Zinc cyanide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

For that endpoint, many reliable studies were available.

Two studies were performed on the registered substance (ZnCN):

- one study to assess the chromosomal aberration on Chinese Hamster Lung (CHL/IU). This study was performed according to the OECD Guideline 473 (In Vitro Mammalian Chromosomal Aberration)

- one study to assess reverse mutation on Salmonella typhimurium. This study was performed according to the OECD Guideline 471 (Bacterial Reverse Mutation Assay).

Two studies were performed on similar substances, KCN (potassium cyanide) and ZnCl (zinc chloride) to assess the gene mutations on mammalian cells in vitro. The study on ZnCl met generally accepted scientific principles, acceptable for assessment. The study on KCN was performed according to the guideline EU Method B17.

Under the experimental conditions, the registered substance Zinc cyanide has a frequency of cells with chromosome aberrations below 5%. Therefore, Zinc cyanide did not show a potential to induce chromosomal aberrations.

Moreover, Zinc cyanide was considered not have reverse mutagenic potential of bacterial strain.

Besides, based on the read across on the similar substances KCN (potassium cyanide) and ZnCl (zinc chloride), Zinc cyanide is expected to be not mutagenic in mammalian cells.

The validity criteria were successful and the study was therefore regarded as acceptable for that endpoint.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosomal Aberration Test)

Deviations:

not specified

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

Chinese hamster lung (CHL/IU)

Metabolic activation:

with and without

Metabolic activation system:

After pre-incubation, each plate was divided into three groups: short time treatments with or without metabolic activation and the continuous treatment without metabolic activation.

Test concentrations with justification for top dose:

The high dose of the test substance was 2,000 µg/mL, which was the limit dose recommended in the guideline. The high dose was sequentially diluted to produce lower dose levels (1,000, 500, 250, 125, 62.5, 31.3, 15.6, 7.81 µg/mL). The negative control group was set.

Vehicle / solvent:

Normal saline batch No KAH5112 1B, KAH5056 2B

Untreated negative controls:

yes

Remarks:

Normal saline. The vehicle of the test substance, normal saline, was used as the negative control.

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

mitomycin C

Details on test system and experimental conditions:

In the short time treatments with and without metabolc activation, cells were treated with the test substance for 6 hours.In the continuous treatment without metabolic activation, cells were treated with the test substance for 24 hours.

Evaluation criteria:

Evaluation of the validity of the study resutl was conducted based on the following criteria. (1) The frequency of cells with chromosome aberrations in the negative and positive control groups in below 5% and above 10%, respectively. (2) The dose levels which have more than 300 metaphases per dose are above three. (3) the cultures do not show any evidence of contamination.

Statistics:

statistical analysis on the frequency of cells with chromosome abberations was performed using SAS prgram (Version 9.3, SAS Institute Inc., U.S.A.). For the data of cell aberration, Fisher's exact test was used for comparison of the negative control group to the test substance groups and the positive control group (p < 0.05).

Species / strain:

Chinese hamster lung (CHL/IU)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

The frequency of cells with chromosomal aberrations was less than 5% in the short time treatment with and without metabolic activation and the continuous treatment without metabolic activation and statistical analysis on the frequency of cells with chromosome aberrations change was not found. The positive control group, the frequency of cells with structural chromosomal aberrations was at more than 10% increased compared to that in the negative control group.

Conclusions:

In conclusion, the test substance, the frequency of cells with chromosome aberrations was below 5%, zinc cyanide, did not show a potential to induce chromosomal aberrations in Chinese Hamster Lung (CHL/IU) cell under the conditions of this study.

Executive summary:

For that endpoint, one reliable study to assess the chromosomal aberration on the registered substance on Chinese Hamster Lung (CHL/IU) was available. The study was performed according to the OECD Guideline 473 (In Vitro Mammalian Chromosomal Aberration).

Under the experimental conditions, the registered substance " Zinc cyanide batch n°10185145" has a frequency of cells with chromosome aberrations below 5%. Therefore, Zinc cyanide did not show a potential to induce chromosomal aberrations.

