Neodymium trichloride

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Read-across performed with structurally similar substance (Neodymium Trinitrate)

The test material was considered to be non-mutagenic under the conditions of this test.

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

Study period:

22 August 2012 to 16 October 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Read-across performed with structurally similar substance.

Reason / purpose for cross-reference:

other: read-across target

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

Salmonella typhimurium
TA1537: his C 3076; rfa-; uvrB- (frame shift mutations)
TA98: his D 3052; rfa-; uvrB-; R-factor (frame shift mutations)
TA1535: his G 46; rfa-; uvrB- (base-pair mutations)
TA100: his G 46; rfa-; uvrB-; R-factor (base-pair mutations)

Escherichia coli
WP2 uvrA: trp-; uvrA- (base-pair substitution)

Species / strain / cell type:

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

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9 microsomal fraction from rats induced with phenobarbitone/beta-naphtoflavone

Test concentrations with justification for top dose:

Preliminary toxicity test: 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate (neodymium trinitrate as active ingredient)

Mutation test - experiment 1:
0, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate (neodymium trinitrate as active ingredient)
0, 6, 18, 60, 181, 604, 1811 and 6035 µg/plate (based on the test material (including a water content of 20.7%))

Mutation test - experiment 2:
0, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate (neodymium trinitrate as active ingredient)
0, 6, 18, 60, 181, 604, 1811 and 6035 µg/plate (based on the test material (including a water content of 20.7%))

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: sterile distilled water

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

2 µg/plate for WP2uvrA, 3 µg/plate for TA100, 5 µg/plate for TA1535; without S9-mix

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

80 µg/plate for TA1537; without S9 mix

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-Nitroquinoline-1-oxide

Remarks:

0.2 µg/plate for TA98; without S9 mix

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

1 µg/plate for TA100; 2 µg/plate for TA1535 and TA1537; 10 µg/plate for WP2uvrA; with S9-mix

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

5 µg/plate for TA98; with S9-mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: plate incorporation (mutation test - experiment I) and preincubation method (mutation test - experiment II).

DURATION
- Preincubation period: 20 minutes (mutation test - experiment 2 - pre-incubation method)
- Exposure duration: 48 hours
- Selection time (if incubation with a selection agent): simultaneous with exposure

SELECTION AGENT (mutation assays): trace histidine or tryptophan supplemented

NUMBER OF REPLICATIONS: triplicate

DETERMINATION OF CYTOTOXICITY
- Method: reduction in number of revertant colonies and reduction of bacterial background lawn
- Preliminary toxicity test:
In order to select appropriate dose levels for use in the main test, a preliminary test was carried out to determine the toxicity of the test material. The concentrations tested were 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate (neodymium trinitrate as active ingredient). The test was performed by mixing 0.1 mL of bacterial culture (TA100 or WP2uvrA), 2 mL of molten, trace histidine or tryptophan supplemented, top agar, 0.1 mL of test material formulation and 0.5 mL of S9-mix or phosphate buffer and overlaying onto sterile plates of Vogel-Bonner Minimal agar (30 mL/plate). Ten concentrations of the test material formulation and a vehicle control (sterile distilled water) were tested. In addition, 0.1 mL of the maximum concentration of the test material and 2 mL of molten, trace histidine or tryptophan supplemented, top agar were overlaid onto a sterile nutrient agar plate in order to assess the sterility of the test material. After approximately 48 hours incubation at 37°C the plates were assessed for numbers of revertant colonies using an automated colony counter and examined for effects on the growth of the bacterial background lawn.

Other: S9-mix was used at 10% concentration in plates incubated with metabolic activation.

Evaluation criteria:

There are several criteria for determining a positive result. Any, one, or all of the following can be used to determine the overall result of the study:
1. A dose-related increase in mutant frequency over the dose range tested
2. A reproducible increase at one or more concentrations
3. Biological relevance against in-house historical control ranges
4. Statistical analysis of data as determined by UKEMS (Mahon et al (1989))
5. Fold increase greater than two times the concurrent solvent control for any tester strain (especially if accompanied by an out-of-historical range response.
A test material will be considered non-mutagenic (negative) in the test system if the above criteria are not met.

