Enzymatic hydrolyis products of Candida Saitoana

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

Study period:

February - March 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Enzymatic hydrolyis products of Candida Saitoana

EC Number:

952-608-9

IUPAC Name:

Enzymatic hydrolyis products of Candida Saitoana

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

In order to verify the initial concentrations and maintenance of the exposure concentrations of the test item during the ecotoxicological testing, chemical analyses in daphnids test solutions were performed according to the Analytical Protocol FCBA Chimie No.430-e version 2: Method for the chemical analysis of Total Carbon (TC) in samples containing the test item from daphnids ecotoxicology solutions by a Total Organic Carbon Analyzer (described in the study 18/1136F/c and the following protocol:
- In Fresh solutions (at the beginning of the test:T0h and for the renewal at T24h), these solutions were analysed taken directly from the starting solutions without daphnids
- in Old solutions (before renewal T24h and at the end of the test T48h), two test tubes were pooled and analyzed
- for the Control (i.e. daphnids test medium filtered), and the concentration 100 mg/L

Schedule analysis at initial time:
Control Fresh T0h
100 mg/L Fresh T0h
These solutions were analysed taken directly from the starting solutions without daphnids.

Schedule analysis at T24h:
Control Old T24h
100 mg/L Old T24h
Control Fresh T24h
100 mg/L Fresh T24h

Schedule analysis at final time T48h:
Control Old T48h
100 mg/L Old T48h

The measured concentrations of the test item did not vary more than ± 20 % of nominal or initial measured concentration during the test.

Test solutions

Vehicle:

no

Details on test solutions:

The test item was soluble in the test medium.
At the request of the sponsor, the test medium and the solution (100 mg test item/L) were filtered through a membrane filter (cellulose acetate) with a mesh size of 0.22 μm to sterilizing and all the manipulations were done under sterile conditions to prevent contamination.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna Straus, clone number 5, from at least the third generation (i.e. the third brood) obtained with a non-cyclic parthenogenesis reproduction.
The daphnids breeding was carried out in closed bottles placed in a climatic chamber free from any toxic vapour and in medium M4.
Daphnids used in this experimentation were previously filtered in order to obtain animals from a size between 560 µm and 800 µm (corresponding to daphnids less than 24 hours old).

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

none

Test conditions

Hardness:

250 mg/L of CaCO3

Test temperature:

19.7 – 20.0°C

pH:

7.9

Dissolved oxygen:

9.0 mg/L

Salinity:

no data

Conductivity:

no data

Nominal and measured concentrations:

Nominal concentration : Test item 100 mg/L
Measured concentration: 101.7 mg/L (at initial time) and 103.9 mg/L (after 24 hours of exposure)
Measured concentration: 101.4 mg/L (at initial time) and 101.9 mg/L (after 48 hours of exposure)

Details on test conditions:

The test was performed in the dark between 18 and 22°C but constant within ±1°C. Daphnids were not fed during the test period.
Observations of the daphnid’s immobility and behaviour were done after 24 and 48 hours in control and exposed groups.
Any sign of stress observed on the daphnids after 48 hours of exposure to the test item were reported.
pH and dissolved oxygen were measured before and after renewal of solutions (including the controls).

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: highest tested concentration

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: highest tested concentration

Details on results:

- No immobilization was observed at 24 h and 48 h (including controls).
- No sign of stress was observed on the mobile daphnids after 48 h of exposure

Results with reference substance (positive control):

The last toxic response obtained on the reference item K2Cr2O7 (February 14, 2019) indicates an EC50-24h of 1.38 mg/L (1.25 – 1.54), indicating that the daphnids sensitivity is correct (within the accepted interval of 0.6–2.1 mg/L fixed by the International Standard ISO 6341 December 2012 as mentioned in the OECD 202 Guideline) and in accordance with historical data obtained by the laboratory.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

All the validity criteria were successful.
EC50- 24h is higher than 100 mg/L (tested concentration)
EC50- 48h is higher than 100 mg/L (tested concentration)
These values are based on nominal test item concentration.
No ecotoxicity was observed after 24 hours and 48 hours of exposure during the testing at 100 mg/L of the test item.

Executive summary:

The aim of this study was to assess the effects of the test item on the daphnids Daphnia magna, according to the OECD 202 guideline, at 100 mg/L, limit test, in semi-static conditions.

 This study was carried out in accordance with the study plan no.18/1136F/d dated February 7, 2019.

There was no deviation and no amendment during this study.

 The concentrations which immobilise 50% of the daphnids exposed to the test item after 24 and 48 hours, reported as EC₅₀-24h and EC₅₀-48h were evaluated, relative to the tested concentration : 100 mg/L.

According to the sponsor, a chemical analysis of the test item in the test solutions was performed.

At the nominal concentration of 100 mg/L, the test item is considered as stable in the testing conditions because the measured concentrations of the Total Carbon did not vary more than ± 20 % of initial measured concentration during the test.

All the validity criteria were successful.

The results obtained for the test item on the toxicological endpoint “immobilisation” give an EC₅₀-24h and anEC₅₀-48h higher than the highest tested concentration,i.e. 100 mg/L, based on nominal test item concentration.