N-(2-hydroxypropyl)benzenesulphonamide

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08/08/2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

24 mg CaCO3 /L

Dissolved oxygen:

no data

Nominal and measured concentrations:

100,10000 mg/L Nominal
measured 88.57 and 9543.58 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml, all-glass
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: /
- Aeration: /
- Type of flow-through (e.g. peristaltic or proportional diluter): /
- Renewal rate of test solution (frequency/flow rate):/
- Initial cells density: 1*10E4 cells/ml
- Control end cells density: at the beginning of the test, cells were counted by microscope, using a counting chamber. Thereafter cell densities were determined by spectrophotometric measurement of samples at 720 nm using a Varian Cary 50 single beam spectrophotometer with immersion probe.
- No. of organisms per vessel:/
- No. of vessels per concentration (replicates):/
- No. of vessels per control (replicates):/
- No. of vessels per vehicle control (replicates):/


GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:tap water purified by reverse osmosis and then passed over activated carbon and ion-exchange cartridges.
- Total organic carbon:/
- Particulate matter:/
- Metals:/
- Pesticides:/
- Chlorine:/
- Alkalinity:/
- Ca/mg ratio: hardness: 0.24 mmol/l
- Conductivity:/
- Culture medium different from test medium:/
- Intervals of water quality measurement: /


OTHER TEST CONDITIONS
- Sterile test conditions: yes/
- Adjustment of pH:/
- Photoperiod:continuously
- Light intensity and quality: TLD-lamps of the type 'cool-white' of 30 watt (Sylvania), with a light intensity within the range of 60 to 120 µE.m-2.s-1, not varying by more than 202%.
- Salinity (for marine algae):/


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber
- Chlorophyll measurement:/
- Other: NH4Cl: 15 mg/l
MgCl2.6H2O: 12 mg/l
CaCl2.2H2O: 18 mg/l
MgSO4.7H2O: 15 mg/l
KH2PO4: 1,6 mg/l
FeCl3.6H2O: 80 µg/l
Na2EDTA.2H2O: 100 µg/l
MnCl2.4H2O: 415 µg/l
ZnCl2: 3µg/l
CoCl2.6H2O: 1,5 µg/l
CuCl2.2H2O: 0,01 µg/l
Na2MoO4.2H2O: 7µg/l
NaHCO3: 50 mg/l


TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline: /
- Range finding study
- Test concentrations: a range of 0,1 to 100 mg/l, increasing by a factor 10.
- Results used to determine the conditions for the definitive study:based on the result of the range-finding test the EC50 for effects on algal growth was expected to lie between 10 and 100 mg/l.

Reference substance (positive control):

yes

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 2 340 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Unusual cell shape:
- Colour differences:
- Flocculation:
- Adherence to test vessels:
- Aggregation of algal cells:
- Other:
- Any stimulation of growth found in any treatment:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium:no

Validity criteria fulfilled:

yes

Conclusions:

The EC50 for cell growth inhibition (EC50: 0-72h) was 2340 mg/l
As the concentrations of N-(hydroxypropyl)benzene sulphonamide measured by HPLC remains within 80-120 of the nominal concentration, the result are based on nominal concentrations

Description of key information

The result of a range finding study was >1000 mg/kg

The 72 h Algae Pseudokirchneriella subcapitata EC 50 =2340 mg/kg

Key value for chemical safety assessment

EC50 for freshwater algae:

2 340 mg/L