[No public or meaningful name is available]

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)

Principles of method if other than guideline:

This method succeeded the previous OECD Guideline No. 201 'Alga, Growth Inhibition Test' (1984) and EU Method C.3 'Algal inhibition test' (1992).

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PRETREATMENT OF TEST ITEM:
- 125 mg of the test substance was added to 1 litre of dilution water
- treated for 60 s at 8000 rpm with an ultra-turrax
- stirred for 24 h on a magnetic stirrer
- undissolved particles of the test item were removed by filtration using an aseptic filter (Serum Acrodisc® 37 mm Syringe Filter with GF/02 μm Supor® Membrane PN 4525 )
- pH was measured to be pH 6.2

Test organisms (species):

other: Scenedesmus subspicatus CHODAT (New scientific name: Desmodesmus subspicatus)

Details on test organisms:

- stock culture: non-axenic strain obtained from the Institute of Plant Physiology at the University of Göttingen (Germany);  exponentially-growing stock cultures maintained under constant  temperature conditions (23 +/- 2 °C), light intensity (60 - 120 µE. x  mE-2 x sE-1), cell density measured using a microcell counter

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

No data

Test temperature:

21 - 25 +/- 2 °C

pH:

8.0 at 0 hours, 8.8 after 72 hours

Dissolved oxygen:

No data

Salinity:

No data

Details on test conditions:

TEST SYSTEM:
- test vessels: 300 ml Erlenmeyer flasks with cotton stoppers
- culturing apparatus: light chamber, temperature 21 to 25 °C, continuous uniform illumination (spectral range 400 to 700 nm) 
- light intensity: 60 - 120 µE x mE-2 x sE-1 (4000 - 8000 lx)
- test cultures: final cell density 5000 cells/ml
- method of administration: direct weighing
- test concentration: 1 (100 mg/l) plus 1 control
- replicate: 3 (per concentration), 6 (per control)
- test parameter: growth and growth rate

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

estimated

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Results relating to yield (EyCx, NOEC [y])

Details on results:

The results are expressed in terms of nominal concentrations. Recovery rates correspond to 101.3 % of nominal values at 0 hours, and to 90.1 % of nominal values at 72 hours, respectively.

Validity criteria fulfilled:

yes

Conclusions:

In 72 h the concentration of the test item which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l.

Executive summary:

In 72 h the concentration of the test item which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l. The result relates to nominal concentration as analytical monitoring shows stability of the test substance during the experiment (Currenta, 2009).

Description of key information

In 72 h the concentration of the test substance which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l. The result relates to nominal concentration as analytical monitoring shows stability of the test substance during the experiment (Currenta, 2009).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L