Bis(2,3-epoxypropyl) phthalate

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)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

yes

Test organisms (species):

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

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 degrees Celcius

pH:

7.6-8.6

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

9.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

cell number

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the growth of Pseudokirchneriella subcapitata has been investigated over a 72-Hour period and based on the geometric mean measured test concentrations gave the following results:
Response Variable EC50 (mg/L) 95% Confidence Limits (mg/L) No Observed Effect Concentration (NOEC) (mg/L) Lowest Observed Effect Concentration (LOEC) (mg/L)
Growth Rate 9.4 7.9-11 0.66 1.8
Yield 3.5 3.0-4.0 0.66 1.8

Executive summary:

Introduction

A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed that described in the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009.

Methods

Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing.

A preliminary media preparation trial indicated that a dissolved test item concentration of approximately 85 mg/L was obtained from a saturated solution method of preparation indicating this to be the limit of water solubility of this item under test conditions.

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to solutions of the test item at nominal concentrations of 1.0, 3.2, 10, 32 and 100% v/v saturated solution (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C. The test item solutions were prepared by stirring an excess (100 mg/L) of test item in culture medium using a propeller stirrer at approximately 1500 rpm for 24 hours. After the stirring period any undissolved test item was removed by filtration (0.2 μm Sartorius Sartopore filter, first approximate 1 liter discarded in order to pre-condition the filter) to produce a 100% v/v saturated solution of the test item. This saturated solution was then further diluted as necessary, to provide the remaining test groups.

Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter® Multisizer Particle Counter.

Results

Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.79 to 83 mg/L. Overall there was a general decline in measured concentrations following each 24-Hour period in the range of 0.65 to 73 mg/L at 24 hours, 0.74 to 62 mg/L at 48 hours and 0.47 to 57 mg/L at 72 hours.

Given this decline in measured concentrations it was considered appropriate to calculate the results based on the geometric mean measured test concentration only in order to give a “worst case” analysis of the data.

Exposure of Pseudokirchneriella subcapitata to the test item gave the following results based on the geometric mean measured test concentrations:

Response Variable	EC50 (mg/L)	95% Confidence Limits (mg/L)	No Observed Effect Concentration (NOEC) (mg/L)	Lowest Observed Effect Concentration (LOEC) (mg/L)
Growth Rate	9.4	7.9 - 11	0.66	1.8
Yield	3.5	3.0 - 4.0	0.66	1.8

Description of key information

Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.79 to 83 mg/L. Overall there was a general decline in measured concentrations following each 24-Hour period in the range of 0.65 to 73 mg/L at 24 hours, 0.74 to 62 mg/L at 48 hours and 0.47 to 57 mg/L at 72 hours.

Given this decline in measured concentrations it was considered appropriate to calculate the results based on the geometric mean measured test concentration only in order to give a “worst case” analysis of the data.

Exposure of Pseudokirchneriella subcapitata to the test item gave the following results based on the geometric mean measured test concentrations:

Response Variable	EC50 (mg/L)	95% Confidence Limits (mg/L)	No Observed Effect Concentration (NOEC) (mg/L)	Lowest Observed Effect Concentration (LOEC) (mg/L)
Growth Rate	9.4	7.9 - 11	0.66	1.8
Yield	3.5	3.0 - 4.0	0.66	1.8

Key value for chemical safety assessment

EC50 for freshwater algae:

3.5 mg/L