α-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From May 16th to May 18th, 2013

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

no analytical monitoring.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

no analytical monitoring.

GLP compliance:

no

Remarks:

No justification provided.

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: For the stock solution 75.0 mg of test item was solved in 500 ml M4 medium so that the nominal concentration was 150 mg/l. Correction for the active content was
applied by using weighing correction factor (1.086 for Imidazol Ethanol (CAS No 24155-42-8)). Thus the actual concentration of the test item in the stock solution was 138.12 mg/l.
The stock solution was diluted with M4 medium to obtain working solutions with the following required concentrations: 0.69; 1.38; 2.76; 5.52; 11.05; 22.10 and 44.20 mg/l.
The range of concentration of the test item for the test was determined previously in a rangefinding test.
- Eluate: Elendt M4 medium.
- Controls: Elendt M4 medium.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: Straus
- Source: National Institute of Environmental Health
- Age of parental stock (mean and range, SD): The stock cultures contained Daphnia magna of different age. Occasionally the adult animals were separated by sieving to start a new breeding culture.
- Selection of daphnids: One day before starting the test, all of the juvenile daphnids were removed from the selected breeding cultures by sieving. These juvenile daphnids were disposed. Next day, the neonates (which are younger than 24 hours) were separated from the same parental culture by filtering and were transferred into test vessels.
- Age: < 24 hours neonates (not first brood progeny).
- Feeding during test: no.

ACCLIMATION
- Acclimation period: no. Elendt M4 media was used in breeding and test cultures according to OECD 202 guideline, to avoid the necessity of adaptation prior to the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21 (±1) °C

pH:

7.8 - 8.4.

Dissolved oxygen:

6.39 mg/L

Nominal and measured concentrations:

0.69; 1.38; 2.76; 5.52; 11.05; 22.10 and 44.20 mg/l (nominal).

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
- Type (delete if not applicable): closed (plastic lids)
- Material, size, headspace, fill volume: glass, 100 ml, 50ml, fill volume 50 ml.
- Aeration: no.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionised water was used for preparing the media. The media was sterilized by filtration.
- Culture medium different from test medium: no.

OTHER TEST CONDITIONS
- Adjustment of pH: no.
- Photoperiod: light/dark cycle of 16/8 hours.
- Light intensity: less than 1000 Lux.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): At 24 and 48 hours after the beginning of the test the percentage of the immobilised daphnids were determined. The daphnids were considered to be immobile if they were not able to swim within 15 seconds after gentle agitation of the test vessels. The pH and dissolved oxygen were measured at the beginning and the end of the test.

VEHICLE CONTROL PERFORMED: not applicable.

RANGE-FINDING STUDY
- Test concentrations: not specified.
- Based on the results of a range-finding study, the test item concentrations applied in the test were 0.69; 1.38; 2.76; 5.52; 11.05; 22.10 and 44.20 mg/l.

Reference substance (positive control):

yes

Remarks:

The sensitivity of the used Daphnia magna clone was tested with potassium dichromate according to MSZ EN ISO 6341:2012 on 09/12/2013.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

8.953 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

3.899 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Remarks on result:

not determinable because of methodological limitations

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

19.548 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no.
- Observations on body length and weight: no.
- Other biological observations: no.
- Mortality of control: 0/20.
- Other adverse effects control: no.
- Abnormal responses: no.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no.
- Effect concentrations exceeding solubility of substance in test medium: no.

- The NOEC and LOEC were determined with Fisher’s exact binominal test with Bonferroni correction. The results were inconclusive.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- ECx: The EC50 was 0.69 mg/l which met the requirements (0.6 – 2.1 mg/l).

Reported statistics and error estimates:

The effective concentrations (ECx) were determined including the 95 % confidence interval with Probit analysis using linear max. Likelihood regression.

Table 2. Counting of the immobilised daphnids.

Test item (mg/l)	24 h					48 h
	Beakers				Sum (%)	Beakers				Sum (%)
	1	2	3	4		1	2	3	4
Control	0	0	0	0	0	0	0	0	0	0
0.69	0	0	0	0	0	0	0	0	0	0
1.38	0	0	0	0	0	0	0	0	0	0
2.76	0	0	0	0	0	0	0	1	0	5
5.52	0	0	0	0	0	1	1	1	1	20
11.05	1	0	0	0	5	4	2	3	4	65
22.10	3	4	3	4	70	5	5	4	4	90
44.20	4	5	5	5	95	5	5	5	5	100

 

Table 3. Measurement of pH and dissolved oxygen.

