2,2'-[azobis(1-methylethylidene)]bis[4,5-dihydro-1H-imidazole dihydrochloride

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:

10.11.-14.11.14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study according OECD guideline under GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (STRAUS)
- Strain: Clone 5
- Source: Institut für Wasser-, Boden- und Lufthygiene (WaBoLu), Berlin, Germany
- Age at study initiation (mean and range, SD): 2 to 24 h old daphnids were used
- Weight at study initiation (mean and range, SD): -
- Length at study initiation (length definition, mean, range and SD): -
- Valve height at study initiation, for shell deposition study (mean and range, SD): -
- Peripheral shell growth removed prior to test initiation: -
- Method of breeding:
- Feeding during test
- Food type: no feeding
- Amount: no feeding
- Frequency: no feeding

ACCLIMATION
- Acclimation period: not necessary, as test was performed in culture medium
- Acclimation conditions (same as test or not): -
- Type and amount of food: -
- Feeding frequency: -
- Health during acclimation (any mortality observed): -

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

18-22 °C, constant within ± 1 °C

Nominal and measured concentrations:

12.5 - 25.0 - 50.0 - 100.0 - 200.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers, 50 mL
- Type (delete if not applicable): closed (with watch glasses)
- Material, size, headspace, fill volume: glass, 50 mL, 20 mL fill volume
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate): renewed after 24 h; new set of test vessels and transfer of daphnids by a pipette
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): -
- Biomass loading rate:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4 medium, hardness modified to 160 to 180 mg CaCO3/L
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod:
- Light intensity: darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

potassium dichromate (purity: 99.9 %, Sigma)

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

87.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

29.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Mortality:
- EC50/LC50: 1.57 (1.53-1.60) mg/L
- Other:

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal concentrations of the test item Azo Initiator VA044, the 48h-EC50 for Daphnia magna was 87.1 mg/L (95 % confidence limits: 70.7 - 106 mg/L).

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item Azo Initiator VA044 (batch no: N10415) were determined according OECD 202 (2004), equivalent to the Council Regulation (EC) No 440/2008 Method C.2 (2008) from 2014 -11 -12 to 2014 -11 -14 at Dr. U.Noack-Laboratorien, Käthe-Paulus-Str. 1, D-31157 Sarstedt, Germany.

The study was conducted under semi-static conditions over a period of 48 h with 5 concentrations of the test item in the range of 12.5 to 200 mg/L, prepared with dilution water in a geometric series with a seperation factor of 2.

The test item is a white powder and is very soluble in water. As the test item is a light-sensitive substance, the study was performed in darkness. The stock solution of 200 mg/L was freshly prepared with dilution water before the start of both exposure intervals (at 0 and 24 h). Further test concentrations were prepared by diluting the stock solution of 200 mg/L with dilution water. The tested solutions were visually clear throughout the exposure period. Twenty Daphnids were exposed to each concentration level and control.

The concentrations of the test item were analytically verified via LC-MS/MS at the start of the exposure intervals (0 and 24 h) and at the end of the exposure intervals (24 and 48 h) in all concentration levels and the control. The measured concentrations of the test item at the start of the expoure intervals were in the range of 108 to 120 % of the nominal values. At the end of the exposure intervals the concentrations were in the range of 98 to 110 % of the nominal concentrations. These findings indicate that the test item concentrations were successfully maintained for the duration of the experiment.

The water quality parameters (i.e. pH-value and dissolved oxygen concentration), measured at the start and the end of the exposure intervals were within the acceptable limits. The validity criteria of the test guidelines were fulfilled.

Description of key information

Based on the findings in the available OECD 202 study exposing Daphnia magna with the substance an EC50 value of 87.1 mg/L is identified. This value is used for the further chemical safety assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

87.1 mg/L