3-chloroperbenzoic acid

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:

2018-05-24 until 2018-09-28

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2006, Annex 5 corrected 28 July 2011
Procedures also based on the test methods described in OECD series on testing and assessment number 23, 2000

Deviations:

not specified

GLP compliance:

yes

Specific details on test material used for the study:

Identification: 3-Chloroperoxybenzoic acid
Batch: A0378021
Purity/Composition: 98.8% of 3-Chloroperoxybenzoic acid (72%) balanced wtih 3-chlorobenzoic acid (8.8%) and water (18%)
Test item storage: in refrigerator (2-8°C)
Stable under storage conditions utnil retest date of 2018-10-13
CAS number: 937-14-4
Molecular formula: C7H5ClO3
Molecular weight: 172.57
Irritant or corrosive: yes

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Samples (1.8 mL) were taken from all test concentrations (from the approxmiate center of the test vessels) and the control at 0 hours (the start of the exposure), 24 hours, and 72 hours. At the end of exposure, replicates with algae were pooled at each concentration before sampling.
- Sample storage conditions before analysis: Stored in freezer ≤-15°C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The batch of test item was not completely soluble in test medium at the loading rates initially prepared: 1.0, 10, and 100 mg/L No correction was made for the purity/composition of the test item. A 3-day period of magnetic stirring was applied to ensure maximum dissolution of the test item in medium. The Water Accommodated Fractions (WAFs) were collected by filtration through a 0.45 um membrane filter and used as the highest test concentration. Lower test concentrations were prepared by dilutions of the WAF in test medium.
- Differential loading: After preparation, volumes of 50 mL were added to each replicate of teh respective test concentration.
- Controls: test medium
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Algae
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): in-house laboratory culture
- Age of inoculum (at test initiation): cells from algal stock culture were inoculated in culture medium at cell density of 1 x 10^4 cells/mL 3 days before start of test
- Method of cultivation: algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar.

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): yes; M2, according to OECD 201 guideline, formulated with Milli-reverse osmosis water containing the following: 15 mg/L NH4Cl, 12 mg/L MgCl2 6H2O, 18 mg/L CaCL2 2H2O, 15 mg/L MgSO4 7H2O, 1.6 mg/L KH2PO4, 64 ug/L FeCl3 6H2O, 100 ug/L Na2EDTA 2H2O, 185 ug/L H3BO3, 415 ug/L MnCl2 4H2O, 3 ug/L ZnCl2, 1.5 ug/L CoCl2 6H2, 0.01 ug/L CuCl2 2H2O, 7 ug/L Na2MoO4 2H2O, 50 mg/L NaHCO3
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Hardness:

0.24 mmol/L (calcium and magnesium)

Test temperature:

21-24 °C

pH:

8.1±0.2

Dissolved oxygen:

not reported

Salinity:

not applicable

Conductivity:

not reported

Nominal and measured concentrations:

Initial measured concentrations: 0.093, 0.28, 0.85, 2.7, and 8.5 mg/L, at 1.0 3.2, 10, 32, and 100% of the WAF prepared at 10 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL all-glass containers with aluminum caps, perforated for ventilation
- Material, size, headspace, fill volume: 50 mL test solution
- Aeration: continuous
- Initial cells density: 1 x10E4 cells/mL
- Control end cells density: >100x10E4 cells/mL
- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 3, and 1 or 2 replicates of each test concentration without algae, and 1 extra replicate of each test group for sampling purposes after 24 hours of exposure
- No. of vessels per control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: M1: Milli-reverse osmosis water containing 500 mg/L NaNO3, 39.5 mg/L K2HPO4, 75 mg/L NgSO4 7H2O, 20 mg/L Na2CO3, 6 mg/L C6H8O7 H2O, 330 mg/L NH4NO3, 35 mg/L CaCl2 2H2O, 6 mg/L C6H5FeO7 xH2O, 2.9 mg/L H3BO3, 1.81 mg/L Mncl2 4H20, 0.11 mg/L ZnCl2, 0.08 mg/L CuSO4 5H2O, 0.018 mg/L (NH4)6Mo7O24 4H2O
- Intervals of water quality measurement: pH measured at beginning and end of test; temperature measured continuously in a temperature control vessel

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: TLD-lamps with intensity within 87-88 uE.m-2 s-1

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: microscope and counting chamber at start of test; during test, spectrophotometric measurement of samples at 680 nm using a spectrophotometer with immersion prob (path length = 10 mm)


TEST CONCENTRATIONS
- Spacing factor for test concentrations: not specified
- Range finding study
- Test concentrations: 6 replicates of algae were exposed to a control and a WAF prepared at 100 mg/L
- Results used to determine the conditions for the definitive study: yes. The expected EC50 for growth rate inhibition was between concentrations obtained in WAFs at 1.0 and 10 mg/L; the expected EC50 for yield inhibition was below the concentration obtained in a WAF at 1.0 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.093 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

statistical analysis

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.28 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

biological relevance

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.093 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

cell number

Remarks:

statistical analysis

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.093 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

cell number

Remarks:

biological relevance

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.49 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

cell number

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No. Microscopic observations at the end of the test revealed a normal and healthy appearance of algal cells exposed to 0.85 mg/L (10% of the WAF at 10 mg/L) when compared to the control.
- Any stimulation of growth found in any treatment: No. Inhibition of growth rates increased with increasing concentration of test material. Inhibition of yield increased with increasing concentration of test material.

