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111.
植物入侵是河口湿地土壤碳(C)、氮(N)、磷(P)循环的主要驱动因素.为了探讨福建闽江河口互花米草入侵短叶茳芏湿地对碳输入和 碳排放的影响,对土壤C、N、P含量和储量及CH4和CO2排放进行了测定与分析.结果表明:①互花米草入侵短叶茳芏湿地显著增加了0~60 cm土壤C、N含量和0~15 cm土壤P含量(p<0.05).②互花米草入侵短叶茳芏湿地后,0~60 cm土壤C、N、P储量分别增加了16%、46%、26%(p<0.05).③互花米草入侵短叶茳芏湿地后,0~15 cm和15~30 cm土壤C/N显著降低了33%和24%,15~30 cm土壤C/P降低了31%(p<0.05).④互花米草入侵短叶茳芏湿地显著增加了CH4和CO2平均和累积排放(p<0.05).⑤土壤C、N、P与土壤CO2和CH4排放呈显著正相关(p<0.05,p<0.01),微生物生物量碳(MBC)与土壤CH4排放呈显著正相关(p<0.01),土壤C/N与土壤CH4排放呈显著负相关(p<0.05).综合来看,互花米草入侵闽江 河口短叶茳芏湿地增强了土壤C、N、P的固持和CH4、CO2的排放,并受到生态化学计量比的调节.本研究拓展了对植物入侵情形下河口湿地 生物地球化学循环的认知.  相似文献   
112.
以长春伊通河河谷阶地上部的农田土为研究对象,选用铁离子作为氮转化的一种影响因素,定性研究了不同浓度的铁离子对硝态氮、亚硝态氮、铵态氮三氮的变化影响。并且在建立方程组之后计算平衡常数,证明了铁的氧化作用,与实验所得相符合:铁促进铵态氮的吸附、促进硝化反应的进行。从实验和理论的角度说明了铁在三氮转化中起的作用,为进一步研究锰铁离子对氮转化的定量影响和氮素污染地下水的预测和定量评价提供科学依据。  相似文献   
113.
基于嵌套网格空气质量预报模式(NAQPMS)及耦合的污染来源追踪模块模拟2017年12月16日至2018年1月3日成渝地区一次区域重污染过程,定量解析成渝地区主要城市PM2.5来源,评估过程中应急减排的成效。结果表明,天气静稳和风向辐合是造成此次重污染过程的重要因素,污染峰值阶段,成渝地区多个城市PM2.5日均质量浓度超过150μg/m3,达到重度污染级别。污染过程中,成都市PM2.5本地排放的贡献率为42%,眉山和德阳贡献率将近30%;重庆市PM2.5本地排放的贡献率为60%,外来输送以湖北、湖南和其他地区为主,贡献率为24%,成都和重庆市的工业源和交通源的贡献最大。区域联防联控应急减排对成渝各城市空气质量改善效果显著,成渝地区PM2.5浓度降低率为5%~11%,对于未实施应急预警方案的地区(如眉山市)受周边城市减排影响,浓度降低可达6%。  相似文献   
114.
Heat stress on workers working outdoors in the power industry may result in fatigue and deterioration in task performance. This research collected and analyzed data on task performance of workers working indoors and outdoors with and without a cooling suit. The task performance was compared on the basis of heart rate, oxygen consumption, tympanic temperature, subjective responses, productivity, and error rates. Based on One-Way Analysis Of Variance (ANOVA) results, a significantly lower estimated working oxygen consumption was observed (p < .001) when the cooling suit was worn. The productivity was higher while workers wore the cooling suit as compared to no cooling suit (p = .011) whereas the error rates were significantly lower (p < .001). Also a significantly lower self-reported discomfort was observed in the neck and shoulders while working wearing the cooling suit (p = .004). This study concluded that wearing a cooling suit while working outdoors was associated with physiological benefits as well as improved task performance of the study participants.  相似文献   
115.
Variations in the chemical properties of landfill leachate   总被引:4,自引:0,他引:4  
Landfill leachates were collected and their chemical properties analyzed once every two months over a ten-month period from the Gin Drinkers' Bay (GDB) and Junk Bay (JB) landfills. The contents of solids, and inorganic and organic components fluctuated considerably with time. In general, the chemical properties of the two leachates correlated negatively (P<0.05) with the amounts of rainfall prior to the sampling periods. However, magnesium and pH of the leachates remained relatively constant with respect to sampling time. The JB leachate contained higher average contents of solids and inorganic and organic matter than those of GDB with the exception of trace metals. Trace metals were present in the two leachates in trace quantities (<1.0 mg/liter). The concentrations of average ammoniacal nitrogen were 1040 and 549 mg/liter, while chemical oxygen demand (COD) values were 767 and 695 mg/liter for JB and GDB leachates, respectively. These results suggest that the leachates need further treatment before they can be discharged to the coastal waters.  相似文献   
116.
