Aluminium triethanolate

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

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control, 10, 18, 32, 56 and 100 mg/L nominal concentrations.
- Sampling method: Samples were taken from the freshly prepared control and each test group from the bulk test preparation at 0 and 24 hours and from the expired test media (pooled replicates) at 24 and 48 hours for quantitative analysis.
- Sample storage conditions before analysis: The 0 hour fresh and 48 hour expired test media were analyzed immediately while the 24 hour fresh and expired were stored frozen prior to analysis. Duplicate samples were taken at 0, 24 and 48 hours and stored frozen for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A nominal amount of test substance was dissolved in test water and the volume adjusted to give the 100 mg/L test concentration for which a series of dilutions were made to give further test concentrations. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity. As the substance was expected to hydrolyse rapidly with ethanol as a product, normal approaches for difficult test substances (e.g. WAFs) were not considered appropriate owing to the prolonged stirring time required.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone: Straus
- Age at study initiation (mean and range, SD): Less than 24 hours old
- Weight at study initiation (mean and range, SD): NA
- Length at study initiation (length definition, mean, range and SD): NA
- Stage and instar at study initiation: First instar
- Valve height at study initiation, for shell deposition study (mean and range, SD): NA
- Peripheral shell growth removed prior to test initiation: NA
- Method of breeding: In house laboratory cultures
- Source: In house laboratory cultures
- Age of parental stock (mean and range, SD): Not detailed
- Feeding during test: No

ACCLIMATION
- Acclimation period: Less than 24 hours old
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: Each culture was fed daily with a mixture of algal suspension (Raphidocelis subcapitata) and GEMMA Micro 300 fish food suspension. Culture conditions ensured that reproduction was by parthenogenesis.

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES, INCLUDING CULTURING CONDITIONS: Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Approximate theoretical hardness of 250 mg/L as CaCO3

Test temperature:

20 to 21°C

pH:

8.1 to 8.5 across all groups

Dissolved oxygen:

8.6 to 9.1 across all groups

Salinity:

NA

Conductivity:

NA

Nominal and measured concentrations:

Nominal: Control, 10, 18, 32, 56 and 100 mg/L
Measured: Not applicable for substance as such. Only aluminium concentrations and indication of ethanol concentration available.

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL glass vessels
- Type (delete if not applicable): open (with glass slip to limit evaporation)
- Material, size, headspace, fill volume: 150 mL vessels containing approximately 100 mL of test preparations.
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Standard as per OECD guidelines

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light 8 hours darkness
- Light intensity: 774 to 905 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mobility at 24 and 48 hours

VEHICLE CONTROL PERFORMED: No

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: Based on this information test concentrations of 10, 18, 32, 56 and 100 mg/L were selected for the definitive test.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (not run concurrently with test)

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:

Range finding test: No immobilization was observed at the test concentrations of 0.10, 1.0 and 10 mg/L, however; 100% immobilization was observed at 100 mg/L. Reduced mobility was observed at the 100 mg/L test concentrations. Based on this information test concentrations of 10, 18, 32, 56 and 100 mg/L were selected for the definitive test. Chemical analysis of the test preparations showed measured test concentrations of ethanol to range from 83 to 88 mg/L, 81 to 86 mg/L, 78 to 81 mg/L, 79 to 82 mg/L, 77 to 79 mg/L and 72 to 76 mg/L at 0, 1, 3, 5, 24 and 48 hours respectively. Measured test concentrations of aluminium ranged from less than the LOQ to 6.4 mg/L at 0 hours and from less than the LOQ to 0.65 mg/L at 48 hours. There was a significant decline in the measured concentrations over 48 hours indicating hydrolysis of the test item under test conditions. It was considered sufficient to perform analysis of the aluminium only for the definitive test.

