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

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:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Sublethal pH Decrease May Cause Genetic Damage to Eukaryotic Cell: A Study on Sea U rc h ins and Salmonella typhimurium

Author:

Maria Cipollaro, Giuliana Corsale, Agostino Esposito, Enrica Ragucci, Norma Staiano, Giovan Giacomo Giordano, and Giovanni Pagano

Year:

1986

Bibliographic source:

Teratogenesis, Carcinogenesis, and Mutagenesis 6:275-287 (1986)

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

Orthophosphoric acid

EC Number:

231-633-2

EC Name:

Orthophosphoric acid

Cas Number:

7664-38-2

Molecular formula:

H3O4P

IUPAC Name:

phosphoric acid

Method

Target gene:

Histidine locus

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 97

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 100

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 102

Species / strain 5

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)

Controls

Controls 1

Positive controls:

yes

Positive control substance:

sodium azide

Controls 2

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Controls 3

Positive controls:

yes

Positive control substance:

other: daunomycin

Results and discussion

Test results

Test results 1

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

Test results 2

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

Test results 3

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

Test results 4

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

Test results 5

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.

Applicant's summary and conclusion

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.