sodium;2-chloroprop-2-enoate;hydrate

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:

April - May 2018

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)

Version / remarks:

2006

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

Due to complexity of test item, test concentration analysis was not possible.

Vehicle:

no

Details on test solutions:

Stock solution was prepared in the OECD alga medium. Stock solution was prepared by weighing required quantity of test item in a beaker, to this small volume of OECD alga media was added and stirred well using a glass rod, after complete solubility, test formulation was transferred to measuring cylinder, the beaker was rinsed with OECD alga media and transferred again to measuring cylinder, rinsing process was repeated until the complete transfer of test contents. The required test concentrations were prepared by adding appropriate amount of stock solutions and make up to required volume using OECD alga medium. A homogeneous distribution of the test item within the stock solution was achieved by means of vortexing shortly before preparation of the test vessels.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Strain: ATCC 22662
- Source: American Type Culture Collection
- Method of cultivation: in OECD alga medium

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

22.1 to 22.6 °C

pH:

8.00 to 8.10

Nominal and measured concentrations:

Nominal concentration: 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks
- Material, fill volume: glass, 250 mL
- Initial cells density: 5478 cells/mL
- Control end cells density: 801167 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, OECD algae medium

TEST MEDIUM PARAMETERS
- Preparation of dilution water: OECD algae medium as described in OECD guideline 201

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Light intensity and quality: 5247 to 5842 Lux

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: with counting chamber after 24, 48 and 72 h

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

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

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

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:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

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:

- Exponential growth in the control: yes
- Observation of abnormalities: no
- Unusual cell shape: no
- Colour differences: no
- Flocculation: no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Any stimulation of growth found in any treatment: no
- Any observations that might cause a difference between measured and nominal values: no

Results with reference substance (positive control):

Reference standard study (BIO-ET 233), with 3,5-Dichlorophenol obtained growth rate inhibition ErC50 of 1.60 mg/L and inhibition in yield EyC50 was found to be 1.28 mg/L. This 72 hours growth rate inhibition and percent inhibition in yield lies within the validity criteria acceptance range and establishes the acceptability of test system response and test procedures followed.

Validity criteria fulfilled:

yes

Conclusions:

From the experiment conducted under standard experimental conditions, the 72 hours ErC50 and ErC10 (growth rate) and EyC50 and EyC10 (yield) of 2- Chloroacrylic sodium salt on Raphidocelis subcapitata is >100 mg/L. The 72 hours NOEC is 100 mg/L. The results are based on the nominal concentrations.

Executive summary:

The test item was assessed on Raphidocelis subcapitata for Growth Inhibition Test as per the OECD Guidelines for Testing of Chemicals (Section 2), Effects on Biotic Systems, Guideline No. 201, “Freshwater Alga and Cyanobacteria, Growth Inhibition Test” adopted on 23 March 2006. A range finding study was conducted with six concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L along with control, each concentration contains 2 replicates except control possessing 3 replicates. The algal growth (cell density) was assessed at 24, 48 and 72 hours of post-exposure during the test. During the range finding study, exponentially growing cells (5594 cells/mL) were exposed to range of selected concentrations. The growth rate inhibition of 0.06, 0.44, 0.97, 1.28, 2.08 and 2.08% were observed in the tested concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of the test item respectively as compared with the control. Percent inhibition in yield of 0.3, 2.3, 4.9, 6.4, 8.1 and 10.2% was observed in the tested concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L respectivelyas compared with the control. Based on the results of range finding study, a limit test was conducted at the concentration of 100 mg/L along with control having 6 replicates. The algal growth (cell density) was assessed at 24, 48 and 72 hours post-exposure. Exponentially growing alga cells (5478 cells/mL) were exposed to the limit concentration. A growth rate inhibition of 0.55% was observed in the tested concentration of 100 mg/L respectively as compared with the control. Similarly, inhibition in yield of 2.8% was observed in the tested concentration of 100 mg/L. The present alga growth inhibition study fulfills the validity criteria of the test. Due to complexity of test item, test concentration analysis was not performed, all results are based on nominal values. From the experiment conducted under standard experimental conditions, the 72 hours ErC50 and ErC10 (growth rate) and EyC50 and EyC10(yield) is >100 mg/L. The 72 hours No Observed Effect Concentration (NOEC) is 100 mg/L and the Lowest observed effect concentration (LOEC) is >100 mg/L. The results are based on the nominal concentrations.

Description of key information

From the experiment conducted under standard experimental conditions, the 72 hours ErC50 and ErC10 (growth rate) and EyC50 and EyC10 (yield) of 2- Chloroacrylic sodium salt on Raphidocelis subcapitata is >100 mg/L. The 72 hours NOEC is 100 mg/L. The results are based on the nominal concentrations.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

The test item was assessed on Raphidocelis subcapitata for Growth Inhibition Test as per the OECD Guidelines for Testing of Chemicals (Section 2), Effects on Biotic Systems, Guideline No. 201, “Freshwater Alga and Cyanobacteria, Growth Inhibition Test” adopted on 23 March 2006. A range finding study was conducted with six concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L along with control, each concentration contains 2 replicates except control possessing 3 replicates. The algal growth (cell density) was assessed at 24, 48 and 72 hours of post-exposure during the test. During the range finding study, exponentially growing cells (5594 cells/mL) were exposed to range of selected concentrations. The growth rate inhibition of 0.06, 0.44, 0.97, 1.28, 2.08 and 2.08% were observed in the tested concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L of the test item respectively as compared with the control. Percent inhibition in yield of 0.3, 2.3, 4.9, 6.4, 8.1 and 10.2% was observed in the tested concentrations of 0.01, 0.1, 1.0, 10.0, 50.0 and 100.0 mg/L respectivelyas compared with the control. Based on the results of range finding study, a limit test was conducted at the concentration of 100 mg/L along with control having 6 replicates. The algal growth (cell density) was assessed at 24, 48 and 72 hours post-exposure. Exponentially growing alga cells (5478 cells/mL) were exposed to the limit concentration. A growth rate inhibition of 0.55% was observed in the tested concentration of 100 mg/L respectively as compared with the control. Similarly, inhibition in yield of 2.8% was observed in the tested concentration of 100 mg/L. The present alga growth inhibition study fulfills the validity criteria of the test. Due to complexity of test item, test concentration analysis was not performed, all results are based on nominal values. From the experiment conducted under standard experimental conditions, the 72 hours ErC50 and ErC10 (growth rate) and EyC50 and EyC10(yield) is >100 mg/L. The 72 hours No Observed Effect Concentration (NOEC) is 100 mg/L and the Lowest observed effect concentration (LOEC) is >100 mg/L. The results are based on the nominal concentrations.