Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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:
2.48 mg/m³
Most sensitive endpoint:
genetic toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
1
Dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.507 mg/kg bw/day
Modified dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
2.48 mg/m³
Explanation for the modification of the dose descriptor starting point:

The oral safety limits (please refer to 'Additional information') were converted into the corrected inhalatory safety limits. Therefore, the default values of the ECHA Guidance on information requirements and chemical safety assessment Chapter R.8: Characterisation of dose [concentration]-response for human health (ECHA 2012) were used. The standard respiratory factor for human of 0.2 L/min/kg bw (Table R.8-2) was calculated for an 8 h working day (0.096 m³/kg bw/day). Further correction is done for work under light activity (standard respiratory volume in humans (6.7 m³/person) / worker respiratory volume (10 m³/person)) and for exposure conditions of workers (7 days / 5 working days = 1.4). Furthermore, it was taken into account that the inhalative absorption rate should be by a factor of 2 higher than the oral absorption as worst-case assumption. Thus, a factor of 0.5 is included.


Corrected starting point = 0.507 mg/kg bw/d x 1/0.096 m³/kg bw/d x 0.5 x (6.7 m³/10 m³) x 1.4 = 2.48 mg/m³


 

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

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.69 mg/m³
Most sensitive endpoint:
irritation (respiratory tract)
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
5
Dose descriptor:
NOAEC
Value:
3 mg/m³
AF for dose response relationship:
1
Justification:
A NOAEC is used as PoD
AF for differences in duration of exposure:
1
Justification:
There is specific evidence that increasing exposure duration does not increase the incidence or severity of adverse effects of the relevant source substance zinc oxide (5d-14d-90d data). Please refer also to the disseminated registration dossier of zinc oxide.
AF for interspecies differences (allometric scaling):
1
Justification:
not needed for inhalation DNEL as already covered by the correction of the starting point.
AF for other interspecies differences:
1
Justification:
Rats considered more sensitive than humans for inhaled inorganic particles.
AF for intraspecies differences:
5
Justification:
default for workers
AF for the quality of the whole database:
1
Justification:
Good quality, as a GLP study similar to OECD Test Guideline is used as PoD.
AF for remaining uncertainties:
1
Justification:
no remaining uncertainties
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

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

The starting point is corrected for a dermal absorption rate of 2 %, which is the generally agreed absorption rate for zinc compounds. The oral absorption is considered 100 % as worst-case. Further correction is done for the exposure conditions of workers (7 days / 5 working days = 1.4).


0.507 mg/kg bw/d x 100 %/2 % x 1.4= 35.49 mg/kg bw/d

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

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
low hazard (no threshold derived)

Additional information - workers

Systemic Long-term DNELs - PoD


A justification for the rationale behind the used PoD is found in the document 'Justification for a thresholded genotoxicity level of (anhydrous) Zinc borate' attached under Section 13.


An alternative way to derive a “safety limit” for anhydrous zinc borate (AZB) is to use the tolerable upper intake level (UL) derived/published by EFSA in 2006.


They derived an UL for zinc to be 25 mg per day per adult person.


Assuming that



  1. only zinc is responsible for adverse effects, at least in our current context of genotoxicity

  2. a person has 70 kg body weight;

  3. average alimentary zinc intake is 12.5 mg per person per day in the EU

  4. and taking into account the zinc concentration in AZB


the resulting “tolerable daily intake” of AZB would be 0.507 mg/kg bw AZB


The calculation is as follows:


zinc concentration in AZB
Zinc borate anhydrous (AZB): M(B6O11Zn2) = 371.64 g/mol.
Zinc concentration in AZB: M(Zn2) = 130.78 g/mol => 35.19%


UL Zinc per kg bw
UL Zinc (EFSA, 2006) = 25 mg/d for adults, corresponding to 357 µg/kg bw/d (assuming 70 kg bw).


Assuming no additional dietary Zn intake:
25 mg Zn/person => 25 mg/35.19% x 100% = 71.04 mg AZB/person = 1.015 mg/kg bw/d (assuming 70 kg bw).


