STUDIES DEMONSTRATE ENVIRONMENTAL SAFETY  OF LAS IN SEPTIC TANK SYSTEMS

(Washington, DC) – Linear Alkylbenzene Sulfonate (LAS) is effectively removed via biodegradation in septic systems – even under “worst-case” scenarios – according to studies published in the December 2002 issue of Environmental Toxicology and Chemistry (Vol. 21, No. 12).¹

Previous studies have demonstrated that LAS, the most common cleaning agent in household laundry detergents, is effectively biodegraded in municipal wastewater treatment systems. The new studies presented in ET&C show that LAS is rapidly biodegraded in septic systems, which are used by more than 25 million households in the United States.

According to the published research, field studies demonstrated that LAS is biodegraded even under the “worst-case scenario,” or when a septic system’s drainage field is in groundwater during part of the year. A laboratory study confirmed the conclusions of the field tests and showed that soils receiving the septic tank discharge are able to readily biodegrade LAS.

The research was sponsored by the US-based Soap and Detergents Association (SDA) in order to validate an SDA-developed screening model for assessing the fate and transport of common household chemicals in septic systems.   In addition to LAS, the other surfactants studied included alcohol ethoxylate (AE) and alcohol ether sulfate (AES).    The research was directed by the SDA Fate and Effects Subcommittee.    Allen M. Nielsen of Sasol North America Inc., was the chairman of the subcommittee’s Septic Tank Task Force, which led this project. Sasol North America Inc., is a member of the Council for LAB/LAS Environmental Research (CLER).

Abstracts of the three studies can be found on the ET&C web site at http://etc.allenpress.com.

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1 McAvoy, D.C., Decarvalho, A.J., Nielsen, A.M. and Cano, M.L., “Investigation of an Onsite Wastewater Treatment System In Sandy Soil: Modeling the Fate of Surfactants.” Environmental Toxicology & Chemistry, Vol. 21, pp. 2623-2630.

Doi, J., Marks, K.H., DeCarvalho, A.J., McAvoy, D.C., Nielsen, A.M., Kravetz, L., and Cano, M.L. “Investigation of an Onsite Wastewater Treatment System In Sandy Soil: Sorption and Biodegradation Of Linear Alkylbenzene Sulfonate.” Environmental Toxicology & Chemistry, Vol. 21, pp. 2617-2622.

Nielsen, A.M., DeCarvalho, A.J., Kravetz., L., Cano, M.L., and Anderson, D.L. “Investigation of an Onsite Wastewater Treatment System In Sandy Soil: Site Characterization and Fate of Anionic And Nonionic Surfactants.” Environmental Toxicology & Chemistry, Vol. 21, pp. 2606-2616.