title: Effect of a sulfonated azo dye and sulfanilic acid on nitrogen transformation processes in soil.
abstract: Introduction of organic dyes into soil via wastewater and sludge applications has been of increasing concern especially in developing or under-developed countries where appropriate management strategies are scarce. Assessing the response of terrestrial ecosystems to organic dyes and estimating the inhibition concentrations will probably contribute to soil remediation studies in regions affected by the same problem. Hence, an incubation study was conducted in order to investigate the impact of a sulfonated azo dye, Reactive Black 5 (RB5) and sulfanilic acid (SA), a typical representative of aromatic sulfonated amines, on soil nitrogen transformation processes. The results apparently showed that nitrogen related processes in soil can be used as bioindicators of anthropogenic stress caused by organic dyes. It was found that urease activity, arginine ammonification rate, nitrification potential and ammonium oxidising bacteria numbers decreased by 10-20% and 7-28% in the presence of RB5 (> 20 mg/kg dry soil) and SA (> 8 mg/kg dry soil), respectively. Accordingly, it was concluded that organic dye pollution may restrict the nitrogen-use-efficiency of plants, thus further reducing the productivity of terrestrial ecosystems. Furthermore, the response of soil microbiota to SA suggested that inhibition effects of the organic dye may continue after the possible reduction of the parent dye to associated aromatic amines.
authors.affiliation: Uludağ University, Department of Environmental Engineering, Görükle 16059, Bursa, Turkey. olcaytopac@uludag.edu.tr
authors.forename: F Olcay
authors.initials: FO
authors.lastname: Topaç
authors.forename: Efsun
authors.initials: E
authors.lastname: Dindar
authors.forename: Selnur
authors.initials: S
authors.lastname: Uçaroğlu
authors.forename: Hüseyin S
authors.initials: HS
authors.lastname: Başkaya
mesh_terms: D000332:Aerobiosis; D000704:Analysis of Variance; D001120:Arginine / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008903:Minerals / Q000737:chemistry; D009282:Naphthalenesulfonates / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry*; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D013425:Sulfanilic Acids / Q000737:chemistry*; D014510:Urease / Q000737:chemistry
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D008903:Minerals; D009282:Naphthalenesulfonates; D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012987:Soil; D013425:Sulfanilic Acids; D001120:Arginine; D014510:Urease; D009584:Nitrogen; C063421:Remazol black B