Environmental Safety of the Use of Major Surfactant Classes in North America

Abstract

This paper brings together over 250 published and unpublished studies on the environmental properties, fate, and toxicity of the four major, high-volume surfactant classes and relevant feedstocks. The surfactants and feedstocks covered include alcohol sulfate or alcohol sulfate (AS), alcohol ethoxysulfate (AES), linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), and long-chain alcohol (LCOH). These chemicals are used in a wide range of personal care and cleaning products. To date, this is the most comprehensive report on these substance's chemical structures, use, and volume information, physical/chemical properties, environmental fate properties such as biodegradation and sorption, monitoring studies through sewers, wastewater treatment plants and eventual release to the environment, aquatic and sediment toxicity, and bioaccumulation information. These data are used to illustrate the process for conducting both prospective and retrospective risk assessments for large-volume chemicals and categories of chemicals with wide dispersive use. Prospective risk assessments of AS, AES, AE, LAS, and LCOH demonstrate that these substances, although used in very high volume and widely released to the aquatic environment, have no adverse impact on the aquatic or sediment environments at current levels of use. The retrospective risk assessments of these same substances have clearly demonstrated that the conclusions of the prospective risk assessments are valid and confirm that these substances do not pose a risk to the aquatic or sediment environments. This paper also highlights the many years of research that the surfactant and cleaning products industry has supported, as part of their environmental sustainability commitment, to improve environmental tools, approaches, and develop innovative methods appropriate to address environmental properties of personal care and cleaning product chemicals, many of which have become approved international standard methods.

Keywords: ecotoxicity; environmental exposure; risk assessment.

FIGURE 1.

Production scheme for major surfactants.

FIGURE 2.

Annual consumption in North America of the different classes of surfactants.

FIGURE 3.

Environmental fate of surfactants from consumer products in the United States.

FIGURE 4.

SSD based on chronic NOEC normalized to C_13.5E₃S and resulting HC₅. The data used to develop this distribution are given in Table 26. The mesocosm NOEC for C_12–15E₃S based on Lizotte et al. (2002) normalized to C_13.5E₃S is also shown for comparison.

FIGURE 5.

SSD for the full C_11.6 LAS data set (n = 19 taxa). The blue lines represent the 95% upper and lower confidence intervals of the regression. The predicted HC₅ of 0.19 mg/L is slightly less than the most sensitive species tested, rainbow trout, at 0.23 mg/L.

FIGURE 6.

Suggested approach to assessment of ecologic risk of mixtures of chemicals in the aquatic environment.