Reaction products of 1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-(C7 odd-numbered alkyl) derivs. and sodium hydroxide and chloroacetic acid

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The rationale to read across the data is attached in Section 13.

Reason / purpose for cross-reference:

exposure-related information

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

25.4 mg/L

Nominal / measured:

nominal

Conc. based on:

other: solid fraction

Basis for effect:

mobility

Details on results:

- Abnormalities observed: no
- After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the nominal test item concentration of 24.0 mg test item/L (9.4 mg solids/L). At the nominal concentration of 52.9 mg test item/L (20.7 mg solids/L), 7 animals were immobile and 18 animals were immobile at the nominal concentration of 116.2 mg test item/L (45.5 mg solids/L). At the highest test concentration of 255.4 mg test item/L (100 mg solids/L), 20 daphnids were immobile (see table 2).
- At test end, the test medium appeared to be slightly turbid at 116.2 mg test item/L (45.5 mg solids/L) and turbid at 255.4 mg test item/L (100 mg solids/L)
- The 95% confidence interval for the EC50 was calculated to be 52.7 -79.6 mg/L (20.6 -31.2 mg solids/L)
- Analysis showed that the test concentrations remained 84-100% of nominal test concentrations. Therefore, the effect concentrations were based on nominal test concentrations.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: 48h-EC50: 1.06 mg/L
- Other: based on the 24h-EC50 of 1.48 mg/L, the sensitivity was according to the proposed OECD levels (24h-EC50 between 0.6 and 2.1 mg potassium dichromate/L).

Reported statistics and error estimates:

The 24-hour and 48-hour EC50, EC20 and EC10 and the 95 % confidence limits were calculated by probit analysis.
The NOEC and LOEC after 24 and 48 hours were determined directly from the raw data.
The software used to perform the statistical analysis was ToxRat Professional, Version 3.2.1, ToxRat Solutions GmbH.

Table 1 Measured concentrations (data on source chemical)

Sample description			Concentration found	D.F.	Concentration calculated	Concentration nominal
(mg test item/L)	Sampling day	Age (h)	(mg test item/L)*	1	(mg test item/L)*	(mg test item/L)	% of nominal*
Control	0	0	<LOD	1	n.a.	0.000	n.a.
Control	0	0	<LOD	1	n.a.	0.000	n.a.
Control	2	48	<LOD	1	n.a.	0.000	n.a.
Control	2	48	<LOD	1	n.a.	0.000	n.a.
11	0	0	9.591	1	9.591	11.000	87
11	0	0	9.943	1	9.943	11.000	90
11	2	48	9.051	1	9.051	11.000	82
11	2	48	9.774	1	9.774	11.000	89
						Mean value (n=4):	87
						RSD (n=4):	4
24	0	0	20.932	1	20.932	2400	87
24	0	0	20.212	1	20.212	2400	84
24	2	48	19.591	1	19.591	2400	82
24	2	48	20.309	1	20.309	2400	85
						Mean value (n=4):	84
						RSD (n=4):	3
52.9	0	0	50.787	1	50.787	52.900	96
52.9	0	0	50.447	1	50.447	52.900	95
52.9	2	48	45.703	1	45.703	52.900	86
52.9	2	48	34.483	1	34.483	52.900	^#65
						Mean value (n=4):	93
						RSD (n=4):	6
116.2	0	0	116.167	1	116.167	116.200	100
116.2	0	0	117.555	1	117.555	116.200	101
116.2	2	48	117.310	1	117.310	116.200	101
116.2	2	48	115.433	1	115.433	116.200	99
						Mean value (n=4):	100
						RSD (n=4):	1
255.4	0	0	126.955	2	253.909	255.400	99
255.4	0	0	125.225	2	250.449	255.400	98
255.4	2	48	118.792	2	237.583	255.400	93
255.4	2	48	122.773	2	245.546	255.400	96
						Mean value (n=4):	97
						RSD (n=4):	3
					Overall mean value (n=20)		92
					RSD (n=20)		7

* The tabulated results represent rounded results calculated on the exact raw data

LOD: Limit of Detection = 1 mg test item/L

n.a.: not applicable; RSD: Relative Standard Deviation; D.F.: Dilution factor

^#considered to be an outlier, not used for calculation

Table 2 Influence of Miranol Ultra C32 on the mobility of Daphnia magna

Nominal concentration (mg test item/L)	No. of Daphnia tested	No. of immobilized Daphnia		% of immobilized Daphnia
		After 24 h	After 48 h	After 24 h	After 48 h
Control	20	0	0	0	0
11	20	0	0	0	0
24	20	0	0	0	0
52.9	20	1	7	5	35
116.2	20	2	18	10	90
255.4	20	1	20	5	100

Validity criteria fulfilled:

yes

Remarks:

See 'overall remarks' section

Conclusions:

The 48h-EC50 for Miranol Ultra C32 towards Daphnia magna was 64.8 mg/L (25.4 mg solids/L). This result is read across to C8 Amphoacetates (recalculated EC50 is 26.7 mg/L (25.4 mg solids/L).

Executive summary:

A short term toxicity test was performed, according to OECD guideline 202 and GLP principles, to assess the potential of Miranol Ultra C32 to induce immobility in Daphnia magna.The test item was corrected for the solid fraction and added to the medium at nominal concentrations of 11, 24, 52.9, 116.2 and 255.4 mg test item/L (corresponding to 4.3, 9.4, 20.7, 45.5 and 100 mg solids/L). Twenty daphnia per concentration and a blank control, divided over four vessels, were exposed to the test solutions for 48 hours. The number of immobilised daphnids after 24 hours and 48 hours was recorded. Duplicate samples for analysis were taken at t=0 and t=48 to determine actual exposure concentrations. Analysis showed that the test concentrations remained 84-100% of nominal test concentrations and thus the effect concentrations were based on nominal test concentrations.

In the lowest concentrations (11 and 24 mg/L) no daphnids became immobilised, while in the highest concentration all daphnids became immobilised. The 48h-EC50 of Miranol Ultra C32 was determined to be 64.8 mg/L (25.4 mg solids/L) with 95% confidence interval 52.7 -79.6 mg/L (20.6 -31.2 mg solids/L). All validity criteria were met and the study was considered to be valid. This result is read across to C8 Amphoacetates (recalculated EC50 is 26.7 mg/L (25.4 mg solids/L).

Description of key information

Two recent studies with two forms of an analogous substance (Amphoacetates C8 -C18, mono-acetate form and di-acetate form) are available. The EC50 values were found to be 25.4 mg solids/L and 56.7 mg solids/L. The results are read across, as explained in the read-across report attached in Section 13. The lowest EC50 value obtained (25.4 mg/L based on solid content, for the mono-acetate form) is used as a worst-case key value for chemical safety assessment.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

25.4 mg/L

Additional information

C8 -C18 mono-acetate:

EC50: 25.4 mg/L; NOEC 9.4 mg/L, based on analytically confirmed test substance corrected for water content (and specified in the report as “solids”).

C8 -C18 di-acetate:

EC50: 56.7 mg/L; NOEC 20.7 mg/L, based on analytically confirmed test substance corrected for water content (and specified in the report as “solids”).