2,4,6,8-tetramethyl-1,3,5,7-tetraoxacyclooctane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March - July 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Identification: META Metaldehyde techn.
- Description at room temperature: White crystalline powder
- Expiry / Retest Date: 05 April 2016
- Storage Conditions: refrigerator (2-8°C), in the dark

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations, quadruplicate samples were taken from each treatment at the start and at the end of the test (after 48 hours). For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling. One set of two samples were analyzed immediately after sampling, the second set of two replicates was stored at approximately -20'C until analysis. The second set was stored only for a backup. The concentration of the test item was analytically measured in the duplicate test medium samples of the single test concentration taken at the start and end of the test. From the control, one of the quadruplicate samples was analyzed per sampling time, too.

Vehicle:

no

Details on test solutions:

A dispersion with the loading rate of 100 mg/L was prepared at the start of the test by dispersing 100.1 mg of the test item in 1000 mL of test water. This preparation was supported by ultrasonic treatment for 15 minutes and intense stirring on a magnetic stirrer over 3 hours in the dark and at room temperature, to dissolve a maximum amount of the test item in the dispersion. No auxiliary solvent or emulsifier was used. After the 3-hour stining period, the dispersion of the test item was filtered through a membrane filter (Whatman, Type NC45, pore size 0.45 pm) after preconditioning of the filter with about 200 mL of the dispersion. The negative pressure of the filtration unit was reduced (800 mbar) to
avoid losses of volatile components of the test item during filtration. The undiluted filtrate containing the maximum concentration of dissolved test item was used as the test medium. The test medium was prepared just before the start of the test. The preparation of the test medium was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, No. 23, 2000 IOECD, 2000].

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna Straus
- Strain/clone: 5
- Source: originally supplied by the University of Sheffield / UK in 1992. Since that time, the clone has been bred at the CRO in reconstituted water of the quality identical to the water quality used in the tests
- Food type & feeding during test: algal suspension of the green algae Desmodesmus subspicatus CHODAT or a mixture of this algal suspension and a commercial fish diet (Tetra Min@ Hauptfutter, supplied by TETRA-Werke, 49304 Melle / Germany).
- Frequency: three times a week
- Age: at the start of the test, the organisms used in the test were 6-24 hours old, by removing the offspring <24 hours before start of the test and were not first brood progeny

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Remarks on exposure duration:

The daphnids were observed for immobility after 24 and 48 hours of exposure (daphnids not being able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile).

Post exposure observation period:

None

Hardness:

250 mg/L as CaCO3

Test temperature:

The test was performed in a temperature-controlled room. The water temperature was maintained at 20-21" C with continuous monitoring.

pH:

The pH values of the test medium and control were between 7.7 and 7.9.

Dissolved oxygen:

At the beginning and end of the test period, the dissolved oxygen concentration in the test medium and control was at least 8.0 mg/L.

Salinity:

Freshwater used

Conductivity:

No data

Nominal and measured concentrations:

A limit test was performed, thus the only nominal concentration tested was 100 mg/L. The measured concentration of the test item in the test medium was 107 and 103 mg/L at the start and end of the test, respectively.

Details on test conditions:

Material:
The test was performed in 100-mL glass beakers filled with 50 mL of test medium. The test vessels were covered with glass plates to reduce the loss of water by evaporation and to avoid the entry of dust into the solutions. The test vessels were labeled with the study number and all necessary additional information to ensure unique identification.

Experimental Conditions:
The test was performed in a temperature-controlled room. The water temperature was maintained at 20-21°C with continuous monitoring. A 16-hour light to 8-hour dark cycle with a 30-minute transition period was used. Light intensity during the light period was approximately between 390 and 560 Lux. The daphnids were not fed during the test. For each treatment in the definitive test, 20 daphnids were used divided into four replicates of five daphnids each. The volume of test solution provided for each daphnid was 10 mL.

Reference substance (positive control):

yes

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Details on results:

In the control and at the nominal test concentration of 100 mg/L no immobilized daphnids were determined during the test period of 48 hours.

Results with reference substance (positive control):

Potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in March 2014 (48-hour EC50: 0.36 mg/L, showed that the sensitivity of the test organisms was within the internal historical range.

Reported statistics and error estimates:

No data

Validity criteria fulfilled:

yes

Conclusions:

The test item had no acute toxic effects on Daphnia magna up to the nominal concentration of 100 mg/L.

Executive summary:

The acute toxicity of the test item to Daphnia magna was determined in a 48-hour static test according to the EU test method C.2. A limit test was performed in accordance with the test guidelines to demonstrate that the test item has no toxic effect on the test organisms up to and including a nominal concentration of 100 mg/L. Thus, the only nominal concentration tested was 100 mglL. The measured concentration of the test item in the test medium was 107 and 103 mg/L at the start and end of the test, respectively. Thus, the test item was stable in the test medium over the test period of 48 hours. The biological results were therefore related to the nominal concentration of the test item. The preparation of the test medium was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000. In the control and at the nominal test concentration of 100 mg/L no immobilized daphnids were determined during the test period of 48 hours. Therefore, the 24h- and 48h-EC50 was found to be > 100 mg/l, the NOEC at 24h and 48h was 100 mg/l.

Description of key information

The acute toxicity of the test item to Daphnia magna was determined in a 48-hour static test according to the EU test method C.2. A limit test was performed in accordance with the test guidelines to demonstrate that the test item has no toxic effect on the test organisms up to and including a nominal concentration of 100 mg/L. Thus, the only nominal concentration tested was 100 mglL. The measured concentration of the test item in the test medium was 107 and 103 mg/L at the start and end of the test, respectively. Thus, the test item was stable in the test medium over the test period of 48 hours. The biological results were therefore related to the nominal concentration of the test item. The preparation of the test medium was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000. In the control and at the nominal test concentration of 100 mg/L no immobilized daphnids were determined during the test period of 48 hours. Therefore, the 24h- and 48h-EC50 was found to be > 100 mg/l, the NOEC at 24h and 48h was 100 mg/l.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Source: GLP-report