According to the practice researching and formulating “The Oil Spill Contingency Plan of south Chinese Sea”,this paper analyses and discusses the structure,functions and main contents of marine oil spill contingency planning,programs the organizing and commanding system and emergency response system,and advances the planning and researching method to coordinate comprehensively and to design practically the detailed emergency response steps until to formulate the ease operating programs for the plan implementation(PPI) and the PPI to apply high-techniques supporting emergency administrations and response.  相似文献   
117.
利用环境容量进行环境影响评价   总被引:1,自引:0,他引:1  
为有效地控制环境污染,目前全国在环境管理过程中已经逐步实施了污染物总量控制,但是在环境影响评价中,却仍然是采用传统的评价方法——浓度控制法,即首先预测出拟建工程对环境所产生的污染物浓度贡献,然后与评价标准比对,如果超出了评价标准,就将污染浓度削减到评价标准之下即可。显然,这是不符合总量控制原则的。为此笔者提出了利用环境容量进行环境影响评价,经验证该评价方法,既符合总量控制又具有简单易行、操作性强、准确可靠等许多优点。  相似文献   
118.
Tris(4-chlorophenyl)methanol (TCPM) is a global contaminant of unknown origin that is structurally related to the endocrine modulating pesticides 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and Dicofol. Therefore, the potential reproductive toxic effects of TCPM were investigated in sexually mature male Sprague Dawley rats (n = 20) treated with 1.0, 10.0 or 100 ppm of TCPM mixed in the diet for 28 days. The calculated TCPM intake was 0.0, 0.1, 1.2 and 12.4 mg/kg/day, respectively. Serum concentrations of follicle stimulating hormone (FSH) in terminal blood samples were significantly (P < 0.02) elevated in the highest dose group compared to the controls. In contrast, dietary exposure to TCPM had no effect on circulating levels of luteinizing hormone (LH), testosterone (T) and the T/LH ratio. Incubation of MCF-7 cells with increasing concentrations of TCPM failed to either induce proliferation or to block the proliferative effect induced by estradiol indicating that TCPM is neither estrogenic or anti-estrogenic. Relative binding affinity studies using androgen receptors from the prostate revealed that TCPM has a binding affinity comparable to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), the principle metabolite of DDT. In addition, the calculated Ki (0.62 microM) for TCPM is lower than the reported Ki's for the antiandrogenic pesticides p,p'-DDE and vinclozolin. Although TCPM binds with the androgen receptor in vitro, the absence of both an effect on serum T levels and morphological changes in the testis suggests that the mechanism of action for elevated FSH levels seen in vivo may not involve an antiandrogenic effect of TCPM at the dose level used in this study. The no adverse effect level for reproductive effects of TCPM is 10 ppm which is equivalent to a calculated intake of 1.2 mg/kg/day.  相似文献   
119.
Sulphoxide, sulphone and mercapturic acid derivatives of isomeric tetrachlorobenzene were synthesized. These compounds and isomers of tetrachlorophenol were characterized by spectroscopic and chromatographic methods.  相似文献   
120.
During one to three consecutive periods of 2 weeks, broiler chickens (n = 108) received test dies to which different amount of PCBs (7 congeners) were added. The relationship between exposure time and accumulation of individual congeners in different chicken tissues, such as breast, thigh and abdominal fat tissue, was observed. In all tissues, the vast majority of the PCB accumulation occurred during the first 2 weeks of exposures. After that, PCB concentrations only increased in the abdominal fat tissue of the animals. The individual PCBs were distributed differently in the various tissues. While CBs 28, 118, 138, 153 and 180 accumulated in the chickens, CBs 52 and 101 were metabolized, but no methyl sulphone metabolites of these congeners could be detected. Our results provide information on the absorption, tissue distribution and biotransformation of the individual PCB congeners and confirm the structure-activity relationships for metabolism of PCBs in birds, which are different from those in fish or mammalian species.  相似文献   
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