The validity criteria were successful and the study was therefore regarded as acceptable for that endpoint.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Test concentrations with justification for top dose:

The highest dose of the test substance was selected at 5,000 µg/plate. The highest dose was sequentially diluted by a geometric ratio of 4 to produce total 7 dose levels(1.22, 4.88, 19.5, 78.1, 312.5, 1,250 and 5,000 µg/plate).

Vehicle / solvent:

Dimethyl sulfoxide (DMSO)

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Details on test system and experimental conditions:

PRE-INCUBATION: Stock cultures were thawed and the bacterial suspensions were inoculated in 2.5 % Nutrient broth by shaking at approximately 37 °C. Following pre-incubation, the optical density of each strains was measured by ELISA reader(600 nm, EPOCH, BioTek, USA) and the number of cells calculated. Also, number of viable cells of more than 1 x 109 cells/mL was used. As a result, viable cells were confirmation for 1.45 ~ 11.54 x 109 cells/mL of Salmonella typhimurium strains, 1.23 ~ 4.75 x 109 cells/mL of Escherichia coli strain.

TREATMENT METHOD:
- In the presence of metabolic activation, 0.1 mL of each test substance solution, the negative and positive controls and pre-incubated bacterial suspensions were placed in tube. And 0.5 mL of S9 mix was added. And then, 2 mL of molten top agar containing trace histidine or tryptophan was added to each tube. These mixtures were overlaid onto sterile minimal glucose agar plate.
-In the absence of metabolic activation, 0.5 mL of 0.2 M sodium phosphate buffer(pH 7.4) instead of S9 mix was added, the following step was identical with the above.

Evaluation criteria:

The results were considered to be positive when the following conditions are met.
The number of revertant colonies in any strains at one or more doses were increased at least two timeswhen compared to the negative control value. It was increased as dose dependency or reproducibility. Equivocal results should be clarified by further testing preferably using a modification of experimental conditions.

Species / strain:

other: Salmonella typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2uvrA(pKM101)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

PRELIMINARY STUDY: As a result of preliminary study, in the presence and absence of metabolic activation, the precipitation of test substance was observed at 1,250 and 5,000 µg/plate dose levels of all strains. Also, the growth inhibition was observed at 312.5 ~ 5,000 µg/plate of TA98 and TA1537 strains, at 1,250 and 5,000 µg/plate dose levels of TA100, TA1535 and WP2uvrA(pKM101) in the presence of metabolic activation. And the growth inhibition was observed at 78.1 ~ 5,000 µg/plate of TA98 strain, at 312.5 ~ 5,000 µg/plate of TA100 strain and at 1,250 and 5,000
µg/plate of TA1535, TA1537 and WP2uvrA(pKM101) in absence of metabolic activation.

MAIN STUDY:
- Reverse mutation colonies of the test substance: In the presence and absence of metabolic activation systems, a dose-dependent increase in
the number of reverse mutation colonies was not observed when compared to the negative control group.
- Growth inhibition and precipitation of the test substance: As a result, the precipitation of the test substance was observed at 625 and 1,250 µg/plate
of TA100, TA1535 and WP2uvrA (pKM101) strains in presence of metabolic activation. Also, the precipitation of test substance was not observed at all dose levels of all strains and the precipitation of the test substance were not observed in the other strains. Also, the growth inhibition of test substance was observed at 1,250 µg/plate of TA100 and TA1535 strains, at 312.5 µg/plate of TA98 and TA1537 strains and at 625 and 1,250
µg/plate of WP2uvrA (pKM101).

Conclusions:

This study was satisfaction to acceptability of test. And, in the presence and absence of metabolic activation systems, a dose-dependent increase in the number of reverse mutation colonies was not observed all strains. Also, this result was not satisfaction to evaluation criteria of positive result.
In conclusion, the test substance, Zinc cyanide was considered not have reverse mutagenic potential of bacterial strain under the present study conditions.

Executive summary:

For that endpoint, one reliable study to assess genetic toxicity in vitro on the registered substance on Salmonella typhimurium and Escherichia coli was available. The study was performed according to the OECD Guideline 471 (Bacterial Reverse Mutation Assay).

Under the experimental conditions, the registered substance " Zinc cyanide batch n°10185145" was considered not have reverse mutagenic potential of bacterial strain.

The validity criteria were successful and the study was therefore regarded as acceptable for that endpoint.

