Sodium dicyanoamide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Method similar to guideline, but test period was 24 h instead of 72 h. No dose range is given.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

No information on dose range is given.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

A commercially available test kit has been used. The manufacturer states that the "Daphtoxkit microbiotest strictly adheres to the protocols for regulatory testing with Daphnias prescribed by international organizations (e.g. ISO standard 6341 and OECD Guideline 202)".

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Version / remarks:

A commercially available test kit has been used. The manufacturer states that the Daphtoxkit microbiotest strictly adheres to the protocols for regulatory testing with Daphnias prescribed by international organizations (e.g. ISO standard 6341 and OECD Guideline 202).

GLP compliance:

not specified

Remarks:

Published data from a scientific study, but not from a testing laboratory.

Specific details on test material used for the study:

- Provider: Merck KGaA (Darmstadt, Germany)
- Purity: > 97 %

Analytical monitoring:

not specified

Vehicle:

not specified

Details on test solutions:

Due to the high water solubility of the test substance (265.0 g/L), it is assumed that the substance may have been dissolved directly in the test medium without the use of a vehicle.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Common name: water flea
- Strain/clone: not specified; ephippia were provided by the manufacturer of the assay kit
- Source: not specified; ephippia were provided by the manufacturer of the assay kit
- Feeding during test: animals were pre-fed
- Food type: not specified
- Age at the start of the experiment: neonates less than 24 hours old

Test type:

other: commercially available Daphtoxkit F (MicroBioTest Incorporation, Gent, Belgium)

Water media type:

freshwater

Remarks:

reconstituted natural freshwater as recommended for the acute toxicity test with Daphnia magna (ISO 6341).

Total exposure duration:

48 h

Remarks on exposure duration:

Scoring was carried out after 24h and 48h incubation.

Post exposure observation period:

not reported

Hardness:

not reported

Test temperature:

20 °C

pH:

not reported

Dissolved oxygen:

not reported

Salinity:

not reported

Conductivity:

not reported

Nominal and measured concentrations:

not reported

Details on test conditions:

The authors claim that the test was carried out according to the instructions of the manufacturer of the commercially available assay kit.
TEST SYSTEM
- Fill volume: 10 mL
- No. of organisms per vessel: 5
- No. of vessels per control (replicates): 5
TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted natural freshwater according to ISO 6341.
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilisation
RANGE-FINDING STUDY: not reported

Reference substance (positive control):

yes

Remarks:

The sensitivity of the organisms to K2Cr207 was checked routinely once a new batch of organisms was obtained. In addition, the test substance was compared to alkali salts of ionic liquid anions where K[(C2F5)3PF]3 showed distinct ecotoxic properties.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 570 mg/L

Nominal / measured:

not specified

Conc. based on:

act. ingr.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 6 400 µmol/L

Nominal / measured:

not specified

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

None described.
Values from 24 h observations are not given.

Results with reference substance (positive control):

- Data on K2Cr2O7 are not provided.
- EC50 of K[(C2F5)3PF]3 was 0.93 µmol/L under these experimental conditions.
- The results with K[(C2F5)3PF]3 as a reference substance are considered valid.

Reported statistics and error estimates:

not described

Validity criteria fulfilled:

yes

Conclusions:

In a 48 h acute immobilisation test using Daphnia magna, the EC50 of the test substance was determined to be 6400 µmol/L or 570 mg/L, respectively.

Executive summary:

The 48 hr acute toxicity of sodium dicyanoamide to Daphnia magna was studied using a commercially available assay kit. The manufacturer states that the assay kit method is in accordance with various guidelines such as OECD 202.

Daphnids were exposed to controls and test chemical at 5 different concentrations for 48 hr. Exact concentrations are not reported. The 48 hour EC50 was 6400 µmol/L or 570 mg/L, respectively.

Based on the results of this study, sodium dicyanamide would be classified as not harmful to Daphnia magna. This toxicity study is regarded as acceptable for an acute toxicity study with freshwater invertebrates besides lacking information on dose range.