Test item (mg/l)	Test vessel No.	Start of the test		End of the test
Control	29	8.12	5.76	7.90	5.62
	30			7.91	5.69
	31			7.90	5.61
	32			7.90	5.49
44.20	1	8.34	6.39	7.78	5.72
	2			7.83	5.62
	3			7.86	5.63
	4			7.88	5.72

 

Table 4. Determination of effective concentrations.

	24 h (mg/l)	48 h (mg/l)
EC10	11.612	3.899
EC20	13.886	5.187
EC50	19.548	8.953

 

Validity criteria fulfilled:

yes

Remarks:

There was no immobilization in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.

Conclusions:

The 48h EC50 value of the test item on Daphnia magna is 8.953 mg/l.

Executive summary:

A short-term toxicity test on aquatic invertebrates was performed on the test item, according to OECD TG 202 / EU Method C.2, under GLP conditions. In accordance to a range-finding preliminary study, the nominal concentrations of test item used in the main experiment were: 0.69; 1.38; 2.76; 5.52; 11.05; 22.10 and 44.20 mg/l (nominal). Twenty daphnids (< 24 h old, 5 per replicate) were exposed to either a control medium or the test item concentrations specified for 48 hours under static conditions. No analytical monitoring was performed. The validity criteria were fulfilled. Based on the results obtained, the 48h EC50 value of the test item on Daphnia magna is 8.953 mg/L. No NOEC value was obtained.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

1. SOFTWARE: QSAR calculation by ECOSAR v1.11, EPA, USA

2. MODEL (incl. version number): ECOSAR v1.11

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL: CAS No. 24155-42-8 (input), SMILES: n1(CC(O)c2c(CL)cc(CL)cc2)cncc1.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- QMRF in 'Attached justification'

5. APPLICABILITY DOMAIN
- QPRF in 'Attached full study report'

Guideline:

other: REACH Guidance on QSARs R.6

Principles of method if other than guideline:

QSAR calculation by ECOSAR v1.11, EPA, USA (attached QSAR Prediction Reporting Format, QPRF).

Specific details on test material used for the study:

CAS No. 24155-42-8
SMILES: n1(CC(O)c2c(CL)cc(CL)cc2)cncc1

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

1.965 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value

Remarks:

imidazole class

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

20.931 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: QSAR predicted value

Remarks:

benzyl alcohol class

ECOSAR v1.11 predicted that the test item has a LC50 on daphnia = 1.965 mg/L (imidazole class); 20.931 mg/L (benzyl alcohol class).

Validity criteria fulfilled:

not applicable

Conclusions:

According to ECOSAR v1.11, the estimated 48 -h LC50 for Daphnia is 1.965 mg/l (ECOSAR v1.1, class: imidazoles).

Executive summary:

According to ECOSAR v1.11, the test item has an LC50 on daphnia = 1.965 mg/L (imidazole class) - 20.931 mg/L (benzyl alcohol class). The lowest value can be taken as a worst case scenario.

Description of key information

Weight of evidence. A study according to OECD TG 202 / EU Method C.2 (GLP study) is available. Based on the results obtained, the 48h EC50 value of the test item on Daphnia magna is 8.953 mg/L. Also, according to a calculation by ECOSAR v1.11 model, the 48h-LC50 of the test item on daphnia is 1.965 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

8.953 mg/L

Additional information

A short-term toxicity test on aquatic invertebrates was performed on the test item, according to OECD TG 202 / EU Method C.2, under GLP conditions. In accordance to a range-finding preliminary study, the nominal concentrations of test item used in the main experiment were:0.69; 1.38; 2.76; 5.52; 11.05; 22.10 and 44.20 mg/l (nominal). Twenty daphnids (< 24 h old, 5 per replicate) were exposed to either a control medium or the test item concentrations specified for 48 hours under static conditions. No analytical monitoring was performed. The validity criteria were fulfilled. Based on the results obtained, the 48h EC50 value of the test item on Daphnia magna is 8.953 mg/L. No NOEC value was obtained. Furthermore, according to a calculation by ECOSAR v1.11 model, the LC50 of the test item on daphniais 1.965 mg/L.