N-phenyl-N'-[(phenylamino)sulfonyl]urea

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:

15.03.-09.04.16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

2006

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-phenyl-3-(phenylsulfamoyl)urea

EC Number:

813-358-5

Cas Number:

4886-26-4

Molecular formula:

C13H13N3O3S

IUPAC Name:

1-phenyl-3-(phenylsulfamoyl)urea

Test material form:

solid: particulate/powder

Details on test material:

- State of aggregation:
- Particle size distribution:
- Mass median aerodynamic diameter (MMAD):
- Geometric standard deviation (GSD):
- Shape of particles:
- Surface area of particles:
- Crystal structure:
- Coating:
- Surface properties:
- Density:
- Moisture content:
- Residual solvent:
- Activation:
- Stabilisation:
- Other:

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain:
- Source (laboratory, culture collection): Culture Collection of Algae at the University of Goettingen, Germany
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

23.2 - 23.6 °C

pH:

7.5 - 7.5 in the control and 7.5 - 7.7 in the test concentration

Nominal and measured concentrations:

nominal (limit test):174.6 mg/L
meaured (limit test): 98.5 – 101.9 % of the nominal loading rate and stable during the exposure period

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

174.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 144.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

ErC50 of 0,831 mg/L (CI 95 %: 0,790 - 0,869 mg/L) and, therefore, is within the required range of 0.6 - 1.08 mg/L. The EyC50

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test item shows a low toxicity to algae. The NOEC is calculated >= 144.9 mg/L.

Executive summary:

Static algal growth inhibition tests with D. subspicatus were performed using maximum concentrated stock solutions (limit of solubility) with a loading rate of 200 mg/L test item. A standard test (5 test item concentrations) did not comply with all criteria of validity. As none of the test item concentrations showed inhibition of algal growth, a second test was conducted as limit test (1 test item concentration). The measured test item concentration of the stock solution at the start of the test (0 h) is used as the highest “nominal” concentration and the lower “nominal” concentrations are calculated using the corresponding concentration factors. As the measured concentrations are within ± 20 % of the “nominal” concentrations, according to OECD 201, all results are given in relation to the “nominal” test item concentrations:

Standard test

• LOEC > 144.9 mg/L test item, NOEC ≥ 144.9 mg/L test item, for yield and growth rate

The test did not comply with all three criteria of validity because the mean coefficient of variation for section-by-section specific growth rate in the control cultures was 39.3 % and, thus, higher than the limit of ≤ 35 % according to OECD 201. However, results are meaningful and relevant. The measured test item concentrations in the test treatments were 97.4 - 103.3 % of the “nominal” test item concentration and stable during the exposure period. The concentrations in the control were below the limit of quantification.

Limit test

•A statistically significant difference between control and 174.6 mg/L test item was demonstrated for yield and growth rate.

• The test is valid according to OECD Test Guideline 201 (March 2006).

The measured test item concentrations in the test treatments were 98.5 - 101.9 % of the “nominal” test item concentration and stable during the exposure period. The concentrations in the control were below the limit of quantification.

Overall results

NOEC ≥ 144.9 mg/L test item for growth rate and yield; LOEC = 174.6 mg/L test item, for growth rate and yield (corresponding to an inhibition of 6.8 % and 18.0 %, respectively)