0 AcodEtmie des sciences / Elsevier, Paris GCosciences de surface / Surface Geosciences Reduction in situ des ions nitrate dans des eaux par les bactkies indigenes In situ biological denitrijkation of groundwater Abdesselam Abdelouasa*, Crovisier’ Lijun Deng”, Eric Nuttallb, Werner Lutzeb, Bertrand Fritz”, Jean-Louis a Advanced Materials Laboratory, Center for Radioactive Waste Management, 1001 University Blvd., SE-Suite 201, Albuquerque, NM 87106, USA ’ University of New Mexico, Department of Chemical and Nuclear Engineering, Albuquerque, NM 87131, USA ’ icole et Observatoire des sciences de la Terre, Centre de gkochimie de la surface, CNRS, UMR 7517, 1, rue Blessig, 67084 Strasbourg cedex, France (ReCu le 13 octobre 1998, accept6 apt& kvision le 21 dkembre 1998) Abstract-We studied the possibility of cleaning groundwater contaminated with nitrate ions using indigenous bacteria. The groundwater occurs in a site located near a former vegetable farm near Albuquerque, New Mexico (USA) and contains up to 500 mg.L-’ of nitrate ion. Batch and column experiments using groundwater and local sediment showed that indigenous bacteria catalyzed the nitrate ions reduction. Sodium acetate was selected as the best carbon source for the in situ application. As expected, the best conditions for denitrification were encountered in situ. Nitrate ions and their byproducts were reduced to nitrogen gas within 5 days. hdigenous bacteria / reduction / nitrate ions / groundwater / in situ test R6sumk - Nous avons &udie la possibilite de dkontamination in situ par les bactkies indig&nes d’eaux souterraines contenant des ions nitrate. Les eaux proviennent d’un site localise prb d’une ancienne ferme 2 legumes p&s d’Albuquerque, New Mexico (USA) et contiennent jusqu’a 500 mg.L-’ en ion nitrate. Des expkriences en milieu fermk et en colonnes utilisant les eaux souterraines et le skdiment local ont montre que les batteries indigPnes ont catalysk la rbduction compkte des ions nitrate. L’acktate de sodium a&t& choisi comme source de carbone souhaitable pour I’application in situ. Comme p&vu, les meilleu- res conditions pour la reduction des ions nitrate ont &e observees in situ. La reduction des ions nitrate, ainsi que de leurs produits intermediaires, a &e compkte apres 5 jours. bactkries indigenes / rkduction / ions nitrate / eaux souterraines /test in situ Abridged version Introduction Nitrate contamination of groundwater resources is becom- ing a problem worldwide. Nitrate ion contamination of ground- water is usually caused by over-fertilization, improper disposal of animal and human waste, and industrial waste streams. In the United States nitrate ion concentrations above 44 mg,L-’ are considered harmful and can be fatal to infants under six months of age (Kapoor and Viraraghavan, 1997). The “blue baby syndrome” or “methemoglobinemia” has affected 2 000 infants worldwide since 1945; 8 % of these cases resulted in death (Bitton and Gerba, 1984). Other health effects of high level of nitrate ions in drinking water include cancer in adults (Mirvish, 1991) and birth defects (Dorsch et al., 1984). Note prbentbe par Jean Dercourt. * Correspondance et tin% a part badria@unm.edu C. R. Acad. Sci. Paris. Sciences de la terre et des plan&es / Earth & PlanetarySciences 1999.328.161-166 161