[Occupational risk after repeated skin exposure to styrene]

The use of styrene in the production and processing of polymers, varnishes and paints is a prerequisite for a broad skin contact with the solvent, hence conditions for occupational effect on the workers, manifested with frequent contact toxic dermatitis. That determined the scope of this work, aiming at the specifying of the occupational risk in case of repeated dermal contact with styrene. The experiment was carried out in the course of 28 days on 70 albino male rats, treated daily, dermally with 4 ml/kg and 8 ml/kg from the substance and on groups with a following 14--day rehabilitation. The following methods were used in the investigation: histological (H.E.), histochemical (Sudan III, Sudan schwartz and PAS-reactions under the control of alpha-amilase), enzyme-histochemical (activity of alkaline phosphatase, acid phosphatases, ATP, SDH, LDH and G16PDH) and electron microscopic. The repeated skin application of styrene was established to induce changes in the organism of the experimental animals, localized mainly in the liver and carrying the character of fatty dystrophia. The latter is directly proportional to the dose applied and the exposure duration. After a 14-day rehabilitation period, the dystrophia abates and the processes of proliferation and regeneration predominate in the organ, regardless of the enzyme disorders established in the oxidation-reduction processes of liver, with the higher styrene dose (8 ml/kg). The authors presume that the dynamic follow up of the adaptation mechanisms in liver, in case of repeated dermal contact with styrene, determines reversible tissue deviations in organism of the experimental animals, being dose-effect dependent. The authors are in the opinion that the occupational risk in production and processing of polystyrene is minimum when observing the sanitary instructions for safe contact.