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511.
室内霉菌污染原因及其控制对策   总被引:3,自引:0,他引:3  
通过对建筑墙体内湿气迁移过程的研究,详细分析了霉菌污染产生的原因。通过夏、冬两季平均气候条件下沿墙厚度温度、相对湿度分布和湿积累量的具体计算,得出墙内的相对湿度将达到或超过70%,有时甚至处于饱和状态,从而为霉菌的生长提供了有利条件。基于分析结果,提出了对于室内霉菌污染的控制对策。  相似文献   
512.
Substance Flow Analysis (SFA) is an important instrument that allows for the undertaking of environmental management for a specific contaminant. 'Control Analysis' is a tool that assesses the effect on a target flow of changes in flows forming part of a control basis set. The purpose of the present study was to perform a modeling of the annual PCDD/F flows in Tarragona Province and to apply the model for human health risk assessment. The validation of the model has been evaluated by comparing estimated fluxes with experimental values. Eleven subsystems, as well as a set of 88 flows of the system in Tarragona Province were considered. The total PCDD/F accumulation in Tarragona Province was between 62.6 and 159.5 g I-TEQ/y. Accumulation in sediments (27.9-74.6 g I-TEQ/y) and soils (35.0-80.8 g I-TEQ/y) are the two principal modes of deposition. Estimated flow in human adipose tissue means a mean intake of PCDD/F (via ingestion and inhalation) of 243 pg I-TEQ/person/day. The food chain pathway accounts for 99% of the total daily intake. As a result of the simulation, a 100% decrease in industrial emissions would cause a 1.7% reduction in the PCDD/F accumulation in humans. In turn, a 100% reduction of PCDD/Fs in the industrial waste waters would cause only an insignificant 0.1% decrease in the accumulation of PCDD/Fs in humans.  相似文献   
513.
固相微萃取是一种快速、简便、集萃取浓缩于一体的样品前处理技术,具有分析快速、灵敏度高、无需有机溶剂的优点.用固相微萃取-毛细管气相色谱分析水中甲醇、丙酮、异丙醇、乙醇、乙腈、丙烯腈,检出限可达0.003~0.03 mg/L.  相似文献   
514.
交联菌丝体吸附剂的制备及其对Cr^3+的吸附特性   总被引:1,自引:0,他引:1  
深入研究了交联菌丝体吸附剂的制备工艺及其对Cr^3+的吸附特性。交联菌丝体吸附剂制备工艺简单,但在制备过程中,活化剂NaOH和交联剂的用量对吸附特性影响较大。与纯菌丝体吸附剂相比,交联菌丝体吸附剂表观吸附容量提高48%,达到49.83mg/g(pH=2.53,水溶液中的Cr^3+浓度为600mg/L),同时其机械强度明显增强。交联菌丝体吸附剂对Cr^3+的吸附特点是将沉淀法与吸附法相结合,将沉淀与吸附两过程合二为一,从而简化了处理工艺,降低了处理成本。  相似文献   
515.
European walnut (Juglans regia) plants were grown in pots, on peat soil contaminated with lead (Pb), for four years. European walnut was chosen because it grows in Mediterranean climates, it yields a high biomass, and a fine quality wood. In the above ground parts Pb concentration was 1000 times lower than in roots: in 50 g roots there was 450 mg of Pb. Microanalysis of roots found in periderm more than 50% of the total root Pb. Pb L(III) EXAFS spectroscopy was performed on: root powder from Pb-exposed plants, Pb-impregnated cellulose and lignin. Comparison of plant material with lignin and cellulose helped to envisage a plant disposal strategy for Pb. This may consist in establishing links with large organic molecules, which are abundant constituents of cell walls. EXAFS spectroscopy evidenced the presence of Pb-O bindings within the ligno-cellulosic structure in roots. Lead was scantly conveyed to the shoots, giving to walnut plants an added asset in Pb phytostabilization.  相似文献   
516.
Lee CC  Chen HL  Su HJ  Guo YL  Liao PC 《Chemosphere》2005,59(10):1465-1474
The aim of this study was to evaluate the PCDD/Fs patterns in ambient air based on data information emitted from incinerator generated from ambient air measurements and those in serum. Four circular zones, namely A, B, C, and D, were identified based on simulated ambient annual average PCDD/Fs concentrations, from a selected municipal waste incinerator. Sixteen ambient samples were taken from the 4 circular zones across 4-seasons. Eighty-nine volunteers were recruited according to the demographic distribution within each zone. PCDD/Fs profiles were documented both for air and serum samples collected. Comparing to the congener patterns from ambient air and serum samples, we found that OCDD, OCDF, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF were the predominant groups among 17 congeners from both the ambient air and serum sample. And, factor analysis showed the distribution patterns of PCDD/Fs from ambient air and serum samples are almost identical across different zones, except for congener patterns of serum samples from residents in zone C. In addition, the average PCDD/Fs level significantly reduced for about 10 folds than those of the other three seasons when the incinerator was shut down in one of sampling periods. We might conclude that ambient air exposure was the most important contributor to PCDD/Fs levels in ambient air but not the single in serum. Therefore, another or more powerful source, such as occupational exposure, dietary intake or the consumption of local food, should be further investigated at the same time.  相似文献   
517.
