3,5-bis(2,4-dimethylcyclohex-3-en-1-yl)polyheterocycle

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:

2010-10-20 to 2010-12-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Aerobic activated sludge (micro-organisms from a domestic wastewater treatment plant) was supplied by the sewage works of Darmstadt, Germany.
The aerobic activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and centrifuged again. This procedure was done three times. The sediment was resuspended in test water and aerated overnight. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated ali­quots of washed sludge suspension, corresponding to 1.5 g dry material per litre were mixed with test water. This suspension was used for the experiment.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

ca. 103.5 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test Water Reconstituted Test Water: Analytical grade salts were added to deionised water to prepare the following stock solutions:
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl filled up with deionised water to 1000 mL volume
b) 22.5 g MgSO4 x 7 H2O filled up with deionised water to 1000 mL volume
c) 36.4 g CaCl2 x 2 H2O filled up with deionised water to 1000 mL volume
d) 0.25 g FeCl3 x 6 H2O filled up with deionised water to 1000 mL volume
In order to avoid precipitation of iron hydroxide in the stock solution d) after storage and before use, one drop of concentrated HCl per litre was added.
10 mL of stock solution a) and 1 mL of the stock solutions b) to d) were combined and filled up to a final volume of 1000 mL with deionised water. The pH-value was 7.5 and therefore no adjustment was necessary.
The amounts of test item and reference item were directly weighed into the test flasks. No emulsifiers or solvents were used, but the solutions were dispersed by stirring to achieve a homogeneous solution of the test item.
There were to replicates of "test item" and "inoculum control", and one "Procedure Control", "Abiotic Control" and "Toxicity Control", respectively.
The prepared test flasks were in­cubated at 22 ± 1 °C. The pressure decrease in the reaction vessels was measured over complete experimental phase of 28 days using the BSB Sensomat system, Aqualytic Dort­mund. The test flasks were closed gas-tight by a measuring head. Potassium hydroxide solution (45%) was used for trapping the produced carbon dioxide. The amount of O2 consumed by the activated sludge was calculated from the decrease of pressure in the reaction vessel.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

other: ThOD NO3

Value:

14

Sampling time:

28 d

% Degradation 2

Key result

Parameter:

other: ThOD NH4

Value:

15

Sampling time:

28 d

Details on results:

ThOD NH4
The occurrence of nitrification was considered but not ex-perimentally confirmed. If no nitrification occurs, the mean value for biodegradation was calculated to be 15% after 28 days. Therefore, the 10-day window criterion was not passed.

ThOD NO3
Based on ThODNO3 also no 10-day window was reached and the mean value for biodegradation was calculated to be 14% biodegradation after 28 days.

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was sufficiently de­graded to 75% after 14 days and to 82% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of Sa 57 (SAT No. 090073) did not reach 60% within the 10-day window and after 28 days of incubation when no nitrification is considered.
According to the test guideline, nitrification has to be con-sidered if nitrogen is part of the molecule. However, Sa 57 (SAT No. 090073) is considered not to be readily biodegradable.

Executive summary:

The test item Sa 57 (SAT No. 090073) was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the micro-organisms during expo­sure. As a reference item sodium benzoate was tested simul­taneously under the same conditions as the test item, and functioned as a procedure control.

The degradation rate of Sa 57 (SAT No. 090073) did not reach 60% within the 10-day window and after 28 days of incubation when no nitrification is considered.

According to the test guideline, nitrification has to be con-sidered if nitrogen is part of the molecule. However, Sa 57 (SAT No. 090073) is considered not to be readily biodegradable.