9,9-bis-(methoxymethyl)fluorene

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 1.0, 3.2, 10.0, 18.7, 31.9, 56.5, and 102 mg/l
- Sampling method: one sample was taken from each flask and the number of particles per mL were anaylsed via Coulter Counter model TAII

Vehicle:

yes

Details on test solutions:

test substance was dissolved into DMSO and sonicated for approximately 1 hour. This stock was further diluted with DMSO. Water accomodated fractions were prepared by stirring aliquots of medium containing test substance without DMSO for 20h in a dark room at approximately 20C. After a phase separation period of approx 4h, the clear middle layer of each extract was siphoned off.

Test organisms (species):

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

Details on test organisms:

The culture was supplied by ATCC. A preculture of algae in the exponential growth phase was prepared as detailed in the protocol.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Details on test conditions:

A suspension of algae in the algal medium containing 1E6 cells/ml was prepared by dilution of preculture. Addion of 1.0 mL of this algal suspension to 100 mL of the appropriate aqueous solutions of the test substance in the test flasks, yielded a mean inoculum cell density, measured in the control cultures, of 1.6E4 cells/mL and a test substance concentration/loading rate series of 0, 1.0, 3.2, 10.0, 18.7, 31.9, 56.5, and 102 mg/L

The test was carried out in duplicate with two control containing algae only, two controls containing algae and DMSO, and a single background series containing test substance without algae.
All falsks were incubated at 23 +/- 1C and shaken (approximately 100 rpm) in a Gallenkamp orbital shaker. The light intensity radiated by the flyorescent lamps was within the standard range of 60-120 umol/s/m^2.
One sample was taken from each flask after 0, 24, 51, and 71.5h and the number of algal cells per ml were determined.
The pH was measured as the statart (medium without algae) and after 71.5h in selected cultures. The morphology of the algae was examined visually with the aid of a microscope at the start and end of the test.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 6.8 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Remarks on result:

other: based on highest tested concentration (measured values)

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (not specified)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

>= 5.7 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 102 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EL90

Effect conc.:

> 102 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

>= 2.7 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Remarks on result:

other: 1.0 - 3.2

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

>= 46.4 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Remarks on result:

other: 31.9 - 56.5

Duration:

72 h

Dose descriptor:

EL90

Effect conc.:

> 102 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Details on results:

The EL50 with regards to growth rate (ErL50) was found to be >102 mg/l. The EbL values were lower than the ErL50 values.
By comparison to the growth values of algal suspensions exposed to the test substance with those of algal controls, the no observed effect concentration of Donor C20 was found to be 3.2 mg/l

Validity criteria fulfilled:

yes

Conclusions:

The 72h EC50 (growth rate) was determined to be above the limit of aqueous solubility (> 6.8 mg/l)

Executive summary:

.

Description of key information

In an GLP-compliant, OECD guideline study, the substance was tested up to the limit of aqueous solubility. The 72h EC50 value was determined to be greater than the limit of aqueous solubility (>6.8 mg/L). The NOEC was determined to be 2.4 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

2.4 mg/L

Additional information

It is not appropriate to include an EC50 value for the chemical safety assessment above as this is determined to be greater than the limit of aqueous solubility.