Ingrid Bazin

Parabens are alkyl esters of p-hydroxybenzoic acid that could be encountered in various environmental waters; and there is little available information about the adverse effects of these compounds on aquatic organisms. Moreover, information concerning their levels and potential environmental long-term effects are currently missing. This paper aims at increasing the knowledge on the potential hazard of parabens. Four microorganism model systems (Vibrio fischeri, Photobacterium leiognathi, Daphnia magna and Tetrahymena thermophila) have been used for this purpose. In addition, estrogenicity has been studied for parabens and binary mixtures of estrogenic compounds and parabens by using a recombinant yeast estrogen screen assay (YES). Following the EU EMEA Environmental Risk Assessment guideline for classification of dangerous substances and considering the results obtained with Daphnia magna, methyl, ethyl and n-propyl parabens should be classified as harmful substances for aquatic organisms, whereas n-butyl and benzyl parabens as toxic substances. Concerning the biological activity, parabens are 8,000-900,000-fold less estrogenic than estradiol, the most estrogenic one being the aromatic compound benzylparaben. Higher estrogenic effect has been observed when estrogenic compounds have been added to parabens.