ParyFree Dimer

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:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tricyclo[8.2.2.24,7]hexadeca-4,6,10,12,13,15-hexaene, 5,11,13,15-tetramethyl-

Cas Number:

205825-52-1

Molecular formula:

C20H24

IUPAC Name:

Tricyclo[8.2.2.24,7]hexadeca-4,6,10,12,13,15-hexaene, 5,11,13,15-tetramethyl-

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Batch no.: 350321
Expiry date: February 26, 2024

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Remarks:

Due to low water solubility of the test item, a solvent (acetonitrile) was used as carrier to add the test item in test medium

Details on test solutions:

The test concentration was chosen based on the water solubility value determined in a GLP study (35 µg/L).

Starting from water solubility data we have performed solubility preliminary tests in ecotoxicological matrix (reconstituted water) and following method of solutions preparation described below: 50 µg test item/L was assessed as maximum soluble tested concentration.
It corresponded to 49.8 µg PARYFREE® DIMER/L (calculated considering active ingredient content reported in the CoA, 99.6%).

Due to low water solubility of the test item, a solvent (acetonitrile) was used as carrier to add the test item in test medium. An additional control containing the solvent at the same concentration as used in the test solution was included in the test design.

Prior to the test start, a 500.0 mg test item/L stock solution was prepared by direct weighting 0.0053 g of test item into 10 mL acetonitrile solvent. The stock solution was clear and transparent with the test item totally solubilized. It was stored in a refrigerator and used again to prepare the fresh test item solution after 24 hours.
Starting from this stock solution, the test solution at 50 µg test item/L was prepared transferring 50 µL of stock solution into 500 mL of reconstituted water (according to the OECD No. 23 that recommends a maximum solvent concentration equal to 0.1 ml/L).
Test solution was clear and transparent, it was mixed for 24 hours in order to obtain the maximum test item solubilization. After stirring, it was always clear and transparent with the test item totally solubilized.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

For the test concentration, for the negative control and positive control, group of 20 daphnids were used divided into four replicates of five daphnids each

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

19.94 – 20.03°C

pH:

negative control: 7.40 - 7.81
positive control: 7.68 – 7.81
test item solution: 7.55 – 7.83

Dissolved oxygen:

negative control: 6.71 – 6.92 mg O2/L
positive control: 6.98 – 7.48 mg O2/L
test item solutions: 6.96 – 7.94 mg O2/L

Nominal and measured concentrations:

50.0 µg test item/L, corresponding to 49.8 µg PARYFREE® DIMER/L (calculated considering active ingredient content reported in the CoA, 99.6%).

Reference substance (positive control):

yes

Remarks:

reconstituted water without test item but with acetonitrile solvent

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 50 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 27.15 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

50 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Effect concentrations 4

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

27.15 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Details on results:

Since all analytical recoveries were not in the range 80 % - 120 % of the nominal concentrations, the biological results were referred to the time-weighted arithmetic mean of PARYFREE® DIMER measured concentrations, as recommended by OECD Guidance Document on testing of difficult substances No. 23, 2019 (Table 4).

No immobilization was observed and no daphnid was trapped on the test water surface or showed other signs of disease or stress.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No immobilization was observed and no daphnid was trapped on the test water surface or showed other signs of disease or stress.
The results, calculated in terms of nominal test item concentration, were as follows:
EC50 > 50 ug/l
NOEC = 50 ug/l
The results, calculated in terms of time-weighted arithmetic mean of active ingredient measured concentrations, were as follows:
EC50 > 27.15 ug/l
EC50 = 27.15 ug/l