Reaction products of boric acid and lithium hydroxide

Endpoint summary

Description of key information

Read-across to the OECD 405, 431 and 439 studies on dilithium tetraborate is proposed. Based on the effects noted in the OECD 405 study conducted, all members of the category 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 based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

At physiological pH, all lithium borates dissociate and release boric acid and lithium ions as a result of relevant transformation pathways. It will 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. In order to minimise animal testing, only one substance in the category was tested, dilithium tetraborate. For all other substances in the category, read-across is proposed.

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. The UVCB-Reaction products of boric acid and lithium hydroxide is also expected to be non-corrosive.

Executive summary:

An OECD 431 study was conducted on dilithium tetraborate 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 category do not meet CLP criteria for classification as skin irritants.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

At physiological pH, all lithium borates dissociate and release boric acid and lithium ions as a result of relevant transformation pathways. It will 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 skin irritation. In order to minimise animal testing, only one substance in the category was tested, dilithium tetraborate. For all other substances in the category, read-across is proposed.

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. The UVCB-Reaction products of boric acid 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. All substances in the category do not meet CLP criteria for classification as skin irritants.

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 based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

The UVCB-Reaction products of boric acid and lithium hydroxide and dilithium tetraborate are structural very similar. Variations in the structure (trigonal vs tetrahedral) between the substances are not expected to lead to any changes in eye irritation. In order to minimise animal testing, only one substance in the category was tested, dilithium tetraborate. For all other substances in the category, read-across is proposed.

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. The UVCB-Reaction products of boric acid and lithium hydroxide is 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. All substances in the category 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. All substances in the category do not meet CLP criteria for classification as skin irritants/corrosion.

An OECD 405 was conducted with dilithium 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 as at physiological pH as all the substances dissociate to provide the same common compounds. All substances in the category will be classified as Category 1 - causes serious eye damage.