Tri-2-propyn-1-yl phosphate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

OECD Guidelines for the Testing of Chemicals No. 201, adopted 23. Mar. 2006, An-nex 5 corrected: 28 July 2011

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Commission Regulation (EU) No. 2016/266 amending Regulation (EC) No. 440/2008, Annex IV

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

tris(prop-2-yn-1-yl) phosphate

EC Number:

853-966-8

Cas Number:

1779-34-6

Molecular formula:

C9H9O4P

IUPAC Name:

tris(prop-2-yn-1-yl) phosphate

Specific details on test material used for the study:

Test Item: Phosphoric acid,tri-2-propargyl ester
Lot No.: H219121101
CAS No.: 1779-34-6
EINECS-No.: 853-966-8
Molecular Formula: C9H9O4P
Molecular Weight: 212 g/mol
Purity: 99%
Appearance: Yellow liquid
Homogeneity: Homogenous

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

- Sampling preparation: Before the measurement at the start and the end of the test, 250 µL of the taken sample from the concentrations 32 mg/L were diluted with 750 µL algal medium (4-fold) and 100 µL of the taken sample from the concentrations 100 mg/L were diluted with 900 µL algal medium and 100 µL (10-fold).
- Sample storage conditions before analysis: The test item was stored in the test facility in a closed vessel at room temperature (20 ± 5 °C).

Test solutions

Vehicle:

no

Details on test solutions:

- Preparation: A stock solution containing 100.0 mg/L (corresponds to 83.6 µL/L based on a density of 1.196 g/cm3 at 20 °C given by the sponsor) test item in algal medium (demineralised water enriched with minerals but without algae) was prepared.
The lower treatments (1 / 3.2 / 10 / 32 mg/L nominal) were prepared by dilution of this stock solution with algal medium.

- Positive Control: Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a separate reference test.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
-Specification
Unicellular freshwater green alga.
Genus: Desmodesmus
Species: subspicatus
SAG Strain Number: 86.81
Taxonomic position: Chlorophyta - Chlorophyceae

-Origin and Culture
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. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.3 – 22.8 °C

pH:

7.7 - 7.8 (test start)
7.9 - 8.2 (test end)

Nominal and measured concentrations:

nominal concentration: 1, 3.2, 10, 32 and 100 mg/L
measured concentration: 0.98, 3.27, 9.59, 32.83 and 101.15 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass flasks total volume 65 mL
- Initial cells density: 2420 cells.mL-1
- Control end cells density: 2420 cells.mL-1
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes
- Light intensity: 4440 - 8880 lux (specified range)
- Photoperiod: continuous light

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: agar medium
- Culture medium different from test medium: No
- Intervals of water quality measurement: The pH values measured at the start and the end of the test are stated.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Electronic particle counter

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 5

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Effect concentrations 7

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 8

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield

Details on results:

The study was performed using 5 concentrations ranging from 1 to 100 mg/L (nominal). Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concen-tration of each replicate was determined by measuring the cell numbers every 24 ± 1 hours with an electronic particle counter. Growth rate µ and the yield were determined from the cell number at the respective observation times.
No significant inhibition of algal growth was observed at the highest tested concentration. Therefore, the biological endpoints were stated as being higher than 100 mg/L.

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC.
The measured concentrations lay between 96 % and 103 % of the nominal concentra-tions at the beginning of the test and between 105 % and 117 % of the nominal concen-trations at the end of the test. Therefore, the determination of the results was based on the nominal concentrations (see OECD guidance document No. 23 (§ 176)).

The 72h-EC50 values of potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were de-termined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.64 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study, the 72 hour EC50 (growth rate) of the test material was determined to greater than 100 mg/l.

Executive summary:

In this guideline (OECD 201) study conducted with GLP certification, the objective of this study was to evaluate the toxicity of Tri-2-propyn-1-yl phosphate (LDY196) towards Desmodesmus sub-spicatus. This freshwater green alga was chosen as a typical species of phytoplankton. A non GLP pre-test was conducted to find the concentrations that cause algae growth inhibition. Based on the results of the pre-test, a definitive test was carried out with the following concentrations of test substance: 0 (control); 1, 3.2, 10, 32 and 100 mg/L. The test was incubated during 72 hours inside chambers with controlled conditions of luminosity, temperature, and agitation. The 72-hours EyC50 value was >100 mg/L and the 72-hours ErC50 value was >100 mg/L. The highest test substance concentration which no observed significant adverse effect (NOEC) on algal growth was >=100 mg/L and the lowest test substance concentration at which was observed significant reducing effect on growth (LOEC) was >=100 mg/L.