Reference 3

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

yes

Type of assay:

in vitro mammalian cell gene mutation test using the Hprt and xprt genes

Target gene:

HGPRT

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Metabolic activation system:

Arochlor 1254 rat liver microsomes

Test concentrations with justification for top dose:

The dose-levels for the main study were 400, 800, 1000, 2000 and 3000 μg/ml without S9 mix and 1000, 2000, 3000, 4000, 6000, 8000 and 10 000 μg/ml with S9 mix.

Vehicle / solvent:

water

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9,10-dimethylbenzanthracene

ethylmethanesulphonate

Details on test system and experimental conditions:

Cells and tissue culture media:
V79 cells are maintained in Dulbecco's modified Eagle-medium supplemented with 10% fetal calf serum, penicillin and streptomycin, called DMEM-FCS. Two independent experiments each with and without S9 mix were carried out.
Cultures are incubated at 37oC in a humidified atmosphere (90%) containing 10% CO2. Exposure to the test compound in the presence of S9 mix is performed in Dulbecco’s phosphate buffered saline (PBS) which additionally contains 20 mM HEPES, pH 7.4 (PBS-HEPES).
Preparation of the Aroclor 1254 S9 mix was according to standard protocol (Maron and Ames, 1983).
Cytotoxicity Experiment.: On the day following subculturing of V79 cells the cells are exposed to a wide range of concentrations of concentrations of the test compound. In the absence of S9 mix, the cells are exposed in DMEM-FCS to the test compound for 24 hours. In the experiments with S9 mix, the medium is replaced by 18 ml S9 mix and the exposure limited to 2 hours. After removal of the test compound and washing of the plates with PBS, the cells are trypsinized and the relative plating efficiency. Three replicate plates are used with a known number of cells. After about 8 days, the cells are fixed and stained with methylene blue in ethanol. The colonies are then counted.
A concentration of the test compound which produces a low level of survival (10-60%) is used as the highest concentration.
Mutagenicity experiments:
On the day following plating, the cells are exposed to the test compound. After removal of the test compound after the specified time, and washing of the cells with PBS, the cells are trypsinized and a relative plating efficiency (PE1) is determined for each dose. The remaining cells are replated and the culture incubation continued until day 8 with normal DMEM-FCS with one subcultivation on day 5. After 8-12 days, the cells are harvested by trypsinization and replated at 1.0E6 per 150 nm in DMEM-FCS in medium without 6-thioguanine for the estimation of plating efficiencies (PE2). The plates are fixed and stained after 8-12 days.
The concentrations of positive controls EMS were 600 and 700 microgram/ml and DMBA were 20 and 20 microgram/ml.

Evaluation criteria:

For the compound to be considered negative, solvent and positive controls show results within the norm and if the test compound does not increase the mutation frequency 2-fold above the mean of the solvent controls under any condition, or if the mutation frequency is always lower than 20.0E-6, and if at least 1.0E6 cells per condition have been evaluated.
For the compound to be considered positive, the dose-dependent increase of the mutation frequency in both independent experiments to at least 2-fold times the solvent control and at least 20.0E-6 both in the presence and/or absence of S9 mix.

Statistics:

not applicable

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

The mutation frequencies of the solvent controls ranged from 7.3 to 15.0E-6 clonable cells, and were within the range of historical controls (1 to 44 mutants per 1.0E6 cells). The mutation frequencies of the KCN treated cells (without S9) ranged from 0.4 to 14.9E-6 clonable cells, and were within the range of historical controls (1 to 44 mutants per 1.0E6 cells). In the presence of S9 mix, the mutation frequencies of the KCN treated cells ranged from 3.0 to 24.4E-6 clonable cells, and were also within the range of historical controls (1 to 44 mutants per 1.0E6 cells). The mutation frequency of 24.4E-6 is probably related to extremely high cytotoxicity (plating efficiency 0.00%).

Positive control EMS in the direct test, and DMBA in the activated test, caused a pronounced increase in the mutation frequencies, ranging from 745 to 1495E-6 clonable cells, and 333 to 539E-6 cells, respectively.

