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Recent decisions by regulatory organizations and governmental bodies confirm that LAS is environmentally safe and completely acceptable for use in laundry detergents and cleaning products.

European Detergent Ecolabel

• The European Union (EU), under Council Regulation (EEC) 880/92, is developing criteria for ecolabel awards for various product groups. The criteria will apply across the EU to provide consumers with guidance on products with reduced environmental impact.(1)
• The ecolabel criteria for laundry detergents were approved by the EU ecolabel Representative Committee and recently published.(2)
• The adequacy of the environmental information on LAS is recognized by its inclusion in the Detergent Ingredient Database list.
• Laundry detergents based on LAS will be able to meet all ecolabel criteria and will be eligible to receive the ecolabel award.

Dutch Environmental Safety Assessment

• The Dutch Environmental Ministry (VROM), in cooperation with the Dutch Institute of Human Health and Environmental Protection (RIVM) and the Dutch Detergent Association (NVZ), has conducted an extensive review of the environ mental safety of laundry detergent ingredients.
• The first phase of this safety assessment focuses on major detergent actives, including LAS.
• A real world monitoring study, conducted in the Netherlands as part of VROM’s safety assessment, demonstrated that more than 99% of the LAS is removed during sewage treatment. This result confirms the very high removal rates for LAS observed in treatment plants in Europe and the U.S.(3-6)

• Based on the results of the monitoring study, the predicted environmental concentration for LAS in rivers and waterways downstream of Dutch sewage treatment plants is very low, only 4 to 6 parts per billion.
• The extensive environmental safety data on LAS and a conservative statistical extrapolation method were used to predict the highest level that would be safe for aquatic organisms, the “Maximum Permissible Concentration” (MPC).
• LAS was determined to be safe at levels as high as 250 parts per billion (MPC value), much higher than the predicted environmental concentration of 4 to 6 parts per billion. At current usage levels, LAS poses no risk to the Dutch en vironment.
• This rigorous and very conservative risk assessment process confirms the conclusion of earlier assessments that LAS use in laundry detergents and cleaning products is safe for the environment.(3,7-9)
• The complete results of this safety assessment are available in a report released by the National Institute of Public Health and Environmental Protection and the Dutch Soap Association.(10)

OECD Safety Assessment on LAB

• The Organization for Economic Cooperation and Development (OECD) is conducting a safety assessment on large production volume chemicals.
• Linear alkylbenzene (LAB), the material used to produce LAS, was chosen to be among the first group of chemicals to be examined. LAB was included in this group because of the large amount of health and environmental safety informati on available on it.
• LAS is in the second group of chemicals to be examined since more LAB is transported worldwide than LAS.
• The U.S. Environmental Protection Agency, which is responsible for the LAB safety assessment, has compiled the LAB information into a computerized document called the Screening Information Data Set (SIDS) dossier.
• The LAB dossier was reviewed at the February, 1995, OECD meeting. LAB was classified as “category 1”, meaning that no additional testing is needed and that LAB as currently used is safe.

• The LAB dossier has now been finalized based on comments made at the OECD meeting.

UK Department of the Environment Report

• The Technical Committee on Detergents and the Environment was formed by the United Kingdom Department of the Environment to review the effects of detergents and cleaning products on the environment, to identify potential pro blems and to issue reports of their findings. The committee is composed of experts from the British government, academia and industry.
• The latest report, dated December 1994, contains an assessment of the safety of LAS. The assessment is based on an extensive review of the research and published literature on LAS, including the proceedings of several international symposia.(11)
• The review included an examination of the relevance of anaerobic biodegradability for LAS: “LAS levels in river sediments receiving untreated sewage or poorly treated effluent have been reported as ranging up to 500 mg/kg. How ever, oxygen levels have not been simultaneously measured and it seems likely that real-world conditions are more commonly oxygen-limited rather than strictly anaerobic. Such conditions slow the rate but do not prevent LAS mineralization.”
• The report concludes that “LAS is readily biodegradable” and its widespread use in consumer products poses no hazard to human health or the environment. The report further notes that “LAS has remained the major surfactant throughout the world because of its effectiveness, versatility, cost/performance ratio and environmental safety.”

KEY REFERENCES

1. Official Journal of the European Communitie. No. L 99. April 11, 1992.

2. Official Journal of the European Communitiee. No. L217/14. September 13, 1995.

3. McAvoy, D.C., W.S. Eckhoff and R.A. Rapaport. “Fate of Linear Alkylbenzene Sulfonate in the Environment.” Environ. Toxicol. Chem. 12, 977-987 (1993).

4. Cavalli, L., A. Gellera and A. Landone. “LAS Removal and Biodegradation in a Wastewater Treatment Plant.” Environ. Toxicol. Chem. 12, 1777-1788 (1993).

5. Snchez Leal, J., M.T. Garca, R. Toms, J. Ferrer and C. Bengoechea. “Linear Alkylbenzene Sulfonate Removal.” Tenside Surf. Det. 31, 253-256 (1994).

6. Waters, J. and T.C.J. Feijtel. “AIS/CESIO Environmental Surfactant Monitoring Program: Outcome of Five National Pilot Studies on Linear Alkylbenzene Sulfonate (LAS).” Chemosphere 30, 1939-1956 (1995).

7. Kimerle, R.A. “Aquatic and Terrestrial Ecotoxicology of Linear Alkylbenzene Sulfonate.” Tenside Surf. Det. 26, 169-176 (1989).

