May 1996

U.S. RISK ASSESSMENT CONFIRMS ENVIRONMENTAL ACCEPTABILITY OF LAS

A thorough environmental risk assessment of LAS was recently completed by the Soap and Detergent Association of the United States (SDA) and published as a monograph titled “Linear Alkylbenzene Sulfonate.” The assessment concludes:

“The environmental risk assessment for LAS is based on an extensive data base, probably more so than for any other chemical, and the risk assessment substantiates the environmental acceptability of LAS use in U.S. detergents and household cleaning products. The comprehensiveness of the studies carried ou on LAS provides documentation of the environmental safety of LAS that is rarely available for chemicals in commerce.”

Among specific findings of the risk assessment were these:

• LAS readily undergoes primary and ultimate biodegradation under a wide variety of wastewater treatment processes. 
• Traces of LAS ans LAS biodegradation intermediates in effluents from municipal wastewater treatment facilities continue to biodegrade in receiving water environments. 
• Recent monitoring studies from the Mississippi River and from 50 sites in the U.S. confirm that LAS is not accumulating in river waters or sediments. 
• LAS is not impacting sediment organisms in the Mississippi River despite the large wastewater input and the lack of secondary treatment by several large metropolitan cities along the river. 
• LAS applied to soils via sewage sludge biodegrades quickly, with halflives of between 7 and 22 days. No potential for groundwater contamination was indicated. 
• LAS concentrations in sediments below activated sludge treatment facilities are 10 to 100 times lower than NOEC’s (no observable effect concentrations).