4-(4-trans-propylcylohexyl)phenol

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

Study period:

16 MAR 2000 - 08 JUN 2000

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)

Version / remarks:

Official Journal of the European Communities Nr. L 383 A, Part C from 29.12.92, Method C.4-E: Closed Bottle Test

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Drainage of the municipal sewage treatment plant of the city of Darmstadt (Südhessische Gas und Wasser AG)
- Preparation of inoculum for exposure: Aeration for 5 days.
- Pretreatment: Filtration through a coarse pleated filter.
- Concentration of sludge: 5 mL/L

Duration of test (contact time):

28 d

Initial conc.:

50 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 20 +/- 1 °C
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2

SAMPLING
- Sampling frequency: weekly

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes

Reference substance:

aniline

Remarks:

2.0 mg/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

28 d

Details on results:

Points of degradation plot (test substance):
3 % degradation after 7 d
2 % degradation after 14 d
4 % degradation after 21 d
4 % degradation after 28 d

Results with reference substance:

Points of degradation plot (reference substance):
74 % degradation after 7 d
87 % degradation after 14 d
90 % degradation after 21 d
100 % degradation after 28 d

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The study was conducted under GLP according to EU Method C.4E on the registered substance itself with marginal deficiencies in documentation in the test report; the available information allows to draw the conclusion that the test was conducted properly without deviation from the guideline. The method is considered reasonable, the reference substance produced the appropriate response and the validity criteria are met. Hence, the results can be considered as reliable to assess the ready biodegradability of the test substance by sludge retrieved from the drainage of a municipal sewage treatment plant. Within the test period of 28 days, a degradation of 4 % was determined for the test substance. Hence, the test substance has to be classified as "Not Readily Biodegradable".

Executive summary:

In a study according to EU Method C.4E under GLP, 50 mg/L of the test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms ( drainage of a municipal sewage treatment plant) and incubated for 28 days under aerobic conditions in the dark at 20 ± 1°C. During this period, the biodegradation of the test substance is determined on the basis of the reduction of dissolved oxygen.

Within the test period of 28 days, a degradation of 4 % was determined for the test substance.

In parallel preparations with the reference substance aniline a degradation of 87 % was achieved within 14 days.

Accordingly, the test substance has to be classified as "Not Readily Biodegradable".

This biodegradation study is classified as acceptable and satisfies the guideline requirement for a biodegradation study (closed bottle test).

Description of key information

Biodegradation in water: screening tests: Not readily biodegradable: 4 % (BOD) in 28 days (EU Method C.4 -E, GLP)

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

In a study according to EU Method C.4E under GLP, 50 mg/L of the test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms (drainage of a municipal sewage treatment plant) and incubated for 28 days under aerobic conditions in the dark at 20 ± 1°C. During this period, the biodegradation of the test substance is determined on the basis of the reduction of dissolved oxygen.

Within the test period of 28 days, a degradation of 4 % was determined for the test substance.

In parallel preparations with the reference substance aniline a degradation of 87 % was achieved within 14 days.

Accordingly, the test substance has to be classified as "Not Readily Biodegradable".

This biodegradation study is classified as acceptable and satisfies the guideline requirement for a biodegradation study (closed bottle test).