Anaerobic Degradation Pathway of Linear Alkylbenzene Sulfonates (LAS) in Sulfate-Reducing Marine Sediments

• Published in: Environmental science & technology Vol. 44; no. 5; pp. 1670 - 1676
• Main Authors: Lara-Martín, Pablo A, Gómez-Parra, Abelardo, Sanz, José Luis, González-Mazo, Eduardo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.03.2010
• Subjects: Alkanesulfonic Acids - chemistry; Anaerobiosis; Applied sciences; Biological and physicochemical properties of pollutants. Interaction in the soil; Chromatography, High Pressure Liquid; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental impact; Environmental Processes; Environmental science; Exact sciences and technology; Geologic Sediments - chemistry; Isomerism; Mass Spectrometry; Oxidation; Oxidation-Reduction; Pollution; Pollution, environment geology; Sediments; Soil and sediments pollution; Solvents; Spain; Sulfates - chemistry; Surfactants; Water - chemistry; Spain; Biodegradation; Sulfate-reducing bacteria; Marine sediments; Pollutant behavior; Metabolite; HPLC chromatography; Metabolic pathway; Time of flight mass spectroscopy; Anionic surfactant; ABS; Ion trap; Anaerobe; Selfpurification; Biotransformation; Degradation product; Mass spectrometry; Organic compounds; Successive reaction
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9032887

Linear alkylbenzene sulfonates (LAS) are among the principal synthetic surfactants used worldwide. Their presence in the environment has been reported in a significant number of studies, and it has been generally assumed that LAS are not biotransformed in the absence of oxygen. However, laboratory experiments performed by our group using anoxic marine sediments have reported LAS degradation percentages that can reach up to 79% in 165 days. Here, we show for the first time the initial reaction metabolites (generated via fumarate addition to the LAS molecules), their biotransformation into sulfophenyl carboxylic acids (SPC), and the progressive degradation of these by successive β-oxidation reactions. Advanced mass spectrometry has been used to carry out the identification of these compounds. This is the first time that an anaerobic degradation pathway for LAS is described, and these results represent a significant advance in understanding the final fate of these and other similar compounds in anoxic environments.