But-2-yne-1,4-diol

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Dose descriptor:

NOAEL

40 mg/kg bw/day

Additional information

Toxicity to reproduction was investigated in a GLP, OECD 415 Guideline study using concentrations of 1, 7.6, and 40 mg/kg body weight/day (BASF AG, 1999).There were no indications from the clinical and pathological examinations that the administration of 1,4 -Butynediol (B3D) had adverse effects on reproductive performance or fertility of the F0 parental animals of all substance-treated groups. Estrous cycle data, mating behavior,conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights, gross and histopathological findings of these organs revealed no substance-related adverse effects. Most of the F0 parental rats proved to be fertile. The scattered occurrence of individual infertile rats throughout the different dose groups did not suggest any relation to treatment.

Short description of key information:

NOAEL for reproductive performance and fertility = 40 mg/kg bw/day

Effects on developmental toxicity

Description of key information

NOAEL for developmental toxicity = 40 mg/kg bw/day

Effect on developmental toxicity: via oral route

Dose descriptor:

NOAEL

40 mg/kg bw/day

Additional information

Developmental toxicity was assessed in a GLP, OECD 414 Guideline study using concentrations of 10, 40, and 80 mg/kg body weight/day (BG Chemie, 1995). Under the conditions of this full-scale prenatal toxicity study, 2-Butyne-l,4-diol caused overt signs of maternal toxicity at 80 mg/kg bodyweight/day substantiated by reduced food consumption, impaired body weight gains, the intercurrent death of one dam and some adverse clinical signs (all these findings occurred at the beginning of the treatment period). Forty (40) and 10 mg/kg body weight/day were tolerated by the dams without any substance-induced findings. Marginal signs of developmental toxicity were observed at the highest dose level (80 mg/kg body weight/day), substantiated by an increased number of affected fetuses/litter with accessory 14th rib(s), a skeletal variation. No substance-induced teratogenic effects, however, were observed up to and including the dose of 80 mg/kg body weight/day and there were no signs of embryo-/fetotoxicity at 40 mg/kg and 10 mg/kg bodyweight/day. For this prenatal toxicity study in rats, the no observed adverse effect level (NOAEL) for dams and fetuses is 40 mg/kg body weight/day.

Justification for classification or non-classification

1,4 -Butynediol (B3D) should not be classified as a reproductive or developmental hazard under either the EU DSD classification criteria (Directive 67/548/EEC) or the EU CLP classification criteria (Regulation (EC) 1272/2008) on the basis of negative findings observed in a GLP OECD 415 guideline study (BASF AG, 1999) and a GLP OECD 414 guideline study (BG Chemie, 1995), with rats, at doses up to 40 mg/kg-bw.