LUMIPOD

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:

31 July 2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not applicable

GLP compliance:

no

Remarks:

OECD 211 test GLP is in progress

Analytical monitoring:

yes

Remarks:

An organic carbon measurement was performed for the stock solution and two test concentrations in order to estimate the amount of test element present in the test solutions and its stability throughout the period of time exposure.

Details on sampling:

The test element considered to be slightly soluble in water, solubilization tests were carried out in order to optimize the dissolution.
These tests were carried out in different media (ultrapure water, daphnia test media) and the solubilization rate was estimated on the amount of organic carbon measured in the aqueous phase.
The various tests carried out to solubilize the test item showed very similar results.
Indeed, whatever the stirring time, the test medium used, the percentage of solubilized organic carbon was between 75 and 78% compared to the carbon content measured in the test item.
At the highest concentration tested, 500 mg/L, the percentage of solubilized organic carbon was identical to the other test solutions. However, at this concentration, the texture of the prepared solution was not suitable for the ecotoxicity tests. Thus, the maximum concentration tested was limited to 200 mg/L.
The TOX20022 being composed of 80 to 100% lipoamino acid, the follow-up of the solubilized organic carbon content shows that a significant part of the element is present in the test solutions but does not allow to distinguish the part of lipoamino acid dissolved from to the other constituents potentially present in the tested product (which may represent up to 20% of the product).
In addition, it seemed that a part of the test item was absorbed, among other things, on the bar magnet used to perform the magnetic stirring.
In the remainder of the report, the test concentrations will therefore be presented in nominal concentrations of TOX20022.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna Straus 1820 (Crustacea Cladocera) coming from a continuous and balanced breeding carried out in the test facility, aged less than 24 hours at the start of the test.

Sensitivity of test organism: A test was carried out with a reference item (potassium dichromate). An EC50 value of 1.09 mg/L (1.02 - 1.16) was determined. This value, between 0.6 and 2.1 mg/L, confirms the appropriate sensitivity of the strain Daphnia magna

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

19-20°C

pH:

7.7 - 7.8

Dissolved oxygen:

8.8 - 8.9 mg/L

Conductivity:

675 - 676 (µS/cm)

Nominal and measured concentrations:

Concentration range nominal (in mg/L): 19.0 - 26.6 - 37.2 - 52.1 - 72.9 - 102.0 - 142.9 - 200.0

Details on test conditions:

Following the phase of optimization of the solubilization conditions, the test solutions were prepared at the nominal concentration of 200 mg/L in the media specific to test:
Reconstituted water (NF EN ISO 6341 test medium) for the daphnia mobility inhibition test (see Table 2)
The TOX20022 test item (200 mg) was weighed into a beaker and then transferred to a volumetric flask by rinsing the beaker with the test medium (approximately 900 mL) and made up to 1000 mL.
Very rapid magnetic stirring was then carried out for 1 hour. The samples for the preparation of the test solutions were taken under stirring.
The pH was adjusted to a value of 8.3.
This test was carried out in accordance with the protocol described in the OECD guideline 202: “Daphnia sp., Immediate immobilization test (April 2004)”.
Young daphnids, aged less than 24 hours at the start of the test, were exposed to the test item at a range concentration over a 48-hour period. The test was carried out in semi-static condition with renewal of the test solutions after 24 hours of exposure. The immobilization of the organisms was measured at 24 and 48 hours.


Test conditions

- Test organism: Daphnia magna Straus 1820 (Crustacea Cladocera) coming from a continuous and balanced breeding carried out in the test facility, aged less than 24 hours at the start of the test.
- Sensitivity of test organism: A test was carried out with a reference item (potassium dichromate). An EC50 value of 1.09 mg/L (1.02 - 1.16) was determined. This value, between 0.6 and 2.1 mg/L, confirms the appropriate sensitivity of the strain Daphnia magna
- Vessels: Single-use glass tubes filled with 10 mL of test solution
- Number of organisms: 20 daphnia divided into 4 groups of 5 animals for each test solution
- Loading: 2 mL of test solution for each daphnid
- Concentration range nominal (in mg/L): 19.0 - 26.6 - 37.2 - 52.1 - 72.9 - 102.0 - 142.9 - 200.0
- Renewal: Stock solution, controls and test solutions (with and without organisms) after 24 hours of testing
- Feeding: None within the test period
- Aeration: None within the test period
- Environmental conditions: Temperature between 19 and 20°C; in the dark
- Exposure time: 48 hours
- Effect measured: Immobilization (Daphnids that are not able to swim within 15 seconds after gentle agitation of the test vessel are considered to be immobilised (even if they can still move their antennae))

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 200 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No significant effect of the TOX20022 test item was observed on the mobility of daphnids at the highest concentration tested (nominal concentration 200 mg/L).

Validity criteria
- In the control vessels, the immobilization of the daphnids did not exceed 10% at the end of the
test (0%).
- The dissolved oxygen concentration at the end of the test was >= 3 mg/L in control and in test
concentrations.
The conditions are simultaneously satisfied, the results obtained can therefore be considered valid.

Table: Inhibition of the mobility of daphnia after 24 hours and 48 hours of exposure

Nominal test concentration (mg/L)	Observation at 24h					Observation at 48h
	1	2	3	4	% of immobilisation	1	2	3	4	% of immobilisation
Control	0	0	0	0	0	0	0	0	0	0
19.0	0	0	0	0	0	0	0	0	0	0
26.6	0	0	0	0	0	0	0	0	0	0
37.2	0	0	0	0	0	0	0	0	0	0
52.1	0	0	0	0	0	0	0	0	0	0
72.9	0	0	0	0	0	0	0	1	0	5
102.0	0	0	0	0	0	0	0	0	0	0
142.9	0	0	0	0	0	1	0	1	0	10
200.0	0	1	0	1	10	0	1	0	1	10

 

Validity criteria fulfilled:

yes

Conclusions:

No significant effect of the TOX20022 test item was observed on the mobility of daphnids at the highest concentration tested (nominal concentration 200 mg/L).

Description of key information

No significant effect of the registered substance was observed on the mobility of daphnids at the highest concentration tested (nominal concentration 200 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 200 mg/L