较低,灰分和固定碳含量较高;热解终温为500℃时,污泥热解残渣的总比表面积达到最大值20.1... 相似文献
17.
The data presented in this paper emphasize that the behavior and fate of pesticides in the environment is influenced by humic substances. Various methods most frequently used for the characterization of humic substances are discussed. Both humic acid and fulvic acid can solubilize in water certain organic compounds and are important carriers of some pesticides in soil. Humic substances have the potential for promoting the nonbiological degradation of many pesticides. Several methods of bleaching humus color from drinking water, including chlorination, ozonation, and UV-radiation, are described. Finally, the photochemical stability to UV-radiation of certain pesticides in aqueous fulvic acid solution is discussed. 相似文献
18.
Measurements of airborne gaseous ammonia and total dissolved ammonium in sea water determined on cruises on the North Sea have been used to calculate net fluxes of ammonia between air and sea. The system is finely balanced with the majority of net fluxes from air to sea, but some periods occur when the sea becomes a net source of ammonia in air. Examination of the field data suggests that the main factor determining the direction of flux is the airborne ammonia concentration, which when elevated causes ammonia deposition to the sea. It is calculated that ammonia deposition to the southern bight of the North Sea (below 56°N) amounts to 7.6 x 103 tonnes N per year, about one-half of an earlier upper limit estimate. Comparison with studies from the Pacific Ocean, in which the sea acts as a source of atmospheric ammonia, reveals that the major differences arise from much higher concentrations of airborne ammonia in the North Sea atmosphere caused by advection from adjacent land. 相似文献
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