Dioleamide

Short-term toxicity to aquatic invertebrates

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
In view of the difficulties associated with the evaluation of aquatic toxicity of poorly water soluble test items, a modification of the standard method for the preparation of aqueous media was performed. An approach endorsed by several important regulatory authorities in the EU and elsewhere (ECETOC 1996 and OECD 2000), is to expose organisms to a saturated solution of the test item in cases where the test item is of high purity and is poorly soluble in water and in the permitted auxiliary solvents and surfactants. Using this approach, a saturated solution was prepared by stirring an excess (50 mg/L) of test item in culture medium for a period of 24 hours prior to removing any undissolved test item present by filtration (0.2 μm Gelman Acrocap filter, first approximate 500 mL discarded in order to pre-condition the filter) to give a saturated solution of the test item.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: bred at testing facility
- Age at study initiation: < 24 h


BREEDING
- Breeding conditions: same as in test
- Type and amount of food: algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension.
- Feeding frequency: daily

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L

Test temperature:

20 - 22 °C

pH:

7.6 - 7.9

Dissolved oxygen:

8.6 - 9.7 mg/L

Nominal and measured concentrations:

Nominal test substance concentration: 10, 18, 32,56 and 100% v/v saturated solution

Details on test conditions:

TEST SYSTEM
- Test vessel: glass jars (250 mL nominal volume)
- Fill volume: 200 mL
- 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: Elendt M7 Medium
- Intervals of water quality measurement: at test start and test termination

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16:8 h day-night regime
- Light intensity: 648 - 660 lux

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

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 0.10, 1.0, 10 and 100% v/v saturated solution
- Results used to determine the conditions for the definitive study: Immobilization was observed at 100% v/v saturated solution

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: (% v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The test substance concentration was analysed for verification of test concentrations at 0 and 48 hours by HPLC-MS-MS (Perkin Elmer, API 3000; triple stage quadrupole mass spectrometer). The test concentrations were below the limit of quantitation (LOQ= 0.014 mg/L).

Results with reference substance (positive control):

EC50 (48 h): 0.45 mg/L

Any other information on results incl. tables

Cumulative Immobilization Data

Nominal concentration (% v/v saturated solution)	Immobilized Daphnia (mean)
	24 h	48 h
Control	0	0
10	0	0
18	0	0
32	0	0
56	0	0
100	0	2

(Initial population: 5 per replicate)

Whilst there was no immobilization in 20 daphnids exposed to test concentrations of 10, 18, 32 and 56% v/v saturated solution, 2 daphnia were observed to be immobilized in the 100% v/v saturated solution test concentration. However, as this is only 10% immobilization this is not thought to be a true toxic effect of this test item. Inspection of the immobilization data gave the following results:

Time (h) EC50 (% v/v saturated solution)

24 >100

48 >100

The No Observed Effect Concentration after 24 and 48 hours exposure was 100% v/v saturated solution.

Applicant's summary and conclusion

Executive summary:

The read across source substance did not show any toxicity at the saturation concentration. This experimental result confirms the QSAR prediction for the target substance also predicting no toxicity at the solubility limit.