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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:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP study according to national standard method.
Qualifier:
according to guideline
Guideline:
other: DIN 38412, part 9, "Determination of inhibitory effect on the cell multiplication"
GLP compliance:
no
Analytical monitoring:
no
Details on sampling:
algal growth was checked by determination of chlorophyll A fluorescence at 0, 24, 48, 72 and 96 h.
Vehicle:
no
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Nominal and measured concentrations:
concentration of test substance: 100, 320 and 1000 mg/L
Details on test conditions:
number of replicates/concentration: 4
Reference substance (positive control):
no
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
EC10 (effect: growth rate) > 1000 mg/L (nominal),
EC50 (effect: growth rate) > 1000 mg/L (nominal).
Executive summary:

Test performed according to DIN 38412, part 9, "Determination of inhibitory effect on the cell multiplication". EC10 (effect: growth rate) > 1000 mg/L (nominal), EC50 (effect: growth rate) > 1000 mg/L (nominal).

Description of key information

- EC50 (72 h) > 1000 mg/L for Desmodesmus subspicatus (DIN 38412, part 9, static, non-GLP).

- EC10 (72 h) > 1000 mg/L for Desmodesmus subspicatus (DIN 38412, part 9, static, non-GLP).

Key value for chemical safety assessment

EC50 for freshwater algae:
1 000 mg/L
EC10 or NOEC for freshwater algae:
1 000 mg/L

Additional information

The acute toxicity to Desmodesmus subspicatus was determined according to DIN 38412, part 9 test protocol, resulting in EC10 as well as EC50 value greater than 1000 mg/L within 72 hours. These results are related to both biomass gain and growth rate (BASF, 1988).

In a long-term test with Pseudokirchneriella subcapitata a NOEC (14d) of 940 mg/L was found (Hughes & Vilkas, 1988). However, this test is not used for the hazard assessment as the algae growth was no longer in the exponential phase at the end of the test. Only low toxicity to two different algae species (Pseudokirchneriella subcapitata and Chlorella vulgaris) is shown in another study which was conducted by El Jay, A. (1996).