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Toxicity to aquatic algae and cyanobacteria

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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 gave the following results:
Growth Rate: EC50: 86 mg/l
Yield: EC50: 6.1 mg/l

Key value for chemical safety assessment

EC50 for freshwater algae:
86 mg/L
EC10 or NOEC for freshwater algae:
1 mg/L

Additional information

Introduction

A study was perford to assess the effect of the test item on the growth of the green algaPseudokirchneriella subcapitata. Thethod followed was designed to be compatible with 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 440/2008.

Methods.

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations of 1.0, 3.2, 10, 32 and 100 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.Exposure of Pseudokirchneriella subcapitata to the test item 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

86

 

 

1.0

3.2

Yield

6.1

4.7

-

8.0

1.0

3.2

Analysis of the test preparations at 0 and 72 hours showed measured test concentrations to range from 88% to 119% of nominal indicating that the test item was stable over the test duration and so the results are based on nominal test concentrations only.