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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
October from 24th to 27th, 1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Justification for Read Across is explained in the endpoint summary and it is further detailed in the report attached to the IUCLID section 13.
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PRE-TREATMENT
A direct weighing was prepared to produce the only test concentration (100 mg/l). Therefore the test substance was weighted into dilution water (purified millipore water) and then treated for one hour in an ultrasonic- bath. Afterwards the solution was stirred for 24 hours on a magnetic stirrer. Insoluble particles were filtered with a glass fiber filter (pore size 4-7 µm). For test item concentration and the control 1 replicate were prepared. All flasks were sealed with cotton stoppers.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: Plant Physiology Institute of Göttingen Universitet.
- Method of cultivation: weekly transfer of root crops.

ACCLIMATION
- Culturing media and conditions: same as test.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Test temperature:
23 ± 2 °C
pH:
10.5 (at 72 hours)
Nominal and measured concentrations:
100 mg/l nominal
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer flasks (300 ml) with ground-glass stoppers.
- Material, size, headspace, fill volume: 10 ml.
- Initial cells density: mathematically calculated, cell density of 10000 cells / ml.
- No. of vessels per concentration: one replicate.
- No. of vessels per control: one replicate, inoculum in nutrient solution and dilution water.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water.

OTHER TEST CONDITIONS
- Light intensity and quality: photosynthetically effective Raumbe-radiation, intensity of 120 micro-Einstein / m2 · s.
- Culuring apparatus: storage in the light cabinet with shaking (PVP).

EFFECT PARAMETERS MEASURED
- Inspection: daily inspection of the population growth of unicellular green algae over a test period of 3 days.
- Counting: Microcell Counter Sysmex F300 Digitana.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
Growth rate was recorded at 1.2 l/d in both tested and control group.
No Observed Effect Level ≥ 100 mg/l (nominal)
Conclusions:
EC50 (72 h) > 100 mg/l (nominal)
Executive summary:

The acute toxic potential of the test substance was tested according to the OECD guideline 201. Desmodesmus subspicatus was exposed to one nominal concentration of the test substance at 100 mg/l. The cell density was recorded 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. No toxic effects against algae were observed at a limit test concentration of 100 mg/l: the growth rate was recorded at 1.2 l/d in both tested and control group. The No Observed Effect Level resulted equal/greater than 100 mg/l (nominal).

Conclusion

EC50 (72 h) > 100 mg/l (nominal)

Description of key information

EC50 (72 h) > 100 mg/l (nominal)

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

No studies on the toxicity to aquatic algae and cyanobacteria are available for the Basic Blue 140 (BBl140). Nevertheless, a study conducted on the structural analogue Similar Substance 01 is available.

The acute toxic potential of Similar Substance 01 was tested according to the OECD guideline 201. Desmodesmus subspicatus was exposed to one nominal concentration of the test substance at 100 mg/l. The cell density was recorded 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. No toxic effects against algae were observed at a limit test concentration of 100 mg/l: the growth rate was recorded at 1.2 l/d in both tested and control group. The No Observed Effect Level resulted equal/greater than 100 mg/l (nominal).

BBl140 and Similar Substance 01 share the same phthalocyaninic core and, in both cases, they present a zwitterionic moiety formed by sulphonic acid, which conducts an acid function, and a tertiary amine on the sulphonaminic chain, characterized by a basic function. BBl140 presents a further sulphonaminic functionalization, of which chain ends with a tertiary amine that, based on the stechiometrical ratio reported in the analytical characterization, in most of the cases can be salified with acetic acid.

It is expected that this difference has not a significant impact on the toxicity to aquatic algae and cyanobacteria. The read across approach has been further detailed in the report attached to the IUCLID section 13.