February 2001


Evidence that LAS undergoes biodegradation even in the absence of air, i.e. under anaerobic conditions, is the subject of several studies published in the latest issue of The CLER Review (Vol. 6, No. 1), the journal of the Council for LAB/LAS Environmental Research (CLER).

The studies were presented at the CESIO 5th World Surfactants Congress held in Florence, Italy, as well as papers on the fate of LAS in sewage sludge and the fate of surfactants in sediments that also appear in the journal.

Anaerobic biodegradation is the latest key finding to demonstrating the environmental safety of LAS. Dr. John Heinze, technical director of CLER and editor of The CLER Review noted that this new evidence was of special importance to the global detergents industry and should enable detergent products containing LAS to receive the White Swan ecolabel. “Further, it should lead to major revisions in the anaerobic biodegradation criteria used by the White Swan and other environmental labeling programs.” Currently, anaerobic biodegradation is used as a pass/fail criterion for the White Swan ecolabeling program in Scandinavia.

Key studies published in the sixth volume of The CLER Review include:

  • University of Alicante (Spain) study reporting anaerobic biodegradation of LAS using modifications of the ECETOC-28 test;
  • Autonomous University of Madrid study concluding that LAS biodegrades anaerobically even in high concentrations;
  • Denmark Technical University paper reporting anaerobic biodegradation of LAS in laboratory biosolids systems;
  • Cadiz University (Spain) paper finding LAS biodegradation intermediates in anoxic marine coastal sediments;
  • Report demonstrating high removal efficiencies of LAS even in the less efficient “trickling filter” plants and rapid rates of biodegradation in receiving waters;
  • Study documenting low, harmless levels of LAS in the Lambro River (Italy) due to rapid biodegradation of LAS in river water; and
  • Paper showing very rapid removal of LAS in U.S. streams receiving poorly treated sewage from a trickling filter plant.

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