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131.
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在中温(35℃±1℃)厌氧条件下,以葡萄糖为共基质,采用间歇实验方法,研究了2,6-二硝基酚(2,6-DNP)的厌氧产甲烷毒性和厌氧降解动力学.厌氧毒性试验(ATA)以累计产甲烷量和相对活性(RA)为指标,评价了不同浓度2,6-DNP对产甲烷菌的抑制程度;结果表明,2,6-DNP浓度<20 mg/L时,对产甲烷菌没有抑制作用,浓度为40 mg/L时产生轻度抑制,浓度为80~120 mg/L时产生重度抑制;24 h 2,6-DNP的75%、50%、25%相对抑制浓度分别为30、70和>120 mg/L.2,6-DNP降解动力学可用Haldane方程来描述,利用非线性拟合求得动力学参数Ks、Rm、Ki分别为179.7 mg/L、4.84 mg/g VSS·h、206.5 mg/L,方差R2=0.94,拟合效果很好. 相似文献
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Process of rice straw degradation and dynamic trend of pH by the microbial community MC1 总被引:7,自引:1,他引:6
LIU Jian-bin WANG Wei-dong YANG Hong-yan WANG Xiao-fen GAO Li-juan CUI Zong-jun 《环境科学学报(英文版)》2006,18(6):1142-1146
The process of the rice straw degradation in the fermentor with aeration at 290 ml/h was studied. The results of dissolved oxygen (DO) indicated that the optimum DO during cellulose degradation by microbial community MC1 ranged from 0.01 to 0.12 mg/L. The change model ofpH values was as follows: irrespective of the initial pH of the medium, pH values decreased rapidly to approximate 6.0 after being inoculated within 48 h when cellulose was strongly degraded, and then increased slowly to 8.0--9.0 until cellulose was degraded completely. During the degradation process, 15 kinds of organic compounds were checked out by GC-MS. Most of them were organic acids. Quantity analysis was carried out, and the maximum content compound was ethyl acetate which reached 13.56 g/L on the day 4. The cellulose degradation quantity and ratio analyses showed that less quantity (under batch fermentation conditions) and longer interval (under semi-fermentation conditions) of rice straw added to fermentation system were contributed to matching the change model of pH, and increasing the quantity and ratio of rice straw degradation during cellulose degrading process. The highest degradation ratio was observed under the condition office straw added one time every five days (under semi-fermentation conditions). 相似文献
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AbstractThe roles of PM2.5-induced mitochondrial damage and oxidative stress on mast cell degranulation were examined in vitro. Mast cells were treated with suspensions of PM2.5 in Dulbecco’s modified Eagle’s medium at concentrations from 25 to 200?mg/L in the absence or presence of 10?mmol/L N-acetyl-L-cysteine. Biological effects and mitochondrial function were assessed by determining cell viability, β-hexosaminidase release, interleukin-4 secretion, reactive oxygen species generation, adenosine triphosphate production, potential alteration of mitochondrial membrane, and activities of mitochondrial electron transport chain complexes I and III. Exposure of mast cells to PM2.5 induced reduction of adenosine triphosphate production, collapse of mitochondrial membrane potential, and inhibition of the activity of complex III. Co-treatment of mast cells exposed to PM2.5 with N-acetyl-L-cysteine attenuated cytotoxicity and the production of reactive oxygen species, and decreased the release of β-hexosaminidase and interleukin-4. Evidently, PM2.5-induced oxidative stress plays an essential role in mitochondrial toxicity and mast cell activation. 相似文献
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Mona Akbar Muhammad Farooq Saleem Khan Ling Qian Hui Wang 《Frontiers of Environmental Science & Engineering》2020,14(6):98
139.
Eco-Environmental Degradation in the Source Region of the Yellow River, Northeast Qinghai-Xizang Plateau 总被引:4,自引:0,他引:4
The Yellow River is the second longest river in China and the cradle of the Chinese civilization. The source region of the Yellow River is the most important water holding area for the Yellow River, about 49.2% of the whole runoff comes from this region. However, for the special location, it is a region with most fragile eco-environment in China as well. Eco-environmental degradation in the source region of the Yellow River has been a very serious ecological and socially economic problem. According to census data, historical documents and climatic information, during the last half century, especially the last 30 years, great changes have taken place in the eco-environment of this region. Such changes are mainly manifested in the temporal-spatial changes of water environment, deglaciation, permafrost reduction, vegetation degeneracy and desertification extent, which led to land capacity decreasing and river disconnecting. At present, desertification of the region is showing an accelerating tendency. This paper analyzes the present status of eco-environment degradation in this region supported by GIS and RS, as well as field investigation and indoor analysis, based on knowledge, multi-source data is gathered and the classification is worked out, deals with their natural and anthropogenic causes, and points out that in the last half century the desertification and environmental degradation of this region are mainly attributed to human activities under the background of regional climate changes. To halt further degradation of the environment of this region, great efforts should be made to use land resources rationally, develop advantages animal agriculture and protect the natural grassland. 相似文献
140.
Changes Of Hydrological Environment And Their Influences On Coastal Wetlands InThe Southern Laizhou Bay, China 总被引:2,自引:0,他引:2
The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore “red tides” happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area. 相似文献