Sodium dicyanoamide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Data waiving:

study technically not feasible

Justification for data waiving:

the study does not need to be conducted because the substance is inorganic

Reason / purpose for cross-reference:

data waiving: supporting information

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not specified

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Reason / purpose for cross-reference:

data waiving: supporting information

Qualifier:

no guideline followed

Version / remarks:

Medium according to OECD 301 was used.

Principles of method if other than guideline:

Alkaline cations were tested in different growth media using ion chromatography for the examination of their primary biodegradability.

GLP compliance:

no

Specific details on test material used for the study:

The experiments in this study refer to the anion of dicyanamide salts, in this case from potassium dicyanamide.

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: bacteria from an industrial waste water treatment plant (Merck KGaA factory, Darmstadt, Germany) were not cultivated but received from the plant directly
- T=20 °C, OECD test guideline 301 medium, 1 % bacteria suspension, C/N ratio 5

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 100 µmol/L

Based on:

act. ingr.

Remarks:

ca. 9 mg/l

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

- The bacteria from an industrial waste water treatment plant (Merck KGaA factory, Darmstadt, Germany) were not cultivated but received from the plant directly and used within a limited time period of one week. It was taken there, transported in a 10-L container overnight and aerated with oxygen in our lab before use.
- OECD guideline 301 medium (OECD 1992)
- samples were taken at day 0, 14 and 28.

Preliminary study:

not conducted

Test performance:

not specified

Key result

Parameter:

% degradation (test mat. analysis)

Value:

>= 0

Sampling time:

28 d

Details on results:

- industrial sewage sludge bacteria were not able to use the anions as carbon or nitrogen sources.
- There was no decrease in the relative concentration of N(CN)2−.

Please see the attached figure which has been taken from the publication.

Validity criteria fulfilled:

not applicable

Interpretation of results:

not readily biodegradable

Conclusions:

The dicyanamide anion was found to be not readily biodegradable.

Executive summary:

Neumann et al. (2014) have examined the biodegradation of cyano-based ionic liquid anions, amongst these the N(CN)₂⁻anion, under different conditions. In an assay using industrial activated sludge, the relative concentration of the N(CN)₂⁻anion showed no significant decrease over a time period of 28 days. In consequence, anions like the dicyanamide anion are stated not to be readily biodegradable.

Description of key information

As an inorganic substance, sodium dicyanamide does not need to be tested for ready biodegradability according to REACh.

However, a publication exists which deals with the biodegradation of cyano-based ionic liquid anions, amongst these the N(CN)₂⁻anion, where practically no biodegradation of the dicyanamide anion was observed when incubated in industrial activated sludge for 28 days (Neumann et al. 2014).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed