1-hydroxy-4-(p-toluidino)anthraquinone

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:

EU Method C.3 (Algal Inhibition test)

Deviations:

yes

Remarks:

see 'Principles of method if other than guideline'

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

yes

Remarks:

see 'Principles of method if other than guideline'

Principles of method if other than guideline:

The pH value increased by more than 1.5 pH units. This increase is not regarded to be relevant to the results as all validity criteria were met.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

HPLC-MS/MS

Details on sampling:

Sampling schedule:
Control: at 72 hours
Test concentration/s: at 0, 24, 48 and 72 hours

Vehicle:

no

Remarks:

ultra turrax, ultrasonic bath, magnetic stirrer, folded filter

Details on test solutions:

Pre-treatment of test item and preparation of test item concentrations
- 199.8 mg of the test item were added to 2 litres of dilution water, treated for 1 h in an ultrasonic bath and stirred for 24 h on a magnetic stirrer
- undissolved particles of the test item were removed by filtration using a folded filter (pore size 7 - 12 μm)
- pH was measured to be 7.8
- to produce the different test item concentrations appropriate amounts of the stock solution were diluted with dilution water to a volume of 100 mL

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Name: Desmodesmus subspicatus (formerly Scene-desmus subspicatus) Strain No. 86.81 SAG
- Source: Strain of the test species obtained from 'The Collection of Algal Cultures' of the Institute of Plant Physiology at the University of Göttingen (Germany).
- Maintenance and Acclimatisation: Exponentially growing stock cultures were maintained in the test facility under constant temperature conditions (21 - 24 °C with a maximum fluctuation of +/- 2 °C) at a light intensity in the range 60 to 120 μE x m-2 x s-1 (measured in the range 400 to 700 nm using a spherical quantum flux meter). The growth medium (according to BRINGMANN & KÜHN (1977)) was renewed once a week. Cell density measurements were made using a microcell counter, Sysmex F300, Digitana.
- Preparation of pre cultures: Pre cultures were set up three days before the start of a test. They were grown under identical exposure conditions as the stock cultures, except from the use of a different growth medium.
- Test cultures: The algal inocula for the test were taken from an exponentially growing pre culture and were mixed with the growth medium to make up to a final cell density of about 5000 cells per millilitre in the test medium.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

1.3 °dH (= 22.5 mg/L CaCO3)

Test temperature:

21 - 24 °C

pH:

7.9 - 10.0

Nominal and measured concentrations:

nominal [mg/L]: 25, 50, 100
measured (geometric mean) [mg/L]: 0.298, 0.532, 1.122
Effective concentrations ranged from 1.2 % to 1.6 % of nominal values at 0 hours, from 0.82 % to 1.0 % of nominal values at 24 hours, from 0.62% to 1.1 % of nominal values at 48 hours and from 0.34 % to 1.3 % of nominal values at 72 hours.

Details on test conditions:

Exposure conditions
- Test vessels: 300 mL Erlenmeyer flasks with cotton stoppers, test volume: 100 mL
- Culturing apparatus: Shaking incubator in which a temperature in the range 21 °C to 24 °C was maintained at +/- 2 °C, and continuous uniform illumination was provided in the spectral range 400 to 700 nm. Temperature was measured and recorded daily.
- Light intensity: A light intensity ranging from 60 to 120 μE x m-2 x s-1, or an equivalent range of 4000 to 8000 lux, was measured. The light intensity was checked before the start of the study.
- Cell density measurements: Cell densities were measured in a microcell counter (Sysmex F300, Digitana) by taking small aliquots from each test flask, which were not replaced.
- Experimental design: 3 concentrations plus 1 control, 3 replicates per concentration, 3 replicates per control
- Initial cell density in test cultures: approx. 5000 cells per millilitre
- additionally highest test concentration without algae
- test item concentrations: 25, 50 and 100 mg/L
- Method of administration: stock solution
- Duration of exposure: 72 hours
- Criteria of effects: item-induced inhibition of yield [y] and growth rate [r] of the algal population

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 1.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 1.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

No toxic effects against algae were observed at the limit of water solubility under exposure conditions.

Validity criteria fulfilled:

yes

Remarks:

cell density in the control cultures increased by a factor of at least 16 within 72 h, CV for section-by-section specific growth rates in control <= 35 %, CV of average specific growth rates during whole test period in replicate control cultures <= 7 %

Conclusions:

After 72 h no toxic effect of Solvent Violet 13 against algae were observed at the limit of water solubility under exposure conditions.

Executive summary:

This study was performed to assess the adverse effects of Solvent Violet 13 on the growth rate (and yield) of a population of the planktonic freshwater algal species Desmodesmus subspicatus (former name: Scenedesmus subspicatus) over several generations.

The study was conducted in accordance with Commission Regulation (EC) No 761/2009 amending Regulation No 440/2008, Method C.3 ‘Freshwater Alga and Cyanobacteria, Growth inhibition test’ (2009) which is equivalent to OECD Guideline for Testing of Chemicals No. 201 (2006).

Exponentially growing algal cells were exposed for a period of 72 hours to a range of concentrations, nominally 25, 50 and 100 mg/L of Solvent Violet 13 dissolved in dilution water. Auxiliaries used to prepare the test media were an ultra turrax, an ultrasonic bath, a magnetic stirrer and a folded filter. During the test a temperature range of 21 - 24 °C was maintained in the test vessels. The pH was measured at the beginning of the test and after 72 hours of exposure.

The cell densities were measured at 24 hour intervals. Inhibition of the algal population was measured as reduction in growth rate (index r), relative to control cultures grown under identical conditions. Growth rates were also used to calculate a No Observed Effect Concentration (NOEC) and a Lowest Observed Effect Concentration (LOEC) according to Williams Multiple Sequential t-test Procedure. The following values were determined (geometric mean): ErC50 > 1.1, NOEC ≥ 1.1

No toxic effects against algae were observed at the limit of water solubility under exposure conditions.

The results are expressed in terms of geometric mean measured values. Effective concentrations ranged from 1.2 % to 1.6 % of nominal values at 0 hours, from 0.82 % to 1.0 % of nominal values at 24 hours, from 0.62 % to 1.1 % of nominal values at 48 hours and from 0.34 % to 1.3 % of nominal values at 72 hours.

Description of key information

This study was performed to assess the adverse effects of Solvent Violet 13 on the growth rate (and yield) of a population of the planktonic freshwater algal species Desmodesmus subspicatus (former name: Scenedesmus subspicatus) over several generationsin accordance with EC C.3 ‘Freshwater Alga and Cyanobacteria, Growth inhibition test’ (2009) which is equivalent to OECD Guideline for Testing of Chemicals No. 201 (2006).

Exponentially growing algal cells were exposed for a period of 72 hours to a range of concentrations, nominally 25, 50 and 100 mg/L of Solvent Violet 13 dissolved in dilution water. The following values were determined (geometric mean): ErC50 > 1.1, NOEC ≥ 1.1. Effective concentrations ranged from 1.2 % to 1.6 % of nominal values at 0 hours, from 0.82 % to 1.0 % of nominal values at 24 hours, from 0.62 % to 1.1 % of nominal values at 48 hours and from 0.34 % to 1.3 % of nominal values at 72 hours.

No toxic effects against algae were observed at the limit of water solubility under exposure conditions.

Key value for chemical safety assessment

EC50 for freshwater algae:

1.1 mg/L

EC10 or NOEC for freshwater algae:

1.1 mg/L

Additional information

Should read: EC50 > 1.1 mg/L, NOEC >= 1.1 mg/L