2-(cyclohexylamino)ethanesulphonic acid

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:

2017-01-10 to 2017-10-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 13th April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

May 30, 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L

- Sampling method: Four replicate samples were taken from the test solution and one from the control solution both at the start and at the end of the experiment. The samples were diluted with the eluent in two consecutive steps. In the second step 0.5 mL of Internal Standard Work Solution was added before the solution was filled up to volume. Then samples were analysed with LC/MS/MS applying MRM assay.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The test solution used in the test was prepared by mechanical dispersion. An amount of 0.03 g test item was dissolved in 300 mL dilution water (ISO medium) in order to obtain the concentration of 100 mg/L. The test solution was freshly prepared in the testing laboratory just before introduction of test animals (start of the experiment).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus
- Source: Laboratory of Hydrobiology, 2100 Gödöllö, Kotlan S. u. 3, Hungary
- Feeding during test: no

ACCLIMATION
Test animals were bred under similar (or the same) conditions as that used during the exposure period (holding water, temperature, background colour etc.), therefore additional acclimatization before the test was not necessary. Brood daphnids were maintained in dilution water at the test temperature for at least 48 hours prior to the start of the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

249 mg/L (as CaCO3)

Test temperature:

19.8 - 20.1 °C

pH:

7.75 - 8.12

Dissolved oxygen:

7.24 - 8.15 mg/L

Salinity:

not applicable

Conductivity:

not applicable

Nominal and measured concentrations:

Nominal concentration: 100 mg/L
Measured concentration: Concentrations reported as nominal as recovery was 100 - 104 %

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beaker
- Type: open
- Fill volume: 40 mL
- Aeration: none
- 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: reconstituted water (ISO medium acc. to OECD TG 202)

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light and 8 hours darkness

EFFECT PARAMETERS MEASURED: immobilisation at 24 and 48 h

RANGE-FINDING STUDY
- Test concentrations: 0.01, 0.1, 1, 1 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

There was no immobilisation observed in the control and in the 100 mg/L concentration group.
In both groups no abnormal behaviour or appearance of test animals was noted.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
24-h EC50: 1.57 mg/L, (95 % confidence limits: 1.31 – 1.79 mg/L)
- Limit test: no
- Dose-response test: yes

Validity of the Study

Immobilisation was not observed 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 in all cases. All validity criteria were within acceptable limits and therefore the study was considered as valid.

Table 1: Summary of the Biological Endpoints

Parameter	Concentration [mg/L] based on nominal concentration
48 h-EC50 95 % conf. limits	> 100 not calculated
48 h-NOEC	100
48 h-LOEC	> 100

 

Analytical Results

A concentration of 100 mg/L (limit concentration) and a concurrent control was tested in the main test. The concentration of the test item was analytically determined at the start and at the end of the experiment. The test item was not detected in the untreated control group. In the treated group measured concentrations of the test item were 97 % of the nominal at the start and 103 % at the end of the test. Since the measured test item concentration remained within ± 20 % of the nominal during the test period of 48 hours, the biological results are given at nominal concentration.

Table 2. Test item’s concentrations measured in the test solutions

Nominal Concentration (mg/L)	Measured concentrations (mg/L)	In percentage of the nominal	Measured concentrations (mg/L)	In percentage of the nominal
100	98.7	99%	102.0	102%
	94.2	94%	102.5	102%
	97.0	97%	102.1	102%
	96.4	96%	104.7	105%
Mean with 95% confidence interval (mg/L)	96.6 ± 2.9	97%	102.8 ± 2.0	103%

 

Biological Results

There was no immobilisation observed in the control and in the 100 mg/L concentration group. In both groups no abnormal behaviour or appearance of test animals was noted. The 48-h NOEC was determined to be 100 mg/L. The 48-h LOEC and the EC₅₀ values were determined to be > 100 mg/L.

Table 3: Immobilization of the test animals

Test Group	Replicate	Number of treated animals	Number of immobilised animals
			24h	48h
Control	1	5	0	0
	2	5	0	0
	3	5	0	0
	4	5	0	0
100 mg/L	1	5	0	0
	2	5	0	0
	3	5	0	0
	4	5	0	0

 

Validity criteria fulfilled:

yes

Conclusions:

In a GLP-study according to OECD test guideline 202 the test item did show no toxicity to Daphnia magna at the limit test concentration of 100 mg/L. Therefore, the 48-h NOEC was determined to be 100 mg/L and the LOEC and the EC50 values were determined to be > 100 mg/L.

Executive summary:

The aquatic toxicity of the test item was assessed using Daphnia magna in a 48-h Acute Immobilisation Test according to OECD TG 202. For this purpose, young Daphnia were exposed to aqueous test media containing the test item for 48 hours. Based on results obtained in a non-GLP preliminary experiment Daphnia were exposed to a single concentration of 100 mg/L (limit concentration). The reference item potassium dichromate served as the reference control. A static test was performed as the test item was previously shown to be stable in the test medium for 48 hours. The purpose of the analytical part of this study was to verify the concentration of the test item in the test medium. The analytically measured test item concentration remained within ± 20 % of the nominal concentration during the test period of 48 hours; therefore, biological results are based on the nominal concentration. Healthy, young female daphnids with known origin, history and acclimatization conditions were used. The test item and the control were tested using 20 Daphnia (divided into 4 concurrent subgroups) each. Each test vessel contained approximately 50 mL test medium. The immobilisation of the test animals was recorded at 24 and 48 hours after treatment. Environmental conditions were recorded. All measured values remained within acceptable ranges. All validity criteria were met and therefore the study was considered as valid. Under the test conditions, the test item did show no toxicity to Daphnia magna at the limit test concentration of 100 mg/L. Therefore, the 48-h NOEC was determined to be 100 mg/L and the LOEC and the EC₅₀ values were determined to be > 100 mg/L.

Description of key information

In a GLP-study according to OECD test guideline 202 the test item did show no toxicity to Daphnia magna at the limit test concentration of 100 mg/L. Therefore, the 48-h NOEC was determined to be 100 mg/L and the LOEC and the EC₅₀ values were determined to be > 100 mg/L (reference 6.1.3-1).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The aquatic toxicity of the test item was assessed using Daphnia magna in a 48-h Acute Immobilisation Test according to OECD TG 202. For this purpose, young Daphnia were exposed to aqueous test media containing the test item for 48 hours. Based on results obtained in a non-GLP preliminary experiment Daphnia were exposed to a single concentration of 100 mg/L (limit concentration). The reference item potassium dichromate served as the reference control. A static test was performed as the test item was previously shown to be stable in the test medium for 48 hours. The purpose of the analytical part of this study was to verify the concentration of the test item in the test medium. The analytically measured test item concentration remained within ± 20 % of the nominal concentration during the test period of 48 hours; therefore, biological results are based on the nominal concentration. Healthy, young female daphnids with known origin, history and acclimatization conditions were used. The test item and the control were tested using 20 Daphnia (divided into 4 concurrent subgroups) each. Each test vessel contained approximately 50 mL test medium. The immobilisation of the test animals was recorded at 24 and 48 hours after treatment. Environmental conditions were recorded. All measured values remained within acceptable ranges. All validity criteria were met and therefore the study was considered as valid. Under the test conditions, the test item did show no toxicity to Daphnia magna at the limit test concentration of 100 mg/L. Therefore, the 48-h NOEC was determined to be 100 mg/L and the LOEC and the EC₅₀ values were determined to be > 100 mg/L.