Multi-generation studies with Chironomus riparius--effects of low tributyltin concentrations on life history parameters and genetic diversity

While toxicological data are available for numerous chemicals from standard tests, little is known on effects of pollutants over several generations or regarding chronic effects of chemicals on genetic diversity. Within the experiments, effects of the model pollutant tributyltin (TBT) were investigated over eleven generations at a sublethal TBT concentration of 4.46 μg as Sn kg⁻¹ sediment dw on life-cycle parameters and genetic variability of Chironomus riparius. Moreover, the adaptation potential towards TBT was determined. This experimental design enables the identification of TBT effects on life-cycle parameters and the determination of a potential extinction risk caused by chronic exposure. Furthermore, effects on the genetic structure can be determined, which are not predictable based solely on knowledge of the toxic mode of action of the chemical.

Genetic variety was determined via microsatellite analysis, measuring individual length differences of highly variable satellite DNA fragments. For the identification of changes in tolerances towards the stressor, acute and chronic toxicity experiments were conducted.

During the multi-generation study, significant effects on development and reproduction were determined. For some generations, the emergence was significantly (p < 0.05) delayed under TBT exposure. Reproduction seems to be a sensitive parameter as well, whereby females laid significantly larger egg masses (p < 0.05) in the latter generations. TBT did not affect the population growth rate nor the genetic variability, while clear deviations from the Hardy–Weinberg equilibrium appeared. The study also provides strong evidence for the acquirement of a higher tolerance towards the stressor in the TBT-exposed group.     

我国道路交通信号控制机认证框架体系探讨

针对目前我国道路交通信号控制机产品存在的质量问题,对信号机生产企业进行深入调研,详细分析信号机发展现状、国内外产品认证制度及信号机强制检测制度等,并结合我国交通信号机产品自身的特点和实际,参考国外产品认证模式、认证流程,提出我国信号机产品以型式试验、初始工厂检查和获证后监督为模式的认证框架体系。信号机产品质量认证框架体系的建立,对提高产品质量,规范行业生产,将发挥积极的促进作用,同时也为我国交通安全产品的质量控制提供了新思路。     

Australian junior exploration floats, 2001–06, and their implications for IPOs

An analysis of 179 junior exploration floats, listed on the Australian Securities Exchange (ASX) between July 2001 and June 2006, helped to build a basic understanding of the strategy and business structure of these companies. The “typical” junior explorer raised A$4 million at initial public offering (IPO) to finance a 2-year, mainly greenfields exploration program. The capital raised at IPO entitled its investors to approximately half of the company, with the balance in the hands of the promoters, vendors and/or seed capital investors. Of the A$4 million raised at IPO, it intended to spend approximately two-thirds on exploration, while the remainder was absorbed in corporate overheads and the costs of the IPO. Once these were paid, ongoing corporate overheads averaged approximately 28% of its total operational expenditure. However, given an average total annual expenditure of approximately A$2.6 million, most juniors held insufficient capital reserves to meet operational costs beyond a time frame of 2 years. As at October 2006, 9% of the companies were in the process of mine construction, whereas 6% had made it to producer status. The lead time from listing to production ranged from 1.5 to 53 months, giving a median of 28 months.     

A contaminated site investigation: comparison of information gained from geophysical measurements and hydrogeological modeling

The investigation of contaminated sites is usually a long and expensive process. It is therefore desirable to use a combination of methodologies in an integrative approach that can reduce redundant information gathering. The objective of this study was to examine the usefulness of 2 non-intrusive exploration techniques in a contaminated site investigation. Borehole positioning based on geophysical measurements was compared to positioning based on the Bayesian expert system for flow-field modeling. The goal set at the field site was the assessment of the type and load of contaminants transported from the landfill site to the adjacent aquifer and the extent of leachate plumes within the groundwater. The two methods made different demands on information gathering and were found to be complementary. The geophysical approach focused attention on the waste compartments at the site and on mixing plumes in the adjacent aquifer but could not, without prior information, provided information on the flow field. The Bayesian approach to flow-field modeling determined areas of greatest model uncertainty at the model boundaries. The model highlighted areas of greatest uncertainty that might otherwise have been overlooked and provided information on the most likely mean direction of the leachate plumes. It was concluded that both methods contribute to a site investigation and should be used before additional drilling is carried out.     

石油勘探环境风险评价

通过对石油勘探开发过程中可能发生的环境风险进行识别和分析,提出了预防环境风险的方法和对策。为最大限度地降低风险,防止企业人员伤害、财产损失及环境破坏确定了管理目标,是石油企业实施HSE管理的一项重要内容。     

严格监督管理,减少环境污染──廊坊市环保局开展油田环境保护工作纪实

廊坊市环境保护局认真贯彻落实《河北省陆上石油勘探开发环境保护管理办法》,对石油企业勘探开发生产过程实施较全面的环境监督管理工作,督促石油企业积极采取措施减少和治理污染,有效地遏制了石油勘探开发生产过程中所产生的污染对生态环境造成的破坏和影响,使廊坊地区的生态环境明显转好。     

环境空气质量评价的普适指数公式

在适当设定空气污染物的基准值和用相对于基准值的空气污染物的“相对”值情况下,采用S型曲线表示空气污染物对环境空气质量的危害程度,并应用遗传算法优化公式中的参数,得出了一个对多种空气污染物通用的环境空气质量评价的普适指数公式。借助于折衷型激励功效函数将单基污染物分指数加权为综合指数。该公式形式简单,容量计算、评价结果精度较高,且具有可比性。     

Monitoring and estimating the flow conditions and fish presence probability under various flow conditions at reach scale using genetic algorithms and kriging methods

The combination of current velocity and water depth influences stream flow conditions, and fish activities prefer particular flow conditions. This study develops a novel optimal flow classification method for identifying types of stream flow based on the current velocity and the water depth using a genetic algorithm. It is applied to the Datuan stream in northern Taiwan. Fish were sampled and their habitat investigated at the study site during the spring, summer, fall and winter of 2008-2009. The current velocity, water depth and maps of the presence probability of fish were estimated by ordinary and indicator kriging. The optimal classification results were compared with the classification results obtained using the Froude number and empirical methods. The flow classification results demonstrate that the proposed optimal flow classification method that considers depth-velocity and optimally identified criteria for classifying flow types, yields a current velocity and water depth of 0.32 (m/s) and 0.29 (m), respectively, and classifies the flow conditions in the study area as pool, run, riffle and slack. The variography results of the current velocity and the water depth data reveal that seasonal flows are not spatially stationary among seasons in the study area. Kriging methods and a two-dimensional hydrodynamic model (River 2D) with empirical and optimal flow classification methods are more effective than the Froude number method in classifying flow conditions in the study area. The flow condition classifications and probability maps were generated by River 2D, ordinary kriging and indicator kriging, to quantify the flow conditions preferred by Sicyopterus japonicus in the study area. However, the proposed optimal classification method with kriging and River 2D is an effective alternative method for mapping flow conditions and determining the relationship between flow and the presence probability of target fish in support of stream restoration.