Diphenyl sulphide

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:

08.09.2017 – 11.09.2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result using OECD guidelines.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

The freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance Diphenyl sulphide (CAS No. 139-66-2) according to OECD Guideline 201.

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No. of test material: No data
- Expiration date of the lot/batch: No data
- Purity test date: No data

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: No data
- Specific activity: No data
- Locations of the label: No data
- Expiration date of radiochemical substance: No data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: No data
- Stability under test conditions: No data
- Solubility and stability of the test substance in the solvent/vehicle: No data
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The stock solution 10.0 g/L was prepared by dissolving light yellow liquid in acetone.

Analytical monitoring:

no

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The stock solution 10.0 g/L was prepared by dissolving light yellow liquid in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Age of inoculum (at test initiation): 5.0x10E3 cells/ml
- Method of cultivation: No data

ACCLIMATION
- Acclimation period: No data
- Culturing media and conditions (same as test or not): No data
- Any deformed or abnormal cells observed: No data

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

±1 hour

Post exposure observation period:

No data

Hardness:

No data

Test temperature:

23°C ± 2°C

pH:

The sample at concentration 3.2 mg/L : pH = 7.9 changed to pH = 7.7 during the test,
Control : pH = 8.0 changed to pH = 7.6 during the test
Control + acetone: pH = 7.9 changed to pH = 7.5 during the test

Dissolved oxygen:

No data

Salinity:

No data

Conductivity:

No data

Nominal and measured concentrations:

0, 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50ml glass vessel
- Type : closed (with air-permeable stopper)
- Material, size, headspace, fill volume: 15 ml
- Aeration: No data
- Type of flow-through (e.g. peristaltic or proportional diluter): No data
- Renewal rate of test solution (frequency/flow rate): No data
- Initial cells density: 5x10E3 cells/ml
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: Without adjustment
- Photoperiod: Continuous
- Light intensity and quality: 6000 lx - 8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Microscope with counting chamber Cyrus I or electronic particle counters.
- Chlorophyll measurement: No
- Other: ErC50 was calculated using non-linear regression by the software Prism 4.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 1.0 to 1.3 mg/L

Details on results:

No data

Results with reference substance (positive control):

Results with reference substance valid
- ErC50: 0.77 mg/L K2Cr2O7

Reported statistics and error estimates:

No data

Control Solution: OECD growth medium without the sample, the coefficient of variation of average growth rate in replicates during the whole test period was 2.8 % in control and 3.3 % in control + acetone.

Validity criteria fulfilled:

yes

Conclusions:

The median effective concentration (ErC50) for the test substance, Diphenyl sulphide, in a freshwater algae Desmodesmus subspicatus was determined to be 1.1 mg/L with 95% confidence limit of 1.0 - 1.3 mg/L on the basis of effects on growth rate in a 72 hour study.

Executive summary:

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance Diphenyl sulphide (CAS No. 139-66-2) according to OECD Guideline 201.

The stock solution 10.0 g/L was prepared by dissolving light yellow liquid in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations of 0, 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg/L. Effects on the growth rate of the organism were studied. The test was performed under static conditions in a fresh water system at a temperature of 23 °C ± 2 °C. EC50 was calculated.

The median effective concentration (ErC50) for the test substance, Diphenyl sulphide, in Desmodesmus subspicatus was determined to be 1.1 mg/L with 95% confidence limit of 1.0 - 1.3 mg/L and also the substance was determine to be not rapidly degradable. Thus, it can be concluded that Diphenyl sulphide (CAS No. 139-66-2) exhibits toxicity to aquatic algae (Desmodesmus subspicatus) in the ''chronic 2'' classification category, criteria of CLP.

Description of key information

The median effective concentration (ErC50) for the test substance, Diphenyl sulphide, in a freshwater algae Desmodesmus subspicatus was determined to be 1.1 mg/L with 95% confidence limit of 1.0 - 1.3 mg/L on the basis of effects on growth rate in a 72 hour study.

Key value for chemical safety assessment

EC50 for freshwater algae:

1.1 mg/L

Additional information

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance Diphenyl sulphide (CAS No. 139-66-2) according to OECD Guideline 201.

The stock solution 10.0 g/L was prepared by dissolving light yellow liquid in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations of 0, 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg/L. Effects on the growth rate of the organism were studied. The test was performed under static conditions in a fresh water system at a temperature of 23 °C ± 2 °C. EC50 was calculated.

The median effective concentration (ErC50) for the test substance, Diphenyl sulphide, in Desmodesmus subspicatus was determined to be 1.1 mg/L with 95% confidence limit of 1.0 - 1.3 mg/L and also the substance was found to be not rapidly degradable. Thus, it can be concluded that Diphenyl sulphide (CAS No. 139-66-2) exhibits toxicity to aquatic algae (Desmodesmus subspicatus) in the ''chronic 2'' classification category, criteria of CLP.