Alice Petre

Background, aim, and scope The high consumption of blood lipid regulators is leading to frequent reports of the occurrence of fibrates in natural streams and wastewater effluents. This paper describes a study undertaken to evaluate the acute toxicity of bezafibrate, clofibric acid, gemfibrozil, and fenofibric acid, a metabolite of fenofibrate whose ecotoxicity has not been previously reported. Materials and methods The bioassays used were based on Vibrio fischeri, Daphnia magna, and Anabaena CPB4337 tests. Anabaena CPB4337 is a novel bioassay based on Anabaena sp. PCC 7120 strain CPB4337 bearing in the chromosome a Tn5 derivative with luxCDABE from the luminescent terrestrial bacterium Photorhabdus luminescens. Results The higher toxicity corresponded to fenofibric acid, with EC50 as low as 1.72 mg/l for V. fischeri. Gemfibrozil was also toxic for Anabaena sp. with EC50 of 4.42 mg/l. The study reports the results from toxicity tests using fortified real wastewater samples taken from the effluent of a wastewater treatment plant. The wastewater itself was found to be very toxic to Anabaena CPB4337 (84% of bioluminescence inhibition) whereas it did not have any negative effect on D. magna or V. fischeri. On the contrary, V. fischeri luminescence exhibited a stimulatory effect in wastewater. Discussion Except for fenofibric acid, the Anabaena bioassay was more sensitive than the D. magna and V. fischeri bioassays to bezafibrate, clofibric acid, and gemfibrozil. For the three toxicity tests, fortification resulted in lower measured toxicity for the four compounds, probably indicating a reduced bioavailability due to the interaction with other chemicals in the wastewater or with particulate matter. The observed decrease in toxicity associated to the use of a wastewater matrix was higher for the more hydrophobic compounds reaching one order of magnitude for bezafibrate and gemfibrozil. Conclusions The Anabaena CPB4337 bioassay revealed a certain risk associated with the three less toxic compounds tested. Based on V. fischeri and D. magna bioassays, bezafibrate and gemfibrozil would have been considered non-toxic and harmful, respectively. The use of EC50 data measured in wastewater increases the risk estimation. Recommendations and perspectives Cyanobacteria, as primary producers with a key role in the carbon and nitrogen cycles, are a substantial component of the microbial food webs. Any detrimental effect on this group may have a negative impact in nutrient availability to organisms of higher trophic levels and should be considered in ecotoxicity assessment tests.

... A. Rodríguez*, R. Rosal*, JA Perdigón-Melón*, Alice Petre*, MJ Gomez**, E. García-Calvo* and AR Fernandez-Alba ... Abstract The system ozone and hydrogen peroxide was used to reclaim wastewater from the secondary clarifier from a Sewage Treatment Plant (STP) of Alcalá ...

... catalyst with a platinum content of 0.20 wt.% was also prepared by incipient wetness impregnation ... equation assuming a non-intersecting cylindrical pore model was used to calculate the pore ... over supported Pt catalysts was carried out at a gas hourly space velocity (GHSV) of ...

Monolithic catalysts based on Rh/TiO2–sepiolite were developed and tested in the decomposition of N2O traces. Several effects such as the presence of NO, O2 and NO+O2 in the gas mixture, the catalysts pre-treatment and the metal loading were evaluated. The system was extremely sensitive to the amount of rhodium, passing through a maximum in the catalytic activity at a Rh

... Chem. B, 103 (1999) 1542. 7. Yu.N. Pushkar, A. Sinitsky, OO Parenago, AN Kharlanov and EV Lunina, Appl. Surf. Sci., 167 (2000) 69. RC Mehrotra, R. Bohra and DP Gaur, "Metal -Diketonates and Allied Derivatives" Academic Press, London 1978. . S. Kawagushi, Inorg. Chem. ...

The isothermal and non-isothermal degradation of a typical styrenated phthalic acid-maleic acid-propylene glycol polyester were measured. Non-isothermal and isothermal kinetic analyses were performed on the various degradation steps observed. The values of the non-isothermal and the isothermal kinetic parameters are in good agreement.

The thermal degradation of a sort of polyvinyl chloride was investigated. Complex processes for polyvinyl chloride degradation were evidenced. The kinetic analysis of dehydrochlorination and of subsequent processes was carried out. A change of mechanism was detected when dehydrochlorination goes to completion. The values of non-isothermal kinetic parameters determined by various methods are in a satisfactory agreement. The obtained results allowed some clarifications concerning the thermal degradation steps.

Changes in AC electrical conductance G of vanadium substituted 12-molybdophosphoric acid and of its (mono)-acid and neutral cesium salts were studied. Depending on the environment, the electrical conductivity is a combination of protonic and electronic conduction, the protonic one dominating at low temperature.