Impact of contaminants on aquatic systems and inundated sites with respect to flood events - In vitro biotests, chemical target analysis and fractionation methods

Scope of the present study is the development and application of aquatic in vitro bioassays and methods of effect-directed analysis (EDA). It aims at investigating contamination of suspended particulate matter (SPM) and pollution of inundated sites and riparian aquifer, respectively. In the first part of this study, SPM was sampled during flood events and toxicological activities were determined. The second part of the study dealt with possible conflict of interests between flood management (operation of retention basins) and drinking water supply (sustainment of water protection areas). Cytotoxic potencies were determined with the Neutral Red retention assay and dioxin-like and aryl hydrocarbon receptor mediated activities with the 7 ethoxyresorufin-o deethylase (EROD) assay, both using RTL W1 cells derived from rainbow trout (Oncorhynchus mykiss). Both bioassays indicated elevated potencies assoviated with SPM sampled during flood events. Highly active samples were fractionated in order to determine effective compounds. Strongly persistent compounds had an only minor contribution to total biological effects, whereas less persistent substances caused the bulk of biological activity. Chemical analysis showed that compounds analyzed with priority are not capable of adequately explaining the biological effects measured. Non-priority and a priori unknown compounds were mainly effective. The second part of the study aimed to investigate impacts of river contaminants to inundated sites and aquifer in flood events. For this end, the biotest battery was extended with the Ames Fluctuation assay and the bacterial tester strains TA98 and TA100 (Salmonella typhimurium) to detect mutagenic activity, as well as the Yeast Estrogen Screen (YES) assay with bakery yeast (Saccharomyces cerevisiae) to determine endocrine activity. Further, a recently developed method of effect-directed analysis (EDA) was used to separate more polar compounds in SPM and soil. Less persistent compounds were shown to be highly active. However, more polar compounds caused the highest effects. In accordance to findings of the first part of the study, chemical analysis showed that priority compounds only made a minor contribution to biological effects. River contaminant infiltration in the aquifer was assessed following a flood event with a recurrence interval of ten years by measurement of a tracer compound and hormonal activity. Both parameters indicated contamination of the aquifer following the flood. Water that was sampled in the hinterland showed delayed effects and, thus, indicated mass transport in groundwater layers over elevated distances. The findings of this study document high contamination of flood SPM that may be deposited at inundated sites. In particular, increased biological effects and chemical loads of more polar compounds indicate an increased impact of contaminant transfer through soil and aquifer contamination. Furthermore, infiltration and increased toxicological effects indicate a general risk of groundwater contamination in consequence of flood events. The results of the present study directly contribute to a manual assisting stakeholders and operators of retention basins and waterworks to a priori avoid potential conflict of interests and, thus, could directly be implemented in practical work

Получение желаемых передаточных функций импульсных систем автоматического управления

Рассмотрена задача получения желаемых передаточных функций импульсных систем автоматического управления. Предложен способ синтеза передаточных функций низкого порядка по прямым показателям качества, обеспечивающий конечное время переходного процесса

Occurrence and distribution of resistance to QoI fungicides in populations of Podosphaera fusca in south central Spain

Cucurbit powdery mildew caused by Podosphaera fusca limits crop production in Spain. Since its management is strongly dependent on chemicals, the rational design of control programmes requires a good understanding of the fungicide resistance phenomenon in field populations. Fifty single-spore isolates of P. fusca were tested for sensitivity to three quinone-outside inhibiting (QoI) fungicides: azoxystrobin, kresoxim-methyl and trifloxystrobin. Minimum inhibitory concentration (MIC) values for QoI-sensitive isolates were found to range from 0.25 to 10 μg ml−1 for azoxystrobin to 5–25 μg ml−1 for kresoxim-methyl, using a leaf disc-based bioassay. High levels of cross-resistance to QoI fungicides were found. Eleven isolates showed resistance to the three QoI fungicides tested with MIC and EC50 values >500 μg ml−1 resulting in RF values as high as >715 and >1000 for trifloxystrobin and azoxystrobin, respectively. A survey of P. fusca QoI resistance was carried out in different provinces located in the south central area of Spain during the cucurbit growing seasons in 2002, 2003 and 2004. Examination of a collection of 250 isolates for QoI resistance revealed that 32% were resistant to the three fungicides tested; the provinces of Ciudad Real, Córdoba and Murcia being the locations with the highest frequencies of resistance (44–74%). By contrast, no resistance was found in Badajoz, and relatively low frequencies were observed in Almería and Valencia (10–13%). Nearly 50% of resistant isolates were collected from melon plants. Based on these data, recommendations about the use of QoI fungicides for cucurbit powdery mildew management in the sampled areas are made.Estación Experimental “La Mayora” (CSIC), Algarrobo-Costa, E-29750 Málaga, Spain Grupo de Microbiología y Patología Vegetal-Unidad Asociada a CSIC, Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, SpainPeer reviewe

Spannungsfeld Hochwasserrückhaltung und Trinkwassergewinnung : ein Leitfaden

Viele Talauen sind sowohl für die Gewinnung von Trinkwasser aus Grundwasser, als auch für die Schaffung von Hochwasserrückhalteräumen geeignet. Im vorliegenden Leitfaden werden die Prozesse des Stofftransports von der fließenden Welle über den Retentionsraum bis zu den Entnahmebrunnen eines Wasserwerks vorgestellt. Es wird deren Einfluss auf ein höheres Risiko der Verunreinigung der Grundwasserressource durch den Eintrag von Schadstoffen aus den Retentionsräumen diskutiert

Разработка расчетных методов определения характеристик индустриальных масел

В ходе работы проанализированы характеристики индустриального масла марки И-20А, с использованием метода множественного регрессионного анализа разработаны расчетные способы определения характеристик индустриального масла, сделан вывод о точности разработанных методов, определены наиболее точные методы.In the course of the work, the characteristics of I-20A industrial oil were analyzed, using the multiple regression analysis method, calculation methods for determining the characteristics of industrial oil were developed, a conclusion was made on the accuracy of the developed methods, and the most accurate methods were determined

Evening Telegram, 1902-02-12

The Evening Telegram began publication in St. John's on 3 April 1879 and remains in print today under the title The Telegram. It was published daily except Sunday through to 1958, the frequency changing thereafter. -- The total collection has been split into several parts; this portion contains from 1900-1918