N-[2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyphenyl]acetamide

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: screening test, other

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: Methods for the Examination of Waters and Associated Materials

Principles of method if other than guideline:

The principle of the BOD test involves measurement of the reduction in dissolved oxygen in the presence of the test sample and naturally occurring bacteria. The biological seed is obtained from a river, downstream of a sewage treatment works treating mainly domestic sewage. A bottle is set up containing dilution water seeded with bacteria (the blank). An aliquot of test material or stock solution is added to dilution water to give the required concentration for the test. Initially two different test concentrations are set up.

The dissolved oxygen concentration is measured in all bottles at the start of the test (Day 0 of measurement) and 5 days after the start, and the oxygen consumption of the test substance calculated by comparison of the loss of DO with the loss of DO in the blank. The BOD of the sample is calculated in mg O2 consumed per gram of test substance and degradation is reported as a percentage of the COD of the sample.

The COD involves oxidation of the test sample under standard conditions by acidified dichromate, and titration of the residual dichromate with ferrous ammonium sulphate solution.

GLP compliance:

yes

Inoculum or test system:

activated sludge, domestic, adapted

Duration of test (contact time):

ca. 5 d

Initial conc.:

ca. 40 mg/L

Key result

Parameter:

other: BOD5/COD

Value:

ca. 3.8

Sampling time:

5 d

Details on results:

BOD of the test solution: 0.6 mg O2/L
Measured BOD value

Key result

Parameter:

BOD5

Value:

ca. 20 mg O2/g test mat.

Key result

Parameter:

COD

Value:

ca. 520 mg O2/g test mat.

Validity criteria fulfilled:

not specified

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the experimental conditions biodegradation of the test substance was equivalent to 3.8%.

Executive summary:

A study was conducted to determine the biodegradability of the test substance (97.4% purity) based on BOD and COD in a 5-d study. The test involved measuring reduction in dissolved oxygen in the presence of the test substance. Biological inoculum was obtained from a river, downstream of a treatment plant handling mainly domestic sewage. A bottle was set up containing dilution water seeded with the bacteria (blank). An aliquot of the test substance stock solution was added to dilution water to give the required concentration for the study. The dissolved oxygen concentration was measured in all bottles at test start (Day 0) and after 5 d. Oxygen consumption was calculated by comparing dissolved oxygen (DO) loss in the test substance samples versus controls. The BOD of the sample was calculated in mg O2 consumed per gram of test substance and degradation was reported as a percentage of sample COD. The COD involves oxidation of the test substance under standard conditions by acidified dichromate and titration of the residual dichromate with ferrous ammonium sulphate solution. Under the experimental conditions, biodegradation of the test substance was equivalent to 3.8% (Yorkshire, 1993).

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Micro-organisms from a domestic waste water sewage plant (Ara Birsig, Therwil/Switzerland)

Duration of test (contact time):

ca. 28 d

Details on study design:

Apparatus: 50 ml Erlenmeyer flasks loosely covered with an aluminium foil
Test medium: The test medium (30 mL per flask) was prepared according to OECD 301 E (4)
Test concentration: Since the substance was insoluble in water, it was dispersed in the test medium and thereafter filtered through a fluted filter paper. The DOC of the filtrate was then determined. The concentration of the test article corresponded to 28.5 mg DOC/l.
The concentration of the standard (aniline) was 24.8 mg DOC/l. In addition an untretaed inoculated control was run. All samples were run in duplicate

Test conditions: The study was run at 20-25°C protected from light. The inoculated flasks were incubated in a shaking water bath.

Sampling
Per sampling interval, two flasks were taken and analysed for DOC in duplicate. Samples were taken at day 0 (treatment day) 7, 14 and 28 of the incubation period. Water evaporation losses were compensated by adding distilled water.

Samples preparation: Sampls were centrifugated or filtered (pore size: 0.2 micrometres) and thereafter directly analysed. If analyses were performed later 0.05 ml of a 1% HgCl2 solution per 10 ml filtrate were added. Therefater, the samples were stored for 24 hours at 2-4 degrees centigrade or for a longer period of time at -18 degrees.

DOC analyses: DOC analyses were performed with the various filtrates using a Technicon carbon Analyser II,; Technicon Industrial Method N 451-76W) equipped with an automatic Data Processing System.

Reference substance:

aniline

Key result

Parameter:

% degradation (DOC removal)

Value:

ca. 0

Sampling time:

28 d

Details on results:

% degradation of aniline in 14 days = 98.3
Test substance concentration = not available
Aniline concentration : 32 mg/L

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the experimental conditions no degradation is observed for the tested substance.

Executive summary:

A study was conducted to determine the biodegradability of the test substance (97.4% purity) in accordance with OECD Guideline 301E (modified OECD screening test). Non-adapted wastewater treatment plant sludge was exposed to the equivalent of 28.5 mg DOC/L under aerobic conditions. Since the test substance was insoluble in water, it was dispersed in the medium and thereafter filtered through a fluted filter paper. The DOC of the filtrate was then determined. A positive control (aniline at 24.8 mg DOC/L) and an untreated inoculated control were also tested. Removal of dissolved organic carbon (DOC) was monitored for 28 d. No biodegradation of the test substance was observed, whereas aniline degraded by 98.3% within 14 d. This suggests that the substance is not readily biodegradable. The conclusion must however be regarded with caution since no analytical determination of concentrations was conducted and the substance is practically insoluble in water (Archroma, 1987).

Reference 3

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

10 Mar - 14 Apr 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

GLP compliance:

no

Specific details on test material used for the study:

ThOD = 33.9 mg O2/L

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

ARA Pro Rheno communal, Basel, 100 mg suspended solids/L

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Two bottles per substance

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

St. dev.:

0

Sampling time:

28 d

Results with reference substance:

90% after 14 d

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance was not found to be inherently biodegradable (0% biodegradation after 28 d based on O2 consumption).

Description of key information

The biodegradation of Disperse Blue 291:1 Br was assessed in a weight-of-evidence approach. The target substance was tested in an inherent biodegradability study (OECD 302C). The mean biodegradation rate after 28 d was 0% based on O2 consumption. As there is no data on ready biodegradability, an OECD 301 F test from the structural analogue source substance Disperse Blue 79:1 Br was used to evaluate this endpoint. Corresponding to the results known for >90% of disperse dyes, Disperse Blue 79:1 Br is also not readily biodegradable (0% after 28 d based on O2 consumption). This result is confirmed by a BOD5/COD screening test with a ratio of ca. 3.8 indicating no potential to be degraded by bacteria from activated sludge. Summarising, Disperse Blue 291:1 Br is neither considered inherently nor readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed