Benzoic acid, 4-hydroxy-, 1,1'-(1,4-phenylene) ester

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998-04-21 to 1998-06-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD study under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

92/69/EWG, C.4-E (Geschl. Flasch.)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Hydrochinone-bis-p-hydroxybenzoate

IUPAC Name:

Hydrochinone-bis-p-hydroxybenzoate

Details on test material:

- Name of test material (as cited in study report): Hydrochinone-bis-p-hydroxybenzoate (OH-Dreikerner)
- Physical state: solid
- Storage condition of test material: in darkness at room temperature

Study design

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): sewage plant Groß-Zimmern, Germany
- Method of cultivation: The activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. Two washing steps with tap water followed.
- Storage conditions: Aliquots of washed sludge suspension, corresponding to 4 g dry material per litre were mixed with test water and then aerated untiol use.
- Storage length: not given in the report
- Water filtered: yes
- Type and size of filter used, if any: cotton wool

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

2 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: KH2PO4 8.5 mg/l, K2HPO4 21.75 mg/l, Na2HPO4.2H2O 33.4 mg/l, NH4Cl 0.5 mg/l, MgSo4.7H2o 22.5 mg/l, CaCl2 27.5 mg/l, FeCl3.6H2O 0.25 mg/l, 36.4 mg/l CaCl2.2H2O
- Test temperature: 22 °C
- pH: 7.3 - 7.4
- Oxygen concentration of the test water: 8.75-8.90 mg O2/L
- pH adjusted: not given in the report

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes
- Procedure control: yes (Aniline)

TEST SYSTEM
- Culturing apparatus: Karlsruher flasks of 250 mL volume with glass stoppers
- Number of culture flasks/concentration: 16 bottles containing the test substance, 16 bottles with the reference substance, 16 bottles containing only inoculum and 8 bottles containing both the test and the reference substance
- Measuring equipment: oxygen electrode and pH-meter ECM Multi

SAMPLING
- Sampling frequency: Duplicate on days 0, 2, 5, 7, 12, 14, 21, 28

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

12.1

Sampling time:

28 d

Details on results:

Points of degradation plot (test substance):
-4.7 % degradation after 2 d
-1.3 % degradation after 5 d
-0.5 % degradation after 7 d
12.6 % degradation after 12 d
12.1 % degradation after 14 d
11.6 % degradation after 21 d
12.1 % degradation after 28 d

BOD5 / COD results

Results with reference substance:

Points of degradation plot (reference substance):
0.6 % degradation after 2 d
50.2 % degradation after 5 d
56.9 % degradation after 7 d
62.9 % degradation after 12 d
66.2 % degradation after 14 d
78.9 % degradation after 21 d
77.6 % degradation after 28 d

Any other information on results incl. tables

Hydroquinone-bis-p-hydroxybenzoate (OH-Dreikerner) is not redily biodegradable. The reference compound Aniline was sufficiently degraded to in the mean 66.2% afer 14 days and to 77.6% after 28 days, thus confirming the suitability of the used activated suludge inoculum. The biodegradation in the toxicity control containing both, the test substance and the reference compound Aniline showed a similar course over the 28 days of exposure as the procedure control containing the reference compound Aniline only.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Hydroquinone-bis-p-hydroxybenzoate (OH-Dreikerner) is not redily biodegradable.

Executive summary:

The test substance Hydroquinone-bis-p-hydroxybenzoate (OH-Dreikerner) was investigated for its ready biodegradability in a closed Bottle Test over a period of 28 days according to OECD Guideline 301D (1992) under GLP.

Under the test conditions the percentage biodegradation of Hydroquinone-bis-p-hydroxybenzoate (OH-Dreikerner) reached in the mean 12.1% after 28 days. The percentage biodegradation did not exceed 60% and can therefore not considered to be ready biodegradable. Both the refernce and the toxicity control were well within validity criteria.