REAKTIVE GELB F 97494

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

Study period:

November 13, 2001 to November 16, 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Sampling method: TOC determination at 0 and 72 h

Vehicle:

yes

Details on test solutions:

PREPARATION OF STOCK SOLUTION
- Method: A stock solution was prepared by dissolving 125.4 mg of the test substance in 1 L of dilution water using a magnetic stirrer for 24 h.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: Chodat
- Source (laboratory, culture collection): Non-axenic strain of the test species obtained from 'The Collection of Algal Cultures' of the Institute of Plant Physiology at the University of Göttingen (Germany)
- Age of inoculum (at test initiation): Pre-cultures were set up three days before the start of a test.
- Method of cultivation: The algal cultures for a test were taken from an exponentially-growing pre-culture and were mixed with the nutrient medium to make up to a final cell density of about 10E4 cells/mL in the test medium.

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21°C to 25°C

pH:

7.7-10.4

Nominal and measured concentrations:

Nominal concentration: 3.1, 6.3, 13, 25, 50 and 100 mg/L
Measured concentration:
-Measured concentrations ranged from 100-130% of nominal values at 0 hours, and from 93-106% of nominal values at 72 hours, respectively.
-The test concentrations 3.1 mg/L and 6.3 mg/L were not analytically determined as the measured concentrations to be expected were below the quantization limit of the TOC determination method (2 mg/L).
-The measured concentration for the nominal concentrations of 13, 25, 50 and 100 mg/L were 16.9, 29.7, 59.3, 106 mg/L at 0 h; and 12.7, 25.4, 55.1 and 106 mg/L at 72 h.

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 ml Erlenmeyer flasks with stoppers
- Culturing apparatus: Light chamber in which a temperature in the range 21 °C to 25°C can be maintained and continuous uniform illumination is provided in the spectral range 400 to 700 nm.
- Type (delete if not applicable): closed
- Initial cells density: 10E4 cells/mL
- Experimental design: 6 test concentrations with algae , 1 control (without test substance) with algae and 1 control (with highest test substance concentration) without algae.
- Test concentrations (nominal): 3.1, 6.3, 13, 25, 50 and 100 mg/L
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Duration of exposure: 72 h

GROWTH MEDIUM
- Standard medium used: yes (OECD TG 201 medium)

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: No

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Criteria for effects: Adverse effects were monitored at 24, 48 and 72 h by determining the substance induced inhibition of growth [b] and growth rate [r] of the algal population. The 72 hour EC 50 (based on both, growth [b] and growth rate [r]), is calculated or read from the concentration/percentage response curve.
- Determination of cell density concentrations: microcell Microcell counter or microscopic counting chamber


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Test concentrations (nominal): 3.1, 6.3, 13, 25, 50 and 100 mg/L

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:

other: ErC50

Effect conc.:

> 106 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

27.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

57.2 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

other: EbC50

Effect conc.:

> 106 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

27.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

57.2 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Reported statistics and error estimates:

Multisample comparison (according to DUNNETT 1955, 1964)

Percentage inhibition of cell growth (integral of biomass) and growth rate:

Nominal concentration of test substance (mg/L)	Average of measured concentrations of test substance at 0 and 72 h (mg/L)	Percentage inhibition of cell growth [b]	Percentage inhibition of mean growth rate [r]
Control	-	0.0	0.0
3.1	-*	1.6	0.8
6.3	-*	1.9	0.1
13	14.8	-0.9	1.1
25	27.5	2.1	0.4
50	57.2	11.1	2.8
100	106	14.7	3.3

* The test concentrations 3.1 mg/L and 6.3 mg/L were not analytically determined as the measured concentrations to be expected were below the quantization limit of the TOC determination method (2 mg/L).

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study, the 72 h EbC50 and ErC50 for Desmodesmus subspicatus were > 100 mg/L (equivalent to a measured concentration of > 106 mg/L). The NOECs for biomass and growth rate were determined to be 25 mg/L (equivalent to a measured concentration of 27.5 mg/L); the corresponding LOECs were 50 mg/L (equivalent to a measured concentration of 57.2 mg/L).

Executive summary:

A study was conducted to determine the acute toxicity of the test substance to the algae Desmodesmus subspicatus according to EU Method C.3 (which is in most parts equivalent to OECD Guideline 201), in compliance with GLP.

Triplicate inocula of the algae were exposed to nominal concentrations of 0, 3.1, 6.3, 13, 25, 50 and 100 mg/L of the test substance for 72 h under static conditions. Quantification of the applied concentrations was carried out using Total Organic Carbon (TOC) determination. The organic components of the test substance corresponded to 66.1% of the molecular weight. No analytical determination was carried out at 3.1 and 6.3 mg/L as the measured concentrations to be expected were below the quantification limit of the TOC method (2 mg/L). Biomass and growth rate were determined after 0, 24, 48 and 72 h.

 

Under the conditions of the study, the 72 h EbC50 and ErC50 for Desmodesmus subspicatus were > 100 mg/L (equivalent to a measured concentration of > 106 mg/L). The NOECs for biomass and growth rate were determined to be 25 mg/L (equivalent to a measured concentration of 27.5 mg/L); the corresponding LOECs were 50 mg/L (equivalent to a measured concentration of 57.2 mg/L).

Description of key information

Under the conditions of the study, the 72 h EbC50 and ErC50 for Desmodesmus subspicatus were > 100 mg/L (equivalent to a measured concentration of > 106 mg/L). The NOECs for biomass and growth rate were determined to be 25 mg/L (equivalent to a measured concentration of 27.5 mg/L); the corresponding LOECs were 50 mg/L (equivalent to a measured concentration of 57.2 mg/L).

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

27.5 mg/L

Additional information

A study was conducted to determine the acute toxicity of the test substance to the algae Desmodesmus subspicatus according to EU Method C.3 (which is in most parts equivalent to OECD Guideline 201), in compliance with GLP.

Triplicate inocula of the algae were exposed to nominal concentrations of 0, 3.1, 6.3, 13, 25, 50 and 100 mg/L of the test substance for 72 h under static conditions. Quantification of the applied concentrations was carried out using Total Organic Carbon (TOC) determination. The organic components of the test substance corresponded to 66.1% of the molecular weight. No analytical determination was carried out at 3.1 and 6.3 mg/L as the measured concentrations to be expected were below the quantification limit of the TOC method (2 mg/L). Biomass and growth rate were determined after 0, 24, 48 and 72 h.

 

Under the conditions of the study, the 72 h EbC50 and ErC50 for Desmodesmus subspicatus were > 100 mg/L (equivalent to a measured concentration of > 106 mg/L). The NOECs for biomass and growth rate were determined to be 25 mg/L (equivalent to a measured concentration of 27.5 mg/L); the corresponding LOECs were 50 mg/L (equivalent to a measured concentration of 57.2 mg/L).