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Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
6.64 mg/m³
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
12.5
Dose descriptor starting point:
NOAEL
DNEL value:
94.2 mg/kg bw/day
Modified dose descriptor starting point:
NOAEC
DNEL value:
83 mg/m³
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a developmental toxicity study in rats with the structural analogue boric acid (OECD 414; Price, 1996). The estimated NOAEL for boron (MW = 10.8 g/mol) observed in this study is 9.6 mg/kg bw/day which leads to a corrected NOAEL for boron orthophosphate (MW = 106.0 g/mol) of 94.2 mg/kg bw/day.

To correct the interspecies difference between rat and human the NOAEL has to be corrected as follows:

Corrected starting point for the inhalative route for workers:

= NOAEL(oral) * (1/0.38 m³/kg bw/day) * (ABSoral-rat/ABSinh-human) * 6.7 m³ (8h) /10 m³ (8h)

= 94.2 mg/kg bw/day * (1/0.38 m³/kg bw/day) * (1/2) * 0.67 m³ = 83.0 mg/m³

As worst case as recommended in the ECHA Guidance R.8 (2012), it is assumed that oral absorption rate is 50% of that of of inhalation absorption.

(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)

Thus, the corrected starting point for workers was 83.0 mg/m³ for inhalation.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
1
Justification:
Even though the DNEL is derived from a sub-acute study it can be assumed that this is also sufficient for long-term duration because a BMDL05 derived for boric acid (Allen et al., 1996) from several developmental toxicity studies was calculated to be 10.3 mg boron/kg bw/day which is close to the NOAEL derived from the developmental toxicity study (9.6 mg boron/kg bw/day).

Allen et al., 1996; Benchmark Dose Analysis of Developmental Toxicity in Rats Exposed to Boric Acid; Fundamental And Applied Toxicology 32, pp. 194-204
AF for interspecies differences (allometric scaling):
1
Justification:
AF not used for inhalation route.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
5
Justification:
Default value for workers according to ECHA REACH Guidance.
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
acute toxicity
Route of original study:
By inhalation
DNEL related information

Local effects

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

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
188.4 mg/kg bw/day
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
50
Dose descriptor starting point:
NOAEL
DNEL value:
94.2 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
DNEL value:
9 420 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a developmental toxicity study in rats with the structural analogue boric acid (OECD 414; Price, 1996). The estimated NOAEL for boron (MW = 10.8 g/mol) observed in this study is 9.6 mg/kg bw/day which leads to a corrected NOAEL for boron orthophosphate (MW = 106.0 g/mol) of 94.2 mg/kg bw/day.

To correct the interspecies difference between rat and human the NOAEL has to be corrected as follows:

Corrected starting point for the dermal route for workers:

Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal) = 94.2 mg/kg bw/day *(100%/1%) = 18840 mg/kg bw/day. For boric acid and borat compounds a dermal absorption rate of 0.5% is agreed. QSAR calculation (Dermwin) estimate a dermal absorption rate for boron orthophosphate of 1%.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
1
Justification:
Even though the DNEL is derived from a sub-acute study it can be assumed that this is also sufficient for long-term duration because a BMDL05 derived for boric acid (Allen et al., 1996) from several developmental toxicity studies was calculated to be 10.3 mg boron/kg bw/day which is close to the NOAEL derived from the developmental toxicity study (9.6 mg boron/kg bw/day).

Allen et al., 1996; Benchmark Dose Analysis of Developmental Toxicity in Rats Exposed to Boric Acid; Fundamental And Applied Toxicology 32, pp. 194-204
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was a rat.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
5
Justification:
Default value for workers according to ECHA REACH Guidance.
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
hazard unknown but no further hazard information necessary as no exposure expected
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
skin irritation/corrosion

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - workers

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
1.64 mg/m³
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
25
Dose descriptor starting point:
NOAEL
DNEL value:
94.2 mg/kg bw/day
Modified dose descriptor starting point:
NOAEC
DNEL value:
41 mg/m³
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a developmental toxicity study in rats with the structural analogue boric acid (OECD 414; 1996). The estimated NOAEL for boron (MW = 10.8 g/mol) observed in this study is 9.6 mg/kg bw/day which leads to a corrected NOAEL for boron orthophosphate (MW = 106.0 g/mol) of 94.2 mg/kg bw/day.

