Phosphoric acid, 2-ethylhexyl ester, compd. with 2,2'-iminobis[ethanol]

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:

23/01/2006 - 30/03/2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

- Concentrations: Nominal test substance concentrations used were 0, 10.0, 17.8, 31.6, 56.2 and 100 mg/ L
- Sampling method: Growth rate observations over time.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Test material dissolved in seawater
- Controls: 1 growth rate control (for 0 hours 1 replicate, for 24, 48 and 72 hours 6 replicates per concentration). 1 positive control (3,5-dichlorophenol, 1.5 mg/ L for 24, 48 and 72 hours with 3 replicates.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): No, test material was soluble in water.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Skeletonema costatum
- Strain: CCAP1077/5
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa, Dunstaffnage.
- Method of cultivation: Guillard's f/2 medium + Si

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

Measurement time points were 0, 24, 48, 72 hours.

Test temperature:

19 - 21 °C

pH:

At 0 hours, pH was 8.09 - 8.19
At 72 hours, pH was 8.49 - 8.51

Nominal and measured concentrations:

Nominal test substance concentrations - 0, 10.0, 17.8, 31.6, 56.2 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: culture flasks
- Initial cells density: 2520 cells per mL
- Control end cells density: 16478 - 229872 cells per mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): Growth rate control (6), positive control (3)

GROWTH MEDIUM
- Detailed composition if non-standard medium was used: Guillard's f2 medium + Si

TEST MEDIUM / WATER PARAMETERS
- Alkalinity: pH 8.09 - 8.19
- Intervals of water quality measurement: 24 hour intervals

OTHER TEST CONDITIONS
- Photoperiod: continuous for 72 hours
- Light intensity and quality: 6000 - 10000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Cell number changes over time
- Determination of cell concentrations: microscopic counting

TEST CONCENTRATIONS
- Test concentrations: 0, 10, 17.8, 31.6, 56.2 and 100.0 mg/L
- Results used to determine the conditions for the definitive study: information from a previous study

Reference substance (positive control):

yes

Remarks:

3, 5 - dichlorophenol

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

11.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

16.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

16.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No
- Unusual cell shape: No
- Colour differences: No
- Any stimulation of growth found in any treatment: No
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes

Validity criteria fulfilled:

yes

Conclusions:

The test substance has an EC50 value of 5.77 mg/ L for 24 hours, 11.6 mg/L for 48 hours and 16.8 mg/ L for 72 hours. The NOEC value for 72 hours is 10.0 mg/ L and the LOEC value is 17.8 mg/ L.

Executive summary:

The study assesses the acute toxicity of 25% M528 -7 (W/W) neutralised with DEA in deionised water to marine algae. M528 -7 (W/W) was identified as the registered substance.

The study is in compliance with GLP and the testing guidelines complied with EN ISO 10253:1998. All validity criteria were met. The organism used was Skeletonema costatum in saltwater (seawater). A rangefinding test was not used as the information was obtained from a previous screening test performed by the laboratory. The definitive test used a range of nominal concentrations of 0, 10, 17.8, 31.6, 56.2 and 100 mg/ L of test substance. Test material was dissolved at 25% with DEA in deionised water to make a 1 g/ L stock from which aliquots were used for dilutions. The results of the definitive test showed that the test substance has an EC50 of 5.77 mg/ L for 24 hours, 11.6 mg/L for 48 hours and 16.8 mg/ L for 72 hours. The NOEC value for 72 hours is 10.0 mg/ L and the LOEC value is 17.8 mg/ L. The definitive test had 3 replicates per concentration, per time point. 1 growth rate control was included (0 mg/ L test substance) for all time points, with 1 replicate for 0 hours and 6 replicates for 24, 48 and 72 hours. One positive control (reference substance: 3, 5 -dichlorophenol) was included with 3 replicates per time point.

Description of key information

The study assesses the acute toxicity of 25% M528 -7 (W/W) neutralised with DEA in deionised water to marine algae. M528 -7 (W/W) was identified as the registered substance.

The study is in compliance with GLP and the testing guidelines complied with EN ISO 10253:1998. All validity criteria were met. The organism used was Skeletonema costatum in saltwater (seawater). A rangefinding test was not used as the information was obtained from a previous screening test performed by the laboratory. The definitive test used a range of nominal concentrations of 0, 10, 17.8, 31.6, 56.2 and 100 mg/ L of test substance. Test material was dissolved at 25% with DEA in deionised water to make a 1 g/ L stock from which aliquots were used for dilutions. The results of the definitive test showed that the test substance has an EC50 of 5.77 mg/ L for 24 hours, 11.6 mg/L for 48 hours and 16.8 mg/ L for 72 hours. The NOEC value for 72 hours is 10.0 mg/ L and the LOEC value is 17.8 mg/ L. The definitive test had 3 replicates per concentration, per time point. 1 growth rate control was included (0 mg/ L test substance) for all time points, with 1 replicate for 0 hours and 6 replicates for 24, 48 and 72 hours. One positive control (reference substance: 3, 5 -dichlorophenol) was included with 3 replicates per time point.

Key value for chemical safety assessment

EC50 for marine water algae:

16.8 mg/L