Formaldehyde, oligomeric reaction products with diethylenetriamine and phenol

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.:

0.2 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.:

0.09 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 0.20 0.18-0.23 0.048 0.13
Yield 0.090 0.070-0.12 0.022 0.048

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

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations of 0.0625, 0.125, 0.25, 0.50 and 1.0 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C.

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 85% to 98% of nominal. A decline in measured concentrations was observed after each 24-Hour interval in the range of 57% to 95% of nominal at 24 hours, 10% to 85% of nominal at 48 hours and 11% to 62% of nominal at 72 hours indicating that the test item was unstable over the test duration.

Given this decline in measured test concentrations it was considered justifiable to base the results on the geometric mean measured test concentrations in order to give a "worst case" analysis of the data. The geometric mean measured test concentrations were determined to be 0.022, 0.048, 0.13, 0.40 and 0.86 mg/L.

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	0.20	0.18 - 0.23	0.048	0.13
Yield	0.090	0.070 - 0.12	0.022	0.048

Description of key information

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	0.20	0.18-0.23	0.048	0.13
Yield	0.090	0.070-0.12	0.022	0.048

Key value for chemical safety assessment

EC50 for freshwater algae:

0.2 mg/L