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

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish early-life stage toxicity

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:

read-across source

Key result

Duration:

8 d

Dose descriptor:

EC10

Effect conc.:

> 1.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

number hatched

Remarks:

Embryonic survival

Key result

Duration:

33 d

Dose descriptor:

EC10

Effect conc.:

> 1.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

adult mortality

Remarks:

Post-hatch mortality

Key result

Duration:

33 d

Dose descriptor:

NOEC

Effect conc.:

0.61 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

morphology

Remarks:

Malformation of caudal fin

Key result

Duration:

33 d

Dose descriptor:

NOEC

Effect conc.:

0.61 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

other: Growth based on length and weight

Key result

Duration:

33 d

Dose descriptor:

EC10

Effect conc.:

0.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

weight

Remarks on result:

other: 95% confidence interval: 0.46 - 1.0 mg solids/L

Key result

Duration:

33 d

Dose descriptor:

EC10

Effect conc.:

0.79 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: Test substance corrected for water content (specified in report as "solids")

Basis for effect:

length

Remarks on result:

other: 95% confidence interval: 0.64 - 1.0 mg solids/L

Details on results:

- Measured concentrations: Analyses of samples taken at the start of the test showed that the measured concentrations were generally in agreement with the target concentrations, i.e. were at 97-119% relative to the target concentrations. The analyses of the samples taken on Days 7 to 33 showed lower measured concentrations ranging at 35-131% relative to the target concentrations. Consequently, samples taken from the stock solutions were taken on Days 14, 21, 28 and 33. The concentrations measured in these samples were at 94-126% of the expected concentrations and thus indicated proper preparation of stock solutions. The reason for the lower measured concentrations is not known, but the observed build-up of microbial biomass could be responsible for this. The effect parameters were thus based on mean measured concentrations, see Table 1 in 'Any other information on results'. It should be noted that small responses were measured in the samples taken from the control group. Those were, however, at the level of the observed carry-over within the analytical system and thus judged to not originate from a contamination of the control group.

- See Table 3 in 'Any other information on results' for all effect parameters.

- Embryonic survival: 99% survival in control. Hatching started on Day 3 and was completed by Day 8 of exposure. Hatchability ranged from 90 to 100% and was generally not treatment related. On Day 5, the percentage of hatching was higher in the test item treated groups than in the control treatment.

- Larval survival and development: 94% larval survival in control. Post-hatch mortality at the end of the test in test item treated groups ranged from 5 to 16% and was not concentration-related. Statistical analyses confirmed that larval survival was not significantly affected up to and including 1.6 mg solids/L (NOEC). In the highest test concentration, all larvae showed malformation of the caudal fin, first observed at day 19 (pictures of the malformations compared with the control larvae are in the attached illustration). At lower test concentrations, a number of larvae showed abnormalities of the skeleton, the eyes or the swim bladder. Other individuals showed changes of coloration, or yolk-sac or cardiac oedemas. These observations were however singular and not test item related.

- Effects on larval growth: The test item caused a dose-related reduction in both body weight and length. At the highest concentration, the reduction of weight reached 38% while length was reduced by 18%. Statistically significant reduction of body weight as well as body length was observed at 1.6 mg solids/L. Hence, the NOEC for growth was 0.61 mg solids/L based on body weight as well as based on body length.

- All environmental paramenters remained within the limits prescribed by the study plan throughout the test.

Reported statistics and error estimates:

Hatchability (embryonic survival):
- ECx values could not be calculated as ≥94% embryos hatched in all treatments.
- Differences between treatments and the control (Day 7): Chi²-2 x 2 table test with Bonferroni Correction (α=0.05, one-sided greater) after qualitative trend analysis by contrasts (monotonicity of concentration/response).

Larval survival:
- ECx values could not be calculated as ≤10% larvae died in any of the test concentrations compared to the control group.
- Differences between treatments and the control: Chi²-2 x 2 table test with Bonferroni Correction (α=0.05, one-sided greater) after qualitative trend analysis by contrasts (monotonicity of concentration/response).

