sodium 4-[(4-chlorobenzoyl)amino]benzoate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

sodium 4-[(4-chlorobenzoyl)amino]benzoate

EC Number:

807-461-4

Cas Number:

1489170-67-3

Molecular formula:

C14H9ClNNaO3

IUPAC Name:

sodium 4-[(4-chlorobenzoyl)amino]benzoate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Storage condition of test material: room temperature in the dark
- Description: white powder

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100% v/v saturated solution test preparations (nominal)
- Sample storage conditions before analysis: The samples were stored frozen prior to analysis
- Preparation of Calibration Standards:
The test item (nominal 100 mg) was dissolved in 0.1 % (v/v) formic acid in methanol (100 mL) to prepare a stock solution with a nominal concentration of 1000 mg/L. This stock solution was further diluted with 0.1 % (v/v) formic acid in methanol to obtain a nominal 10 mg/L calibration standard. A duplicate calibration standard was similarly prepared at 10 mg/L. These duplicate calibration standards were used to determine the recovery and test sample concentrations.
- Preparation of Linearity Standards:
The test item (nominal 100 mg) was dissolved in 0.1 % (v/v) formic acid in methanol (100 mL) to prepare a stock solution with a nominal concentration of 1000 mg/L. Defined volumes of this stock solution were diluted with 0.1 % (v/v) formic acid in methanol to obtain standards in the range of 0.10 to 100 mg/L. A second standard was similarly prepared at a nominal concentration of 10 mg/L. These standards were used to evaluate the linearity of the analytical system.
- Preparation of Spiked Recovery Samples:
To demonstrate the validity of the analytical procedure, volumes of test medium were spiked with the test item and the recovery was assessed. The test item (nominal 100 mg) was initially dissolved in 0.1 % (v/v) formic acid in methanol to prepare a stock solution with a concentration of 1000 mg/L. This stock solution was further diluted with 0.1 % (v/v) formic acid to produce a stock solution of 200 mg/L. A defined volume of this stock solution was diluted with test medium to obtain spiked recovery samples at a concentration of 0.10 mg/L. Five replicates were prepared and subjected to the same treatment as the test samples. In addition, test medium without the addition of the test item (synthetic control) was also analysed.
- Preparation of Test Samples:
The test samples were thawed with the aid of sonication. The test item was extracted from the test samples using a solid phase extraction cartridge (strata C18-E, 500 mg/ 3 mL). The cartridge was pre-conditioned with 10 mL of 0.1 % (v/v) formic acid in methanol and 10 mL of water. The samples were drawn through the cartridge under reduced pressure. Subsequently, the cartridge was eluted with approximately 20 mL of 0.1 % (v/v) formic acid in methanol into a 20 mL volumetric flask. The solution was made up to the mark with 0.1 % (v/v) formic acid in methanol. See Table 1 for more information on preparation volumes.

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing.
A preliminary media preparation trial indicated that a dissolved test item concentration of approximately 11 mg/L was obtained from a saturated solution method of preparation indicating this to be the limit of water solubility of this item under test conditions.
The test item solutions were prepared by stirring an excess (100 mg/L) of test item in test water using a propeller stirrer at approximately 1500 rpm for 24 hours. After the stirring period any undissolved test item was removed by filtration (0.2 µm Sartorius Sartopore filter, first approximate 1 L discarded in order to pre-condition the filter) to produce a 100% v/v saturated solution of the test item. A series of dilutions was made from this saturated solution to give further test concentrations of 10, 1.0 and 0.10% v/v saturated solution. The stock solutions and each of the prepared concentrations were inverted several times to ensure adequate mixing and homogeneity.
Based on the results of the range-finding test the following test concentrations were assigned to the definitive test: 0.10, 0.32, 1.0, 3.2 and 10% v/v saturated solution.
- Controls: The control group was maintained under identical conditions but not exposed to the test item.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Reconstituted water (ISO medium) used for both the range-finding and definitive test

Test organisms

Test organisms (species):

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

Details on test organisms:

