Pyrocatechol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

This experiment is issued from a publication testing the biodegradability of catechol in several different tests. All of them showed uniform results concluding catechol is well biodegraded. This consistency of the results reinforce the reliability of the global publication. The present experiment is relatively well described, with the restrictions that the 10-day window criterion and the purity of catechol are not mentioned.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Deviations:

yes

Remarks:

3-20 mg/L catechol instead of 10-40 mg/L recommended, increased ammonium concentration in the medium

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: see details on inoculum.

Details on inoculum:

- 0.05% of a sludge of sewage treatment plant was used.
- No acclimatation.
No further data.

Duration of test (contact time):

19 d

Initial conc.:

3 - 20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Composition of medium: In order to maintain an optimal C:N:P ratio the ammonium concentration specified in the OECD program was tripled. Assay medium was a mineral nutrients solution supplied with trace elements and vitamins, and was added in order to optimize the test conditions.
No further data.

Parameter:

% degradation (DOC removal)

Value:

91

Sampling time:

19 d

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Catechol is readily biodegradable under the tested conditions.

Executive summary:

In a study (Gericke, 1979), the biodegradability of the substance Catechol (unknown purity, initial concentration: 3 - 20 mg/L), was tested in a modified OECD screening test during 19 days, according to OECD guideline 301E.

Inoculum used in this study was 0.05% of non-adapted effluent.

The percentage of biodegradation was estimated by following the DOC removal.

The corresponding percentage of biodegradation obtained after 19 days was 91%.

Under the test conditions, Catechol is considered as readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

This experiment is issued from a publication testing the biodegradability of catechol in several different tests. All of them showed uniform results concluding catechol is well biodegraded. This consistency of the results reinforce the reliability of the global publication. The present experiment is relatively well described, with the restrictions that the 10-day window criterion and the purity of catechol are not mentioned.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Prolonged test duration, and catechol concentration lower than the value recommended by the guideline

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: see details on inoculum.

Details on inoculum:

- 1 drop of sewage treatment plant effluent added per litre was used. 
- No acclimatation.
No more data.

Duration of test (contact time):

30 d

Initial conc.:

1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: BOD

Details on study design:

no data

Parameter:

other: BOD

Value:

89

Sampling time:

30 d

Details on results:

No more data

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Catechol is readily biodegradable under the tested conditions.

Executive summary:

In a study (Gericke, 1979), the biodegradability of the substance Catechol (unknown purity, initial concentration: 1 mg/L), was tested in a closed bottle test during 30 days, according to OECD guideline 301D.

Inoculum used in this study was non adapted and added as one drop of sewage treatment plant effluent per litre.

The percentage of biodegradation was estimated by following the biochemical oxygen demands as a percentage of the theoretically possible amounts (BODth).

The corresponding percentage of biodegradation obtained after 30 days was 89%.

Under the test conditions, Catechol is considered as readily biodegradable.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

This experiment is issued from a publication testing the biodegradability of catechol in several different tests. All of them showed uniform results concluding catechol is well biodegraded. This consistency of the results reinforce the reliability of the global publication. The present experiment is relatively well described, with the restriction that the purity of catechol is not mentioned.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

not specified

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, non-adapted

Details on inoculum:

The inoculum was prepared in accordance with the procedure of the Japanese MITI test. 30 mg/L of sludge was used. It was collected in the closer surroundings of the laboratory (these encompass many different industries).

Duration of test (contact time):

14 d

Initial conc.:

50 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

other: and the corresponding BOD

Details on study design:

- Principle:  Die-away mineral nutrients.
- Measuring equipment: In the study, a BOD determination apparatus (Sapromat) was used, with an electrolytic oxygen supply for its conduction.
No further data.

Parameter:

other: BOD

Value:

80

Sampling time:

14 d

Parameter:

% degradation (DOC removal)

Value:

88

Sampling time:

14 d

Details on results:

no data

Validity criteria fulfilled:

yes

Remarks:

according to the authors

Interpretation of results:

readily biodegradable

Conclusions:

Catechol is readily biodegradable under the tested conditions.

Executive summary:

In a study (Gericke, 1979), the biodegradability of the substance Catechol (unknown purity, initial concentration: 50 mg/L), was tested in a modified MITI test during 14 days, according to OECD guideline 301C.