Corrected starting point for the inhalative route for general population:

= NOAELoral * (1/1.15 m³/kg bw/day (24h)) * (ABSoral-rat / ABSinh-human)

= 94.2 mg/kg bw/day * (1/1.15 m³/kg bw/day) * (1/2) = 41.0 mg/m³

As worst case as recommended in the ECHA Guidance R.8 (2012), it is assumed that oral absorption rate is 50% of that of of inhalation absorption.

(ABSoral-rat = oral absorption in rats, ABSinh-human = inhalation absorption rate in humans)

Thus, the corrected starting point for general population was 41.0 mg/m³ for inhalation.

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
1
Justification:
Even though the DNEL is derived from a sub-acute study it can be assumed that this is also sufficient for long-term duration because a BMDL05 derived for boric acid (Allen et al., 1996) from several developmental toxicity studies was calculated to be 10.3 mg boron/kg bw/day which is close to the NOAEL derived from the developmental toxicity study (9.6 mg boron/kg bw/day).

Allen et al., 1996; Benchmark Dose Analysis of Developmental Toxicity in Rats Exposed to Boric Acid; Fundamental And Applied Toxicology 32, pp. 194-204
AF for interspecies differences (allometric scaling):
1
Justification:
AF not used for inhalation route.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
10
Justification:
Default value for general population according to ECHA REACH Guidance.
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
acute toxicity
Route of original study:
By inhalation
DNEL related information

Local effects

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

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
94.2 mg/kg bw/day
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
100
Dose descriptor starting point:
NOAEL
DNEL value:
94.2 mg/kg bw/day
Modified dose descriptor starting point:
NOAEL
DNEL value:
9 420 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:

The calculation of the DNEL is based on an oral NOAEL observed in a developmental toxicity study in rats with the structural analogue boric acid (OECD 414; Price, 1996). The estimated NOAEL for boron (MW = 10.8 g/mol) observed in this study is 9.6 mg/kg bw/day which leads to a corrected NOAEL for boron orthophosphate (MW = 106.0 g/mol) of 94.2 mg/kg bw/day.

To correct the interspecies difference between rat and human the NOAEL has to be corrected as follows:

Corrected starting point for the dermal route for workers:

Dermal NOAEL = oral NOAEL*ABS(oral)/ABS(dermal) = 94.2 mg/kg bw/day *(100%/1%) = 18840 mg/kg bw/day. For boric acid and borat compounds a dermal absorption rate of 0.5% is agreed. QSAR calculation (Dermwin) estimate a dermal absorption rate for boron orthophosphate of 1%

AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
1
Justification:
Even though the DNEL is derived from a sub-acute study it can be assumed that this is also sufficent for long-term duration because a BMDL05 derived for boric acid (Allen et al., 1996) from several developmental toxicity studies was calculated to be 10.3 mg boron/kg bw/day which is close to the NOAEL derived from the developmental toxicity study (9.6 mg boron/kg bw/day).

Allen et al., 1996; Benchmark Dose Analysis of Developmental Toxicity in Rats Exposed to Boric Acid; Fundamental And Applied Toxicology 32, pp. 194-204
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was a rat.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
10
Justification:
Default value for general population according to ECHA REACH Guidance.
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
hazard unknown but no further hazard information necessary as no exposure expected
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
Most sensitive endpoint:
skin irritation/corrosion

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
0.94 mg/kg bw/day
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
100
Dose descriptor starting point:
NOAEL
DNEL value:
94.2 mg/kg bw/day
AF for dose response relationship:
1
Justification:
The dose descriptor starting point is based on a NOAEL.
AF for differences in duration of exposure:
1
Justification:
Even though the DNEL is derived from a sub-acute study it can be assumed that this is also sufficient for long-term duration because a BMDL05 derived for boric acid (Allen et al., 1996) from several developmental toxicity studies was calculated to be 10.3 mg boron/kg bw/day which is close to the NOAEL derived from the developmental toxicity study (9.6 mg boron/kg bw/day).

Allen et al., 1996; Benchmark Dose Analysis of Developmental Toxicity in Rats Exposed to Boric Acid; Fundamental And Applied Toxicology 32, pp. 194-204
AF for interspecies differences (allometric scaling):
4
Justification:
The experimental animal was a rat.
AF for other interspecies differences:
2.5
Justification:
Default value according to ECHA REACH Guidance.
AF for intraspecies differences:
10
Justification:
Default value for general population according to ECHA REACH Guidance.
AF for the quality of the whole database:
1
Justification:
The DNEL is based on a high-quality study.
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties.
Acute/short term exposure
Hazard assessment conclusion:
low hazard (no threshold derived)
Most sensitive endpoint:
acute toxicity
Route of original study:
Oral
DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - General Population