Results with reference substance (positive control):

- Results with reference substance valid? Yes. Algae were exposed for a period of 72 hours to reference substance potassium dichromate concentrations of 0.18, 0.32, 0.56, 1.0, 1.8, 3.2 mg/L and to control. Initial cell density was 1.0 x 10E4 cells/mL.
- EC50: 0.90 mg/L (95% CI 0.88-0.93) (growth rate inhibition). 0.30 mg/L (95% CI 0.29-0.31) (yield inhibition)

Effect parameters

Parameter (mg/L)		NOEC*	NOEC**	EC10	EC20	EC50
Growth rate	Value	0.093	0.28	0.62	0.73	1.0
	Lower 95% confidence limit			0.55	0.69	0.97
	Upper 95% confidence limit			0.67	0.76	1.1
Yield	Value	0.093	0.093	0.22	0.29	0.49
	Lower 95% confidence limit			0.20	0.27	0.47
	Upper 95% confidence limit			0.23	0.31	0.52

*based on statistical significance: the highest tested concentration at which the test item is observed to have no statistically significant reducing effect on growth (at p<0.05) when compared with the control.

**based on biological relevance: the highest tested concentration at which the test item is observed to have no statistically significant reducing effect on growth when compared with the control and has biologically relevant effects (i.e. >10%) on algal growth/yield relative to control values.

Validity criteria fulfilled:

yes

Conclusions:

A dose-related inhibition of algal growth was found and 100% inhibition of both growth rate and yield was observed at 2.7 mg/L and higher. The EC50 based on growth rate was 1.0 mg/L (95% CL 0.97-1.1) and the EC50 based on yield was 0.49 mg/L (95% CL 0.47-0.52). The NOEC for growth rate based on statistical signfiicance was 0.093 mg/L and based on biological relevance was 0.28. The NOEC for yield based on statistical signfiicance or biological relevance was 0.093 mg/L.

Executive summary:

Following OECD guideline 201, 2006 (Annex 5 corrected 28 July 2011), the test substance 3 -chloroperoxybenzoic acid was tested for toxic effects in Psudokirchneriella subcapitata over 72 hours and the inhibition of growth rate and inhibition of yield were determined.

Six replicates of exponentially growing algal cultures were exposed to a control, whereas three replicates per group were exposed to solutions containing 1.0, 3.2, 10, 32 and 100% of the WAF prepared at a loading rate of 10 mg/L. The initial algal cell density was 104 cells/mL and the total exposure period was 72 hours. Samples for analytical confirmation of exposure concentrations were taken at the start, after 24 and 72 hours of exposure. The measured initial concentrations were 0.093, 0.28, 0.85, 2.7, and 8.5 mg/L at 1.0, 3.2, 10, 32 and 100% of the WAF prepared at 10 mg/L.

A dose-related inhibition of algal growth was found and 100% inhibition of both growth rate and yield was observed at 2.7 mg/L and higher. The EC50 based on growth rate was 1.0 mg/L (95% CL 0.97-1.1) and the EC50 based on yield was 0.49 mg/L (95% CL 0.47-0.52). The NOEC for growth rate based on statistical significance was 0.093 mg/L and based on biological relevance was 0.28. The NOEC for yield based on statistical significance or biological relevance was 0.093 mg/L.

Description of key information

Following OECD guideline 201, 2006 (Annex 5 corrected 28 July 2011), the test substance 3 -chloroperoxybenzoic acid was tested for toxic effects in Psudokirchneriella subcapitata over 72 hours and the inhibition of growth rate and inhibition of yield were determined.

Six replicates of exponentially growing algal cultures were exposed to a control, whereas three replicates per group were exposed to solutions containing 1.0, 3.2, 10, 32 and 100% of the WAF prepared at a loading rate of 10 mg/L. The initial algal cell density was 104 cells/mL and the total exposure period was 72 hours. Samples for analytical confirmation of exposure concentrations were taken at the start, after 24 and 72 hours of exposure. The measured initial concentrations were 0.093, 0.28, 0.85, 2.7, and 8.5 mg/L at 1.0, 3.2, 10, 32 and 100% of the WAF prepared at 10 mg/L.

A dose-related inhibition of algal growth was found and 100% inhibition of both growth rate and yield was observed at 2.7 mg/L and higher. The EC50 based on growth rate was 1.0 mg/L (95% CL 0.97-1.1) and the EC50 based on yield was 0.49 mg/L (95% CL 0.47-0.52). The NOEC for growth rate based on statistical significance was 0.093 mg/L and based on biological relevance was 0.28. The NOEC for yield based on statistical significance or biological relevance was 0.093 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

1 mg/L

EC10 or NOEC for freshwater algae:

0.093 mg/L