2,6-dichloro-N-phenylaniline

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

other information

Study period:

January 17 - February 15, 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented and reported study, conducted equivalent to internationally accepted technical guideline in recognized research organization. Although IC and TC values of the test substance at test start are not indicated, the study is regarded as valid because CO2 evolution from endogenous respiration was as expected and degradation of the reference substance was as expected in the absence and presence of the test substance. Therefore, any influence of inorganic carbon can be excluded.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

, 1992

Deviations:

yes

Remarks:

: Only one CO2 scrubber was used

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2,6-dichloro-N-phenylaniline

EC Number:

239-349-0

EC Name:

2,6-dichloro-N-phenylaniline

Cas Number:

15307-93-4

Molecular formula:

C12H9Cl2N

IUPAC Name:

2,6-dichloro-N-phenylaniline

Details on test material:

Identification Code (as cited in study report): PBS 3247
Generic/Trade name: Dichlordiphenylamin dest.
BatchNo.: EN 322165.36
Appearance: beige solid
Purity: not available*
Solubility (in water): 0.0063 g/l
Received: 17/10/94
Storage: room temperature
Stability : 12/95
Theoretical carbon content: 60.53 % (purity of 100% assumed)

*: The test substance is identified by the code number. Identification and characterization is guaranteed by the sponsor. Data for purity were not available or not generated and documented according to the rules of Good Laboratory Practices.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
Activated sludge collected from the sewage treatment plant of CH-4153 Reinach on 21/11/94. The pH after collection was 7.6.
- Preparation of inoculum for exposure: The preparation was carried out according to the method described in the guideline.
- Pretreatment: Before application, the inoculum was pre acclimated to the test medium over night. The aeration was performed inside 1.2 l water, containing the amount of mineral salts for 1.5 l.

Duration of test (contact time):

29 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

24.9 - 26.4 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

15.1 - 16 mg/L

Based on:

other: ThOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: The test medium was prepared according to the method described in the guideline.
- Solubilising agent (type and concentration if used): TWEEN 80, 3 mg/l
- Application of the test substance: Pre acclimated inoculum (1.2 l, see details on inoculum) was made up to 1.5 l with a 300 ml mixture made from: the test substance in 285 ml bidistilled water and 15 ml (4.5 mg) vehicle Polyoxyethylen - Sorbitan monooleate : TWEEN 80 (Fluka 93781), which was applied as a stock solution of 300 mg/l. This mixture was homogenized and added to the test vessel, which was immediately connected to the CO2 scrubber.
- Test temperature: 22 ± 2 °C
- pH: no data
- pH adjusted: no data
- Aeration of dilution water: air purified from carbon dioxide
- Suspended solids concentration: no data
- Continuous darkness: diffuse light (dark brown glass flasks)

TEST SYSTEM
- Culturing apparatus: 2 Liter flasks (dark brown glass) equipped with gas inlet and magnetic stirrer
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: air (purified from carbon dioxide) at ca. 25 ml/min
- Measuring equipment: carbon analyzer (Shimadzu TOC-500)
- Test performed in open system: yes
- Details of trap for CO2: Approx 250 ml scrubbers with gas inlet tubes equipped with sintered glass tips containing 200 ml 0.05 N sodium hydroxide. Only one CO2 scrubber was used per test bottle. Theoretically, a solution of 0.05 M NaOH is sufficient to trap at least two times more CO2 than the maximum ThCO2 which can evolve in each test bottle (inc1uding CO2 possibly evolved from the bacteria e.g., endogenous respiration). Moreover, experimentally it was confirmed that no measurable CO2 carry over has ever occurred with the scrubbers used.


SAMPLING
- Sampling frequency:
- blanks and test substance: Day 0, 3, 6, 8, 10, 13, 17, 20, 24, 28, and 29. The last measurement was performed after acidification of the test medium with 1 ml of concentrated hydrochloric acid.
- reference and reference + test substance: Day Day 0, 3, 6, 8, 10, 13, 17, and 20. The specifications of biodegradation criteria were met by that time.
- Sample storage before analysis: samples were analyzed on the day of sampling

CONTROL AND BLANK SYSTEM
- Inoculum blank: test medium and inoculum, 2 flasks
- Abiotic sterile control: not performed
- Toxicity control: reference substance (15 mg DOC/l), test substance (16.5 mg/ThOC/l) and inoculum (1 flask, )
- Procedure control: reference substance (15 mg DOC/l) and inoculum (2 flasks)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

29 d

Details on results:

The test substance had no inhibitory effect on the biodegradation of the reference substance (biodegradation (based on the amount of reference item alone) was 58% within 3 days of exposure).

BOD5 / COD results

Results with reference substance:

The reference substance sodium benzoate was degraded by 61% within 3 days of exposure.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Criteria of OECD Guideline 301B for the reference and test substance and the blanks were fulfilled. IC and TC values of the test substance at test start are not indicated. However, the study is regarded as valid (see rationale for reliability).

Interpretation of results:

under test conditions no biodegradation observed

Executive summary:

The ready degradability of PBS 3247 was determined in a 28-d biodegradation study in accordance with OECD Guideline 301B (Determination of ‘ready’ biodegradability: carbon dioxide (CO2) evolution test (modified Sturm test)). The study was performed in compliance with GLP. Reliability grade 1 was assigned. Tested concentrations were 15.1 and 16.0 mg/l related to ThOC. Microbial activity was not inhibited. PBS 3247 was not readily biodegradable.