Inoculum used in this study was an activated sludge, industrial, non-adapted at the concentration of 30 mg/L and was collected in the closer surroundings of the laboratory.

The percentage of biodegradation was estimated by following two parameters, the DOC removal and the corresponding biochemical oxygen demands (BODth).

The corresponding percentages of biodegradation obtained after 14 days were 88 and 80% respectively.

Under the test conditions, Catechol is considered as readily biodegradable.

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

This experiment is issued from a publication testing the biodegradability of catechol in several different tests. All of them showed uniform results concluding catechol is well biodegraded. This consistency of the results reinforce the reliability of the global publication. The present experiment is relatively well described, with the restrictions that the 10-day window criterion and the purity of catechol are not mentioned.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

"Sturm test"

Deviations:

not specified

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: see details on inoculum

Details on inoculum:

- 28-day test: the inoculum underwent no preacclimation procedure, and corresponded to raw sewage.
- 42-day test: the inoculum underwent a preacclimation procedure, and corresponded to 10% of a sludge of a sewage treatment plant effluent.

Duration of test (contact time):

28 - 42 d

Initial conc.:

10 mg/L

Based on:

other: test mat. / Remarks: concentration used in the 28-day test.

Initial conc.:

20 mg/L

Based on:

other: test mat. / Remarks: concentration used in the 42-day test.

Parameter followed for biodegradation estimation:

other: CO2 evolution after 28 days

Parameter followed for biodegradation estimation:

other: DOC removal after 42 days

Details on study design:

This test employed a preacclimation procedure. The preacclimation was modified in such a way that 20 mg/L of material, 20 mg/L of yeast extract, and 10% of sewage treatment plant effluent rather than raw sewage were added to BOD water in order to avoid anaerobic conditions.
No further data.

Parameter:

% degradation (CO2 evolution)

Value:

62

Sampling time:

28 d

Parameter:

% degradation (DOC removal)

Value:

96

Sampling time:

42 d

Remarks on result:

other: including preacclimation period

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Catechol is readily biodegradable under the tested conditions.

Executive summary:

In a study (Gericke, 1979), the biodegradability of the substance Catechol (unknown purity), was tested in a Sturm test during 28 days (without preacclimation, initial catechol concentration: 10 mg/L) and 42 days (with preacclimation, initial catechol concentration: 20 mg/L), according to OECD guideline 301B.

Inoculum used in this study was raw sewage for the 28-day test without preacclimation, and 10% of a sludge of a sewage treatment plant effluent for the 42-day test with preacclimation.

The percentage of biodegradation was estimated by following the CO2 evolution (without acclimation), and the DOC removal (with acclimation).

The corresponding percentages of biodegradation obtained were 62% of CO2 evolution after 28 days, and 96% of DOC removal after 42 days.

Under the test conditions, Catechol is considered as readily biodegradable.

Reference 5

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

Remarks:

The test was performed according to the internationally recognized OECD Guideline 301C and the data were validated by the Japanese competent authorities, but some data are lacking, as the test substance purity.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Deviations:

not specified

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: sludge sampling were made at 10 sites (specified in CERI book)
- Laboratory culture: yes
- Method of cultivation: about 30 min after ceasing the aeration of the sludge mixture, supernatant corresponding to about 1/3 of the whole volume was removed. Then the equal volume of dechlorinated water was added to the remaining portion and aerated again, followed by addition of synthetic sewage, in order the concentration of that portion was 0.1% (w/v). This procedure was repeated once every day. The culturing was carried out at 25+/-2°C.
- Storage conditions and storage length: no data
- Preparation of inoculum for exposure: 5 L of the filtrate of the supernatant of an activated sludge in the present use was mixed with 500 ml of the filtrate of the supernatant of a newly collected sludge respectively and the mixture was cultured at pH 7 +/- 1 under sufficient aeration (prefiltered air was used).
- Pretreatment: no
- Concentration of sludge: 30 mg/L
- Initial cell/biomass concentration: no data

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

TOC removal

Remarks:

(direct analysis)

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

(indirect analysis)

Details on study design:

