1,1-dimethylheptanethiol

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

No reproductive toxicity study was identified for 1,1 -dimethylheptanethiol.

Effects on developmental toxicity

Description of key information

Treatment with tert-dodecanethiol by whole body inhalation at an actual exposure level of 88.6 ppm (733 mg/m3 or 0.733 mg/L) or less did not produce a teratogenic effect in mice or rats.

Effect on developmental toxicity: via inhalation route

Dose descriptor:

NOAEC

733 mg/m³

Additional information

No key developmental toxicity data are available for 1,1-dimethylheptanethiol. Several criteria justify the use of the read across approach to fill data gaps for 1,1-dimethylheptanethiol using tert-dodecanethiol as an analog. 1,1-dimethylheptanethiol, like tert-dodecanethiol, is a heavy mercaptan and has similar physiochemical properties. Hence, the toxicological properties of both these substances are also expected to be similar. Key read across data from tert-dodecanethiol was therefore used to evaluate the developmental toxicity potential.

An inhalation teratology study (Schardein, 1983; Klimisch score = 2) was conducted on tert-dodecanethiol in pregnant Charles River CD-1 mice and COBS-CD rats at 22.7 and 88.6 ppm (188 mg/m³ or 0.188 mg/Land 733 mg/m³ or 0.733 mg/L), as chemically analysed concentration levels. The high dose level was a saturated vapor concentration for this compound. Mice were exposed on gestation days 6 through 16 and rats were exposed on gestation days 6 through 19. Exposures were conducted daily for 6 hours. Caesarean sections were conducted on gestation day 17 for mice and gestation day 20 for rats. One mouse died at the 22.7 ppm level and one rat died at the 88.6 ppm level. The cause of death could not be determined for either animal. In mice, body weights in the low dose group were depressed through the first week of exposure. Body weight gains in rats appeared to have a dose related depression. Mice exhibited a slight exposure related increase in mean postimplantation loss which was not statistically significant. Three control mice exhibited total implant resorptions, while both test groups contained five mice each exhibiting total implant resorptions. There was a corresponding slight reduction in the mean number of viable foetuses for the two treatment groups. The mean number of total implants, corporea lutea, fetal body weight and fetal sex distribution in mice were comparable to control values. No statistically significant differences for rats were noted for all Caesarean section observations in treated vs. control animals. No statistically significant or treatment related foetal malformations were noted for mice or rats treated with tert-dodecanethiol. Up to a saturated vapor concentration of 88.6 ppm, tert-dodecanethiol was not found to be teratogenic.

The developmental toxicity NOAEC was determined to be ≥ 88.6 ppm (733 mg/m³or 0.733 mg/L)

Toxicity to reproduction: other studies

Additional information

In 28 -day repeated inhalation toxicity studies in rats, mice and dogs (Ulrich, 1985; Klimisch score = 2), no histological effect was observed on the reproductive organs.

Justification for classification or non-classification

According to the available data and the criteria for classification of REGULATION (EC) No 1272/2008and the EU Directive Dir 67/548/EEC, no classification is warranted for reproductive and developmental toxicity.