Cyclohexyldimethylammonium dihydrogen phosphate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

May 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

April 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate 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.
All samples were stored frozen (at about -20 ± 5 C) immediately after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test item (100 mg) was dissolved in test water and the volume adjusted to 1 litre to give the 100 mg/L test concentration. The prepared concentration was inverted several times to ensure adequate mixing and homogeneity.
- Controls: test water

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flee
- Source: in-house culture
- Age at study initiation: < 24 h

Adult daphnia were maintained in 150 mL glass beakers containing Elendt M7 medium in a temperature controlled room at approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods.

Cultures were fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension.
Culture conditions ensured that reproduction was by parthenogenesis.

Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.
The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

- Feeding during test: none

ACCLIMATION
- Acclimation period: not relevant, conditions were comparable for maintenance and testing

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

250 mg CaCO3/L

Test temperature:

20 °C

pH:

6.9 - 7.4

Dissolved oxygen:

≥ 8.7 mg O2/L

Nominal and measured concentrations:

nominal concentration: 100 mg/L
measured concentration: 95 and 84 % of nominal (test start and end)
The biological results are based on the nominal concentration of the test item.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass jars containing approximately 200 mL test medium, covered
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 40 mL/animal

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (ISO medium) according to the guidelines.
- Ca/Mg ratio: 4:1
- Culture medium different from test medium: yes (daphnids were cultured in Elendt M7 Medium)
- Intervals of water quality measurement: water temperature was recorded daily, oxygen concentration and pH were measured at the start and at the end of the test.

OTHER TEST CONDITIONS
- Adjustment of pH:no
- Photoperiod: photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods
- Lighting: 507 to 528 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Daphnids were inspected for immobility and sub-lethal effects after 24 and 48 hours of exposure.

RANGE-FINDING STUDY
- Results used to determine the conditions for the definitive study: no toxic effects up to and including nominal 100 mg/L.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

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:

other:

Remarks:

mobility and sub-lethal effects

Details on results:

Behavioural abnormalities:
- Other biological observations: no adverse effects were observed
- Mortality of control: none
- Other adverse effects control: none

The test preparations were clear solution throughout the test period of 48 hours.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels:
- 24-hour EC50: 0.75 mg/L, 95% confidence limits 0.69 - 0.82 mg/L (within the range 0.6 – 2.1 mg/L as given by the guidelines)

Reported statistics and error estimates:

The EC50 value and the NOEC value were determined directly from the raw data.

Validity criteria fulfilled:

yes

Remarks:

In the control, not more that 10 % of the daphnids have been immobilised or showed other sub-lethal effects; the dissolved oxygen concentration at the end of the test was > 3 mg/L in all vessels.

Description of key information

48-h EC50 > 100 mg/L for Daphnia magna (OECD 202, EU C.2)

Additional information

EC50/LC50 for freshwater invertebrates: > 100 mg/L