TEST CONDITIONS
- Composition of medium: Each 3 ml of solution A, solution B, solution C and solution D, which are prescribed in JIS K 0102-1986-21 (Japanese Industrial Standards), were made up to 1000 ml with purified water, and then pH of this solution was adjusted to 7.
- Additional substrate: no
- Test temperature: 25+/-1°C
- pH: 7
- pH adjusted: yes
- Aeration of dilution water: no data
- Suspended solids concentration: 30 mg/L
- Continuous darkness: no data

TEST SYSTEM
- Culturing apparatus: closed system of 300 ml in volume
- Number of culture flasks/concentration: no data
- Method used to create aerobic conditions: absorbance of CO2
- Measuring equipment: dissolved oxygen concentrations
- Details of trap for CO2 and volatile organics if used: absorbent for CO2: Soda lime n°1 (extra pure reagent, Wako Pure Chemical Industries, Ltd).

SAMPLING
- Sampling frequency: once at termination of experiment
- Sampling method: no data

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1 flask
- Abiotic sterile control: yes with purified water but without sterilizing agent, 1 flask
- Toxicity control: no
- Other: flask with sludge+aniline= procedure control.

STATISTICAL METHODS: no data

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

14 d

Parameter:

% degradation (TOC removal)

Value:

96

Sampling time:

14 d

Results with reference substance:

No data

Validity criteria fulfilled:

not specified

Remarks:

Cf. "Conclusions" below

Interpretation of results:

readily biodegradable

Conclusions:

The substance attained 96% degradation in 14 days, based on TOC removal, and 83 % based on O2 consumption, and is therefore considered to be readily biodegradable.

Fulfilment of validity criteria:
- The report states that activity of the inoculum was checked by biodegradation testing of the reference substance aniline, which was expected to exceed 60% degradation by BOD by day 14. However, results are not reported for individual studies therefore it is not possible to confirm that the pass level was achieved for this study.

- No kinetic data were reported for the test substance.

- There are insufficient data to confirm whether degradation values in replicates did not differ by more than 20 % at the end of the test.

Executive summary:

This ready biodegradation study has been performed according to OECD test guideline (301C) by the Japanese Competent Authorities. The biodegradation of Catechol was followed during 14 days, at an initial concentration of 100 mg/L using a mixed, non adapted inoculum (30 mg/L). After 14 days, the measured percentage of biodegradation was 83 %(based on Biological Oxygen Demand) and 96% (based on Total Organic Carbon). Even if it is not possible to verify that validity criteria were indeed fulfilled, one can conclude on the basis of this study that Catechol is readily biodegradable.

Description of key information

One study (MITI, 1992) was selected as a key study. Although GLP were not mentioned and validity criteria were not available, this study was performed according to the OECD guideline 301C and was generated by the Japanese Competent Authorities. In this study, the biodegradation of Catechol was followed during 14 days, at an initial concentration of 100 mg/L using a mixed, non adapted inoculum (30 mg/L). After 14 days, the measured percentages of biodegradation were 83 % based on O2 consumption and 96 % based on TOC removal. On the basis of this study, Catechol is readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

One study (MITI, 1992) was selected as a key study. Although GLP were not mentioned and validity criteria were not available, this study was performed according to the OECD guideline 301C and was generated by the Japanese Competent Authorities. In this study, the biodegradation of Catechol was followed during 14 days, at an initial concentration of 100 mg/L using a mixed, non adapted inoculum (30 mg/L). After 14 days, the measured percentages of biodegradation were 83 % based on O2 consumption and 96 % based on TOC removal. On the basis of this study, Catechol is readily biodegradable.

 

In an another publication, selected as a supporting study (Gerike, 1979), Catechol was tested in different tests, all in accordance with the OECD guidelines. The results were the followings:

- OECD guideline 301B: 62 % biodegradation after 28 days based on CO2 evolution, 96 % after 42 days based on DOC removal.

- OECD guideline 301C: 88 % biodegradation after 14 days based on DOC removal.

- OECD guideline 301D: 89 % biodegradation after 30 days based on BOD.

- OECD guideline 301E: 91 % biodegradation after 19 days based on DOC removal.

Based on the results obtained in these different studies, Catechol is therefore considered as readily biodegradable.