Alcohol Ethoxylate (detergents) Risk Assessment Document

ABSTRACT

This document provides the results of the ecological risk assessment of alcohol ethoxylate (hereinafter “AE”, synonym: polyoxyethylene alkyl ether), a major non-ionic surfactant, conducted by the Research Center for Chemical Risk Management (CRM), the National Institute of Advanced Industrial Science and Technology (AIST). 

In Japan, this is the first comprehensive risk assessment that has revealed the current status of ecological risk in aquatic environment of AE as a mixture of homologues. The key features of AE risk assessment include the following: 

(1) To aim at a persuasive deduction based on solid theories and actual data, AE risk assessment is developed with conservative analyses of the actual data obtained for this risk assessment, as well as with original analyses applying newly developed methods and model estimations. 

(2) To aim at a homologue-based ecological risk assessment of AE with consideration to the differences among homologues, an estimation method to assess the risk of AE as a mixture of homologues, is proposed. This method is expected to be applicable for risk estimation of other mixtures similar to AE of which each homologue has similar mechanisms of toxicity.

(3) Since the ecotoxicity data of individual homologues are unavailable, a neural network model has been developed to predict the ecotoxicity for each homologue on organisms in the environment based on existing data. The method used to develop this model is expected to be applicable for risk assessment of other chemical substances whose ecotoxicity information is not presently available. 

(4) To assess the ecological risk defined as the adverse effects on the persistence of fish populations, an extrapolation method has been developed, which enables to estimate the threshold concentrations of effects on the persistence of fish populations for each homologue with limited ecotoxicity data (acute LC50/EC50 and chronic NOEC). It is expected that population-level ecological risk assessments for many other chemical substances with limited ecotoxicity data become feasible. 

(5) The first monitoring in Japan was conducted using LC/MS assay by bipyridinium derivatives (hereinafter “Pyr+/LC/MS method”), the latest analytical method for quantification of AE homologues, which revealed the compositions of AE homologues in commercial detergents marketed in Japan, influent and effluent of sewage treatment plants, and in aquatic environment. In addition, the data from the monitoring provided the information on both of the exposure concentrations and the half-life parameters for each homologue of AE in river water. These findings are the basic information required to elucidate AE ecological risk on a homologue-based, and are the highly valuable data obtained for the first time in Japan. 

(6) Attempts are made to quantify the relationship of risk trade-off and to evaluate its cost-effectiveness involved in the alternative use of AE that has been implemented to reduce the risk of nonylphenol ethoxylate (hereinafter “NPE”). 

(7) A methodological approach for ecological risk assessment including the screening-level risk assessment by species sensitivity distribution analysis and the risk characterization by effect analysis on the persistence of fish population is demonstrated. 

(8) Risk management measures feasible for national and local governments, industries, manufacturers and consumers are respectively recommended. 

Summary [PDF file, 405KB] 12 Feb. 2009