Cyclohexyl phenyl ketone

Biodegradation in water: screening tests

Administrative data

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:

other: Guideline study, well documented

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

1992

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Automatically generated during migration to IUCLID 6, no data available

IUPAC Name:

Automatically generated during migration to IUCLID 6, no data available

Details on test material:

- Name of test material (as cited in study report): TKA 40143
- Physical state: brown melt solid
- Analytical purity: 88.8%
- Lot/batch No.: PNr. 5021
- Expiration date of the lot/batch: December 01, 1997
- Storage condition of test material: At room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap de Maaskant', ‘s-Hertogenbosch, the Netherlands. The sludge was kept under continuous aeration until further treatment. The concentration of suspended solids was 3.9 g/L in the concentrated sludge. Before use, the sludge was allowed to settle for at least 30 minutes and the liquid decanted for use as inoculum at the amount of 10 ml/L of mineral medium.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

15 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

- Test suspension: containing test substance and inoculum (2 bottles).
- Inoculum blank: containing only inoculum (2 bottles)
- Positive control: containing reference substance (ca. 40 mg/l sodium acetate, TOC ca. 12 mg/l) and inoculum (1 bottle).
- Toxicity control: containing test substance, reference substance and inoculum (1 bottle).
- The temperature recorded during the study varied between 20 and 23°C.
- The pH recorded during the study varied between 7.4 and 7.8.
- CO2 evolution measured on days 2, 5, 7, 9, 14, 19, 23, 27, and 29

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

13

Sampling time:

28 d

Remarks on result:

other: replicate A

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

11

Sampling time:

28 d

Remarks on result:

other: replicate B

BOD5 / COD results

Results with reference substance:

74% in 14 days

Any other information on results incl. tables

In the toxicity control degradation just below the 25%-level (22%) occurred in 14 days (based on ThC02). On day 19 the degradation in the toxicity control was 25%. Thus, TKA 40143 was found to have borderline inhibiting properties on microbial activity. However, this was considered to have no effect on the outcome of this study.

Applicant's summary and conclusion

Interpretation of results:

other: poorly biodegradable