Reaction mass of 3,7-bis(diethylamino)phenoxazin-5-ium chloride and 3,7-bis(diethylamino)phenoxazin-5-ium trichlorozincate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

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)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

The samples were stored deep-frozen (-20°C) until the analysis was performed

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- Specie: Scenedesmus subspicatus Chodat
- Strain: 8681 SAG
- The algae were grown in the laboratories under standardized conditions according to the OECD Guideline 201.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

20.5 - 23 °C

pH:

8.03 - 8.5

Nominal and measured concentrations:

6.25, 12.5, 25, 50 and 100 µg/l (nominal) the analysed test media amounted to 85.1 - 106.5 % of the nominal values

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

43.2 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

22.7 µg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

biomass

In the lowest concentration tested of nominal 6.25 µg/l, a greater growth inhibition was observed than in the next higher concentration (12.5 µg/l). The reason of this effect is unknown, but obviously not a toxic effect of the test substance, since first in the concentration range of 12.5 to 100 µg/l a clear concentration-effect-relation was determined.

Validity criteria fulfilled:

yes

Conclusions:

Biomass: EyC50 (96h) = 22.7 µg/l
Growth rate: ErC50 (96h) = 43.2 µg/l

Executive summary:

The influence of the substance on the growth of the greenalga Scenedesmus subspicatus Chodat was investigated in a 96 -hour static test according to the OECD 201, in according to the GLP principles. The test was performed at nominal concentrations of 6.25, 12.5, 25, 50 and 100 µg/l. During test duration, the test article concentrations in the analysed test media were higher than 80 % of the nominal values.

Results:

Biomass: EyC50 (96h) = 22.7 µg/l

Growth rate: ErC50 (96h) = 43.2 µg/l

Description of key information

ErC50 (96h) = 43.2 µg/l

Key value for chemical safety assessment

EC50 for freshwater algae:

43.2 µg/L