Potassium tetrahydroborate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Materials and methods are described in detail. The test procedure follows the general procedure for the AMES-Test. Peer-reviewed publication that meets basic scientific principles.

Data source

Reference

Reference Type:

publication

Title:

Absence of mutagenic activity of sodium borate (borax) and boric acid in the Salmonella pre-incubation test.

Author:

Benson W H, Birge W J, Dorough H W

Year:

1984

Bibliographic source:

Environmental Toxicology and Chemistry 3: 209-214.

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Materials and methods are described in detail. The test procedure follows the general procedure for the AMES-Test. Peer-reviewed publication that meets basic scientific principles.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Boric acid

EC Number:

233-139-2

EC Name:

Boric acid

Cas Number:

10043-35-3

Molecular formula:

H3BO3

IUPAC Name:

Boric acid

Test material form:

solid

Specific details on test material used for the study:

Boric acid and Borax were used as test materials.

Method

Target gene:

Histidine

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

with and without

Test concentrations with justification for top dose:

0.01, 0.1, 1, 10, 100 µg/plate for boric acid and borax
In preliminary assays, borax and boric acid showed mutagenic activity at a level of l μglplate; therefore, a range of doses from 0.01 to 100 μg/plate was chosen for study.

Vehicle / solvent:

water

Controls

Untreated negative controls:

yes

Remarks:

spontaneous revertants

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

sodium azide

benzo(a)pyrene

Details on test system and experimental conditions:

The bacterial strains (T A98 and TA 100) were acquired from Dr. B. N. Ames (Biochemistry Department, University of California, Berkeley, CA).

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Table 1. Response of Salmonella test strains to boron and positive control compounds with and without S-9 activation*

Material	Conc. (µg/plate)	TA98 with S-9	TA98 without S-9	TA100 with S-9	TA100 without S-9
Borax	0.01	34±4	30±2	92±11	107±35
Borax	0.1	29±1	30±2	91±6	98±16
Borax	1	34±7	42±4	116±7	81±5
Borax	10	37±8	32±5	121±24	78±12
Borax	100	43±6	31±5	113±8	87±9
Boric acid	0.01	37±3	29±7	104±23	122±14
Boric acid	0.1	35±6	29±3	103±12	112±15
Boric acid	1	44±4	32±11	108±18	126±10
Boric acid	10	43±4	42±1	126±3	127±9
Boric acid	100	40±9	23±7	108±11	127±3
Benzo[a]pyrene	2	142±22	36±8	327±19	125±9
Benzo[a]pyrene	4	322±17	31±4	691±7	111±15
Benzo[a]pyrene	6	540±57	26±3	780±59	110±21
Sodium azide	1	54±6	39±4	101±69	481±7
Sodium azide	5	43±6	35±6	395±21	896±23
Sodium azide	10	36±12	46±13	786±130	986±50
Spontaneous revertants	-	39±1	37±8	111±23	97±11

* Data are expressed as number of revertant colonies per plate per strain (means ± SD).

Applicant's summary and conclusion

Conclusions:

Boric acid and borax can be stated as non-mutagenic under the test conditions.

Executive summary:

The boron compounds failed to produce a mutagenic response in either of the test strains. The revertant colonies produced per plate (23 to 44 and 78 to 127 for TA98 and TA 100, respectively) were not significantly different from the rate of spontaneous revertants for both strains tested.