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

This paper brings together over 250 published and unpublished studies on the environmental properties, fate, and toxicity of the four major, high-volume surfactant classes and relevant feedstocks.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.

Assessment of the ecological effects of arsenic on a southern Ohio, USA stream.

Davis Creek is a southern Ohio, USA stream that receives a permitted discharge from the Belpre Elastomers Plant (BEP). A sediment quality triad investigation of Davis Creek was conducted over a 2-y period that included sediment and surface water chemistry measurements, toxicity tests of whole sediment, interstitial and surface water, and benthic and artificial substrate community assessments. The concentration of arsenic in surface and interstitial water was below United States Environmental Protection Agency ambient water quality criteria and was not toxic in laboratory tests (Ceriodaphnia dubia, Pimephales promelas). Similarly, sediments did not significantly affect survival and growth of Hyalella azteca and Chironomus tentans at most sampling locations despite sediments exceeding arsenic sediment screening values in nearly all samples collected. Differences in benthic community structure, determined by rapid bioassessment and Hester-Dendy sampling methods, were related primarily by variations in sediment moisture, particle size, and ammonia and not to arsenic concentrations. The Invertebrate Community Index (ICI) for Davis Creek was lower than values established for other warm-water ecoregional reference streams in Ohio. However, this ICI comparison may have been invalid because, unlike the reference streams, the Davis Creek watershed is small with intermittent headwater flow that limits macroinvertebrate recruitment and energy input. The sediment quality triad investigation indicated that Davis Creek was not significantly affected by arsenic associated with the BEP discharge despite having measured arsenic concentrations that exceeded sediment screening values.

A stream mesocosm study on the ecological effects of a C12-15 linear alcohol ethoxylate surfactant.

The responses of fish, invertebrates, and periphyton during a 56-day exposure to a C(12-15) linear alcohol ethoxylate surfactant were studied in stream mesocosms. An individual stream consisted of a slow-flowing pool section and a faster-flowing riffle section. The surfactant has an average distribution of nine ethoxylate groups per mole of alcohol. Eight stream mesocosms were used to test the effects of seven concentrations of the surfactant. Time-averaged, mean, measured concentrations were 20, 40, 70, 160, 300, 390, and 740 microg/L, which represented 70-100% of nominal concentrations. The exposure of aquatic communities to the C(12-15)AE-9 surfactant in stream mesocosms resulted in no-observed-effect concentrations (NOECs) for individual endpoints ranging from 160 to 740 microg/L. Among the more sensitive responses were Oncorhynchus mykiss time to swim up and fry growth, abundance of juvenile Gammarus pulex in drift samples, Baetis abundance in the riffle sediment and in samples collected from tiles placed in the riffle, and Simulium density in the riffle tiles, all with NOECs of 160 microg/L. Responses of the riffle sediment invertebrate assemblages assessed using multivariate methods support a NOEC of 160 microg/L. Abundances of G. pulex, Copepoda, and Agapetus sampled in the pools and pool tiles were not affected at the highest surfactant concentration tested after 56 days. Surfactant effects on periphyton and community leaf processing were seen at 300-390 microg/L. Based upon the responses of several taxa representing different trophic levels, a mesocosm NOEC of 160 microg/L can be stated for the C(12-15)AE-9 surfactant. This study provided additional data that can be used to reduce the uncertainty in extrapolating laboratory data to the field for the environmental risk assessment of alcohol ethoxylates.

Spatial and temporal variability in the structure of invertebrate assemblages in control stream mesocosms.

Outdoor stream mesocosm studies conducted between 1992 and 1996 at two facilities enabled the investigation of structural variability in invertebrate assemblages within and between studies. Temporal variability of benthic invertebrate assemblages between eight replicate streams within a study was assessed in a 28-day mesocosm study without chemical treatment. Cluster analysis, non-metric multidimensional scaling, and principal component analysis each showed the untreated assemblages as structurally distinct groups on the three sampling days. The assemblages between the eight replicate streams showed >88% Bray-Curtis similarity at any one time during the study. In addition, pre-treatment data from a series of four studies conducted at one facility were used to examine structural variability in the starting benthic invertebrate assemblages between studies. Invertebrate assemblages were structurally distinct at the start of each mesocosm study conducted in different years at the same facility and the taxa responsible for differences in the assemblages were also different each year. The implications of temporal and spatial variability in benthic invertebrate assemblages within and between mesocosm studies with regards to species sensitivity and study repeatability should be considered when results of such studies are used in risk assessment.

Ecological effects of an anionic C12-15 AE-3S alkylethoxysulfate surfactant in outdoor stream mesocosms.

The ecological assessment of a C12-15 AE-3S linear alkylethoxysulfate (AES) anionic surfactant to invertebrates, fish, periphyton, and an aquatic macrophyte was conducted in a 30-d outdoor stream mesocosm study with five replicated concentrations and controls. Alkylethoxysulfate structural integrity and exposure concentrations were maintained during the 30-d treatment period, with average measured concentrations of 0.7, 1.27, 2.2, 4.31, and 10.18 mg/L. No effects were observed on the aquatic macrophyte Myriophyllum aquaticum at the highest concentration tested. A sevenfold increase in periphyton biomass at 10.18 mg/L was observed relative to controls primarily because of increases in density of the filamentous alga Mougeotia sp. Densities of the invertebrates Annelida (Stylaria), Amphipoda, Copepoda, Trichoptera (Hydropsychidae), Cladocera, and Diptera (Chironomidae) significantly decreased in streams treated with AES at 10.18 mg/L. Densities of drifting invertebrates were not observed to be affected at any concentration tested. Reproduction of Pimephales promelas significantly decreased at 1.27 mg/L and growth of juvenile Lepomis macrochirus was significantly affected at 4.31 mg/L. Multivariate cluster analysis and nonmetric multidimensional scaling ordination showed distinct structural effects on the invertebrate communities in the streams treated with AES at 10.18 mg/ L compared to the control and streams treated at < 10.18 mg/L through the 30-d treatment. Convergence of the communities treated at 10.18 mg/L toward control communities in the ordination suggests recovery in these communities after termination of surfactant treatment. The results from this study support an ecosystem value of > 2.0 mg/L, and indicate that the conservative Dutch risk assessment for AESs has at least a fivefold margin of safety.