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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:
September 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)
Deviations:
not specified
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
Test substance: Triazolone
CAS#: 930-33-6
Stability: stable
Solubility: soluble in seawater
Appearance: white solid, powder with no odour
Date received: 01.09.2006
Storage: 20°C
Analytical monitoring:
not specified
Details on sampling:
none
Vehicle:
no
Details on test solutions:
Dissolve the test substance in the culture medium. The concentration of this stock solution should correspond with the highest test dosage.
Mix the stock solution in a 1L glassflask on a magnetic stirrer for at least 30 min.

Based on the results from the preliminary test, the following test dosages were used for the definitive test: 2.0, 10, 50, and 250 mg/L
Test organisms (species):
Skeletonema costatum
Details on test organisms:
Strain NIVA BAC 1 was used.
Test type:
static
Water media type:
saltwater
Limit test:
yes
Total exposure duration:
72 h
Hardness:
not specified
Test temperature:
20 +/- 2.4 °C
pH:
7.5 - 8.3
Salinity:
NA
Conductivity:
not specified
Nominal and measured concentrations:
nominal concentrations: 2.0, 10, 50, and 250 mg/L
Details on test conditions:
Two tests were performed. A preliminary test with 2 parallel test concentrations, followed by a definitive test wtih 3 parallel concentrations and 6 controls.
Inhibition is measured as a reduction in growth rate relative to control cultures grown under identical conditions.
light intensitiy has been in the range 6000-10000 lux.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 18 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
none
Results with reference substance (positive control):
growth rate inhibition of 1.5 mg/L 3,5-dichlorophenol = 24%
Reported statistics and error estimates:
none

none

Validity criteria fulfilled:
yes
Conclusions:
The 72hEC50 for triazolone was found to be 18 mg/L.
The NOEC value was estimated to 2.0 mg/L.
Executive summary:

S. costatum testing has been performed on the test substance TO Triazolone base on ISO 10253.

The EC50 -value found for the test substance TO Triazolone (nominal whole product) after 72h was 18 mg/L. The EC10 was estimated to 4.2 mg/L, and the NOEC value was estimated to 2.0 mg/L.

Description of key information

Data based on experimental study results.

S. costatum testing has been performed on the test substance TO Triazolone base on ISO 10253.

The EC50 -value found for the test substance TO Triazolone (nominal whole product) after 72h was 18 mg/L. The EC10 was estimated to 4.2 mg/L, and the NOEC value was estimated to 2.0 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
18 mg/L

Additional information