Although most experiments will give clear positive or negative results, in some instances the data generated will prohibit making a definite judgment about test material activity. Results of this type will be reported as equivocal.

Key result

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A visible reduction in the growth of the bacterial background lawns for all of the tester strains with and without S9-mix at 5000 µg/plate was observed in both experiments.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A visible reduction in the growth of the bacterial background lawns for all of WP2 uvr A with and without S9-mix at 5000 µg/plate was observed in both experiments.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Preliminary toxicity test:
There were substantial decreases in revertant colony frequency noted for TA100 and WP2uvrA (without S9 mix) from 15 and 1500 µg/plate respectively. In the presence of S9 mix, decreases in the revertant colony frequency were observed at 5000 µg/plate only. The test formulation and S9-mix used in this experiment were both shown to be sterile.

Mutation test:
The test material caused a visible reduction in the growth of the bacterial background lawn and/or substantial reductions in revertant colony frequency for all of the tester strains in the presence and absence of S9-mix at 5000 µg/plate in each experiment. These results were not indicative of toxicity sufficiently severe enough to prevent the test material being tested up to the maximum recommended dose level of 5000 µg/plate. A test material precipitate (particulate in appearance) was noted at 5000 µg/plate in each experiment in the absence and presence of S9-mix, this observation did not prevent the scoring of revertant colonies.

No significant increases in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation or exposure method.

All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of the S9-mix and the sensitivity of the bacterial strains.

Conclusions:

The test material was considered to be non-mutagenic under the conditions of this test.

Executive summary:

The genetic toxicity of the test material was investigated in accordance with the standardised guidelines OECD 471, EU Method B.13/14 and OPPTS 870.5100 under GLP conditions.

The test material was tested on the following strains of bacteria: S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A both in the presence and absence of metabolic activation in the form of S9-mix.

The test material caused a visible reduction in the growth of the bacterial background lawn and/or substantial reductions in revertant colony frequency for all of the tester strains in the presence and absence of S9-mix at 5000 µg/plate in each experiment. These results were not indicative of toxicity sufficiently severe enough to prevent the test material being tested up to the maximum recommended dose level of 5000 µg/plate. A test material precipitate (particulate in appearance) was noted at 5000 µg/plate in each experiment in the absence and presence of S9-mix, this observation did not prevent the scoring of revertant colonies. No significant increases in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation or exposure method.

All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of the S9-mix and the sensitivity of the bacterial strains.

The test material was considered to be non-mutagenic under the conditions of this test.

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:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted on read-across material

Justification for type of information:

Read-across performed with structurally similar substance.

Reason / purpose for cross-reference:

read-across source

Key result

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A visible reduction in the growth of the bacterial background lawns for all of the tester strains with and without S9-mix at 5000 µg/plate was observed in both experiments.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

A visible reduction in the growth of the bacterial background lawns for all of the tester strains with and without S9-mix at 5000 µg/plate was observed in both experiments.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Read-across performed with structurally similar substance (Neodymium Trinitrate)

The genetic toxicity of the test material was investigated in accordance with the standardised guidelines OECD 471, EU Method B.13/14 and OPPTS 870.5100 under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

The test material was tested on the following strains of bacteria: S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A both in the presence and absence of metabolic activation in the form of S9-mix.

The test material caused a visible reduction in the growth of the bacterial background lawn and/or substantial reductions in revertant colony frequency for all of the tester strains in the presence and absence of S9-mix at 5000 µg/plate in each experiment. These results were not indicative of toxicity sufficiently severe enough to prevent the test material being tested up to the maximum recommended dose level of 5000 µg/plate. A test material precipitate (particulate in appearance) was noted at 5000 µg/plate in each experiment in the absence and presence of S9-mix, this observation did not prevent the scoring of revertant colonies. No significant increases in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation or exposure method.

All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of the S9-mix and the sensitivity of the bacterial strains.

The test material was considered to be non-mutagenic under the conditions of this test.

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to genetic toxicity.