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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
24 mg/m³
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
By inhalation
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
3
Dose descriptor starting point:
NOAEC
Value:
143 mg/m³
Modified dose descriptor starting point:
NOAEC
Value:
72 mg/m³
Explanation for the modification of the dose descriptor starting point:

Conversion of the inhalatory rat NOAEC (starting point) into in a corrected inhalatory NOAEC (modified starting point):

- assumptions (for workers): 8h exposure/day; inhalation absorption rat = inhalation absorption human

corrected NOAEC = NOAEC, inhal * (6 h/d) / (8 h/d) * (6.7 m3 (8h) / 10 m3 (8h)) = 143 mg/m3 * 0.75 * 0.67 =72 mg/m3

AF for dose response relationship:
1
Justification:
Starting point is a NOAEC. Thus, standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov 2012).
AF for differences in duration of exposure:
1
Justification:
In subchronic inhalation toxicity studies with DHN in rats and mice, animals were exposed for 6h on 5 days per week for a period of 3 months. The most sensitive species was the rat with NOAEC of 143.2 mg/m³ (25 ppm).
Increased liver weights and renal toxicity were observed at lowest test concentration in a 16-days repeated dose toxicity inhalation study (NTP 2005) and a subchronic 90-days study (NTP 2005) in rats. These effects were not observed in a chronic 2-years study (NTP 2005) therefore no additional safety factor is considered necessary to extrapolate from subchronic experimental exposure to chronic worker exposure.
AF for interspecies differences (allometric scaling):
1
Justification:
According to ECHA TGD an allometric scaling factor is not applicable when setting an inhalation DNEL based on an inhalation animal study (see Appendix R.8-2 of TGD (ECHA, Nov. 2012)), therefore AF 1 is chosen.
AF for other interspecies differences:
1
Justification:
Rodents like the rat are in general more sensitive compared to humans as the rat`s ventilation frequency is higher. Therefore, as a general rule a factor of 1 for remaining interspecies differences provides sufficient protection.
AF for intraspecies differences:
3
Justification:
Default safety factor accounting for intraspecies differences in susceptibility (factor 3) are assumed. The AF was refined according to ECETOC, 2003 and draft guidance 2010.
AF for the quality of the whole database:
1
Justification:
Because of good/standard quality of the database the standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov. 2012).
AF for remaining uncertainties:
1
Justification:
No further assessment factors are considered necessary.
Acute/short term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
24 mg/m³
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
By inhalation
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
DNEL extrapolated from long term DNEL

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
repeated dose toxicity
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
repeated dose toxicity
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
3.33 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
60
Dose descriptor starting point:
NOAEL
Value:
200 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
Value:
200 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

Route to route extrapolation

Toxicokinetik studies with experimental animals (rats) indicated that oral absorption was complete. As a worst case consideration dermal absorption is considered as 100 %.

AF for dose response relationship:
1
Justification:
Starting point is a NOAEL. Thus, standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov. 2012).
AF for differences in duration of exposure:
2
Justification:
Based on the EOGRTS (OECD 443) a NOAEL of 200 mg/kg bw/day with the default exposure duration assessment factor of 2 (subchronic-chronic) is considered.
AF for interspecies differences (allometric scaling):
4
Justification:
According to ECHA TGD (see section 8.4.3.1 of TGD; ECHA, Nov. 2012) for interspecies extrapolation the default factor of 4 for metabolic differences between rat and humans is considered for both the oral and the dermal exposure route.
AF for other interspecies differences:
2.5
Justification:
A further assessment factor of 2.5 is used by default for dermal/oral exposure according to ECHA TGD (ECHA, Nov. 2012).
AF for intraspecies differences:
3
Justification:
Default safety factor accounting for intraspecies differences in susceptibility (factor 3) are assumed. The AF was refined according to ECETOC, 2003 and draft guidance 2010.
AF for the quality of the whole database:
1
Justification:
Because of good/standard quality of the database the standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov. 2012).
AF for remaining uncertainties:
1
Justification:
No further assessment factors are considered necessary.
Acute/short term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
13.5 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
DNEL extrapolated from long term DNEL

Local effects

Long term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
skin irritation/corrosion
Acute/short term exposure
Hazard assessment conclusion:
medium hazard (no threshold derived)
Most sensitive endpoint:
skin irritation/corrosion

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
medium hazard (no threshold derived)

Additional information - workers

Derivation of DNELacute


Decahydronaphthalene was of low toxicity in experimental animals upon oral or dermal application at high dose levels, LD50were 2850 and 16800 mg/kg bw.


A LC50value of 710 ppm corresponding to 4.08 mg/L was established.


DHN induced irreversible irritation in a rabbit skin, requires labelling as corrosive.


Derivation of DNELlong term


Starting point


In an EOGRTS oral according to OECD 443 the NOAEL was determined at 200 mg/kg bw/d with no adverse systemic effects observed in the F0 and F1 generation. Mortalities were noted in dams in a mouse embryotoxicity study upon oral administration of 2700 mg/ DHN/kg bw/day on gestation days 6-13.









In a 90-day inhalation study (US NTP 2005) urinalysis showed significant findings (increase in lactate dehydrogenase/creatinine ratio and in aspartate aminotransferase/creatinine ratio) in male and female rats exposed to 25 ppm and greater. Absolute and/or relative kidney and liver weights of male rats exposed to 50 ppm were increased. Females were not affected. So, the changes in enzyme urine levels in female rats are not adverse effects, because they are not related to any simultaneous increase of kidney weight damage. Therefore, 25 ppm (143 mg/m3) is determined to be the no observed effect concentration (NOAEC) in female rats in this 90-day study and is used as starting point for the derivation of the DNELlong term.