Conclusions:

Potassium cyanide, tested up to a dose-related high cytotoxicity in the absence and presence of metabolic activation, was negative (non-mutagenic) at the HGPRT locus in the in-vitro mammalian gene mutation assay using V79 cells.

Reference 4

Endpoint:

in vitro gene mutation study in mammalian cells

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

Principles of method if other than guideline:

Cells deficient in thymidine kinase (TK) due to the mutation TK+/- to TK-/- are resistant to the cytotoxic effects of trifluorothymidine (TFT). Thymidine kinase proficient cells (TK+/-) are sensitive to TFT, which causes the inhibition of cellular metabolism and halts further cell division. Thus mutant cells are able to proliferate in the presence of TFT, whereas normal cells, which contain thymidine kinase, are not able to proliferate.

GLP compliance:

not specified

Type of assay:

in vitro mammalian cell gene mutation tests using the thymidine kinase gene

Target gene:

Thymidine kinase locus/TK +/-

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

- Type and identity of media: RPMI 1640 medium
- Properly maintained: Yes
- Periodically checked for Mycoplasma contamination: Yes
- Periodically checked for karyotype stability: No data
- Periodically "cleansed" against high spontaneous background: Yes

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Metabolic activation system:

NA

Test concentrations with justification for top dose:

1.21-12.13 µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Normal saline (1 %)
- Justification for choice of solvent/vehicle: Not reported

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

METHOD OF APPLICATION: In medium


DURATION
- Preincubation period: Not reported
- Exposure duration: 3 h
- Expression time (cells in growth medium): 48 h
- Selection time (if incubation with a selection agent): 7 d (at 37 °C in 5 % C02-95 % humidified air)



SELECTION AGENT (mutation assays): 5-trifluorothymidine (TFT) - 4 μg/mL


NUMBER OF REPLICATIONS: Duplicate cell culture for test material treatment while triplicate plates were prepared for both survival and mutation frequency determinations for each of the 2 replicate cultures


NUMBER OF CELLS EVALUATED: Cells densities were 30000/mL (1 x 100,000/plate) for mutant selection and 15/mL (500/plate) for viability detrmination


DETERMINATION OF CYTOTOXICITY
- Method: Cell survival for each culture was the product of growth in suspension culture and cloning efficiency in soft-agar medium, each relative to solvent controls

OTHER: Cell culture contained 6 x 100,000 cells each in 10 mL test medium
Light exposure was minimal during treatment of cells.
Test conducted at 37 °C
For the recovery and mutant expression, all cells were maintained at 37 °C for 48 h in log phase growth after treatment with test material

Evaluation criteria:

Colonies growing in the presence of triflurothymidine (TFT resistant) or its absence (viable count colonies) were counted. TFT Resistant colonies which were equivalent in size to colonies growing in the solvent control viable count plates ie., large, were scored as mutants.

Statistics:

Not reported

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Conclusions:

The test material was found to be non-mutagenic under the test conditions.

Executive summary:

A study was conducted to assess the potential mutagenicity of test material in the mouse lymphoma thymidine kinase locus using the cell line L5178Y.

The mouse lymphoma cells (TK+/-) were treated with test material at 1.21-12.13 µg/mL for 3 h. 48 h after treatment, cells were treated with 4 µg/mL trifluorothymidine (TFT) for 7 d. Colonies growing in the presence of triflurothymidine (TFT resistant) or its absence (viable count colonies) were counted. TFT resistant colonies which were equivalent in size to colonies growing in the solvent control viable count plates i.e., large, were scored as mutants.

The test material was found to be non-mutagenic under the test conditions.

Reference 5

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

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

Remarks:

zinc chloride and potassium cyanide

Adequacy of study:

weight of evidence

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The read-across between the source substances ZnCl and KCN and the target substance ZnCN can be performed because they share common functional groups (Zn and CN).

2. SOURCE AND TARGET CHEMICAL(S)
The source substances are ZnCl and KCN and the target substance is ZnCN.

3. ANALOGUE APPROACH JUSTIFICATION
Based on the close analogy between the source and the target substances, it can be assumed that the read-across approach is relevant.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

not specified

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Conclusions:

The source studies on KCN and ZnCl did not show any gene mutation in mammalian cells when tested in vitro.
Based on the read across approach on ZnCN, it can be concluded that ZnCN is not expected to induce gene mutation in mammalian cells as well.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

For that endpoint, one reliable study to assess in vivo genotoxicity on the registered substance on mammalian erythrocyte was available. The study was performed according to the OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test).

