Isodecyl diphenyl phosphate

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

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Purity: >90%
Batch: 900150909STG115

Analytical monitoring:

yes

Details on sampling:

The concentration and stability of the test item were verified by chemicasl analysis at 0 and 72 hours.

Vehicle:

yes

Details on test solutions:

A nominal amount of test item was dissolved in dimethylformamide.

Test organisms (species):

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

Details on test organisms:

P. subcapitata strain CCAP 278/4 were used for the test. The cultures were obtained from the Culture Collection of Alae and Protozoa (CCAP), SAMS Research Services Ltd, Scottish Marine Institue, Oban, Argyll, Scotland.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

Test temperature was maintained at 24 +/- 1 deg C.

pH:

The pH was measured throughout the test and teh pH ranged from 7.7-8.2

Nominal and measured concentrations:

A nominal amount of the test item (100mg/L) was dissolved in dimethylformamide and the volume adjusted to 10mL to give a 100 mg/10mL solvent stock solution. 100% v/v of this solution was used during the testing. Chemical analysis of this showed measured test concentrations of 0.10 and 0.11 mg/L.

Details on test conditions:

100mL of test solution was put into 250 mL glass conical flasks. Six replicates were used for the control, solvent control and 100%v/v treatment fourp. Flasks were plugged with polyurethane foam bungs and incubated at 24+/- 1 deg C under continuous illumination provided by wartm white lighting and constantly shaken for 2 hours.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 0.1 mg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

growth rate

Details on results:

No toxic effects were seen at the highest obtainable concentration.

Results with reference substance (positive control):

A positive control used potassium dichromate as the reference item at concentrations of 0.25, 0.5, 1.0, 2.0, 4.0 mg/L. Exposure conditions and data evaluation for the positive control. The following results were obtained EC50 1 mg/L and a NOEC of 0.25 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

Analysis of the 100% v/v test preparation at 0 and 72 hours showed measured test concentrations of 0.10 and 0.11 mg/L. Exposure of P. subcapitata to the test item gave EC50 calues of greater than 0.10mg/L and a NOEC of > 0.10mg/L. No toxic effects were seen at saturation.

Executive summary:

Testing was carried out following the methods outlined in the OECD 201 guideline. Analysis of the 100% v/v test preparation at 0 and 72 hours showed measured test concentrations of 0.10 and 0.11 mg/L. Exposure of P. subcapitata to the test item gave EC50 calues of > 0.10mg/L and a NOEC of > 0.10mg/L. No toxic effects were seen at saturation.

Description of key information

Testing was carried out following the methods outlined in the OECD 201 guideline. Analysis of the 100% v/v test preparation at 0 and 72 hours showed measured test concentrations of 0.10 and 0.11 mg/L. Exposure of P. subcapitata to the test item gave EC50 values of > 0.10mg/L and a NOEC of > 0.10mg/L. No toxic effects were seen at saturation.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.1 mg/L

EC10 or NOEC for freshwater algae:

0.1 mg/L

Additional information

The available studies on the acute and chronic toxicity of IDDPP towards algae show no effects below the water solubility.Values are well above the water solubility (11.2 ug/l) of the substance, IDDPP can not be classified as toxic to the environment.