Vol. 14, No.1 (May 2015) – Preface
A Tale of Two Studies
This Editor’s Preface points out what is notable about the studies in the current issue of The CLER Review and provides an overview of the papers and why they are of interest. The studies in this issue focus on linear alkylbenzene sulfonate (LAS), a major cleaning agent (surfactant) used in laundry detergents and cleaning products now and for the past 40 years. While most papers in The CLER Review typically focus on LAS, this issue is notable for at least three reasons.
First, this issue contains only two articles—the first volume of The CLER Review to do so. Previous issues have either featured a single article or have contained four or more studies.
Second, the first study in this issue is a very comprehensive review—one of the longest articles to appear in this publication’s pages—while the other is one of the shortest, most focused research studies we have published.
Finally and most importantly, these studies have been chosen for publication for the quality of their content.
The first (and longer) paper is an edited version of the paper by C. Cowan-Ellsberry (CE Consulting, Cincinnati, Ohio, USA) and colleagues , which comprehensively reviewed the environmental safety of the four major surfactants classes used in North America (alcohol ethoxylates, alcohol ethoxysulfates, alcohol sulfates, and LAS), as well as the major feedstock (long-chain alcohols) used to make the first three surfactants groups. The paper that appears in The CLER Review has been edited with the permission of the authors and the publisher to focus exclusively on the LAS data.
The LAS data is quite comprehensive and includes both published and unpublished studies on environmental properties (chemical structure, use, production volume, and relevant physical/chemical properties); fate (biodegradation, bioaccumulation, absorption to soil, and sediment); and toxicity (to both aquatic and terrestrial organisms). The review includes a “prospective” risk assessment, one using modeling to compare predicted levels of LAS in the environment to levels that would pose a risk to aquatic or sediment environments. This risk assessment demonstrates that LAS, in the words from the review, “although used in very high volume and widely released to the aquatic environment (due to its use in laundry detergents), has no adverse impact on the aquatic or sediment environments at current levels of use.”
The review also considers data available from a “retrospective” risk assessment—one using measured levels of the LAS actually in the environment. The review concludes that the retrospective risk assessment “has clearly demonstrated that that the conclusion of the prospective risk assessment is valid and confirms that LAS does not pose a risk to the aquatic or sediment environments.”
One could hardly wish for a stronger endorsement of the environmental safety of LAS. It should be noted that the original paper by Cowan-Ellsberry and colleagues2 reaches the same affirmative conclusion in its review of alcohol ethoxylates, alcohol ethoxysulfates, alcohol sulfates, and long-chain alcohols: namely, that these substances do not pose a risk to aquatic or sediment environments.
The review concludes by pointing out that, as part of their environmental sustainability commitment, the surfactants and cleaning products industry supports—and has supported for many years—research to develop and improve methods used to study cleaning product chemicals. CLER is pleased to have supported research in this area as well. See, for instance, M.L. Trehy and colleagues, which reports the development and use of new analytical methods for detecting environmental levels of LAS biodegradation intermediates.
The second (shorter) study is by F. Renaud (Environment Laboratories, International Atomic Energy Agency, Monaco) and colleagues. An important question for any viable risk assessment is to determine if the substance bioaccumulates in aquatic organisms. This is because even if the substance is present at low concentrations in the environment, it may still cause harm if it accumulates in tissues to harmful concentrations (bioaccumulates). For LAS, previous studies have determined low potential to bioaccumulate in freshwater fish.
Renaud and colleagues, noting that LAS is detected in coastal waters receiving untreated wastewater, conducted a study of LAS bioaccumulation in a marine organism, the shrimp Palaemonetes varians. The results showed LAS has low potential for bioaccumulation in marine shrimp. The study further determined that following cessation of exposure, LAS is rapidly removed from the shrimp via natural metabolic processes so that after just eight days, less than 1% remains. This test provides valuable supplemental data for risk assessments, such as the European Union REACH program.
Jointly, these two studies affirm research previously highlighted in The CLER Review while contributing valuable new data on the safety and sustainability of LAS use.
John Heinze, Ph.D.
1. Vol. 9: Human and Environmental Risk Assessment (HERA) of LAS; vol. 10: OECD SIDS Initial Assessment Report of LAS.
2. Critical Reviews in Environmental Science and Technology, 44:1893-1993, 2014.
3. The CLER Review, 3:32-43, 1997.
4. Marine Pollution Bulletin, 85:244-247, 2014.