Reaction products of boric acid and calcium dihydroxide and lithium hydroxide

Endpoint summary

Description of key information

Read-across to the OECD 405, 431 and 439 studies on dilithium tetraborate is proposed. The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case. Based on the effects noted in the OECD 405 study conducted, Reaction products of boric acid and calcium dihydroxide and lithium hydroxide will be classified as Category 1 : H318: Causes serious eye damage.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

At physiological pH, all lithium/calcium borates dissociate and release boric acid and lithium/calcium ions as a result of relevant transformation pathways. It will be the boric acid component of the substances which will drive the mammalian toxicity endpoints. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity.
The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minute

Value:

93

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: not corrosive

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour

Value:

99

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: not corrosive

Interpretation of results:

GHS criteria not met

Conclusions:

An OECD 431 study was conducted on dilithium tetraborate and found to be non-corrosive. Reaction products of boric acid and calcium dihydroxide and lithium hydroxideis also expected to be non-corrosive.

Executive summary:

An OECD 431 study was conducted on dilithium tetraborate as well as calcium metaborate and found to be non-corrosive. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity as at physiological pH, all the substances dissociate to provide the same common compounds. All substances in the categories: categories: lithium salts of the oxyacids of boron (B); and calcium salts of the oxyacids of boron (B)  do not meet CLP criteria for classification as skin irritants.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

At physiological pH, all lithium/calcium borates dissociate and release boric acid and lithium/calcium ions as a result of relevant transformation pathways. It will be the boric acid component of the substances which will drive the mammalian toxicity endpoints. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity.
The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

Reason / purpose for cross-reference:

read-across source

Irritation / corrosion parameter:

% tissue viability

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, an in vitro skin irritation test was conducted according to OECD 439. Dilithium tetraborate was found to be non-irritant and should not be classified according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) of the United Nations.
Reaction products of boric acid and calcium dihydroxide and lithium hydroxide is also expected to be non-irritant.

Executive summary:

An in vitro skin irritation test was conducted according to OECD 439. Dilithium tetraborate was found to be non-irritant. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity as at physiological pH, all the substances dissociate to provide the same common compounds. 

The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

Reaction products of boric acid and calcium dihydroxide and lithium hydroxide does not meet CLP criteria for classification as skin irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Reaction products of boric acid and calcium dihydroxide and lithium hydroxide has a similar structure to the source substances, dilithium tetraborate and calcium metaborate,

These substances rapidly dissociate in aqueous media yielding the same compound, that is boric acid/borates at physiological pH. As the test item is added directly to the eye, it will be in contact with the aqueous environment of the eye that all members of the categories will dissociate to their relevant components, boric acid and lithium/ calcium ions. It will be the boric acid component of the substance which will drive the eye irritation endpoint.

The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

Read-across to the data obtained on dilithium tetraborate is therefore proposed for the REACH registration of Reaction products of boric acid and calcium dihydroxide and lithium hydroxide negating the need for further animal testing.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Irritation parameter:

cornea opacity score

Basis:

animal: 324

Time point:

24/48/72 h

Score:

0.7

Max. score:

4

Reversibility:

not specified

Irritation parameter:

cornea opacity score

Basis:

animal: 335

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within:

Remarks:

21 days

Irritation parameter:

cornea opacity score

Basis:

animal: 336

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

not specified

Irritation parameter:

iris score

Basis:

animal: 324

Time point:

24/48/72 h

Score:

0.3

Max. score:

2

Reversibility:

not specified

Irritation parameter:

iris score

Basis:

animal: 335

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not specified

Irritation parameter:

iris score

Basis:

animal: 336

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not specified

Irritation parameter:

conjunctivae score

Basis:

animal: 324

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not specified

Irritation parameter:

conjunctivae score

Basis:

animal: 335

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not specified

Irritation parameter:

conjunctivae score

Basis:

animal: 336

Time point:

24/48/72 h

Score:

2.7

Max. score:

3

Reversibility:

not specified

Irritation parameter:

chemosis score

Basis:

animal: 324

Time point:

24/48/72 h

Score:

1.7

Max. score:

4

Reversibility:

not specified

Irritation parameter:

chemosis score

Basis:

animal: 336

Time point:

24/48/72 h

Score:

1.7

Max. score:

4

Reversibility:

not specified

Irritation parameter:

chemosis score

Basis:

animal: 335

Time point:

24/48/72 h

Score:

2.7

Max. score:

4

Reversibility:

not specified

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Based on the not fully recovered effects on the cornea and conjunctivae of one animal after 21 days, dilithium tetraborate should be classified in accordance with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) / Regulation (EC) No 1272/2008 (including all amendments) as Category 1 - causes serious eye damage. Reaction products of boric acid and calcium dihydroxide and lithium hydroxideis also expected to be an eye irritant and shall be classified in an analogous manner.

Executive summary:

An OECD 405 was conducted with dilithim tetraborate. Based on the not fully recovered effects on the cornea and conjunctivae of one animal after 21 days, dilithium tetraborate should be classified in accordance with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) / Regulation (EC) No 1272/2008 (including all amendments) as Category 1 - causes serious eye damage. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity. 

 

The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

 

Reaction products of boric acid and calcium dihydroxide and lithium hydroxide will be classified as Category 1 - causes serious eye damage.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

An OECD 431 and OECD 439 were conducted on dilithium tetraborate and found to be non-corrosive and non-irritant. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in corrosivity/irritancy as at physiological pH, all the substances dissociate to provide the same common compounds.

The target UVCB substance has a higher precursor molar ratio for lithium hydroxide than for calcium hydroxide, and therefore the precautionary principle should be applied and read across from dilithium tetraborate where relevant to consider the worst case.

 

Reaction products of boric acid and calcium dihydroxide and lithium hydroxide therefore  does not meet CLP criteria for classification as skin irritants/corrosion.