2-ethylanthraquinone

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 12 February 2016 to 13 June 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

No hourly measurements of temperature for the first day (this deviation was considered to have had no adverse effect on the results of the test). On Day 16 in the 0.0058 and 0.052 mg/L test concentrations the dissolved oxygen concentration was measured as 2.6 and 2.7 mg O2/L respectively. As the deviation was only slightly outside of the recommended parameter range and did not coincide with any mortalities or sub-lethal effects, this was considered not to adversely affect the results of the test.

Deviations:

yes

Remarks:

This was considered not to adversely affect the results of the test.

Qualifier:

according to guideline

Guideline:

EU Method C.20 (Daphnia magna Reproduction Test)

Version / remarks:

No hourly measurements of temperature for the first day (this deviation was considered to have had no adverse effect on the results of the test). On Day 16 in the 0.0058 and 0.052 mg/L test concentrations the dissolved oxygen concentration was measured as 2.6 and 2.7 mg O2/L respectively. As the deviation was only slightly outside of the recommended parameter range and did not coincide with any mortalities or sub-lethal effects, this was considered not to adversely affect the results of the test.

Deviations:

yes

Remarks:

This was considered not to adversely affect the results of the test.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples of the fresh test preparations were taken from the bulk test preparations on Days 0, 5, 9, 14 and 19 and of the expired test preparations (replicates pooled) on Days 2, 7, 12, 16 and 21. Samples were stored frozen prior to analysis. Duplicate samples were taken and stored frozen for further analysis if necessary.

Vehicle:

yes

Remarks:

Dimethylformamide

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: dilution
- Chemical name of vehicle: Dimethylformamide
- Concentration of vehicle in test medium: volume adjusted to 10 mL to give a 2.0 mg/mL stock solution.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Age: less than 24 hours old.
- Feeding during test: yes
- Food type: algal suspension (Desmodesmus subspicatus) and flake food suspension
- Frequency: daily

ACCLIMATION - parental stock
- Temperature: approximately 20 °C
- Photoperiod: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods
- Food type: algal suspension (Desmodesmus subspicatus) and flake food suspension
- Frequency: daily

Test type:

not specified

Water media type:

other: The reconstituted water (Elendt M7 medium)

Limit test:

no

Total exposure duration:

21 d

Hardness:

246 to 284 mg/L as CaCO3

Test temperature:

20 °C to 22 °C

pH:

7.5 to 8.1
Variation: 0.6

Dissolved oxygen:

≥7.9 mg O2/L

Nominal and measured concentrations:

Nominal test concentrations: 0.00512, 0.0128, 0.032, 0.080 and 0.20 mg/L
Time weighted mean measured test concentration: 0.0028, 0.0058, 0.021, 0.052 and 0.14 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass vessels
- Material, size, headspace, fill volume: 100 mL
- Aeration: covered with a plastic lid to reduce evaporation
- Renewal rate of test solution: Days 3, 5, 7, 10, 12, 14, 17 and 19
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Biomass loading rate: approximately 0.1 to 0.2 mg carbon/daphnid/day

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: nominal concentrations of 0.010, 0.030, 0.10 and 0.30 mg/L
- Results used to determine the conditions for the definitive study: No significant immobilization was observed at the test concentrations of 0.010, 0.030 and 0.10 mg/L; significant immobilization was observed at 0.30 mg/L; Sub-lethal effects of exposure were observed at test concentrations of 0.10 mg/L and above.

Reference substance (positive control):

not specified

Key result

Duration:

21 h

Dose descriptor:

EC50

Effect conc.:

0.033 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other:

Remarks:

Table 1

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.006 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other:

Remarks:

Table 1

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.021 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other:

Remarks:

Table 1

Key result

Duration:

21 d

Dose descriptor:

EC10

Effect conc.:

0.045 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

Table 2

Key result

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

0.064 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

Table 2

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.021 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

Table 2

Key result

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.052 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other:

Remarks:

Table 2

Details on results:

Immobilization:
Statistical analysis of the mortality data using the Step-down Cochran-Armitage test showed that the observed mortalities in the test groups were not significantly different (P≥0.05) when compared to the control group and are therefore considered to be inadvertent mortalities.

Sub-lethal Effects on the Parental Generation (P1):
Statistical analysis showed there was no significant difference in the body length of surviving parent daphnia identified between the control and solvent control groups.
There was a statistically significant difference (P≥ 0.05) between the control the 0.052 mg/L test group in terms of length of the daphnids after 21 days exposure to the test item.

Reproduction:
After 21 days there were no statistically significant differences between the solvent control and the 0.0028, 0.0058 and 0.021 mg/L test groups in terms of the number of live young produced per adult.
The 0.052 and 0.14 mg/L test groups showed a statistically significant difference from the solvent control after 21 days in terms of producing fewer numbers of live young per adult.