Conversion of the inhalatory rat NOAEC (starting point) into in a corrected inhalatory NOAEC (modified starting point):


- assumptions (for workers): 8h exposure/day; inhalation absorption rat = inhalation absorption human


corrected NOAEC = NOAEC, inhal * (6 h/d) / (8 h/d) * (6.7 m3 (8h) / 10 m3 (8h)) = 143 mg/m3 * 0.75 * 0.67 = 72 mg/m3


 
















Furthermore, increase liver weight even at the lowest dose level (LOAEC) of 25 ppm (143 mg/m³) in rats was observed in a 16-day inhalation study with rats (US NTP 2005). As this effect was not observed in the 90-day inhalation study (see above) it indicates that this effect is rather reversible and hence the LOAEC was not used as starting point for the derivation of the DNELlong term.









 


No adverse local effects were reported at dose levels up to 2280 mg/m³.


 


DNELlong term


In an in vivo mouse micronucleus assay DHN showed only slight clastogenic activity in male mice. Incidences of adenoma or carcinoma in both rats and mice were not significantly increased with the exception of cortical renal tubule adenoma in male rats. Based on the observations in repeated dose studies of hyaline droplet formation it is concluded that the mechanism of induction of these adenomas is specific to male rats and of no relevance to human cancer risk.


 


Route to route extrapolation


Toxicokinetic studies with experimental animals (rats) indicated that oral absorption was complete. As a worst case consideration dermal absorption is considered as 100%. Absorption via the inhalation route is considered as 100% by default.


 


Exposure duration extrapolation


Oral and dermal route


Based on an EOGRTS oral according toOECD 433 a NOAEL of 200 mg/kg bw/day with the default exposure duration assessment factor of 2 (subchronic-chronic) is considered.


 


Inhalation route


In subchronic inhalation toxicity studies with DHN in rats and mice, animals were exposed for 6h on 5 days per week for a period of 3 months. The most sensitive species was the rat with NOAEC of 143.2 mg/m³ (25 ppm).


Increased liver weights and renal toxicity were observed at lowest test concentration in a 16-days repeated dose toxicity inhalation study (NTP 2005) and a subchronic 90-days study (NTP 2005) in rats. These effects were not observed in a chronic 2-years study (NTP 2005) therefore no additional safety factor is considered necessary to extrapolate from subchronic experimental exposure to chronic worker exposure.


 


Interspecies extrapolation


For interspecies extrapolation the default factor of 4 for metabolic differences between rat and humans is considered for both the oral and the dermal exposure route. This factor is by default not considered relevant for inhalation exposure. In addition, a further safety factor of 2.5 is used by default for dermal/oral exposure.


Rodents like the rat are in general more sensitive compared to humans as the rat`s ventilation frequency is higher. Therefore, as a general rule a factor of 1 for remaining interspecies differences provides sufficient protection.


 


Intra-species assessment factors


Default safety factor accounting for intraspecies differences in susceptibility (factor 3) are assumed. The AF was refined according to ECETOC, 2003 and draft guidance 2010.


 


Additional safety factors


Toxicokinetic information indicated that there is no potential for accumulation.


No further assessment factors are considered necessary.


   


 


DNELlong-term


Overall assessment factor is 60 for workers for dermal exposure. For inhalation exposure overall assessment factor of 6 is considered for workers.


Thus, the DNELlong-term calculated for workers are 3.33 mg/kg bw/day for the dermal route and 24 mg/m³ for the inhalation route.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
1 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
200
Dose descriptor starting point:
NOAEL
Value:
200 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

No route -to-route-extrapolation needed

AF for dose response relationship:
1
Justification:
Starting point for the DNEL calculation is a NOAEL. Thus standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov. 2012)
AF for differences in duration of exposure:
2
Justification:
A assessment factor 2 is suggested by the ECHA TGD for exposure duration from subchronic to chronic (see section R 8.4.3.1, Table R.8-5) (ECHA, Nov. 2012).
AF for interspecies differences (allometric scaling):
4
Justification:
An allometric scaling factor of 4 is suggested by the ECHA TGD (see section 8.4.3.1 of TGD; ECHA, Nov. 2012) for interspecies differences.
AF for other interspecies differences:
2.5
Justification:
A factor of 2.5 is suggested by the ECHA TGD (ECHA, Nov. 2012) for remaining interspecies differences.
AF for intraspecies differences:
10
Justification:
For intraspecies variability, the default assessment factor for the general population is 10 (ECHA, Nov. 2012).
AF for the quality of the whole database:
1
Justification:
Because of good/standard quality of the database the standard assessment factor 1 is used as described in chapter R 8.4.3.1 of TGD (ECHA, Nov. 2012).
AF for remaining uncertainties:
1
Justification:
No further assessment factors are considered necessary.
Acute/short term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
1 mg/kg bw/day
Most sensitive endpoint:
repeated dose toxicity
Route of original study:
Oral
DNEL related information
DNEL extrapolated from long term DNEL

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - General Population

Decahydronaphthalene is not intended for consumer uses. Therefore, the exposure of consumers to decahydronaphthalene via consumer products is not given. An exposure of the general population via the environment might occur through ingestion of foodstuff or drinking water. Therefore, an oral DNEL systemic, long-term for general population is derived.