Azelaic acid, calcium salt (1:1)

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is carried out in accordance to OECD guideline 202 and is GLP compliant.

Justification for type of information:

Please see attached read across justification for full details of the read across approach.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

In the range-finding test the Total Organic Carbon concentration was determined with the TOC instead of NPOC method. As this is an equivalent alternative it was not considered to affect the outcome of the test.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

In the range-finding test the Total Organic Carbon concentration was determined with the TOC instead of NPOC method. As this is an equivalent alternative it was not considered to affect the outcome of the test.

Principles of method if other than guideline:

Combined limit/range finding study.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: A058/99
- Expiration date of the lot/batch: 6 March 2018
- Purity test date: Not specified

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature protected from light
- Stability under test conditions: Not specified
- Solubility and stability of the test substance in the solvent/vehicle: Not applicable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: Not applicable

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None
- Preliminary purification step (if any): None
- Final dilution of a dissolved solid, stock liquid or gel: None
- Final preparation of a solid: None

Analytical monitoring:

yes

Details on sampling:

The confirmatory chemical analysis was based on the concentration of the fatty acid component (azelate) and on the concentration of the lithium ion. The concentration of total organic carbon (TOC) was also measured.
Samples for analysis were taken from the control and the 100 mg/L treatment at the start of the test and after 48 hours of exposure and stored in a refrigerator (TOC) or freezer (lithium and azelate) until analysis.
For the determination of the test substance based on azelate, the samples were diluted in a 1:1 (v:v) ratio with 2% formic acid in acetonitrile and analysed. If necessary, the samples were further diluted with 1% formic acid in 50/50 (v/v) acetonitrile/ISO-medium to obtain concentrations within the calibration range.
For the determination of the test substance based on lithium, the samples were diluted in a 24:1 (v:v) ratio with HNO3 and analysed. If necessary, the samples were further diluted with 4% HNO3 in ISO-medium to obtain concentrations within the calibration range.

Vehicle:

no

Details on test solutions:

Nominal concentrations: 0.10, 1.0, 10 and 100 mg/L
Medium: Adjusted ISO medium
Solubility: The test item was completely soluble in test medium at the concentrations tested.
Preparation of test solutions: A solution with a concentration of 100 mg/L with vigorous shaking. The lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium.
Appearance: The final test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

Source: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions from an in-house laboratory culture with a known history.
Batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress.
Age: Young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

Not reported. Breeding water: 180 mg CaCO3/L

Test temperature:

20-21°C

pH:

pH 7.8-8.0

Dissolved oxygen:

8.9-9.0 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0.1, 1, 10 and 100 mg/L.
The measured concentrations based on azelate were at the level of 91-93% of nominal during the exposure period.
The measured concentrations based on lithium were at the level of 99-101% of nominal during the exposure period.
The measured concentrations at 0h were 0.065 and 56 mg TOC/L and at 48h they were 0.17 and 55 mg TOC/L for the control and the highest concentration respectively. The TOC remained relatively stable throughout the test.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL
- Material, fill volume: Glass, 80 mL
- Aeration: No aeration of test solutions
- No. of organisms per vessel: 5
- No. of daphnids per concentration: 20 for control and limit concentration, 10 for lower concentrations
-Introduction of daphnids: Within 39 minutes of preparation of the test solutions
OTHER TEST CONDITIONS
- Photoperiod: 16 hours
- Feeding: No feeding

Reference substance (positive control):

yes

Remarks:

potassium dichromate (K2Cr2O7)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The 48h-EC50 exceeded the nominal concentration of 100 mg/L.

Results with reference substance (positive control):

The actual responses in this reference test with K2Cr2O7 are within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.3 and 1.0 mg/L. Hence, the sensitivity of the Daphnia was within the range determined with the historical data collected at WIL Research Europe.

Reported statistics and error estimates:

Not reported.

Time (h)	Replicate	Nominal concentration Dilithium azelate (mg/L)
		Control	0.10	1.0	10	100
0	A	5	5	5	5	5
	B	5	5	5	5	5
	C	5				5
	D	5				5
	Total introduced	20	10	10	10	20
24	A	0 (1)	0	0	0	0
	B	0	0	0	0	0
	C	0				0
	D	0				1
	Total immobilised	0	0	0	0	1
	Effect %	0	0	0	0	5
48	A	0	0	0	0	0
	B	0	0	0	0	0
	C	1				0
	D	0				1
	Total immobilised	1	0	0	0	1
	Effect %	5	0	0	0	5

Parameter	Nominal concentration Dilithium azelate (mg/L)
24-48h-EC50	>100

Concentration K2Cr2O7 (mg/L)		Number Exposed	% immobile		Expected response (%) After 48 hours^1
			24h	48h	Minimal	Maximal
control	20		0	0	0	10^2
0.10	20		0	0	0	10
0.18	20		0	0	0	10
0.32	20		0	10	0	30
0.56	20		10	100	0	100
1.0	20		95	100	40	100
1.8	20		100	100	100	100

( ) between brackets: number of Daphnia observed trapped at the surface of the test solutions. This organism was reimmersed into the respective solution before recording of mobility.

1 – Based on historical data of the previous years (n>60).

2 – A maximum response of 10% does not invalidate the results of the test.

Validity criteria fulfilled:

yes

Conclusions:

No EC50 could be calculated because the test substance did not cause a significant difference to the mobility of the Daphnia magna (EC50 > 100 mg/L, the maximum concentration tested).

Executive summary:

The effect of dilithium azelate on the mobility of the Daphnia Magna was investigated according to an OECD 202 guideline and EC method C2.  A 48 hour combined range finder / limit test was conducted at 0.1, 1, 10 and 100 mg/L under static conditions. At the start of the test all solutions were clear and colourless. Analysis of the fatty acid (azelate) was between 91 and 93% nominal and the lithium concentration was between 99 and 101% of nominal throughout the test. The total organic carbon (TOC) measured at the start of the test was 56 mg/L and at the end of the test was 55 mg/L for the highest test concentration. The test concentrations were considered to be maintained and the results are reported based on nominal concentrations. The study met all the validity criteria for the test. As no effects on the mobility of Daphnia Magna were observed in the test the EC50 is > 100 mg/L dilthium azelate.

Description of key information

Calcium azelate is considered not toxic to aquatic invertebrates based on data read across from the structural analogue, dilithium azelate. No EC50 could be calculated because the test substance did not cause a significant effect on the mobility of the Daphnia magna (EC50 > 100 mg/L, the maximum concentration tested).

Additional information

Data to assess the toxicity of calcium azelate to aquatic invertebrates has been read across from the structural analogue dilithium azelate. The effect of dilithium azelate on the mobility of the Daphnia magna was investigated according to an OECD 202 guideline in a 48 hour combined range finder / limit test at 0.1, 1, 10 and 100 mg/L under static conditions (Tabor-Kaplon 2015). At the start of the test all solutions were clear and colourless. The test concentrations were considered to be maintained, with analysis of the azelate being between 91 and 93% nominal and the lithium concentration between 99 and 101% of nominal throughout the test. The total organic carbon (TOC) was measured in the highest test concentration (start of the test 56 mg/L and end of the test 55 mg/L). The test results are reported based on nominal concentrations and, as no effects on the mobility of Daphnia magna were observed, the EC50 is > 100 mg/L.