Monitoring the Primary Biodegradation of Linear Alkylbenzene Sulfonates and Their Coproducts in Anoxic Sediments Using Liquid Chromatography-Mass Spectrometry

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• 作者：Pablo A. Lara-Martí ; n ; Abelardo Gó ; mez-Parra ; Thorsten Kö ; chling ; José ; Luis Sanz ; Eduardo Gonz&aacute ; lez-Mazo
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：May 15, 2007
• 年：2007
• 卷：41
• 期：10
• 页码：3580 - 3586
• 全文大小：445K
• 年卷期：v.41,no.10(May 15, 2007)
• ISSN：1520-5851

文摘

An accompanying article has demonstrated the anaerobicdegradation of the surfactant linear alkylbenzene sulfonate(LAS) in microcosms filled with marine sediments throughthe generation of sulfophenylcarboxylic acids (SPCs). Adetailed study shows that this process was uniform in theblanks (non-spiked natural sediments) for every LAShomologue during the complete course of the experiment.However, when sediments were spiked with commercialLAS and, therefore, enriched with short-chain homologues,degradation was enhanced for these homologues untiltheir percentages were close to those for non-spikedsediments. The reason is that short-chain homologues aremore bioavailable due to their higher solubility andlower sorption capacity. Thus, sorption on sediments wasfound to be increased with the length of the alkyl chainfor LAS homologues, following a linear Freundlich isotherm,whereas the metabolites generated were predominant insolution due to their much higher polarity. Intermediate-chainSPC homologues (C₇-C₉ SPCs) were the most abundantduring the experiment, but a significant increase inthe concentration of shorter-chain SPC homologues(C₄-C₆ SPCs) was detected toward the end. In the caseof isomers, the steric effect of the aromatic group impliesthat LAS primary degradation took place preferentiallyover external isomers. Therefore, the generation of externalisomers of SPCs was predominant during the completeexperiment although internal isomers of SPCs became moreevident when the degradation process had advancedand external isomers of LAS became scarce. The identityof both types of SPC isomer was confirmed by tandemmass spectrometry. With respect to LAS coproducts, therelative percentage of iso-LAS increased during the completeexperiment and removal percentages for dialkyl tetralinsulfonates (<30%) were typically lower that those for LAS (66-79%), although a similar behavior was observed for theirhomologues in both cases.