乌江干流中上游水电梯级开发水温累积效应

以乌江流域洪家渡库尾至乌江渡坝下的水电工程干扰典型段为研究区域,利用建坝前后的水温实测资料,采用建坝前天然水温和建坝后下泄水温比较法,对乌江干流梯级水库水温时空分布特征进行分析。研究结果表明：对天然水温改变最大的电站为洪家渡和乌江渡,前者是受水库水温结构自身影响,后者是梯级联合运行的结果;梯级联合运行使库区水温分层有所减弱,随着时间的推移或上游梯级电站的建成,电站下泄水温年变化过程趋于均化,与天然水温的延迟也越加明显;不同的水库水温结构对水温累积效应的影响也各不相同,稳定分层型水库对水温累积具有正效应,混合型水库具有负效应,过渡型水库处于两者之间,体现了梯级电站的水温累积影响,为研究减缓下泄低温水的对策措施提供依据和参考。     

Ecological risk analysis of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Laizhou Bay

The current research aims at developing predictive models for trihalomethane (THM) formation in Lebanon based on field-scale investigations as well as laboratory controlled experimentations. Statistical analysis on field data revealed significant correlations for TTHM with chlorine dose, Specific UV-A, and UV(254) absorbing organics. Simulated distribution system-THM tests showed significant correlations with applied chlorine dose, total organic carbon, bromides, contact time, and temperature. Predictive models, formulated using multiple regression approaches, exhibiting the highest coefficients of determination were quadratic for the directly after chlorination (DAC; r(2) = 0.39, p < 0.036) and network (r(2) = 0.33, p < 0.064) THM databases, and logarithmic for the laboratory simulated THM database (r(2) = 0.70, p < 0.001). Computed r(2) values implied low correlations for the DAC and network THM database, and high correlation for the laboratory simulated THM database. Significance of the models were at the 0.05 level for DAC database, 0.10 level for the network database, and very high (<0.01 level) for the laboratory simulated THM database. It is noteworthy to mention that no previous attempts to assess, monitor, and predict THM concentrations in public drinking water have been reported for the country although a large fraction of the population consumes chlorinated public drinking water.     

现代企业安全管理信息系统的构建

论述现代企业安全管理信息系统的功能需求、基本框架、核心功能和系统特点。该系统把信息技术、网络技术及GIS应用到企业安全管理中,并融入安全学习志的管理理念,同时对基于联动机制的企业安全应急决策系统综合理论及其应用进行了研究。通过该系统的建立,使安全管理工作逐步走向科学化、系统化和规范化,对提高目前安全管理水平具有实际意义。     

Performance Criteria, Compliance Success, and Vegetation Development in Compensatory Mitigation Wetlands

The US Army Corps of Engineers often requires wetland creation or restoration as compensation for wetlands damaged during development. These wetlands are typically monitored postconstruction to determine the level of compliance with respect to site-specific performance standards. However, defining appropriate goals and measuring success of restorations has proven difficult. We reviewed monitoring information for 76 wetlands constructed between 1992 and 2002 to summarize the performance criteria used to measure progress, assess compliance with those criteria, and, finally, to evaluate the appropriateness of those criteria. Goals were overwhelmingly focused on plant communities. Attributes used to assess the quality of restored plant communities, including percent native species and the Floristic Quality Index, increased over time but were apparently unrelated to the number of species planted. Compliance frequencies varied depending on site goals; sites often failed to comply with criteria related to survival of planted vegetation or requirements that dominant plant species should not be exotic or weedy, whereas criteria related to the establishment of cover by vegetation or by wetland-dependent plants were often met. Judgment of a site’s success or failure was largely a function of the goals set for the site. Some performance criteria were too lenient to be of value in distinguishing failed from successful sites, whereas other criteria were unachievable without more intensive site management. More appropriate goals could be devised for restored wetlands by basing performance standards on past performance of similar restorations, identifying consistent temporal trends in attributes of restored sites, and using natural wetlands as references.     

