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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
according to guideline
Guideline:
other: DEV L9
Principles of method if other than guideline:
cell multiplication inhibition test
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
a stock solution was prepared; to achive the test concentrations a defined amount of the stock solution was dissolved
Test organisms (species):
Microcystis aeruginosa
Details on test organisms:
blue-green algae = cyanobacteria
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
8 d
Test temperature:
27°C
pH:
initial pH 7.0
Duration:
8 d
Dose descriptor:
other: TGK
Effect conc.:
13 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: cell multiplication

In the cited literature, the experiments were conducted with the species Microcystis aeruginosa and Scenedesmus quadricauda. In the OECD/ICCA HPV programm it was stated that it is unclear whether the algae S. quadricauda are within the exponential growth throughout the whole exposure period of 8 days. Accordingly, the study was assessed to be not reliable (reliability 3). However, the bluegreen algae Microcystis aeruginosa have a lower rate of reproduction compared to green algae and are still in the exponential growth rate under the experimental conditions after 8 d.

Validity criteria fulfilled:
not specified
Conclusions:
The toxicity of m-cresol to the blue-green algae Microcystis aeruginosa (Cyanaophyceae) was determined in a cell multiplication inhibition test according to the guideline DEV L9. The relevant 8d-NOEC (EC3) for growth rate is 13 mg/L.
Executive summary:

The toxicity of m-cresol to the blue-green algae Microcystis aeruginosa (Cyanaophyceae) was determined in a cell multiplication inhibition test according to the guideline DEV L9. The relevant 8d-NOEC (EC3) for growth rate is 13 mg/L.

Description of key information

The toxicity of m-cresol to the blue-green algae Microcystis aeruginosa (Cyanaophyceae) was determined in a cell multiplication inhibition test according to the guideline DEV L9. The relevant 8d-NOEC (EC3) for growth rate is 13 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
13 mg/L

Additional information

Concerning toxicity to aquatic algae there is one study using m-cresol as test substance available.

The toxicity of m-cresol to the blue-green algae Microcystis aeruginosa (Cyanaophyceae) was determined in a cell multiplication inhibition test according to the guideline DEV L9. Test conditions were as follows: continuous light, 27°C, with or without neutralization. The pH of the neutralized test solution was 7. For the endpoint biomass at the end of the test an 8 day-toxicity threshold value of 13 mg/l was obtained (nominal concentration). This toxicological threshold can also be regarded as a NOEC- or an EC3-value. For this reason the NOEC value can be given as 13 mg/l.