E17-194T, (P,P-diethyl, monoester with 1,2 propanediol)_

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

yes

Remarks:

Deviations considerd uncritical

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

17-194T, Lot #: 300567-78-7
Composition: P,P-diethyl, monoester with 1,2 propanediol - 92.9%, CAS #2230512-72-6
Physical Description: Clear, transparent liquid
pH: Neutral to slightly acidic
Stability: Test substance was expected to be stable for the duration of testing.
Expiration Date: aug 30, 2022

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L
- Sampling method: The concentration of the test item in the test solutions was measured at the start and at the end of the test. To avoid adsorption onto the algae cells, samples for the analytical determination were tak-en from the replicates without algae.
- Sample storage conditions before analysis:

Vehicle:

no

Details on test solutions:

All solutions were sterilized before use.
Composition of the Solutions:
Stock Solution I
NH4Cl 1500 mg
MgCl2*6H2O 1200 mg
CaCl2*2H2O 1800 mg
MgSO4*7H2O 1500 mg
KH2PO4 160 mg
H2O deionised ad 1000 mL

Stock Solution II
FeCl3*6H2O 64 mg
Na2EDTA*2H2O 100 mg
H2O deionised ad 1000 mL

Stock Solution III
H3BO3 185 mg
MnCl2*4H2O 415 mg
ZnCl2 3 mg
CoCl2*6H2O 1.5 mg
CuCl2*2H2O 0.01 mg
Na2MoO4*2H2O 7 mg
H2O deionised ad 1000 mL
Stock Solution IV
NaHCO3 50 g
H2O deionised ad 1000 mL

Algal medium
Stock solution I 10.0 mL
Stock solution II 1.0 mL
Stock solution III 1.0 mL
Stock solution IV 1.0 mL
H2O deionised ad 1000 mL

Stock solutions I and III and the deionised water were sterilized using an autoclave. Stock solutions II and IV were sterilized using filtration. The algal medium corresponds to the OECD TG 201 medium.

Deviations from the nominal weighted loads were less than 5 %.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Unicellular freshwater green alga.
Genus Desmodesmus
Species subspicatus
SAG Strain Number 86.81
Taxonomic position Chlorophyta - Chlorophyceae
- Source (laboratory, culture collection):The culture of Desmodesmus subspicatus was obtained in May 2020 by MBM Science-bridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae are kept as stock culture on solid agar at 2 - 8 °C.
- Age of inoculum (at test initiation):
- Method of cultivation:From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Remarks on exposure duration:

The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter.

Test temperature:

21.7 - 22.8 °C

pH:

7.4

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks total volume 65 mL
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 45 ml
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): no
- Renewal rate of test solution (frequency/flow rate): no
- Initial cells density: 2160 Cell Number/mL
- Control end cells density: at 72 h 346277 Cell Number/mL
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): non

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: demineralised water
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: 4 days under test conditions
- Light intensity and quality: within the specified range (4440 – 8880 Lux)
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline:
- Range finding study : yes
- Test concentrations: 1 / 10 / 100 mg/l
- Results used to determine the conditions for the definitive study: no toxicity was observed

CULTURING APPARATUS
-Details on culturing apparatus used:

Reference substance (positive control):

yes

Remarks:

potassium dichromate (K2Cr2O7, CAS No. 7778-50-9)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

yield

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

yield

Validity criteria fulfilled:

yes

Conclusions:

The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L (nominal). Inhibition of algal growth was not observed in the test solutions.

Executive summary:

The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L (nominal). Inhibition of algal growth was not observed in the test solutions.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L