Sensitivity limits and EC50 values of the Vibrio fischeri test for organic micropollutants in natural and spiked extracts from sediments

• Published in: Environmental toxicology and chemistry 1998-04, Vol.17 (4), p.655-661
• Main Authors: Salizzato, Michela, Bertato, Valentina, Pavoni, Bruno, Ghirardini, Anna Volpi, Ghetti, Pier Francesco
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Marine and brackish environment; Polychlorinated biphenyls; Polycyclic aromatic hydrocarbons; Sediment; Sulfur; Vibrio fischerei; Vibrio fischeri
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.5620170419

Chemical analyses and bioassays were used in conjunction to assess the quality of sediments of the Venice lagoon. Organic micropollutants (polycyclic aromatic hydrocarbons [PAHs] polychlorinated biphenyls [PCBs], and chlorinated pesticides) were extracted from sediment samples and analyzed by gas chromatography after fractionation into classes of compounds. The Vibrio fischeri test was used to assess the acute toxicity of sediment extracts. The test was applied to organic extracts before cleanup and to extracts purified from sulfur and fractionated into single classes of compounds. Extracts before purification were much more toxic than single fractions. In particular, sulfur was toxic to V. fischeri. For PAHs and PCBs the 50% effective concentration (EC50) and EC20 values were determined using natural and spiked extracts (EC50 = 0.5 μg/ml and 1.4 μg/ml, respectively; EC20 = 0.13 μg/ml and 0.17 μg/ml). Sensitivity limits of the method for these compounds were also estimated as was an EC50 value of elemental sulfur dissolved in ethanol (0.022 μg/ml). A mathematical model was used to fit the concentration–response data to a sigmoid curve.