Alkanes, C11-12

Neurotoxicity

Key value for chemical safety assessment

Effect on neurotoxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no study available

Effect on neurotoxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

neurotoxicity: acute inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1998/03/11-1998/04/03

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well-documented study report which meets basic scientific principles: GLP.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

Principles of method if other than guideline:

The aim of the study was to evaluate the behavioral effects of exposure to n-decane in rats and to determine internal levels of exposure at which effects occur. Test methods included selected functional observational measures, automated motor activity assessment and visual discrimination performance.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: WAG/RijCrlBR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deuschland, Sulzfeld, Germany
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-21
- Humidity (%): 40-65
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Vehicle:

unchanged (no vehicle)

Details on exposure:

Test atmosphere was generated by pumping liquid n-decane into stainless steel tubing using peristaltic pumps. The tubing was led through a water bath at 86 deg C and the resulting vapour was transported with an air stream from a compressed air source and added to the main airflow system. The test atmospheres were analysed by a total carbon analyser.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

total carbon analyser

Duration of treatment / exposure:

8 hours

Frequency of treatment:

3 days

Remarks:

Doses / Concentrations:
0 (air), 0.5 g/m3 (85ppm), 1.5 g/m3 (260ppm), 5 g/m3 (860ppm)
Basis:
nominal conc.

No. of animals per sex per dose:

8 animals

Control animals:

yes, concurrent no treatment

Details on study design:

Animals were exposed to the test atmosphere in modified H100 inhalation chambers Hazleton System Inc., USA). Each chamber was fitted with a manometer that allowed monitoring the slightly negative pressure inside. Three test groups (with one control) comprising of 8 rats each were exposed to n-decane at different concentrations including: 0 (air), 0.5 g/m3 (85ppm), 1.5 g/m3 (260ppm), 5 g/m3 (860ppm). Animals were exposed to the test atmosphere 8 hours/day for 3 consecutive days. All rats were checked for health and viability at least once daily. Body weight was recorded during randomization on days of testing.

Details on results:

Functional observations indicated a significant reduction in forelimb grip-strength in the highest exposure group (5 g/m3) after the third exposure (8 h). Results of visual discrimination testing indicated mild n-decane induced disturbances in measures of learned performance. Measures of performance sped were sensitive to the effects of n-decane. The effects were reversible as demonstrated by the absence of significant differences in post-test measurements.

Dose descriptor:

NOAEC

Effect level:

>= 1 500 mg/m³ air (nominal)

Sex:

male

Remarks on result:

other:

Conclusions:

Short-term, high-level exposure to n-decane induced mild, reversible neurobehavioral effects on functional observations and measurements of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m3 of n-decane. Exposure to 0.5 g/m3 or 1.5 g/m3 of n-decane did not induce exposure-related neurobehavioral effects.

Executive summary:

Short-term, high-level exposure to n-decane induced mild, reversible neurobehavioral effects on functional observations and measurements of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m³ of n-decane. Exposure to 0.5 g/m³ or 1.5 g/m³ of n-decane did not induce exposure-related neurobehavioral effects.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

1 500 mg/m³

Study duration:

subacute

Species:

rat

Quality of whole database:

One supporting acute read across study from a structural analogue available for assessment.

Effect on neurotoxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

2 000 mg/kg bw/day

Study duration:

subacute

Species:

rabbit

Quality of whole database:

One supporting acute read across study from a structural analogue available for assessment.

Additional information

There is no neurotoxicity data available for Hydrocarbons, C11-C12, n-alkanes, <2% aromatics. However, supporting studies are available for structural analogues, n-decane and Hydrocarbons, C11-C14, n-alkanes, <2% aromatics and presented in the dossier. This data is read across to Hydrocarbons, C11-C12, n-alkanes, <2% aromatics based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

 

Inhalation

 

n-decane

In a supporting study (ExxonMobil, 1999), short-term, high-level exposure to n-decane induced mild, reversible neurobehavioral effects on functional observations and measurements of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m³of n-decane. Exposure to 0.5 g/m³or 1.5 g/m³of n-decane did not induce exposure-related neurobehavioral effects.

 

Dermal

 

Hydrocarbons, C11-C14, n-alkanes, <2% aromatics

A supporting study (ExxonMobil, 1993) was conducted to assess the dermal irritation potential and systemic toxicity of repeated topical application of the test material (Hydrocarbons, C11-C14, n-alkanes, <2% aromatics) at dose levels of 500, 1000, and 2000 mg/kg in the rabbit when administered daily for 7 days. Four groups consisting of 2 rabbits/sex/group were used. To serve as a comparison control, one group of animals was treated with n-hexane. Dermal application of 2000 mg/kg test material for seven days did not cause any gross signs of neurotoxicity or any clinical signs except for skin irritation, with erythema ranging from very slight to severe. All animals survived to study termination; NOAEL >2000 mg/kg.

Justification for classification or non-classification

Based on the available read across data, Hydrocarbons, C11-C12, n-alkanes, <2% aromatics is unlikely to present a hazard as a neurotoxicant.