Body length and body weight:
- ECx values: Probit analysis.
- Data distribution: Shapiro-Wilk´s Test
- Homogeneity of variance: Levene´s Test (with Residuals)
- NOEC: Williams Multiple Sequential t-test Procedure (α=0.05, one-sided smaller) after trend analysis by contrasts (monotonicity of concentration/response).

All analyses were performed with ToxRat Professional 3.2.1 (ToxRat Solutions® GmbH, Germany).

Table 1: Target, Measured and Mean Measured Concentrations During the ELS Test

 

Target conc.  (mg solids/L)	Measured concentration (mg solids/L)						Mean measured conc.(mg solids/L)
	Day 0	Day 7	Day 14	Day 21	Day 28	Day 33
0.050	0.058	0.034	0.039	0.029	0.020	0.031	0.035
0.013	0.14	0.098	0.10	0.069	0.070	0.061	0.090
0.31	0.34	0.25	0.28	0.15	0.18	0.15	0.22
0.78	0.76	0.60	0.50	0.48	0.27	1.0	0.61
2.0	2.4	1.7	1.6	1.6	1.4	1.2	1.6

Table 2: Survival of Fish Embryos and Larvae During the Range-Finding Test

Target concentrations (mg solids/L)	No. of eggs Day 0	Number of survivors (at nominal day)							Total survival (%)
		1	2	3	4	5	6	7
Control	10	10	10	10	10	10	10	10	100
	10	10	10	10	10	10	10	10	100
0.05	10	10	10	10	10	10	10	10	100
	10	9	9	9	9	9	9	9	90
0.50	10	9	9	9	8	8	8	8	80
	10	10	10	10	10	10	10	10	100
5.0	10	7	6	6	6	6	3	2	20
	10	7	6	6	6	5	1	1	10

 

Table 3: Effect parameters (mg solids/L)

 

Parameter		Mean measured concentration (mg solids/L)
		LOEC	NOEC	EC10	EC50
Embryonic survival	Value^(a)	>1.6	≥1.6	>1.6	>1.6
Post-hatch survival	Value^(b)	>1.6	≥1.6	>1.6	>1.6
Malformation of caudal fin	Value^(b)	1.6	0.61	n.a.	n.a.
Growth (weight)	Value^(b)	1.6	0.61	0.80	>1.6
	lower 95%-cl			0.46	*
	upper 95%-cl			1.0	*
Growth (length)	Value^(b)	1.6	0.61	0.79	>1.6
	lower 95%-cl			0.64	*
	upper 95%-cl			1.0	*

^(a)for Day 8 of exposure,^(b)for Day 33 of exposure, cl: confidence limit, * no confidence intervals could be determined, n.a. – not applicable

Table 4: Percentage of Embryonic Survival at the End of Hatching (Day 8)

 

Mean measured concentration (mg solids/L)	Total Introduced	Hatched	Not Hatched	% Hatched
Control	80	79	1	99
0.035	80	80	0	100
0.090	80	75	5	94
0.22	80	80	0	100
0.61	80	76	4	95
1.6	80	76	4	95

Table 5: Post-Hatch Mortalityat the End of Exposure (Day 33)

 

Mean measured concentration (mg solids/L)	Total^* introduced	Survived	Dead	% Post-hatch mortality
Control	79	74	5	6
0.035	80	67	13	16
0.090	75	71	4	5
0.22	80	72	8	10
0.61	76	67	9	12
1.6	76	66	10	13

^*Total number of hatched larvae.

Table 6: Mean Body Weight and Body Weight Reduction atthe End of Exposure (day 33)

 

Mean measured concentration (mg solids/L)	Mean	Std. Dev.	n	%Reduction
Control	74.450	5.7356	4
0.035	73.850	4.9776	4	0.81
0.090	76.550	2.0469	4	-2.8
0.22	69.150	4.6658	4	7.1
0.61	74.475	8.9481	4	-0.034
1.6	46.025	4.9026	4	38 *

* effect statistically significant

Table 7: Mean Body Length and Body Length Reduction atthe End of Exposure (Day 33)

 

Mean measured concentration (mg solids/L)	Mean	Std. Dev.	n	%Reduction
Control	21.21	0.395	4
0.035	21.29	0.335	4	-0.38
0.090	21.43	0.326	4	-1.0
0.22	20.48	0.268	4	3.5
0.61	21.26	0.826	4	-0.26
1.6	17.50	0.709	4	18 *

* effect statistically significant

Validity criteria fulfilled:

yes

Remarks:

See 'Overall remarks' for details on validity criteria.