Reported statistics and error estimates:

Statistical analysis of the mortality data using the Step-down Cochran-Armitage test showed that the observed mortalities in these test groups were not significantly different (P≥0.05) when compared to the control group and are therefore considered to be inadvertent mortalities.

Table 1: Immobilisation

Endpoint		Concentration (mg/L)
Immobilization	EC50	0.033
	95% confidence limits	0.0028 – 0.14
No Observed Effect Concentration (NOEC)		0.0058
Lowest Observed Effect Concentration (LOEC)		0.021

Table 2: Reproduction

Endpoint		Concentration (mg/L)
Reproduction	EC10	0.045
	95% confidence limits	0.019 – 0.11
	EC50	0.064
	95% confidence limits	0.0073 – 0.53
No Observed Effect Concentration (NOEC)		0.021
Lowest Observed Effect Concentration (LOEC)		0.052

Validity criteria fulfilled:

yes

Conclusions:

Exposure of Daphnia magna to the test item resulted in significant mortalities at the time weighted mean measured test concentrations of 0.021, 0.052 and 0.14 mg/L.
The 21-Day EC50 (immobilization) value, based on time-weighted mean measured concentrations, for the parental daphnia generation (P1) was calculated to be 0.033 mg/L with 95% confidence limits of 0.0028 to 0.14 mg/L.
The 21-Day EC10 and EC50 (reproduction) values, based on time-weighted mean measured concentrations were calculated to be 0.045 mg/L and 0.064 mg/L respectively with 95% confidence limits for the EC50 of 0.0073 to 0.53 mg/L.
The "Lowest Observed Effect Concentration" (LOEC) and the "No Observed Effect Concentration" (NOEC) based on time-weighted mean measured concentrations determined for parental generation immobilizations were 0.021 and 0.0058 mg/L respectively.

Executive summary:

The chronic toxicity of the test item to Daphnia magna was investigated in accordance with OECD TGD (2012).

Ten replicates of a single daphnid per group were exposed to solutions of the test item at nominal concentrations of 0.00512, 0.0128, 0.032, 0.080 and 0.20 mg/L for a period of 21 days. The numbers of live and dead adult daphnia and young daphnids (live and dead) were determined daily.

Analysis of the fresh test preparations on Days 0, 5, 9, 14 and 19 showed measured test concentrations to range from less than the Limit of Quantification (LOQ) of the analytical method which was determined to be 0.0056 mg/L, to 0.147 mg/L. Analysis of the aged test preparations on Days 2, 7, 12, 16 and 21 showed a decline in measured concentrations after each exposure period range from less than the LOQ to 0.133 mg/L and hence it was considered appropriate to calculate the results based on the time- weighted mean measured test concentrations in order to give a “worst case” analysis of the data.

 

Exposure of Daphnia magna to the test item resulted in an EC50 values of 0.033 mg/L for immobilisation and 0.064 mg/L for reproduction. The NOEC was 0.0058 mg/L for immobilisation and 0.021 mg/L for reproduction. 

Description of key information

Exposure of Daphnia magna to the test item resulted in significant mortalities at the time weighted mean measured test concentrations of 0.021, 0.052 and 0.14 mg/L.

The 21-Day EC50 (immobilization) value, based on time-weighted mean measured concentrations, for the parental daphnia generation (P1) was calculated to be 0.033 mg/L with 95% confidence limits of 0.0028 to 0.14 mg/L

The 21-Day EC10 and EC50 (reproduction) values, based on time-weighted mean measured concentrations were calculated to be 0.045 mg/L and 0.064 mg/L respectively with 95% confidence limits for the EC50 of 0.0073 to 0.53 mg/L.

The "Lowest Observed Effect Concentration" (LOEC) and the "No Observed Effect Concentration" (NOEC) based on time-weighted mean measured concentrations determined for parental generation immobilizations were 0.021 and 0.0058 mg/L respectively.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.006 mg/L

Additional information

Table 1: Immobilization

Endpoint		Concentration (mg/L)
Immobilization	EC50	0.033
	95% confidence limits	0.0028 – 0.14
No Observed Effect Concentration (NOEC)		0.0058
Lowest Observed Effect Concentration (LOEC)		0.021

Table 2: Reproduction

Endpoint		Concentration (mg/L)
Reproduction	EC10	0.045
	95% confidence limits	0.019 – 0.11
	EC50	0.064
	95% confidence limits	0.0073 – 0.53
No Observed Effect Concentration (NOEC)		0.021
Lowest Observed Effect Concentration (LOEC)		0.052