Rhodium trinitrate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

3 September - 22 October 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Conducted according to GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Rhodium trinitrate

EC Number:

233-397-6

EC Name:

Rhodium trinitrate

Cas Number:

10139-58-9

Molecular formula:

HNO3.1/3Rh

IUPAC Name:

rhodium trinitrate

Constituent 2

Reference substance name:

Rhodium (III) nitrate

IUPAC Name:

Rhodium (III) nitrate

Test material form:

other: solution

Details on test material:

- Name of test material (as cited in study report): rhodium (III) nitrate solution
- Substance type: brown/red liquid
- Physical state: liquid
- Analytical purity: no data (assumed 100%)
- Impurities (identity and concentrations): metallic impurities: Ag, Al, As, Au, Ba, Bi, Co, In, Ir, K, Mg, Mn, P, Pb, Pd, Pt, Ru, Sb, Se, Sn, Sr, Te, all ND; Ca, 52 ppm; Cr, 63 ppm; Cu, 8 ppm; Fe, 230 ppm; Na, 675 ppm; Ni, 123 ppm; Si, 28 ppm; Zn, 8 ppm (wrt metal)
- Composition of test material, percentage of components: rhodium, 12.60% w/v; chloride (wrt Rh), 0.16% w/v
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: GB0143
- Expiration date of the lot/batch: 20 May 2017
- Stability under test conditions: no data
- Storage condition of test material: 15-25 deg C protected from light in a tightly closed container

Method

Target gene:

histidine

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

mammalian liver post-mitochondrial fraction (S9) from male Sprague Dawley rats induced with Aroclor 1254

Test concentrations with justification for top dose:

Range-finder and Experiment 1: 5, 16, 50, 160, 500, 1600 and 5000 µg/plate
Experiment 2: 160, 300, 625, 1250, 2500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: purified water
- Justification for choice of solvent/vehicle: well-known solvent/vehicle

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

Strain TA98 -S9 5 µg/plate

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

TA100, TA1535 -S9 2 µg/plate

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

TA1537 -S9 50 µg/plate

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

TA102 -S9 0.2 µg/plate

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

TA98 +S9 10 µg/plate

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

TA100, TA1535, TA1537 +S9 5 µg/plate

Controls 7

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

TA102 +S9 20 µg/plate

Details on test system and experimental conditions:

METHOD OF APPLICATION: Range-finder experiment (with and without S9), Experiment 1 (with and without S9) and Experiment 2 (without S9): in agar (plate incorporation); Experiment 2 (with S9): preincubation

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 3 days

DETERMINATION OF CYTOTOXICITY
- Method: The background lawns of the plates were examined for signs of toxicity. Other evidence of toxicity may have included a marked reduction in revertants compared to the concurrent vehicle controls and/or a reduction in mutagenic response.

Evaluation criteria:

Acceptance Criteria: The assay was considered to be valid if all the following criteria were met:
1. The vehicle control counts fell within the laboratory’s historical control ranges
2. The positive control chemicals induced increases in revertant numbers of ≥1.5 fold (in strain TA102), ≥2 fold (in strains TA98 and TA100) or ≥3 fold (in strains TA1535 and TA1537) the concurrent vehicle control confirming discrimination between different strains, and an active S9 preparation.
Evaluation Criteria: For valid data, the test article was considered to be mutagenic if:
3. A concentration related increase in revertant numbers was ≥1.5-fold (in strain TA102), ≥2-fold (in strains TA98 and TA100) or ≥3-fold (in strains TA1535 and TA1537) the concurrent vehicle control values
4. The positive trend/effects described above were reproducible.
The test article was considered positive in this assay if both of the above criteria were met.
The test article was considered negative in this assay if [n]either of the above criteria were met.

Statistics:

None

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

in Experiments 1 and 2

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 2500 and 5000 µg/plate, with and without S9

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

in Experiments 1 and 2

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate, with S9

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

in Experiments 1 and 2

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 2500 and 5000 µg/plate, without S9

Vehicle controls validity:

valid

Untreated negative controls validity:

not valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

in Experiments 1 and 2

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate, with and without S9, plate incorporation; at 1250, 2500 and 5000 µg/plate, with S9, pre-incubation

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

in Experiments 1 and 2

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate, with and without S9, plate incorporation; at 1250, 2500 and 5000 µg/plate, with S9, pre-incubation

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 6

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

in Experiment 1, with and without S9; in Experiment 2, with S9; also just below +ve threshold in Experiment 2, without S9

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate, with and without S9

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: Range-finder experiment: stock solution, 50 mg rhodium (III) nitrate solution/ml, pH 1.86; Experiments 1 and 2: stock solution, 50 mg rhodium (III) nitrate solution/ml, pH 1.63. "There is no evidence that low pH causes mutations in the Ames test" (Kirkland DJ (2012). Review of the effect of pH on the integrity of in vitro and in vivo genotoxicity assays. Report prepared for The Precious Metals & Rhenium Consortium).
- Precipitation: at 2500 and 5000 µg/plate, pre-incubation (Experiment 2, with S9, TA1535 and TA1537)

RANGE-FINDER EXPERIMENT: strains TA98, TA100 and TA102; evidence of toxicity in the form of a slight thinning of the background bacterial lawn was observed at 5000 µg/plate in all strains in the absence of S9

COMPARISON WITH HISTORICAL CONTROL DATA: mean vehicle control counts were comparable with the laboratory’s historical ranges; mean positive control counts were generally within or higher than the laboratory's historical control ranges (except TA102, experiment 1, without S9: 528 (historical control range 568-1290)

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

In a guideline study, to GLP, rhodium (III) nitrate solution induced mutations in histidine-requiring strains TA98 and TA102 of Salmonella typhimurium when tested up to precipitating concentrations in the absence and presence of a rat liver metabolic activation system (S9), and in strain TA100 in the presence of S9 alone.

Executive summary:

Rhodium trinitrate solution (12.9% rhodium) was tested in a bacterial reverse mutation (Ames) assay, conducted according to OECD Test Guideline 471 and to GLP. The test substance was assayed at test concentrations of up to 5000 µg/plate (it is unclear whether this relates to rhodium nitrate itself or to rhodium nitrate solution), in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of S. typhimurium, both in the absence and in the presence of metabolic activation by an Aroclor 1254-induced rat liver post-mitochondrial fraction (S9). Two experiments were conducted (each in triplicate): initially a plate incorporation protocol was used; the experiment was repeated using a pre-incubation protocol for those strains that were negative in the first experiment.

There was some evidence of toxicity at the highest concentration tested with the plate incorporation protocol and at 1250 -5000 µg/plate with the pre-incubation protocol. Vehicle and positive controls performed as expected. Strain TA98 was positive for mutagenicity in both experiments, with and without S9. Strain TA100 was positive for mutagenicity in both experiments with S9 alone. Strain TA102 was positive in both experiments with S9, in the first experiment without S9 and approaching the threshold for a positive response in the second experiment without S9. Strains TA1535 and TA1537 were negative in both experiments, with and without S9.

Under the conditions of this study rhodium (III) nitrate solution was clearly mutagenic.