21st Annual Meeting of the International Society of Exposure Science
Purpose: The reproductive toxicity of several phthalates leadsto regulatory measures for these plasticisers. However, only fewphthalates have been evaluated for their toxicological effects.Therefore, regulations exist only for a limited number of phthalates.It has been claimed that phthalates, which are structurally similarto already classified and regulated phthalates, possess comparablereprotoxic properties (especially concerning the male reproductivesystem). In order to compare the toxic potency of phthalates, it wasthe aim of this study to identify appropriate sensitive parametersfor reproductive effects of phthalates. Methods: The male reproductivetoxicity of dialkyl phthalates of side chains in the range of 3-8carbon atoms was reviewed based on about 200 publications inthe open literature. The reproductive toxic potential was analysedfor di-n-propyl-, di-iso-butyl-, di-n-butyl-, di-n-pentyl-, di-cyclohexyl-, di-n-hexyl-, di-iso-heptyl-, di-2-ethylhexyl-, di-n-heptyl-,di-n-octyl-, and di-iso-nonyl-phthalate. Adverse effects on variousendpoints of male fertility and offspring development were compared.Results: Selected phthalates with side chain lengths of 4-6C-atoms adversely affect male fertility with comparable potentialand potency. Overall, impairment of male development was morepronounced compared to the impairment of male fertility. Concerningfertility, adverse effects on sperm parameters and Sertolicells were the most sensitive endpoints. Concerning development,reduction of anogenital distance and changes in testosterone levelsin serum or testes were the most sensitive endpoints. Concerningdevelopment, doses inducing adverse effects were lower forphthalates with 4-6 C-atoms in the side chain when compared tophthalates with longer or shorter side chains.