English Abstract Circa 30% of the new substances that have to be
notified for an evaluation of the potential hazards/risks have a poor water
solubility (< 1mg/l). A problem is recognized in the interpretation of
results of aquatic toxicity tests carried out with these compounds since the
current OECD and EC guidelines give only little guidance to the testing of
these compounds. This document intends to give guidance for the
interpretation of results obtained from these tests for organic compounds.
A modification of the current EC classification of compounds on the basis of
environmental effects for the aquatic environment is proposed, based on the
toxicity of a compound rather than on its water solubility. Some
recommendations for the ecotoxicological risk evaluation of poorly water
soluble compounds are presented.