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Toxicity Screening (toxicity + screening)
Selected AbstractsDirect toxicity assessment of wastewater: Baroxymeter, a portable rapid toxicity device and the industry perspectiveENVIRONMENTAL TOXICOLOGY, Issue 3 2002Achilles Tzoris Abstract Direct toxicity assessment of wastewater is becoming necessary, and new legislation may render it compulsory for the water industry. At present such assessment is performed at a laboratory away from a site, at considerable cost, and results often come too late, after a toxic event has occurred and the toxin has been released into the environment. Some of the rapid toxicity tests available today require certain conditions to function properly, or their results do not always correlate with other methods. The objective of this study was to assess a portable device, the Baroxymeter, for its suitability as an instrument to test wastewater toxicity. The way the device works is based on monitoring respiration of a bacterial culture by pressure measurements and using respiration inhibition as a toxicity alert. It has been shown that it is possible to detect toxic substances such as 3,5-dichlorophenol and bronopol within 5 min from a 1-mL sample. The benefits and future applications of the Baroxymeter as a high-throughput, cost-effective alternative for toxicity screening are discussed in this article. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 284,290, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10059 [source] Quick assessment of cytotoxins effect on Daphnia magna using in vivo fluorescence microscopyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2010Vera V. Teplova Abstract A novel approach to contaminant toxicity screening is proposed. The use of fluorescent microscopy with fluorescent dyes allows for assessing intoxication of Daphnia magna tissues, at various stages of exposure, to contaminants present in water. As shown, D. magna may not only be used as a test species in toxicity tests based on its lethality, but due to its translucency and application of fluorescent probes, separate steps of its intoxication and dying can be visualized. Using a variety of fluorescent probes, the present study also contributes to a better understanding of the toxicity mechanisms. Environ. Toxicol. Chem. 2010;29:1345,1348. © 2010 SETAC [source] Toxicological assessment of chemicals using Caenorhabditis elegans and optical oxygen respirometryENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2009Katherine Schouest Abstract Oxygen consumption is indicative of an organism's metabolic state, whereby alterations in respiration rate can result from the presence of different stimuli. Here, we develop a novel approach based on quenched fluorescence oxygen sensing and respirometry method for toxicity screening assays using the nematode Caenorhabditis elegans. Previously, C. elegans was established as a useful model in soil and aquatic toxicology studies. For existing toxicology screening approaches with C. elegans, however, the endpoint is lethality. In addition, the assay time frame for the existing approaches is considerably longer than that for the approach described here. We present a sensitive, robust, high-throughput platform using standard laboratory equipment for toxicological studies by measuring respiration rate in C. elegans animals using a phosphorescent probe. [source] Estrogenic endpoints in fish early life-stage tests: Luciferase and vitellogenin induction in estrogen-responsive transgenic zebrafishENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2006Rinus Bogers Abstract This study incorporated specific endpoints for estrogenic activity in the early life-stage (ELS) test, as described in Guideline 210 of the Organization for Economic Cooperation and Development and traditionally used for toxicity screening of chemicals. A transgenic zebrafish model expressing an estrogen receptor,mediated luciferase reporter gene was exposed to ethi-nylestradiol (EE2), and luciferase activity as well as vitellogenin (VTG) was measured. Concentrations of EE2 were tested at 1, 3, or 10 ng/L for 30 d from fertilization or during only the last 4 d with dimethylsulfoxide (DMSO) as presolvent (0.01%). Exposure to EE2 induced no toxic effects. Mean body weights were significantly higher in groups exposed for 30 d in the presence of DMSO, but condition factors were not affected. Significant luciferase and VTG induction occurred following 30-d exposure (3 and 10 ng EE2/L), while only VTG levels were affected in the 4-d exposure (10 ng EE2/L). This study demonstrated the usefulness of incorporating estrogenic endpoints in the OECD ELS test, fitting the requirements for screening estrogenic activity of chemicals. Quantitative measurement of both VTG and luciferase activity proved to be rapid and sensitive. Additional value of using transgenic zebrafish lies in combining VTG measurement with the more mechanistic approach of luciferase induction in one experiment. [source] Bioluminescence inhibition assays for toxicity screening of wood extractives and biocides in paper mill process watersENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Anna Rigol Abstract The risk associated with wood extractives, biocides, and other additives in pulp and paper mill effluents was evaluated by performing a characterization of process waters and effluents in terms of toxicity and chemical analysis. The individual toxicity of 10 resin acids, two unsaturated fatty acids, and three biocides was estimated by measuring the bioluminescence inhibition with a ToxAlert® 100 system. Median effective concentration values (EC50) of 4.3 to 17.9, 1.2 to 1.5, and 0.022 to 0.50 mg/L were obtained, respectively. Mixtures of these three families of compounds showed antagonistic effects. Chemical analysis of process waters was performed by liquid chromatography-and gas chromatography-mass spectrometry. Biocides such as 2-(thiocyanome-thylthio)-benzotiazole (TCMTB) (EC50 = 0.022 mg/L) and 2,2-dibromo-3-nitrilpropionamide (DBNPA) (EC50 = 0.50 mg/L) were the most toxic compounds tested and were detected at concentrations of 16 and 59 ,g/L, respectively, in a closed-circuit recycling paper mill. Process waters from kraft pulp mills, printing paper mills, and packing board paper mills showed the highest concentration of resin acids (up to 400 ,g/L) and accounted for inhibition percentages up to 100%. Detergent degradation products such as nonylphenol (NP) and octylphenol (OP) and the plasticizer bisphenol A (BPA) were also detected in the waters at levels of 0.6 to 10.6, 0.3 to 1.4, and 0.7 to 187 ,g/L, respectively. However, once these waters were biologically treated, the concentration of detected organic compounds diminished and the toxicity decreased in most cases to values of inhibition lower than 20%. [source] Acinetobacter bioreporter assessing heavy metals toxicityJOURNAL OF BASIC MICROBIOLOGY, Issue 5 2006Desouky Abd-El-Haleem Dr. This work was conducted to employ a whole cell-based biosensor to monitor toxicity of heavy metals in water and wastewater. An isolate of industrial wastewater bacterium, Acinetobacter sp. DF4, was genetically modified with lux reporter gene to create a novel bioluminescent bacterial strain, designated as DF4/PUTK2. This bioreporter can investigate the toxicity through light inhibition due to cell death or metabolic burden and the specific stress effects of the tested soluble materials simultaneously. The use of Acinetobacter DF4/PUTK2 as a bioluminescent reporter for heavy metal toxicity testing and for the application of wastewater treatment influent toxicity screening is presented in this study. Among eight heavy metals tested, the bioluminescence of DF4/PUTK2 was most sensitive to Zn, Cd, Fe, Co, Cr followed by Cu in order of decreasing sensitivity. The same pattern of sensitivity was observed when several contaminated water and wastewater effluents were assayed. This work suggested that luxCDABE -marked Acinetobacter bacterium DF4/PUTK2 can be used to bioassay the ecotoxicity of wastewater and effluent samples contaminated with heavy metals. Using this assay, it is possible to pre-select the more toxic samples for further chemical analysis and to discard wastewater samples with low or no inhibition because they are not toxic to the environment. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||