Benzoic acid, 3-amino-5-[[(2,3-dihydroxypropyl)amino]carbonyl]-2,4,6-triiodo-

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Version / remarks:

adopted 12 May 1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

rac-5-Amino-N-(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamic acid

EC Number:

601-093-6

Cas Number:

111453-32-8

Molecular formula:

C11 H11 I3 N2 O5

IUPAC Name:

rac-5-Amino-N-(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamic acid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Kläranlage Ruhleben, Berlin, Germany
- Pretreatment: The activated sewage sludge for the inoculum was collected on the day the experiment started from a municipal sewage treatment plant, predominantly dealing with domestic sewage. During the time between collection and use the sewage sludge was kept under aerobic conditions. Approximately 1 hour before the start of the incubation, aeration was discontinued and the sludge was allowed to sediment. The inoculum was obtained from the supernatant.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
The solutions were incubated on a shaker in darkness at a temperature of 20 - 25 °C for 29 days.

TEST SYSTEM
The final concentration of the test and reference substance was approximately 20 mg DOC/L in a volume of 1000 mL in each case. In order to reach this final concentration, the following quantities of the different solutions were mixed.
Sodium acetate: 67.8 mL of the stock soluti,on, 6 mL nutrient solution and 925.7 mL aqua dest.
ZK 39.211: 92.2 mL of the stock solution, 6 mL nutrient solution and 901.3 ml aqua dest.
0.5 mL of the inoculum was added to each test solution as well as the reference solution.

Additionally, a blank containing the nutrient solutions, aqua dest. and the inoculum was prepared. All test and reference substances including the blank were incubated in duplicate.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

The reference substance was degraded by 90 % between day 1 and day 4. This means that the quality criteria set by the OECD guideline (OECD, 1981) were fulfilled, i.e. the, inoculum was viable and active.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test compound Tamip monoamid (ZK 39.211) is not readily biodegradable.

Executive summary:

The biodegradation of Tamip monoamid was investigated following OECD 301E. Activated sludge was used as inoculum. After 28 d no biodegradation was observed (0% after 28 d). Thus, the test substance is not readily biodegradable according to the OECD criteria. The reference substance was degraded to 90% after 4 d indicating that the inoculum is viable and active.