Bromoethane

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed ptotocols, with no deviations from standard test guidelines and no methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

76-96-4

IUPAC Name:

76-96-4

Constituent 2

Reference substance name:

Bromoethane

EC Number:

200-825-8

EC Name:

Bromoethane

Cas Number:

74-96-4

Molecular formula:

C2H5Br

IUPAC Name:

bromoethane

Details on test material:

Lot number : 9-347
Appearance : colorless liquid
Assay= 99.7 %
Acidity (HBr) < 0.01 %

Sampling and analysis

Details on sampling:

After 24, 48 and 72 h , a sample less than 1 ml is taken under agitation.

Test solutions

Details on test solutions:

The study was performed using 120 ml glass bottles stoppered with PTFE bungs ans sealed with aluminium caps, containing 50 ml of test solution inoculated with an algal suspension so that initial call concentration was equal to 1x10E4 cells/ml. The algal concentration was measured daily. Analytical chemistry and physico-chemical measurements were carried out at the beginning and the end of the test.

The appearance of the test solutions was visually checked at the beginning and at the ned of the test. Solutions were found to be clear, colourless, cloudy over period of the test. No precipitation was observed at the end of the test.

Test organisms

Test organisms (species):

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

Details on test organisms:

Strain CCAP 278/4
Obtained from Culture Center of Algae and Protozoa

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Post exposure observation period:

Not done

Test conditions

Hardness:

Ultrapur water : resistivity > 18 Mohm

Test temperature:

Between 22 and 24°C

pH:

Between 7.21 and 7.31 at the beginning and between 7.13 and 7.44 at the end of teh study

Dissolved oxygen:

Between 8.3 and 8.7 mg/l at the beginning and between 8.0 and 9.7 mg/l at the end of the study

Salinity:

No data

Nominal and measured concentrations:

Measured concentrations were < 80% of nominal concentrations. So the measured concentrations were used to determine the effective concentartions.
Nominal concentrations from 98.77 to 500 mg/l with geometric progression of 1.5.

Details on test conditions:

Test flasks were incubated at 23±1°C continuously shaken and constantly illuminated.

3 replicatess were prepared by tested concentrations.
3 control flasks were prepared with water and inoculum algal and 3 with only water.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, purity > 99.95 %

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

150 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: not determined

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

99.2 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: not determined

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

200 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: not determined

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

99.2 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: not determined

Details on results:

Microscopic observation confirmed that the algae appeared normal at the end of the test in comparison to the control: the normal form of the unicellular algae is crescent shaped cell with an average lenght of 5-10 µm.

Results with reference substance (positive control):

The validity criteria of the study were respected: the increase in cell edensity (R), measured in the control solution between the end and the beginning of the test, was greater than a factor of 16 (R = 105) ; the final concentrations of ethyl bromide were maintained within the designated limit of 80% of the initial concentrations in non-inoculated flasks.

Reported statistics and error estimates:

NOEC were determined using Dunnett method.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test, toxicity to aquatic algae of the test material was determined to be EC50 > 100 mg/l.

Executive summary:

With an EC50 (72 h) on Pseudokirchnerella subcapitata well above 100 mg/l, ethyl bromide don't need to be considered as toxic for aquatic algae.

The test material does not require classification according to Regulation 1272/2008.