3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

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:

10-04-2017 - 13-04-2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result performed using standard test guidelines.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Specific details on test material used for the study:

- Name of the test material: 3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one
- Molecular formula: C28H30N2O3
- Molecular weight: 442.556 g/mol
- Substance type: Organic
- Smiles: C12(c3c(Oc4c1ccc(c4)N(CC)CC)cc(N(CC)CC)cc3)c1c(cccc1)C(O2)=O

Analytical monitoring:

not specified

Vehicle:

yes

Details on test solutions:

The stock solution (100 mg/L) was prepared by dissolving pinkish red powder in DMSO/ OECD growth medium. The stock solution was kept in ultrasonic bath for 20min Test solutions of required concentration 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
- Common name:
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Initial biomass concentration: 5x10(3) cells /ml
- Method of cultivation: No data available

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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

±1 hour

Hardness:

Not specified

Test temperature:

23±2°C

pH:

WIthout adjustment
The sample at concentration 40 mg/l: pH=8 changed to 7.9 during the test
Control: pH= 8.1 changed to pH= 7.5 during the test

Dissolved oxygen:

Not specified

Salinity:

Not specified

Conductivity:

Not specified

Nominal and measured concentrations:

0, 2.5, 5, 10, 20 and 40 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type (delete if not applicable): closed (with air permeable stopper)
- Sample volume: 15 ml
- Initial cells density: 5x10(3) cells/ml
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: 6000-8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: microscope with counting chamber Cyrus I or electronic particle counter.
- 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.:

13.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 11.9 - 15.2

Results with reference substance (positive control):

Results with reference substance valid
- EC50: 0.75 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The median effective concentration (EC50) for the test substance, 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one, in Desmodesmus subspicatus was determined to be 13.4 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 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one according to OECD Guideline 201.

The test substance was dissolved in DMSO/ OECD growth medium and tested at the concentrations 0, 2.5, 5, 10, 20 and 40 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (EC50) for the test substance, 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one, in Desmodesmus subspicatus was determined to be13.4 mg/L.

This value indicates that the substance is likely to be hazardous to aquatic algae and can be classified as Aquatic Chronic 3 as per the CLP criteria.

Description of key information

The median effective concentration (EC50) for the test substance, 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one, in Desmodesmus subspicatus was determined to be 13.4 mg/L on the basis of effects on growth rate in a 72 hour study. This value indicates that the substance is likely to be hazardous to aquatic algae and can be classified as Aquatic Chronic 3 as per the CLP criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

13.4 mg/L

Additional information

Various studies, considering its adequacy as one key and other supporting, were reviewed for the endpoint short term toxicity to aquatic algae of the substance 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one and same are summarized as below:

In key study, Freshwater algal growth inhibition test was carried out by SSS on Desmodesmus subspicatus with the substance 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one according to OECD Guideline 201. The test substance was dissolved in DMSO/ OECD growth medium and tested at the concentrations 0, 2.5, 5, 10, 20 and 40 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (EC50) for the test substance, 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one, in Desmodesmus subspicatus was determined to be 13.4 mg/L. This value indicates that the substance is likely to be hazardous to aquatic algae and can be classified as Aquatic Chronic 3 as per the CLP criteria.

The above experimental result was supported by yet another study carried out by SSS in which the effect of test item 3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, CAS No. 509-34-2 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.2 5 mg/L,12.5 mg/L,25 mg/L,50 mg/L,100 mg/L,200 mg/L. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be 98.169 mg/L. This value indicates that the substance 3',6'-bis(diethylamino)-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one is toxic to algae and can be classified as Aquatic chronic category 3 as per the CLP criteria.

Thus, based on experimental study conducted by SSS with EC50=13.4 mg/L , it can be concluded that the target chemical 3',6'-Bis(N,N-diethylamino)-3H-spiro[isobenzofuran-1,9'-xanthen]-3-one (CAS no. 509-34-2) is toxic to aquatic algae and thus can be classified in Aquatic Chronic 3 category as per the CLP criteria.

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