The test was carried out using Pseudokirchneriella subcapitata strain CCAP 278/4. Liquid cultures of Pseudokirchneriella subcapitata were obtained from the Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd, Scottish Marine Institute, Oban, Argyll, Scotland. Master cultures were maintained in the laboratory by the periodic replenishment of culture medium. The master cultures were maintained in the laboratory under constant aeration and constant illumination at 21 ± 1 °C.
Prior to the start of the test sufficient master culture was added to approximately 100 mL volumes of culture media contained in conical flasks to give an initial cell density of approximately 103 cells/mL. The flasks were plugged with polyurethane foam stoppers and kept under constant agitation by orbital shaker (100- 150 rpm) and constant illumination at 24 ± 1 °C until the algal cell density was approximately 104 - 105 cells/mL.
The culture medium used for both the range-finding and definitive tests was the same as that used to maintain the stock culture.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

24 ± 1 °C

pH:

range from pH 7.9 at 0 hours to pH 7.1 at 72 hours

Nominal and measured concentrations:

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

Details on test conditions:

see "Any other information on materials and methods incl. tables"

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 1.3 - 1.4 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.51 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1.3 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.91 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 95% CL: 0.82 - 1.0 mg/L

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.51 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

1.3 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: yield

Results with reference substance (positive control):

A positive control used potassium dichromate as the reference item at concentrations of 0.25, 0.50, 1.0, 2.0 and 4.0 mg/L.
Exposure conditions for the positive control were similar to those in the definitive test.
Exposure of Pseudokirchneriella subcapitata (CCAP 278/4) to the reference item gave the following results:
ErC50 (0-72h) = 1.2 mg/L; 95% confidence limits 1.1-1.4 mg/L
EyC50 (0-72h) = 0.63 mg/L; 95% confidence limits 0.57 - 0.70 mg/L
No Observed Effect Concentration (NOEC) based on growth rate: 0.50 mg/L
No Observed Effect Concentration (NOEC) based on yield: 0.25 mg/L
Lowest Observed Effect Concentration (LOEC) based on growth rate: 1.0 mg/L
Lowest Observed Effect Concentration (LOEC) based on yield: 0.50 mg/L
The results from the positive control with potassium dichromate were within the normal ranges for this reference item (ErC50 values in the range of 0.82 - 1.4 mg/L obtained between 2010 and 2014).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

A reliability of Klimisch 1 has been assigned as the acute toxicity of the test substance to aquatic algae has been determined in a GLP test with Pseudokirchneriella subcapitata (CCAP 278/4) according to OECD Guideline 201 and EU method C.3. Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.046 to 3.5 mg/L. Analysis of the test preparations at 72 hours showed measured test concentrations to be within 80-120% of the 0-Hour measured test concentrations with the exception of the 0.10% v/v saturated solution test group where a measured concentration of 78% of the 0-Hour measured concentration was obtained. Given that this test concentration was below the No Observed Effect Concentration (NOEC), it was considered appropriate to calculate the results based on the 0-Hour measured test concentrations only.
The growth rate (r) and yield (y) were adversely affected by the presence of the test item over the 72-hour exposure period, accordingly the following results were determined from the data:
Growth rate
ErC50 (0-72 h) : 1.4 mg/L; 95% confidence limits 1.3 - 1.4 mg/L
NOEC = 0.51 mg/L, LOEC = 1.3 mg/L

Yield
EyC50 (0-72 h) : 0.91 mg/L; 95% confidence limits 0.82- 1.0 mg/L
NOEC = 0.51 mg/L, LOEC = 1.3 mg/L

The substance does not need to be classified as Aquatic Acute Cat. 1, as the ErC50 (72h) is > 1 mg/L. Further, although the ErC50 (72h) is >1 and ≤10 mg/L, the substance does not need to be classified as Aquatic Chronic Cat. 2, as it is rapidly degradable and the log Pow is < 4 (criteria for substances for which adequate chronic toxicity data are not available).

All validation criteria have been fulfilled:
The cell concentration of the control cultures increased by a factor of 188 after 72 hours, this increase was in line with the OECD Guideline that states the enhancement must be at least by a factor of 16 after 72 hours.
The mean coefficient of variation for section by section specific growth rate for the control cultures was 9% and hence satisfied the validation criterion given in the OECD Guideline which states the mean must not exceed 35%.
The coefficient of variation for average specific growth rate for the control cultures over the test period (0 - 72 h) was 3% and hence satisfied the validation criterion given in the OECD Guideline which states that this must not exceed 7%.