Amorphous condensation products of orthophosphoric acid and sodium carbonate (3-6 : 1)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

No effects were detectable in S. typhimurium tester strains following sublethal pH decrease (read-across).

Link to relevant study records

Reference

Reference 1

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:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

pH changes on bacterial reversion rate was evaluated by adopting 2 modifications of the standard plate incorporation assay

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine locus

Species / strain / cell type:

S. typhimurium TA 97

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium TA 102

Species / strain / cell type:

S. typhimurium TA 1535

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced rat liver S9 was included but the study did not specify if it was used for this test

Test concentrations with justification for top dose:

up to toxic level, different pH’s (ranging from 4 to 9)

Positive controls:

yes

Positive control substance:

sodium azide

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Positive controls:

yes

Positive control substance:

other: daunomycin

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Additional information on results:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.


The reversion properties and specificity of each strain were confirmed by testing MMS, daunomycin, and sodium azide in the standard plate-incorporation assay.

Conclusions:

No effects were detectable in S. typhimurium tester strains following sublethal pH decrease.

Executive summary:

The incubation of S. typhimurium tester strains with different buffer solutions at pH ranging from 5.5 to 9 had no effect on the bacterial reversion rates. The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed.

The same lack of effects was obtained by using the base agar plates at different pH values.

The ineffectiveness of pH decrease was invariably unchanged by the addition of S9 fraction, however no detailed results were reported.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

This read-across is based on the hypothesis that source and target substances have similar properties because of structural similarity and that the target chemical (Amorphous condensation products of orthophosphoric acid and sodium carbonate (3-6 : 1)) hydrolyse to orthophosphoric acid and the sodium dihydrogen phosphate. The sodium dihydrogen phosphate has no identified hazardous properties. The orthophosphoric acid is source substance and is identical to the hydrolysis product of constituent A (metaphosphoric acid) of the target substance.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

pH changes on bacterial reversion rate was evaluated by adopting 2 modifications of the standard plate incorporation assay

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine locus

Species / strain / cell type:

S. typhimurium TA 97

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium TA 102

Species / strain / cell type:

S. typhimurium TA 1535

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced rat liver S9 was included but the study did not specify if it was used for this test

Test concentrations with justification for top dose:

up to toxic level, different pH’s (ranging from 4 to 9)

Positive controls:

yes

Positive control substance:

sodium azide

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Positive controls:

yes

Positive control substance:

other: daunomycin

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.

Positive controls validity:

valid

Additional information on results:

The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed. Values between 5.5 and 9.0 do not exert significant effects.


The reversion properties and specificity of each strain were confirmed by testing MMS, daunomycin, and sodium azide in the standard plate-incorporation assay.

Conclusions:

No effects were detectable in S. typhimurium tester strains following sublethal pH decrease (read-across).

Executive summary:

The incubation of S. typhimurium tester strains with different buffer solutions at pH ranging from 5.5 to 9 had no effect on the bacterial reversion rates. The acidification of incubation mixture to pH 5.0 produced toxic effects on bacteria as the appearance of survivors suggested; at lower pH values, complete bacterial death was observed.

The same lack of effects was obtained by using the base agar plates at different pH values.

The ineffectiveness of pH decrease was invariably unchanged by the addition of S9 fraction, however no detailed results were reported.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)