Definitive test
Verification of test concentrations: Analysis of the test preparations at 0 hours showed measured test concentrations as aluminium to range from 0.31 to 2.0 mg/L. Analysis of the test preparations at 48 hours showed a decline in measured test concentrations as aluminium to range from 0.25 to 0.79 mg/L. Low levels of test item, 0.068 and 0.060 mg/L were detected in the control samples at 0 and 48 hours respectively. As the amounts detected were low this was considered not to have impacted on the study. The measured aluminium concentrations do not directly indicate the aluminium species present and in some cases are variable. The only aluminium source should be the parent substance with a good correlation between nominal 0 hour parent concentrations and the increase in aluminium content. Ethanol is also rapidly produced as a hydrolysis product as evidenced through trial work. Accordingly, based on the intrinsic properties of the substance, effect concentrations are based on nominal values.

Sublethal effects: Sub-lethal effects of exposure were observed in the control and test concentrations 10, 18, 32, and 100 mg/L. These responses were reduced mobility and pale appearance.

Validation criteria: The test was considered to be valid given that not more than 10% of the control daphnids of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Observations on test item solubility: At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Results with reference substance (positive control):

- Results with reference substance valid?
- Relevant effect levels: 48 hour EC50 0.71 mg/L (within normal range for this reference item (0.6 to 2.1 mg/L))

Reported statistics and error estimates:

The EC50 values and associated confidence limits at 24 and 48 hours and the slope of the response curve and its standard error were calculated by Probit analysis using Linear Maximum-Likelihood regression. The Lowest Observed Effect Concentration (LOEC) and the No Observed Effect Concentration (NOEC) at 24 hours were calculated using the Fisher’s Exact Binomial Test with Bonferroni correction. The NOEC and LOEC at 48 hours were calculated using Step-down Cochran-Armitage Test incorporating Tarone’s test. All results were calculated using the ToxRat Professional computer software package (TOXRAT).

Cumulative immobilization data and observations in the definitive test:

Nominal concentration (mg/L)	48 hours
	Cumulative immobilized Daphnia (initial 5 per replicate)						observations
	1	2	3	4	Total	%	1	2	3	4
Control	0	0	0	0	0	0	5N	1R 4N	5N	5N
10	0	0	0	0	0	0	5N	5N	5N	5N
18	1	0	0	1	2	10	1l 4N	5N	1R 4N	1I 4N
32	0	0	0	0	0	0	5N	5N	5N	5N
56	0	0	0	1	1	5	5N	5N	5N	1I 4N
100	2	0	2	4	8	40	3R 2I	1R 4N	3R 2I	1P 4I

N = Normal

R = Reduced mobility

P = Pale

I = immobilized

Analytical results for aluminium:

Time point	Nominal concentration (mg/L)	Sample dilution factor	Determined concentration of aluminium in test sample (mg/L Al)	Percentage of nominal concentration (%)
0	Control	1.02	< LOQ / 0.0679*	-
	10	1.02	0.311	-
	18	1.02	0.415	-
	32	2.04	0.700	-
	56	5.10	1.05	-
	100	10.2	1.97	-
P.Rec 1	0.1	1.02	0.101	101
P.Rec 2	0.1	1.02	0.101	101
	Control	1.02	0.0818 / 0.0598*	-
	10	1.02	0.255 / 0.253*	-
	18	1.02	0.314 / 0.347*	-
	32	2.04	0.492 / 0.433*	-
	56	5.10	< LOQ / 0.517*	-
	100	10.2	< LOQ / 0.790*	-
P.Rec 1	0.1	1.02	0.106 / 0.107*	106 / 107*
P.Rec 2	0.1	1.02	0.102 / 0.108*	102 / 108*

* = Frozen duplicate

LOQ = 0.053 mg/L

Ethanol analysis (range finder)

Time point (hours)	Measured concentration (mg/L) Ethanol
0	87.6
0	82.6
1	85.6
1	81.1
3	80.8
3	77.9
5	82.3
5	78.8
24	76.8
24	79.1
48	75.5
48	72.4

Validity criteria fulfilled:

yes

Conclusions:

Exposure of freshwater invertebrate Daphnia magna to the test item has been investigated and gave a 48 hour EC50 value of > 100 mg/L.

Description of key information

Exposure of freshwater invertebrate Daphnia magna to the test item has been investigated and gave a 48 hour EC50 value of > 100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L