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Soil microbial community response to a selenium chronic exposure



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Titre du congrès :SETAC Europe 17th Annual Meeting Ville du congrès :Porto Date du congrès :20/05/2007

Type de document > *Congrès/colloque

Mots clés > communauté bactérienne, sélénium, sol, volatilisation

Unité de recherche > IRSN/DEI/SECRE/LRE

Auteurs > COLINON Céline, COURNOYER Benoit, FEVRIER Laureline, NAZARET Sylvie, RANJARD Lionel

Date de publication > 24/05/2007


Selenium is an essential trace element for living organisms and is known to become rapidly toxic within a narrow range. Some microorganisms can reduce Se toxicity by reducing the oxidized forms of selenium into insoluble elemental Se or by volatilizing them into methylated selenides. The aim of this study was to investigate the response of soil microbial communities during the incubation of artificially contaminated soils with selenite (SeO32-). Two contrasted soils were studied (a sand and a silty-clay soil) and three contamination levels (Se = 0, 0.008, 8 ppm) were compared. Contaminated soils were incubated for six months under constant temperature and humidity. An organic amendment was supplied after three months of incubation. Responses of the soil microbial communities were screened through respiration rate, bacterial counts, community level physiological profiles (Biolog Ecoplates) and bacterial communities structure (B-RISA). Fluxes of volatile Se were also monitored. The relative sensitivity of these different microbial endpoints for Se contaminated soils risk assessment will be discussed.