Mutagenic and clastogenic potentials of styrene and styrene oxide

101 2 Sorsa, M., H. Vainio, T. Meretoja (t) and K. Linnainmaa, Department of Industrial Hygiene and Toxicology, Institute of Occupational Health, Haartmanink. 1, SF-00290 Helsinki 29 {Finland) Mutagenic and clastogenic potentials of styrene and styrene oxide During recent years evidence has been gained about possible delayed health risks of styrene, a vinyl benzene used in manufacturing polyester plastics. The clastogenic effects among workers exposed to styrene have earlier been reported: styrene-exposed men from plants manufacturing polyester plastics show a significantly higher incidence of chromosomal aberrations than control men. Also in experimental systems both styrene and its first mammalian metabolite, styrene oxide, show specific cytogenetic effects in vitro and in vivo both in mammals (rat, human lymphocyte cultures) and in plants (Allium). Both compounds have a strong c-mitotic effect in Allium, while induction of chromosome and chromatid breaks is more characteristic of styrene in all test systems. The mutagenic potentials of styrene and styrene oxide have earlier been demonstrated in the Ames test with Salmonella. Also in Drosophila, there is a slight increase of recessive lethals after exposure to atmospheric styrene. The above findings, the demonstration of mutagenic response in submammalian test systems, and observations of a significant increase of chromosomal aberrations among workers exposed to styrene as well as in experimental systems, speak to the need of a large-scale epidemiological search to find out the health risks of styrene in occupational exposure.

3 Hermann, M., N. Weill-Thevenet and M. Hofnung, Institut Pasteur, Toxicologie G~ndtique, 28 rue du Dr. Roux, 75015 Paris, and Institut Franqais du P~trole, Service de Biochimie, Paris {France) Studies on mutagenicity of lipophilic compounds The standard Ames test is performed in an hydrophilic medium to assay the mutagenic properties of compounds. This procedure cannot be used without modifications with lipophilic compounds such as mineral oils. Several techniques have been devised to adapt the Salmonella/microsome assay to oils. Standardizations of the methods have been made by measuring the mutagenicity of solutions of various polycyclic aromatic hydrocarbons (PAH) dissolved in non-mutagenic oils. Most of the PAH assayed by us are commonly found in mineral oils. The techniques allowed us to compare the mutagenicity of oils. This mutagenicity varies greatly depending on the origin and mode of treatment of the oil. Physico-chemical analysis of some oils showed that benzo(a)pyrene was very little or not involved in the mutagenic power of certain oils. The identification of the major mutagenic components of several oils is in progress.