Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

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
Details on test conditions:
-stock solution for test medium: 248 mg NaNO3, 19.5 mg K2HPO4, 750 mg MgSO4 x 7 H2O, 360 mg CaCl2 x 2 H2O,
400 mg NaSiO3, 580 mg Na2CO3, 30 mg citric acid, 30 mg ferric (III) citrate, 100 mg Na2EDTA x 2 H2O dissolved in 1 l double-distilled water containing the trace elements as H3BO3, MnCl2, ZnSO4, CuSO4, Na2MoO4 and CoCl2.
-incubation of 10 ml test solution
-the experiment was carried out in duplicate dilution series
-the concentration of the algal suspension was measured turbidimetrically
Duration:
8 d
Dose descriptor:
other: TGK
Effect conc.:
6.8 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: cell multiplication
Details on results:
TGK = Toxicity threshold, determined at 1% effect compared to control

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 o-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) is 6.8 mg/L.
Executive summary:

The toxicity of o-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 6.8 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 6.8 mg/l.

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: Test procedure in accordance with national standard methods with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
other: NEN-6506 (1980)
GLP compliance:
not specified
Analytical monitoring:
no
Vehicle:
not specified
Test organisms (species):
Selenastrum sp.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Test temperature:
26 +/- 3°C
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
75 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Validity criteria fulfilled:
not specified
Conclusions:
With a growth inhibition test according to NEN-6506 (1980) on alga Selenastrum sp. a 96-hour EC50 of 100 mg/L based on nominal concentrations was determined for o-cresol.
Executive summary:

With a growth inhibition test according to NEN-6506 (1980) on alga Selenastrum sp. a 96-hour EC50 of 100 mg/L based on nominal concentrations was determined for o-cresol.

Description of key information

The toxicity of o-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) is 6.8 mg/L .

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
6.8 mg/L

Additional information

Concerning toxicity to aquatic algae there are several tests towards various species using o-cresol as test substance available.

The lowest toxicity value obtained with a blue-green algae is taken into account for further assessment.

The toxicity of o-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 6.8 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 6.8 mg/l.

With a growth inhibition test according to a dutch national standard method NEN-6506 (1980) on alga Selenastrum sp. a 96-hour EC50 of 100 mg/L based on nominal concentrations was determined for o-cresol.