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Toxicological information

Neurotoxicity

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Description of key information

Acute CNS effects:

Hydrocarbons, C10 -C12, isoalkanes, <2% aromatics: NOAEC in rats = 1500 mg/m3

n-decane: NOAEC in rats = 1500 mg/m3 (based primarily on volatility)

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

Referenceopen allclose all

Endpoint:
neurotoxicity: acute inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1999/09/29-1999/10/22
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 this study was to evaluate the behavioral effects of exposure to Hydrocarbons, C10-C12, isoalkanes, <2% aromatics in rats. 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): 20-25
- Humidity (%): 33-50
- 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 Hydrocarbons, C10-C12, isoalkanes, <2% aromatics into stainless steel tubing using peristaltic pumps. The tubing was led through a water bath at 60 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 two total carbon analysers.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
two total carbon analysers
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 Hydrocarbons, C10-C12, isoalkanes, <2% aromatics 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:
Results of the behavioral tests showed some mild effects of exposure to Hydrocarbons, C10-C12, isoalkanes, <2% aromatics on learned performance measurements in the highest exposed test group (5 g/m3). Measures of performance speed were sensitive to the effects of Hydrocarbons, C10-C12, isoalkanes, <2% aromatics, while measures of discrimination accuracy and stimulus control were not affected. Correct choice latencies were slightly increased and only significant in the 5 g/m3 exposure group. Drink response latency was not significantly changed. No significant effects were observed in functional observational measurements and in measurements of motor activity.
Dose descriptor:
NOAEC
Effect level:
> 1 500 mg/m³ air (nominal)
Sex:
male
Remarks on result:
other:
Conclusions:
Short-term, high-level exposure to Hydrocarbons, C10-C12, isoalkanes, <2% aromatics induced mild, non-persistent neurobehavioral effects on measures of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m3. Exposure to 0.5 g/m3 or 1.5 g/m3 of Hydrocarbons, C10-C12, isoalkanes, <2% aromatics did not induce exposure-related neurobehavioral effects.
Executive summary:

Short-term, high-level exposure to Hydrocarbons, C10-C12, isoalkanes, <2% aromatics induced mild, non-persistent neurobehavioral effects on measures of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m3. Exposure to 0.5 g/m3 or 1.5 g/m3 of Hydrocarbons, C10-C12, isoalkanes, <2% aromatics did not induce exposure-related neurobehavioral effects.

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:
2 supporting acute studies available from structural analogues.

Effect on neurotoxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

No studies are available for Dodecane, however; neurotoxicity studies from structural analogues, Hydrocarbons, C10 -C12, isoalkanes, <2% aromatics and n-decane, are available.

 

Inhalation

In a supporting study (ExxonMobil, 2001), short-term, high-level exposure to Hydrocarbons, C10-C12, isoalkanes, <2% aromatics induced mild, non-persistent neurobehavioral effects on measures of learned performance. Effects were observed during or after 3 consecutive 8 hour exposures at the highest tested concentration of 5 g/m3. Exposure to 0.5 g/m3or 1.5 g/m3of Hydrocarbons, C10-C12, isoalkanes, <2% aromatics did not induce exposure-related neurobehavioral effects.

 

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.

Justification for classification or non-classification

Based on the available read across data, Dodecane is unlikely to present a hazard as a neurotoxicant.