Possible effects of persistent organochlorinated pollutants cocktail on thyroid hormone levels and pituitary-thyroid interrelations

In polluted district of Michalovce in East Slovakia (POLL) and two districts with background pollution (BCGR) 2046 adults (834 males and 1212 females aged 20-75 years) were examined. Serum levels of thyrotropin (TSH), free thyroxine (FT4), total triiodothyronine (TT3) and antithyroperoxidase antibodies (TPOab) were estimated by electrochemiluminiscent assay and also these of 15 polychlorinated biphenyl congeners (PCBs), p,p'-DDE, p,p'-DDT, hexachlorobenzene (HCB) and hexachlorocyclohexane were measured by high resolution gas chromatography/mass spectrometry. In addition, also dioxins, furans, coplanar- and mono-ortho-PCBs as well as selected hydroxylated and methylsulphonated PCBs and DDE metabolites were measured by appropriate methods based on gas chromatography/mass spectrometry principle. In POLL significantly higher levels of all organochlorines were found than these in BCGR. When pooled values from both areas were stratified in terms of PCBs level and treated as continuous variables, positive association of PCBs with FT4 and TT3 was found, the latter two being also mutually associated. However, within the category of PCBs level <530 ng/glipid (n=232) the association between PCBs and both the FT4 (p<0.09) and TT3 (p<0.03) was negative and any association of these was not found within the category of PCBs level of 531-1000 ng/g (n=691). In contrast, in the category of 531-2000 ng/g (n=1307) positive association appeared between PCBs and FT4 (p<0.001) as well as TT3 (p<0.05). Highly significant association of PCBs with FT4 (p<0.001) was further found in the categories with PCBs level of 1001-101414 ng/g (n=1307) and 2001-101414 (n=1123), while significant association with TT3 was observed only in the category of 531-2000 ng/g. Such findings suggest possible threshold level in positive effect of PCBs on FT4 and TT3 level which seems to be individual and located somewhere around the PCBs level of 1000 ng/g. However, highly significant negative association of both FT4 and TT3 with TSH was found in each of above indicated PCBs categories. Considerable difference in FT4 and TT3 level between large groups of subjects with the same range of PCBs level was also found suggesting different individual susceptibility to the effects of organochlorines. Among a total of 26 cases from POLL with very low TSH level (<0.5 mU l(-1)) 13 cases showed very high level of PCBs, FT4 and TT3, thus supporting a hypothesis on a novel sporadic form of high PCBs related peripheral subclinical hyperthyroidism possibly resulting from the long-term disruption of equilibrium between bound and free thyroxine in plasma by high PCBs level followed by a striking inhibition of TSH release from the pituitary.     

Maternal and cord serum exposure to PCB and DDE methyl sulfone metabolites in eastern Slovakia

Polychlorinated biphenyls (PCBs) were commercially produced between 1959 and 1984 in eastern Slovakia. Improper handling led to a highly contaminated local environment and high levels of PCBs in humans and wildlife in the Michalovce area. The aim of this study was to analyse serum for methylsulfonyl metabolites of PCB (MeSO(2)-PCBs) and DDE (3-MeSO(2)-DDE) in serum samples from pregnant women and in a selected number of paired cord blood samples to assess maternal sulfone levels and patterns, and transplacental transfer of these metabolites. The donating women were from two districts in eastern Slovakia. A liquid-liquid extraction method together with separation of substance groups and further clean-up on silica gel columns were applied prior to analysis by gas chromatography/mass spectrometry. 3-MeSO(2)-DDE was the major methyl sulfone in most of the samples followed by a yet not identified MeSO(2)-hexaCB, 4'-MeSO(2)-CB101, 4'-MeSO(2)-CB87 and 4-MeSO(2)-CB149. The women from the contaminated area had three times higher concentrations of the MeSO(2)-PCBs than women from the reference area. This is the first report on methyl sulfone metabolites of PCB and DDE in human cord serum. It is shown that these metabolites are transported through the placenta. The levels of MeSO(2)-PCBs in the maternal serum were about 1.5 times higher than in the corresponding cord serum on a lipid weight basis. For 3-MeSO(2)-DDE, the levels were about the same in maternal and cord serum. The difference in the maternal:cord ratio, comparing MeSO(2)-PCBs with 3-MeSO(2)-DDE might be due to differences in transport through the placenta caused by their different affinities for lipoproteins and plasma proteins.     