Conclusions:

In a flow-through fish eary-life stage study with Amphoacetates C8-C18 (mono-acetate form), embryonic and larval survival was not affected at concentrations up to and including 1.6 mg solids/L; EC10 values were >1.6 mg solids/L. Consistent malformations of the caudal fin were observed in the highest test concentration of 1.6 mg solids/L, and thus the NOEC was considered to be 0.61 mg solids/L. EC10 values for growth reduction based on weight and length were 0.80 and 0.79 mg solids/L, respectively. The NOEC based on weight and length was 0.61 mg solids/L. This result is read across to the registered substance.

Executive summary:

A flow-through fish early-life stage toxicity test was performed in order to assess possible lethal and sub-lethal effects of Amphoacetates 8 -C18 (mono-acetate form) during the embryonic and early larval development of the fathead minnow (Pimephales promelas). The test item was a clear light yellow viscous liquid UVCB substance consisting of 39.6% solids in water. A correction factor of 2.525 was used to correct for the water content of the test item. Concentrations are expressed based on solids.

The study was conducted in accordance with OECD 210 and in compliance with GLP. Fertilized eggs were exposed to an untreated control and the test item at mean measured concentrations of 0.035, 0.090, 0.22, 0.61 and 1.6 mg solids/L (80 eggs per group, divided into four replicates).

Embryonic and larval survival was not affected at concentrations up to and including 1.6 mg solids/L; EC10 values were >1.6 mg solids/L. Consistent malformations of the caudal fin were observed in the highest test concentration of 1.6 mg solids/L, and thus the NOEC was considered to be 0.61 mg solids/L. EC10 values for growth reduction based on weight and length were 0.80 and 0.79 mg solids/L, respectively. The NOEC based on weight and length was 0.61 mg solids/L. This result is read across to the registered substance.

The study met all validity criteria and is considered valid without restriction.

Description of key information

A flow-through fish early-life stage toxicity test was performed with a chemical analogue of the registered substance in order to assess possible lethal and sub-lethal effects during the embryonic and early larval development of the fathead minnow (Pimephales promelas). The test item was a clear light yellow viscous liquid UVCB substance consisting of 39.6% solids in water. A correction factor of 2.525 was used to correct for the water content of the test item. Concentrations are expressed based on solids.

The study was conducted in accordance with OECD 210 and in compliance with GLP. Fertilized eggs were exposed to an untreated control and the test item at mean measured concentrations of 0.035, 0.090, 0.22, 0.61 and 1.6 mg solids/L (80 eggs per group, divided into four replicates).

Embryonic and larval survival was not affected at concentrations up to and including 1.6 mg solids/L; EC10 values were >1.6 mg solids/L. Consistent malformations of the caudal fin were observed in the highest test concentration of 1.6 mg solids/L, and thus the NOEC was considered to be 0.61 mg solids/L. EC10 values for growth reduction based on weight and length were 0.80 and 0.79 mg solids/L, respectively. The NOEC for weight and length was 0.61 mg solids/L. This result is read across to the registered substance.

The study met all validity criteria and is considered valid without restriction.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.61 mg/L

Additional information

In the flow-through fish early-life stage toxicity test performed with a chemical analogue of the registered substance consistent malformations of the caudal fin were observed in the highest test concentration of 1.6 mg solids/L, and thus the NOEC was considered to be 0.61 mg solids/L. EC10 values for growth reduction based on weight and length were 0.80 and 0.79 mg solids/L, respectively. The NOEC for weight and length was 0.61 mg solids/L, based on analytically confirmed test substance corrected for water content (and specified in the report as “solids”). The NOEC based on malformations (0.61 mg solids/L) is read across and used as worst-case key value for chemical safety assessment.