Contribution of ecotoxicological tests in the evaluation of soil bioremediation efficiency

Clean-up of contaminated soils became a high priority only recently. Several techniques have been developed forthis purpose such as chemical, physical, thermic or microbiological methods. Efficiency of the remediation can be estimated using two approaches : a chemical specific approach and a toxicity-based approach. So far, the efficiency of the decontamination process was based essentially on chemical analyses which does not integrale the toxicity of all the soil contaminants and does not give a response on effects caused by the bioavailable fraction of these contaminants äs the toxicity-based approach. In the present study, bioremediation efficiency of a soil contaminated by 4-chlorobiphenyl was evaluated using chemical and biological analyses. Experiments were carried out in microcosms contaminated at a rate of 1 g/kg. Control microcosms without specific degrader were performed simultaneously. Acute toxicity to earthworms and inhibition of growth of barley roots were selected, from previous work, äs relevant ecotoxicological test

The look of the con: Eleven thoughts on the historical absence of subtitles in film analysis

This article considers the lack of dialogue between Audio-Visual Translation and Film & Media Studies, despite the fact that both disciplines clearly have shared interests in the content of audio-visual texts. The apparent lack of any developed and consistent overlap between these areas of study is the starting point for a series of eleven ‘thoughts' that identify commonalities and differences in how film and television texts might be studied and analysed. Inspired and led by the specific example of a scene from Ocean’s Eleven (2001), the article explores the potential for interdisciplinary research collaborations through ideas of authorship, genre, history, technology, industry labour, and reception and audience studies. While identifying areas where different theories might clash or complicate collaboration, the article also highlights potent areas where shared experience and different perspectives could enrich both fields

Evaluation of a bioremediation process efficiency : contribution of analytical, microbiological, molecular and ecotoxicological methods

International audienceIn order to set the parameters of the experiments, the study was first carried out in artificial soil microcosms contaminated with 4-chlorobiphenyl. A biphenyl degrader, Pseudomonas sp. B4, was introduced into the microcosm and its presence was checked by microbiological and molecular methods

The use of quantitative PCR, plant and earthworm bioassays, plating and chemical analysis to monitor 4-chlorobiphenyl biodegradation in soil microcosms

International audience4-Chlorobiphenyl biodegradation was monitored using several methods including molecular detection, microbiological and ecotoxicological techniques and analytical tools. Experiments were carried out in microcosms with artificial soil and an uncultivated sandy loam soil, contaminated at a rate of 1 g kg(-1) of 4-chlorobiphenyl. Two strains were used for bioremediation: a 4-chlorobiphenyl degrader, the bacterial strain Pseudomonas sp, strain B4 and the bacterial strain Pseudomonas sp, strain CBS3 which is able to mineralize 4-chlorobenzoate. Molecular tools were constructed for the detection and the quantification of dihydroxybiphenyl dioxygenase gene (bphC) from Pseudomonas sp. strain B4 and for the detection of the 4-chlorobenzoate coenzyme A dehalogenase gene from Pseudomonas sp. strain CBS3. Evidence was found for 4-chlorobiphenyl toxicity to barley and earthworms using standardized ecotoxicological tests. When Pseudomonas sp. strain B4 was introduced alone into microcosms, no decrease in toxicity occurred although 4-chlorobiphenyl was entirely degraded. The introduction of Pseudomonas sp. strain CBS3 into inoculated microcosms resulted in the disappearance of the 4-chlorobenzoate accumulated during the degradation of 4-chlorobiphenyl by Pseudomonas sp. strain B4, and in the disappearance of any toxic effect indicating that remediation was complete. Similar results were obtained independent of the nature of the soil used in microcosms. These results underline the need for taking biological effects into account in order to assess remediation efficiency