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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
Study period:
72 hours
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
Performed 2002 to GLP following accepted guidelines, but no supporting analysis
The substance is supplied in water and is considered to be stable.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
Seawater type
GLP compliance:
yes
Specific details on test material used for the study:
Note, this is described as thiourea polyimidazoline, CAS 62-56-6.
Water based commercial product and results axpressed material supplied not actives.
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Skeletonema costatum
Test type:
static
Water media type:
saltwater
Limit test:
no
Total exposure duration:
72 h
Hardness:
Seawater used
Test temperature:
17.6 - 21.5
pH:
10.1
Salinity:
Natural seawater
Details on test conditions:
Range : 0, 100, 300, 900, 2700 mg/l based on material supplied at ca 50% actives
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Duration:
72 h
Dose descriptor:
IC50
Effect conc.:
ca. 1 400 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Remarks:
ca 50% commercial grade
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
IC50
Effect conc.:
ca. 700 mg/L
Nominal / measured:
estimated
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 300 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
At the maximum concentration of 2700 mg/l (1350 mg/l actives) there was 100% inhibition.
Validity criteria fulfilled:
not specified
Conclusions:
The substance does not need to be classified on the basis of this result.
Although there was no analysis and some key data seem to be missing from the report, the study was performed to guidelines and reported in sufficient detail to conclude that although inhibition of algal growth takes place at high concentrations, the effect levels are significanlty greater than limits for classification.

Description of key information

The reported IC50 for marine algae is 1400 mg/l based on the test material which was the nominal 50% active commercial grade supplied in water.

The figure used for the CSR is based on the actives at 700 mg/l

Key value for chemical safety assessment

EC50 for marine water algae:
700 mg/L
EC10 or NOEC for marine water algae:
150 mg/L

Additional information