Styrene

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Klimisch code: 1. Reliable without restrictions. “Key study” Well-organised and reported study, referred in reliable sources of peer-reviewed scientific literature.

Data source

Reference

Reference Type:

publication

Title:

Teratologic evaluation of styrene given to rats and rabbits by inhalation or by gavage.

Author:

Murray et al

Year:

1978

Bibliographic source:

Toxicology, Vol.11: 335 -343

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Principles of method if other than guideline:

Pre-natal Developmental Toxicity Study in Rats by Inhalation
Study investigated: toxicity of styrene to embryonal and fetal development through pre-natal exposure via whole-body inhalation

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Styrene

EC Number:

202-851-5

EC Name:

Styrene

Cas Number:

100-42-5

Molecular formula:

C8H8

IUPAC Name:

ethenylbenzene

Results and discussion

Results (fetuses)

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Results

 

LOAEC maternal toxicity:

300 ppm (1278 mg/m3) (decreased body weight)

 

NOAEC developmental toxicity:

600 ppm (2556 mg/m3)

 

Maternal data:

 

Mortality:

At 300 ppm: 1 of 30 rats died on gestation day 20 (cause of death not determined). No deaths or early deliveries were observed in any other groups.

 

No signs of altered appearance of behavior were observed.

 

Body weight:

At ≥300 ppm: Decreased weight gains (associated with decreased food consumption) on gestation days 6 through 9.

 

Water consumption:

At ≥300 ppm: Increased water consumption on gestation days 9 through 20.

 

Number of implantations:

No treatment-related effects on the incidence of pregnancy were observed.

 

Pre and post implantation loss:

No treatment-related effects on the average number of live foetuses or resorptions per litter were observed.

 

Fetal data:

 

Litter size and weights:

No treatment-related effects on the mean foetal body weights were observed.

 

At 300 ppm: statistically significant decrease in the average foetal crown-rump length was observed.

 

Grossly visible abnormalities, external, soft tissue and skeletal abnormalities:

No treatment-related effects on the incidence of external, visceral, and skeletal malformations were observed.

Statictically significant increased incidence of a few skeletal variants (not considered to be malformations), including lumbar spurs, delayed ossification of sternebrae and vertebral centra, were observed. This occurrence was consistent with historical control data.

Applicant's summary and conclusion

Conclusions:

No teratogenic toxicity of styrene was observed in rats through pre-natal exposure via whole-body inhalation.
The LOAEC for maternal toxicity was observed at 300 ppm (decreased body weight).
The NOAEC for fetal toxicity/embriotoxicity was observed at 600 ppm.