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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Jan-Feb 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study conducted under GLP conditions and in acc. with OECD guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2,6-difluoro-3-(propane-1-sulfonamido)benzoic acid
EC Number:
700-740-0
Cas Number:
1103234-56-5
Molecular formula:
C10H11F2NO4S
IUPAC Name:
2,6-difluoro-3-(propane-1-sulfonamido)benzoic acid
Details on test material:
-Substance type: organic
-Physical state: solid

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
Standard solutions were prepared in acetonitrile, not in the mobile phase. This had
no influence on the test results.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Test type:
static
Water media type:
not specified
Limit test:
yes
Total exposure duration:
72 h

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 82.4 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 82.4 mg/L
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 80.8 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 80.8 mg/L
Basis for effect:
biomass

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

The median growth inhibiting concentrations (ErC50/EyC50) based on the average specific growth rate and the yield (algal biomass production) within 3 days, of SAC­ Sulfonamidsaure to the green alga Desmodesmus subspicatus were investigated over a period of 72 h. 3 parallel test vessels were used for each tested concentration of the test substance.

In the first definitive test with 100 mg/1 nominal concentration a small but statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated controls was observed.

In this first test a time weighted average concentration of 82.4 mg/1 was measured. Hence, the concentration of SAC-Sulfonamidsaure was stable during the test.

Because significant effects were observed, a second test with 50, 70.7 and 100 mg/1 nominal concentration was performed. In this second definitive test no statistically significant growth inhibition with respect to algal growth rates and algal yield (biomass production) compared to the untreated controls was observed at all concentrations.

In this second test time weighted average concentrations of 46.5, 62.7 and 80.8mg/l were measured for the nominally applied concentrations of 50, 70.7 and 100 mg/1, respectively. Hence, the concentration of SAC-Sulfonamidsaure was stable during the test. Based on the results of the study it can be concluded that the ErC50 (0-72 h) and the EyC50 (0-72 h) as well as the low effect concentrations ErC10, ErC20 and EyC1o. EyC2o of SAC-Sulfonamidsaure to Desmodesmus subspicatus were >82.4 mg/1.

Based on the STUDENT-t test for homogeneous variances the no-observed-effect concentrations for growth rates (NOErC) and yield (NOEyC) of SAC­ Sulfonamidsaure were <82.4 mg/L in the first definitive test and >80.8 mg/L in the second definitive test. Hence, the overall no-observed-effect concentrations for growth rate (NOErC) and yield (NOEyC) of SAC-Sulfonamidsäure were 80.8 mg/L.