Study of high-frequency electromagnetic field effect on some somatic and neuro-behavioral characteristics in healthy and neurodefective mice

The effect of long-term exposure to high frequency electromagnetic field (HF EMF) on some somatic and neural characteristics was studied in neurodefective Lurcher mutant (+/Lc) and normal wild type mice (+/+). Both newborn and young adult (3 months) animals derived from two strains (C3H, B6CBA) were exposed to HF EMF (870 MHz) from 1st to 21st day or from 91st to 120th day respectively. In animals of both groups and controls we observed the development of body weight. Moreover, in the HF EMF exposed adult B6CBA animals we studied spatial learning ability, motor functions and the CNS excitability. To investigate specific energy absorption rate (SAR) in experimental animals we have done the basic 3D calculations of the electromagnetic energy distribution in the simplified model of the mouse. The HF EMF exposed animals exhibited mild differences of body weight between them and unexposed controls. The long-term exposure to HF EMF did not significantly influence the ability to learn in the Morris water maze. However, significant lower swimming speed was found in the irradiated +/Lc as well as lower motor activity of +/+ in the open field when compared to controls. No significant differences were found between HF EMF irradiated animals and controls in examination of the CNS excitability and motor functions.     

基于安全学习志的安全管理信息系统构建

通过分析论述安全学习志及安全管理信息系统的发展与特点,提出基于安全学习志安全管理信息系统的逻辑结构、总体构架和功能结构,以及从方法和技术角度为“安全学习志”在企业安全管理的应用提供一个全新的实现方案。本文把安全学习志这种理念融入到企业安全管理中,并对安全应急决策系统综合理论及安全管理信息系统建立技术方案的研究,目的在于为今后进一步的安全管理信息系统开发作理论和技术方法探索。     

GEO-SLOPE软件在某滑坡稳定性计算中的应用

以某滑坡为例,在充分分析其成因机制基础上,运用GEO-SLOPE软件对该滑坡的整体稳定性进行计算分析。结合室内试验、工程地质类比及参数反演确定稳定性计算参数,考虑到未来水库蓄水,在不同工况下对滑坡的稳定性进行计算,计算结果表明该滑坡的整体稳定性较好,只是在考虑地震作用的时候滑坡的整体稳定性迅速下降,甚至处于临稳状态。     

Supercritical fluid extraction of polycyclic aromatic hydrocarbons from white pine (Pinus strobus) needles and its implications

A supercritical fluid extraction (SFE) method was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) from fresh and fallen pine needles. Toluene-modified CO2 was used as the extracting fluid, and the extracted PAHs were analyzed by GC-MS. Using a two-stage extraction procedure, a static extraction at 180 degrees C and a dynamic extraction at 60 degrees C, and an in-cell silica gel plug plus a post-oven silica gel column, the extraction and fractionation of PAHs can be accomplished in one step. Over a seven month period, a significant variation was observed for PAHs in urban samples, while PAHs in mountain samples were at much lower levels (by a factor of approximately 8) and showed little seasonal change. Although dry fallen needles and fresh needles contained similar amounts of PAHs, in the fallen needles the lower molecular weight PAHs were partially lost while the higher molecular weight PAHs were slightly enriched. Pollution in urban areas was found to be highly localized, and buildings and trees are believed to be important factors in the restriction of atmospheric PAHs.