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Description of key information

90-day repeated dose toxicity study by inhalation conducted on alpha-pinene multiconstituent: NOAEC for male rats = 100 ppm

90-day repeated dose toxicity study by inhalation conducted on alpha-pinene multiconstituent: NOAEC for female rats = 200 ppm

90-day repeated dose toxicity study by inhalation conducted on alpha-pinene multiconstituent: NOAEC for female mice = 50 ppm

90-day repeated dose toxicity study by inhalation conducted on alpha-pinene multiconstituent: LOAEC for male mice = 100 ppm

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LOAEC
566.5 mg/m³
Study duration:
subchronic
Species:
mouse
Quality of whole database:
Study conducted similarly to OECD guideline 413
System:
male reproductive system
Organ:
cauda epididymis

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

In 2-week inhalation preliminary studies (rats and mice) animals were exposed to concentration of 800 and 1600 ppm of alpha-pinene.

 

In a 90-day inhalation study conducted by NTP similarly to OECD guideline 413, male rats exposed to alpha-pinene showed effects on renal and reproductive systems. The effects on kidneys are not relevant to humans as they are based on sex- and species-specific renal effects linked to alpha2µ-globulin accumulation. A decrease in sperm count in cauda epididymis at 200 and 400 ppm was observed. Therefore the NOAEC identified for male rats is 100 ppm.

However, the relevance of these effects can be questioned: first, the heat fixation at 65°C of caudae samples for sperm counts may have altered the integrity of the samples; secondly, these changes in sperm levels were not corroborated by other findings such as histopathological changes in other reproductive organs/tissues or other sperm parameters (motility, spermatid counts, etc.). In addition, animals were exposed whole body by inhalation, which likely resulted in systemic exposure much higher than intended exposure from target doses (animals likely exposed by oral route through grooming).

A lower body weight gain and death of 6 out of 10 females in the high dose group (400 ppm) were observed. A NOAEC could be defined in female rats at 200 ppm on the basis of mortality and a lower body weight gain.

 

In a 90-day inhalation study conducted by NTP similarly to OECD guideline 413, mice were exposed to alpha-pinene. Minimal to moderate hyperplasia have been observed in the transitional epithelium of the urinary bladder from 100 ppm in both sexes.

Decreased numbers of sperm per mg cauda in 200 and 400 ppm males and cauda sperm in 100, 200, and 400 ppm males were observed.

However, the relevance of these effects can be questioned: first, the heat fixation at 65°C of caudae samples for sperm counts may have altered the integrity of the samples; secondly, these changes in sperm levels were not corroborated by other findings such as histopathological changes in other reproductive organs/tissues or other sperm parameters (motility, spermatid counts, etc.). Also, these decreases might be secondary to stress induced by hyperplasia of bladder epithelium at the 3 highest doses. In addition,animals were exposed whole body by inhalation, which likely resulted in systemic exposure much higher than intended exposure from target doses (animals likely exposed by oral route through grooming). In a conservative approach, this effect was selected as the critical effect to calculate DNELs and a LOAEC was established for males at 100 ppm.

A NOAEC for female mice has been set at 50 ppm based on minimal to moderate hyperplasia observed in the transitional epithelium of the urinary bladder.

Justification for classification or non-classification

The CLP classification for Specific Target Organ Toxicity in Repeated Exposure is based on results found in rats therefore the results found in mice are not taken into account. The LOAEC in male rats reported in the study report is the lowest dose level tested, but it is not relevant to humans as it is based on sex- and species-specific renal effects linked to alpha2µ-globulin accumulation. When considering effects other than those on kidneys in males, a lower body weight gain at 400 ppm and decreased sperm count in cauda epididymis from 200 ppm were observed, therefore a conservative NOAEC for males could be defined at 100 ppm. A NOAEC could be defined in female rats at 200 ppm on the basis of mortality and a lower body weight gain at the next dose level when compared to controls.

Mortality was observed in females at 400 ppm, corresponding to 2.26 mg/L, which is above the limit concentration for classification (1 mg/L for vapours). The decreased sperm count in males is not relevant for STOT-RE classification and is further discussed in the reproductive toxicity endpoint summary. Also, it was observed from 200 ppm, corresponding to 1.13 mg/L, which is above the limit concentration for classification (1 mg/L for vapours).

Therefore, (-)-alpha-pinene does not need to be classified for Specific Target Organ Toxicity in Repeated Exposure according to CLP Regulation (EC) n° 1272/2008.