Under the experimental conditions, the registered substance " Zinc cyanide batch n°10185145" does not increase MNPCE at any doses tested compared to the negative control group. In addition, no statistical significance was observed in the value for the ratio of PCE to total erythrocytes between the test substance-dosed group and negative control group. Therefore, the registered substance " Zinc cyanide batch n°10185145" was determined not to indice an increased frequency micronuclei in the bone marrow cells of male ICR mice under these experimental conditions.

The validity criteria were successful and the study was therefore regarded as acceptable for that endpoint.

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

mammalian erythrocyte micronucleus test

Species:

mouse

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

Animal number: Dose range-finding test: male and female, 18 animals / Main test: male, 33 animals
Age: 6 weeks / 7 weeks old
Quarantine and acclimatation: all animals examined for quarantine at the time of receipt and be acclimatized to housing condition. The healthy animals selected and used for the study based on general health conditions.
Identification : the animal labeled on tail with permanent marker pen and identification cards attached to each cage for an individual discrimination
Group assignment: after acclimation periods, animals weighted and randomly assigned according to body weight average and standard deviation.
ENVIRONMENTAL CONDITIONS
Temperature: 22 ± 3°C
Relative humidity: 50 ± 20 %
Air exchange: 10-20 times/h
Light cycle: light 12h / dark 12h
Illumination: 150-300 Lux
Animal per cage: more than 3 animals

Route of administration:

oral: gavage

Duration of treatment / exposure:

The test substance was administrated twice to starved animals for 3-4 hours by oral gavage (sonde), and positive control was administrated with a single intraperitoneal injection at the same time as final (2nd) administration day.

Frequency of treatment:

It was injected twice (24 hour interval). However, positive control was administered one time on the last administration day.

No. of animals per sex per dose:

Dose range-finding test 1: 3
Dose range-finding test 2: 3
Dose range-finding test 3: 3
Main test: 5

Positive control(s):

Name of the substance: Cyclophosphamide monohydrate (CPA)
Supplier: Sigma-Aldrich, Inc.
Purity: 99.9%

Tissues and cell types examined:

Bone marrow cells

Evaluation criteria:

- Discrimination of polychromatic Erythrocytes: polychromatic erythrocytes are determined by appearence of orange-fluorescent light without nuclei.
- Discrimination of nonchromatic erythrocytes: nonchromatic erythrocytes are determined by appearence of only their black shadows without fluorescent light.
- Criteria of micronucleus: SIZE: from the smallest distinguishable one to the one as large as a half the diameter of erythrocytes. SHAPE: mainly round and includes the form of donut shape, half moon shape and so on. COLOR: same color with near cell nucleus; green fluorescent in acridine orange.

Statistics:

The following statistic analyses were done using a SPSS program (ver. 19.). The result of the statistical evaluation was regarded significantly when the P value was less than 0.5.

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

Under the experimental conditions, the results showed that there was no increase of MNPCE at any dose of the test substance compared to the negative control group, and also statistical significance was not observed. In addition, no statistical significance was observed in the value for the ratio of PCE to total erythrocytes between the test substance-dosed group and negative control group.
Therefore, the test substance, Zinc cyanide, was determined not to indice an increased frequency micronuclei in the bone marrow cells of male ICR mice under the present experimental condition.

Executive summary:

For that endpoint, one reliable study to assess in vivo genotoxicity on the registered substance on mammalian erythrocyte was available. The study was performed according to the OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test).

Under the experimental conditions, the registered substance " Zinc cyanide batch n°10185145" does not increase MNPCE at any doses tested compared to the negative control group. In addition, no statistical significance was observed in the value for the ratio of PCE to total erythrocytes between the test substance-dosed group and negative control group. Therefore, the registered substance " Zinc cyanide batch n°10185145" was determined not to induce an increased frequency micronuclei in the bone marrow cells of male ICR mice under these experimental conditions.

The validity criteria were successful and the study was therefore regarded as acceptable for that endpoint.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)