Sulfapyridine

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This is a publication result with a scientific method.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sulfapyridine

EC Number:

205-642-7

EC Name:

Sulfapyridine

Cas Number:

144-83-2

Molecular formula:

C11H11N3O2S

IUPAC Name:

4-amino-N-pyridin-2-ylbenzenesulfonamide

Details on test material:

no data

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
no data

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

no data

Test solutions

Vehicle:

not specified

Test organisms

Test organisms (species):

other: Scenedesmus vacuolatus

Details on test organisms:

A synchronized unicellular limnic green algae Scenedesmus vacuolatus (strain 211-15, SAG (Culture Collection of Algae), Universität Göttingen, Germany) culture was used for this assay. The stock culture was grown under photoautotrophic conditions at 28 °C (±0.5 °C) in an inorganic, sterilized medium (pH 6.4) with saturating white light. The cells were aerated with 1.5 vol.% CO2 and synchronized using a 14-10 h light-darkness cycle. The stock culture was diluted every day to a cell density of 5 x 105 cells/ml.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Test conditions

Hardness:

no data

Test temperature:

28± 0.5 °C

pH:

6.4

Dissolved oxygen:

the test solutions were stirred continuously

Salinity:

no data

Nominal and measured concentrations:

four test concentrations, two replicates for each concentration

Details on test conditions:

The toxicity test started with autospores (young algal cells at the beginning of the growth cycle). The algae were exposed to the test substance for one growth cycle (24 h). The endpoint of this assay is the inhibition of algal reproduction, measured as the inhibition of population growth. Cell numbers were determined with a Coulter Counter Z2 (Beckmann, Germany). The test was performed in sterilized glass tubes, the algae were stirred throughout the 24 h test period, and the test condition was the same as for the stock culture except for the CO2 source. The study was tested at least twice; first, a range finding was undertaken (four concentrations, two replicates); then, the result was verified with eight concentrations in two replicates. The data was pooled for analysis. Growth inhibition was calculated using the cell counts of the treated samples in relation to the untreated controls. At least six controls were used.
This test is a modified version of the assay described by Altenburger et al. (1990), and its sensitivity is comparable to the standardized 72 h test (ISO 8692, 1989).

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.28 mg/L

Conc. based on:

test mat.

Basis for effect:

cell number

Details on results:

The results presented in this study demonstrate that the test substance showed toxic effects to the limnic green algae S. vacuolatus.

Results with reference substance (positive control):

no data

Reported statistics and error estimates:

The confidence interval (a = 0.05) of the EC50 value was calculated using the R language. The dose-response curve parameters and plots were obtained using the drift package (version 0.05-92) for the R language and environment for statistical computing (www.r-pro- ject.org) as well as SigmaPlot Version 10.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 (24 h) was 5.28 mg/l based on the cell number.

Executive summary:

The test was performed to determine the reproduction inhibiton on limnic green algae Scenedesmus vacuolatus with the test duration of 24 hours. The result showed the EC50 (24 h) was 5.28 mg/l based on the cell number.