M3 AM Ecological Risk Assessment (Part 1)
Monday, 14 November 2005: 8:00 AM - 11:40 AM in Ballroom 3

(BEL-1123-267692) Risk Overview of a New and Advanced Global Environmental Assessment of Alcohol Ethoxylate Surfactant Mixtures.

Belanger, S¹, Boeije, G², Cano, M³, Dorn, P³, Eadsforth, C⁴, Federle, T¹, Gumbel, H⁴, Marshall, S⁵, Morrall, S¹, Toy, R⁷, ¹ Procter & Gamble Company, USA² Procter & Gamble, Brussels, Belgium³ Shell Global Solutions, USA⁴ Shell Global Solutions, UK⁵ BASF, Ludwigshafen, Germany⁷ Shell Chemicals, Ltd., UK

ABSTRACT- Alcohol ethoxylates (AE), a class of nonionic surfactants, are produced at >1 million metric tons/year globally. Commercial alcohol ethoxylate surfactants are mixtures that range from 12 to 18 alkyl carbons with varying degrees of ethylene oxide (ethoxylate) substitution that range from no (zero) to 18 units per molecule. Risk assessments conducted in the 1990's in both Europe and the US were updated based on collective advancements in analytical methods, ecotoxicology and environmental fate studies and data analysis techniques. The environmental fate and effects of AE are linked to the pattern (environmental fingerprint) of the AE homologue distribution in a mixture. New analytical methods enable detailed understanding of the distribution of AE homologues in sewage treatment plant effluents at sub-part-per-billion levels (ng/L). These methods were deployed in waste water treatment plant effluent monitoring studies across Europe, Canada and the USA. Fate studies were performed to understand sorptive behavior of AE in effluents and receiving waters. Evaluations using benchtop sewage treatment plant test systems and batch die-away studies provided detailed insight into metabolism of AE and its short-lived intermediates. Chronic toxicity QSARs for algae, invertebrates and fish from laboratory and stream mesocosm studies were developed to allow quantitative interpretation of the relationships between commercial mixtures and actual environmental distributions. Using species sensitivity distributions to estimate PNECs for each homologue, and then applying a concentration addition approach, we calculated a toxic unit fraction for individual AE homologues. These were then summed to obtain the toxic unit fraction for the whole effluent distribution as a descriptor for the risk potential of AEs. Collectively, the application of cutting edge technology has resulted in an updated global environmental risk assessment of AE. This process re-affirmed the very low risk of AE to aquatic life in all monitored geographies.

Key words: risk assessment, Alcohol Ethoxylate Surfactant