1,8-naphthylenediamine

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

Principles of method if other than guideline:

The substance is dissolved in a mineral medium, inoculated with a mixed population of aquatic microorganisms and incubated for 28 days under aerobic conditions in the dark at 20 ± 1 ° C. The biodegradability of the test substance during the time determined by the decrease in the concentration of dissolved oxygen in the test concentrations.

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source: Expiration of a laboratory activated sludge plant is operated with wastewater of southern Wupper Association.
- Treatment given: coarse filtration through fluted filter
- Direct weighing: 2.7 mg/L
- Concentration in the reaction mixture: 5 mL/L
- Preparation / conditioning: Ventilation for 7 days

Duration of test (contact time):

28 d

Initial conc.:

2.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

2.7 mg/L of the test item and 2.0 mg/L of the reference substance was stirred in a closed bottle and inoculated at a constant temperature (20 ± 1 °C) for up 28 days under aerobic conditions in the dark.
Determine the concentration of dissolved oxygen for control purposes; the value should be about 9 mg/L at 20 °C.
Assemble a sufficient number of closed bottles, including inoculum blanks, to allow at least duplicate measurements of oxygen consumption to be made at the desired test intervals, for example, after 0, 7, 14, 21 and 28 days. To ensure being able to identify the 10-day window, more bottles may be required.

Reference substance:

aniline

Remarks:

at least 99.5 %

Parameter:

% degradation (O2 consumption)

Value:

2

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Results with reference substance:

Kinetic of reference substance (% Degradation):
59 after 7 days
75 after 14 days
81 after 21 days
85 after 28 days

Validity criteria fulfilled:

yes

Remarks:

(- Ready biodegradability of reference compound 75 % within 14 days. - In the toxicity control degradation rates > 25 % within 14 days.)

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Within 28 days, a degradation rate of 1 % was determined. 1,8-naphthylenediamine is considered to be "Not Readily Biodegradable". The reference compound aniline showed 75 % degradation after 14 days.

Executive summary:

To test for its biodegradability potential, 1,8-naphthylenediamine was incubated for 28 days in continuously stirred in closed bottle in the dark with an inoculum originally collected form a local, prodominantly municipal wastewater trearment plant.

The incubation temperature was 20 ± 1 °C. Determine the concentration of dissolved oxygen for control purposes; the value should be about 9 mg/L at 20 °C. Assemble a sufficient number of closed bottles, including inoculum blanks, to allow at least duplicate measurements of oxygen consumption to be made at the desired test intervals, for example, after 0, 7, 14, 21 and 28 days. The 28-day degradation was 1 % and for the reference compound the biodegradation was 85 %. In conclusion the substance is not readily biodegradable.

Description of key information

Within 28 days, a degradation rate of 1 % was determined. The test item is considered to be "Not Readily Biodegradable". The reference compound aniline showed 75 % degradation after 14 days.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed