Benzenesulfonamide, N-(4-hydroxyphenyl)-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
[Describe why the read-across can be performed (e.g. common functional group(s), common precursor(s)/breakdown product(s) or common mechanism(s) of action]
See attached documents.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]
See attached documents.

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]
See attached documents.

4. DATA MATRIX
See attached documents.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 4.06-6.51 mg/L (95M)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.94 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 0.75-1.23 (95%)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: and yield

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1.41 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and yield

Details on results:

/

Results with reference substance (positive control):

/

Validity criteria fulfilled:

yes

Conclusions:

The toxicity to P. subcapitata was determined using read-across from a structural analogue.
EC50 (72h - Pseudekirchneriella subcapitata) = 5.19 mg/L (growht rate) ; 0.94 mg/L (yield).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Samples were taken from the control and each test group from the bulk test preparation at 0 hours and from the pooled replicates at 72 hours for quantitative analysis. All samples were stored frozen prior to analysis. Duplicate samples were taken at 0 and 72 hours and stored frozen for further analysis if necessary.

Details on test solutions:

the test item was categorized as being a ‘difficult substance’ as defined by the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD 2000). Therefore a media preparation trial was conducted in order to determine the solubility of the test item under test conditions. This indicated that a dissolved test item concentration of approximately 68 mg/L could be obtained using a satured solution method of preparation.
A series of dilutions was made from this saturated solution to give stock solutions of 32, 10, 3.2, 1.0, 0.32 and 0.10% v/v saturated solution. An aliquot (450 mL) of each of the stock solutions was separately inoculated with 1.9 mL of algal suspension to give the required test concentrations of 0.10, 0.32, 1.0, 3.2, 10 and 32% v/v saturated solution.

Test organisms (species):

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

Details on test organisms:

Pseudokirchneriella subcapitata strain CCAP 278/4. Liquid cultures were obtained from CCAP, SAMS Research Services Ltd., Scottish Marine Institue, Oban, Argyll, Scotland. Master cultures were maintained in the laboratoty by the periodic repelenishment of culture medium under constant aeration and constant illumination at 21 +- 1 °C.

Prior to the start of the test sufficient master culture was added to approx 10 mL volumes of culture media contained in conical flasks to give an initial cell densitiy of approx 10^3 cells/ml. The flasks were plugged with polyurrethane foam stoppers and kept under constant agitation by orbital shaker (100 - 150 rpm) and constant illumination at 24 +- 1 °C until the algal density was approximately 10^4-10^5 cells/ml

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Post exposure observation period:

None

Hardness:

no data

Test temperature:

21 ± 1 °C

pH:

7.3-7.7
7.8 control

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

nominal concentrations of 0.10, 0.32, 1.0, 3.2, 10 and 32% v/v saturated solution

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flasks plugged with polyurethan foam stoppers, kept under constant agitation by orbital shaker (100-150 rpm) and constant illumination at 24+-°C.
- Initial cells density: 1000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
NaNO3 25.5 mg/L
MgCl2.6H2O 12.16 mg/L
CaCl2.2H2O 4.41 mg/L
MgSO4.7H2O 14.6 mg/L
K2HPO4 1.044 mg/L
NaHCO3 15.0 mg/L
H3BO3 0.186 mg/L
MnCl2.4H2O 0.415 mg/L
ZnCl2 0.00327 mg/L
FeCl3.6H2O 0.160 mg/L
CoCl2.6H2O 0.00143 mg/L
Na2MoO4.2H2O 0.00726 mg/L
CuCl2.2H2O 0.000012 mg/L
Na2EDTA.2H2O 0.30 mg/L
The culture medium was prepared using reverse osmosis purified deionized water* and the pH adjusted to 7.5 with 0.1N NaOH or HCl.

OTHER TEST CONDITIONS
- Adjustment of pH: pH adjusted to 7.5 with 0.1N NaOH or HCl
- Photoperiod: constant illumination at 24+-°C

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Coulter® Multisizer Particle Counter

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 4.3-6.9 mg/L (95M)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 0.79-1.3 (95%)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.32 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: and yield

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and yield

Details on results:

/

Results with reference substance (positive control):

/

Reported statistics and error estimates:

One way analysis of variance incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf, 1981) and Dunnett's multiple comparison procedure for comparing several treatments with a control (Dunnett, 1955) was carried out on the growth rate and yield data after 72 hours for the control and all test concentrations to determine any statistically significant differences between the test and control groups. All statistical analyses were performed using the SAS computer software package (SAS, 1999 - 2001).

Validity criteria fulfilled:

yes

Conclusions:

EC50 (72h - Pseudekirchneriella subcapitata) = 5.5 mg/L (growht rate) ; 1.0 mg/L (yield).

Description of key information

Para-tosylcatechol (CAS: 107065-85-0) is a similar substance and the test results can be used for read-across: EC50 (72h - Pseudekirchneriella subcapitata) = 5.5 mg/L (growht rate)

Key value for chemical safety assessment

EC50 for freshwater algae:

5.19 mg/L