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Susceptibility of synthetic long-chain alkylbenzenes to degradation in reducing marine sediments

Environmental Science and Technology

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DOI: 10.1021/es801132y

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Abstract

Long-chain alkylbenzenes (LCABs) synthesized for production of alkylbenzene sulfonate surfactants have been used as molecular markers of anthropogenic waste for 25 years. Synthetic LCABs comprise two classes, the tetrapropylene-based alkylbenzenes (TABs) and the linear alkylbenzenes (LABs). LABs supplanted TABs in the mid-1960s because of improved biodegradability of their sulfonated analogs. Use of LCABs for molecular stratigraphy depends on their preservation in sediments over decadal time scales. Most laboratory and field studies suggest that LABs degrade rapidly under aerobic conditions but are resistant to degradation when oxygen is absent. However, recent work indicates that LABs may not be as persistent under reducing conditions as previously thought. To assess the potential for degradation of LCABs in reducing sediments, box cores collected in 1992 and 2003 near a submarine wastewater outfall system were analyzed using gas chromatography/mass spectrometry. The TABs were effectively preserved; differences between whole-core inventories were within analytical error. By contrast, whole-core inventories of the LABs decreased by about 50-60% during the same time interval. Based on direct comparison of chemical inventories in coeval core sections, LAB transformation rates are estimated at 0.07 ±. 0.01 yr-1. These results indicate that caution should be exercised when using synthetic LCABs for reconstruction of depositional records.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Susceptibility of synthetic long-chain alkylbenzenes to degradation in reducing marine sediments
Series title:
Environmental Science and Technology
DOI:
10.1021/es801132y
Volume
42
Issue:
17
Year Published:
2008
Language:
English
Publisher:
ACS Publications
Publisher location:
American Chemical Society
Contributing office(s):
Branch of Regional Research-Eastern Region
Description:
8 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Science and Technology
First page:
6361
Last page:
6368