4-Piperidinone, 2,6-diethyl-2,3,6-trimethyl-1-(1-phenylethoxy)-

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:

2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed following OECD- and EEC-Guidelines under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Details on test material:

ldentity: TKA 40270 (CGPS 345)
Batch no.: NE 3499-019-A
Expiration date: December 31, 2005
Purity: See Analytical Report 140351 27-1; 8,12.2003; Ciba
Specialty Chemicals Inc. Excluded from the GLP
Statement of Compliance
Aggregate state/physical form
under storage conditions: Liquid
Storage conditions: Room temperature (approx. 20 °C) away from
direct sunlight

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, adapted

Details on inoculum:

The study was performed with aerobic activated sludge from a wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) treating predominantiy domestic wastewater. The sludge was washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

20.1 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

For analysis of the CO2 content, samples were taken an Day 2, 5, 7, 9, 12, 14, 19, 23, 27,28 and 29.
On each sampling day, an aliquot of 5,0 mL was withdrawn from the absorber flask nearest ta the test flask für analysis of inorganic carbon (IC). Additional samples for analysis of IC were withdrawn from the second absorber fiask at the end of the exposure period an Day 28 in order to correct any carry over of CO2.
After sampling an Day 28, the pH was measured in each test flask. Next, 1 mL of concentrated HCI was added to each test flask and the flasks were aerated overnight to drive oft any residual CO2 present. On Day 29, a sample from each absorber flask was withdrawn and analyzed für IC to determine residual CO2 which was present in the test suspensions on Day 28. In this way, any residual CO2 remaining in the test suspensions was determined as the difference between the amount of IC found before and after acidification.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Preliminary study:

No preliminary study performed

Test performance:

One day before test start (Day -1), between 2400 and 3000 mL of untreated test medium was fllled into 5 liter flasks (amber glass). To each flask
(except for the abiotic control and the abiotic control blank), 90 mL of activated sludge inoculum was added,
For the abiotic control and the abiotic control blank, the untreated test medium was poisoned with mercury dichloride at a concentration of 10 mg/L (3 mL of a stock solution containing 10 g HgCl2/L filled up to 3 liter test medium).
The test media were aerated with CO2 free air overnight to purge the system of carbon dioxide.
On the following day (Day 0), defined amounts of the homogenized test item were weighed and thereafter transferred into the test flasks with 500 or 510 ml test water. For dosage of the reference item, a stock solution containing 770 mg sodium benzoate per 100 mL test water (purged with CO2
free air) was prepared. From this, 10 mL aliquots were added to the corresponding test flasks. Na emulsifiers or solvents were used. The test flasks
were made up to a volume of three liters with test water (purged with CO2 free air). Twa absorber flasks, the first one containing 300 mL of 0.05 M
NaOH and the second one containing 200 mL of 0.05 M NaOH, were connected in series to the exit air line of each test flask.

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

-2.6

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

-3.8

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

-2.8

Sampling time:

23 d

% Degradation 4

Parameter:

% degradation (CO2 evolution)

Value:

-2.2

Sampling time:

28 d

BOD5 / COD results

Results with reference substance:

The percent biodegradation of the reference item was calculated based an a total carbon content (TOC) of 0.58 mg C/mg sodium benzoate.
In the procedure controls, the reference item degraded by an average of 76% by exposure Day 14, thus confirming suitability of the activated siudge (>60% degradation by Day 14). By the end of the test (Day 28), the reference item degraded by an average of 94%.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

TKA 40270 (CGPS 345) was not biodegradable under the test conditions within 28 days.