N'-(ethylcarbonimidoyl)-N,N-dimethylpropane-1,3-diamine monohydrochloride

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Activated sludge was taken from Totnes Sewage treatment works, Devon, UK. The sludge was kept at room temperature at the laboratory and the pH maintained at 6-8. Seven days prior to exposure, the activated sludge were centrifuged, washed and resuspended in the test medium and the solids concentration determined. This was then diluted and stirred until use.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Test medium as per OECD and EU guidelines.
- Test temperature: 22 +/- 2°C
- pH: The pH of the seeded medium was measured and adjusted as necessary to 7.4 +/- 0.2 prior to use. On Day 0, the pH was measured in a single bottle from the inoculum blanks, reference substance, test substance and toxicity control. The pH in all of the test bottles was measured on day 28.
- Suspended solids concentration: Not specified
- Continuous darkness: Yes (tested in dark glass bottles)
- Apparatus: The measurement of oxygen uptake was conducted using Oxitop respirometers. Each 500 mL bottle contained a magnetic stirrer and the temperature was maintained using an incubator. Carbon dioxide produced was absorbed by a KOH solution placed in the neck of each bottle and the oxygen taken up was measured by a decrease in pressure. Oxygen uptake was recorded automatically every 112 minutes during the 28 day exposure period. These values were corrected for the inoculum blanks and biodegradation was calculated as a percentage of COD for the test substance, and ThOD for the reference substance.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Contained no test or reference substance.
- Abiotic sterile control: Not used.
- Toxicity control: Contained the test substance and reference substance both at 100 mg/L.
- Positive control: Contained the reference substance sodium benzoate at 100 mg/L.
- Other:

STATISTICAL METHODS: No statistical analysis performed

Reference substance:

benzoic acid, sodium salt

Test performance:

All validity criteria of the test were met.

Parameter:

% degradation (O2 consumption)

Value:

< 5

Sampling time:

28 d

Details on results:

The test substance showed < 5% biodegradation after 28 days.

Results with reference substance:

Biodegradation of the reference substance was 70 % on Day 5 which increased to 76% on Day 28 indicating the suitability of the test system.

The pH values on Day 0 ranged from 7.2 to 7.3 and on Day 28 this was determined to be 6.8 to 7.7 when considering all vessels. The temperature was determined to be within the required range over the course of the study.

Biochemical oxygen demand results of the test substance

Bottle contents	BOD
	Test day number
	5	10	15	20	28
Test substance	5.6	5.6	8.4	11	14
	< 5	< 5	< 5	5.6	5.6
	< 5	< 5	< 5	< 5	< 5
Test substance (blank corrected)	< 5	< 5	< 5	< 5	< 5
	< 5	< 5	< 5	< 5	< 5
	< 5	< 5	< 5	< 5	< 5
BOD (g O2/g)	< 0.05	< 0.05	< 0.05	< 0.05	< 0.05
	< 0.05	< 0.05	< 0.05	< 0.05	< 0.05
	< 0.05	< 0.05	< 0.05	< 0.05	< 0.05
% Biodegradation	< 5	< 5	< 5	< 5	< 5
	< 5	< 5	< 5	< 5	< 5
	< 5	< 5	< 5	< 5	< 5
Mean % biodegradation	< 5	< 5	< 5	< 5	< 5

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the conditions of the study, the substance was not deemed to be readily biodegradable as the biodegradation observed was < 5% after a 28 day period.

Description of key information

Under the conditions of the study, the substance was not deemed to be readily biodegradable as the biodegradation observed was < 5% after a 28 day period.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater