Ecotoxic Effect of Photocatalytic Active Nanoparticles (TiO2) on Algae and Daphnids (8 pp)

Background, Aim and Scope Due to their large potential for manifold applications, the use of nanoparticles is of increasing importance. As large amounts of nanoparticles may reach the environment voluntarily or by accident, attention should be paid on the potential impacts on the environment. First studies on potential environmental effects of photocatalytic TiO2 nanoparticles have been performed on the basis of widely accepted, standardized test systems which originally had been developed for the characterization of chemicals. The methods were adapted to the special requirements of testing photocatalytic nanoparticles. Materials and Methods: Suspensions of two different nanoparticles were illuminated to induce their photocatalytic activity. For testing, the growth inhibition test with the green alga Desmodesmus subspicatus and the immobilization test with the daphnid Daphnia magna were selected and performed following the relevant guidelines (algae: ISO 8692, OECD 201, DIN 38412-33; daphnids: ISO 6341, OECD 202, DIN 38412-30). The guidelines were adapted to meet the special requirements for testing photocatalytic nanoparticles. Results: The results indicate that it is principally possible to determine the ecotoxicity of nanoparticles. It was shown that nanoparticles may have ecotoxicological effects which depend on the nature of the particles. Both products tested differ in their toxicity. Product 1 shows a clear concentration-effect curve in the test with algae (EC50: 44 mg/L). It could be proven that the observed toxicity was not caused by accompanying contaminants, since the toxic effect was comparable for the cleaned and the commercially available product. For product 2, no toxic effects were determined (maximum concentration: 50 mg/L). In the tests with daphnids, toxicity was observed for both products, although the concentration effect-curves were less pronounced. The two products differed in their toxicity; moreover, there was a difference in the toxicity of illuminated and non-illuminated products. Discussion: Both products differ in size and crystalline form, so that these parameters are assumed to contribute to the different toxicities. The concentration-effect curves for daphnids, which are less-pronounced than the curves obtained for algae, may be due to the different test organisms and/or the differing test designs. The increased toxicity of pre-illuminated particles in the tests with daphnids demonstrates that the photocatalytic activity of nanoparticles lasts for a period of time. Conclusions: The following conclusions can be drawn from the test results: (I) It is principally possible to determine the ecotoxicity of (photocatalytic) nanoparticles. Therefore, they can be assessed using methods comparable to the procedures applied for assessing soluble chemicals. - (II) Nanoparticles may exert ecotoxicological effects, which depend on the specific nanoparticle. - (III) Comparable to traditional chemicals, the ecotoxicity depends on the test organisms and their physiology. - (IV) The photocatalytic activity of nanoparticles lasts for a relevant period of time. Therefore, pre-illumination may be sufficient to detect a photocatalytic activity even by using test organisms which are not suitable for application in the pre-illumination-phase. Recommendations and Perspectives: First results are presented which indicate that the topic 'ecotoxicity and environmental effects of nanoparticles' should not be neglected. In testing photocatalytic nanoparticles, there are still many topics that need clarification or improvement, such as the cause for an observed toxicity, the improvement of the test design, the elaboration of a test battery and an assessment strategy. On the basis of optimized test systems, it will be possible to test nanoparticles systematically. If a potential risk by specific photocatalytic particles is known, a risk-benefit analysis can be performed and, if required, risk reducing measures can be taken.     

Total quality management and performance appraisal: an experimental study of process versus results and group versus individual approaches

This study investigated the effect of a process versus a results focus as well as a group versus individual‐based approach to performance appraisals. Four experimental conditions were investigated, with dependent variables of appraisal satisfaction, perceived accuracy of the performance appraisal, expectations of performance improvement, and actual performance. The results showed that a process focus appraisal had a more positive impact than an exclusively results‐oriented appraisal on ratee appraisal satisfaction, perceived appraisal accuracy, and expectations of performance improvement. Subjects receiving process appraisal feedback also showed a greater improvement in actual performance during a subsequent trial compared to subjects that did not receive process feedback. No differences were found between the group‐ and the individual‐based performance appraisal conditions. Implications of these findings for appraisal processes in general, and total quality initiatives in particular, are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Evaluating the efficiency of municipalities in collecting and processing municipal solid waste: A shared input DEA-model

This paper proposed an adjusted "shared-input" version of the popular efficiency measurement technique Data Envelopment Analysis (DEA) that enables evaluating municipality waste collection and processing performances in settings in which one input (waste costs) is shared among treatment efforts of multiple municipal solid waste fractions. The main advantage of this version of DEA is that it not only provides an estimate of the municipalities overall cost efficiency but also estimates of the municipalities' cost efficiency in the treatment of the different fractions of municipal solid waste (MSW). To illustrate the practical usefulness of the shared input DEA-model, we apply the model to data on 293 municipalities in Flanders, Belgium, for the year 2008.     

The use of technology to address patterns of risk among teenage drivers

INTRODUCTION: The crash risk of teens is high, with fatal crash rates of teen drivers higher than any other age group. New approaches to reduce teen traffic fatalities are clearly needed. METHOD: A possible approach to reduce the incidence of teen driver crashes and fatalities is through the use of vehicle-based intelligent driver support systems. To be most effective, the system should address the behaviors associated with an overwhelming number of teen fatal crashes: speed, low seatbelt use, and alcohol impairment. In-vehicle technology also offers an opportunity to address the issue of inexperience through enforcement of certain Graduated Driver's License provisions. RESULTS: To fully understand the capability of such technologies, there should be a concerted effort to further their development, and human factors testing should take place to understand their effects on the driver. IMPACT: If successfully implemented, a Teen Driver Support System (TDSS), such as the one described here, could significantly decrease the number of teens killed in traffic crashes.     

Environmentally Friendly Disposal Behaviour and Local Support Systems: Lessons from a metropolitan area

This paper describes some of the insights gained by the authors in the development of an approach for systemic sustainability analysis to arrive at sustainability indicators (SIs) for development. The paper describes the problems of perspective and mindset which such research involves, and the necessity to rethink both the purpose and content of SIs as well as taking into account the perspective of the researcher. The result represents a new perspective on the classification of SIs that serves to highlight one of the central difficulties encountered so far with these tools, namely their limited use in management and the setting of policy. We argue that this is due in large part to the nature of the SI frameworks created to date, even if carried out in a 'participative' mode. The framework itself is representative of a mindset or paradigm of understanding which, when applied as the sole device, we find less than adequate in achieving useful SIs. SIs arising from this mindset tend to be quantitative and explicit (clearly stated and with a defined methodology), while in practice most people's and institutions' use of SIs tends to be more qualitative and implicit ('understood' to apply in vaguer terms, with no defined methodology). These two paradigms or mindsets are represented here as the reductionist and the conversational : the first is characterised by quantitative and explicit indicators (or QNE* indicators); and the second is characterised by qualitative and implicit indicators (QLI* indicators). We suggest that what is required is far more research on the evolution and use of QLI* SIs (and the mindset which is necessary to develop them), in order to best appreciate how they can be hybridised with the QNE* group. The result may be termed 'multiple perspective' SIs. Este documento describe algunas de las ideas obtenidas por los autores en el desarrollo de un acercamiento por análisis de sostenimiento sistemático para llegar a los indicadores de sostenimiento (SIs) por desarrollo. El documento describe los problemas de perspectiva y patrones que dicha investigación involucra, y la necesidad de repensar tanto en el propósito como en el contenido de los SIs así como tambien toma en cuenta la perspectiva del investigador. El resultado representa una nueva perspectiva en la clasificación del los SIs la cual sirve para resaltar una de las dificultades centrales encontradas hasta ahora con estas herramientas; especificamente su limitado uso en el manejo y establecimiento de políticas. Nosotros argumentamos que ésto se debe en gran parte a la naturaleza de las estructuras de los SIs creadas hasta la fecha, incluso si se lleva a cabo en un modo 'participativo'. La estructura por si misma es representativa de un patron o paradigma de entendimiento el cual cuando es aplicado al esquema único encontramos menos adecuado alcanzar SIs útiles. Los SIs que surgen de este patrón tienden a ser cuantitativos y explícitos (claramente señalados y con una metodología definida), mientras que en la practica el uso de los SIs por parte de la mayoria de la personas e instituciones tiende a ser mas cualitativo e implicito ('entendido' a aplicar en terminos mas vagos, con metodología mas definida). Estos dos paradigmas o patrones son representados aquí como el reduccionista y el coloquial — uno es caracterizado por indicadores cuantitativos y explícitos (o indicadores QNE*), el otro por indicadores cualitativos e implícitos (QLI*) respectivamente. Nosotros sugerimos que lo que se requiere es mucha mas investigación en la evolución y uso de SIs de QLI* (y el patrón que es necesario para desarollarlo), para apreciar mejor como ellos pueden ser mezclados con el grupo de QNE*. El resultado puede ser denominado indicadores de sostenimiento de perspectiva multiple.     

1998年厄尔尼诺后珊瑚礁的侵蚀与恢复:印度洋查戈斯礁群

在印度洋中部查戈斯礁群的大多数珊瑚死亡之后3年,对30m水深以浅珊瑚的侵蚀和恢复情况进行了研究.北部环礁15m水深以浅、中部和南部环礁＞35m处的珊瑚差不多全部死亡.由于密集珊瑚丛的损失,一些礁体"表面"下降了1 5m.珊瑚的生物侵蚀情况严重,减少了三维礁体"结构"并形成松散的碎石.幼年珊瑚数量众多,尽管大部分是在侵蚀的或不稳定的基底上,并且稳定种较少.在15m的深度,礁体间鱼类丰度和多样性仍旧较高;依赖于珊瑚生存的物种减少,而一些食草动物和食碎屑动物则增加.一个新的海面温度(SST)数据集表明,平均SST自1950年以来升高了0.65℃.造成查戈斯珊瑚礁死亡的临界SST是29.9℃.