The present study was intended to establish an inventory of PCDD/F emissions in Tarragona Province (Catalonia, NE Spain), as a preliminary phase in the development of a flow analysis of PCDD/Fs in this Province. In 1999, global PCDD/F emissions reached a value of 2.24 g I-TEQ/y, which means a density of 3.8 micrograms I-TEQ/inhabitant/y. The low amount of PCDD/Fs emitted to air by the only municipal solid waste incinerator in the Province (approximately 0.04% of the total) has been one of the most notable results. As a reflection of uncertainties in the estimates for individual sources, the 90th percentiles of PCDD/F releases for 1999 ranged up to 4.1 g I-TEQ/y.  相似文献   
518.
Six sediment cores were collected from Green Bay, Wisconsin, in order to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) by a chemical mass balance (CMB) model. The cores which were obtained in 1995 had total PAH concentrations between 8.04 and 0.460 ppm. 210Pb and 137Cs dating was used to determine historical trends of PAH inputs, and elemental carbon particle analysis was done to characterize particles from combustion of coal, wood and petroleum. The results show that coke burning, highway dust, and wood burning are likely sources of PAHs to Green Bay. The contribution of coke oven emissions (CB) for the Green Bay cores is in the range of 5 to 90%. The overall highway dust (HWY) contribution is between 5 and 70%. There is a maximum (approximately 67%) contribution of HWY around 1988 which is in agreement with the historical US petroleum consumption. The wood burning (WB) contribution is between 1 to 30%, except in core GB-A where a maximum (approximately 50%) is found around 1994. The average relative errors of measurement for x2 equal to the number of degrees of freedom, are 52.5, 56.2, 36.2, 52.3, and 42.8 (df = 3) for the Green Bay cores A, B, C, E, and F, respectively. The sums of the contribution factors are less than one, indicating gain of inert biological or other bulk material between source and receptor. The results of carbon particles for Green Bay core D show that coal, oil, and wood burning are consistent with the CMB modeling results.  相似文献   
519.
Predation risk is amongst the most pervasive selective pressures influencing behaviour and animals have been repeatedly shown to trade-off foraging success for safety. We examined the nature of this trade-off in cleaning symbioses amongst Caribbean coral reef fishes. We predicted that cleaning gobies (Elacatinus evelynae and Elacatinus prochilos) should prefer fish clients that pose a low risk of predation (e.g. herbivores) over clients that may have more ectoparasites but pose a higher risk (e.g. piscivores). Our field observations revealed that cleaners did clean preferentially client species with more parasites but predatory and non-predatory clients had similar ectoparasite loads. Despite the lack of a foraging advantage for inspecting predators, cleaners did not avoid risky clients. On the contrary, a larger proportion of visiting predators than non-predators was inspected, gobies initiated more interactions with predatory clients, and predators were attended to immediately upon arrival at cleaning stations. This preferential treatment of dangerous clients may allow the rapid identification of cleaners as non-prey item or may be due to the effect of predators on the rest of the cleaners’ clientele, which avoided cleaning stations whilst predators were present. Dealing with potentially risky clients may allow gobies to regain access to their main food source: non-predatory clients.  相似文献   
520.
The objective of this paper is to quantify and compare the loss functions of the standard two-stage design and its composite sample alternative in the context of multivariate soil sampling. The loss function is defined (conceptually) as the ratio of cost over information and measures design inefficiency. The efficiency of the design is the reciprocal of the loss function. The focus of this paper is twofold: (a) we define a measure of multivariate information using the Kullback–Leibler distance, and (b) we derive the variance-covariance structure for two soil sampling designs: a standard two-stage design and its composite sample counterpart. Randomness in the mass of soil samples is taken into account in both designs. A pilot study in Slovenia is used to demonstrate the calculations of the loss function and to compare the efficiency of the two designs. The results show that the composite sample design is more efficient than the two-stage design. The efficiency ratio is 1.3 for pH, 2.0 for C, 2.1 for N, and 2.5 for CEC. The multivariate efficiency ratio is 2.3. These ratios primarily reflect cost ratios; influence of the information is small.  相似文献   
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