4,4'-[(1,10-dioxodecane-1,10-diyl)bis(oxy)]bis(2,2,6,6-tetramethylpiperidine-1-oxidanyl)

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

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:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

Adopted April 4, 1984,

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,10-bis(2,2,6,6-tetramethyl-1-piperidinyloxy)-1,10-dioxodecane

EC Number:

417-440-8

EC Name:

1,10-bis(2,2,6,6-tetramethyl-1-piperidinyloxy)-1,10-dioxodecane

Cas Number:

2516-92-9

Molecular formula:

C28 H50 N2 O6

IUPAC Name:

bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) decanedioate

Details on test material:

Identification code (lab) = TKA 40075

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
During the final test samples for analysis were taken from the control, the additive-control, the filtered and unfiltered solution of 100 mg/l.
- Sampling method:
Frequency: at t= 0h and t=48h.
Volume: 10 ml from the approximate centre of the test vessel.
- Sample storage conditions before analysis:
Samples taken at t=0h were stored in a deep- freeze until analysis. Samples taken at t=48h were analyzed on the day of sampling.

Test solutions

Vehicle:

yes

Remarks:

Cremophor EL as a dispersing agent.

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Tests solutions of 100 mg/l were prepared by adding quantitatively 29.5 (A: filtrate) or 29.3 mg (B: supersaturated solution) of test substance to 300 ml ISO-medium.
Since the solubility of the test substance in water was limited, Cremophor EL was used for the preparation of stock solutions. The final concentration of Cremophor EL in the test solutions was 100 mg/l.
The solutions were stirred for 94 hours. Subsequently, solution A was filtered through a paper filter and as such tested, i.e. 2 x 80 ml divided over 2 vessels. From solution B 2 x 80 ml were taken and tested without filtration.
Both test solutions were turbid. Undissolved test substance particles were observed in the supersaturated solution (B).

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: common water flea
- Strain/clone: not specified
- Source: laboratory culture
- Age of parental stock : maximum 4 weeks
- Feeding during test:
Daily, a volume of 0.25 ml of a Chlorella pyrenoidosa suspension with a cell density of 2*10^8 cells/ml was added to each vessel containing ca. 50 ml of test solution as feed for the daphnids i.e. a ration per organism of about 50*10^6 cells/day (corresponding with ca. 0.5 mg C/Daphnia/day).

ACCLIMATION
not specified

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

20.0 to 21.0°C

pH:

8.1-8.2

Dissolved oxygen:

9.3-9.5 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml, all-glass
- Aeration:
No aeration of the test solution, except when the presence of test substance induces oxygen depletion.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
ISO, prepared in milli-RO water

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
immobility

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
No range-finding test was performed.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 15.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

15.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

In the control, no daphnia became immobilized or trapped at the surface of the water. The analytical program provided clear evidence that the actual test concentration had been maintained at 80% of the initial concentration in the filtered solution. The unfiltered solution appeared to be an unstable dispersion.
Further, all test conditions remained within the ranges prescribed by the protocol.

Some effects were observed with the unfiltered 100 mg/L solution, which had undissolved test substance particle deposits on the bottom of the test vessel. These effects were probably related with the presence of larger test substance particles, which were not present in the filtered solution.

Results with reference substance (positive control):

The actual responses in this reference test are within the ranges of the expected responses at the different concentrations. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected at NOTOX.
The 24h-EC50 was 0.92 mg/l with 95 % fiducial limits of 0.83 and 1.07 mg/l. The 48h-EC50 of this test corresponded with 0.75 mg/l, i.e. the geometric mean between 0.56 (0 %) and 1.0 mg/l (100 %).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study, the 48h-EC50 of TKA 40075 (GU 10-415) for immobilization of daphnia was greater than the maximum attainable concentration of TKA 40075 (GU 10-415) in test medium (ca. 16 mg/l).

Executive summary:

Acute Toxicity Study in Daphnia magna with TKA 40075 (GU 10-415).

The study procedures described in this report were based on the EEC directive 92/69, Part C.2. "Acute toxicity for Daphnia" and the OECD guideline No. 202: "Daphnia sp., Acute Immobilisation Test", Adopted April 4, 1984,

The final test was a limit study exposing daphnia for a maximum of 48 hours to both a supersaturated solution of nominally 100 mg/l and its filtrate. The test solutions consisted of dispersions prepared with the use of Cremophor EL as a dispersing agent. These dispersions were stirred for ca. 94 hours before the start of the exposure. Subsequently, one of these dispersions was filtered through a paper filter and as such tested while the other was tested without filtration. Both were turbid while the unfiltered dispersion contained undissolved test substance particles dispersed through the medium. The test was performed in duplicate with 10 daphnia per vessel.

Analysis of the samples taken at the start (t=0) of the test showed that the exposure concentration in the unfiltered solution of nominal 100 mg/l was 82.3 mg/l, while a concentration of 16.6 mg/l was measured in the filtrate.

At the end of the exposure period, the measured concentrations had not decreased significantly in the filtrate. However, in the unfiltered solution the measured concentration had decreased to 14.7 mg/l.
This was most likely caused by deposits of undissolved test substance particles on the bottom of the test vessel.

Under the conditions of the present study, the 48h-EC50 of TKA 40075 (GU 10-415) for immobilization of daphnia was greater than ca. 16 mg/l, a supersaturated concentration of TKA 40075 (GU 10-415) in test medium.

The effects observed in daphnia exposed to the unfiltered solution of nominally 100 mg/l were probably related with the presence of larger test substance particles, which were not present in the filtered solution.