Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 06-09-2017 to 05-10-2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
yes
Remarks:
Minor deviations : ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification and river water instead of an effluent/extract/mixture was used as inoculum.
GLP compliance:
yes (incl. certificate)
Remarks:
Inspected on 29-30 August 2017 / Signed on 25 September 2017
Specific details on test material used for the study:
- Storage condition: at ambient temperature in the dark
Oxygen conditions:
aerobic
Inoculum or test system:
natural water
Remarks:
river water
Details on inoculum:
River water was sampled from the Rhine near Heveadorp, The Netherlands (31-08-2017). The nearest plant (Arnhem-Zuid) treating domestic wastewater biologically was 3 km upstream.
The river water was aerated for 7 days before use to reduce the endogenous respiration (van Ginkel and Stroo, 1992). River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating.
Duration of test (contact time):
28 d
Initial conc.:
2 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Test temperature: 22.9 - 23.5 °C
- pH: 8.0 (at day 28 for the control) and 7.9 (at day 28 for the test bottles)
- Bottles were closed and incubated in the dark

- The river water was aerated for 7 days before use to reduce the endogenous respiration (van Ginkel and Stroo, 1992).

TEST SYSTEM
- Use was made of 10 bottles treated with DCM (added and evaporated), 10 bottles containing inoculum and test substance, 10 bottles containing only inoculum, and 6 bottles containing inoculum and sodium acetate.
- Measuring equipment: The dissolved oxygen concentrations were determined electrochemically using an oxygen electrode (WTW) and meter (WTW). The pH was measured using a pH meter. The temperature was measured and recorded with a sensor connected to a data logger.
- Test performed in closed vessels

SAMPLING
- Sampling frequency: Oxygen measurements were performed every seven days

CONTROL AND BLANK SYSTEM
- Inoculum blank: 10 bottles contained only inoculum
- Toxicity control: no toxicity control performed
Reference substance:
acetic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
83
Sampling time:
28 d
Remarks on result:
other: Readily biodegradable and fulfilling the 14-day time window criteria
Results with reference substance:
Sodium acetate was degraded by 85% of its theoretical oxygen demand after 14 days.
Validity criteria fulfilled:
yes
Remarks:
Endogenous respiration of 1.2 mg/L(28 d) ; differences of the replicate values were less than 20% (28d) ; biodegradation percentage of the reference compound at day 14 was 85 %, and oxygen concentrations >0.5 mg/L in all bottles during the test period.
Interpretation of results:
readily biodegradable
Conclusions:
The test item undergoes 83 % biodegradation after 28 days under the test conditions. The 14-day window criteria is also fulfilled. Thus, the test item should be regarded as readily biodegradable according to this test.
Executive summary:

The ready biodegradability of the test item has been determined by the Closed-bottle test according to the OECD Guideline No. 301 D, with GLP compliance.

A nominal concentration of 2.0 mg/L of test substance was introduced into the system.

Concrete of honeycomb cells of the bee by hexane extraction was biodegraded by 83% at day 28 under the test conditions. Over 60% biodegradation was achieved in a period of approximately 6 days immediately following the attainment of 10% biodegradation after 1 day (Figure), therefore fulfilled the 14-day time window (10-day time window for other OECD 301 tests) criterion for ready biodegradable compounds. Sodium acetate was degraded by 85% of its theoretical oxygen demand after 14 days : the activity of the inoculum is thus verified.

According to this test, concrete of honeycomb cells of the bee by hexane extraction should consequently be regarded as readily biodegradable.

Description of key information

OECD guideline 301D, GLP, key study, validity 1:

83 % biodegradation after 28 days, within the 14-days window.

Readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

A biodegradaton study was performed to assess the biodegradation potential of the registered substance, under GLP conditions and according to the OECD Guideline No. 301 D, Closed-bottle test.

A nominal concentration of 2.0 mg/L of test substance was introduced into the system.

Concrete of honeycomb cells of the bee by hexane extraction was biodegraded by 83% at day 28 under the test conditions. Over 60% biodegradation was achieved in a period of approximately 6 days immediately following the attainment of 10% biodegradation after 1 day (Figure), therefore fulfilled the 14-day time window (10-day time window for other OECD 301 tests) criterion for ready biodegradable compounds. Sodium acetate was degraded by 85% of its theoretical oxygen demand after 14 days : the activity of the inoculum is thus verified.

According to this test, concrete of honeycomb cells of the bee by hexane extraction should consequently be regarded as readily biodegradable.