8. Lewis, M.A. “Chronic and Sublethal Toxicities of Surfactants to Aquatic Animals: A Review and Risk Assessment.” Wat. Res. 25, 101-113 (1991).

9. Rapaport, R.A., R.J. Larson, D.C. McAvoy, A.M. Nielsen and M. Trehy. “The Fate of Commercial LAS in the Environment.” 3rd CESIO International Surfactants Congress & Exhibition — A World Market, Proceedings, Section E, 78-88 ( London, June 1-5, 1992).

10. Feijtel, T.C.J. and E.J. van de Plassche. “Environmental Risk Characterization of 4 Major Surfactants Used in the Netherlands.” National Institute of Public Health and Environmental Protection and Dutch Soap Association (The Neth erlands, September 1995) Report no. 679101 025.

11. Otter, R.J. et al. “Second Report of the Technical Committee on Detergents and the Environment.” Department of the Environment (London, December, 1994) pp. 4-5, 53-60.

Last updated on May 1996

 

The Council for LAB/LAS Environmental Research (CLER) is an organization of scientists and technical specialists representing member companies Huntsman Corporation (Houston), Petresa (Madrid), Sasol North America (Houston), Quimica Venoco (Venezuela) and Repsol YPF (Argentina). CLER’s mission is to evaluate data, conduct research and distribute scientific information on the environmental safety of the world’s number one surfactant, linear alkylbenzene sulfonate (LAS) and the material from which it is produced, linear alkylbenzene (LAB).

For thirty years, LAS has been the major surfactant used in laundry detergents and other cleaning products. Supporting this long history of safe use is an enormous database of environmental research on LAS. This research has looked at virtually every part of the environment that might be exposed to LAS and considered all the components of commercial LAS. Moreover, the research on LAS has revealed important lessons about test methods and environmental acceptability.

Detergent components such as LAS typically go down the drain after use and flow into municipal sewage treatment plants or domestic septic systems. In some cases, more common in less developed parts of the world, disposal is directly into streams, rivers or the oceans.

Many studies have been conducted in the U.S. and in Europe on what happens to LAS during sewage treatment. Biological breakdown (biodegradation) of LAS actually begins in the raw sewage before it reaches the treatment plant. Once LAS re aches the sewage treatment plant, it is rapidly biodegraded and extensively removed. In modern treatment plants, LAS removal often exceeds 99%.

Treated water from sewage treatment plants is returned to streams, rivers or the oceans. LAS concentrations in the water and sediments of streams, rivers and oceans receiving treated water are very low and pose no risk to the organisms present. Any remaining LAS will continue to biodegrade until it is reduced (mineralized) to materials harmless to the environment (carbon dioxide, water and sulfate salts).

During sewage treatment, solids are separated from water, and some LAS adsorbs to the solids. These solids, called sludge, can be incinerated, placed in landfills or used as a soil conditioner or fertilizer. LAS does not harm crops plan ted in soil fertilized with sludge. Residual LAS continues to biodegrade so that yearly applications of sludge to agricultural lands does not cause any build up of LAS.

LAS is also rapidly biodegraded and efficiently removed in septic systems, thereby protecting groundwater resources.

Commercial LAS contains three constituents in addition to LAS itself: linear alkylbenzene (LAB), dialkyltetralin sulfonate (DATS) and methyl-branched alkylbenzene sulfonate (isoLAS). LAB, DATS and isoLAS have been shown to biodegrade ra pidly and completely, and are safe for the organisms present in the environment.

Concerns have been expressed about detergent components and other materials that may become attached (adsorbed) to sediments deposited in oxygen free (anaerobic) environments where biodegradation is thought to proceed at a slower pace, if at all. Recent studies have shown that LAS can biodegrade under oxygen limited (anoxic) conditions, which represent an intermediate environment between oxygen available (aerobic) and anaerobic conditions. Aerobic and anoxic conditions seem to be much m ore common than anaerobic ones. Moreover, LAS levels in the environment are low, or not detectable, and pose no risk to the organisms present. Consequently, anaerobic conditions are not a problem for LAS environmental safety.

Because there is so much real world data on LAS, results from field and monitoring tests on LAS can be used to evaluate how well laboratory test methods predict real world results. This information is important to know since pass/fail r esults in laboratory tests are sometimes used for regulatory or environmental labeling purposes. The real world studies on LAS have shown that reliance on laboratory tests greatly underestimates the environmental safety of LAS.

In addition to the results from studies on biodegradation and environmental safety, the environmental acceptability of detergent components can be evaluated from an examination of the resources and energy consumed and the air, water and solid wastes produced in their manufacture. A systematic compilation of the total resources, energy and wastes involved, called a Life Cycle Inventory, is a massive undertaking that has only been attempted for the major cleaning agents (surfactants). Com parison of the results indicates that no surfactant can claim to be superior for the environment. Contrary to statements made by some suppliers of vegetable (oleochemical) based surfactants, petrochemical based surfactants such as LAS are just as environm entally acceptable as oleochemical based surfactants.

In fact, the environmental safety and acceptability of LAS has been recently confirmed in several major regulatory decisions. This includes environmental labeling decisions on laundry detergents in Europe, a rigorous environmental safet y assessment in The Netherlands, a comprehensive safety assessment on LAB by the Organization for Economic Cooperation and Development (OECD) and a health and environmental safety assessment on LAS by the UK Department of the Environment.

This database on LAS, more extensive than on any other surfactant, provides complete assurance that LAS is environmentally safe and acceptable, and that LAS will be recognized as such for the foreseeable future.

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