Assuming average (mean) 12.5 mg dietary Zn intake per day per person (EFSA, 2006):


=> “residual tolerable” daily zinc intake


12.5 mg Zn/person => (12.5 mg/35.19%) x 100% = 35.52 mg AZB/person = 0.507 mg/kg bw/d AZB (assuming 70 kg bw)


 


Literature and References


EFSA (2006). Tolerable Upper Intake Levels for vitamins and minerals, Scientific Committee on Food, Scientific Panel on Dietetic Products, Nutrition and Allergies, February 2006, ISBN: 92-9199-014-0

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.88 mg/m³
Most sensitive endpoint:
genetic toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
1
Dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.507 mg/kg bw/day
Modified dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.88 mg/m³
Explanation for the modification of the dose descriptor starting point:

The oral safety limits (please refer to 'Additional information') were converted into the corrected inhalatory safety limits. Therefore, the default values of the ECHA Guidance on information requirements and chemical safety assessment Chapter R.8: Characterisation of dose [concentration]-response for human health (ECHA 2012) were used. The standard respiratory factor for human of 0.2 L/min/kg bw (Table R.8-2) was calculated for a 24 h day (0.288 m³/kg bw/d). Furthermore, it was taken into account that the inhalative absorption rate should be by a factor of 2 higher than the oral absorption as worst-case assumption. Thus, a factor of 0.5 is included.


Corrected starting point = 0.507 mg/kg bw/d x 1/0.288 m³/kg bw/d x 0.5 = 0.88 mg/m³


 

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

Local effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.12 mg/m³
Most sensitive endpoint:
irritation (respiratory tract)
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
10
Dose descriptor:
NOAEC
Value:
3 mg/m³
AF for dose response relationship:
1
Justification:
A NOAEC is used as PoD
AF for differences in duration of exposure:
1
Justification:
There is specific evidence that increasing exposure duration does not increase the incidence or severity of adverse effects of the relevant source substance zinc oxide (5d-14d-90d data). Please refer also to the disseminated registration dossier of zinc oxide.
AF for interspecies differences (allometric scaling):
1
Justification:
not needed for inhalation DNEL as already covered by the correction of the starting point
AF for other interspecies differences:
1
Justification:
not needed as rats considered more sensitive than humans for inhaled inorganic particles.
AF for intraspecies differences:
10
Justification:
default for general population
AF for the quality of the whole database:
1
Justification:
Good quality, as a GLP study similar to OECD Test Guideline is used as PoD.
AF for remaining uncertainties:
1
Justification:
no remaining uncertainties
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:
DNEL (Derived No Effect Level)
Value:
25.35 mg/kg bw/day
Most sensitive endpoint:
genetic toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
1
Dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.507 mg/kg bw/day
Modified dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
25.35 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

The starting point is corrected for a dermal absorption rate of 2 %, which is the generally agreed absorption rate for zinc compounds. The oral absorption is considered 100 % as worst-case.


0.507 mg/kg bw/d x 100 %/2 % = 25.35 mg/kg bw/d

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:
0.507 mg/kg bw/day
Most sensitive endpoint:
genetic toxicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
1
Dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.507 mg/kg bw/day
Modified dose descriptor starting point:
other: Tolerable Upper Intake Level (UL)
Value:
0.507 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

No modification needed as an oral value for humans is used as PoD. 

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

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
low hazard (no threshold derived)

Additional information - General Population

Systemic Long-term DNELs - PoD


A justification for the rationale behind the used PoD is found in the document 'Justification for a thresholded genotoxicity level of (anhydrous) Zinc borate' attached under Section 13.


An alternative way to derive a “safety limit” for anhydrous zinc borate (AZB) is to use the tolerable upper intake level (UL) derived/published by EFSA in 2006.


They derived an UL for zinc to be 25 mg per day per adult person.


Assuming that



  1. only zinc is responsible for adverse effects, at least in our current context of genotoxicity

  2. a person has 70 kg body weight;

  3. average alimentary zinc intake is 12.5 mg per person per day in the EU

  4. and taking into account the zinc concentration in AZB


the resulting “tolerable daily intake” of AZB would be 0.507 mg/kg bw AZB


The calculation is as follows:


zinc concentration in AZB
Zinc borate anhydrous (AZB): M(B6O11Zn2) = 371.64 g/mol.
Zinc concentration in AZB: M(Zn2) = 130.78 g/mol => 35.19%


UL Zinc per kg bw
UL Zinc (EFSA, 2006) = 25 mg/d for adults, corresponding to 357 µg/kg bw/d (assuming 70 kg bw).


Assuming no additional dietary Zn intake:
25 mg Zn/person => 25 mg/35.19% x 100% = 71.04 mg AZB/person = 1.015 mg/kg bw/d (assuming 70 kg bw).


Assuming average (mean) 12.5 mg dietary Zn intake per day per person (EFSA, 2006):


=> “residual tolerable” daily zinc intake


12.5 mg Zn/person => (12.5 mg/35.19%) x 100% = 35.52 mg AZB/person = 0.507 mg/kg bw/d AZB (assuming 70 kg bw)


 


Literature and References


EFSA (2006). Tolerable Upper Intake Levels for vitamins and minerals, Scientific Committee on Food, Scientific Panel on Dietetic Products, Nutrition and Allergies, February 2006, ISBN: 92-9199-014-0