Results Synopsis:

Test Organism Age: neonates less than 24 hours old

EC50: 6400 µmol/L or 570 mg/L

Data source

Reference

Reference 1

Reference Type:

publication

Title:

(Eco)toxicity of fluoro-organic and cyano-based ionic liquid anions

Author:

Steudte S, Stepnowski P, Cho C, Thöming J, Stolte S

Year:

2012

Bibliographic source:

Chem. Commun., 2012, 48, 9382–9384

Reference 2

Reference Type:

publication

Title:

The influence of anion species on the toxicity of 1-alkyl-3-methylimidazolium ionic liquids observed in an (eco)toxicological test battery

Author:

Matzke M, Stolte S, Thiele K, Juffernholz T, Arning J, Ranke J, Welz-Biermann U and Jastorff B

Year:

2007

Bibliographic source:

Green Chem., 2007, 9, 1198–1207. DOI: 10.1039/b705795d

Reference 3

Reference Type:

publication

Title:

Predicting the joint algal toxicity of multi-component s-triazine mixtures at low-effect concentrations of individual toxicants

Author:

Faust M, Altenburger R, Backhaus T, Blanck H, Boedeker W, Gramatica P, Hamer V, Scholze M, Vighi M, Grimme LH

Year:

2001

Bibliographic source:

Aquatic Toxicology 56 (2001) 13–32

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

Version / remarks:

According to Matzke et al. (2007) and Faust et al. (2001), the sensitivity of this test system in terms of EC50 values is comparable to the standardised 72 h test (ISO Guideline 8692, Water Quality – Fresh water algal growth inhibition test with Scenedesmus subspicatus and Selenastrum capricornutum, 1989)

Deviations:

yes

Remarks:

algae were exposed to the test substances for one growth cycle (24 h)

GLP compliance:

not specified

Remarks:

Published data from a scientific study, but not from a testing laboratory.

Test material

Test material information

Constituent 1

Reference substance name:

Sodium dicyanoamide

EC Number:

217-703-5

EC Name:

Sodium dicyanoamide

Cas Number:

1934-75-4

Molecular formula:

C2HN3.Na

IUPAC Name:

sodium dicyanamide

Test material form:

solid

Details on test material:

Published data or data from handbook.

Specific details on test material used for the study:

- Provider: Merck KGaA (Darmstadt, Germany)
- Purity: > 97 %

Sampling and analysis

Analytical monitoring:

not specified

Test solutions

Vehicle:

not specified

Details on test solutions:

Due to the high water solubility of the test substance (265.0 g/L), it is assumed that the substance may have been dissolved directly in the test medium without the use of a vehicle.

Test organisms

Test organisms (species):

Chlorella fusca

Details on test organisms:

TEST ORGANISM
- Common name: Scenedesmus vacuolatus, formerly Chlorella fusca var. vacuolata
- Strain: strain 211–15
- Source (laboratory, culture collection): SAG (Culture Collection of algae), Universität Göttingen, Göttingen
- Age of inoculum (at test initiation): autospores (young algal cells at the beginning of the growth cycle)
- Method of cultivation: The stock culture was grown under photo-autotrophical conditions at 28 °C (± 0.5 °C) in an inorganic, sterilized medium (pH 6.4) with saturating white light (intensity of 22 to 33 kilolux) (Lumilux Daylight L 36 W-11 and Lumilux Interna L 36 W-41, Osram, Berlin, Germany). Cells were aerated with 1.5 vol % CO2 and synchronised by using a 14 h light and 10 h darkness cycle.
ACCLIMATION
- Acclimation period: not reported
- Culturing media and conditions (same as test or not): culturing media were aerated with 1.5 vol % CO2. Test media were not aerated but supplemented with 150 µl of NaHCO3 solution in each test tube.
- Any deformed or abnormal cells observed: none described

Study design

Test type:

static

Water media type:

other: inorganic, sterilized medium (pH 6.4)

Total exposure duration:

24 h

Remarks on exposure duration:

According to Matzke et al. (2007) and Faust et al. (2001), the sensitivity of this test system in terms of EC50 values is comparable to the standardised 72 h test.

Post exposure observation period:

not reported

Test conditions

Hardness:

not specified

Test temperature:

28 °C (± 0.5 °C)

pH:

pH 6.4

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

not specified

Details on test conditions:

TEST SYSTEM
- Test vessel: the tests were performed in sterilized glass tubes. The algae were stirred over the whole test period.
- Material, size, headspace, fill volume: 20 mL Pyrex tubes sealed with caps containing a gas tight Teflon membrane
- Aeration: not aerated but supplemented with 150 µl of NaHCO3 solution to give a final concentration of 1.5 mmol/L.
- Initial cells density: 7.50E+04 cells/mL
- Control end cells density: according to the method described by Faust et al. (2001), the cell number increased by an average factor of 12 in untreated controls
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 6
GROWTH MEDIUM
- Standard medium used: not specified; only information given by the authors is: “inorganic, sterilized medium (pH 6.4)”.
TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: culturing media were aerated with 1.5 vol % CO2. Test media were not aerated but supplemented with 150 µl of NaHCO3 solution.
OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: Increase of pH during the test, caused by the assimilation of NO3−, did not exceed 0.2 U according to Faust et al. (2001).
- Photoperiod: 14 h light and 10 h darkness
- Light intensity and quality: saturating white light (intensity of 22 to 33 kilolux) (Lumilux Daylight L 36 W-11 and Lumilux Interna L 36 W-41, Osram, Berlin, Germany).
EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: all cell numbers (stock culture and test) were determined with the Coulter Counter Z2 (Beckmann, Nürnberg, Germany)
TEST CONCENTRATIONS
- Test concentrations: no information on test concentrations given

Reference substance (positive control):

yes

Remarks:

The test substance was compared to four other alkali salts of ionic liquid anions exhibiting different EC50 levels. Amongst these, K[B(CN)4] and K[(C2F5)3PF]3 showed distinct ecotoxicity.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 20 000 µmol/L

Nominal / measured:

not specified

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

ca. 1 780 mg/L

Nominal / measured:

not specified

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): not determined; experimental duration was 24 h
- Any stimulation of growth found in any treatment: not reported
- Effect concentrations exceeding solubility of substance in test medium: not reported

Results with reference substance (positive control):

- The test substance was compared to four other alkali salts of ionic liquid anions exhibiting different EC50 levels. Amongst these, K[(C2F5)3PF]3 showed distinct ecotoxic properties.
- EC50 of K[(C2F5)3PF]3 was 0.40 µmol/L under these experimental conditions.
- The results with K[(C2F5)3PF]3 as a reference substance are considered valid.

Reported statistics and error estimates:

not specified

Any other information on results incl. tables

- Exponential growth in the control (for algal test): not determined; experimental duration was 24 h

- Any stimulation of growth found in any treatment: not reported

- Effect concentrations exceeding solubility of substance in test medium: not reported

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a 24 h algal growth inhibition test using Scenedesmus vacuolatus, the EC50 of the test substance was > 20000 µM.

Executive summary:

In a 24-hour acute toxicity study, the cultures of Scenedesmus vacuolatus, formerly Chlorella fusca var. vacuolata, strain 211-15 (SAG) were exposed to sodium dicyanoamide at nominal concentrations up to 20000 µmol/L under static conditions similar to guideline ISO 8692.  The EC₅₀value based on cell growth was determined to be higher than 20000 µM.  Compound related phytotoxic effects were not described.

This toxicity study is regarded as acceptable for classification besides deviations from guideline regarding exposure period (24 instead of 72 h) and lacking information on dose range. The EC₅₀is > 20000 µM or 1780 mg/L. According to this study, sodium dicyanoamide does not meet criteria for GHS classification.

Results Synopsis

 Test Organism: limnic green algae, Scenedesmus vacuolatus strain 211-15 (SAG)

Test Type: Static

 24 hr EC₅₀> 20000 µM