Hydrogen sulphide

Specific investigations: other studies

Additional information

There is a combined systemic- and reproduction toxicity study according to OECD 421 with H2S availiable. In this study not only the toxicity to reproduction was investigated but also the systemic toxicity. Specific attention was put on the histopathology of the nose and its epitheleum as first target for a respiratory irritation.

In contrast to all the other specific investigations on respiratory tract irritation in literature an accepted guideline-conform procedure for the evaluation of respiratory tract irritation has been used. In this GLP study Dorman et al. (2000) examined the effects of an inhalation exposure to H2S. According to OECD 421 groups of 12 male and 12 female Sprague-Dawley rats were exposed to hydrogen sulfide at 0, 10, 30, or 80 ppm 6 h/day, 7 days/week for 2 weeks before breeding. Exposures continued during a 2-week mating period and then on GD 0-19. Exposure of the dams and pups (eight rats per litter after culling) resumed from PND 5 to PND 18. Adult male rats were exposed on 70 consecutive days.

The extensive histopathologic examination of the nose revealed a significant increase in nasal lesions of the olfactory mucosa. A markedly increased incidence of olfactory neuron loss and basal cell hyperplasia was found following exposure to 30 and 80 ppm H2S. The no observed adverse effect level for these respiratory lesions was 10 ppm.

All the other studies reported in literature were not performed according to a guideline and used much shorter exposition times per day as the study of Dorman et al. (2000). Therefore their results are not comparable to the guideline study and these studies are judged as "not reliable" or as "not assignable" and the results of these studies are not used for the evaluation of the respiratory tract irritation of H2S.