N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-diphenyl)-4,4'-diamine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study. Validy criteria fulfilled

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(Modified Sturm Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'diamine

IUPAC Name:

N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'diamine

Details on test material:

- Name of test material (as cited in study report): RXSS/91/404; N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'diamine
- Physical state: white powder
- Analytical purity: 99.66%
- Lot/batch No.: 011G

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- source of inoculum: the aeration stage of the Severn Trent Plc sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage
- Preparation of inoculum for exposure: activated sludge was homogenised for 10 min. The solids were settled and the supernatant filterd through Whatman GFA paper prior to testing.
- Concentration of sludge: usage rate = 1% inoculum

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

10 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

20 mg/L

Based on:

test mat.

Details on study design:

TEST CONDITIONS
- Test temperature: 21 +/- 1°C
- Aeration of dilution water: CO2-free air bubbled through solution (2 bubbles per second)
- stirring: continuously by magnetic stirrers
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5 L glass culture vessels, containing 3 L

SAMPLING
- Sampling frequency: first absorber at days 0, 1, 2, 3, 6, 8, 10, 14, 16, 21, 23, 27 and 28. Second absorber at days 0 and 28.
- Sampling method: CO2 absorption in 2 Dreschel bottles, 350 mL 0.05 M NaOH
On day 27 pH of each vessel was measured, and 1 mL concentrated HCl added to drive off inorganic carbonate. The vessels were aerated overnight and the final samples were taken from both absorber vessels on day 28.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

3

Sampling time:

28 d

Remarks on result:

other: both at 10 and 20 mg/L

Details on results:

Points of degradation plot (test substance):
0 % degradation after 1 d
0 % degradation after 2 d
1 % degradation after 3 d
0 % degradation after 6 d
0 % degradation after 8 d
0 % degradation after 10 d
0 % degradation after 14 d
0 % degradation after 16 d
0 % degradation after 21 d
2 % degradation after 23 d

BOD5 / COD results

Results with reference substance:

Points of degradation plot (reference substance):
1 % degradation after 1 d
5 % degradation after 2 d
9 % degradation after 3 d
31 % degradation after 6 d
48 % degradation after 8 d
60 % degradation after 10 d
82 % degradation after 14 d
94 % degradation after 16 d
90 % degradation after 21 d
89 % degradation after 23 d

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Test substance cannot be considered as ready biodegradable under the conditions of this test. However, testing was performed above water solubilitylevel.

Executive summary:

Biodegradation of N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'diamine was tested according to OECD 301 B (CO2 -evolution, modified Sturm Test)/ EU-Method C.3 over 28d using activated sludge as an inoculum. Tested concentrations were 10 mg/L and 20 mg/L which were above water solubility level. 3% biodegradation was observed after 28d. Under this conditions the test substance is regarded as not readily biodegradable.