N-(2,5-dimethoxyphenyl)acetamide

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well performed study according to valid guidelines at that time, but without GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: DIN 38 412 Part 25 (1984)

Deviations:

no

Principles of method if other than guideline:

The Zahn-Wellens test was conducted according to DIN 38 412 Part 25 (1984). This method is
corresponding with small differences to the Guideline OECD 302B.
In the Zahn-Wellens test biodegradation is determined by measuring the disappearance of DOC (DOC:
dissolved organic carbon). The method is used to test for inherent biodegradability. It specifies that the
amount of degraded DOC within the test period of normally 28 days exceeds 70 %. But, well
biodegradation in the Zahn-Wellens test does not allow an estimation of the "ready biodegradability"
according to the OECD Guidelines for Testing of Chemicals. Substances, which are degraded in the
range of 20 % to 70 % in the Zahn-Wellens-Test, are classified as primarily or slowly biodegradable.
DOC disappearance in the first three hours is caused by adsorption effects. If this occurs, the total DOC
disappearance is called "elimination", and the biodegradation is calculated by setting the value after 3 h
for 100 %. Adsorption effects may be specific for the used sludge and could lead to different results in
respect to the total elimination when the same method is performed with another source of bacteria.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

N-(2,5-dimethoxyphenyl)acetamide

EC Number:

222-423-1

EC Name:

N-(2,5-dimethoxyphenyl)acetamide

Cas Number:

3467-59-2

Molecular formula:

C10H13NO3

IUPAC Name:

N-(2,5-dimethoxyphenyl)acetamide

Details on test material:

purity: 99.5 %

Study design

Oxygen conditions:

aerobic

Details on inoculum:

Activated sludge from the sewage treatment plant of the
Hoechst AG at Frankfurt am Main, Höchst, mixed with activated
sludge from the sewage treatment plant at Hoechst AG, site
Kelsterbach

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

479.3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Reference substance

Reference substance:

diethylene glycol

Remarks:

concentration: 271.6 mg DOC/L

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

3 h

% Degradation 2

Parameter:

% degradation (DOC removal)

Value:

19

Sampling time:

5 d

% Degradation 3

Parameter:

% degradation (DOC removal)

Value:

36

Sampling time:

10 d

% Degradation 4

Parameter:

% degradation (DOC removal)

Value:

28

Sampling time:

17 d

% Degradation 5

Parameter:

% degradation (DOC removal)

Value:

60

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

Time % degradation for diethyleneglycol
3h 8
10 67
17 94
24 100

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: evidence of inherent, primary biodegradability

Conclusions:

The results of testing the biodegradability in the Zahn-Wellens Test revealed that:
N-(2,5-dimethoxyphenyl)acetamide shows evidence of inherent primary biodegradability.