ALICE PETRE

The continuous ozonation of the antibiotic ofloxacin (OFX) has been performed using a synthetic water matrix and in a sewage treatment plant (STP) effluent. The aim was to study the effect of the water matrix on the ozonation with particular emphasis on the aquatic toxicity of treated water. OFX was completely removed in both water matrices, although the amount of ozone consumed for its depletion was strongly matrix-dependent. The extent of mineralization was limited and a number of intermediate transformation products (TPs) appeared, twelve of which could be identified. OFX reaction pathway includes the degradation of piperazinyl and quinolone moieties. The further oxidation of TPs gave rise to the formation and accumulation of carboxylic acids, aldehydes, nitrogen-containing organic compounds and inorganic ions. Aquatic toxicity of treated mixtures was assessed using four standard species: the bacteria Vibrio fischeri and Pseudomonas putida as target organisms and the algae Pseudokirchneriella subcapitata and the protozoan Tetrahymena thermophila as non-target organisms. OFX was toxic for the bacteria and the microalgae at the spiked concentration in untreated water. However, the continuous ozonation at the upper operational limit removed its toxic effects. T. thermophila was not affected by OFX, but was sensitive to STP effluent.

The contact assay measuring the inhibition of Arthrobacter globiformis dehydrogenase activity as an endpoint to evaluate the toxicity of solid samples was tested in an international ring-test to validate its performance for ISO standardization (ISO/CD 18187). This work reports the results of the ring-test involving 9 laboratories from six countries. At least 8 valid data sets were obtained for each sample and more than three quarters of the participants attained the validity criteria defined in the standard. The coefficient of variation within (CV) and between (CV) laboratories was generally on average <15% and <30% for negative and positive controls, respectively. Regarding solid samples, the laboratories provided a similar ranking of the samples based on their toxicity, despite some variation in the LOEC values. The logarithmic within-lab standard deviation <0.50 for soils and <0.25 for wastes evidenced a good repeatability. The between-lab variability assessed by a CV...

Long chain alkylaromatics, such as n-dodecylbenzene, are important starting points for the production of surfactants and form the basis for the production of many biodegradeable detergents. It this presentation we use n-dodecylbenzene disproportionation as a probe for acid activity and selectivity in ionic liquid catalyzed dealkylation and disporportionation of long chain alkylaromatics. The ionic liquid catalysts used in this study comprise ionic liquid – functionalized high surface area silica materials including MCM-41. The study showed that AlCl3-based ionic liquids supported on silicas and MCM-41 are active catalytic materials for alkylbenzene (DDB) transformation (mainly disproportionation and dealkylation) at low reaction temperatures. We also concluded that the catalytic dealkylation of n-dodecylbenzene requires a high density of very strong acid sites.

The surface properties of supported gallium oxide catalysts prepared by impregnation of various supports (γ-Al2O3, SiO2, TiO2, ZrO2) were investigated by adsorption microcalorimetry, using ammonia and water as probe molecules. In the case of acidic supports (γ-Al2O3, ZrO2, TiO2), the acidic character of supported gallium catalysts always decreased in comparison with gallium-free supports; on very weakly acidic SiO2, new acidic

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.

... 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. ...

... 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 ...

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.

... 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. ...

... 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 ...

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.

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

... 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 ...