3-hydroxy-2'-methoxy-2-naphthanilide

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:

1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to OECD 301 B with deviations

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

56 day study

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-hydroxy-2'-methoxy-2-naphthanilide

EC Number:

205-206-6

EC Name:

3-hydroxy-2'-methoxy-2-naphthanilide

Cas Number:

135-62-6

Molecular formula:

C18H15NO3

IUPAC Name:

3-hydroxy-N-(2-methoxyphenyl)naphthalene-2-carboxamide

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, Frankfurt-Sindlingen
- Pretreatment: according to guideline, the supernatant was decanted and maintained in an aerobic condition by aeration with for 3 days- 10 mL/L were used to initiate inoculation

Duration of test (contact time):

56 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

20.33 mg/L

Based on:

other: nominal concentration of test material

Initial test substance concentration 2

Initial conc.:

20.53 mg/L

Based on:

other: nominal concentration of test material

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS

- Test temperature: 20 ± 2°C; deviation on days 55 and 56 (16°C)

TEST SYSTEM
- Culturing apparatus: 5000 mL glass flasks
- Number of culture flasks/concentration: 2 for the reference item, 2 for the control, 2 for the test item
- Details of trap for CO2 and volatile organics if used: CO2 adsorption vessels were connected to the air outlets of the incubation vessels via a series of 3 vessels, each containing 100 mL of a 0.0125 mol/L Ba(OH)2 solution.

SAMPLING
- Sampling frequency: Backtitration of the residual Ba(OH)2 with 0.05 N HCL was carried out three times a week during the first ten days and thereafter twice weekly.
- Sampling method: 25 mL respectively were taken to determine the residual Ba(OH)2 by titration

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg/L

Results and discussion

Preliminary study:

Not performed

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

47.8

Sampling time:

56 d

Remarks on result:

other: mean of duplicates

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

15

Sampling time:

56 d

Remarks on result:

other: sample A

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

80.5

Sampling time:

56 d

Remarks on result:

other: sample B

Details on results:

The total amount of CO2 produced in 56 days was analysed by titration in 9 measurements respectively.
The test item reached the 10 % level (beginning of biodegradation) after a long lasting adaptation phase of 21 days.
The test item must be regarded as not readily biodegradable in the 10-d-window and after 28 days. In one of the two vessels the biodegradation was > 60 % after 56 days. Therefore the substance has to be regarded as potentially biodegradable.

BOD5 / COD results

Results with reference substance:

The course of the degradation was rapid and the functional control reached the pass level of 60 % within 7days. The validity criterion degradation >/= 60 % after 14 d is fulfilled.

Any other information on results incl. tables

Day of study	CO2-formation [mg C/L]
	100 % A = 14.99; 100 % B = 15.13					100 % = 11.61
	A	B	A [%]	B [%]	Mean [%]	Reference	[%]
3	0.15	0.39	1.0	2.6	1.8	3.75	32.3
7	0.25	0.59	1.6	3.9	2.8	7.59	65.3
14	0.31	0.73	2.1	4.8	3.4	9.64	83.0
21	0.46	2.87	3.0	18.9	11.0	10.47	90.1
27	0.59	4.33	3.9	28.6	16.2	10.66	91.8
34	0.67	6.85	4.4	45.2	24.8
41	0.70	8.72	4.6	57.6	31.1
55	1.14	10.40	7.6	68.7	38.1
56	2.26	12.19	15.0	80.5	47.8

A,B: Testsubstance

Applicant's summary and conclusion

Interpretation of results:

inherently biodegradable, not fulfilling specific criteria

Conclusions:

The test item must be regarded as not readily biodegradable in the 10 d-window and after 28 days.

Executive summary:

The ready biodegradability of the test item was determined with a non adapted activated sludge over a test period of 56 days in the Modified Sturm Test. The study was conducted according to OECD 301 B. The test item was tested at a concentration of 20 mg/L in duplicates, corresponding to a carbon content (DOC) of 15 mgC/L in the test vessels. The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO₂ produced by the respiration of bacteria. The degradation was stopped on day 56. The percentage CO₂production was calculated in relation to the theoretical CO₂production (ThCO₂) of the test item. The biodegradation rate was calculated for each titration time.

To check the activity of the test system, sodium benzoate was used as functional control. The percentage degradation of the functional control reached the pass level of 60 % after 7 days and came to a maximum of 91.8 % after 27 days.

The test item reached the 10 % level (beginning of biodegradation) after a long lasting adaptation phase of 21 days. Therefore the test duration was prolonged to 56 days. The degradation rate after 56 days was 15% and 80.5:%

The test item must be regarded as not readily biodegradable in the 10-d-window and after 28 days. In one of the two vessels the biodegradation was > 60 % after 56 days. Therefore the substance has to be regarded as potentially biodegradable.