| Abstract
| - The 2 800-km reach of the Mississippi River betweenMinneapolis, MN, and New Orleans, LA, wasexamined for the occurrence and fate of linearalkylbenzene sulfonate (LAS), a common anionic surfactant found in municipal sewage effluents. Riverwater and bottom sediment were sampled in the summerand fall of 1991 and in the spring of 1992. LAS wasanalyzed using solid-phase extraction/derivatization/gas chromatography/mass spectrometry. LAS waspresent on all bottom sediments at concentrationsranging from 0.01 to 20 mg/kg and was identifiedin 21% of the water samples at concentrations rangingfrom 0.1 to 28.2 μg/L. The results indicate thatLASis a ubiquitous contaminant on Mississippi Riverbottom sediments and that dissolved LAS is presentmainly downstream from the sewage outfalls ofmajor cities. The removal of the higher LAS homologsand external isomers indicates that sorption andbiodegradation are the principal processes affectingdissolved LAS. Sorbed LAS appears to degradeslowly.
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