2,4'-difluorobenzophenone

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

Study period:

13.06.2006 - 16.06.2006

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,4'-difluorobenzophenone

EC Number:

206-441-7

EC Name:

2,4'-difluorobenzophenone

Cas Number:

342-25-6

Molecular formula:

C13H8F2O

IUPAC Name:

(2-fluorophenyl)(4-fluorophenyl)methanone

Details on test material:

- Name of test material (as cited in study report):2,4-difluorobenzophenone
- Physical state: liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1, 2, 5, 10, 20, 50, 100 ml WAF/l
- Sampling method: 2 x 50 ml of stock solution
- Sample storage conditions before analysis: Freezer a -21ºC

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Diatom algae
- Source (laboratory, culture collection): DHI, Water & Enviroment
- Method of cultivation: stock culture

ACCLIMATION
- Acclimation period: None
- Culturing media and conditions (same as test or not): same

Study design

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

19ºC

pH:

8.0

Salinity:

28 ‰

Nominal and measured concentrations:

Stock solution made by 500 mg substance dissolved in 500 ml test media. Nominal concentration: 1000 mg/l.
Substance was not fully dissolved, therfore a test was taken from the middle of the volumetric flask (water accomodated fraction = WAF)

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol, CAS No. : 591-35-5

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

0.31 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

dissolved

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

8.82 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

dissolved

Basis for effect:

biomass

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.34 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

dissolved

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

0.68 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

dissolved

Basis for effect:

biomass

Details on results:

pH in control was > 1 (1.1) but this is assessed not to have influence on the result.

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- EC50: 1.63 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Cell density increased by a factor of more than 16 during test, results for reference substance within acceptable range, 1.0-2.20 mg/l %

Conclusions:

EC50(72 h) of 2,4'-difluorobenzophenone, CAS No. 342-25-6 is 0.82 mg/L for Skelotonema costatum.